東北大学研究者紹介

キクガワ　ゴウタ

菊川　豪太

Gota Kikugawa

所属

流体科学研究所　ナノ流動研究部門　分子複合系流動研究分野

職名

准教授

学位

博士（工学）（東京大学）
修士（工学）（東京大学）

researchmap

https://researchmap.jp/read0138541

J-GLOBAL ID

200901097861370811

経歴 5

2016年4月～継続中

東北大学　流体科学研究所　准教授
2011年4月～ 2016年3月

東北大学　流体科学研究所　講師
2007年4月～ 2011年3月

東北大学　流体科学研究所　助教
2007年1月～ 2007年3月

東北大学　流体科学研究所　助手
2006年4月～ 2006年12月

独立行政法人理化学研究所　協力研究員

学歴 3

東京大学　工学系研究科　機械工学専攻

2001年4月～ 2006年3月
東京大学　工学部　産業機械工学科

1999年4月～ 2001年3月
東京大学　教養学部　理科I類

1997年4月～ 1999年3月

委員歴 1

日本機械学会熱工学部門　広報委員

2021年4月～継続中

所属学協会 4

日本熱物性学会
日本伝熱学会
日本機械学会
日本伝熱学会

研究キーワード 6

輸送現象
分子動力学
熱工学
Transport Phenomena
Molecular Dynamics
Thermal Engineering

研究分野 2

ものづくり技術（機械・電気電子・化学工学） / 流体工学 /
ものづくり技術（機械・電気電子・化学工学） / 熱工学 /

受賞 10

武藤栄次賞

2022年3月　日本設計工学会
平成30年度日本伝熱学会学術賞

2019年5月　日本伝熱学会　分子スケール熱伝搬解析に基づく液体の熱伝導メカニズムと分子構造との関係の解明
平成30年度科学技術分野の文部科学大臣表彰若手科学者賞

2018年4月　文部科学省　有機分子修飾膜の分子構造に基づく界面熱輸送制御の研究
平成28年度日本伝熱学会貢献賞

2017年5月　日本伝熱学会
日本機械学会熱工学部門講演論文表彰

2014年11月　日本機械学会　架橋を有するアモルファスポリマー材料における熱輸送機構の解明
平成24年度日本伝熱学会学術賞

2013年5月　日本伝熱学会　脂質二重膜の構造と熱伝導特性
日本熱物性学会賞論文賞

2011年11月　日本熱物性学会　長鎖ポリマー液体の熱伝導率:分子間及び分子内エネルギー伝搬の寄与についての分子動力学的研究
平成21年度日本伝熱学会奨励賞

2010年5月　日本伝熱学会　自己組織化単分子膜における熱輸送特性の分子動力学的研究
2008年度（第86期）日本機械学会熱工学部門講演論文表彰

2009年11月　日本機械学会　SAM-溶媒界面における界面熱抵抗特性の分子論的研究
日本機械学会奨励賞（研究）

2009年4月　日本機械学会　水およびLennard-Jones流体の気液界面における局所・瞬時的構造に関する分子動力学解析の研究

︎全件表示 ︎最初の5件までを表示

論文 173

Constructing and characterizing various multi-component crosslinked epoxy resins based on molecular dynamics simulations with a curing reaction model

Yinbo Zhao, Gota Kikugawa, Keiichi Shirasu, Yoshiaki Kawagoe, Tomonaga Okabe

Polymer　297　126817-126817　2024年3月
出版者・発行元：Elsevier BV
DOI： 10.1016/j.polymer.2024.126817 　

ISSN：0032-3861
Dissipative Particle Dynamics Simulation for Reaction-Induced Phase Separation of Thermoset/Thermoplastic Blends

Yoshiaki Kawagoe, Gota Kikugawa, Keiichi Shirasu, Yuuki Kinugawa, Tomonaga Okabe

The Journal of Physical Chemistry B　2024年2月19日
出版者・発行元：American Chemical Society (ACS)
DOI： 10.1021/acs.jpcb.3c07756 　

ISSN：1520-6106

eISSN：1520-5207
Development of cat-GRRM/MC/MD method for the simulation of cross-linked network structure formation with molecular autocatalysis

Yingxiao Xi, Hironobu Fukuzawa, Shoji Fukunaga, Gota Kikugawa, Yinbo Zhao, Yoshiaki Kawagoe, Tomonaga Okabe, Naoki Kishimoto

Molecular Catalysis　552　113680-113680　2024年1月
出版者・発行元：Elsevier BV
DOI： 10.1016/j.mcat.2023.113680 　

ISSN：2468-8231
Molecular dynamics simulations for interfacial structure and affinity between carboxylic acid-modified Al2O3 and polymer melts

Takamasa Saito, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys, Momoji Kubo

The Journal of Chemical Physics　159　(16)　2023年10月27日
出版者・発行元：AIP Publishing
DOI： 10.1063/5.0169721 　

ISSN：0021-9606

eISSN：1089-7690

詳細を見る詳細を閉じる

Controlling the dispersion state of nanoparticles in a polymer matrix is necessary to produce polymer nanocomposites. The surface modification of nanoparticles is used to enable their dispersion in polymers. Moreover, molecular dynamics (MD) simulations are useful for revealing the interfacial properties between nanoparticles and polymers to aid in the design of materials. In this study, the effect of surface coverage, modifier length, and polymer species on the interfacial structure and affinity between surface-modified Al2O3 and polymer melts were investigated using all-atom MD simulations. Hexanoic, decanoic, and tetradecanoic acids were used as surface modifiers, and polypropylene (PP), polystyrene (PS), and poly (methyl methacrylate) (PMMA) were used as polymers. The work of adhesion Wadh and the work of immersion Wimm were selected as quantitative measures of affinity. Wadh was calculated using the phantom-wall approach, and Wimm was calculated by simply subtracting the surface tension of polymers γL from Wadh. The results showed that Wadh and Wimm were improved by surface modification with low coverage, owing to a good penetration of the polymer. The effect of modifier length on Wadh and Wimm was small. Whereas Wadh increased in the following order: PP &lt; PS &lt; PMMA, Wimm increased as follows: PMMA &lt; PS &lt; PP. Finally, the trend of Wadh and Wimm was organized using the Flory–Huggins interaction parameter χ between the modifier and the polymer. This study demonstrates that the interfacial affinity can be improved by tuning the surface coverage and modifier species depending on the polymer matrix.
Molecular-scale investigation on relationship between thermal conductivity and the structure of crosslinked epoxy resin

Yinbo Zhao, Gota Kikugawa, Yoshiaki Kawagoe, Keiichi Shirasu, Tomonaga Okabe

International Journal of Heat and Mass Transfer　198　123429-123429　2022年12月
出版者・発行元：Elsevier BV
DOI： 10.1016/j.ijheatmasstransfer.2022.123429 　

ISSN：0017-9310
Effect of surface modifier and solvent on the affinity between the surface-modified solid and organic solvent: A molecular dynamics study

Takamasa Saito, Ryo Takebayashi, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys

AIP Advances　12　(10)　105206-105206　2022年10月1日
出版者・発行元：AIP Publishing
DOI： 10.1063/5.0119681 　

eISSN：2158-3226

詳細を見る詳細を閉じる

To control the dispersibility of surface-modified nanoparticles in fluid, it is important to evaluate the affinity between surface-modified nanoparticles and solvents and elucidate the effect of surface modification on the affinity at the molecular level. In this study, the effect of the chain length of the surface modifier and solvent on the work of adhesion Wadh was investigated for the carboxylic acid-modified Al2O3/ n-alkane interface by molecular dynamics simulations using the phantom-wall method. Here, we adopted hexanoic acid, decanoic acid, and octadecanoic acid as the surface modifiers and n-hexane, n-decane, and n-dodecane as the solvents. At a surface coverage of 100%, the effect of the modifier length on Wadh was small because the solvent did not penetrate any modifier layers with a dense packing state. At a surface coverage of 50%, the solvent penetration was good except for the octadecanoic acid modifier, and Wadh for the decanoic acid modifier was higher than that for the hexanoic acid and octadecanoic acid modifiers. For the decanoic acid modifier with a surface coverage of 50%, the effect of the solvent length on Wadh was small because the density distributions of the modifier and solvent near the interface were almost the same in all solvent systems. Solvent penetration was evaluated using the overlap parameter, which is the degree of overlap of the density distribution. A large penetration resulted in high Wadh. We demonstrated that the affinity between surface-modified nanoparticles and solvents can be increased by ensuring high modifier-solvent penetration via adjusting the surface coverage and surface modifier.
シアネート硬化エポキシ樹脂の熱機械特性に関する実験的評価と分子動力学シミュレーション

Yoshiaki Kawagoe, Shohei Komori, Gota Kikugawa, Keiichi Shirasu, Tomonaga Okabe

Journal of the Japan Society for Composite Materials　48　(4)　134-141　2022年7月15日
出版者・発行元：The Japan Society for Composite Materials
DOI： 10.6089/jscm.48.134 　

ISSN：0385-2563

eISSN：1884-8559
Multiscale modeling of process-induced residual deformation on carbon-fiber-reinforced plastic laminate from quantum calculation to laminate scale finite-element analysis

Yoshiaki Kawagoe, Kenji Kawai, Yuta Kumagai, Keiichi Shirasu, Gota Kikugawa, Tomonaga Okabe

Mechanics of Materials　170　104332-104332　2022年7月
出版者・発行元：Elsevier BV
DOI： 10.1016/j.mechmat.2022.104332 　

ISSN：0167-6636
(Invited) Nanoscale Wetting and Its Connection with Macroscopic Young's Equation 招待有り査読有り

Yasutaka Yamaguchi, Hiroki Kusudo, Carlos Bistafa, Donatas Surblys, Takeshi Omori, Gota Kikugawa

ECS Transactions　108　(4)　93-102　2022年5月

DOI： 10.1149/10804.0093ecst 　
Uncovering the Mechanism of Size Effect on the Thermomechanical Properties of Highly Cross-Linked Epoxy Resins 国際誌

Yinbo Zhao, Gota Kikugawa, Yoshiaki Kawagoe, Keiichi Shirasu, Naoki Kishimoto, Yingxiao Xi, Tomonaga Okabe

The Journal of Physical Chemistry B　126　(13)　2593-2607　2022年3月24日
出版者・発行元：None
DOI： 10.1021/acs.jpcb.1c10827 　

ISSN：1520-6106

eISSN：1520-5207
Density Functional Theory for Polymer Phase Separations Induced by Coupling of Chemical Reaction and Elastic Stress 査読有り

Yutaka Oya, Gota Kikugawa, Tomonaga Okabe, Toshihiro Kawakatsu

Advanced Theory and Simulations　5　(1)　2100385-2100385　2022年1月
出版者・発行元：None
DOI： 10.1002/adts.202100385 　

ISSN：2513-0390

eISSN：2513-0390
Methodology and meaning of computing heat flux via atomic stress in systems with constraint dynamics 査読有り

Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

Journal of Applied Physics　130　(21)　215104-215104　2021年12月7日
出版者・発行元：None
DOI： 10.1063/5.0070930 　

ISSN：0021-8979

eISSN：1089-7550
Obtaining heat flux via atomic stress in systems with many-body interactions and constrained dynamics 査読有り

Donatas SURBLYS, Hiroki MATSUBARA, Gota KIKUGAWA, Taku OHARA

Proceedings of the 2nd Asian Conference on Thermal Science　20321　2021年10月
Effect of molecular structure and molecular scale interaction on thermal conductivity of fluorocarbon liquids: A molecular dynamics study 査読有り

Shinsuke Kokubo, Hiroki Matsubara, Donatas Surblys, Gota Kikugawa, Taku Ohara

Proceedings of the 2nd Asian Conference on Thermal Science　20322　2021年10月
Relation between the internal molecular structure and thermomechanical properties of multi-component epoxy resin 査読有り

Yinbo Zhao, Gota Kikugawa, Naoki Kishimoto, Yoshiaki Kawagoe, Keiichi Shirasu, Tomonaga Okabe

Proceedings of the 2nd Asian Conference on Thermal Science　20311　2021年10月
Thermal conduction over PEG-terminated SAM/water interface with different SAM chain lengths 査読有り

Gota Kikugawa, Leton Chandra Saha, Takashi Yagi, Yuichiro Yamashita, Masahide Sato, Taku Ohara

Proceedings of the 2nd Asian Conference on Thermal Science　20312　2021年10月
Erratum: "Evaluation of the work of adhesion at the interface between a surface-modified metal oxide and an organic solvent using molecular dynamics simulations" [J. Chem. Phys. 154, 114703 (2021)]. 国際誌

Takamasa Saito, Eita Shoji, Masaki Kubo, Takao Tsukada, Gota Kikugawa, Donatas Surblys

The Journal of chemical physics　155　(6)　069901-069901　2021年8月14日

DOI： 10.1063/5.0062003 　
Thermoset resin curing simulation using quantum-chemical reaction path calculation and dissipative particle dynamics 査読有り

Yoshiaki Kawagoe, Gota Kikugawa, Keiichi Shirasu, Tomonaga Okabe

Soft Matter　17　(28)　6707-6717　2021年6月18日
出版者・発行元：None
DOI： 10.1039/d1sm00600b 　

ISSN：1744-683X

eISSN：1744-6848
Amine/epoxy stoichiometric ratio dependence of crosslinked structure and ductility in amine‐cured epoxy thermosetting resins 国際誌国際共著査読有り

Nobuyuki Odagiri, Keiichi Shirasu, Yoshiaki Kawagoe, Gota Kikugawa, Yutaka Oya, Naoki Kishimoto, Fumio S. Ohuchi, Tomonaga Okabe

Journal of Applied Polymer Science　138　(23)　50542-50542　2021年6月15日
出版者・発行元：None
DOI： 10.1002/app.50542 　

ISSN：0021-8995

eISSN：1097-4628
Evaluation of the work of adhesion at the interface between a surface-modified metal oxide and an organic solvent using molecular dynamics simulations 国際誌査読有り

Takamasa Saito, Eita Shoji, Masaki Kubo, Takao Tsukada, Gota Kikugawa, Donatas Surblys

The Journal of Chemical Physics　154　(11)　114703-114703　2021年3月21日
出版者・発行元：None
DOI： 10.1063/5.0040900 　

ISSN：0021-9606

eISSN：1089-7690
Comparison of molecular heat transfer mechanisms between water and ammonia in the liquid states 国際誌査読有り

Hiroki Matsubara, Gota Kikugawa, Taku Ohara

International Journal of Thermal Sciences　161　106762-106762　2021年3月
出版者・発行元：None
DOI： 10.1016/j.ijthermalsci.2020.106762 　

ISSN：1290-0729
Heat Conduction Performance over a Poly(ethylene glycol) Self-Assembled Monolayer/Water Interface: A Molecular Dynamics Study 国際誌査読有り

Leton C. Saha, Gota Kikugawa

The Journal of Physical Chemistry B　125　(7)　1896-1905　2021年2月25日
出版者・発行元：American Chemical Society (ACS)
DOI： 10.1021/acs.jpcb.0c09385 　

ISSN：1520-6106

eISSN：1520-5207
Molecular dynamics study on flow structure inside a thermal transpiration flow field 国際誌査読有り

Hiroki Yamaguchi, Gota Kikugawa

Physics of Fluids　33　(1)　012005-012005　2021年1月8日
出版者・発行元：None
DOI： 10.1063/5.0034146 　

ISSN：1070-6631

eISSN：1089-7666
Molecular dynamics simulation of cross-linking processes and material properties for epoxy resins using first-principle calculation combined with global reaction route mapping algorithms 国際誌国際共著査読有り

Yutaka Oya, Masahiro Nakazawa, Keiichi Shirasu, Yuki Hino, Kyosuke Inuyama, Gota Kikugawa, Jing Li, Riichi Kuwahara, Naoki Kishimoto, Hiroki Waizumi, Masaaki Nishikawa, Anthony Waas, Nobuyuki Odagiri, Andrew Koyanagi, Marco Salviato, Tomonaga Okabe

Chemical Physics Letters　762　138104-138104　2021年1月
出版者・発行元：None
DOI： 10.1016/j.cplett.2020.138104 　

ISSN：0009-2614

eISSN：1873-4448
Molecular Dynamics Simulation on Surface Nanobubble at the Graphite-water Interface with Pentanol Surfactants

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

Proceedings of the Twentieth International Symposium on Advanced Fluid Information　151-152　2020年10月
Output density quantification of electricity generation by flowing deionized water on graphene 国際誌国際共著査読有り

Kei Kuriya, Kotaro Ochiai, Golap Kalita, Masaki Tanemura, Atsuki Komiya, Gota Kikugawa, Taku Ohara, Ichiro Yamashita, Fumio S. Ohuchi, M. Meyyappan, Seiji Samukawa, Katsuyoshi Washio, Takeru Okada

Applied Physics Letters　117　(12)　123905-123905　2020年9月21日
出版者・発行元：None
DOI： 10.1063/5.0018862 　

ISSN：0003-6951

eISSN：1077-3118
Structure–Property Correlation Study for Organic Photovoltaic Polymer Materials Using Data Science Approach 国際共著査読有り

Yue Huang, Jingtian Zhang, Edwin S. Jiang, Yutaka Oya, Akinori Saeki, Gota Kikugawa, Tomonaga Okabe, Fumio S. Ohuchi

124　(24)　12871-12882　2020年6月18日
出版者・発行元：None
DOI： 10.1021/acs.jpcc.0c00517 　

ISSN：1932-7447

eISSN：1932-7455
Cross-Plane and In-Plane Heat Conductions in Layer-by-Layer Membrane: Molecular Dynamics Study 査読有り

Yoshiaki Kawagoe, Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

Langmuir　36　(23)　6482-6493　2020年6月16日
出版者・発行元：American Chemical Society (ACS)
DOI： 10.1021/acs.langmuir.0c00845 　

ISSN：0743-7463

eISSN：1520-5827
Erratum: “Interpretation of Young’s equation for a liquid droplet on a flat and smooth solid surface: Mechanical and thermodynamic routes with a simple Lennard-Jones liquid” [J. Chem. Phys. 150, 044701 (2019)] 査読有り

Yasutaka Yamaguchi, Hiroki Kusudo, Donatas Surblys, Takeshi Omori, Gota Kikugawa

The Journal of Chemical Physics　152　(17)　179901-179901　2020年5月7日
出版者・発行元：AIP Publishing
DOI： 10.1063/5.0010630 　

ISSN：0021-9606

eISSN：1089-7690
Erratum to “A molecular dynamics study of thermal boundary resistance over solid interfaces with an extremely thin liquid film” (International Journal of Heat and Mass Transfer (2020) 147, (S0017931019306490), (10.1016/j.ijheatmasstransfer.2019.118949)) 査読有り

Xiao Liu, Donatas Surblys, Yoshiaki Kawagoe, Abdul Rafeq Bin Saleman, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

International Journal of Heat and Mass Transfer　150　2020年4月

DOI： 10.1016/j.ijheatmasstransfer.2020.119307 　

ISSN：0017-9310

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© 2020 Elsevier Ltd The publisher regrets that Fig. 7 was published incorrectly. The correct version of Fig. 7 is indicated below and has been updated on the original article online. [Figure presented] The publisher would like to apologise for any inconvenience caused.
Evaluation of thermal conductivity and its structural dependence of a single nanodiamond using molecular dynamics simulation 査読有り

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Taku Ohara

Diamond and Related Materials　102　107669　2020年2月

DOI： 10.1016/j.diamond.2019.107669 　

ISSN：0925-9635

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© 2019 Elsevier B.V. In the present study, we investigated thermal conductivity and its structural dependence of a spherical nanodiamond with 2.5 nm in diameter using molecular dynamics simulation. We briefly discussed the difficulty of computing the thermal conductivity of a free nanoparticle using conventional methods and here we derived it from the non-equilibrium molecular dynamics simulation of a composite system where a nanodiamond is sandwiched between two solid blocks. The structural dependence was examined by applying this method based on a composite system to the 2.5 nm nanodiamonds having different ratios of 3- and 4-coordinate carbons (termed sp2-like and sp3-like carbons, respectively), which were obtained from annealing at different temperatures. The thermal conductivity of the nanodiamond decreased from 28 to 10 W/(m·K) with decreasing ratio of sp3-like carbons until the number of sp2-like bonds exceeded that of sp3-like bonds. When sp2-like bond became richer than sp3-like bond, the thermal conductivity was less sensitive to further increase of the ratio of sp2-like carbons. Based on the consideration of the heat transfer associated with a single C[sbnd]C bond, we interpreted that this structural dependence reflects the heat transfer characteristics of sp3- or sp2-like bond, whichever is more abundant. This interpretation, as well as the methodology, is helpful for understanding thermal conductivity of nanodiamonds and other carbon nanomaterials.
A molecular dynamics study of thermal boundary resistance over solid interfaces with an extremely thin liquid film 査読有り

Xiao Liu, Donatas Surblys, Yoshiaki Kawagoe, Abdul Rafeq Bin Saleman, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

International Journal of Heat and Mass Transfer　147　118949　2020年2月

DOI： 10.1016/j.ijheatmasstransfer.2019.118949 　

ISSN：0017-9310

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© 2019 Elsevier Ltd We investigated the characteristics of thermal energy transport over two solid surfaces joined via an extremely thin liquid film where the liquid molecules are under the influence of both solid surfaces simultaneously. Using non-equilibrium molecular dynamics simulations, the thermal resistance between the two solid surfaces was examined for different thickness of liquid film and different alignment (in-plane orientation) of the two solid surfaces. Both solid surfaces were the (1 1 0) plane of face centered cubic lattice, and two different combinations of alignment, i.e., either parallel or crossed to each other, were examined. The thermal resistance between the solid surfaces was decomposed into the thermal boundary resistance at the solid-liquid interfaces and the thermal resistance of the liquid film, which were analyzed separately. The results showed that when the liquid film thickness is equal or less to four molecular dimensions, both the film thickness and the surface alignment have significant influence on the thermal resistance. Specifically, when the liquid film is a single layer of liquid molecules (LLM), the thermal resistance between solid surfaces is extremely low when compared with the cases of more LLM, and increases with increasing liquid density. In contrast, when the film is composed of two or three LLM, the solid-liquid interfacial thermal resistance decreases with increasing liquid density, and a discontinuous increase occurs as the number of LLM changes from two to three. As for the effect of surface alignment, it was found that the parallel surface alignment gives a lower thermal resistance than the crossed surface alignment.
Introducing self-organized maps (SOM) as a visualization tool for materials research and education 国際誌国際共著査読有り

Jimin Qian, Nam Phuong Nguyen, Yutaka Oya, Gota Kikugawa, Tomonaga Okabe, Yue Huang, Fumio S. Ohuchi

Results in Materials　4　100020　2019年12月

DOI： 10.1016/j.rinma.2019.100020 　
Molecular dynamics analysis of surfactant effect on water-gas interface

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

Proceedings of the 19th International Symposium on Advanced Fluid Information　202-203　2019年11月
A study on nano-scale interfacial phenomena of surface-modified nanoparticle suspensiondy on nano-scale interfacial phenomena of surface-modified nanoparticle suspension

Eita Shoji, Masaki Kubo, Takao Tsukada, Atsuki Komiya, Gota Kikugawa

Proceedings of the 19th International Symposium on Advanced Fluid Information　174-175　2019年11月
Construction of polydisperse polymer model and investigation of heat conduction: A molecular dynamics study of linear and branched polyethylenimine 査読有り

Yoshiaki Kawagoe, Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

Polymer　180　121721　2019年10月10日

DOI： 10.1016/j.polymer.2019.121721 　

ISSN：0032-3861

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© 2019 Elsevier Ltd Molecular dynamics (MD) simulation is a powerful tool for investigating the molecular mechanism of heat conduction in polymers. However, existing MD studies are mostly on monodisperse polymers and the effect of polydispersity, which typically occurs in commercial polymers, remains to be clarified. In this work, various types of polydisperse polyethylenimine (PEI) composed of molecules having different molecular weights and branching structures were constructed by in silico step-growth polymerization. The effect of the polydispersity and molecular structure on heat conduction in PEI was investigated using all-atom MD simulations. The number and weight fraction distributions of the polydisperse purely-linear PEI agreed well with the Flory-Schulz distributions, and therefore it can be concluded that the in silico polymerization used in this work reasonably mimics the step-growth-like polymerization observed in the actual synthesis of PEI. Thermal conductivity increased with increase in the radius of gyration dependent on the degree of branching of the molecules. In addition, thermal conductivity of a polydisperse PEI exhibited a similar value to that of a monodisperse PEI of a representative polymer chain in the polydisperse system. By analyzing in detail the thermal energy transfer among and inside molecules, their microscopic mechanisms could be understood and it was discovered that the average molecular weight is a critical factor in determining heat conduction.
Data Analysis of Multi-Dimensional Thermophysical Properties of Liquid Substances Based on Clustering Approach of Machine Learning 国際共著査読有り

Gota Kikugawa, Yuta Nishimura, Koji Shimoyama, Taku Ohara, Tomonaga Okabe, Fumio S. Ohuchi

Chemical Physics Letters　728　109-114　2019年8月

DOI： 10.1016/j.cplett.2019.04.075 　
Application of atomic stress to compute heat flux via molecular dynamics for systems with many-body interactions 査読有り

Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

Physical Review E　99　(5)　051301(R)　2019年5月14日

DOI： 10.1103/PhysRevE.99.051301 　

ISSN：2470-0045

eISSN：2470-0053

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© 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Although the computation of heat flux and thermal conductivity either via Fourier's law or the Green-Kubo relation has become a common task in molecular dynamics simulation, contributions of three-body and larger many-body interactions have always proved problematic to compute. In recent years, due to the success when applying to pressure tensor computation, atomic stress approximation has been widely used to calculate heat flux, where the lammps molecular dynamics package is the most prominent propagator. We demonstrated that the atomic stress approximation, while adequate for obtaining pressure, produces erroneous results in the case of heat flux when applied to systems with many-body interactions, such as angle, torsion, or improper potentials. This also produces incorrect thermal conductivity values. To remedy this deficiency, by starting from a strict formulation of heat flux with many-body interactions, we reworked the atomic stress definition which resulted in only a simple modification. We modified the lammps package accordingly to demonstrate that the new atomic stress approximation produces excellent results close to that of a rigid formulation.
All- and one-particle distribution functions at nonequilibrium steady state under thermal gradient 査読有り

Hiroki Matsubara, Gota Kikugawa, Taku Ohara

Physical Review E　99　(5)　052110　2019年5月10日

DOI： 10.1103/PhysRevE.99.052110 　

ISSN：2470-0045

eISSN：2470-0053

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© 2019 American Physical Society. We provide a concrete expression for the phase-space distribution function at nonequilibrium steady state under a constant thermal gradient, which is a typical system of the nonequilibrium molecular dynamics simulation of heat conduction. First, the phase-space distribution function of all particles in a local volume is formulated. Our formulation explicitly takes into account the entropy production due to the change in equilibrium thermodynamic variables in addition to the traditional entropy production described by the spatial gradients and fluxes of equilibrium thermodynamic variables. This treatment is necessary to explain the nonequilibrium response of a quantity that has no equilibrium correlation with mass and heat fluxes and is essential to correctly deduce one-particle distribution functions from the all-particle one. From the all-particle distribution function, we derive the Green-Kubo relations that express the one-particle distribution functions of density and velocity in terms of equilibrium correlation functions and verify these expressions using the molecular dynamics simulation of a Lennard-Jones liquid. These nonequilibrium one-particle distribution functions are sufficiently tractable for practical use, such as for the analytical evaluation of the nonequilibrium average of physical quantities.
Molecular dynamics study on thermal energy transfer in bulk polyacrylic acid 査読有り

Yoshiaki Kawagoe, Donatas Surblys, Gota Kikugawa, Taku Ohara

AIP Advances　9　025302　2019年2月

DOI： 10.1063/1.5080432 　
Interpretation of Young’s equation for a liquid droplet on a flat and smooth solid surface: Mechanical and thermodynamic routes with a simple Lennard-Jones liquid 査読有り

Yasutaka Yamaguchi, Hiroki Kusudo, Donatas Surblys, Takeshi Omori, Gota Kikugawa

Journal of Chemical Physics　150　(4)　044701　2019年1月
出版者・発行元：None
DOI： 10.1063/1.5053881 　

ISSN：0021-9606

eISSN：1089-7690
Mechanism of Thermal Energy Transfer in Nanoscale Solid-Liquid Systems

Masahiko Shibahara, Gota Kikugawa, Taku Ohara

Proceedings of the 18th International Symposium on Advanced Fluid Information　124-125　2018年11月
A molecular dynamics study on the thermal rectification effect at the solid-liquid interfaces between the face-centered cubic (FCC) of gold (Au) with the surfaces of (100), (110) and (111) crystal planes facing the liquid methane (CH4) 査読有り

Abdul Rafeq, bin Saleman, Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Molecular Simulation　45　(1)　68-79　2018年10月

DOI： 10.1080/08927022.2018.1535177 　
Kinetic model for molecular transport of liquid mixtures in the vicinity of solid-liquid interfaces 査読有り

Mamoru Hirasawa, Gota Kikugawa, Takeo Nakano, Taku Ohara

Proceedings of the 16th International Heat Transfer Conference　IHTC16-22176　2018年8月
Microscopic picture of heat conduction in liquid ethylene glycol by molecular dynamics simulation: Difference from the monohydric case 査読有り

Hiroki Matsubara, Gota Kikugawa, Mamoru Ishikiriyama, Seiji Yamashita, Taku Ohara

International Journal of Heat and Mass Transfer　121　1033-1038　2018年6月

DOI： 10.1016/j.ijheatmasstransfer.2018.01.060 　

ISSN：0017-9310

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© 2018 Elsevier Ltd The present study investigates the molecular-scale heat transfer in the liquid of ethylene glycol, which is widely used as heat transfer media. First, by combining existing molecular models, we developed a new united atom model of ethylene glycol, and showed that this model reasonably reproduces the experimental thermal conductivity. Using the non-equilibrium molecular dynamics simulations with this model, we characterized the heat transfers due to different kinds of inter- and intramolecular interactions on the basis of a picture that a single pair interaction is a path of heat transfer. These characteristics were compared with those of ethanol (Matsubara et al., 2017) to elucidate the molecular mechanism which realizes an enhanced thermal conductivity because of an additional hydroxylation on ethanol. The results indicate that the thermal conductivity enhancement occurs because the additional heat paths provided by the second hydroxyl group increases the amount of heat conduction owing to all of the van der Waals, Coulomb, and covalent interactions. In particular, the increase in the number of the paths associated with the intermolecular Coulomb interaction between the non-hydrogen bonding hydroxyl groups is prominent and consequently the Coulomb interaction, which is an efficient heat carrier, performs the largest amount of heat conduction in ethylene glycol. Although the second hydroxyl group also increases the number of hydrogen bonds, the direct heat transfer via the hydrogen bonds accounts for only a small portion of the total heat conduction. On the other hand, this augmentation of hydrogen bond, since it keeps a dense molecular packing against the increase in molecular volume, is indispensable in increasing the density of heat paths.
A molecular dynamics study on thermophysical and transport properties of fluorinated alkane liquids 査読有り

Gota Kikugawa, Naoki Minami, Yingping Fang, Mitsuru Nemoto, Hiroki Matsubara, Taku Ohara

International Heat Transfer Conference　2018-August　7019-7024　2018年

ISSN：2377-424X

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© 2018 International Heat Transfer Conference. All rights reserved. Thermophysical and transport properties of heat media, which are extensively utilized in heat transfer devices such as refrigerating and air-conditioning equipment, are inherently determined from microscopic components like molecular interactions and molecular-scale structure of liquid. An essential understanding of these microscopic information are of critical importance for designing and exploring liquid materials having desired properties. Here we performed molecular dynamics (MD) simulation on fluorocarbon liquids, which are prevailing as typical coolants in industrial products, in order to examine thermophysical properties such as a liquid-vapor phase change property and thermal conductivity at the bulk liquid state. In the present study, we have developed a new transferable potential model for fluorocarbon and hydrofluorocarbons by modifying partial charges of the OPLS-AA force field based on the ab initio molecular orbital calculation. We demonstrated that our developed potential models well reproduce experimental data of a liquid-vapor phase change property and thermal conductivity for several fluorocarbons having different chain lengths. Not only physical property itself, but the underlying molecular-scale mechanism was also examined, i.e., the microscopic mechanism to realize the thermal conductivity was precisely investigated by decomposing macroscopic thermal conductivity into microscopic building blocks.
Mechanism of thermal energy transfer in nanoscale solid-liquid systems

Masahiko Shibahara, Gota Kikugawa, Taku Ohara

Proceedings of the 17th International Conference on Advanced Fluid Information　74-75　2017年11月
A molecular dynamics study on the thermal energy transfer and momentum transfer at the solid-liquid interfaces between gold and sheared liquid alkanes 査読有り

Abdul Rafeq bin Saleman, Hari Krishna Chilukoti, Gota Kikugawa, Masahiko Shibahara, Taku Ohara

INTERNATIONAL JOURNAL OF THERMAL SCIENCES　120　273-288　2017年10月
出版者・発行元：ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER
DOI： 10.1016/j.ijthermalsci.2017.06.014 　

ISSN：1290-0729

eISSN：1778-4166

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Solid-liquid (S-L) interfaces of linear alkane liquids contacting two parallel solid walls of gold with three types of face-centered cubic (FCC) of (100), (110) and (111) crystal planes were examined using nonequilibrium molecular dynamics simulations (NEMD). The liquid alkanes were sheared by the two parallel solid walls sliding at a constant speed and in opposite directions, which generates viscous heating in the liquid. The effect of the molecular length of the linear alkane liquids, methane, butane, octane, and tetracosane, was investigated in terms of the thermal energy transfer and momentum transfer at the S-L interfaces. The gap distance between the surface layer of the solid atoms and the adsorption layer of the liquid molecules was measured as a key feature of the interface. The slip length, which was defined as the extrapolated velocity of liquid into the solid walls where the tangential velocity vanishes, was measured and the mechanism that determines its magnitude was examined. The gap distance and the slip length were correlated with the molecular length of the liquid alkanes. The thermal boundary resistance at the S-L interfaces was measured and it was also correlated with the gap distance and molecular length of liquid alkanes. It was found that the differences in the surface structure of the solid walls between the three types of crystal planes affect the slip length at the S-L interfaces. The present results suggest that the factors affecting the thermal energy transfer and momentum transfer at the S-L interfaces were the gap distance, which differs significantly depending on the molecular length of liquid, and the surface structure of the solid walls. (C) 2017 Elsevier Masson SAS. All rights reserved.
Thermal boundary conductance and energy transfer modes over the interfaces of various self-assembled monolayers and solvents: A molecular dynamics study 査読有り

Gota Kikugawa, Mitsuru Nemoto, Taku Ohara

Proceedings of the 9th JSME-KSME Thermal and Fluids Engineering Conference　2017年10月
Equivalence of the EMD- and NEMD-based decomposition of thermal conductivity into microscopic building blocks 査読有り

Hiroki Matsubara, Gota Kikugawa, Mamoru Ishikiriyama, Seiji Yamashita, Taku Ohara

JOURNAL OF CHEMICAL PHYSICS　147　(11)　114104　2017年9月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.4990593 　

ISSN：0021-9606

eISSN：1089-7690

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Thermal conductivity of a material can be comprehended as being composed of microscopic building blocks relevant to the energy transfer due to a specific microscopic process or structure. The building block is called the partial thermal conductivity (PTC). The concept of PTC is essential to evaluate the contributions of various molecular mechanisms to heat conduction and has been providing detailed knowledge of the contribution. The PTC can be evaluated by equilibrium molecular dynamics (EMD) and non-equilibrium molecular dynamics (NEMD) in different manners: the EMD evaluation utilizes the autocorrelation of spontaneous heat fluxes in an equilibrium state whereas the NEMD one is based on stationary heat fluxes in a non-equilibrium state. However, it has not been fully discussed whether the two methods give the same PTC or not. In the present study, we formulate a Green-Kubo relation, which is necessary for EMD to calculate the PTCs equivalent to those by NEMD. Unlike the existing theories, our formulation is based on the local equilibrium hypothesis to describe a clear connection between EMD and NEMD simulations. The equivalence of the two derivations of PTCs is confirmed by the numerical results for liquid methane and butane. The present establishment of the EMD-NEMD correspondence makes the MD analysis of PTCs a robust way to clarify the microscopic origins of thermal conductivity. Published by AIP Publishing.
Understanding the chain length dependence of thermal conductivity of liquid alcohols at 298 K on the basis of molecular-scale energy transfer 査読有り

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

FLUID PHASE EQUILIBRIA　441　24-32　2017年6月
出版者・発行元：ELSEVIER SCIENCE BV
DOI： 10.1016/j.fluid.2016.12.019 　

ISSN：0378-3812

eISSN：1879-0224

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Many of the specifics of microscopic energy transfer in liquids are not sufficiently understood in spite of their importance in controlling heat transport in practical devices. The present study aims to clarify the details of microscopic energy transfer in associated liquids with the aid of non-equilibrium molecular dynamics (NEMD) simulations on the liquids of linear alcohols from ranging ethanol to decanol at normal conditions. The NEMD simulations reasonably reproduce the experimentally observed chain length dependence of thermal conductivity. The microscopic energy transfer corresponding to each type of interatomic interactions are analyzed in relation to the liquid structures and molecular morphologies. Our analysis shows that the heat transfer by the Coulomb interaction has only a limited contribution to the alcohol thermal conductivity. Molecular morphology also has little effect. Rather, the chain length dependence of the thermal conductivity is determined by the result of the competition between the intermolecular and intramolecular energy transfers. The new insights obtained in the present study are a step towards a molecular theory of the thermal conductivity of liquids. (C) 2016 Elsevier B.V. All rights reserved.
Molecular dynamics study on the role of hydroxyl groups in heat conduction in liquid alcohols 査読有り

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER　108　749-759　2017年5月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.ijheatmasstransfer.2016.12.045 　

ISSN：0017-9310

eISSN：1879-2189

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On the basis of non-equilibrium molecular dynamics (NEMD) simulation for alcohols from ethanol to tetracosanol, the present study analyzes the molecular-level energy transfer in associated liquids for the first time. Direct evaluation of the energy transfer by each interatomic interaction reveals a counter-intuitive result that in liquid alcohols the Coulomb interaction does not transfer heat more than the van der Waals interaction even for short chain species like ethanol. In addition, by comparing the NEMD analysis on alcohols with those of alkanes, we discuss a molecular mechanism by which alcohol has a higher thermal conductivity than alkane in view of molecular heat transfer. It is shown that hydroxyl OH, not only provides heat paths for the Coulomb interaction, but also increases the number of heat paths for the vdW and the intramolecular interactions. Consequently, the part of the heat transfer by the vdW interaction is replaced with more efficient transfers by the Coulomb and intramolecular interactions, and therefore a higher thermal conductivity occurs. The insights obtained from the present study update the view of microscopic heat transfer in associated liquid towards the molecular theory of thermal conductivity of liquids, which is currently immature in comparison with those of gases and solids. (C) 2016 Elsevier Ltd. All rights reserved.
Clustering Approach for Multidisciplinary Optimum Design of Cross-Linked Polymer 査読有り

Yutaka Oya, Gota Kikugawa, Tomonaga Okabe

MACROMOLECULAR THEORY AND SIMULATIONS　26　(2)　1600072　2017年3月
出版者・発行元：WILEY-V C H VERLAG GMBH
DOI： 10.1002/mats.201600072 　

ISSN：1022-1344

eISSN：1521-3919

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This paper proposes a new and systematic approach for optimum design of thermosetting resin systems based on molecular-dynamics simulations. Specifically, the results of simulations for chemical reaction (cross-linking) and mechanical properties of epoxy resin are clustered with a self-organizing map (SOM) that enables to comprehensibly visualize the characteristics of complex structured polymers. Moreover, the scatter-plot matrix (SPM) is introduced to analyze the specific data. Thus, SOM is used to find common features in a molecular structure, and SPM helps to clarify molecular-scale mechanism in the clusterization. Through the analysis, the authors find that base resins with multireactive functional groups contribute to superior mechanical properties, and these properties stem from the hydrogen-bond network distributed throughout the system. The approach, which is thought to be one of chemical informatics, has broad ranges of applications that are not limited to epoxy resin but can be applied to any kind of thermosetting resins.
Thermal energy transport over the solvent interface of self-assembled monolayers with different fluorination 査読有り

Gota Kikugawa, Mitsuru Nemoto, Taku Ohara

Proceedings of the Asian Conference on Thermal Sciences 2017　2017年3月
Thermal rectification effects on solid-liquid interfaces between face-centered cubic (FCC) lattice and a simple liquid 査読有り

Abdul Rafeq, bin Saleman, Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of the Asian Conference on Thermal Sciences 2017　2017年3月
A molecular dynamics study on the thermal transport properties and the structure of the solid-liquid interfaces between face centered cubic (FCC) crystal planes of gold in contact with linear alkane liquids 査読有り

Abdul Rafeq Bin Saleman, Had Krishna Chilukoti, Gota Kikugawa, Masahiko Shibahara, Taku Ohara

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER　105　168-179　2017年2月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.ijheatmasstransfer.2016.09.069 　

ISSN：0017-9310

eISSN：1879-2189

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Solid-liquid (S-L) interfaces of liquid alkane in contact with three types of face-centered cubic (FCC) of gold with the surfaces of (100), (110) and (111) crystal planes facing with linear alkane liquids were examined using nonequilibrium molecular dynamics (NEMD) simulations where constant heat flux was applied. The effect of molecular length of the linear alkane liquids, which are methane (CH4), butane (C4H10), octane (C8H18), hexadecane (C16H34) and tetracosane (C24H50), with respect to the thermal boundary resistance (TBR) of the S-L interfaces, were investigated. It was found that on the solid wall surface of (110) crystal plane, where lattice-scale corrugation exists, molecules of the liquid alkanes are adsorbed into the corrugation. This tendency is obvious at low temperatures and it fades at higher temperatures. The gap distance between the surface layer of atoms of the solid walls and the adsorption layer of liquid alkanes molecules was correlated with the length of liquid alkane molecules and the number density of solid atoms at the surface layer. The TBR over each S-L interfaces were obtained based on the temperature jump at the interfaces and the heat flux, and it was found that the TBR is influenced by the length of liquid alkane molecules, the number density of solid atoms at the surface layer and the gap distance. It is concluded that the TBR is influenced by the gap distance of the S-L interfaces and the number density of solid atoms at the surface layer, which varies depending on the length of liquid alkane molecules. (C) 2016 Elsevier Ltd. All rights reserved.
6.3.1 脂質二重膜中の熱エネルギー伝搬特性招待有り

小原拓, 中野雄大, 菊川豪太

佐藤岳彦他編, 高度物理刺激と生体応答, 第6章計測・予測と応用, 6.3 数値解析, 養賢堂　170-173　2017年
Mechanism of Temperature Dependent Thermal Transport across the Interface between Self-Assembled Monolayer and Water

Shih-Wei Hung, Gota Kikugawa, Junichiro Shiomi

Journal of Physical Chemistry C　120　(47)　26678-26685　2016年12月
出版者・発行元：AMER CHEMICAL SOC
DOI： 10.1021/acs.jpcc.6b09516 　

ISSN：1932-7447

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The thermal boundary conductance between water and self-assembled monolayer was studied using nonequilibrium molecular dynamics simulations. Different thermal transport behaviors were observed for hydrophobic and hydrophilic self-assembled monolayers. In the temperature range between 280 and 340 K, the thermal boundary conductance was found to depend on the temperature for hydrophobic self-assembled monolayers. On the contrary, the difference in thermal boundary conductance at different temperatures was slight for hydrophilic self-assembled monolayers. The correlations in velocity and density between terminal atoms of self-assembled monolayer and water molecules within the interface region were analyzed to understand the mechanism of thermal transport across the interface. The vibrational density of states calculation indicated that the temperature dependence does not originate from the overlap of phonon spectrum. The analysis of radial density distribution revealed that the temperature dependence is mainly attributed to the number of water molecules surrounding the terminal atoms of self-assembled monolayers.
Molecular thermal energy transfer in binary mixture of simple liquids

Yingping Fang, Gota Kikugawa, Hiroki Matsubara, Takeshi Bessho, Seiji Yamashita, Taku Ohara

FLUID PHASE EQUILIBRIA　429　293-300　2016年12月
出版者・発行元：ELSEVIER SCIENCE BV
DOI： 10.1016/j.fluid.2016.09.013 　

ISSN：0378-3812

eISSN：1879-0224

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Molecular thermal energy transfer in liquid mixtures was investigated using non-equilibrium molecular dynamics (NEMD) simulations of heat conduction in a series of binary mixture liquids with various compositions. Mixtures of argon and krypton were selected as simple liquids which were modeled using the Lennard-Jones (LJ) interaction potential. Thermal conductivities for these mixtures in a saturated state at a constant temperature (127 K) were compared with respect to mixture composition, i.e., molar fraction of each component. According to the molecular energy transfer mechanism, microscopic heat conduction flux can be decomposed into two molecular-scale contributions: one from self transportation, which includes transport of kinetic energy and potential energy by molecular motion, and the other via the contribution of intermolecular energy transfer based on intermolecular interaction. The intermolecular energy transfer, which is the dominant source of macroscopic heat conduction flux in liquids, can be decomposed into contributions from various pair interactions, which in the present study are energy transfers via the paths Ar-Ar, Ar-Kr, and Kr-Kr. The above contributions to heat conduction were evaluated quantitatively. It was found that the composition dependence of the first self transportation contribution is mostly caused by the differences of their thermodynamic states, and the variation of total thermal conductivity with the composition is dominated by the second intermolecular energy transfer contribution, which accounts for about 80% of the total. The contributions of individual interaction paths were analyzed with our new concept of atomistic heat path [Matsubara et al., J. Chem. Phys., 142 (2015), 164509]. It was found that these contributions are mostly affected by the number densities of the interaction paths in the first neighbor shell. The molecular-scale internal structure of the liquid is changed by changes in composition, which affects the efficiency of the energy transfer by a single intermolecular interaction. A sensitivity analysis of LJ cross-molecular parameters was done using various combining rules. We found that the decomposed energy transfer contribution of interaction paths, Ar-Ar and Kr-Kr may be affected by changing the LJ parameters of Ar-Kr. (C) 2016 Elsevier B.V. All rights reserved.
Non-equilibrium molecular dynamics simulation as a method of calculating thermodynamic coefficients

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

FLUID PHASE EQUILIBRIA　421　1-8　2016年8月
出版者・発行元：ELSEVIER SCIENCE BV
DOI： 10.1016/j.fluid.2016.03.019 　

ISSN：0378-3812

eISSN：1879-0224

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A method is proposed in the present study, by which the specific heat at constant pressure, c(p), and the thermal expansion coefficient, alpha(p), at different temperatures along an isobar can be derived from a single run of non-equilibrium molecular dynamics (NEMD) at using a steady temperature gradient. This study aims to demonstrate the method and examine its validity in the NEMD simulation. For Lennard-Jones fluids, it is shown that the c(p) and alpha(p) obtained from the NEMD simulations are in good agreement with those calculated in a traditional manner from the equilibrium fluctuations. The results of the present study suggest that a NEMD simulation with heat conduction is useful not only to measure thermal conductivity but also to determine these thermodynamic coefficients. In particular, there is a possibility that the present method is applicable even to heterogeneous systems, to which the standard method is difficult to apply. (C) 2016 Elsevier B.V. All rights reserved.
Molecular dynamics simulation of crosslinked epoxy resins: Curing and mechanical properties

Tomonaga Okabe, Yutaka Oya, Koichi Tanabe, Gota Kikugawa, Kenichi Yoshioka

EUROPEAN POLYMER JOURNAL　80　78-88　2016年7月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.eurpolymj.2016.04.019 　

ISSN：0014-3057

eISSN：1873-1945

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We performed molecular dynamics (MD) simulation that includes multidisciplinary characteristics from synthesis to mechanical properties of epoxy resin. First, to reproduce the actual chemical reaction between matrix and curing agents, we conducted curing simulation wherein the activation energy and heat of formation are considered for the chemical reaction. Subsequently, we performed MD simulations using cross-linked structure obtained from curing simulation to derive density and Young's modulus. Results indicated that cross-linked structures involving both activation energy and heat of formation could reproduce experiment results that are evaluated using differential scanning calorimetry (DSC) measurements and mechanical tests. The simulated results imply that electrostatic interaction plays an important role in Young's modulus. The density of the hydrogen bond between the oxygen of the hydroxyl group and the hydrogen atom is a key factor for the difference in Young's modulus for each base resin. These findings confirm that MD simulation is a potential alternative to experiments for the appropriate material selection of epoxy resin. (C) 2016 Elsevier Ltd. All rights reserved.
Structure and Mass Transport Characteristics at the Intrinsic Liquid Vapor Interfaces of Alkanes

Had Krishna Chilukoti, Gota Kikugawa, Taku Ohara

JOURNAL OF PHYSICAL CHEMISTRY B　120　(29)　7207-7216　2016年7月
出版者・発行元：AMER CHEMICAL SOC
DOI： 10.1021/acs.jpcb.6b05332 　

ISSN：1520-6106

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In this paper, an instantaneous interface definition has been used to study the intrinsic structure and self-diffusion coefficient in the vicinity of the liquid vapor interfaces of decane and tetracosane at three different temperatures using molecular dynamics simulations, and the results have been compared with those obtained on the basis of the conventional Gibbs dividing surface (time- and space-averaged interface). The alkane molecules were modeled using the united atom NERD force field. Partial layered structures of alkane molecules at the liquid vapor interface are observed as a pinned structure of alkane liquids based on the intrinsic interface. This kind of characteristic has not been observed in the density profiles obtained based on the Gibbs dividing surface. By examining the orientation order parameter and radius of gyration of the alkane molecules, it was observed that the alkane molecules were preferentially oriented to be more parallel to the intrinsic interface than to the Gibbs dividing surface, and the shape of the alkane molecules is slightly changed in the vicinity of the liquid vapor interfaces. The self-diffusion coefficient parallel to the intrinsic interface was examined using the Green Kubo relation, where the projection of the velocity in the parallel direction to the local intrinsic interface is used in the velocity correlation function. It was found that the self-diffusion coefficient in the direction parallel to the intrinsic interface changes as the position approaches the interface in a more obvious manner as compared with the self-diffusion coefficient obtained with respect to the Gibbs dividing surface. These results suggest that the use of an instantaneous interface definition allowed us to capture sharp variations in transport properties which are originating due to steeper structure at the liquid vapor interfaces.
A molecular dynamics study on molecular diffusion in liquids of water and IPA in the vicinity of solid surfaces and in liquid mixture

Y. Naruke, J. Suzuki, T. Nakano, G. Kikugawa, T. Ohara

Proceedings of the First Pacific Rim Thermal Engineering Conference　2016年
Mass transport and structure of liquid n-alkane mixtures in the vicinity of α-quartz substrate

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

RSC (Royal Society of Chemistry) Advances　6　(102)　99704-99713　2016年
出版者・発行元：None
DOI： 10.1039/c6ra22398b 　

ISSN：2046-2069
Mechanism of thermal energy transfer in Nanoscale Solid-Liquid Systems

Masahiko Shibahara, Gota Kikugawa, Hari Krishna Chilukoti, Taku Ohara

Proceedings of The Sixteenth International Symposium on Advanced Fluid Information　84-85　2016年
Molecular Dynamics Study on Thermal Transpiration Flow in Nanochannels

Hiroki Yamaguchi, Gota Kikugawa

Proceedings of The Sixteenth International Symposium on Advanced Fluid Information　150-151　2016年
Molecular mechanism of heat conduction in linear alcohol liquids: Effect of chain length

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

Proceedings of the 11th Asian Thermophysical Properties Conference　2016年
Molecular dynamics mechanism of heat conduction in 1-butyl-3-methylimidazolium ionic liquid

Joji Haneda, Gota Kikugawa, Taku Ohara

Proceedings of the 11th Asian Thermophysical Properties Conference　2016年
Molecular thermophysical properties toward the design of liquids and soft matters

Taku Ohara, Gota Kikugawa, Hiroki Matsubara

Proceedings of the 11th Asian Thermophysical Properties Conference　2016年
Molecular Transport Phenomena of Liquids Confined in the Nanoscopic Structures

Gota Kikugawa, Yoichi Naruke, Jo Suzuki, Takeo Nakano, Taku Ohara

Proceedings of Thirteenth International Conference on Flow Dynamics　418-419　2016年
Molecular-Scale Structure of Liquid Alkane Mixtures in the Vicinity of α-Quartz Substrate

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of Thirteenth International Conference on Flow Dynamics　416-417　2016年
Molecular dynamics mechanism to determine viscosity of thermal medium liquids

Satoru Harada, Gota Kikugawa, Taku Ohara

Proceedings of the 4th International Forum on Heat Transfer　2016年
Molecular mechanism for thermal boundary conductance over fluorinated SAM-solvent interfaces

Mitsuru Nemoto, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

Proceedings of the 4th International Forum on Heat Transfer　2016年
Thermal rectification over solid-liquid interfaces of gold (Au) contacting liquid methane (CH4)

Abdul Rafeq Saleman, Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of the 4th International Forum on Heat Transfer　2016年
Self-diffusion Coefficient and Structure of Binary n-Alkane Mixtures at the Liquid-Vapor Interfaces

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

JOURNAL OF PHYSICAL CHEMISTRY B　119　(41)　13177-13184　2015年10月
出版者・発行元：AMER CHEMICAL SOC
DOI： 10.1021/acs.jpcb.5b07189 　

ISSN：1520-6106

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The self-diffusion coefficient and molecular-scale structure of several binary n-alkane liquid mixtures in the liquid-vapor interface regions have been examined using molecular dynamics simulations. It was observed that in hexane-tetracosane mixture hexane molecules are accumulated in the liquid-vapor interface region and the accumulation intensity decreases with increase in a molar fraction of hexane in the examined range. Molecular alignment and configuration in the interface region of the liquid mixture change with a molar fraction of hexane. The self-diffusion coefficient in the direction parallel to the interface of both tetracosane and hexane in their binary mixture increases in the interface region. It was found that the self-diffusion coefficient of both tetracosane and hexane in their binary mixture is considerably higher in the vapor side of the interface region as the molar fraction of hexane goes lower, which is mostly due to the increase in local free volume caused by the local structure of the liquid in the interface region.
Hydrodynamic consideration of the finite size effect on the self-diffusion coefficient in a periodic rectangular parallelepiped system

Gota Kikugawa, Takeo Nakano, Taku Ohara

JOURNAL OF CHEMICAL PHYSICS　143　(2)　2015年7月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.4926841 　

ISSN：0021-9606

eISSN：1089-7690

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In the present study, we use molecular dynamics (MD) simulations to provide an insight into the system size effect on the self-diffusion coefficient of liquids in the periodic rectangular parallelepiped system, from the hydrodynamic perspective. We have previously shown that in the rectangular box system, the diffusivity exhibits anomalous behaviors, i.e., the diffusion tensor appears to be anisotropic despite the bulk liquid simulation and the diffusion component in the direction along the short side of rectangular box with a high aspect ratio exceeding the diffusivity in the infinite system [Kikugawa et al., J. Chem. Phys. 142, 024503 (2015)]. So far, the size effect on the diffusivity has been intensively studied in the cubic system and has been interpreted quite well by the theoretical considerations employing the hydrodynamic interaction. Here, we have extended the hydrodynamic theory to be applied to periodic rectangular box systems and compared the theoretical predictions with MD simulation results. As a result, the diffusivity predicted by the hydrodynamic theory shows good agreement with the MD results. In addition, the system size effect was examined in a rod-shaped rectangular box in which the two shorter side lengths were equivalent and a film-type rectangular box in which the two longer side lengths were equivalent. It is of interest that we found that the aspect ratio, at which the diffusivity coincides with that in the infinite system, is a universal constant independent of the cross-sectional area for the rod system or the thickness for the film system. By extracting the universal structure in the hydrodynamic description, we also suggested a simplified approximate model to accurately predict the size effect on the diffusivity over a practical range of aspect ratios. (C) 2015 AIP Publishing LLC.
Local thermal transport of liquid alkanes in the vicinity of α-quartz solid surfaces and thermal resistance over the interfaces: A molecular dynamics study 査読有り

Hari Krishna Chilukoti, Gota Kikugawa, Masahiko Shibahara, Taku Ohara

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics　91　(5)　2015年5月20日
出版者・発行元：American Physical Society
DOI： 10.1103/PhysRevE.91.052404 　

ISSN：1550-2376 1539-3755

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Thermal transport in liquid n-alkanes in the vicinity of α-quartz substrates and thermal boundary resistance between the liquid n-alkanes and the α-quartz substrates have been investigated using nonequilibrium molecular dynamics simulations. The study considers two liquid alkanes, methane and decane, and three crystal orientations of α-quartz substrate terminated with -H or -OH groups. The local thermal conductivity (LTC), defined in the same manner as with macroscopic thermal conductivity, is used to measure the efficiency of thermal energy transport of the liquids in the vicinity of the solid surface. The variations in the LTC of the liquid alkanes in the layered region next to the surface of the substrate were examined. The modeled LTC values of the alkanes were found to oscillate in the solid-liquid interface region. These fluctuations were typically proportional to the oscillations in the local density profile. The correlation between the thermal conductivity and density was linear in the bulk liquid region. The correlation between LTC and local density in the first adsorption layer is not a straightforward extension of that of the bulk liquid, which is mostly due to the specific molecular-scale ordering structure that occurs in the liquids formed by the proximity of the solid substrate. Thermal boundary resistance between the liquid alkanes and the quartz substrate was also evaluated. It was observed that thermal boundary resistance is relatively large when the in-plane molecular-scale structure in the first adsorption layer is sparse, and is lower when the liquid structure is dense in the adsorption layer.
A molecular dynamics study on mass transport characteristics in the vicinity of Si02-water/IPA interfaces

Yoichi Naruke, Shuichi Kosaka, Takeo Nakano, Gota Kikugawa, Taku Ohara

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER　84　584-591　2015年5月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.ijheatmasstransfer.2015.01.051 　

ISSN：0017-9310

eISSN：1879-2189

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Mass transport in the vicinity of solid-liquid interfaces exhibits anomalous characteristics that differ from those in bulk liquids. These anomalous transport properties play a crucial role in recent nanoscale applications such as wet processing in semiconductor fabrication, surface modification by chemical treatment, and dynamic coating. In the present study, interfaces between solid Si02 and liquid water or isopropyl alcohol (IPA), which are typically used in the semiconductor industry, were investigated using molecular dynamics (MD) simulations. The molecular-scale structures of the adsorption layers of water or IPA molecules were examined, and self-diffusion coefficients of these liquids related to migration of molecules in the direction parallel to the interfaces were calculated. Both H- and OH-terminated SiO2 surfaces were investigated in this study. It was found that layered structures of water and IPA molecules form near the interfaces, and were influenced by the crystal plane orientation. To examine the influences of these structures on molecular transport, local self-diffusion coefficients of water and IPA were derived via MD simulation using two methods based on the mean square displacement and on the velocity auto correlation function. The present study focused on a system of two solid walls with a spacing on the order of 10 nm with the liquids confined in between. It was found that the self-diffusion coefficients of water and IPA are reduced in the vicinity of the interfaces. The self-diffusion coefficient of water approaches its bulk value when separated from the solid wall by approximately 2-3 nm, while in the case of IPA, the solid wall influences the liquid properties more deeply into the liquid phase. o 2015 Elsevier Ltd. All rights reserved.
Effects of molecular structure on microscopic heat transport in chain polymer liquids

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

JOURNAL OF CHEMICAL PHYSICS　142　(16)　2015年4月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.4919313 　

ISSN：0021-9606

eISSN：1089-7690

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In this paper, we discuss the molecular mechanism of the heat conduction in a liquid, based on nonequilibrium molecular dynamics simulations of a systematic series of linear- and branched alkane liquids, as a continuation of our previous study on linear alkane [T. Ohara et al., J. Chem. Phys. 135, 034507 (2011)]. The thermal conductivities for these alkanes in a saturated liquid state at the same reduced temperature (0.7T(c)) obtained from the simulations are compared in relation to the structural difference of the liquids. In order to connect the thermal energy transport characteristics with molecular structures, we introduce the new concept of the interatomic path of heat transfer (atomistic heat path, AHP), which is defined for each type of inter-and intramolecular interaction. It is found that the efficiency of intermolecular AHP is sensitive to the structure of the first neighbor shell, whereas that of intramolecular AHP is similar for different alkane species. The dependence of thermal conductivity on different lengths of the main and side chain can be understood from the natures of these inter-and intramolecular AHPs. (C) 2015 AIP Publishing LLC.
Effect of the computational domain size and shape on the self-diffusion coefficient in a Lennard-Jones liquid

Gota Kikugawa, Shotaro Ando, Jo Suzuki, Yoichi Naruke, Takeo Nakano, Taku Ohara

JOURNAL OF CHEMICAL PHYSICS　142　(2)　2015年1月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.4905545 　

ISSN：0021-9606

eISSN：1089-7690

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In the present study, molecular dynamics (MD) simulations on the monatomic Lennard-Jones liquid in a periodic boundary system were performed in order to elucidate the effect of the computational domain size and shape on the self-diffusion coefficient measured by the system. So far, the system size dependence in cubic computational domains has been intensively investigated and these studies showed that the diffusion coefficient depends linearly on the inverse of the system size, which is theoretically predicted based on the hydrodynamic interaction. We examined the system size effect not only in the cubic cell systems but also in rectangular cell systems which were created by changing one side length of the cubic cell with the system density kept constant. As a result, the diffusion coefficient in the direction perpendicular to the long side of the rectangular cell significantly increases more or less linearly with the side length. On the other hand, the diffusion coefficient in the direction along the long side is almost constant or slightly decreases. Consequently, anisotropy of the diffusion coefficient emerges in a rectangular cell with periodic boundary conditions even in a bulk liquid simulation. This unexpected result is of critical importance because rectangular fluid systems confined in nanospace, which are present in realistic nanoscale technologies, have been widely studied in recent MD simulations. In order to elucidate the underlying mechanism for this serious system shape effect on the diffusion property, the correlation structures of particle velocities were examined. (C) 2015 AIP Publishing LLC.
A molecular dynamics analysis of water/IPA liquid displacement in the vicinity of silica interface

Takeo Nakano, Shuichi Kosaka, Gota Kikugawa, Jo Suzuki, Yoichi Naruke, Taku Ohara

Proceedings of the Fifth International Symposium on Micro and Nano Technology　2015年
Influence of computational domain shape in molecular dynamics simulations on self-diffusion coefficient of bulk liquids

Gota Kikugawa, Jo Suzuki, Yoichi Naruke, Takeo Nakano, Taku Ohara

Proceedings of the Fifth International Symposium on Micro and Nano Technology　2015年
Kinetic model for transport of liquid molecules in the solid-liquid interface region: a molecular dynamics view

Jo Suzuki, Gota Kikugawa, Takeo Nakano, Taku Ohara

JSME Mechanical Engineering Letters　1　15-00353-15-00353　2015年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/mel.15-00353 　

ISSN：2189-5236

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Liquid molecules form ordered structures in the vicinity of the solid-liquid interface. Mass transport in the ordered structure exhibits decidedly different characteristics from the ordinary diffusion property governed by Ficks law. In order to analyze mass transport at this nanoscopic scale, we have monitored the PMF (potential of mean force) obtained from the number density of liquid molecules, which corresponds to the free energy change with respect to the molecular migration. Using this PMF profile, the kinetic process model to describe the molecular mobility inside these ordered structures was developed in this study. In order to verify whether the suggested kinetic model works correctly, molecular dynamics (MD) simulations of the liquid-solid interface system were performed. In a simple system consisting of a LJ liquid and flat solid walls, which are modeled by the continuum media interacting with liquid molecules, molecular adsorption and desorption phenomena were observed. In each process in which molecules migrate to the neighboring adsorption layer, the height of the free energy barrier was calculated using the PMF distribution. It was found that the PMF has a dominant influence on the molecular transport perpendicular to the wall and that the developed kinetic model can accurately predict the molecular mobility over the free energy barrier due to the adsorption and desorption process.
Analysis of molecular transport in the solid-liquid interface region based on the kinetic model

Jo Suzuki, Gota Kikugawa, Takeo Nakano, Taku Ohara

Proceedings of the 12th International Conference on Flow Dynamics　446-447　2015年
Atomistic heat path analysis of heat transfer in chain polymer liquids

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Seiji Yamashita, Taku Ohara

Proceedings of the 12th International Conference on Flow Dynamics　454-455　2015年
Control of thermal transport across a solid-liquid interface by using self-assembled monolayer

Shih-Wei Hung, Junichiro Shiomi, Gota Kikugawa

Proceedings of the Fifteenth International Symposium on Advanced Fluid Information　92-93　2015年
Interfacial properties of binary n-alkane mixtures at the liquid-vapor interfaces

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of the 12th International Conference on Flow Dynamics　456-457　2015年
Molecular dynamics study on thermal resistance of solid-liquid interfaces

Masahiko Shibahara, Taku Ohara, Gota Kikugawa

Proceedings of the Fifteenth International Symposium on Advanced Fluid Information　88-89　2015年
Molecular dynamics study on thermal transpiration flow

Hiroki Yamaguchi, Gota Kikugawa

Proceedings of the Fifteenth International Symposium on Advanced Fluid Information　90-91　2015年
Structure and transport properties of liquid alkanes in the vicinity of α-quartz surfaces

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

International Journal of Heat and Mass Transfer　79　846-857　2014年12月
出版者・発行元：None
DOI： 10.1016/j.ijheatmasstransfer.2014.08.089 　

ISSN：0017-9310

eISSN：1879-2189
A molecular dynamics study on heat conduction characteristics inside the alkanethiolate SAM and alkane liquid

Gota Kikugawa, Taku Ohara, Tohru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER　78　630-635　2014年11月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.ijheatmasstransfer.2014.07.040 　

ISSN：0017-9310

eISSN：1879-2189

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In the present study, we performed molecular dynamics (MD) simulations of the self-assembled monolayer (SAM) and alkane solvent interface. In particular, 1-dodecanethiol (C12H25S-) SAM chemisorbed on a gold substrate contacting with n-dodecane (C12H26) solvent was examined to compare the heat transfer mechanisms inside both the SAM and solvent phases from a microscopic viewpoint. The nonequilibrium MD (NEMD) simulation, in which a constant heat flux across the SAM interface was imposed, was performed. Here, we introduced the novel approach to clarify the molecular-scale mechanism on heat conduction in both SAM and alkane solvent. This approach enables us to decompose the macroscopic heat flux into the microscopic "building blocks", i.e., the contribution of energy transfer associated with molecular motion and those of energy exchange by intermolecular (nonbonded) and intramolecular (covalent bond) interactions. Interestingly, we have obviously demonstrated that inside the SAM layer, almost all of the energy is transferred by the intramolecular interaction along the alkyl chain. On the other hand, inside the alkane liquid, the intramolecular and intermolecular interactions have similar contributions to the total heat flux in spite of the same molecular structure and alkyl chain length as the SAM molecules. This striking difference in heat conduction mechanism originates from the ordering structure of alkyl chains in the SAM layer. (C) 2014 Elsevier Ltd. All rights reserved.
A Molecular Dynamics Study on Heat Transfer Characteristics Over the Interface of Self-Assembled Monolayer and Water Solvent

Gota Kikugawa, Taku Ohara, Tohru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME　136　(10)　2014年10月
出版者・発行元：ASME
DOI： 10.1115/1.4027910 　

ISSN：0022-1481

eISSN：1528-8943

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We performed molecular dynamics (MD) simulations of the interface which is comprised of self-assembled monolayer (SAM) and water solvent to investigate heat transfer characteristics. In particular, local thermal boundary conductance (TBC), which is an inverse of so-called Kapitza resistance, at the SAM-solvent interface was evaluated by using the nonequilibrium MD (NEMD) technique in which the one-dimensional thermal energy flux was imposed across the interface. By using two kinds of SAM terminal with hydrophobic and hydrophilic properties, the local TBCs of these interfaces with water solvent were evaluated, and the result showed a critical difference due to an affinity between SAM and solvent. In order to elucidate the molecular-scale mechanism that makes this difference, microscopic components contributing to thermal energy flux across the interface of hydrophilic SAM and water were evaluated in detail, i.e., the total thermal energy flux is decomposed into the heat transfer modes such as the contribution of molecular transport and that of energy exchange by molecular interactions. These heat transfer modes were also compared with those in the bulk water.
HEAT TRANSFER CHARACTERISTICS OVER THE INTERFACE OF ALKANETHIOLATE SAM AND ALKANE LIQUID

Gota Kikugawa, Taku Ohara, Tohru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

PROCEEDINGS OF THE ASME SUMMER HEAT TRANSFER CONFERENCE - 2013, VOL 1　2014年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS
DOI： 10.1115/HT2013-17607 　

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In the present study, we performed molecular dynamics (MD) simulations of the self-assembled monolayer (SAM) interface system in order to investigate heat transfer characteristics over the SAM/alkane solvent interface. 1-dodecanethiol (C12H25S-) SAM chemisorbed on a gold substrate contacting with n-dodecane (C12H26) solvent was examined to compare the microscopic heat transfer mechanisms inside both the SAM and solvent phases. The direct nonequilibrium MD (NEMD) simulation, in which a constant heat flux across the SAM interface was imposed, was performed. The heat flux through the system was decomposed into the microscopic "building blocks", i.e., the contribution of energy transfer associated with molecular motion and that of energy exchange by intermolecular (nonbonded) and intramolecular (covalent bond) interactions. Interestingly, inside the SAM layer, almost all of the energy is transferred by the intramolecular interaction along the alkyl chain. On the other hand, in the alkane liquid phase, the intramolecular and intermolecular interactions have comparable contributions to the total heat flux in spite of the same molecular structure and alkyl chain length as the SAM molecules. This difference in the heat transfer mechanism implies the relation between the ordering structure of alkyl chains and thermal conductivity in organic materials.
Molecular Dynamics Viewpoint on Heat Transfer Characteristics of Self-Assembled Monolayers and Polymeric Substances

Gota Kikugawa

Proceedings of the 8th US-Japan Joint Seminar on Nanoscale Transport Phenomena　21-21　2014年
Investigation of Thermal Resistance and Heat Conduction at α-Quartz-Liquid Alkane Interfaces Using Nonequilibrium Molecular Dynamics Simulations

Hari Krishna Chilukoti, Gota Kikugawa, Masahiko Shibahara, Taku Ohara

Proceedings of the 15th International Heat Transfer Conference　2014年
Thermal Resistance between Nano-Structured Surfaces and Liquids

Taku Ohara, Masahiko Shibahara, Gota Kikugawa, Hari Krishna Chilukoti

Proceedings of the 14th International Symposium on Advanced Fluid Information　134-135　2014年
Thermal Transport in Lipid Bilayers

Taku Ohara, Takeo Nakano, Gota Kikugawa

Proceedings of the Eleventh International Conference on Flow Dynamics　2014年
Structure and transport properties at the liquid-vapor interfaces of binary n-alkane mixtures

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of the 25th International Symposium on Transport Phenomena　2014年
Effect of crosslink formation on heat conduction in amorphous polymers

Gota Kikugawa, Tapan G. Desai, Pawel Keblinski, Taku Ohara

JOURNAL OF APPLIED PHYSICS　114　(3)　2013年7月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.4813505 　

ISSN：0021-8979

eISSN：1089-7550

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We performed molecular dynamics (MD) simulations on amorphous polyethylene (PE) and polystyrene (PS) in order to elucidate the effect of crosslinks between polymer chains on heat conduction. In each polymer system, thermal conductivities were measured for a range of crosslink concentration by using nonequilibrium MD techniques. PE comprised of 50 carbon atom long chains exhibited slightly higher conductivity than that of 250 carbon atom long chains at the standard state. In both cases for PE, crosslinking significantly increased conductivity and the increase was more or less proportional to the crosslink density. On the other hand, in the PS case, although the thermal conductivity increased with the crosslinking, the magnitude of change in thermal conductivity was relatively small. We attribute this difference to highly heterogeneous PS based network including phenyl side groups. In order to elucidate the mechanism for the increase of thermal conductivity with the crosslink concentration, we decomposed energy transfer into modes associated with various bonded and non-bonded interactions. (C) 2013 AIP Publishing LLC.
Molecular Heat Transfer in Lipid Bilayers With Symmetric and Asymmetric Tail Chains

Takeo Nakano, Gota Kikugawa, Taku Ohara

JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME　135　(6)　2013年6月
出版者・発行元：ASME
DOI： 10.1115/1.4023572 　

ISSN：0022-1481

eISSN：1528-8943

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Intramolecular energy transfer in polymer molecules plays a dominant role in heat conduction in polymer materials. In soft matter where polymer molecules form an ordered structure, the intramolecular energy transfer works in an anisotropic manner, which results in an anisotropic thermal conductivity. Based on this idea, thermal energy transfer in lipid bilayers, a typical example of soft matter, has been analyzed in the present study. Non-equilibrium molecular dynamics simulations were carried out on single component lipid bilayers with ambient water. In the simulations, dipalmitoyl-phosphatidyl-choline (DPPC), dilauroyl-phosphatidyl-choline (DLPC), and stearoyl-myristoyl-phosphatidyl-choline (SMPC), which have two alkyl chains with 16C atoms for each, 12C atoms for each, and 18 and 14C atoms, respectively, were used as lipid molecules. The thermal energy transfer has been decomposed to inter-and intramolecular energy transfer between individual molecules or molecular sites, and its characteristics were discussed. In the case of heat conduction in the direction across the membranes (cross-plane heat conduction), the highest thermal resistance exists at the center of the lipid bilayer, where lipid alkyl chains face each other. The asymmetric chain length of SMPC reduces this thermal resistance at the interface between lipid monolayers. The cross-plane thermal conductivities of lipid monolayers are 4.8-6.5 times as high as the ones in the direction parallel to the membranes (in-plane) for the cases of the tested lipids. The overall cross-plane thermal conductivities of the lipid bilayers are reduced to be approximately half of those of the monolayers, due to the thermal resistance at the interfaces between two monolayers. The lipid bilayer of SMPC with tail chains of asymmetric length exhibits the highest cross-plane thermal conductivity. These results provide detailed information about the transport characteristics of thermal energy in soft matter, which are new materials with design flexibility and biocompatibility. The results lead to their design to realize desired thermophysical properties and functions.
A molecular dynamics study on transport properties and structure at the liquid-vapor interfaces of alkanes

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER　59　144-154　2013年4月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.ijheatmasstransfer.2012.12.015 　

ISSN：0017-9310

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In this paper, self-diffusion and structure in the vicinity of liquid vapor interfaces of several species of n-alkanes are examined using molecular dynamics simulations. The united atom NERD force field was utilized to model the alkane molecules, and the obtained properties were validated by the reported experimental results. Surface tension was calculated based on the averaged pressures, and tail corrections were implemented based on the molecular virial formulae. Present surface tension results for butane, hexane and decane are in good agreement with experimental and other simulated values. Molecular orientation and chain conformation in the interface region were examined by observing the ordering parameter and radius of gyration for decane and tetracosane. In the interface region, molecules are preferentially oriented parallel to the interface and shape of the molecules is slightly flattened in the z-direction for both decane and tetracosane. With an increase in temperature, molecules are preferentially less parallel to the interface. The Einstein relation modified for confined regions was used to obtain the self-diffusion coefficient according to migration of molecules parallel to the interface. Self-diffusion coefficient increases in the interface region for both decane and tetracosane. This increase in self-diffusion coefficient has a correlation with decrease in density. The dependency of self-diffusion coefficient on density is nonlinear in the liquid and vapor side of the interface region and is linear in between the above two regions. Influence of chain length of the alkane molecules has been studied by comparing the physical and structural quantities of decane, tetracosane and hexatriacontane at the same reduced temperature. At the same reduced temperature, self-diffusion coefficient decreases with an increase in chain length in the interface region as well as in the bulk liquid region. All three alkanes show similar tendency of ordering and chain conformation at the interface at the same reduced temperature. (C) 2012 Elsevier Ltd. All rights reserved.
Report on the seventh U.S.-Japan Joint seminar on nanoscale transport phenomena-science and engineering 査読有り

B. A. Cola, H. Daiguji, C. Dames, N. Fang, K. Fushinobu, S. Inoue, G. Kikugawa, M. Kohno, S. Kumar, D. Y. Li, J. R. Lukes, J. A. Malen, A. J.H. McGaughey, O. Nakabeppu, K. Pipe, P. Reddy, S. Shen, L. Shi, M. Shibahara, Y. Taguchi, K. Takahashi, T. Yamamoto, T. Zolotoukhina

Nanoscale and Microscale Thermophysical Engineering　17　(1)　25-49　2013年1月1日

DOI： 10.1080/15567265.2012.745913 　

ISSN：1556-7265

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The seventh U.S.-Japan Joint Seminar on Nanoscale Transport Phenomena was held in Shima, Japan, from December 11 to 14, 2011. The goals of this joint seminar were to provide a critical assessment of the state of the art and future directions in the field of nanoscale transport phenomena and energy conversion processes, to foster U.S.-Japan collaborations, and to provide international exposure to a new generation of scientists in this field. Issues discussed in the joint seminar were organized in 10 topical sessions, including (1) nanoscale thermophysical measurements (2) optical characterization (3) thermal and molecular transport (4) phonon transport modeling (5) energy storage and conversion (6) nanoscale fluidics and phase change phenomena (7) biological and organic systems (8) interfacial thermal transport (9) novel thermoelectric and thermal management materials and (10) nanocarbon materials and devices. In addition to these topical sessions, the joint seminar featured an opening plenary session and a closing plenary session as well as an expert panel, where leading experts provided critical assessment of the past progress and addressed future directions in the field. In addition, an evening poster session provided opportunities for graduate and postdoc students to present their latest research results. About 35 researchers from Japan and 31 researchers from the United States participated in the meeting. The meeting was organized by S. Maruyama, K. Fushinobu, L. Shi, and J. Lukes together with about 20 other participants who served as session chairs. Summaries of different sessions of the seminar were prepared by the session and conference chairs and are collected into this report. © 2013 Taylor &amp Francis Group, LLC.
Investigation of Interfacial Properties at α-Quartz/Alkane Interfaces Using Molecular Dynamics Simulations

Hari Krishna Chikukoti, Gota Kikugawa, Taku Ohara

International Journal of Advanced Research in Engineering & Technology　4　(3)　68-76　2013年
MASS TRANSPORT CHARACTERISTICS OF WATER/IPA AT SILICA-LIQUID INTERFACES

Takeo Nakano, Shuichi Kosaka, Gota Kikugawa, Taku Ohara

PROCEEDINGS OF THE 11TH INTERNATIONAL CONFERENCE ON NANOCHANNELS, MICROCHANNELS, AND MINICHANNELS, 2013　2013年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS
DOI： 10.1115/ICNMM2013-73195 　

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Molecular dynamics simulations were performed in order to investigate the impact of temperature on molecular structure and mass transport properties in the vicinity of silica-water and/or iso-propyl alcohol (IPA) liquid film interfaces. Each of water and IPA liquid molecules form layered structures in the vicinity of the solid. Although temperature has an insignificant effect on the first layer from the solid, the layered structure at higher temperature decays farther away from the second layer comparing with that at lower temperature for both silica-water and silica-IPA systems. Moreover, interfusion of water and IPA molecules between silica substrates was simulated and molecular coverage on the substrates are analyzed for temperatures of 300 K and 350 K.
A Molecular Dynamics Study on Effect of Temperature on Diffusion in the Vicinity of an Alpha-Quartz Surface/Alkane Interfaces

Hari Krishna Chikukoti, Gota Kikugawa, Taku Ohara

Proceedings of the 4th International Symposium on Micro and Nanotechnology　2013年
A molecular dynamics study on mass transport properties in the vicinity of SiO2-water/IPA interfaces

Yoichi Naruke, Shuichi Kosaka, Takeo Nakano, Gota Kikugawa, Taku Ohara

Proceedings of the 4th International Symposium on Micro and Nanotechnology　2013年
Heat Conduction in Amorphous Polymers with Crosslink Formation

Gota Kikugawa, Pawel Keblinski, Taku Ohara

Proceedings of the 4th International Symposium on Micro and Nanotechnology　2013年
Molecular Dynamics Mechanism of Thermal Energy Transport in Liquid Methane Reproduced by All-Atom and United-Atom Models

Joji Haneda, Gota Kikugawa, Taku Ohara

Proceedings of the 4th International Symposium on Micro and Nanotechnology　2013年
Study of Alkane Chain Length Influence on Structure and Dynamic Properties at Intrinsic Liquid-Vapour Interfaces

Hari Krishna Chikukoti, Gota Kikugawa, Taku Ohara

Proceedings of the 12th International Symposium on Fluid Control, Measurement and Visualization (FLUCOME2013)　2013年
Thermal Transport Characteristics over the Interface of Alkanethiol SAM on a Copper Substrate and Water Solvent

Yoichi Naruke, Gota Kikugawa, Takeshi Bessho, Satoshi Takata, Taku Ohara

Proceedings of the 12th International Symposium on Fluid Control, Measurement and Visualization (FLUCOME2013)　2013年
Crosslinking Effect in Amorphous Polymers on Heat Transfer Characteristics

Gota Kikugawa, Pawel Keblinski, Taku Ohara

Proceedings of the Thirteenth International Symposium on Advanced Fluid Information　194-195　2013年
Thermal Resistance between Nano-Structured Surfaces and Liquids

Masahiko Shibahara, Taku Ohara, Gota Kikugawa

Proceedings of the Thirteenth International Symposium on Advanced Fluid Information　106-107　2013年
Surface Termination Effect on Structure of Decane Liquid in the Vicinity of Alpha-Quartz Surfaces

Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

Proceedings of the International Conference on Flow Dynamics 2013　2013年
Molecular Dynamics Study on Effect of Chain Length on Liquid-Vapor Interfacial Properties of alkanes

Hari Krishna Chikukoti, G. Kikugawa, T. Ohara

Proceedings of the 9th International Conference on Fluid Dynamics　2012年
Thermal Resistance between Nano-Structured Surfaces and Liquids

M. Shibahara, T. Ohara, G. Kikugawa

Proceedings of the 9th International Conference on Fluid Dynamics　2012年
A Molecular Dynamics Study on Molecular Scale Structure and Mass Transport Properties in the Vicinity of SiO2-Water/IPA Interfaces

S. Kosaka, G. Kikugawa, T. Nakano, T. Ohara

Proceedings of the 3rd International Forum on Heat Transfer　2012年
Molecular Dynamics Simulation of Liquid-Vapor Interfacial Properties of n-Alkanes

Hari Krishna Chikukoti, G. Kikugawa, T. Ohara

Proceedings of the 3rd International Forum on Heat Transfer　2012年
Energy dissipation in non-isothermal molecular dynamics simulations of confined liquids under shear

Hassan Berro, Nicolas Fillot, Philippe Vergne, Takashi Tokumasu, Taku Ohara, Gota Kikugawa

JOURNAL OF CHEMICAL PHYSICS　135　(13)　2011年10月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.3644938 　

ISSN：0021-9606

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Energy is commonly dissipated in molecular dynamics simulations by using a thermostat. In non-isothermal shear simulations of confined liquids, the choice of the thermostat is very delicate. We show in this paper that under certain conditions, the use of classical thermostats can lead to an erroneous description of the dynamics in the confined system. This occurs when a critical shear rate is surpassed as the thermo-viscous effects become prominent. In this high-shear-high-dissipation regime, advanced dissipation methods including a novel one are introduced and compared. The MD results show that the physical modeling of both the accommodation of the surface temperature to liquid heating and the heat conduction through the confining solids is essential. The novel method offers several advantages on existing ones including computational efficiency and easiness of application for complex systems. (C) 2011 American Institute of Physics. [doi:10.1063/1.3644938]
Heat conduction in chain polymer liquids: Molecular dynamics study on the contributions of inter- and intramolecular energy transfer

Taku Ohara, Tan Chia Yuan, Daichi Torii, Gota Kikugawa, Naohiro Kosugi

JOURNAL OF CHEMICAL PHYSICS　135　(3)　2011年7月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.3613648 　

ISSN：0021-9606

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In this paper, the molecular mechanisms which determine the thermal conductivity of long chain polymer liquids are discussed, based on the results observed in molecular dynamics simulations. Linear n-alkanes, which are typical polymer molecules, were chosen as the target of our studies. Non-equilibrium molecular dynamics simulations of bulk liquid n-alkanes under a constant temperature gradient were performed. Saturated liquids of n-alkanes with six different chain lengths were examined at the same reduced temperature (0.7T(c)), and the contributions of inter- and intramolecular energy transfer to heat conduction flux, which were identified as components of heat flux by the authors' previous study [J. Chem. Phys. 128, 044504 (2008)], were observed. The present study compared n-alkane liquids with various molecular lengths at the same reduced temperature and corresponding saturated densities, and found that the contribution of intramolecular energy transfer to the total heat flux, relative to that of intermolecular energy transfer, increased with the molecular length. The study revealed that in long chain polymer liquids, thermal energy is mainly transferred in the space along the stiff intramolecular bonds. This finding implies a connection between anisotropic thermal conductivity and the orientation of molecules in various organized structures with long polymer molecules aligned in a certain direction, which includes confined polymer liquids and self-organized structures such as membranes of amphiphilic molecules in water. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3613648]
A MOLECULAR DYNAMICS STUDY ON HEAT TRANSFER CHARACTERISTICS OVER THE INTERFACE OF SELF-ASSEMBLED MONOLAYER AND WATER SOLVENT

Gota Kikugawa, Taku Ohara, Toru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 3　405-+　2011年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS

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We performed molecular dynamics simulations of the interface which is comprised of self-assembled monolayer (SAM) and water solvent to investigate heat transfer characteristics. In particular, local thermal boundary conductance (TBC), which is an inverse of so-called Kapitza resistance, at the SAM solvent interface was evaluated by using the nonequilibrium MD (NEMD) technique in which the one-dimensional thermal energy flux was imposed across the interface. By using two kinds of SAM terminal with hydrophobic and hydrophilic properties, the local TBCs of these interfaces with water solvent were evaluated, and the result showed a critical difference due to an affinity between SAM and solvent. In order to elucidate the reason for this difference, microscopic components contributing to thermal energy flux across the interface were evaluated in detail, i.e., the total thermal energy flux is decomposed into the contribution of molecular transport and that of energy exchange by molecular interactions.
EFFECT OF ALKYL CHAIN LENGTH ON MOLECULAR HEAT TRANSFER CHARACTERISTICS IN LIPID BILAYERS

Takeo Nakano, Gota Kikugawa, Taku Ohara

PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 3　397-403　2011年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS

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Nonequilibrium molecular dynamics simulations are carried out on single component lipid bilayers with ambient water in order to investigate the effect of acyl chain length on heat transport characteristics along and across the membranes. In this study, dipalmitoyl-phosphatidyl-choline (DPPC), dilauroyl-phosphatidyl-choline (DLPC), and stearoyl-myristoyl-phosphatidyl-choline (SMPC) which has two acyl chains of both sixteen C atoms, both twelve C atoms, and eighteen and fourteen C atoms, respectively, were used as lipid molecules. In the direction along the membranes, thermal conductivity corresponds with that of each membrane. On the other hand, in the direction across membrane, the highest thermal resistance exists at the center of lipid bilayer where lipid acyl chains face each other However asymmetric chain length reduces thermal resistance at the interface between lipid monolayers. Therefore, thermal conductivity across the membrane which consists of asymmetric chain length is higher than those which consist of symmetric chain length.
GPUを用いた適応的粒子系可視化

小田川雅人, 竹島由里子, 藤代一成, 菊川豪太, 小原拓

日本機械学会論文集B編　77　(781)　1767-1778　2011年

DOI： 10.1299/kikaib.77.1767 　

ISSN：0387-5016
Momentum and Heat Transport in Nanoscale Lubrication of Alkane Thin Film Sheared by Self-Assembled Monolayer Surfaces

G. Kikugawa, N. Yamamoto, T. Ohara

Proceedings of the 4th International Conference on Heat Transfer and Fluid Flow in Microscale　2011年
Transport Phenomena at Nano-Structured Interfaces

M. Shibahara, T. Ohara, G. Kikugawa

Proceedings of the Eleventh International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　134-135　2011年
Interfacial Heat Transfer Characteristics over the Self-Assembled Monolayer and Solvent Interfaces

G. Kikugawa, T. Ohara, T. Kawaguchi, I. Kinefuchi, Y. Matsumoto

7th US-Japan Joint Seminar on Nanoscale Transport Phenomena - Science and Engineering -　44-44　2011年
Thickness uniformity of spin coated film influenced by nonuniform temperature of substrates

Taku Ohara, Shinichiro Matsubara, Hirotoshi Kadowaki, Gota Kikugawa, Kazuhiro Takeshita, Tomoko Hamada

International Journal of Emerging Multidisciplinary Fluid Sciences　2　(4)　215-232　2010年12月1日

DOI： 10.1260/1756-8315.2.4.215 　

ISSN：1756-8315

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The film thinning process in the spin coating has been analyzed by finite difference computational simulations. The coating liquid was assumed to be a solution of polymer solute and volatile organic solvent, for which Newtonian viscosity was given as a function of solute concentration. The flow of the coating liquid film that covers the entire substrate surface was analyzed where heat and mass transfer due to evaporation of solvent and heating/cooling by the substrate surface were taken into consideration. The whole process until all the solvent evaporates off the coating liquid and a dry coating film of the solute is left on the substrate was solved, and then the final film thickness was determined. Especially, influences of nonuniform substrate temperature on the profile of the final film thickness have been focused, for which three dimensional computational simulations have been performed. The case where the substrate is at rest and coating is processed only by drying the liquid film after a certain amount of solution liquid is deposited has also been analyzed and it was found that the final film thickness is larger at the local region of substrate with a higher temperature, exhibiting somewhat complicated thickness profiles.
A molecular dynamics study on heat conduction characteristics in DPPC lipid bilayer

Takeo Nakano, Gota Kikugawa, Taku Ohara

JOURNAL OF CHEMICAL PHYSICS　133　(15)　2010年10月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.3481650 　

ISSN：0021-9606

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In this paper, nonequilibrium molecular dynamics simulations were performed on a single component 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine lipid bilayer in order to investigate the thermal conductivity and its anisotropy. To evaluate the thermal conductivity, we applied a constant heat flux to the lipid bilayer along and across the membrane with ambient water. The contribution of molecular interaction to the heat conduction was also evaluated. Along the bilayer plane, there is little transfer of thermal energy by the interaction between lipid molecules as compared with the interaction between water molecules. Across the bilayer plane, the local thermal conductivity depends on the constituents (i.e., water, head group, and tail group of lipid molecule) that occupy the domain. Although the intramolecular transfer of thermal energy in the tail groups of lipid molecules works efficiently to promote high local thermal conductivity in this region, the highest thermal resistance appears at the center of lipid bilayer where acyl chains of lipid molecules face each other due to a loss of covalent-bond and low number density. The overall thermal conductivities of the lipid bilayer in the directions parallel and perpendicular to the lipid membrane have been compared, and it was found that the thermal conductivity normal to the membrane is higher than that along the membrane, but it is still smaller than that of bulk water. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3481650]
自己組織化単分子膜のための粒子配置設計支援システム招待有り

竹島由里子, 新坂拓真, 菊川豪太, 小原拓, 藤代一成

第38回可視化情報シンポジウム講演論文集　30　(1)　277-280　2010年7月21日
出版者・発行元：可視化情報学会
ISSN：0916-4731
T0501-1-2 酸化物固体-溶媒界面における溶質移動に関する2次元自由エネルギー曲面([T0501-1]マイクロ・ナノスケールの熱流体現象(1))

菊川豪太, 加藤惇平, 小原拓

年次大会講演論文集　2010　71-72　2010年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2010.8.0_71 　

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In this paper, we investigated mass transfer of Fe^<2+> ions adjacent to the magnetite (Fe_3O_4) solid surface from the microscopic viewpoint by using the molecular dynamic simulations. Not only mass transfer characteristic across the interface, but also that along the interface has to be elucidated in order to predict the strict transport path and diffusion process of ions in the vicinity of the interface. Therefore, we here evaluated two-dimensional free energy surface along the interface according to the ion translation. With Fe^<2+> ions fixed at a certain surface separation distance (SSD), the umbrella sampling/WHAM (weighted histogram analysis method) procedure which can be applied to two-dimensional space was adopted for free energy calculations. As a result, it was found that the free energy surface is significantly influenced by the surface charge distribution of the magnetite surface.
T0501-1-1 自己組織化膜修飾が固液界面熱抵抗に与える諸影響の分子論的解析([T0501-1]マイクロ・ナノスケールの熱流体現象(1))

川口暢, 菊川豪太, 杵淵郁也, 八束真一, 小原拓, 松本洋一郎

年次大会講演論文集　2010　69-70　2010年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2010.8.0_69 　

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We studied the influential factors on heat transfer at Au-toluene interface modified by dodecanethiol self-assembled monolayer (SAM). The thermal boundary conductance was calculated for different temperatures using nonequilibrium molecular dynamics simulation. As a result, the overall thermal boundary conductance at Au-SAM-toluene interface decreases as the temperature increases. We analyzed the temperature dependence of SAM structure and discussed the relation between SAM structure and thermal boundary conductance.
T0501-2-1 せん断流中における脂質二重膜の運動量伝搬特性に関する分子動力学的研究([T0501-2]マイクロ・ナノスケールの熱流体現象(2))

中野雄大, 菊川豪太, 小原拓

年次大会講演論文集　2010　81-82　2010年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2010.8.0_81 　

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Nonequilibrium molecular dynamics simulations were conducted for lipid bilayers with ambient water under two directions of shear flow along the bilayer plane to investigate mechanisms of momentum transfer characteristics in the membranes. Under a shear flow parallel to the bilayer plane, intermolecular interaction contributes to momentum flux positively in the lipid tail area, while negative flux due to intramolecular interaction arises. In the lipid head area, positive and negative contributions of each interaction invert. Under a shear flow perpendicular to the bilayer plane, the largest fraction to total momentum flux in the lipid bilayer is in the lipid head groups. This indicates that the contribution of the head group is the most dominant to surface shear viscosity in the lipid bilayer.
MOLECULAR DYNAMICS STUDY OF INTERFACIAL THERMAL RESISTANCE OF MERCAPTO-ALKANOL SELF-ASSEMBLED MONOLAYER AND WATER

Touru Kawaguchi, Gota Kikugawa, Ikuya Kinefuchi, Taku Ohara, Shinichi Yatuzuka, Yoichiro Matsumoto

MNHMT2009, VOL 2　217-221　2010年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS

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The interfacial thermal resistance of 11-mercaptoundecanol (-S(CH2)(11)OH) self-assembled monolayer (SAM) adsorbed on Au(111) substrate and water was investigated using nonequilibrium molecular dynamics simulations. The interfacial thermal resistance was found to be a half of that in the system which consists of 1-dodecanthiol (-S(CH2)(11)CH3) SAM adsorbed on Au(111) and toluene [Kikugawa G. et al., J. Chem. Phys. (2009)]. The effective thermal energy transfer originates from hydrogen-bond structure between the SAM and water molecules in spite of weak structurization of water molecules near the SAM surface.
Heat Transfer Characteristics at the SAM Interface with Water and Alkane Solvents

Gota Kikugawa, Taku Ohara, Toru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

Proceedings of Joint International Symposia on 3rd Micro & Nano Technology and Micro/Nanoscale Energy Conversion & Transport - 2010　116-118　2010年
長鎖ポリマー液体の熱伝導率：分子間及び分子内エネルギー伝搬の寄与についての分子動力学的研究

タンチアユアン, 鳥居大地, 小杉直央, 菊川豪太, 小原拓

熱物性　24　(3)　134-140　2010年
出版者・発行元：JAPAN SOCIETY OF THERMOPHYSICAL PROPERTIES
DOI： 10.2963/jjtp.24.134 　

ISSN：0913-946X

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長鎖状ポリマー分子からなる液体中の熱伝導を決定する分子スケールのメカニズムについて，分子動力学シミュレーションによる観察結果に基づいて議論する．典型的なポリマー分子として直鎖アルカンを選択し，そのバルク液体に一定の温度勾配及び熱流束を誘起させる非平衡分子動力学シミュレーションを行った．鎖長が異なる6種類の直鎖アルカン分子からなる対臨界温度0.7の飽和液を対象として，熱流束の構成要素である分子間・分子内相互作用によるエネルギー伝搬の大きさを観測した．その結果，分子の鎖長が長いほど，分子内エネルギー伝搬がなす寄与が分子間エネルギー伝搬と比較して大きくなり，長鎖ポリマー液体中では分子内の強固な結合に沿った熱エネルギーの空間中の移動が熱伝導流束を構成する主な因子であることが明らかになった．
非平衡分子動力学法を用いた親水性末端基を有する自己組織化膜と水の界面熱抵抗の解析

川口暢, 菊川豪太, 杵淵郁也, 八束真一, 小原拓, 松本洋一郎

日本機械学会論文集C編　76　(768)　1936-1938　2010年
出版者・発行元：None
DOI： 10.1299/kikaic.76.1936 　

ISSN：0387-5024
Heat Transfer Characteristics at the SAM Interface of Self-Assembled Monolayer with Hydrophobic and Hydrophilic Termini and Solvent

G. Kikugawa, T. Ohara, T. Kawaguchi, I. Kinefuchi, Y. Matsumoto

Proc. 7th International Conference on Flow Dynamics　370-371　2010年
Molecular Momentun Transfer Characteristics of Liquid Behaviors in Shear Flows

T. Nakano, G. Kikugawa, T. Ohara

Proc. 7th International Conference on Flow Dynamics　368-369　2010年
Assesment of Different Thermostating Techniques in the Simulation of Molecular Lubrication

H. Berro, T. Tokumasu, T. Ohara, G. Kikugawa, N. Fillot, P. Vergne

Proceedings of the 10th International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　128-129　2010年
Membrane Attachment Facilitates Ligand Access to the Active Site in Monoamine Oxidase A

Rossen Apostolov, Yasushige Yonezawa, Daron M. Standley, Gota Kikugawa, Yu Takano, Haruki Nakamura

BIOCHEMISTRY　48　(25)　5864-5873　2009年6月
出版者・発行元：AMER CHEMICAL SOC
DOI： 10.1021/bi900493n 　

ISSN：0006-2960

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Monoamine oxidase membrane enzymes are responsible for the catalytic breakdown of extra-and intracellular neurotransmitters and are targets for the development of central nervous system drugs. We analyzed the dynamics of rat MAOA by performing multiple independent molecular dynamics simulations of membrane-bound and membrane-free forms to clarify the relationship between the mechanics of the enzyme and its function, with particular emphasis on the significance of membrane attachment. Principal component analysis of the simulation trajectories as well as correlations in the fluctuations of the residues pointed to the existence of three domains that define the global dynamics of the protein. Interdomain anticorrelated movements in the membrane-bound system facilitated the relaxation of interactions between residues surrounding the substrate cavity and induced conformational changes which expanded the active site cavity and opened putative pathways for substrate uptake and product release. Such events were less pronounced in the membrane-free system due to differences in the nature of the dominant modes of motion. The presence of the lipid environment is suggested to assist in decoupling the interdomain motions, consistent with the observed reduction in enzyme activity under membrane-free conditions. Our results are also in accordance with mutational analysis which shows that modifications of interdomain hinge residues decrease the activity of rat MAOA in solution.
A molecular dynamics study on heat transfer characteristics at the interfaces of alkanethiolate self-assembled monolayer and organic solvent

Gota Kikugawa, Taku Ohara, Toru Kawaguchi, Eiichi Torigoe, Yasumasa Hagiwara, Yoichiro Matsumoto

JOURNAL OF CHEMICAL PHYSICS　130　(7)　2009年2月
出版者・発行元：AMER INST PHYSICS
DOI： 10.1063/1.3077315 　

ISSN：0021-9606

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In this paper, we present molecular dynamics (MD) simulations of interfaces composed of self-assembled monolayers (SAMs) and solvents in order to investigate the heat transfer characteristics at the interface. Two typical normal alkylthiolate SAMs with different chain lengths, i.e., 1-propanethiol C(3)H(7)SH and 1-dodecanethiol (C(12)H(25)SH) chemically adsorbed on Au(111) substrate surfaces, were used, and toluene was adopted as the organic solvent. In addition to the SAM systems, an interface composed of the bare solid substrate and solvent (without SAMs) was analyzed for comparison. Nonequilibrium MD simulations, in which a temperature gradient perpendicular to the interface was imposed, were performed and the difference in thermal boundary resistance in the interface systems was discussed. We observed that the SAM interfaces have smaller thermal resistance when compared with that of the bare solid interface. In order to understand the mechanisms of the small resistance at the SAM-solvent interfaces, the vibrational character of molecules in each phase, which contacted each other at the interface was analyzed and a detailed adsorbed structure of solvent molecule in the interface region was extracted. As a result, a clear difference in these characters was found between the SAM interfaces and bare solid interface.
T0501-1-5 ポリマー液体の熱輸送特性に及ぼす分子内エネルギー伝搬の影響(マイクロ・ナノスケールの熱流体現象(1))

タンチアユアン, 小杉直央, 鳥居大地, 菊川豪太, 小原拓

年次大会講演論文集　2009　103-104　2009年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2009.8.0_103 　

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Molecular dynamics simulations have been performed to investigate the effects of intramolecular energy transfer on heat conduction characteristics in bulk liquids of n-alkanes with several chain lengths. A simulation system which consists of a rectangular basic cell, where the periodic boundary condition is applied in all directions, is filled with n-alkane molecules. Artificially 'hot' and 'cold' slabs are placed at the middle and at both sides of the cell to generate constant heat energy flux in the system. Contributions of molecular motion and molecular interaction to thermal energy flux are measured in detail by applying a mathematical expression for thermal energy flux in molecular dynamic system which is extended to many-body potentials. The results show that the contribution of intramolecular energy transfer to the total thermal energy flux in n-alkane liquids increases with the extension of the molecular length when compared at the same reduced temperature and the saturation densities.
T0501-4-3 コーティング液膜流れの3次元数値解析(マイクロ・ナノスケールの熱流体現象(4))

門脇宏宗, 松原慎一郎, 菊川豪太, 小原拓

年次大会講演論文集　2009　135-136　2009年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2009.8.0_135 　

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The transient process of a liquid film flow that covers a rotating substrate in the spin coating process was analyzed by a 3-D computational simulation using the finite difference method. Evaporation of solvent and change of thermophysical properties such as viscosity was taken into account The case of nonuniform temperature distribution of the substrate was analyzed applying ring-like and spot-like high temperature region on the substrate, and it was concluded that hot ring/spot on the substrate results in large final film thickness on those ring/spot. As a special case of the spin coating, the drying process of the coating liquid on a substrate that was not rotating was also simulated, and it was found that the hot range on the substrate produces complicated profiles of the final film thickness.
T0501-1-3 固体表面近傍の水中における物質輸送特性(マイクロ・ナノスケールの熱流体現象(1))

加藤惇平, 菊川豪太, 小原拓, チアユアンタン

年次大会講演論文集　2009　99-100　2009年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2009.8.0_99 　

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Molecular dynamics simulations of the magnetite-water interface with eluted ions(Fe^<2+>, Fe(OH)_2 ) were performed in order to estimate free energy profile of the ions across the interface. The purpose of examining the free energy profile is to discuss mass transfer characteristics in the vicinity of interface. The free energy profile was calculated by using the umbrella sampling and WHAM procedure. From the calculation, we show that in the case of Fe^<2+> ion, a high free energy barrier exist at the solvent surface. On the other hand, in the case of Fe(OH)_2, the free energy barrier is not recognized because the strong coulomb interaction between hydroxyl group of Fe(OH)_2 and the magnetite surface contributes decrease of the energy barrier.
T0501-1-6 SAM内部およびSAM界面における熱輸送特性の分子動力学的研究(マイクロ・ナノスケールの熱流体現象(1))

菊川豪太, 持丸孝人, 小原拓, 川口暢, 松本洋一郎

年次大会講演論文集　2009　105-106　2009年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2009.8.0_105 　

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In this paper, we focused on heat transfer characteristics in the self-assembled monolayer (SAM) system with elucidating the dominant contribution of the molecular interactions to the heat transfer in each constituent phase, i.e., the alkanethiolate SAM phase, the interface of SAM and solvent, and alkane solvent phase. By using direct nonequilibrium molecular dynamics simulations, in which the temperature gradient was imposed across the SAM interface, each component of heat flux vector, which is transferred by molecular interactions including intra- and intermolecular interactions, were separately measured. Moreover, in order to investigate the effect of the SAM modification on thermal boundary resistance of the solid-liquid interface, the bare solid interface without the SAM was examined as well. As a result, the thermal boundary resistance at the SAM interface is much lower than that at the bare solid interface.
T0501-1-2 せん断流動場における脂質二重膜の運動量輸送特性の異方性に関する分子動力学的研究(マイクロ・ナノスケールの熱流体現象(1))

中野雄大, 菊川豪太, 小原拓

年次大会講演論文集　2009　97-98　2009年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2009.8.0_97 　

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Nonequilibrium molecular dynamics simulations were performed for lipid bilayers with ambient water under two shear flows along the bilayer plane to investigate mechanisms of heat generation and momentum transfer characteristics in the membranes. Under parallel shear flow to the bilayer, temperature rises by viscous heating in water layer and by frictional heating at the interface between two lipid monolayers. In the lipid tail area, intermolecular interaction contributes to momentum flux positively, while negative flux due to intramolecular interaction arises. In the lipid head area, positive and negative contributions of each interaction inverts. Under perpendicular shear flow to the bilayer, temperature of lipid is higher than that of water because of the difference of heat production by viscous heating and thermal conductivity. Momentum is dominantly transferred by intra- and intermolecular interaction between lipids. From the both simulations, friction coefficient at the interface of lipid acyl chains and surface shear viscosity of lipid are evaluated.
Application of MDGRAPE-3, a Special Purpose Board for Molecular Dynamics Simulations, to Periodic Biomolecular Systems

Gota Kikugawa, Rossen Apostolov, Narutoshi Kamiya, Makoto Taiji, Ryutaro Himeno, Haruki Nakamura, Yasushige Yonezawa

JOURNAL OF COMPUTATIONAL CHEMISTRY　30　(1)　110-118　2009年1月
出版者・発行元：JOHN WILEY & SONS INC
DOI： 10.1002/jcc.21035 　

ISSN：0192-8651

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We describe the application of a special purpose board for molecular dynamics simulations, named MDGRAPE-3, to the problem of simulating periodic bio-molecular systems. MDGRAPE-3 is the latest board in a series of hardware accelerators designed to calculate the nonbonding long-range interactions much more rapidly than normal processors. So far, MDGRAPEs were mainly applied to isolated systems, where very many nonbonded interactions were calculated without any distance cutoff. However, in order to regulate the density and pressure during simulations of membrane embedded protein systems, one has to evaluate interactions under periodic boundary conditions. For this purpose, we implemented the Particle-Mesh Ewald (PME) method, and its approximation with distance cutoffs and charge neutrality as proposed by Wolf et al., using MDGRAPE-3. When the two methods were applied to simulations of two periodic biomolecular systems, a single MDGRAPE-3 achieved 30-40 times faster computation times than a single conventional processor did in the both cases. Both methods are shown to have the same molecular structures and dynamics of the systems. (C) 2008 Wiley Periodicals, Inc. J Comput Chem 30: 110-118, 2009
SAM-溶媒界面の界面熱抵抗に関する分子動力学的研究

菊川豪太, 小原拓, 川口暢, 鳥越栄一, 萩原康正, 松本洋一郎

日本機械学会論文集B　75　(749)　146-154　2009年
出版者・発行元：日本機械学会
DOI： 10.1299/kikaib.75.749_146 　

ISSN：0387-5016

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In this paper, we perform molecular dynamics (MD) simulations of the interfaces composed of the self-assembled monolayer (SAM) and organic solvent in order to investigate the interfacial heat transfer characteristics of SAMs from the microscopic viewpoint. Archetypal SAMs, i.e., alkanethiol molecules chemically adsorbed on Au (111) substrate, and toluene solvent are adopted for the computational system. Two alkanethiols with different chain lengths, that is, 1-propanethiol (C_3H_7SH) and 1-dodecanethiol (C_<12>H_<25>SH), are used for SAM interface systems. In addition to the SAM interfaces, bare solid substrate without SAM are examined for comparison of the heat transfer characteristics. Nonequilibrium MD (NEMD) simulations in which a temperature gradient is imposed across the interface are performed and the interfacial thermal resistance in each system is discussed. As a result, it is shown that the SAM-solvent interfaces have the smaller thermal resistance as compared with that at the bare Au interface. In order to investigate the mechanisms of the small resistance at SAM-solvent interface, a vibrational character of molecules in the interface region and an adsorbed structure of solvent molecules are discussed.
The Effect of Different Thermostating Techniques on Friction and Dissipation in Molecular Dynamics Simulations of Confined Lubrication Films

Hassan Berro, Nicoas Fillot, Philippe Vergne, Takashi Tokumasu, Taku Ohara, Gota Kikugawa

Proc. of the World Tribology Congress 2009　622　2009年
A molecular dynamics Study on lipid bilayers in shear flows

Takeo Nakano, Gota Kikugawa, Taku Ohara

Proceedings of 2nd Asian Symposium on Computational Heat Transfer and Fluid Flow, Jeju　200-224　2009年
Heat transfer characteristics inside the SAM layer and at the SAM interfaces with organic solvents

Gota Kikugawa, Takato Mochimaru, Taku Ohara, Toru Kawaguchi, Yoichiro Matsumoto

Proceedings of 2nd Asian Symposium on Computational Heat Transfer and Fluid Flow, Jeju　2　225-229　2009年
Heat Transfer Characteristics inside the SAM layer and at the SAM interface

Gota Kikugawa, Taku Ohara, Toru Kawaguchi, Ikuya Kinefuchi, Yoichiro Matsumoto

Proc. 6th International Conference on Flow Dynamics　534-535　2009年
Thermal energy transfer in liquids with ordered/random structures

Taku Ohara, Gota Kikugawa

Proc. 6th International Conference on Flow Dynamics, Sendai　578　2009年
Transport Phenomena at Nano-Structured Interfaces

Taku Ohara, Masahiko Shibahara, Gota Kikugawa

Proc. 9th International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration, Sendai　82-83　2009年
505 アルカン液体の固液界面におけるエネルギー・運動量伝搬特性(T07-1 流体及び界面におけるナノ構造と流動特性(1),大会テーマセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

タンチアユアン, 鳥居大地, 菊川豪太, 小原拓

年次大会講演論文集　2008　209-210　2008年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2008.8.0_209 　

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Molecular dynamics simulations have been performed on ultra-thin liquid film which is sheared between two solid surfaces to clarify the mechanisms and characteristics of momentum and thermal energy transfer at solid-liquid interface. Four types of crystal plane of FCC lattice were examined for the surface of platinum solid wall and four types of n-alkane were employed as liquid. It was found that transfer characteristics of thermal energy and momentum at the solid-liquid interfaces were significantly influenced by the types of crystal plane of the solid surface and the length of the n-alkanes.
507 SAM-溶媒界面における界面熱抵抗特性の分子論的研究(T07-2 流体及び界面におけるナノ構造と流動特性(2),大会テーマセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

菊川豪太, 小原拓, 川口暢, 鳥越栄一, 萩原康正, 松本洋一郎

年次大会講演論文集　2008　213-214　2008年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2008.8.0_213 　

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In this paper, we perform molecular dynamics simulations of self-assembled monolayer (SAM) and solvent interfaces in order to elucidate the microscopic mechanisms of interfacial heat transfer at the SAM interfaces. Archetypal SAM systems, i.e., n-alkanethiol chemically adsorbed on Au (111), and toluene solvent are employed in our simulations. By using nonequilibrium molecular dynamics technique, a temperature gradient is imposed perpendicular to the interface, and interfacial heat transfer characteristics are analyzed. In addition to the SAM systems, a bare solid substrate and solvent system is examined to compare thermal boundary resistances at the SAM-modified interface and non-modified one. As a result, we find a significant decrease of the thermal boundary resistance at the SAM-toluene interface as compared to that of the bare Au interface. In order to explain this effect, we focus on the adsorption structure of toluene in the vicinity of the interface.
A Molecular Dynamics Study on the Local Structure of Liquid-Vapor Interface of Water and L-J Fluid

Gota Kikugawa, Shu Takagi, Yoichiro Matsumoto, Taku Ohara

JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY　3　(2)　234-240　2008年
出版者・発行元：JAPAN SOC MECHANICAL ENGINEERS
DOI： 10.1299/jtst.3.234 　

ISSN：1880-5566

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Microscopic structures of a liquid-vapor interface are investigated by molecular dynamics simulations. In the previous studies, we proposed the local and instantaneous definition of the interface at the molecular level, which can capture the thermal fluctuation of the interface. By using this definition, the layering structure of water molecules at the interface was found, in other words, the structurization phenomena of water at the molecular level were clearly seen as usually found at the liquid-solid interface. In this study, we investigated the liquid-vapor interface of Lenard-Jones fluid. The effect of well depth of L-J potential parameter on the structure was also studied. Although the structurization was found at the L-J fluid as well as water, characteristic of this structure was clearly different from that of water. We consider that the difference is ascribed to the intrinsic structure of liquid and associative trend of molecules. We also discussed the anisotropic characteristics of the molecular diffusion at the interface. The anisotropy of the translational diffusion at the interface of water is stronger than that of the L-J fluid.
Study on Molecular Thermal Energy Transfer in a Lipid Bilayer

Takeo Nakano, Taku Ohara, Gota Kikugawa

JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY　3　(3)　421-429　2008年
出版者・発行元：JAPAN SOC MECHANICAL ENGINEERS
DOI： 10.1299/jtst.3.421 　

ISSN：1880-5566

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Recently, lipid bilayers attract a great deal of interest as a material with nanoscale structure. Various devices utilizing lipid bilayers, which include some kinds of sensors and molecular sorting devices, have been proposed. Understanding of thermal energy transfer in the lipid bilayers is important for utilizing the lipid bilayers as a new material for NEMS with nano structures. In this study, we have investigated the energy transfer along and across the bilayer membrane by molecular dynamics simulations of the lipid bilayer in liquid water. We found that along the bilayer membrane, thermal energy flux in the lipid bilayer is much smaller than that in the water layer. On the other hand, in case of thermal energy transfer across the membrane, total thermal resistance of the lipid bilayer-water system is composed of thermal resistances of various parts of the system, including water layer, head group of lipid, and tail hydrocarbon chain of lipid, which exhibit different magnitude of values. It is found that the tail hydrocarbon chains of lipid have the highest thermal resistance.
A molecular dynamics study on heat conduction characteristics in lipid bilayer

T. Nakano, G. Kikugawa, T. Ohara

Proc. The Second International Forum on Heat Transfer　112-112　2008年
A molecular dynamics study on the heat transfer characteristics at a SAM-solvent interface

G. Kikugawa, T. Kawaguchi, T. Ohara, E. Torigoe, Y. Hagiwara, Y. Matsumoto

Proc. The Second International Forum on Heat Transfer　110-110　2008年
Molecyular dynamics study on lipid-bilayer membranes in shear flow

T. Nakano, G. Kikugawa, T. Ohara

Proc. The Seventh JSME-KSME Thermal and Fluids Engineering Conference　2008年
Thermal boundary resistance at the interface of self-assembled monolayers

G. Kikugawa, T. Kawaguchi, T. Ohara, E. Torigoe, Y. Hagiwara, Y. Matsumoto

Proc. The Seventh JSME-KSME Thermal and Fluids Engineering Conference, Sapporo　2008年
A molecular dynamics study on heat transfer characteristics in lipid membranes

T. Nakano, G. Kikugawa, T. Ohara

Proc. The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年
Interfacial heat transfer characteristics at the interface of self-assembled monolayers and organic solvent

G. Kikugawa, T. Ohara, T. Kawaguchi, E. Torigoe, Y. Hagiwara, Y. Matsumoto

Proc. The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年
Point sprite-based visualization of large-scale particle systems

M. Odagawa, Y. Takeshima, I. Fujishiro, G. Kikugawa, T. Ohara, Y. Terada, M. Tokuyama

Proc. The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年
ミクロスケールにおける気液界面の局所・瞬時的定義について

菊川豪太, 高木周, 松本洋一郎

日本機械学会論文集B　73　(725)　118-125　2007年

DOI： 10.1299/kikaib.73.118 　
A molecular dynamics study on liquid-vapor interface adsorbed by impurities

Gota Kikugawa, Shu Takagi, Yoichiro Matsumoto

COMPUTERS & FLUIDS　36　(1)　69-76　2007年1月
出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD
DOI： 10.1016/j.compfluid.2005.07.007 　

ISSN：0045-7930

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in this paper, we focus on the microscopic structure of the liquid-vapor interface and the effect of impurities such as surfactants or electrolytes in the aqueous solution on interfacial properties. We perform molecular dynamics (MD) simulations of a simple planar interface system and a bubble system in which a nanometer-size void region is maintained. In these MD systems, some static and dynamic properties of molecules near the interface are investigated and we elucidate some microscopic features of the interface. Especially, we show the difference of the dynamics of water molecules between the surfactant and electrolyte solutions. We also consider the definition of the interface at the molecular level which can treat the local and instantaneous structure, and discuss the physical properties which we calculate including the effect of molecular fluctuations of the interface. (c) 2005 Published by Elsevier Ltd.
A molecular dynamics study on the local structure of liquid-vapor interface of water and L-J fluid

Gota Kikugawa, Shu Takagi, Yoichiro Matsumoto, Taku Ohara

PROCEEDINGS OF THE ASME/JSME THERMAL ENGINEERING SUMMER HEAT TRANSFER CONFERENCE 2007, VOL 1　91-96　2007年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS
DOI： 10.1115/HT2007-32722 　

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Microscopic structures of the liquid-vapor interface are investigated by molecular dynamics simulations. In previous studies, we proposed the local and instantaneous definition of the interface at the molecular level, which can capture the thermal fluctuation of the interface. By using this definition, the layering structure of water molecules at the interface is found, in other words, the structurization phenomena of water at the molecular level are clearly seen as usually found at the liquid-solid interface. In this study, we also investigated the liquid-vapor interface of Lenard-Jones fluid. Well depth of L-J potential parameter was somewhat changed and the effect on the structure was studied. Although the structurization was also found at the L-J fluid as well as water, characteristic of this structure is clearly different from that of water. We consider that the difference is ascribed to the intrinsic structure of liquid and associative trend of molecules. We also discussed the anisotropic character of the molecular diffusion at the interface. The anisotropy of the translational diffusion at the interface of water is stronger than that of the L-J fluid.
Study on molecular thermal energy transfer in a lipid bilayer

Takeo Nakano, Taku Ohara, Gota Kikugawa

PROCEEDINGS OF THE ASME/JSME THERMAL ENGINEERING SUMMER HEAT TRANSFER CONFERENCE 2007, VOL 1　59-63　2007年
出版者・発行元：AMER SOC MECHANICAL ENGINEERS
DOI： 10.1115/HT2007-32635 　

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In recent studies, lipid bilayers attract a great deal of interest as a material for nanoscale structure. Some devices utilizing lipid bilayers, which include various kinds of sensors and molecular sorting devices, have been proposed. Understanding of thermal energy transfer in the lipid bilayers plays an important role in developing such devices with nano structures. In this study, we have investigated the energy transfer along and across the bilayer membrane by molecular dynamics simulations of the lipid bilayer in liquid water. We found that along the bilayer, the thermal energy is transferred by the interaction principally between water molecules and barely between lipid molecules. On the other hand, in the latter case, total thermal resistance of the lipid bilayer structure is composed of the thermal resistance of the structure's various parts, including water, head group of lipid, and tail hydrocarbon chain of lipid, which show different values. It is found that the tail hydrocarbon chains have the highest thermal resistance.
1P579 Large-scale molecular dynamics simulations with the pairwise electrostatic interaction method for protein-solvent systems(27. Molecular dynamics simulation,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)

Kikugawa Gota, Yonezawa Yasushige, Nakamura Haruki, Himeno Ryutaro

生物物理　46　(2)　S291　2006年
出版者・発行元：一般社団法人日本生物物理学会
DOI： 10.2142/biophys.46.S291_3 　
A novel definition of the local and instantaneous liquid-vapor interface 査読有り

Gota Kikugawa, Shu Takagi, Yoichiro Matsumoto

IUTAM SYMPOSIUM ON COMPUTATIONAL APPROACHES TO MULTIPHASE FLOW　81　131-+　2006年
出版者・発行元：SPRINGER

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In this paper, we present a new definition of liquid-vapor interface at the molecular level which can capture the local and instantaneous structure of the interface. The new definition is not a thermodynamic definition of the interface, such as the equimolar surface, but is based on the instantaneous particle density distribution of molecules. Applying the new definition of the interface to the MD result of the liquid-vapor interface, we found that our definition of the interface was able to capture the microscopic fluctuation caused by molecular motion. Furthermore, we confirmed that on the longtime average our definition of the interface shows good agreement with the equimolar surface.
A113 分子動力学シミュレーションにおける気液界面の定義について

高木周, 菊川豪太, 松本洋一郎

可視化情報学会誌　24　(1)　59-62　2004年
出版者・発行元：The Visualization Society of Japan
DOI： 10.3154/jvs.24.Supplement1_59 　

ISSN：0916-4731

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We present a novel definition of the local and instantaneous interface of the liquid-vapor equilibrium system from the microscopic point of view. In this definition, the density distribution, which is given by the position of discrete particles from molecular dynamics (MD) simulation, is described as the field quantity. In other words, we make the density distribution, which is inherently described by the summation of the delta functions, smoothed by distributing the smoothed delta function on the position of each molecule. The surface position is defined as the position on which the field has the certain density value, and the distance function from the surface can be evaluated by the reinitialization procedure of the level set method. In order to investigate the physical meaning of our proposed definition of the instantaneous interface, we calculated the averaged position of the instantaneous interface, and found that it shows a good agreement with the position of the equimolar surface which is defined thermodynamically in the Gibbs's manner.
1434 ナノバブルの局所界面構造に関する分子動力学解析

菊川豪太, 高木周, 松本洋一郎

年次大会講演論文集　2003　181-182　2003年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2003.6.0_181 　

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A molecular dynamics simulation of aqueous surfactant system is carried out to investigate the microscopic structure of gas-liquid interface. To analyze the interfacial structure which has the local fluctuation, we propose the new definition of interface which maintains the local and instantaneous information. After this method is applied to the interface of nanobubble, it was found that the bubble region did not hold its spherical shape instantaneously and its surface fluctuated locally. It was also found that the rotational relaxation time of water molecules at the bubble surface adsorbed by surfactants was longer than that of bulk liquid. So it can be though that water molecules near the interface are structurized by surfactants.
1519 界面活性剤によるナノバブルの安定化に関する分子動力学的解析

菊川豪太, 高木周, 松本洋一郎

年次大会講演論文集　2002　37-38　2002年
出版者・発行元：一般社団法人日本機械学会
DOI： 10.1299/jsmemecjo.2002.4.0_37 　

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A molecular dynamics simulation of an aqueous surfactant system : water liquid and alcohols below the liquid saturation density is carried out to investigate the stability of "nanobubbles" and the structure of the gas-liquid interface. To analyze the effect of the surfactant structure, volume, and polarization on the stability of bubble nuclei, we use TIP3P water as the solvent molecules and 1-propanol, 1-pentanol, 1-heptanol as the surfactant molecules. The intramolecular energy and motion of all molecules is taken into account, by applying the AMBER force field. Adding polarized surfactants to the metastable state of liquid in which bubble nuclei cannot exist stably, it is found that a stable bubble is formed and hydroxyl groups of surfactants tend to point to the liquid phase at the gas-liquid interface. It is also shown that the longer hydrophobic chains the surfactants have, the more stably the bubble nuclei can exist.

︎全件表示 ︎最初の5件までを表示

MISC 42

界面への有機分子修飾による熱伝導の促進とその分子設計査読有り

菊川豪太

化学と教育　69　524-527　2021年12月
自己組織化マップを用いた多目的材料設計

大矢豊大, 菊川豪太

日本接着学会誌　56　(11)　423-430　2020年11月1日
Molecular Dynamics Simulation with Reaction Model Based on Accurate Quantum Chemical Calculation for Cross-Linking Process of Epoxy Resins and its Comparison to Experimental Measurement

Yutaka Oya, Yuki Hino, Kyosuke Inuyama, Gota Kikugawa, Jing Li, Riichi Kuwahara, Naoki Kishimoto, Hiroki Waizumi, Masaaki Nishikawa, Anthony Waas, Nobuyuki Odagiri, Andrew Koyanagi, Marco Salviato, Tomonaga Okabe

2019年7月16日

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We propose a new simulation procedure for the curing reaction of epoxy resin by coupling quantum chemical (QC) calculations with molecular dynamics (MD) simulations. A polymer network formation composed of base resin and curing agent is investigated using the present simulation. Relationships between the atomistic structures in the system and their material properties derived from the simulations are also studied. The polymer network formation includes the reaction between epoxy resin and curing agents. Accurate activation energy and heat of formation are required for simulating the reaction. In this study, we introduce the ab initio QC calculation to the MD simulation to determine out the reaction pathways. To validate our proposed simulation, we experimentally measured densities, thermal characteristics and mechanical properties. The simulated results agree with experiments. The simulated results also indicate that branching structures of monomers causes the coarsening of the network formation of epoxy resin, so that the glass transition temperature (i.e. Tg) tends to increase. In contrast with Tg, the densities and Young's modulus are dominated mainly by the backbone structure of monomers and the degree of conversions.
閉じ込め液体系における自己拡散係数への有限サイズ効果

菊川豪太

アンサンブル　20　179-184　2018年7月
液体・界面の熱輸送特性発現機構 - 分子設計を志向して

松原裕樹, 菊川豪太, 小原拓

伝熱　56　(236)　17-24　2017年
出版者・発行元：日本伝熱学会
ISSN：1344-8692
101 フルオロカーボンSAM界面の熱輸送特性に関する分子動力学的研究

根本充, 菊川豪太, 別所毅, 山下征士, 小原拓

講演論文集　2016　(51)　3-4　2016年
出版者・発行元：一般社団法人日本機械学会
108 Molecular Thermal Energy Transfer in Binary Mixture of Simple Liquids

Fang Yingping, Kikugawa Gota, Matsubara Hiroki, Bessho Takeshi, Yamashita Seiji, Ohara Taku

講演論文集　2016　(51)　15-16　2016年
出版者・発行元：一般社団法人日本機械学会
C214 1-ブチル-3-メチルイミゾダリウム塩系イオン液体中の熱エネルギー伝搬機構に関する分子動力学シミュレーション(OS-13:分子シミュレーション(1))

羽田城司, 菊川豪太, 小原拓

熱工学コンファレンス講演論文集　2015　"C214-1"-"C214-2"　2015年10月23日
出版者・発行元：一般社団法人日本機械学会

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The molecular level mechanism of thermal energy transfer is important in thermal engineering or understanding the factors that determine macroscopic thermal conductivity, which enables design of thermal medium having desired thermophysical properties. This is a report of non-equilibrium molecular dynamics (MD)simulation of heat conduction in ionic liquids, which attract attentions in various engineering fieldsrecently. MD simulations were performed for 1-butyl-3-metyhlimidazolium ionic liquids at 323 K and 1×10^5 Pa by using the united atom model in three systems which have different size of anions (F^-, Cl^- and Br^-). Thecontributions of molecular migration and intra/intermolecular interactions to heat flux has been analyzed.
J0540304 壁面近傍のナノスケール液体における物質輸送特性

鈴木城, 菊川豪太, 中野雄大, 小原拓

年次大会 : Mechanical Engineering Congress, Japan　2015　"J0540304-1"-"J0540304-3"　2015年9月13日
出版者・発行元：一般社団法人日本機械学会

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Mass transport in ordered structures of a liquid which are formed in the vicinity of a solid-liquid interface exhibits decidedly different characteristics from the ordinary diffusion. Using the PMF (potential of mean force) profile obtained from the number density of liquid molecules, the kinetic process model to describe the molecular mobility inside these ordered structures was developed in this study. From the result obtained from molecular dynamics (MD) simulations, it was found that the developed kinetic model can accurately predict the molecular mobility over the free energy barrier.
熱流体工学における分子動力学シミュレーション

小原拓, 菊川豪太

アンサンブル分子シミュレーション研究会　17　(1)　35-43　2015年
出版者・発行元：分子シミュレーション研究会
DOI： 10.11436/mssj.17.35 　

ISSN：1884-6750

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機械工学において流体中の熱・物質輸送現象を解明しその応用を図るのが熱流体工学である．近年，この分野に分子動力学シミュレーションが取り入れられ，界面現象や熱物性値の研究に成果を上げている．分子熱流体と呼ばれるこの分野における研究を紹介するのが，本稿の目的である．
分子動力学計算系におけるバルク液体の自己拡散係数に対する計算系形状の影響

鈴木城, 菊川豪太, 安藤翔太郎, 成毛陽一, 小原拓

計算力学講演会講演論文集　2014　(27)　711-713　2014年11月22日
出版者・発行元：一般社団法人日本機械学会
ISSN：1348-026X

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In the present study, molecular dynamics (MD) simulations on simple liquids like monatomic Lennard-Jones and water bulk liquids in periodic boundary systems were performed to clarify the effect of the system size and shape on self-diffusion coefficient. So far, in the previous publications, the system size effect in cubic computational domains has been reported, and these studies showed that the diffusion coefficient becomes smaller as the system size decreases. Here we examined the system size effect not only in the cubic cell systems, but also in the rectangular cell systems which were created by changing one side length of the cubic cell with the system density kept constant. It is found that the diffusion coefficient in the direction perpendicular to the long side of the rectangular cell significantly increases more or less linearly as the side length increases for both liquids. On the other hand, the diffusion coefficient in the direction along the long side is almost constant. In consequence, anisotropy of the diffusivity appears in the rectangular cell with a periodic boundary condition even though the diffusion property of bulk liquids is examined.
分子動力学法による鎖状アルカン液体の熱伝導解析 : 分岐鎖の影響

松原裕樹, 菊川豪太, 別所毅, 山下征士, 小原拓

計算力学講演会講演論文集　2014　(27)　714-715　2014年11月22日
出版者・発行元：一般社団法人日本機械学会
ISSN：1348-026X

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This paper investigates how the details of molecular structure affect the thermal properties of liquids. We carried out the nonequilibrium molecular dynamics simulations for the liquids of a systematic series of branched-alkanes. In the simulations, the thermal conductivity as well as the corresponding heat flux were calculated. Particularly, the heat transfer by way of side chain was analyzed in detail. It is shown that the heat flux associated with one side chain atom is not significantly different for the different alkane species, and thus the total heat flux of side chain is proportional to the number density of side chain atoms.
B222 固液界面近傍におけるアルカン液体の局所的熱伝導率

チルコティハリクリシュナ, 菊川豪太, 小原拓

熱工学コンファレンス講演論文集　2014　"B222-1"-"B222-2"　2014年11月8日
出版者・発行元：一般社団法人日本機械学会

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In this paper, thermal conductivity of liquid n-alkanes in the vicinity of three crystal planes of a-quartz substrate terminated with H and OH-groups have been investigated using nonequilibrium molecular dynamics simulations. Methane and decane molecules are considered as alkane molecules in this study. It is found that the thermal conductivity fluctuates in an oscillating manner in the solid-liquid interface region. These fluctuations are typically in proportion to the oscillations in the density profile.
J0550304 Lennard-Jonesおよび水バルク液体の自己拡散係数に対する計算系形状の影響([J055-03]マイクロ・ナノスケール熱流体現象(3))

菊川豪太, 安藤翔太郎, 鈴木城, 成毛陽一, 中野雄大, 小原拓

年次大会 : Mechanical Engineering Congress, Japan　2014　"J0550304-1"-"J0550304-5"　2014年9月7日
出版者・発行元：一般社団法人日本機械学会

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In the present study, molecular dynamics (MD) simulations on monatomic Lennard-Jones and water bulk liquids in the periodic boundary system were performed in order to elucidate the effect of the system size and shape on self-diffusion coefficient. So far, the system size effect in cubic computational domains has been intensively investigated and these studies showed that the diffusion coefficient becomes smaller as the system size decreases. We examined the system size effect not only in the cubic cell systems, but also in the rectangular cell systems which were created by changing one side length of the cubic cell with the system density kept. As a result, the diffusion coefficient in the direction perpendicular to the longer side of the rectangular cell significantly increases more or less linearly as the side length increases for both liquids. On the other hand, the diffusion coefficient in the direction along the longer side is almost constant or slightly decreases. Consequently, anisotropy of diffusion coefficient appears in the rectangular cell with a periodic boundary condition even in the case of bulk liquids.
G131 SiO_2固体壁近傍における水およびIPAの物質輸送特性に関する分子動力学的研究(OS-7:マイクロ・ナノ熱工学(3))

成毛陽一, 小坂秀一, 中野雄大, 菊川豪太, 小原拓

熱工学コンファレンス講演論文集　2013　215-216　2013年10月18日
出版者・発行元：一般社団法人日本機械学会

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Mass transport in the vicinity of solid-liquid interfaces exhibits complicated characteristics and an essential understanding of their mechanism is of critical importance. The interfaces between SiO_2 and water or IPA (iso-propyl alcohol) are typical system in the semiconductor industry. In the present study, we investigated molecular-scale structures of the adsorption layers of liquid molecules and molecular transport characteristics by using molecular dynamics (MD) simulations in order to clarify the mass transport in the vicinity of the interfaces between SiO_2 and liquids. As typical terminations of SiO_2 surfaces, H- and OH- terminated ones were used and self-diffusion coefficients in the direction parallel to the interface were measured and the mass transfer properties were discussed.
J053013 架橋を有するアモルファスポリマー材料における熱輸送機構の解明(〔J053-01〕マイクロ・ナノスケールの熱流体現象(1))

菊川豪太, KEBLINSKI Pawel, 小原拓

年次大会 : Mechanical Engineering Congress, Japan　2013　"J053013-1"-"J053013-5"　2013年9月8日
出版者・発行元：一般社団法人日本機械学会

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In the present study, molecular dynamics (MD) simulations on two typical amorphous polymers, polyethylene (PE) and polystyrene (PS) were performed in order to elucidate the effect of crosslinks between polymer chains on heat conduction. Direct nonequilibrium MD techniques were used to evaluate thermal conductivities in both polymeric systems with varying a crosslink concentration. In the PE systems, the effect of crosslinking on thermal conductivity is significant and the thermal conductivity more or less linearly increases with the crosslink concentration. On the other hand, the change of thermal conductivity in the PS systems is insignificant. We guess that this striking difference is due to highly heterogeneous PS based network including phenyl side groups in terms of molecular interactions and molecular conformation. In order to elucidate the molecular-scale mechanism on the increase of thermal conductivity with the crosslink concentration for PE, we monitored microscopic energy transfer modes associated with various bonded and non-bonded interactions. The results show that crosslinking plays a role in creating new thermal paths to increase thermal conductivity.
日本伝熱学会学術賞を受賞して

中野雄大, 菊川豪太, 小原拓

伝熱 : journal of the Heat Transfer Society of Japan　52　(220)　6-6　2013年7月1日

ISSN：1344-8692
OS1-1-6 SiO_2-水/IPA界面近傍における液膜中の構造と物質輸送に対する温度の影響(OS1 マルチスケ-ル現象のシミュレーション技術(1))

中野雄大, 小坂秀一, 菊川豪太, 小原拓

マイクロ・ナノ工学シンポジウム　2012　(4)　129-130　2012年10月21日
出版者・発行元：一般社団法人日本機械学会

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Molecular dynamics simulations are performed in order to investigate an impact of temperature on molecular structure and mass transport properties in the vicinity of silica-water and/or iso-propyl alcohol (IPA) liquid film interfaces. Water and IPA liquid molecules form layer structure in the vicinity of the solid, respectively. Although temperature has an insignificant effect on the first layer from the solid, the layer structure at higher temperature decays farther away from the second layer comparing with lower temperature for both silica-water and silica-IPA systems. Moreover, interfusion of water and IPA molecules between silica substrates is simulated and coverage molecules on the substrates are analyzed for temperatures of 300K and 350K.
J053034 直鎖アルカン飽和液中の熱エネルギー伝搬機構に関するAll-Atom分子動力学シミュレーション

羽田城司, 菊川豪太, 小原拓

年次大会 : Mechanical Engineering Congress, Japan　2012　"J053034-1"-"J053034-3"　2012年9月9日
出版者・発行元：一般社団法人日本機械学会

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This report mentions non-equilibrium molecular dynamics (MD) simulation of heat conduction in alkane liquids. In the previous study, the authors have analyzed the molecular mechanism of heat conduction in liquid n-alkanes ofvarious molecular lengths by utilizing the united-atom model. Although the results were satisfactorily reasonable, the influence of C-H bonds was not clarified because the bonds were ignored in the united atom model. To analyze the influence, a non-equilibrium MD simulation was performed in the present study for heat conduction in liquid n-alkanes applying an all-atom model. The influence of the presence of H sites and the contributions of the C-H bond were examined.
日本熱物性学会賞論文賞を受賞して

小原拓, ユアンタンチア, 鳥居大地, 小杉直央, 菊川豪太

熱物性 : Japan journal of thermophysical properties　26　(1)　4-4　2012年2月29日

ISSN：0913-946X
G114 親水性および疎水性SAMと水溶媒の界面における熱輸送機構の詳細解析(一般講演(1))

菊川豪太, 小原拓, 川口暢, 杵淵郁也, 松本洋一郎

熱工学コンファレンス講演論文集　2011　159-160　2011年10月28日
出版者・発行元：一般社団法人日本機械学会

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In the present paper, molecular dynamics simulations of the interface system comprised of self-assembled monolayers (SAMs) and water solvent were performed in order to investigate heat transfer characteristics. Here we focused on the effect of hydrophobicity of SAMs on interfacial heat transfer. Two types of SAM terminal groups, i.e., methyl (CH3-) and hydroxyl (OH-) terminals which have hydrophobic and hydrophilic characters, respectively, were adopted. Nonequilibrium molecular dynamics simulations, in which a constant heat flux was imposed across the SAM interface, were performed to evaluate thermal boundary conductances (TBCs). The result demonstrated that the TBC at the OH-terminated SAM interface is one order of magnitude larger than that at the methyl-terminated SAM interface. Moreover, possible reasons for this significant difference were explored.
4-4 マグネタイト-水溶媒界面におけるイオン移動の自由エネルギー分布(セッション4:OS1-1 マルチスケール・シミュレーションとナノ計測)

菊川豪太, 加藤惇平, 小原拓

マイクロ・ナノ工学シンポジウム　2011　(3)　43-44　2011年9月25日
出版者・発行元：一般社団法人日本機械学会

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In the present paper, we investigated mass transfer characteristics of Fe^<2+> ions over the magnetite (Fe_3O_4) substrate/water solvent interface by using the molecular dynamics simulations. In addition to the transfer perpendicular to the interface, that along the interface has to be elucidated in order to understand the precise transport properties and diffusion process of ions in the vicinity of the interface with complicated surface structure. Therefore, we here evaluated two-dimensional free energy surface along the interface according to the ion translation with umbrella sampling/WHAM (weighted histogram analysis method) technique. Additionally, actual ion trajectories adjacent to the interface were traced to compare those with the probable transport paths predicted from the free energy surface. As a result, it was found that the free energy surface is significantly influenced by the surface charge distribution of the magnetite surface, and the trajectories show a good correlation with the free energy profiles.
B214 親水性および疎水性末端基を持つSAM-溶媒界面の熱輸送特性(OS-4:マイクロ・ナノ熱工学(III))

菊川豪太, 小原拓, 川口暢, 杵淵郁也, 松本洋一郎

熱工学コンファレンス講演論文集　2010　259-260　2010年10月29日
出版者・発行元：一般社団法人日本機械学会

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In this paper, we investigated the heat transfer characteristics over the interface of self-assembled monolayers (SAMs) and water solvent by using molecular dynamics simulations. Two types of SAM terminal groups, i.e., methyl (CH_3-) and hydroxyl (OH-) which have a hydrophobic and hydrophilic property, respectively, were applied to elucidate the effect of the affinity between the SAM and solvent. By nonequilibrium molecular dynamics simulations, a constant heat flux was imposed across the SAM interface and the resultant temperature distribution was obtained. Thereby, thermal boundary conductances (TBC) were evaluated at the both SAM interfaces. The result demonstrated that the TBC at the OH-terminated SAM interface is one order of magnitude larger than that at the methyl-terminated SAM interface.
MNM-5A-4 脂質二重膜の熱輸送特性に対するアルキル鎖界面の影響(セッション 5A ナノ・マイクロ異相界面センシングと制御)

中野雄大, 菊川豪太, 小原拓

マイクロ・ナノ工学シンポジウム　2010　(2)　201-202　2010年10月12日
出版者・発行元：一般社団法人日本機械学会

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Nonequilibrium molecular dynamics simulations are carried out on single component lipid bilayer membranes with ambient water in order to elucidate influence of alkyl chain length on characteristics of heat transfer along and across the membranes. It was found that thermal conductivity along membrane corresponds with that of each membrane despite different lipid species. On the other hand, in the direction perpendicular to the membrane, the highest thermal resistance exists at the center of lipid bilayer where lipid acyl chains face each other. However, asymmetric chain length increases interface thermal conductance at the center of lipid bilayer compared with symmetric chain length. Thereby, overall thermal conductivity of across the membrane which consists of asymmetric chain length is higher than that which consists of symmetric chain length.
MNM-5A-6 自己組織化単分子膜を修飾した固液界面における界面熱コンダクタンスの温度依存性の分子論的研究(セッション 5A ナノ・マイクロ異相界面センシングと制御)

川口暢, 杵淵郁也, 菊川豪太, 小原拓, 松本洋一郎

マイクロ・ナノ工学シンポジウム　2010　(2)　205-206　2010年10月12日
出版者・発行元：一般社団法人日本機械学会

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We studied influential factors in heat transfer characteristics at the Au-toluene interface modified by dodecanethiol self-assembled monolayer (SAM) using nonequilibrium molecular dynamics simulation. The thermal boundary conductances of Au-SAM-toluene interface for different temperature were evaluated. As a result, the overall thermal boundary conductance tends to decrease as the temperature increases. This is partly because the depth of the hollow on the SAM surface becomes small and the probability density of toluene at the hollow site becomes lower as the temperature increases.
日本伝熱学会奨励賞を受賞して

菊川豪太

伝熱 : journal of the Heat Transfer Society of Japan　49　(208)　9-9　2010年7月1日

ISSN：1344-8692
大規模粒子系の対話的可視化による分子配置に関するパラメータスタディ支援

新坂拓真, 竹島由里子, 菊川豪太, 小原拓, 藤代一成

情報処理学会第72回全国大会講演論文集　4　321-322　2010年3月9日
出版者・発行元：情報処理学会
脂質二重膜の熱輸送特性に対する脂質分子種の影響(分子スケール(3),一般講演)

中野雄大, 菊川豪太, 小原拓

日本流体力学会年会講演論文集　2010　111-111　2010年
出版者・発行元：日本流体力学会

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Nonequilibrium molecular dynamics simulations are performed on single component DPPC, DLPC, and SMPC lipid bilayer membranes with ambient water in order to investigate the effect of molecular species on heat transport characteristics along and across the membranes. Thermal conductivity along membrane corresponds with that of each membrane monolayer. On the other hand, in the direction across membrane, the highest thermal resistance exists at the center of lipid bilayer where lipid acyl chains face each other. However, asymmetric chain length reduces thermal resistance at the interface between lipid monolayers. Thus, thermal conductivity across the membrane which consists of asymmetric chain length is higher than those which consist of symmetric chain length.
自己組織化単分子膜の水溶媒界面における熱輸送特性(分子スケール(3),一般講演)

菊川豪太, 小原拓, 川口暢, 杵淵郁也, 松本洋一郎

日本流体力学会年会講演論文集　2010　110-110　2010年
出版者・発行元：日本流体力学会

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Molecular dynamics simulations of the interface of self-assembled monolayer (SAM) with two kinds of terminal group and water were performed in order to investigate heat transfer characteristics over the SAM interfaces. Particularly, thermal boundary conductance (TBC) at these interfaces was evaluated and the effect of hydrophobic/hydrophilic property of SAM terminal was discussed. As a result, it was found that the local TBC at the hydroxyl-terminated SAM interface is an order of magnitude larger than that at the methyl-terminated SAM interface. In order to elucidate the reason for this large TBC, components contributing to thermal energy flux across the interface were evaluated in detail, i.e., the total thermal energy flux is decomposed into the contribution of molecular transport and that of energy exchange by molecular interactions.
C141 親和性および非親和性溶媒を用いたSAM界面熱輸送特性の分子動力学解析(マイクロ・ナノスケールの熱輸送現象II)

菊川豪太, 小原拓, 川口暢, 杵淵郁也, 松本洋一郎

熱工学コンファレンス講演論文集　2009　83-84　2009年11月6日
出版者・発行元：一般社団法人日本機械学会

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The present paper focuses on the difference of thermal boundary resistances at the interface of alkanethiolate self-assembled monolayer (SAM) with hydrophobic and hydrophilic solvents. By using nonequilibrium molecular dynamics simulations, a temperature gradient was imposed across the SAM interface and thermal boundary resistance was evaluated at the both interfaces. It was found that the resistance between hydrophobic SAM and hydrophilic solvent is much larger than that at the hydrophobic SAM and hydrophobic solvent. As one of the influential factors in this difference, the matching of vibrational spectrums of molecules at the interface region was examined.
M3-13 分子動力学法を用いた親水性SAMと水の界面熱抵抗の解析(M3 熱流体デバイス)

川口暢, 杵淵郁也, 松本洋一郎, 菊川豪太, 小原拓, 八束真一

マイクロ・ナノ工学シンポジウム　2009　(1)　69-70　2009年10月15日
出版者・発行元：一般社団法人日本機械学会

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The interfacial thermal resistance at the interface of 11-mercapoundecanol (-S(CH_2)_<11>OH) self-assembled monolayer (SAM) adsorbed on Au(111) substrate and water was investigated using nonequilibrium molecular dynamics simulations. As a result, the interfacial thermal resistance was found to be a half of that in the system that consists of 1-dodecanthiol (-S(CH_2)_<11>OH) SAM adsorbed on Au(111) and toluene [Kikugawa, G., et al., J. Chem. Phys. (2009)]. Also the local thermal resistance between SAM and water was found to be very small. We consider that hydrogen bonds between SAM terminal and water contribute the effective thermal energy transfer from SAM to water. The detailed analysis of heat transport phenomena at the interface was performed and the influence of the bonding structure of water molecules near the interface on the thermal resistance was discussed.
数万オーダ粒子系のイメージベース可視化

小田川雅人, 竹島由里子, 藤代一成, 菊川豪太, 小原拓

可視化情報学会誌. Suppl.　28　(1)　73-74　2008年7月1日

ISSN：0916-4731
D245 アルカンチオールSAM膜界面の構造と熱輸送特性のMD解析(分子動力学2)

菊川豪太, 川口暢, 小原拓, 鳥越栄一, 萩原康正, 松本洋一郎

熱工学コンファレンス講演論文集　2007　321-322　2007年11月23日
出版者・発行元：一般社団法人日本機械学会

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In this paper, molecular structure and heat transfer properties at the interface of alkanethiol SAMs (self-assembled monolayers) adsorbed on Au surface and toluene solvent are investigated by using molecular dynamics simulations. Heat transfer properties at the solid-liquid interface have not fully been understood as compared to the solid-solid interface because the phonon-based theoretical framework breaks down. In this study, we focus on the SAM-solvent interfaces on the solid substrate which are widely used not only in the industrial devices, but also in the biomaterials and biodevices. By molecular dynamics simulations of SAM-solvent systems, the molecular structures of toluene and SAM molecules are obtained and the difference of the heat transfer property between the SAM-modified interface and the bare solid-lquid interface (Au-toluene) is discussed.
気液界面における水分子およびL-J流体の微視的構造とダイナミクス

菊川豪太, 高木周, 松本洋一郎, 小原拓

第44回日本伝熱シンポジウム講演論文集　III　585-586　2007年
脂質二重膜の熱エネルギー伝搬特性

中野雄大, 小原拓, 菊川豪太

第44回日本伝熱シンポジウム講演論文集　III　581-582　2007年
Microscopic structure and dynamics of water and L-J liquids at gas-liquid interfaces

Gota Kikugawa, Shu Takagi, Yoichiro Matsumoto, Taku Ohara

Proc. 44th National Heat Transfer Conference　III　585-586　2007年
Thermal energy transfer characteristics of lipid bilayer

Takeo Nakano, Taku Ohara, Gota Kikugawa

Proc. 44th Nationa Heat Transfer Conference　III　581-582　2007年
Structure of liquids and solid-liquid/gas-liquid interfaces and transport characteristics

Taku Ohara, Gota Kikugawa

Fluid Power System　38　(5)　233-238　2007年
液体／固液界面／気液界面の構造と輸送

小原拓, 菊川豪太

フルードパワーシステム　38　(5)　233-238　2007年
出版者・発行元：日本フルードパワーシステム学会
ISSN：1346-7719
A Molecular Dynamics Study on the Interaction between the Electrolytes and Liquid-Vapor Interface

KIKUGAWA Gota, TAKAGI Shu, MATSUMOTO Yoichiro

Thermal science and engineering　12　(4)　87-88　2004年7月1日

ISSN：0918-9963
B143 電解質や極性分子が気液界面に与える影響に関する分子論的考察(B-14 マイクロ・ナノ流体(2),一般講演)

菊川豪太, 高木周, 松本洋一郎

日本流体力学会年会講演論文集　2004　76-77　2004年
出版者・発行元：日本流体力学会

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It has long been well known that the bubble coalescence in various electrolyte or surfactant aqueous solutions is inhibited notably, but the mechanism of inhibition has not been understood currently. It is considered that the dominant factors are different with varying concentrations and that some microscopic structures such as the ionic hydration have the influence on this phenomenon. Therefore, in this study we performed a molecular dynamics simulation of the liquid-vapor equilibrium system in the electrolytes and surfactant aqueous solutions, and especially we focused on the influence of electrolytes or surfactants on electric properties of the interface and dynamic properties of water molecules. From the result, we found that the potential models of electrolytes or waters are important to reproduce the electric structures of the interface.
802 チャネル内マイクロ気泡流の詳細解析(O.S.8-1 気泡混相流)(O.S.8 混相流)

菊川豪太, 蘇秀賢, 高木周, 松本洋一郎

流体工学部門講演会講演論文集　2001　102-102　2001年9月28日
出版者・発行元：一般社団法人日本機械学会
ISSN：1348-2882

︎全件表示 ︎最初の5件までを表示

書籍等出版物 5

マイクロ・ナノ熱工学の進展

界面熱抵抗の制御と設計

エヌ・ティー・エス　2021年5月19日

ISBN: 9784860437220
マイクロ・ナノ熱工学の進展

菊川豪太

エヌ・ティー・エス　2021年5月19日

ISBN: 9784860437220
マイクロ・ナノ熱工学の進展

菊川豪太, 松原裕樹, 小原拓

エヌ・ティー・エス　2021年5月19日

ISBN: 9784860437220
高熱伝導材料の開発 : さらなる熱伝導率の向上のために

技術情報協会

技術情報協会　2019年7月

ISBN: 9784861047541
高度物理刺激と生体応答

小原拓, 中野雄大, 菊川豪太

養賢堂　2017年8月

講演・口頭発表等 228

分子触媒を用いた架橋ネットワーク構造生成過程のためのcat-GRRM/MC/MD法の開発

シーインシャ, 福澤宏宣, 福永翔士, 菊川豪太, 岸本直樹

日本化学会第103春季年会(2023)　2023年3月23日

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K202-2pm-01
多段階可逆反応経路を経由する架橋ネットワーク構造生成過程のためのMultistep-GRRM/MC/MD法の開発

白玉焜, 岸本直樹, 席穎枵, 福永翔士, 福澤宏宣, 菊川豪太

第14回日本複合材料会議　2023年3月15日

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2A-02
有機分子接合した固体接触界面における熱輸送特性の解析

熊谷晴, 菊川豪太

第36回数値流体力学シンポジウム　2022年12月14日

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E05-4
量子化学計算と分子動力学計算を使ったエポキシ樹脂の架橋ネットワーク構造生成過程における反応シミュレーションの開発

岸本直樹, 席穎枵, 福澤宏宣, 菊川豪太

第36回分子シミュレーション討論会　2022年12月5日

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1095P
表面修飾無機固体／高分子界面のナノスケール構造と親和性に関する分子動力学解析

斎藤高雅, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, SURBLYS Donatas

第36回分子シミュレーション討論会　2022年12月5日

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106S
A Study on Nano-Scale Interfacial Phenomena between Surface-Modified Nanoparticle and Dispersed Media 国際会議

Takamasa Saito, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys, Atsuki Komiya

22nd International Symposium on Advanced Fluid Information　2022年11月11日

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CRF-67
Role of pentanol molecules in surface nanobubble composed of nitrogen gas 国際会議

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

22nd International Symposium on Advanced Fluid Information　2022年11月10日

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CRF-28
Analysis of Cross-linking Reaction Process of Network Polymers by Molecular Dynamics Simulation and Quantum Chemical Calculation 国際会議

Yingxiao Xi, Hironobu Fukuzawa, Gota Kikugawa, Naoki Kishimoto

Nineteenth International Conference on Flow Dynamics　2022年11月9日

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OS21-7
表面修飾Al2O3／有機溶媒界面のナノスケール構造と親和性の相関の解明

竹林遼, 斎藤高雅, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, Surblys Donatas

化学工学会新潟大会2022　2022年11月10日

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D220
分子動力学シミュレーションによる表面修飾無機固体／高分子間の界面親和性の評価

斎藤高雅, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, SURBLYS Donatas

第43回日本熱物性シンポジウム　2022年10月26日

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C213
Unveiling the relationship between thermal conductivity and the structure of crosslinked epoxy resin 国際会議

Yinbo Zhao, Gota Kikugawa, Yoshiaki Kawagoe, Keiichi Shirasu, Tomonaga Okabe

The 13th Asian Thermophysical Properties Conference　2022年9月28日

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OS2-3-03
Bottom-up exploration of interaction parameters in reactive DPD simulation for epoxy polymers 国際会議

Kaiwen Li, Gota Kikugawa, Yoshiaki Kawagoe, Yinbo Zhao, Tomonaga Okabe

The 13th Asian Thermophysical Properties Conference　2022年9月28日

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OS2-2-03
Molecular Dynamics Study of Interfacial Affinity between Surface-Modified Inorganic Solid and Polymer 国際会議

Takamasa Saito, Masaki Kubo, Takao Tsukada, Eita Shoji, Gota Kikugawa, Donatas Surblys

The 13th Asian Thermophysical Properties Conference　2022年9月28日

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OS2-1-02
ナノチューブ内に形成された液体メニスカスと衝撃波との干渉に関する分子動力学的研究

鈴木創太, 菊川豪太, 犬飼春太, 田川義之

日本流体力学会年会2022　2022年9月28日
架橋高分子材料の反応DPDシミュレーションにおける相互作用パラメータのボトムアップ探索

李楷文, 菊川豪太, 川越吉晃, Zhao Yinbo, 岡部朋永

第59回日本伝熱シンポジウム　2022年5月18日

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BPA1422
表面修飾無機固体／ポリマー界面における分子構造と親和性の評価

斎藤高雅, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, SURBLYS Donatas

第59回日本伝熱シンポジウム　2022年5月18日

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BPA1411
Multiscale modeling for thermomechanical properties of crosslinked polymers: from quantum chemistry to mesoscale simulation 国際会議招待有り

Gota Kikugawa

The 32nd International Symposium on Transport Phenomena　2022年3月21日
熱硬化性高分子材料の反応DPDシミュレーションにおける相互作用パラメータの探索

Li Kaiwen, 菊川豪太, 川越吉晃, 岡部朋永

第35回数値流体力学シンポジウム　2021年12月15日
機械学習を用いた有機液体の分子スケール構造と熱物性の相関性の解明

河本祐樹, 菊川豪太

第35回数値流体力学シンポジウム　2021年12月15日
Self-organizing map for clarifying relationship between the molecular structure and thermophysical properties 国際会議国際共著

Gota Kikugawa, Yuki Kawamoto, Hari Krishna Chilukoti

The 21st International Symposium on Advanced Fluid Information　2021年10月28日
Molecular dynamics study on effect of surfactant on surface nanobubble 国際会議

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

The 21st International Symposium on Advanced Fluid Information　2021年10月28日
A study on nano-scale interfacial phenomena of surface-modified nanoparticle suspensions 国際会議

Takamasa Saito, Masaki Kubo, Eita Shoji, Takao Tsukada, Gota Kikugawa, Donatas Surblys, Atsuki Komiya

The 21st International Symposium on Advanced Fluid Information　2021年10月28日
構造制御されたポリアクリル酸/ポリエチレンイミン相互積層膜の熱伝導率

佐藤正秀, 伊藤晴美, 的場優仁, 山下雄一郎, 八木貴志, 川越, 吉晃, Surblys Donatas, 松原裕樹, 菊川豪太, 小原拓

第42回日本熱物性シンポジウム　2021年10月26日
有機修飾固体/有機溶媒界面の親和性に及ぼす表面修飾鎖および溶媒の影響

斎藤高雅, 竹林遼, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, Surblys Donatas

第42回日本熱物性シンポジウム　2021年10月25日
Effect of molecular structure and molecular scale interaction on thermal conductivity of fluorocarbon liquids: A molecular dynamics study 国際会議

Shinsuke Kokubo, Hiroki Matsubara, Donatas Surblys, Gota Kikugawa, Taku Ohara

2nd Asian Conference on Thermal Science　2021年10月4日
Obtaining heat flux via atomic stress in systems with many-body interactions and constrained dynamics 国際会議

Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

2nd Asian Conference on Thermal Science　2021年10月4日
Relation between the internal molecular structure and thermomechanical properties of multi-component epoxy resin 国際会議

Yinbo Zhao, Gota Kikugawa, Naoki Kishimoto, Yoshiaki Kawagoe, Keiichi Shirasu, Tomonaga Okabe

2nd Asian Conference on Thermal Science　2021年10月4日
Thermal conduction over PEG-terminated SAM/water interface with different SAM chain lengths 国際会議

Gota Kikugawa, Leton Chandra Saha, Takashi Yagi, Yuichiro Yamashita, Masahide Sato, Taku Ohara

2nd Asian Conference on Thermal Science　2021年10月4日
疎水性の異なるSAM表面上の液滴濡れ状態に関する分子動力学的研究

菊川豪太, 新田則佳, Surblys Donatas, 小原拓

日本流体力学会年会2021　2021年9月22日
SiO2結晶表面近傍における液体水/IPAの物質輸送特性

佐藤大雅, 早坂裕真, Surblys Donatas, 松原裕樹, 中野雄大, 菊川豪太, 小原拓

日本機械学会2021年度年次大会　2021年9月8日
自己組織化単分子膜表面上の液滴接触状態に関する分子動力学的研究

菊川豪太, 新田則佳, SURBLYS Donatas, 小原拓

第58回日本伝熱シンポジウム　2021年5月26日
フルオロカーボン系熱媒の熱伝導機構と熱伝導率の関係に関する分子動力学的研究

小久保信佑, 松原裕樹, Surblys Donatas, 菊川豪太, 小原拓

第58回日本伝熱シンポジウム　2021年5月26日
分子動力学シミュレーションによる有機修飾Al2O3/溶媒間の親和性に及ぼす修飾鎖長および溶媒の影響

竹林遼, 斎藤高雅, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, Surblys Donatas

第58回日本伝熱シンポジウム　2021年5月25日
多体ポテンシャルを有する系の原子応力による熱流束算出

SURBLYS Donatas, 松原裕樹, 菊川豪太, 小原拓

第58回日本伝熱シンポジウム　2021年5月25日
有機修飾固体/有機溶媒界面の付着仕事に及ぼす溶媒および表面修飾鎖の影響

斎藤高雅, 竹林遼, 久保正樹, 塚田隆夫, 庄司衛太, 菊川豪太, Surblys Donatas

化学工学会第86年会　2021年3月22日
量子化学反応経路計算と散逸粒子動力学法を用いた熱硬化性樹脂の架橋形成モデリング

川越吉晃, 菊川豪太, 岡部朋永

第12回日本複合材料会議　2021年3月4日
航空機用難燃性エポキシ樹脂における熱機械特性ならびに熱劣化特性に関する分子動力学シミュレーション

小森翔平, 白須圭一, 川越吉晃, Yinbo ZHAO, 菊川豪太, 岡部朋永

第12回日本複合材料会議　2021年3月3日
量子化学反応経路計算と分子動力学シミュレーションによる多成分系エポキシ樹脂の熱機械特性の解析

Zhao Yinbo, 菊川豪太, 岸本直樹, 川越吉晃, 白須圭一, 岡部朋永

第34回数値流体力学シンポジウム　2020年12月22日
グラフェン上における液体流動発電の出力密度定量国際共著

栗谷京生, 落合耕太朗, Golap Kalita, 種村眞幸, 小宮敦樹, 菊川豪太, 小原拓, 山下一郎, Fumio S. Ohuchi, M. Meyyappan, 寒川誠二, 鷲尾勝由, 岡田健

2020年応用物理学東北支部　2020年12月4日
Molecular Dynamics Simulation on Surface Nanobubble at the Graphite-water Interface with Pentanol Surfactants 国際会議

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

20th International Symposium on Advanced Fluid Information　2020年10月30日
Evaluation of the Work of Adhesion at Organic-modified Al2O3/Organic Solvent Interface by Molecular Dynamics Simulation 国際会議

Takamasa Saito, Eita Shoji, Masaki Kubo, Takao Tsukada, Gota Kikugawa, Donatas Surblys

Seventeenth International Conference on Flow Dynamics　2020年10月28日
PEG基自己組織化単分子層修飾によるAu/水界面の熱抵抗低減

八木貴志, 山下雄一郎, 佐藤正秀, Leton Chandra Saha, 菊川豪太, 小原拓

第41回日本熱物性シンポジウム　2020年10月30日
分子動力学計算による付着仕事に基づいた有機分子修飾Al2O3/有機溶媒界面の親和性評価

斎藤高雅, 庄司衛太, 久保正樹, 塚田隆夫, 菊川豪太, Surblys Donata

化学工学会第51回秋季大会　2020年9月24日
分子動力学法による自己組織化単分子膜表面上の液滴に対する濡れ特性の評価

新田則佳, 菊川豪太

日本流体力学会年会2020　2020年9月18日
有機分子修飾アルミナ表面／有機溶媒間の付着仕事に関する分子動力学解析

斎藤高雅, 庄司衛太, 久保正樹, 塚田隆夫, 菊川豪太, Surblys Donatas

第57回日本伝熱シンポジウム　2020年6月3日
水/IPA液置換挙動の分子動力学解析

中野雄大, Surblys Donatas, 菊川豪太, 小原拓

第57回日本伝熱シンポジウム　2020年6月5日
エポキシ架橋高分子材料の熱機械特性に関する反応分子動力学シミュレーション

菊川豪太, 国枝宏之, ZHAO Yinbo, 大矢豊大, 岡部朋永

第57回日本伝熱シンポジウム　2020年6月4日
交互累積膜内の面内および面垂直方向熱輸送に関する分子動力学解析

川越吉晃, Surblys Donatas, 松原裕樹, 菊川豪太, 岡部朋永, 小原拓

第57回日本伝熱シンポジウム　2020年6月3日
Poly (ethylene glycol)系自己組織化単分子膜/水界面における熱輸送に関する分子動力学シミュレーション

Leton Chandra Saha, 菊川豪太

第57回日本伝熱シンポジウム　2020年6月3日
Evaluation of the thermal conductivity of nanodiamond using transient molecular dynamics simulation 国際会議

Hiroki Matsubara, Gota Kikugawa, Takeshi Bessho, Taku Ohara

The Second Pacific Rim Thermal Engineering Conference　2019年12月16日
自己組織化単分子膜/水界面における熱流束のスペクトル解析

森田修匠, 菊川豪太, Surblys Donatas, 小原拓

第33回数値流体力学シンポジウム　2019年11月27日
固液界面近傍における水の物質輸送特性

早坂裕真, 平澤衛, 中野雄大, 菊川豪太, Surblys Donatas, 小原拓

第33回数値流体力学シンポジウム　2019年11月27日
Molecular dynamics analysis of surfactant effect on water-gas interface 国際会議

Takuma Hori, Gota Kikugawa, Ichiro Ueno, Yoichiro Matsumoto

19th International Symposium on Advanced Fluid Information　2019年11月7日
A study on nano-scale interfacial phenomena of surface-modified nanoparticle suspensiondy on nano-scale interfacial phenomena of surface-modified nanoparticle suspension 国際会議

Eita Shoji, Masaki Kubo, Takao Tsukada, Atsuki Komiya, Gota Kikugawa

19th International Symposium on Advanced Fluid Information　2019年11月7日
ポリマー内熱伝導における多分散性の影響

川越吉晃, Surblys Donatas, 松原裕樹, 菊川豪太, 小原拓

日本流体力学会年会2019　2019年9月14日
ポリエチレングリコールSAM と水界面における界面熱輸送に関する分子動力学的研究

サハレトン, 菊川豪太

日本流体力学会年会2019　2019年9月14日
Applicability of atomic stress to compute heat flux in molecular dynamics 国際会議

Donatas Surblys, Hiroki Matsubara, Gota Kikugawa, Taku Ohara

The 7th Asian Symposium on Computational Heat Transfer and Fluid Flow　2019年9月6日
分子動力学シミュレーションによるナノダイヤモンド熱伝導率の構造依存性の研究

松原裕樹, 菊川豪太, 別所毅, 小原拓

第56回日本伝熱シンポジウム　2019年5月30日
多分散ポリマーの熱伝導特性に関する分子動力学解析国際共著

川越吉晃, Surblys Donatas, 菊川豪太, 小原拓

第56回日本伝熱シンポジウム　2019年5月30日
熱流束スペクトル分解による自己組織化単分子膜の熱伝導特性に関する分子動力学解析

菊川豪太, 森田修匠, 塩見淳一郎, 小原拓

第56回日本伝熱シンポジウム　2019年5月30日
Spectral Decomposition of Heat Conduction over the SAM-Solvent Interface 国際会議

Gota Kikugawa, Junichiro Shiomi, Taku Ohara

2019 MRS Spring Meeting & Exhibit　2019年4月26日
Nanoscale heat transfer over organic substances: from bulk polymers to molecular surface modification 国際会議招待有り

菊川豪太

China-Japan Heat Transfer Symposium 2019　2019年1月15日
固体表面間の極薄液膜における熱輸送に関する分子動力学的解析

劉瀟, Surblys Donatas, 川越吉晃, Saleman Abdul Rafeq, 松原裕樹, 菊川豪太, 小原拓

第32回数値流体力学シンポジウム　2018年12月12日
ポリアクリル酸の熱伝導特性に関する分子動力学解析

川越吉晃, Surblys Donatas, 菊川豪太, 小原拓

第32回数値流体力学シンポジウム　2018年12月12日
熱流スペクトル分解による自己組織化単分子膜と溶媒の界面における熱伝導の理解

菊川豪太, 小原拓

第32回数値流体力学シンポジウム　2018年12月12日
熱伝導率の分子スケール構成要素に対するGreen-Kubo式

松原裕樹, 菊川豪太, 石切山守, 山下征士, 小原拓

第39回日本熱物性シンポジウム　2018年11月13日
Mechanism of Thermal Energy Transfer in Nanoscale Solid-Liquid Systems 国際会議

Masahiko Shibahara, Gota Kikugawa, Taku Ohara

Eighteenth International Symposium on Advanced Fluid Information　2018年11月8日
自己無撞着場理論に基づく高分子材料の動的構造形成の解析

菊川豪太, 大矢豊大, 岡部朋永

日本流体力学会年会2018　2018年9月5日
Kinetic model for molecular transport of liquid mixtures in the vicinity of solid-liquid interfaces 国際会議

Mamoru Hirasawa, Gota Kikugawa, Takeo Nakano, Taku Ohara

16th International Heat Transfer Conference　2018年8月15日
A Molecular dynamics study on thermophysical and transport properties of fluorinated alkane liquids 国際会議

Gota Kikugawa, Naoki Minami, Yingping Fang, Mitsuru Nemoto, Hiroki Matsubara, Taku Ohara

16th International Heat Transfer Conference　2018年8月11日
Molecular Dynamics Study on Thermal Transpiration Flow in Nanochannel with Explicit Wall Model 国際会議

Hiroki Yamaguchi, Gota Kikugawa

31st International Conference on Rarefied Gas Dynamics　2018年7月26日
有機分子修飾膜界面における固液親和性の分子動力学的研究

菊川豪太, 菅原大樹, 小原拓

第55回日本伝熱シンポジウム　2018年5月30日
分子動力学シミュレーションによる会合性液体中熱伝導の分子メカニズムの解析

松原裕樹, 菊川豪太, 石切山守, 山下征士, 小原拓

第55回日本伝熱シンポジウム　2018年5月30日
フルオロカーボンの飽和曲線および熱伝導率に関する分子動力学解析

南直樹, 菊川豪太, Fang YingPing, 根本充, 松原裕樹, 小原拓

第38回日本熱物性シンポジウム　2017年11月7日
Mechanism of thermal energy transfer in nanoscale solid-liquid systems 国際会議

Masahiko Shibahara, Gota Kikugawa, Taku Ohara

17th International Conference on Advanced Fluid Information　2017年11月2日
Thermal boundary conductance and energy transfer modes over the interfaces of various self-assembled monolayers and solvents: A molecular dynamics study 国際会議

Gota Kikugawa, Mitsuru Nemoto, Taku Ohara

9th JSME-KSME Thermal and Fluids Engineering Conference　2017年10月30日
ナノスケール構造内における液体の分子輸送現象

菊川豪太

日本機械学会2017年度年次大会　2017年9月4日
Analysis of molecular energy transfer for the design of thermal medium fluids 国際会議

Taku Ohara, Hiroki Matsubara, Gota Kikugawa

9th US-Japan Joint Seminar on Nanoscale Transport Phenomena　2017年7月4日
Molecular transport of liquids in the confined space: A fundamental study and applications to device process 国際会議

Gota Kikugawa

9th US-Japan Joint Seminar on Nanoscale Transport Phenomena　2017年7月3日
分子動力学シミュレーションによるアルコール液体中の分子スケール熱伝搬の解析:分子内水酸基数の影響

松原裕樹, 菊川豪太, 別所毅, 山下征士, 小原拓

第54回日本伝熱シンポジウム　2017年5月26日
クラスタリング手法を用いた液体の多次元熱流体物性のデータ分析

菊川豪太, 西村優汰, 下山幸治, 小原拓

第54回日本伝熱シンポジウム　2017年5月24日
Thermal rectification effects on solid-liquid interfaces between face-centered cubic (FCC) lattice and a simple liquid 国際会議

Abdul Rafeq, bin Saleman, Hari Krishna Chilukoti, Gota Kikugawa, Taku Ohara

1st Asian Conference on Thermal Sciences　2017年3月30日
Thermal energy transport over the solvent interface of self-assembled monolayers with different fluorination 国際会議

Gota Kikugawa, Mitsuru Nemoto, Taku Ohara

1st Asian Conference on Thermal Sciences　2017年3月29日
Molecular dynamics mechanism of heat conduction in liquid mixtures 国際会議

Yingping Fang, Gota Kikugawa, Hiroki Matsubara, Takeshi Bessho, Seiji Yamashita, Taku Ohara

6th International Symposium on Micro and Nano Technology　2017年3月20日
Molecular dynamics mechanism to determine viscosity of thermal medium liquids 国際会議

4th International Forum on Heat Transfer　2016年11月4日
Molecular mechanism for thermal boundary conductance over fluorinated SAM-solvent interfaces 国際会議

4th International Forum on Heat Transfer　2016年11月4日
Thermal rectification over solid-liquid interfaces of gold (Au) contacting liquid methane (CH4) 国際会議

4th International Forum on Heat Transfer　2016年11月4日
Molecular Transport Phenomena of Liquids Confined in the Nanoscopic Structures 国際会議

Thirteenth International Conference on Flow Dynamics　2016年10月10日
Molecular-Scale Structure of Liquid Alkane Mixtures in the Vicinity of α-Quartz Substrate 国際会議

Thirteenth International Conference on Flow Dynamics　2016年10月10日
Molecular dynamics mechanism of heat conduction in 1-butyl-3-methylimidazolium ionic liquid 国際会議

11th Asian Thermophysical Properties Conference　2016年10月3日
Molecular mechanism of heat conduction in linear alcohol liquids: Effect of chain length 国際会議

11th Asian Thermophysical Properties Conference　2016年10月3日
Molecular thermophysical properties toward the design of liquids and soft matters 国際会議

11th Asian Thermophysical Properties Conference　2016年10月3日
Mechanism of thermal energy transfer in Nanoscale Solid-Liquid Systems 国際会議

The Sixteenth International Symposium on Advanced Fluid Information (AFI-2016)　2016年10月
Molecular Dynamics Study on Thermal Transpiration Flow in Nanochannels 国際会議

The Sixteenth International Symposium on Advanced Fluid Information (AFI-2016)　2016年10月
熱媒液体の粘性を決定する分子動力学機構

日本機械学会熱工学コンファレンス2016　2016年10月
フッ素系SAM－溶媒界面における熱輸送特性に対するフルオロカーボン長さの影響

日本機械学会2016年度年次大会　2016年9月13日
フルオロカーボン系SAMと各種溶媒の界面熱輸送と界面親和性に関する分子論的研究

第53回日本伝熱シンポジウム　2016年5月26日
アルカン・アルコール液体の熱伝導率と分子スケール熱伝搬特性の関係

第53回日本伝熱シンポジウム　2016年5月25日
A molecular dynamics study on molecular diffusion in liquids of water and IPA in the vicinity of solid surfaces and in liquid mixture 国際会議

First Pacific Rim Thermal Engineering Conference　2016年3月14日
2成分混合単純液体の分子スケール熱伝導

日本機械学会東北支部第51期総会講演会　2016年3月11日
フルオロカーボンSAM界面の熱輸送特性に関する分子動力学的研究

日本機械学会東北支部第51期総会講演会　2016年3月11日
1-ブチル-3-メチルイミゾダリウム塩系イオン液体中の熱エネルギー伝搬機構に関する分子動力学シミュレーション

日本機械学会熱工学コンファレンス2015　2015年10月25日
Analysis of molecular transport in the solid-liquid interface region based on the kinetic model 国際会議

12th International Conference on Flow Dynamics　2015年10月
Atomistic heat path analysis of heat transfer in chain polymer liquids 国際会議

12th International Conference on Flow Dynamics　2015年10月
Control of thermal transport across a solid-liquid interface by using self-assembled monolayer 国際会議

The Fifteenth International Symposium on Advanced Fluid Information　2015年10月
Interfacial properties of binary n-alkane mixtures at the liquid-vapor interfaces 国際会議

12th International Conference on Flow Dynamics　2015年10月
Molecular dynamics study on thermal resistance of solid-liquid interfaces 国際会議

The Fifteenth International Symposium on Advanced Fluid Information　2015年10月
Molecular dynamics study on thermal transpiration flow 国際会議

The Fifteenth International Symposium on Advanced Fluid Information　2015年10月
Nonequilibrium molecular dynamics approach to molecular mechanisms of thermal properties in liquid 国際会議

The 3rd International Workshops on Advances in Computational Mechanics　2015年10月
非平衡分子動力学シミュレーションを活用した定圧比熱の計算

第36回日本熱物性シンポジウム　2015年10月1日
自己拡散係数の有限サイズ効果に関する流体力学的解析

日本流体力学会年会2015　2015年9月28日
壁面近傍のナノスケール液体における物質輸送特性

日本機械学会2015年度年次大会　2015年9月14日
自己拡散係数の計算系形状効果に関する流体力学的考察

第52回日本伝熱シンポジウム　2015年6月3日
A molecular dynamics analysis of water/IPA liquid displacement in the vicinity of silica interface 国際会議

Fifth International Symposium on Micro and Nano Technology　2015年5月19日
Influence of computational domain shape in molecular dynamics simulations on self-diffusion coefficient of bulk liquids 国際会議

Fifth International Symposium on Micro and Nano Technology　2015年5月19日
ナノスケール構造中の液体における物質拡散に関する分子動力学的研究

日本機械学会東北支部第50期総会講演会　2015年3月13日
各種アルカンにおける熱伝導に関する非平衡分子動力学シミュレーション

日本機械学会東北支部第50期総会講演会　2015年3月13日
分子動力学計算系におけるバルク液体の自己拡散係数に対する計算系形状の影響

日本機械学会第27回計算力学講演会　2014年11月22日
分子動力学法による鎖状アルカン液体の熱伝導解析：分岐鎖の影響

日本機械学会第27回計算力学講演会　2014年11月22日
バルク液体の自己拡散係数に対する計算系形状の影響

第28回分子シミュレーション討論会　2014年11月14日
分子の構造の違いが分子熱輸送特性に与える影響

第28回分子シミュレーション討論会　2014年11月14日
固液界面近傍におけるアルカン液体の局所的熱伝導率

日本機械学会熱工学コンファレンス2014　2014年11月9日
Structure and transport properties at the liquid-vapor interfaces of binary n-alkane mixtures 国際会議

The 25th International Symposium on Transport Phenomena　2014年11月
Thermal Transport in Lipid Bilayers 国際会議

Eleventh International Conference on Flow Dynamics　2014年10月10日
Thermal Resistance between Nano-Structured Surfaces and Liquids 国際会議

14th International Symposium on Advanced Fluid Information　2014年10月9日
アルカン気液界面の内在的構造と分子拡散に関する分子動力学的研究

日本流体力学会年会2014　2014年9月16日
Lennard-Jonesおよび水バルク液体の自己拡散係数に対する計算系形状の影響

日本機械学会2014年度年次大会　2014年9月8日
Investigation of Thermal Resistance and Heat Conduction at α-Quartz-Liquid Alkane Interfaces Using Nonequilibrium Molecular Dynamics Simulations 国際会議

The 15th International Heat Transfer Conference　2014年8月15日
Molecular Dynamics Viewpoint on Heat Transfer Characteristics of Self-Assembled Monolayers and Polymeric Substances 国際会議

The 8th US-Japan Joint Seminar on Nanoscale Transport Phenomena　2014年7月14日
バルク液体における自己拡散係数の計算系サイズおよび形状効果

第51回日本伝熱シンポジウム　2014年5月22日
Surface Termination Effect on Structure of Decane Liquid in the Vicinity of Alpha-Quartz Surfaces 国際会議

International Conference on Flow Dynamics 2013　2013年11月27日
Crosslinking Effect in Amorphous Polymers on Heat Transfer Characteristics 国際会議

International Conference on Flow Dynamics 2013　2013年11月26日
Thermal Resistance between Nano-Structured Surfaces and Liquids 国際会議

International Conference on Flow Dynamics 2013　2013年11月26日
Study of Alkane Chain Length Influence on Structure and Dynamic Properties at Intrinsic Liquid-Vapour Interfaces 国際会議

12th International Symposium on Fluid Control, Measurement and Visualization (FLUCOME2013)　2013年11月20日
Thermal Transport Characteristics over the Interface of Alkanethiol SAM on a Copper Substrate and Water Solvent 国際会議

12th International Symposium on Fluid Control, Measurement and Visualization (FLUCOME2013)　2013年11月20日
SiO2固体壁近傍における水およびIPAの物質輸送特性に関する分子動力学的研究

日本機械学会熱工学コンファレンス2013　2013年10月19日
A Molecular Dynamics Study on Effect of Temperature on Diffusion in the Vicinity of an Alpha-Quartz Surface/Alkane Interfaces 国際会議

4th International Symposium on Micro and Nanotechnology　2013年10月9日
A molecular dynamics study on mass transport properties in the vicinity of SiO2-water/IPA interfaces 国際会議

4th International Symposium on Micro and Nanotechnology　2013年10月9日
Heat Conduction in Amorphous Polymers with Crosslink Formation 国際会議

4th International Symposium on Micro and Nanotechnology　2013年10月9日
Molecular Dynamics Mechanism of Thermal Energy Transport in Liquid Methane Reproduced by All-Atom and United-Atom Models 国際会議

4th International Symposium on Micro and Nanotechnology　2013年10月9日
架橋を有するアモルファスポリマー材料における熱輸送機構の解明

日本機械学会2013年度年次大会　2013年9月9日
Intrinsic Structure and Diffusion at the Liquid-Vapor Interfaces of Alkanes by Molecular Dynamics Simulation 国際会議

ASME 2013 Summer Heat Transfer Conference　2013年7月17日
Heat Transfer Characteristics over the Interface of Alkanethiolate SAM and Alkane Liquid 国際会議

ASME 2013 Summer Heat Transfer Conference　2013年7月15日
Mass Transport Characteristics of Water/IPA at Silica-Liquid Interfaces 国際会議

ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels　2013年6月
アモルファスポリマー内の架橋による熱伝導特性への影響

第50回日本伝熱シンポジウム　2013年5月
気液瞬時界面近傍における液体アルカンの構造

第50回日本伝熱シンポジウム　2013年5月
銅基盤上のアルカンチオールSAMの構造と熱輸送特性

第50回日本伝熱シンポジウム　2013年5月
Heat Effect of Cross-Linking on Heat Conduction of Amorphous Polymers 国際会議

MRS (Materials Research Society) Spring Meeting 2013　2013年4月4日
Investigation of Interfacial Properties at α-Quartz/Alkane Interfaces Using Molecular Dynamics Simulations 国際会議

2nd International Conference on Advancements in Engineering and Management　2013年2月
SiO2-水/IPA界面近傍における物質輸送に関する分子動力学的研究（吸着層内での分子の挙動とエネルギー状態）

第26回数値流体力学シンポジウム　2012年12月
A Molecular Dynamics Study on Molecular Scale Structure and Mass Transport Properties in the Vicinity of SiO2-Water/IPA Interfaces 国際会議

3rd International Forum on Heat Transfer　2012年11月
Thermal Energy Transfer in Amorphous Polyethylene with Cross-Link Formation 国際会議

2012 Rensselaer Nanotechnology Center Research Symposium　2012年11月
SiO2-水/IPA界面近傍での液膜構造と物質輸送に関する分子動力学的研究

日本機械学会熱工学コンファレンス2012　2012年11月
Molecular Dynamics Simulation of Liquid-Vapor Interfacial Properties of n-Alkanes 国際会議

3rd International Forum on Heat Transfer　2012年11月
SiO2－水/IPA界面近傍における液膜中の構造と物質輸送に対する温度の影響

日本機械学会第4回マイクロ・ナノ工学シンポジウム　2012年10月
Thermal Resistance between Nano-Structured Surfaces and Liquids 国際会議

9th International Conference on Fluid Dynamics, IFS Collaborative Research Forum (AFI/TFI-2012)　2012年9月
直鎖アルカン飽和液中の熱エネルギー伝搬機構に関するAll-Atom分子動力学シミュレーション

日本機械学会2012年度年次大会　2012年9月
Molecular Dynamics Study on Effect of Chain Length on Liquid-Vapor Interfacial Properties of alkanes 国際会議

9th International Conference on Fluid Dynamics　2012年9月
Structure and Transport Characteristics at Liquid-Vapor Interfaces of Alkanes

第49回日本伝熱シンポジウム　2012年5月
SiO2－水/IPA界面近傍における液膜中の構造と物質輸送に関する分子動力学的研究

第49回日本伝熱シンポジウム　2012年5月
All-atomモデルによる各種アルカン飽和液中の熱伝導に関する分子動力学シミュレーション

第49回日本伝熱シンポジウム　2012年5月
Interfacial Heat Transfer Characteristics over the Self-Assembled Monolayer and Solvent Interfaces

7th US-Japan Joint Seminar on Nanoscale Transport Phenomena - Science and Engineering -　2011年12月13日
All-atomモデルによるアルカン飽和液中の熱伝導に関する分子動力学シミュレーション

第25回数値流体力学シンポジウム　2011年12月
Transport Phenomena at Nano-Structured Interfaces 国際会議

The Eleventh International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2011年11月10日
液体メタンの熱伝導を支配する分子動力学機構

第32回日本熱物性シンポジウム　2011年11月
SiO2－水／IPA界面近傍における構造と物質輸送に関する分子動力学的研究

熱工学コンファレンス　2011年10月
親水性および疎水性SAMと水溶媒の界面における熱輸送特性の詳細解析

熱工学コンファレンス2011　2011年10月
マグネタイト-水溶媒界面におけるイオン移動の自由エネルギー分布

第3回マイクロ・ナノ工学シンポジウム　2011年9月27日
Momentum and Heat Transport in Nanoscale Lubrication of Alkane Thin Film Sheared by Self-Assembled Monolayer Surfaces 国際会議

4th International Conference on Heat Transfer and Fluid Flow in Microscale　2011年9月
SiO2－水界面近傍における分子スケール構造と物質輸送に関する分子動力学的研究

第48回日本伝熱シンポジウム　2011年5月
自己組織化膜修飾界面によるアルカン極薄液膜のせん断に関する分子動力学シミュレーション

第48回日本伝熱シンポジウム　2011年5月
A Molecular Dynamics Study on Heat Transfer Characteristics over the Interface of Self-Assembled Monolayer and Water Solvent 国際会議

ASME/JSME 2011 8th Thermal Engineering Joint Conference　2011年3月
Effect of Alkyl Chain Length on Molecular Heat Transfer Characteristics in Lipid Bilayers 国際会議

ASME/JSME 2011 8th Thermal Engineering Joint Conference　2011年3月
Assesment of Different Thermostating Techniques in the Simulation of Molecular Lubrication 国際会議

Tenth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2010年11月2日
Heat Transfer Characteristics at the SAM Interface of Self-Assembled Monolayer with Hydrophobic and Hydrophilic Termini and Solvent 国際会議

7th International Conference on Flow Dynamics　2010年11月
Molecular Momentun Transfer Characteristics of Liquid Behaviors in Shear Flows 国際会議

7th International Conference on Flow Dynamics　2010年11月
Transport Phenomena at Nano-Structured Interfaces 国際会議

IFS Collaborative Research Forum (AFI/TFI-2010)　2010年11月
親水性および疎水性末端基を持つSAM－溶媒界面の熱輸送特性

日本機械学会熱工学コンファレンス2010　2010年10月31日
脂質二重膜の熱輸送特性に対するアルキル鎖界面の影響

第2回マイクロ・ナノ工学シンポジウム　2010年10月15日
自己組織化単分子膜を修飾した固液界面における界面熱コンダクタンスの温度依存性の分子論的研究

第2回マイクロ・ナノ工学シンポジウム　2010年10月15日
せん断流中における脂質二重膜の運動量伝搬特性に関する分子動力学的研究

日本機械学会2010年度年次大会　2010年9月6日
酸化物固体－溶媒界面における溶質移動に関する2次元自由エネルギー局面

日本機械学会2010年度年次大会　2010年9月6日
自己組織化膜修飾が固液界面熱抵抗に与える諸影響の分子論的解析

日本機械学会2010年度年次大会　2010年9月6日
脂質二重膜の熱輸送特性に対する脂質分子種の影響

日本流体力学会年会2010　2010年9月
自己組織化単分子膜の水溶媒界面における熱輸送特性

日本流体力学会年会2010　2010年9月
自己組織化単分子膜のための粒子配置設計支援システム

第38回可視化情報シンポジウム　2010年7月21日
SAM-溶媒界面の熱輸送特性に対する親水性・疎水性の影響

第47回日本伝熱シンポジウム　2010年5月28日
脂質二重膜の熱伝導特性に対する炭化水素鎖長による影響

第47回日本伝熱シンポジウム　2010年5月28日
大規模粒子系の対話的可視化によるパラメータスタディ支援

情報処理学会創立50周年記念（第72回）全国大会　2010年3月9日
Heat Transfer Characteristics at the SAM Interface with Water and Alkane Solvents 国際会議

Joint International Symposia on 3rd Micro & Nano Technology and Micro/Nanoscale Energy Conversion & Transport - 2010　2010年3月
Effects of Intramolecular Energy Transfer on Heat Transport Characteristic in n-Alkane Liquids 国際会議

The ASME 2009 2nd Micro/Nanoscale Heat & Mass Transfer International Conference　2009年12月
Molecular Dynamics Study of International Thermal Resistance of Mercapto-Alkanol Self-Assembled Monolayer and Water 国際会議

ASME 2009 2nd Micro/Nanoscale Heat & Mass Transfer　2009年12月
Heat Transfer Characteristics inside the SAM layer and at the SAM interface 国際会議

6th International Conference on Flow Dynamics　2009年11月
Thermal energy transfer in liquids with ordered/random structures 国際会議

6th International Conference on Flow Dynamics, Sendai, GCOE, IFS-Tsinghua University Joint Workshop　2009年11月
Transport Phenomena at Nano-Structured Interfaces 国際会議

9th International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration, Sendai　2009年11月
親和性および非親和性溶媒を用いたSAM界面熱輸送特性の分子動力学解析

日本機械学会熱工学コンファレンス2009　2009年11月
A molecular dynamics Study on lipid bilayers in shear flows 国際会議

2nd Asian Symposium on Computational Heat Transfer and Fluid Flow, Jeju　2009年10月
Heat transfer characteristics inside the SAM layer and at the SAM interfaces with organic solvents 国際会議

2nd Asian Symposium on Computational Heat Transfer and Fluid Flow, Jeju　2009年10月
SAM修飾による固液界面の界面熱抵抗低減特性

第30回日本熱物性シンポジウム　2009年10月
ポリマー液体の熱伝導率に対する分子内エネルギー伝搬の寄与

第30回日本熱物性シンポジウム　2009年10月
脂質二重膜の熱伝導特性に関する分子動力学解析

第30回日本熱物性シンポジウム講演論文集　2009年10月
分子動力学を用いた親水性SAMと水の界面熱抵抗の解析

第1回マイクロ・ナノ工学シンポジウム　2009年10月
The Effect of Different Thermostating Techniques on Friction and Dissipation in Molecular Dynamics Simulations of Confined Lubrication Films 国際会議

World Tribology Congress 2009　2009年9月10日
SAM内部およびSAM界面における熱輸送特性の分子動力学的研究

日本機械学会2009年度年次大会　2009年9月
コーティング液膜流れの3次元数値解析

日本機械学会2009年度年次大会　2009年9月
せん断流動場における脂質二重膜の運動量輸送特性の異方性に関する分子動力学的研究

日本機械学会2009年度年次大会　2009年9月
ポリマー液体の熱輸送特性に及ぼす分子内エネルギー伝搬の影響

日本機械学会2009年度年次大会　2009年9月
固体表面近傍の水中における物質輸送特性

日本機械学会2009年度年次大会　2009年9月
せん断流中における脂質二重膜の運動量伝搬特性

第46回日本伝熱シンポジウム　2009年5月
マグネタイト－水界面における溶出分子の物質輸送特性

第46回日本伝熱シンポジウム　2009年5月
A molecular dynamics study on heat transfer characteristics in lipid membranes 国際会議

The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年12月
Interfacial heat transfer characteristics at the interface of self-assembled monolayers and organic solvent 国際会議

The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年12月
Point sprite-based visualization of large-scale particle systems 国際会議

The Eighth International Symposium on Advanced Fluid Information and Transdisciplinary Fluid Integration　2008年12月
Molecyular dynamics study on lipid-bilayer membranes in shear flow 国際会議

The Seventh JSME-KSME Thermal and Fluids Engineering Conference　2008年10月
Thermal boundary resistance at the interface of self-assembled monolayers 国際会議

The Seventh JSME-KSME Thermal and Fluids Engineering Conference　2008年10月
A molecular dynamics study on heat conduction characteristics in lipid bilayer 国際会議

The Second International Forum on Heat Transfer　2008年9月
A molecular dynamics study on the heat transfer characteristics at a SAM-solvent interface 国際会議

The Second International Forum on Heat Transfer　2008年9月
SAM-溶媒界面における界面熱抵抗特性の分子論的研究

日本機械学会2008年度年次大会　2008年8月
アルカン液体の固液界面におけるエネルギー・運動量伝搬特性

日本機械学会2008年度年次大会　2008年8月
せん断流中における脂質二重膜の分子動力学的研究

日本機械学会2008年度年次大会　2008年8月
数万オーダ粒子系のイメージベース可視化

第36回可視化情報シンポジウム　2008年7月
SAM膜－溶媒界面における熱輸送特性の分子動力学解析

第45回日本伝熱シンポジウム　2008年5月
脂質二重膜界面における熱輸送特性

第45回日本伝熱シンポジウム　2008年5月
アルカンチオールSAM膜界面の構造と熱輸送特性のMD解析

川口暢, 小原拓, 鳥越栄一, 萩原康正, 松本洋一郎

熱工学コンファレンス2007　2007年11月
Microscopic structure of liquid-vapor interface of water and L-J liquid studied by molecular dynamics simulations 国際会議

Shu Takagi, Yoichiro Matsumoto

The 4th International Conference on Flow Dynamics　2007年9月
A molecular dynamics study on the local structure of liquid-vapor interface of water and L-J fluid 国際会議

Shu Takagi, Yoichiro Matsumoto

2007 ASME-JSME Thermal Engineering Summer Heat Conference　2007年7月
気液界面における水分子およびL-J流体の微視的構造とダイナミクス

高木周, 松本洋一郎, 小原拓

第44回日本伝熱シンポジウム　2007年5月
MDGRAPE-3システムを用いた大規模タンパク質MDシミュレーションの性能評価

米澤康滋, 中村春木, 神谷成敏, 泰地真弘人, 姫野龍太郎

2006年理研シンポジウムスーパーコンピュータの最新動向　2007年3月

︎全件表示 ︎最初の5件までを表示

共同研究・競争的資金等の研究課題 11

質量輸送も含めた超不秩序固体系のメタフォノニクス

塩見淳一郎, ムテルドゥティモテ・マリ・フランソワ, 後藤真宏, 菊川豪太, 李禮林

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (S)

研究機関：The University of Tokyo

2022年4月27日～ 2027年3月31日
ミクロの濡れの保存則：平衡系から非平衡系へ

山口康隆, Surblys Donatas, 大森健史, 菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (B)

研究機関：Osaka University

2022年4月1日～ 2026年3月31日
有機分子修飾界面における分子スケール要因と界面熱輸送・界面親和性との相関性

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Tohoku University

2022年4月1日～ 2025年3月31日
量子アニーリングが拓く高性能マテリアルインフォマティクス基盤の新展開

小林広明, 撫佐昭裕, 阿部圭晃, 岡部朋永, 佐藤雅之, 小松一彦, 大関真之, 菊川豪太, 觀山正道

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (A)

研究機関：Tohoku University

2019年4月1日～ 2023年3月31日

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架橋高分子材料における架橋ネットワーク構造形成のシミュレーションの高速化では，分子動力学シミュレーションと連携する形で粗視化粒子スケールのシミュレーションであるDPD（散逸粒子動力学）法を実装した．また，全原子スケールと同様の反応モデルを組み込み，粗視化レベルでの硬化計算を実現した．さらに，DPDシミュレーションによって得られた構造に対し，全原子スケールの構造テンプレートを貼り付けるリバースマッピング手法を開発した．その結果，全原子シミュレーションに対してコンシステントな構造・物性予測と硬化計算の大幅な速度向上を実現した．高次精度非構造ソルバーを用いた非定常圧縮性流体マクロ解析の大規模実行については，オープンソース（PyFR）のSX-Aurora TSUBASAにおける実装と高速化について研究開発を進めた．その結果，これまで部分的にのみベクトル化が行われていた流束計算のためカーネル（tflux/intcflux）対して，配列の初期化やループ構造の見直しにより完全なベクトル化を達成することが出来た．分子動力学シミュレーション（Peachgk_md）の高速化については，ベクトル化阻害要因であったリストベクトルにおいて，止まり木法を用いることによってベクトル化が可能であることを明らかにし，Peachgk_mdに止まり木法を実装することによってベクトル化率を98.8％まで向上させ，その結果，演算性能が6.5倍に向上した．アニーリングマシンと高性能計算システムの連携によるクラスタリング手法の開発では、クラスタリング条件を定義する制約項をQUBOとは別に定義するアニーリングベースのクラスタリングを量子アニーリングマシンやデジタルアニーリングマシンで行い、QUBO生成などの前処理および、データ集計の後処理などに従来の高性能計算システムを活用する手法を開発した。
ソフトな有機表面材料によって発現する界面親和性に関する分子論的メカニズムの解明

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Tohoku University

2019年4月1日～ 2022年3月31日

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本研究では，分子動力学法を用いて，ソフトな界面を代表する自己組織化単分子膜（SAM）表面の界面親和性を定量評価する手法を確立し，その分子スケール構造や化学的特性に起因する界面親和性発現のメカニズムを定量的に明らかにすることを目標に研究を行った．特に，一般的に利用される親和性の指標である液滴の接触角のみならず，詳細な界面の相互作用エネルギーや，3相接触線付近に設けた検査面における応力テンソル解析など微視的スケールでの解析手段を確立した．
新規機能性を有する有機分子膜の界面親和性に関する分子論的研究

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Tohoku University

2016年4月1日～ 2019年3月31日

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本研究では，ソフトな界面を代表する自己組織化単分子膜（SAM）を介した界面親和性を定量評価する手法を確立し，有機分子薄膜材料の分子スケール構造や化学的特性に起因する界面親和性発現のメカニズムを定量的に明らかにすることを目標に研究を行った．特に，分子動力学法を用いて，固体基盤上での液滴濡れ挙動について，複数のSAMや溶媒種に対して明らかにした．また，現在得られる実験結果との比較を行い，実験データとの差異についても考察を行った．
自己組織化能を有する有機分子薄膜の輸送特性に関する分子論的研究

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Tohoku University

2013年4月1日～ 2016年3月31日

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本研究では，自己組織化単分子膜（SAM）を介した熱輸送機構を明らかにし，分子スケールから新規的な界面修飾材料をデザインする際に有用となる分子レベルの設計指針を模索することを目標に研究を行った．特に，分子動力学法を用いて，SAM修飾の対象として工業・産業応用に際し有望な固体基盤材料やSAM分子の模索を行い，SAM修飾表面と溶媒との組み合わせに対し，界面における熱輸送効率を明らかにした．これらの研究を通じて，界面熱抵抗低減の目的でSAM修飾を適用するかどうかは，用いる溶媒や固体表面の種類によって選択する必要があることを明らかにした．
拡張アンサンブル混合法による蛋白質フォールディング過程の研究

米澤康滋, 菊川豪太, 藤澤雅夫, 吉田久, 橘秀樹, 赤坂一之

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Kinki University

2012年4月1日～ 2015年3月31日

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代表的な拡張アンサンブル法であるMETADとMCMDを効率良く融合したハイブリッド法によって蛋白質の複雑な構造空間を探索するアルゴリズムを,研究代表者が独自に開発した分子シミュレーションプログラムに実装した。さらに高速な分子動力学シミュレーションを実現しサンプリング能力を飛躍的に高める長距離相互作用ポテンシャルの開発に成功して独自開発プログラムに実装した。さらにこれらの手法を様々な生体高分子系に応用してその性能を詳細に検証した。その結果、特にMETADに代表されるタブーサーチ法などの構造空間探索能力は、予め設定された反応座標に強く依存することを明確に示した。
SAM界面の熱物質輸送特性に関わる諸要因の分子論的解析

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Young Scientists (B)

研究機関：Tohoku University

2011年～ 2012年

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本研究では自己組織化単分子膜(SAM)と溶媒との界面における熱輸送特性に与える諸要因を,分子動力学(MD)シミュレーションを用いて明らかにした.固体基盤・アルカンチオールSAM・溶媒系の界面モデルを構築し,界面を介して熱流束を発生させる非平衡分子動力学(NEMD)シミュレーションを行った.金基板-SAM-水溶媒の界面熱輸送特性を解析し,アルカンチオールSAMの末端基によって,局所的な界面熱抵抗に大きな差が現れることを明らかにした.また,基盤への吸着密度の変化が界面熱輸送特性への影響を明らかにした.
高機能化SAM膜界面における熱物質輸送に関する分子論的研究

菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Young Scientists (B)

研究機関：Tohoku University

2008年～ 2009年

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本研究では自己組織化単分子膜(SAM)と溶媒との界面における熱輸送特性を,分子動力学(MD)シミュレーションを用いて明らかにした.固体基板・アルカンチオールSAM・有機溶媒系の界面モデルを構築し,界面を介して熱流束を発生させる非平衡分子動力学(NEMD)シミュレーションを行った.その結果,金基板-トルエン溶媒界面の界面熱抵抗がアルカンチオールSAMの修飾によって大きく低減することがわかった.また,SAM修飾の熱抵抗低減効果について分子論的メカニズムを詳細に解析した.
ナノ熱流体システムの構築を志向した液膜及び固液界面における熱・物質移動の基礎研究

小原拓, 菊川豪太

提供機関：Japan Society for the Promotion of Science

制度名：Grants-in-Aid for Scientific Research

研究種目：Grant-in-Aid for Scientific Research (C)

研究機関：Tohoku University

2006年～ 2008年

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固体のナノ構造(チャネルや修飾表面等)に流体を満たしたものや、生体細胞のように膜で包まれた構造体等、ナノスケールの熱流体を用いてバルク流体にはない特性をもたせた系(ナノ熱流体システム)により熱・運動量・物質の新たな輸送機能を作り出そうとの全体構想の下、基礎研究としてナノ熱流体システムの鍵となる固液界面や液膜・流動性分子膜における熱・物質移動の特性を解析し、その分子スケールメカニズムを明らかにした。

︎全件表示 ︎最初の5件までを表示

Works（作品等） 8

熱遷移流に対する分子動力学解析

2015年～ 2017年
熱遷移流に対する分子動力学解析

2015年～ 2017年
自己組織化単分子膜を利用した固液界面熱輸送の制御

2015年～ 2016年
自己組織化単分子膜を利用した固液界面熱輸送の制御

2015年～ 2016年
高発熱密度素子冷却のための界面修飾分子膜による熱輸送促進の研究

2012年～ 2013年
高発熱密度素子冷却のための界面修飾分子膜による熱輸送促進の研究

2012年～ 2013年
架橋構造を有するポリマー材料内部の熱輸送機構の解明

2012年～
架橋構造を有するポリマー材料内部の熱輸送機構の解明

2012年～

︎全件表示 ︎最初の5件までを表示

その他 4

自己組織化単分子膜を利用した固液界面熱輸送の制御

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分子動力学シミュレーションを用いて，自己組織化単分子膜を利用した固液界面熱輸送の制御を目指す．
熱遷移流に対する分子動力学解析

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分子動力学シミュレーションを用いて熱遷移流の詳細な構造を明らかにする．
架橋構造を有するポリマー材料内部の熱輸送機構の解明

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架橋形成に伴うポリマー素材の熱輸送特性の変化を分子動力学法を利用してミクロスケールから解明する．
高発熱密度素子冷却のための界面修飾分子膜による熱輸送促進の研究

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分子シミュレーションを用いて、固体表面上に修飾された各種有機分子膜と各種熱媒との界面における熱輸送特性を明らかにし、熱輸送促進効果を検討する。