Details of the Researcher

PHOTO

Junpei Okada
Section
International Center for Synchrotron Radiation Innovation Smart
Job title
Specially Appointed Professor(Research)
Degree

  • 博士（工学）（東京大学）

  • 修士（工学）（東京大学）

Research History 6

  • 2025/04 - Present
    東北大学

  • 2015/10 - 2025/03
    Tohoku University　Institute for Materials Research

  • 2012/09 - 2016/03
    Japan Science and Technology Agency

  • 2008/04 - 2015/09
    宇宙航空研究開発機構　宇宙科学研究所　助教

  • 2004/10 - 2008/03
    The University of Tokyo　Graduate School of Frontier Sciences

  • 2003/04 - 2004/09
    理化学研究所　播磨研究所石川X線干渉光学研究室　基礎科学特別研究員

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Education 3

  • The University of Tokyo　The Graduate School of Engineering

    1998/04 - 2003/03

  • Kyoto University　Faculty of Engineering　School of Engineering Science

    1994/04 - 1998/03

  • 私立ヴィアトール学園洛星高等学校

    1990/04 - 1993/03

Committee Memberships 1

  • 日本結晶成長学会　理事（総務委員会）

    2019/04 - 2022/03

Professional Memberships 4

  • マイクログラヴィティ応用学会

  • 日本結晶成長学会

  • 日本物理学会

  • 日本金属学会

Research Interests 3

  • quench

  • high temperature liquids

  • electrostatic levitation

Research Areas 1

  • Nanotechnology/Materials / Inorganic materials /

Awards 1

  1. 第3回関博雄記念賞

    2015/10/01　公益財団法人 関記念財団

Papers 91

  1. Phase relation between supercooled liquid and amorphous silicon Peer-reviewed

    Junpei T. Okada, Patrick H.L. Sit, Ryo Ishikawa, Takehiko Ishikawa, Jinfan Chen, Koji S. Nakayama, Kensaku Maeda, Yoshihiko Yokoyama, Yuki Watanabe, Paul François Paradis, Yasuhiro Watanabe, Susumu Nanao, Yuichi Ikuhara, Kaoru Kimura, Satoshi Uda

    Applied Physics Letters　116　(9)　2020/03/02

    DOI： 10.1063/1.5129059 　

    ISSN： 0003-6951

  2. Visualizing the Mixed Bonding Properties of Liquid Boron with High-Resolution X-Ray Compton Scattering Peer-reviewed

    J. T. Okada, P. H. -L. Sit, Y. Watanabe, B. Barbiellini, T. Ishikawa, Y. J. Wang, M. Itou, Y. Sakurai, A. Bansil, R. Ishikawa, M. Hamaishi, P. -F. Paradis, K. Kimura, T. Ishikawa, S. Nanao

    PHYSICAL REVIEW LETTERS　114　(17)　177401　2015/04

    DOI： 10.1103/PhysRevLett.114.177401 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  3. Persistence of Covalent Bonding in Liquid Silicon Probed by Inelastic X-Ray Scattering Peer-reviewed

    J. T. Okada, P. H. -L. Sit, Y. Watanabe, Y. J. Wang, B. Barbiellini, T. Ishikawa, M. Itou, Y. Sakurai, A. Bansil, R. Ishikawa, M. Hamaishi, T. Masaki, P. -F. Paradis, K. Kimura, T. Ishikawa, S. Nanao

    PHYSICAL REVIEW LETTERS　108　(6)　067402　2012/02

    DOI： 10.1103/PhysRevLett.108.067402 　

    ISSN： 0031-9007

  4. Evidence of the fine pseudogap at the fermi level in Al-based quasicrystals Peer-reviewed

    J. T. Okada, T. Ekino, Y. Yokoyama, T. Takasaki, Y. Watanabe, S. Nanao

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　76　(3)　033707　2007/03

    DOI： 10.1143/JPSJ.76.033707 　

    ISSN： 0031-9015

  5. Atomic and Electronic Structure in MgO–SiO2

    Yuta Shuseki, Shinji Kohara, Tomoaki Kaneko, Keitaro Sodeyama, Yohei Onodera, Chihiro Koyama, Atsunobu Masuno, Shunta Sasaki, Shohei Hatano, Motoki Shiga, Ippei Obayashi, Yasuaki Hiraoka, Junpei T. Okada, Akitoshi Mizuno, Yuki Watanabe, Yui Nakata, Koji Ohara, Motohiko Murakami, Matthew G. Tucker, Marshall T. McDonnell, Hirohisa Oda, Takehiko Ishikawa

    The Journal of Physical Chemistry A　2024/01/18

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.jpca.3c05561 　

    ISSN： 1089-5639

    eISSN： 1520-5215

  6. Heteroepitaxial fabrication of binary colloidal crystals by a balance of interparticle interaction and lattice spacing

    Jun Nozawa, Satoshi Uda, Akiko Toyotama, Junpei Yamanaka, Hiromasa Niinomi, Junpei Okada

    Journal of Colloid and Interface Science　608　873-881　2022/02

    Publisher: Elsevier BV

    DOI： 10.1016/j.jcis.2021.10.041 　

    ISSN： 0021-9797

  7. Heteroepitaxial Growth of Colloidal Crystals: Dependence of the Growth Mode on the Interparticle Interactions and Lattice Spacing

    Jun Nozawa, Satoshi Uda, Hiromasa Niinomi, Junpei Okada, Kozo Fujiwara

    Journal of Physical Chemistry Letters　6995-7000　2022

    DOI： 10.1021/acs.jpclett.2c01707 　

    eISSN： 1948-7185

  8. Chiral Optical Force Generated by a Superchiral Near-Field of a Plasmonic Triangle Trimer as Origin of Giant Bias in Chiral Nucleation: A Simulation Study

    Hiromasa Niinomi, Teruki Sugiyama, An-Chieh Cheng, Miho Tagawa, Toru Ujihara, Hiroshi Y. Yoshikawa, Ryuzo Kawamura, Jun Nozawa, Junpei T. Okada, Satoshi Uda

    JOURNAL OF PHYSICAL CHEMISTRY C　125　(11)　6209-6221　2021/03

    DOI： 10.1021/acs.jpcc.0c11109 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  9. Very sharp diffraction peak in nonglass-forming liquid with the formation of distorted tetraclusters

    Chihiro Koyama, Shuta Tahara, Shinji Kohara, Yohei Onodera, Didrik R. Småbråten, Sverre M. Selbach, Jaakko Akola, Takehiko Ishikawa, Atsunobu Masuno, Akitoshi Mizuno, Junpei T. Okada, Yuki Watanabe, Yui Nakata, Koji Ohara, Haruka Tamaru, Hirohisa Oda, Ippei Obayashi, Yasuyuki Hiraoka, Osami Sakata

    NPG Asia Materials　12　(1)　2020/12

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41427-020-0220-0 　

    ISSN： 1884-4049

    eISSN： 1884-4057

    More details Close

    <title>Abstract</title>Understanding the liquid structure provides information that is crucial to uncovering the nature of the glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays to liquid (<italic>l</italic>)-Er2O3 to discover its structure. The sample densities are measured by electrostatic levitation at the International Space Station. Liquid Er2O3 displays a very sharp diffraction peak (principal peak). Applying a combined reverse Monte Carlo – molecular dynamics approach, the simulations produce an Er–O coordination number of 6.1, which is comparable to that of another nonglass-forming liquid, <italic>l</italic>-ZrO2. The atomic structure of <italic>l</italic>-Er2O3 comprises distorted OEr4 tetraclusters in nearly linear arrangements, as manifested by a prominent peak observed at ~180° in the Er–O–Er bond angle distribution. This structural feature gives rise to long periodicity corresponding to the sharp principal peak in the X-ray diffraction data. A persistent homology analysis suggests that <italic>l</italic>-Er2O3 is homologically similar to the crystalline phase. Moreover, electronic structure calculations show that <italic>l</italic>-Er2O3 has a modest band gap of 0.6 eV that is significantly reduced from the crystalline phase due to the tetracluster distortions. The estimated viscosity is very low above the melting point for <italic>l</italic>-ZrO2, and the material can be described as an extremely fragile liquid.

  10. Densities of liquid Re, Os, and Ir, and their temperature dependence measured by an electrostatic levitator

    Takehiko Ishikawa, Chihiro Koyama, Paul-François Paradis, Junpei T. Okada, Yui Nakata, Yuki Watanabe

    International Journal of Refractory Metals and Hard Materials　92　105305-105305　2020/11

    Publisher: Elsevier BV

    DOI： 10.1016/j.ijrmhm.2020.105305 　

    ISSN： 0263-4368

  11. Search for the boron quasicrystal by first-principle-calculation

    Takahiro Takahashi, Koichi Kitahara, Yukari Katsura, Junpei Okada, Yu-ichiro Matsushita, Kaoru Kimura

    Solid State Sciences　108　106377-106377　2020/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.solidstatesciences.2020.106377 　

    ISSN： 1293-2558

  12. High-Density Liquid Water at a Water–Ice Interface

    Hiromasa Niinomi, Tomoya Yamazaki, Hiroki Nada, Tetsuya Hama, Akira Kouchi, Junpei T. Okada, Jun Nozawa, Satoshi Uda, Yuki Kimura

    The Journal of Physical Chemistry Letters　11　(16)　6779-6784　2020/08/20

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.jpclett.0c01907 　

    ISSN： 1948-7185

    eISSN： 1948-7185

  13. Plasmonic Manipulation of Sodium Chlorate Chiral Crystallization: Directed Chirality Transfer via Contact-Induced Polymorphic Transformation and Formation of Liquid Precursor

    Hiromasa Niinomi, Teruki Sugiyama, Miho Tagawa, Toru Ujihara, Takashige Omatsu, Katsuhiko Miyamoto, Hiroshi Y. Yoshikawa, Ryuzo Kawamura, Jun Nozawa, Junpei T. Okada, Satoshi Uda

    Crystal Growth & Design　20　(8)　5493-5507　2020/08/05

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.cgd.0c00693 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  14. Accurate Synchrotron Hard X-ray Diffraction Measurements on High-Temperature Liquid Oxides Peer-reviewed

    K. Ohara, Y. Onodera, S. Kohara, C. Koyama, A. Masuno, A. Mizuno, J. T. Okada, S. Tahara, Y. Watanabe, H. Oda, Y. Nakata, H. Tamaru, T. Ishikawa, O. Sakata

    Int. J. Microgravity Sci. Appl.　37　(2)　370202–1-370202–7　2020/04

    DOI： 10.15011/jasma.37.2.370202 　

    ISSN： 0915-3616

    eISSN： 2188-9783

  15. Effects of solution flow on the growth of colloidal crystals Peer-reviewed

    Jun Nozawa*, Satoshi Uda, Guo Suxia, Akiko Toyotama, Junpei Yamanaka, Hiromasa Niinomi, Junpei Okada

    Langmuir　in press　(16)　4324-4331　2020/04

    DOI： 10.1021/acs.langmuir.0c00335 　

    ISSN： 0743-7463

  16. Growth and One-Dimensional Heteroepitaxy of Binary Colloidal Crystals Peer-reviewed

    Jun Nozawa*, Satoshi Uda, Akiko Toyotama,, Junpei Yamanaka,, Hiromasa Niinomi,, Junpei Okada

    Crystal Growth and Design　in press　2020/03

  17. Secondary phase formation by liquid immiscibility in Ca3Ta(Ga1−xAlx)3Si2O14 melt Peer-reviewed

    Yuki Honda, Hiromasa Niinomi, Jun Nozawa, Junpei Okada, Satoshi Uda

    Journal of Crystal Growth　522　117-124　2019/09

    DOI： 10.1016/j.jcrysgro.2019.06.022 　

  18. In Situ Microscopic Observation on Surface Kinetics in Optical Trapping-Induced Crystal Growth: Step Formation, Wetting Transition, and Nonclassical Growth Peer-reviewed

    Hiromasa Niinomi, Teruki Sugiyama, Toru Ujihara, Suxia Guo, Jun Nozawa, Junpei Okada, Takashige Omatsu, Satoshi Uda

    Crystal Growth & Design　19　(7)　4138-4150　2019/07

    DOI： 10.1021/acs.cgd.9b00600 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  19. Effect of Substrate on Nucleation Rate of Two-Dimensional Colloidal Crystals Peer-reviewed

    Suxia Guo, Jun Nozawa, Masashi Mizukami, Kazue Kurihara, Akiko Toyotama, Junpei Yamanaka, Hiromasa Niinomi, Junpei Okada, Satoshi Uda

    Crystal Growth and Design　19　(6)　3215-3221　2019/06/05

    DOI： 10.1021/acs.cgd.9b00069 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  20. Kink Distance and Binding Energy of Colloidal Crystals Peer-reviewed

    Jun Nozawa, Satoshi Uda, Suxia Guo, Akiko Toyotama, Junpei Yamanaka, Naoki Ihara, Junpei Okada

    Crystal Growth & Design　18　(10)　6078-6083　2018/10/03

    DOI： 10.1021/acs.cgd.8b00942 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  21. Step Kinetics Dependent on the Kink Generation Mechanism in Colloidal Crystal Growth Peer-reviewed

    Jun Nozawa, Satoshi Uda, Suxia Guo, Akiko Toyotama, Junpei Yamanaka, Junpei Okada, Haruhiko Koizumi

    Crystal Growth & Design　18　(5)　2948-2955　2018/05/02

    DOI： 10.1021/acs.cgd.8b00063 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  22. Thermophysical Properties of Zr-O Liquid Alloys Measured by Electrostatic Levitation Peer-reviewed

    Ohishi Yuji, Kondo Toshiki, Ishikawa Takehiko, Okada Junpei T, Watanabe Yuki, Muta Hiroaki, Kurosaki Ken, Yamanaka Shinsuke

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　35　(1)　2018

    DOI： 10.15011//jasma.35.350105 　

    ISSN： 0915-3616

  23. Crystallization Technique of High-Quality Protein Crystals Controlling Surface Free Energy Peer-reviewed

    Haruhiko Koizumi, Satoshi Uda, Katsuo Tsukamoto, Masaru Tachibana, Kenichi Kojima, Junpei Okada, Jun Nozawa

    CRYSTAL GROWTH & DESIGN　17　(12)　6712-6718　2017/12

    DOI： 10.1021/acs.cgd.7b01315 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  24. Heterogeneous Nucleation of Colloidal Crystals on a Glass Substrate with Depletion Attraction Peer-reviewed

    Suxia Guo, Jun Nozawa, Sumeng Hu, Haruhiko Koizumi, Junpei Okada, Satoshi Uda

    LANGMUIR　33　(40)　10543-10549　2017/10

    DOI： 10.1021/acs.langmuir.7b01906 　

    ISSN： 0743-7463

  25. Measurement of spectral emissivity and constant pressure heat capacity of liquid platinum with an electrostatic levitator Peer-reviewed

    Takehiko Ishikawa, Junpei T. Okada, Paul-Francois Paradis, Yuki Watanabe

    JOURNAL OF CHEMICAL THERMODYNAMICS　112　7-12　2017/09

    DOI： 10.1016/j.jct.2017.04.006 　

    ISSN： 0021-9614

    eISSN： 1096-3626

  26. Effect of an External Electric Field on the Kinetics of Dislocation-Free Growth of Tetragonal Hen Egg White Lysozyme Crystals Peer-reviewed

    Haruhiko Koizumi, Satoshi Uda, Kozo Fujiwara, Junpei Okada, Jun Nozawa

    CRYSTALS　7　(6)　2017/06

    DOI： 10.3390/cryst7060170 　

    ISSN： 2073-4352

  27. 無容器浮遊法を用いたガラスおよび高温融液の構造と物性

    水野章敏, 増野敦信, 岡田純平, 石川毅彦

    セラミックス　52　(5)　349-351　2017/05

  28. Two-Dimensional Nucleation on the Terrace of Colloidal Crystals with Added Polymers Peer-reviewed

    Jun Nozawa, Satoshi Uda, Suxia Guo, Sumeng Hu, Akiko Toyotama, Junpei Yamanaka, Junpei Okada, Haruhiko Koizumi

    LANGMUIR　33　(13)　3262-3269　2017/04

    DOI： 10.1021/acs.langmuir.6b04532 　

    ISSN： 0743-7463

  29. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation Peer-reviewed

    Yuji Ohishi, Toshiki Kondo, Takehiko Ishikawa, Junpei T. Okada, Yuki Watanabe, Hiroaki Muta, Ken Kurosaki, Shinsuke Yamanaka

    JOURNAL OF NUCLEAR MATERIALS　485　129-136　2017/03

    DOI： 10.1016/j.jnucmat.2016.12.002 　

    ISSN： 0022-3115

    eISSN： 1873-4820

  30. Two-dimensional nucleation in the colloidal crystal

    Nozawa Jun, Guo Suxia, Hu Sumeng, Toyotama Akiko, Yamanaka Junpei, Koizumi Haruhiko, Okada Junpei, Uda Satoshi

    Journal of the Japanese Association for Crystal Growth　44　(2)　96-102　2017

    Publisher: The Japanese Association for Crystal Growth

    DOI： 10.19009/jjacg.44.2_96 　

    ISSN： 2188-7268

    More details Close

    <p>  The two-dimensional (2D) nucleation is the predominant growth mechanisms for colloidal crystals whose particle interaction is attractive. The colloidal crystallization in the attractive system has recently been regarded as a promising method to fabricate varieties of complex nano-structures possessing innovative functionality. In the present study, polymers are added to a colloidal suspension to generate a depletion attractive force, and the detailed 2D nucleation process on the terrace of the colloidal crystals is investigated. We first measured the nucleation rate at various area fractions of particles on the terrace, φarea. In situ observations at single-particle resolution enable us to measure the steady-state homogeneous 2D nucleation rate, J, and the critical size of nuclei, r*, and the relationship between them and φarea is found to agree well with classical nucleation theory (CNT). The step free energy, γ, derived from the nucleation theory is found to vary according to the strength of attraction, which is tuned by the concentration of the polymer as a depletant.</p>

  31. Emissivity Measurements of Molten Metals with an Electrostatic Levitator Peer-reviewed

    Ishikawa Takehiko, Okada Junpei T, Paradis Paul-Francois, Watanabe Yuki

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　34　(3)　2017

    DOI： 10.15011//jasma.34.340305 　

    ISSN： 0915-3616

  32. Spectral emissivity and constant pressure heat capacity of molten nickel and rhodium measured by spectrometers combined with an electrostatic levitator Peer-reviewed

    Takehiko Ishikawa, Junpei T. Okada, Paul-Francois Paradis, Yuki Watanabe

    JOURNAL OF CHEMICAL THERMODYNAMICS　103　107-114　2016/12

    DOI： 10.1016/j.jct.2016.08.012 　

    ISSN： 0021-9614

    eISSN： 1096-3626

  33. Synchrotron X-ray Scattering Measurements of Disordered Materials Peer-reviewed

    Shinji Kohara, Koji Ohara, Hiroo Tajiri, Chulho Song, Osami Sakata, Takeshi Usuki, Yasuhiko Benino, Akitoshi Mizuno, Atsunobu Masuno, Junpei T. Okada, Takehiko Ishikawa, Shinya Hosokawa

    ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS　230　(3)　339-368　2016/03

    DOI： 10.1515/zpch-2015-0654 　

    ISSN： 0942-9352

  34. Thermophysical properties of molten core materials: Zr-Fe alloys measured by electrostatic levitation Peer-reviewed

    Yuji Ohishi, Hiroaki Muta, Ken Kurosaki, Junpei T. Okada, Takehiko Ishikawa, Yuki Watanabe, Shinsuke Yamanaka

    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY　53　(12)　1943-1950　2016

    DOI： 10.1080/00223131.2016.1174626 　

    ISSN： 0022-3131

    eISSN： 1881-1248

  35. Non-Contact Measurement of Thermophysical Properties of Fe, Fe-C, and Fe-C-Mn Alloys in Solid, Supercooled, and Stable Liquid Phases Peer-reviewed

    Sangho Jeon, Dong-Hee Kang, Shin Hwan Kang, Shin Eon Kang, Junpei T. Okada, Takehiko Ishikawa, Sooheyong Lee, Geun Woo Lee

    ISIJ INTERNATIONAL　56　(4)　719-722　2016

    DOI： 10.2355/isijinternational.ISIJINT-2015-526 　

    ISSN： 0915-1559

    eISSN： 1347-5460

  36. FT-IR emissivity measurements of Nb melt using an electrostatic levitation furnace Peer-reviewed

    K. Sakata, Y. Watanabe, J. T. Okada, M. V. Kumar, P. -F. Paradis, T. Ishikawa

    JOURNAL OF CHEMICAL THERMODYNAMICS　91　116-120　2015/12

    DOI： 10.1016/j.jct.2015.07.030 　

    ISSN： 0021-9614

    eISSN： 1096-3626

  37. Overview of the Electrostatic Levitation Furnace (ELF) for the International Space Station (ISS) Peer-reviewed

    Tamaru Haruka, Ishikawa Takehiko, Okada Junpei T, Nakamura Yasuhiro, Ohkuma Hayato, Yukizono Satoshi, Sakai Yumiko, Takada Tetsuya

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　32　(1)　2015

    ISSN： 0915-3616

  38. Surface Tension and Viscosity Measurement of highly Viscous Melts using a Sample Rotation Peer-reviewed

    Ishikawa Takehiko, Okada Junpei, Paradis Paul-Francois, Watanabe Yuki, Watanabe Masahito

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　32　(1)　2015

    ISSN： 0915-3616

  39. Thermophysical Property Measurements of Oxide Melts at High Temperature by Electrostatic Levitation Furnace on the ISS Peer-reviewed

    Ishikawa Takehiko, Okada Junpei T, Watanebe Yuki, Tamaru Haruka, Nakamura Yasuhiro

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　32　(4)　2015

    DOI： 10.15011/ijmsa.32.320410 　

    ISSN： 0915-3616

  40. Results of Microgravity Experiments Using the Balloon Operated Vehicle with a New Drag-Free Control Method Peer-reviewed

    Kikuchi Masao, Ishikawa Takehiko, Yamamoto Shin, Sawai Shujiro, Maru Yusuke, Sakai Shinichiro, Bando Nobutaka, Shimizu Shigehito, Kobayashi Hiroaki, Yoshimitsu Tetsuo, Kan Yuji, Mizushima Takanari, Fukuyama Seijiro, Okada Junpei, Yoda Shinichi, Fuke Hideyuki, Kakehashi Yuya, Hashimoto Tatsuaki

    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION　32　(2)　2015

    DOI： 10.15011/ijmsa.32.320211 　

    ISSN： 0915-3616

    eISSN： 2188-9783

  41. Atomic and electronic structures of an extremely fragile liquid Peer-reviewed

    Shinji Kohara, Jaakko Akola, Leonid Patrikeev, Matti Ropo, Koji Ohara, Masayoshi Itou, Akihiko Fujiwara, Jumpei Yahiro, Junpei T. Okada, Takehiko Ishikawa, Akitoshi Mizuno, Atsunobu Masuno, Yasuhiro Watanabe, Takeshi Usuki

    NATURE COMMUNICATIONS　5　5892　2014/12

    DOI： 10.1038/ncomms6892 　

    ISSN： 2041-1723

  42. Surface tension measurement using sample rotation combined with electrostatic levitation Peer-reviewed

    Takehiko Ishikawa, Junpei T. Okada, Paul-Francois Paradis, Yuki Watanabe, Malahalli Vijaya Kumar, Masahito Watanabe

    JAPANESE JOURNAL OF APPLIED PHYSICS　53　(12)　126601　2014/12

    DOI： 10.7567/JJAP.53.126601 　

    ISSN： 0021-4922

    eISSN： 1347-4065

  43. Thermoelectric Properties of Al-Ga-Pd-Re Icosahedral Quasicrystals Peer-reviewed

    Y. Takagiwa, T. Kamimura, J. T. Okada, K. Kimura

    MATERIALS TRANSACTIONS　55　(8)　1226-1231　2014/08

    DOI： 10.2320/matertrans.E-M2014825 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  44. Density measurement of glass and liquid CaAl2O4 using a pressurized electrostatic levitator Peer-reviewed

    Malahalli Vijaya Kumar, Junpei T. Okada, Takehiko Ishikawa, Paul-Francois Paradis, Yuki Watanabe

    MEASUREMENT SCIENCE AND TECHNOLOGY　25　(8)　085301　2014/08

    DOI： 10.1088/0957-0233/25/8/085301 　

    ISSN： 0957-0233

    eISSN： 1361-6501

  45. Thermophysical Properties of Platinum Group Metals in their Liquid Undercooled and Superheated Phases Measurements in the liquid state, including the undercooled region, over wide temperature ranges with an electrostatic levitator Peer-reviewed

    Paul-Francois Paradis, Takehiko Ishikawa, Junpei T. Okada

    JOHNSON MATTHEY TECHNOLOGY REVIEW　58　(3)　124-136　2014/07

    DOI： 10.1595/147106714X682355 　

    eISSN： 2056-5135

  46. Nanosized Nucleus-Supercooled Liquid Interfacial Free Energy and Thermophysical Properties of Early and Late Transition Liquid Metals Peer-reviewed

    Dong-Hee Kang, Sangho Jeon, Hanbyeol Yoo, Takehiko Ishikawa, Junpei T. Okada, Paul-Francois Paradis, Geun Woo Lee

    CRYSTAL GROWTH & DESIGN　14　(3)　1103-1109　2014/03

    DOI： 10.1021/cg401597p 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  47. Materials properties measurements and particle beam interactions studies using electrostatic levitation Peer-reviewed

    Paul-Francois Paradis, Takehiko Ishikawa, Geun-Woo Lee, Dirk Holland-Moritz, Juergen Brillo, Won-Kyu Rhim, Junpei T. Okada

    MATERIALS SCIENCE & ENGINEERING R-REPORTS　76　1-53　2014/02

    DOI： 10.1016/j.mser.2013.12.001 　

    ISSN： 0927-796X

    eISSN： 1879-212X

  48. Thermal and optical properties of glass and crystalline phases formed in the binary R2O3-Al2O3 (R = La-Lu and Y) system Peer-reviewed

    Malahalli Vijaya Kumar, Takehiko Ishikawa, B. Basavalingu, Junpei T. Okada, Yuki Watanabe

    JOURNAL OF APPLIED PHYSICS　113　(19)　193503　2013/05

    DOI： 10.1063/1.4805536 　

    ISSN： 0021-8979

  49. Microstructure and Magnetic Properties of Metastable RFeO3 (R: Rare-earth element) Formed from Undercooled Melt Peer-reviewed

    Malahalli Vijaya Kumar, Kazuhiko Kuribayashi, Jianding Yu, Junpei T. Okada, Takehiko Ishikawa

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY　96　(3)　995-1002　2013/03

    DOI： 10.1111/jace.12127 　

    ISSN： 0002-7820

    eISSN： 1551-2916

  50. Electrostatic levitation furnace experiment for "Kibo" on the international space station

    Tetsuhito Fuse, Yasuhiro Nakamura, Keiji Murakami, Koichi Shibasaki, Haruka Tamaru, Hayato Ohkuma, Satoshi Yukizono, Takehiko Ishikawa, Junpei Okada, Tetsuya Takada, Vumiko Sakai, Tatsuya Arai, Naoki Fujino

    Proceedings of the International Astronautical Congress, IAC　1　758-762　2013

    Publisher: International Astronautical Federation, IAF

    ISSN： 0074-1795

  51. Electrostatic levitation furnace for the international space station

    Keiji Murakami, Naokiyo Koshikawa, Koichi Shibasaki, Takehiko Ishikawa, Junpei Okada, Tai Nakamura, Yukiko Yamaura, Tatsuya Arai, Naoki Fujino, Tetsuya Takada

    Advances in the Astronautical Sciences　146　705-708　2013

    ISSN： 0065-3438

  52. Two-dimensional time-resolved X-ray diffraction study of liquid/solid fraction and solid particle size in Fe-C binary system with an electrostatic levitator furnace Peer-reviewed

    M. Yonemura, J. Okada, Y. Watanabe, T. Ishikawa, S. Nanao, T. Shobu, H. Toyokawa

    Journal of Physics: Conference Series　425　(9)　2013

    DOI： 10.1088/1742-6596/425/9/092004 　

    ISSN： 1742-6596 1742-6588

  53. ELECTROSTATIC LEVITATION FURNACE FOR THE INTERNATIONAL SPACE STATION Peer-reviewed

    Murakami Keiji, Koshikawa Naokiyo, Shibasaki Koichi, Ishikawa Takehiko, Okada Junpei, Nakamura Tai, Yamaura Yukiko, Arai Tatsuya, Fujino Naoki, Takada Tetsuya

    SPACE FOR OUR FUTURE　146　705-708　2013

    ISSN： 1081-6003

  54. Viscosity of molten Mo, Ta, Os, Re, and W measured by electrostatic levitation Peer-reviewed

    Takehiko Ishikawa, Paul-François Paradis, Junpei T. Okada, Malahalli Vijaya Kumar, Yuki Watanabe

    Journal of Chemical Thermodynamics　65　1-6　2013

    DOI： 10.1016/j.jct.2013.05.036 　

    ISSN： 0021-9614 1096-3626

  55. Spectral emissivity measurements of liquid refractory metals by spectrometers combined with an electrostatic levitator Peer-reviewed

    Takehiko Ishikawa, Yusuke Ito, Junpei T. Okada, Paul-Francois Paradis, Yuki Watanabe, Tadahiko Masaki

    MEASUREMENT SCIENCE AND TECHNOLOGY　23　(12)　125602　2012/12

    DOI： 10.1088/0957-0233/23/12/125602 　

    ISSN： 0957-0233

    eISSN： 1361-6501

  56. Real-time x-ray diffraction of metastable phases during solidification from the undercooled LuFeO3 melt by two-dimensional detector at 1 kHz Peer-reviewed

    Kumar Malahalli Vijaya, Kuribayashi K, Nagashio K, Ishikawa T, Okada J, Yu J, Yoda S, Katayama Y

    APPLIED PHYSICS LETTERS　100　(19)　2012/05/07

    DOI： 10.1063/1.4712124 　

    ISSN： 0003-6951

  57. Two-Dimensional Time-Resolved X-ray Diffraction Study of Liquid/solid Fraction in Fe-C Binary System with an Electrostatic Levitator Furnace Peer-reviewed

    Yonemura Mitsuharu, Okada Junpei, Watanabe Yasuhiro, Ishikawa Takehiko, Nanao Susumu, Shobu Takahisa, Shiro Ayumi, Fujishiro Tomoyuki, Toyokawa Hidenori

    CHINESE JOURNAL OF PHYSICS　50　(2)　243-255　2012/04

    ISSN： 0577-9073

  58. Viscosity measurements of molten refractory metals using an electrostatic levitator Peer-reviewed

    Takehiko Ishikawa, Paul-Francois Paradis, Junpei T. Okada, Yuki Watanabe

    MEASUREMENT SCIENCE AND TECHNOLOGY　23　(2)　025305　2012/02

    DOI： 10.1088/0957-0233/23/2/025305 　

    ISSN： 0957-0233

    eISSN： 1361-6501

  59. Supercooling of Homogeneous Liquid Phase of Liquid Metals and Alloys -Poor Supercooling around the Eutectic Composition of Liquid Ni-Nb System- Peer-reviewed

    Toshio Itami, Junpei Okada, Yuki Watanabe, Takehiko Ishikawa, Shinichi Yoda

    JOURNAL OF THE JAPAN INSTITUTE OF METALS　75　(12)　690-696　2011/12

    DOI： 10.2320/jinstmet.75.690 　

    ISSN： 0021-4876

    eISSN： 1880-6880

  60. Thermophysical Property Measurements of High Temperature Melts Using an Electrostatic Levitation Method Peer-reviewed

    Takehiko Ishikawa, Junpei T. Okada, Paul-Francois Paradis, Yuki Watanabe

    JAPANESE JOURNAL OF APPLIED PHYSICS　50　(11)　11RD03　2011/11

    DOI： 10.1143/JJAP.50.11RD03 　

    ISSN： 0021-4922

  61. Thermoelectric Properties of the Narrow-Gap Intermetallic Compound Ga2Ru: Effect of Re Substitution for Ru Atoms Peer-reviewed

    Yoshiki Takagiwa, Junpei Tamura Okada, Kaoru Kimura

    JOURNAL OF ELECTRONIC MATERIALS　40　(5)　1067-1072　2011/05

    DOI： 10.1007/s11664-011-1543-y 　

    ISSN： 0361-5235

  62. Atomic Dynamics in Extreme Environments via Inelastic X-Ray Scattering at SPring-8 Peer-reviewed

    Alfred Q.R. Baron, Masanori Inui, Ejii Ohtani, Hiroshi Fukui, Shinya Hosokawa, Tadahiko Masaki, Daisuke Ishikawa, Takeshi Sakai, Junpei T. Okada, Satoshi Tsutsui, Hiroshi Uchiyama

    Synchrotron Radiation News　23　(6)　17-25　2010/12

    DOI： 10.1080/08940886.2010.531678 　

    ISSN： 0894-0886

    eISSN： 1931-7344

  63. Composition dependence of thermoelectric properties of binary narrow-gap Ga67-xRu33+x compound Peer-reviewed

    Y. Takagiwa, J. T. Okada, K. Kimura

    JOURNAL OF ALLOYS AND COMPOUNDS　507　(2)　364-369　2010/10

    DOI： 10.1016/j.jallcom.2010.07.204 　

    ISSN： 0925-8388

  64. Supercooling of Homogeneous Liquid Phase of Liquid Metals and Alloys -Poor Supercooling around the Eutectic Composition of Liquid Ni-Nb System- Peer-reviewed

    Itami Toshio, Okada Junpei, Watanabe Yuki, Ishikawa Takehiko, Yoda Shinichi

    MATERIALS TRANSACTIONS　51　(9)　1510-1515　2010/09

    DOI： 10.2320/matertrans.MAW201025 　

    ISSN： 1345-9678

  65. Thermoelectric Properties of Icosahedral Al-Pd-(Mn or Re) Quasicrystals: Improvement of the ZT Value by Ga Substitution for Al Atoms Peer-reviewed

    Yoshiki Takagiwa, Takahiko Kamimura, Junpei Tamura Okada, Kaoru Kimura

    JOURNAL OF ELECTRONIC MATERIALS　39　(9)　1885-1889　2010/09

    DOI： 10.1007/s11664-009-1065-z 　

    ISSN： 0361-5235

  66. Surface tension and viscosity of molten vanadium measured with an electrostatic levitation furnace Peer-reviewed

    Junpei T. Okada, Takehiko Ishikawa, Yuki Watanabe, Paul-Francois Paradis

    JOURNAL OF CHEMICAL THERMODYNAMICS　42　(7)　856-859　2010/07

    DOI： 10.1016/j.jct.2010.02.008 　

    ISSN： 0021-9614

  67. Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al2Ru and Ga2Ru Synthesized by Spark Plasma Sintering Process Peer-reviewed

    Yoshiki Takagiwa, Yuka Matsubayashi, Akitoshi Suzumura, Junpei Tamura Okada, Kaoru Kimura

    MATERIALS TRANSACTIONS　51　(5)　988-993　2010/05

    DOI： 10.2320/matertrans.E-M2010807 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  68. Viscosity of liquid boron Peer-reviewed

    Junpei T. Okada, Takehiko Ishikawa, Yuki Watanabe, Paul-Francois Paradis, Yasuhiro Watanabe, Kaoru Kimura

    PHYSICAL REVIEW B　81　(14)　140201　2010/04

    DOI： 10.1103/PhysRevB.81.140201 　

    ISSN： 1098-0121

  69. Volume and enthalpy relaxation in Zr55Cu30Ni5Al10 bulk metallic glass

    O. Haruyama, Y. Nakayama, R. Wada, H. Tokunaga, J. Okada, T. Ishikawa, Y. Yokoyama

    ACTA MATERIALIA　58　(5)　1829-1836　2010/03

    DOI： 10.1016/j.actamat.2009.11.025 　

    ISSN： 1359-6454

    eISSN： 1873-2453

  70. Thermophysical Property Measurements of Liquid Gadolinium by Containerless Methods Peer-reviewed

    T. Ishikawa, J. T. Okada, P. -F. Paradis, Y. Watanabe

    INTERNATIONAL JOURNAL OF THERMOPHYSICS　31　(2)　388-398　2010/02

    DOI： 10.1007/s10765-010-0721-0 　

    ISSN： 0195-928X

  71. Noncontact thermophysical property measurement of liquid cerium by electrostatic levitation Peer-reviewed

    Jianqiang Li, Takehiko Ishikawa, Junpei T. Okada, Yuki Watanabe, Jianding Yu, Shinichi Yoda, Zhangfu Yuan

    JOURNAL OF MATERIALS RESEARCH　24　(7)　2449-2452　2009/07

    DOI： 10.1557/JMR.2009.0278 　

    ISSN： 0884-2914

  72. Volume and viscosity of Zr-Cu-Al glass-forming liquid alloys Peer-reviewed

    Yoshihiko Yokoyama, Takehiko Ishikawa, Junpei T. Okada, Yasuhiro Watanabe, Susumu Nanao, Akihisa Inoue

    JOURNAL OF NON-CRYSTALLINE SOLIDS　355　(4-5)　317-322　2009/02

    DOI： 10.1016/j.jnoncrysol.2008.11.013 　

    ISSN： 0022-3093

  73. Thermoelectric performance of Al-Pd-Mn quasicrystals: comparison with (1/1,2/1-)AlPdMnSi approximants and improvement by Ga substitution for Al Peer-reviewed

    Yoshiki Takagiwa, Takahiko Kamimura, Sizuka Hosoi, Junpei Tamura Okada, Kaoru Kimura

    ZEITSCHRIFT FUR KRISTALLOGRAPHIE　224　(1-2)　21-25　2009

    DOI： 10.1524/zkri.2009.1061 　

    ISSN： 0044-2968

  74. Thermoelectric properties of Al-Pd-Re quasicrystal sintered by Spark Plasma Sintering (SPS): effect of improvement of microstructure Peer-reviewed

    Yoshiki Takagiwa, Takahiko Kamimura, Sizuka Hosoi, Junpei Tamura Okada, Kaoru Kimura

    ZEITSCHRIFT FUR KRISTALLOGRAPHIE　224　(1-2)　79-83　2009

    DOI： 10.1524/zkri.2009.1080 　

    ISSN： 0044-2968

  75. Thermoelectric properties of polygrained icosahedral Al(71-x)Ga(x)Pd(20)Mn(9) (x=0,2,3,4) quasicrystals Peer-reviewed

    Y. Takagiwa, T. Kamimura, S. Hosoi, J. T. Okada, K. Kimura

    JOURNAL OF APPLIED PHYSICS　104　(7)　073721　2008/10

    DOI： 10.1063/1.2990772 　

    ISSN： 0021-8979

  76. Structural vacancies in Al-Pd-Mn quasicrystal and its (1/1,2/1)-AlPdMnSi approximant crystals: Positron lifetime studies Peer-reviewed

    Y. Takagiwa, J. T. Okada, K. Kimura, H. Kitahata, Y. Matsushita, I. Kanazawa

    PHILOSOPHICAL MAGAZINE　88　(13-15)　1929-1934　2008

    DOI： 10.1080/14786430701793911 　

    ISSN： 1478-6435

  77. HAADF-STEM study of B-Mg-Ru approximant crystals Peer-reviewed

    Y. Miyazaki, J. T. Okada, E. Abe, K. Kimura

    PHILOSOPHICAL MAGAZINE　88　(13-15)　1935-1940　2008

    DOI： 10.1080/14786430802339382 　

    ISSN： 1478-6435

  78. High-resolution inelastic X-ray scattering measurements of an Al72Pd20Mn8 alloy above the melting point

    J. T. Okada, M. Inui, D. Ishikawa, S. Tsutsui, A. Q.R. Baron, K. Matsuda, Y. Yokoyama, Y. Watanabe, T. Ishikawa, S. Nanao

    Journal of Non-Crystalline Solids　353　(32-40)　3174-3176　2007/10/15

    DOI： 10.1016/j.jnoncrysol.2007.05.072 　

    ISSN： 0022-3093

  79. Improvement of thermoelectric properties of icosahedral AlPdRe quasicrystals by Fe substitution for Re Peer-reviewed

    Junpei T. Okada, Takehito Hamamatsu, Shizuka Hosoi, Tomohiro Nagata, Kaoru Kimura, Kazuhiro Kirihara

    JOURNAL OF APPLIED PHYSICS　101　(10)　103702　2007/05

    DOI： 10.1063/1.2716212 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  80. The Observation of atomic dynamics in liquid silicon by using inelastic x.ray scattering method coupled with electrostatic levitation method (Liquid structure and transport properties of high temperature metallic Melts)

    MASAKI Tadahiko, ISHIKAWA Takehiko, OKADA Jyunpei T., KOIKE Noriyuki

    JAXA research and development report　6　25-29　2007/03

    Publisher: Japan Aerospace Exploration Agency

    DOI： 10.2322/tastj.12.Ph_25 　

    ISSN： 1349-1113

    More details Close

    The atomic dynamics in high temperature melts are essential information for the understanding of the relation between liquid structure and thermo.physical properties in liquid state. The small electrostatic levitation furnace, ESL, was developed for the inelastic x.ray scattering facility in SPring. 8. The observation of dynamic liquid structure factor, S(Q,w) of normal and undercooled liquid silicon was performed. The phonon peak of S(Q,w) in the liquid silicon was clearly observed and its dispersion relation can be obtained.

  81. Possibility of Al-based Icosahedral Quasicrystal as a Thermoelectric Material

    OKADA Junpei, KIMURA Kaoru

    X-RAYS　49　(1)　85-89　2007/02/27

    Publisher: The Crystallographic Society of Japan

    DOI： 10.5940/jcrsj.49.85 　

    ISSN： 0369-4585

    More details Close

    The thermoelectric properties of icosahedral AlPdRe quasicrystals obtained by replacing Re with transition metals have been studied in according with the guiding principle of Weakly Bonded Rigid Heavy Clusters (WBRHCs) . The dimensionless figure of merit (ZT) was increased 2.6 times from 0.08 to 0.21 by Fe substitution for Re in the icosahedral AIPdRe quasicrystals. It is then possible to improve the thermoelectric performance of i-AlPdRe by searching over a wider range of composition, including the addition of a fourth element or fourth and fifth elements.

  82. Compact electrostatic levitator for diffraction measurements with a two axis diffractometer and a laboratory x-ray source Peer-reviewed

    Tadahiko Masaki, Takehiko Ishikawa, Paul-Francois Paradis, Shinichi Yoda, Junpei T. Okada, Yasuhiro Watanabe, Susumu Nanao, Akiko Ishikura, Kensuke Higuchi, Akitoshi Mizuno, Masato Watanabe, Shinji Kohara

    REVIEW OF SCIENTIFIC INSTRUMENTS　78　(2)　026102　2007/02

    DOI： 10.1063/1.2435590 　

    ISSN： 0034-6748

    eISSN： 1089-7623

  83. New approximant crystals of decagonal B-Mg-Ru quasicrystal Peer-reviewed

    Y. Miyazaki, J. T. Okada, K. Kimura

    PHILOSOPHICAL MAGAZINE　87　(18-21)　2701-2706　2007

    DOI： 10.1080/14786430701361446 　

    ISSN： 1478-6435

  84. Thermophysical properties of the melts of AlPdMn icosahedral quasicrystal Peer-reviewed

    R. Ishikawa, T. Ishikawa, J. T. Okada, T. Maski, Y. Watanabe, S. Nanao

    PHILOSOPHICAL MAGAZINE　87　(18-21)　2965-2971　2007

    DOI： 10.1080/14786430701361347 　

    ISSN： 1478-6435

  85. Dynamics in the melt of an icosahedral Al72Pd20Mn8 quasicrystal Peer-reviewed

    J. T. Okada, M. Inui, D. Ishikawa, A. Q. R. Baron, K. Matsuda, S. Tsutsui, Y. Watanabe, S. Nanao, T. Ishikawa

    JOURNAL OF PHYSICS-CONDENSED MATTER　18　(49)　L613-L618　2006/12

    DOI： 10.1088/0953-8984/18/49/L03 　

    ISSN： 0953-8984

  86. A Compton scattering study on the Hume-Rothery mechanism of AlCu-TM (TM : transition metal) quasicrystals Peer-reviewed

    J. T. Okada, Y. Sakurai, Y. Watanabe, R. Ishikawa, Y. Yokoyama, N. Hiraoka, M. Itou, S. Nanao

    JOURNAL OF PHYSICS-CONDENSED MATTER　18　(31)　7203-7208　2006/08

    DOI： 10.1088/0953-8984/18/31/015 　

    ISSN： 0953-8984

  87. Thermoelectric properties of icosahedral cluster solids - Metallic-covalent bonding conversion and weakly bonded rigid heavy clusters Peer-reviewed

    Kimura, Kaoru, Okada, Junpei T., Kim, Hongki, Hamamatsu, Takehito, Nagata, Tomobiro, Kirihara, Kazuhiro

    MATERIALS AND TECHNOLOGIES FOR DIRECT THERMAL-TO-ELECTRIC ENERGY CONVERSION　886　231-+　2006

    ISSN： 0272-9172

  88. Electron momentum distribution of icosahedral Cd84Yb16 studied by Compton scattering Peer-reviewed

    JT Okada, Y Watanabe, S Nanao, R Tamura, S Takeuchi, Y Yokoyama, N Hiraoka, M Itou, Y Sakurai

    PHYSICAL REVIEW B　68　(13)　132204　2003/10

    DOI： 10.1103/PhysRevB.68.1322204 　

    ISSN： 1098-0121

  89. Resonant fluorescence emission of MnK beta in quasicrystals Peer-reviewed

    Y Watanabe, JT Okada, H Shoji, S Nanao

    JOURNAL OF ALLOYS AND COMPOUNDS　342　(1-2)　422-426　2002/08

    DOI： 10.1016/S0925-8388(02)00853-8 　

    ISSN： 0925-8388

  90. Observation of a pseudogap in alpha-AlMnSi by break-junction tunneling spectroscopy Peer-reviewed

    JT Okada, T Ekino, T Takasaki, Y Yokoyama, Y Watanabe, H Fujii, S Nanao

    JOURNAL OF NON-CRYSTALLINE SOLIDS　312-14　513-516　2002

    DOI： 10.1016/S0022-3093(02)01734-9 　

    ISSN： 0022-3093

  91. Electron momentum distribution of decagonal Al72Ni12Co16 studied by Compton scattering Peer-reviewed

    JT Okada, Y Watanabe, Y Yokoyama, N Hiraoka, M Itou, Y Sakurai, S Nanao

    JOURNAL OF PHYSICS-CONDENSED MATTER　14　(2)　L43-L48　2002/01

    DOI： 10.1088/0953-8984/14/2/102 　

    ISSN： 0953-8984

Show all ︎Show first 5

Misc. 59

  1. 液体Siの超過冷却状態において生じる準安定相間の一次相転移—A First-Order Phase Transition between Metastable Phases Occurring in the Supercooled Liquid Si

    岡田 純平

    日本物理学会誌 = Butsuri　78　(2)　85-90　2023/02

    Publisher: 日本物理学会

    ISSN： 0029-0181

  2. 同素体の化学(3)高校では習わないホウ素とケイ素の同素体 : 液体Bと液体Siの性質

    岡田 純平

    化学と教育 = Chemistry & education　70　(9)　口絵28,442-445　2022

    Publisher: 日本化学会

    ISSN： 0386-2151

  3. ホウ素融体のコンプトン散乱測定 －高温融体の結合の可視化ー

    岡田純平, 石川毅彦, 木村薫

    SPring-8 / SACLA 利用者情報　2015/11

  4. 融けたホウ素は金属なのか？

    岡田純平, 石川毅彦, 木村薫

    化学　70　(10)　12-16　2015/10

    Publisher: 化学同人

    ISSN： 0451-1964

  5. 液体ホウ素は半導体だった －宇宙実験技術を活用した物性測定―

    岡田純平, 石川毅彦

    ISASニュース －宇宙科学の最前線ー　2015/08

  6. Results of Microgravity Experiments Using the Balloon Operated Vehicle with a New Drag-Free Control Method

    KIKUCHI Masao, ISHIKAWA Takehiko, YAMAMOTO Shin, SAWAI Shujiro, MARU Yusuke, SAKAI Shinichiro, BANDO Nobutaka, SHIMIZU Shigehito, KOBAYASHI Hiroaki, YOSHIMITSU Tetsuo, KAN Yuji, MIZUSHIMA Takanari, FUKUYAMA Seijiro, OKADA Junpei, YODA Shinichi, FUKE Hideyuki, KAKEHASHI Yuya, HASHIMOTO Tatsuaki

    International Journal of Microgravity Science and Application (Web)　32　(2)　2015

    ISSN： 2188-9783

  7. Development and Flight Experiment Results of Microgravity Experiment System with One-Directional Drag-Free Control using High Altitude Balloon

    丸祐介, 石川毅彦, 坂東信尚, 澤井秀次郎, 清水成人, 坂井真一郎, 吉光徹雄, 小林弘明, 菊池政雄, 山本信, 福山誠二郎, 岡田純平, 菅勇志, 梯友哉, 福家英之, 伊藤琢博, 水島隆成, 江口光

    日本航空宇宙学会論文集　63　(6)　2015

    ISSN： 1344-6460

  8. F115 Emissivity measurement of high temperature melts combining with an electrostatic levitation method

    Ishikawa Takehiko, Okada Junpei, Watanabe Yuki

    Procee[d]ings of Thermal Engineering Conference　2014　"F115-1"-"F115-2"　2014/11/08

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    Emissivity data is important for the temperature measurement using pyrometer when the sample is processed without container. A spectral emissivity measurement system combined with an electrostatic levitator was developed for high temperature melts. The radiation intensity from a high temperature sample was measured with a multichannel photo spectrometer (MCPD) over the 700 nm to 1000 nm spectral range while a Fourier Transform Infrared Spectrometer (FTIR) measured the radiation over the 1.1μm to 6μm intervals. These spectrometers were calibrated with a black body radiation furnace so that the spectral hemispherical emissivity can be calculated. The experimental results of molten zirconium and niobium are presented.

  9. 大気球を利用した微小重力燃焼実験（実験結果）

    石川 毅彦, 菊池 政雄, 山本 信, 澤井 秀次郎, 丸 祐介, 坂井 真一郎, 坂東 信尚, 清水 成人, 吉光 徹雄, 小林 弘明, 菅 勇志, 水島 隆成, 福山 誠二郎, 岡田 純平, 伊藤 琢博, 梯 友哉, 福家 英之, 橋本 樹明, Ishikawa Takehiko, Kikuchi Masao, Yamamoto Shin, Sawai Shujiro, Maru Yusuke, Sakai Shin-ichiro, Bando Nobutaka, Shimizu Shigehito, Yoshimitsu Tetsuo, Kobayashi Hiroaki, Kan Yuushi, Mizushima Takanari, Fukuyama Seijiro, Okada Junpei, Ito Takahiro, Kakehashi Yuya, Fuke Hideyuki, Hashimoto Tatsuaki

    大気球シンポジウム: 平成26年度 = Balloon Symposium: 2014　2014/11

    Publisher: 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)

    More details Close

    大気球シンポジウム 平成26年度（2014年11月6-7日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 18名資料番号: SA6000021014レポート番号: isas14-sbs-014

  10. 9aBB-3 Compton Scattering Experiments on Extremely High-temperature Liquids

    Okada J. T., Sit P.-L., Watanabe Y., Ishikawa T., Barbiellini B., Bansil A., Kimura V. K., Nanao S.

    Meeting abstracts of the Physical Society of Japan　69　(2)　570-570　2014/08/22

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  11. 27aCB-1 Development of Electrostatic Levitator for Pressurized Atmosphere

    Okada J. T., Ishikawa T., Kumar V., Yokoyama Y., Nanao S.

    Meeting abstracts of the Physical Society of Japan　69　(1)　786-786　2014/03/05

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  12. Droplet Array Combustion Experiment under Microgravity by Using the Balloon Operated Vehicle

    KIKUCHI Masao, ISHIKAWA Takehiko, YAMAMOTO Shin, MARU Yusuke, BANDO Nobutaka, KAN Yuuji, TAZAKI Aya, FUKUYAMA Seijiro, OKADA Junpei, FUKE Hideyuki

    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan (Web)　12　(ists29)　2014

    ISSN： 1884-0485

  13. Development of Electrostatic Levitator for Pressurized Atmosphere

    Okada J.T., Ishikawa T., Vijaya Kumar., Imai W., Paradis P.-F.

    Meeting abstracts of the Physical Society of Japan　68　(2)　721-721　2013/08/26

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  14. 26pEP-5 Thermophysical properties of supercooled liquid Si

    Okada J. T., Ishikawa T., Kumar Vijaya, Watanabe Y.

    Meeting abstracts of the Physical Society of Japan　68　(1)　864-864　2013/03/26

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  15. 24aGD-5 Static structure factor and effective pair potential of liquid Niobium

    Masaki Tadahiko, Karasawa Daichi, Ishikawa Takehiko, Okada Jyunpei T., Kohara Shinji

    Meeting abstracts of the Physical Society of Japan　66　(2)　828-828　2011/08/24

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  16. 25aEG-7 Static structure factor and effective pair potential of liquid Niobium

    Masaki Tadahiko, Karasawa Daichi, Ishikawa Takehiko, Okada Jyunpei T., Kohara Shinji

    Meeting abstracts of the Physical Society of Japan　66　(1)　807-807　2011/03/03

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  17. 25aEG-4 Electron Momentum Distribution of Liquid Si : Covalency of Valence Electrons

    Okada J. T., Sit P. -L., Watanabe Y., Ishikawa T., Barbiellini B., Bansil A., Wan R., Masaki T., Itou M., Sakurai Y., Kimura K., Nanao S.

    Meeting abstracts of the Physical Society of Japan　66　(1)　806-806　2011/03/03

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  18. Hybrid processing combining electrostatic levitation and laser heating: Application to terrestrial analogues of asteroid materials

    Paul-François Paradis, Takehiko Ishikawa, Yuki Watanabe, Junpei Okada

    Advances in Optical Technologies　2011

    DOI： 10.1155/2011/454829 　

    ISSN： 1687-6393 1687-6407

  19. Improvement of position detectors for the electrostatic levitator and measurements of liquid properties of reference liquids

    NORO Makoto, ISHIKAWA Takehiko, OKADA Jyunpei T., MASAKI Tadahiko

    31　273-275　2010/11/17

    ISSN： 0911-1743

  20. THERMOPHYSICAL PROPERTIES MEASUREMENTS OF MOLTEN Si-Ge ALLOYS BY USING ELECTROSTATIC LEVITATION METHOD

    ISHIKITA Yasuyuki, ISHIKAWA Takehiko, OKADA Jyunpei T., MASAKI Tadahiko

    31　270-272　2010/11/17

    ISSN： 0911-1743

  21. THERMOPHYSICAL PROPERTY MEASUREMENTS OF HIGH TEMPERATURE MELTS USING AN ELECTROSTATIC LEVITATION METHOD

    ISHIKAWA Takehiko, OKADA Jumpei T., PARADIS P.-F., WATANABE Yuki

    31　82-84　2010/11/17

    ISSN： 0911-1743

  22. Thermophysical property measurements of Nb-Ni alloy using an Electrostatic Levitation Method

    WATANABE Yuki, OKADA Junpei, ISHIKAWA Takehiko, ITAMI Toshio

    31　88-90　2010/11/17

    ISSN： 0911-1743

  23. Developments of fundamental techniques of the electrostatic levitator for the structural analysis by the x-ray scattering method

    MASAKI Tadahiko, NORO Makoto, SATO Tatsuya, YAMASHITA Yoshihiro, OKADA Jyunpei T., ISHIKAWA Takehiko

    JASMA　27　(4)　227-232　2010/10/30

    Publisher: 日本マイクログラビティ応用学会

    ISSN： 0915-3616

  24. Development of The Electrostatic Levitation Furnace (ELF) for the International Space Station (ISS)

    ISHIKAWA Takehiko, OKADA Junpei T., MURAKAMI Keiji, OGAWA Shiho, KOSHIKAWA Naokiyo, SHIBASAKI Koichi, YAMAURA Yukiko, TAKADA Tetsuya

    JASMA　27　(4)　199-204　2010/10/30

    Publisher: 日本マイクログラビティ応用学会

    ISSN： 0915-3616

  25. Viscosity Measurements of Liquid Boron Using Electrostatic Levitator

    OKADA Junpei T., ISHIKAWA Takehiko, WATANABE Yuki, PARADIS Paul-Francois, WAATANABE Yasuhiro, KIMURA Kaoru

    JASMA　27　(4)　205-209　2010/10/30

    Publisher: 日本マイクログラビティ応用学会

    ISSN： 0915-3616

  26. 26aXA-8 Static structure factor and effective pair potential of liquid Niobium

    Masaki Tadahiko, Iizuka Keisuke, Ishikawa Takehiko, Okada Jyunpei T., Kohara Shinji

    Meeting abstracts of the Physical Society of Japan　65　(2)　768-768　2010/08/18

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  27. Quasicrystalline tenfold symmetry order in boron compounds

    Yoshinobu Miyazaki, Junpei Okada, Eiji Abe, Yoshihiko Yokoyama, Kaoru Kimura

    Journal of the Physical Society of Japan　79　(7)　73601-073601-4　2010/07/01

    Publisher: The Physical Society of Japan

    DOI： 10.1143/JPSJ.79.073601 　

    ISSN： 0031-9015

  28. 23aHY-8 Supercooling and homoneous nucleation of liquid metals and alloys

    Itami Toshio, Okada Junpei, Watanabe Yuki, Ishikawa Takehiko, Yoda Sinichi

    Meeting abstracts of the Physical Society of Japan　65　(1)　846-846　2010/03/01

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  29. Thermophysical Properties Measurements of Molten Vanadium Using an Electrostatic Levitation Furnace

    WATANABE Yuki, OKADA Junpei, ISHIKAWA Takehiko

    26　(4)　349-349　2009/10/19

    ISSN： 0915-3616

  30. Electrostatic Levitation Furnace for the International Space Station

    ISHIKAWA Takehiko, OKADA Junpei T., OGAWA Shiho, MURAKAMI Keiji

    26　(4)　348-348　2009/10/19

    ISSN： 0915-3616

  31. The Study of Supercooling of Liquid Metals and Alloys by Using the Electrostatic Levitation Technique

    ITAMI Toshio, OKADA Junpei, WATANABE Yuki, ISHIKAWA Takehiko, YODA Sinichi

    26　(4)　365-365　2009/10/19

    ISSN： 0915-3616

  32. 26pRE-7 Structural and physical properties of cluster liquids : Icosahedral quasicrystals and icosahedral boron

    Okada Junpei T.

    Meeting abstracts of the Physical Society of Japan　64　(2)　704-704　2009/08/18

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  33. 27aYB-3 Experimental dynamic structure factors of undercooled liquid silicon

    Masaki Tadahiko, Okada Jyunpei, Ishikawa Takehiko, Ishikawa Daisuke, Baron A. Q.

    Meeting abstracts of the Physical Society of Japan　64　(2)　713-713　2009/08/18

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  34. 27aYB-2 Anomaly of physical properties of eutectic liquid alloys and supercoling tendency

    Itami Toshio, Okada Junpei, Watanabe Yuki, Ishikawa Takehiko, Yoda Sinichi

    Meeting abstracts of the Physical Society of Japan　64　(2)　713-713　2009/08/18

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  35. Supercooling Behavior of Liquid Eutectic Alloys

    ITAMI Toshio, OKADA Junpei, ISHIKAWA Takehiko, YODA Sinichi

    25　(4)　789-789　2008/10/30

    ISSN： 0915-3616

  36. Thermophysical Property Measurements of Molten Lutetium and Gadolinium with an Electrostatic Levitator

    WATANABE Yuki, OKADA Junpei, ISHIKAWA Takehiko

    25　(4)　788-788　2008/10/30

    ISSN： 0915-3616

  37. Surface tension and viscosity of liquid boron

    OKADA J. T., ISHIKAWA T., YODA S., WATANABE Y., WATANABE Y., HAMAISHI M., KIMURA K., NANAO S.

    25　(4)　781-781　2008/10/30

    ISSN： 0915-3616

  38. THERMOPHYSICAL PROPERTY MEASUREMENTS OF MOLTEN LUTETIUM AND GADOLINIUM WITH AN ELECTROSTATIC LEVITATOR

    WATANABE Yuki, OKADA Junpei, ISHIKAWA Takehiko

    29　396-398　2008/10/08

    ISSN： 0911-1743

  39. 21pYJ-6 X-ray diffraction measurement of AlCuFe melt using Electrostatic Levitation method

    Hamaishi Mitsuhiro, Watanabe Yasuhiro, Nanao Susumu, Okada Junpei T., Toyokawa Hidenori

    Meeting abstracts of the Physical Society of Japan　63　(2)　706-706　2008/08/25

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  40. 23pYJ-6 Experimental dynamic structure factors of undercooled liquid silicon

    Masaki Tadahiko, Okada Jyunpei, Ishikawa Takehiko, Ishikawa Daisuke, Baron A.Q.

    Meeting abstracts of the Physical Society of Japan　63　(2)　724-724　2008/08/25

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  41. 20pYJ-10 Thermoelectric properties of icosahedral Al-Pd-TM(TM: Mn, Re) quasicrystals

    Takagiwa Y., Kamimura T., Okada J. T., Kimura K.

    Meeting abstracts of the Physical Society of Japan　63　(2)　696-696　2008/08/25

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  42. 24aXP-3 Electrical properties of Al-Pd-Mn quasicrystals and their (1/1, 2/1-)AlPdMnSi approximant crystals : effect of Ga substitution for Al atoms

    Takagiwa Y., Kamimura T., Hosoi S., Okada J. T., Kimura K.

    Meeting abstracts of the Physical Society of Japan　62　(2)　834-834　2007/08/21

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  43. 24pXP-3 Aperiodic Structure with Tenfold Symmetry in Rapidly Quenched BRuTi Alloy.

    Miyazaki Y., Okada J. T., Abe E., Yokoyama Y., Kimura K.

    Meeting abstracts of the Physical Society of Japan　62　(2)　840-840　2007/08/21

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  44. Electrostatic levitation furnace for x.ray diffraction measurements of high.temperature liquid materials (Liquid structure and transport properties of high temperature metallic Melts)

    MASAKI Tadahiko, ISHIKAWA Takehiko, PARADIS Paul.Francois, YODA Shinichi, OKADA Junpei T., WATANABE Yasuhiro, NANAO Susumu, ISHIKURA Akiko, HIGUCHI Kensuke, MIZUNO Akitoshi, WATANABE Masahito, KOHARA Shinji

    JAXA research and development report　6　13-23　2007/03

    Publisher: Japan Aerospace Exploration Agency

    ISSN： 1349-1113

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    An electrostatic levitator was developed for the structural analysis of high.temperature and undercooled liquids by x.ray diffraction. The apparatus can be used to investigate the structure of metallic, semiconductor, and ceramic liquids. Samples of zirconium, silicon, and alumina in their liquid phases could be kept levitated for more than one hour with this apparatus. This was sufficiently long to perform a detailed analysis of the liquid structure by x.ray diffraction techniques.

  45. 20aRF-4 Study of vacancy sites in Al-Pd-Mn quasicrystal and its AIPdMnSi approximant crystals by positron annihilation spectroscopy

    Takagiwa Y., Hidaka S., Okada J. T., Kimura K., Kitahata H., Matsushita Y., Kanazawa I.

    Meeting abstracts of the Physical Society of Japan　62　(1)　792-792　2007/02/28

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  46. 20aRF-5 静電浮遊法および放射光を利用したi-AlPdMnの液体状態に関する研究(準結晶,領域6,金属,超低温,超伝導・密度波)

    石川 亮, 正木 匡彦, 岡田 純平, 渡辺 康裕, 石川 毅彦, 七尾 進

    日本物理学会講演概要集　62　(1)　792-792　2007/02/28

    Publisher: 一般社団法人日本物理学会

    ISSN： 1342-8349

  47. 20aRF-2 Production and Structrue Analysis of New B-Mg-Ru Approximants

    Miyazaki Y., Okada J. T., Abe E., Kimura K.

    Meeting abstracts of the Physical Society of Japan　62　(1)　792-792　2007/02/28

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  48. 23pYP-11 静電浮遊法を用いたAl-Pd-Mn融体の熱物性測定(23pYP 準結晶,領域6(金属,超低温,超伝導・密度波))

    石川 亮, 石川 毅彦, 岡田 純平, 正木 匡彦, 渡辺 康裕, 七尾 進

    日本物理学会講演概要集　61　(2)　636-636　2006/08/18

    Publisher: 一般社団法人日本物理学会

    ISSN： 1342-8349

  49. 23pYP-13 An isotropy in decagonal Al-Mn-Fe-Ge phase by means of Compton scattering method

    Watanabe Yasuhiro, Nanao Susumu, Okada Junpei T.

    Meeting abstracts of the Physical Society of Japan　61　(2)　636-636　2006/08/18

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  50. 29pXE-1 Effective pair potential and transport properties of liquid zirconium

    Masaki Tadahiko, Ishikawa Takehiko, Yoda Shinichi, Nanao Susumu, Okada Jyunpei T., Watanabe Masahito, Ishikura Akiko, Kohara Shinji, Ishikawa Tetsuya

    Meeting abstracts of the Physical Society of Japan　61　(1)　782-782　2006/03/04

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  51. 28aRC-11 The visualization of the peculiar chemical bonds of group III elements

    Hosoi S., Okada J.T., Kimura K., Kato K., Takata M.

    Meeting abstracts of the Physical Society of Japan　61　(1)　824-824　2006/03/04

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  52. 19pYK-4 Magnetic anisotropy in Al-Nn-Fe-Ge decagonal phase measured by Compton Scattering

    Watanabe Y., Nanao S., Yamada T., Okada J. T.

    Meeting abstracts of the Physical Society of Japan　60　(2)　635-635　2005/08/19

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  53. 21aYK-10 Static structure of undercooled liquid zirconium II

    Masaki Tadahiko, Ishikawa Takehiko, Okada Jyunpei T., Nanao Susumu, Watanabe Masahito, Ishikura Akiko, Kohara Shinji, Ishikawa Tetsuya, Yoda Shinichi

    Meeting abstracts of the Physical Society of Japan　60　(2)　654-654　2005/08/19

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  54. 22pXA-5 Electron density distributions ofβ-rhombohedral boron

    Hosoi S., Kim H. K., Okada J. T., Kirihara K., Soga K., Kimura K., Kato K., Takata M.

    Meeting abstracts of the Physical Society of Japan　60　(2)　721-721　2005/08/19

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  55. 25aYQ-10High-resolution inelastic x-ray scattering experiments for liquid Se

    Inui M., Hosokawa S., Matsuda K., Naito Y., Okada J., Ishikawa D., Katayama Y., Tsutsui S., Baron A.Q.R.

    Meeting abstracts of the Physical Society of Japan　60　(1)　741-741　2005/03/04

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  56. 24pYQ-5 Static structure of undercooled liquid zirconium

    Masaki Tadahiko, Ishikawa Takehiko, Okada Jyunpei T, Nanao Susumu, Watanabe Masahito, Mizuno Akitoshi, Higuchi Kensuke, Ishikawa Tetsuya, Yoda Shinichi

    Meeting abstracts of the Physical Society of Japan　60　(1)　734-734　2005/03/04

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  57. Magnetic Compton Scattering of d-AlMnFeGe alloy

    Watanabe Y., Sakurai Y., Itoh M., Okada J. T., Nanao S.

    Meeting abstracts of the Physical Society of Japan　58　(2)　716-716　2003/08/15

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  58. Magnetic Compton Scattering Study of UGe_2 II

    Sakurai Y., Itou M., Okada J., Nanao S., Yamamoto E., Haga Y., Onuki Y.

    Meeting abstracts of the Physical Society of Japan　58　(2)　474-474　2003/08/15

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  59. X-ray magnetic circular dichroism in quasicrystals

    Yasuhiro Watanabe, Junpei Tamura, Hironobu Shoji, Susumu Nanao, Tetsuya Nakamura, Yoshihiko Yokoyama

    Materials Science and Engineering A　294　(296)　617-620　2000

    DOI： 10.1016/S0921-5093(00)01103-5 　

Show all ︎Show first 5

Presentations 4

  1. エキゾチック共晶合金の発見 Invited

    岡田純平

    日本材料学会金属ガラス部門委員会　2023/11/01

  2. 超高温液体の物性

    日本化学会年会　2016/03/26

  3. 冶金学的手法を用いた新しいアモルファスシリコン創製への挑戦

    元素戦略/希少金属代替材料開発 第10回合同シンポジウム　2016/02/23

  4. Bonding Characteristics of High Temperature Liquids Studied by Electrostatic Levitator

    ISPS－６　2015/09/14

Industrial Property Rights 1

  1. 多孔質アモルファスシリコン、多孔質アモルファスシリコンの製造方法及び二次電池

    特許6896261

    Property Type: Patent

Research Projects 14

  1. アモルファス材料表面における構造的不均一性に関する研究

    中山 幸仁, 岡田 純平

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(C)

    Institution: 東北大学

    2021/04/01 - 2024/03/31

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    ガラスやアモルファス材料の原子配列は、数学的なランダムではなく局所的な凝集を起因とする不均一性が発現することが示唆されている。この構造的な不均一性を解明するため、これまでX線や中性子回折法を用いた研究が精力的に進められてきた。ところが、これらの回折法では実験データに基づくモデリングにより進められており、原子スケールの局所的な構造的不均一性を評価することは困難である。一方、走査トンネル顕微鏡(STM)は、実空間において表面原子配列を原子スケールで観測することができるので、アモルファス表面の原子座標データを近似なしに取得することが可能である。これにより、原子の座標データが求められ原子間距離や動径分布関数(PDF)が導出できる。更に、これらの座標データに対してクラスター解析法を適用して定量的な指標として活用することができれば、アモルファス/ガラスの原子配列の中に秩序を見出せる可能性がある。 本研究は以下の３項目の達成を目指して研究を推進している。 ①アモルファス表面原子構造を形成する急冷Si(111)表面に対してSTM観測を実施して原子座標データを取得する。また、クラスター解析法は、非階層的手法であるk平均法を検討すると共に、階層的手法である凝集型階層クラスタリングを適応させて解析を進める。 ②実験から得られた実空間データから原子間距離を算出し、定量分析の指標となるPDF解析法を活用するためのプロトコルを確立する。 ③アモルファス中の原子クラスター形成を念頭におき、構造的不均一性発現の条件をPDFやクラスター解析法により見出せるか検証を行う。特に、Si(111)表面においては急冷条件を変化させることにより不均一性の発現条件を見出す。

  2. Development of fabrication process of a-Si by liquid quenching for mass production

    OKADA JUNPEI

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2018/04/01 - 2021/03/31

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    Amorphous Si, which is widely used as a base material for solar cells, is currently available in thin film form made by chemical vapor deposition. If amorphous Si can be obtained in large quantities by liquid quenching, like many other amorphous metals, the range of applications is expected to further expand. However, despite many previous attempts, it has not been possible to obtain bulk amorphous Si directly from liquid Si. In this study, we succeeded in producing amorphous Si by liquid quenching using the single-roll method.

  3. Production of a-Si from supercooled liquid Si

    OKADA JUNPEI

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Young Scientists (A)

    2014/04/01 - 2017/03/31

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    Amorphous (a-) silicon (Si) is an important semiconductor used for thin film transistors and solar panels. In 1975, Spear et al. demonstrated that thin films of a-Si deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD) from silane (SiH4) are useful for semiconductor devices, which constitutes a breakthrough for a-Si applications1. On the other hand, it has long been challenged to obtain a “bulk” a-Si from liquid (l-) Si. However, all attempts have failed so far. In this research project, we tried to produce bulk a-Si directly from supercooled l-Si. Combining an electrostatic levitator with a quenching system, we quenched supercooled l-Si at 300 K below the melting temperature to obtain bulk a-Si.

  4. Study on Particle Temperatures and Defects in Self-Organized Coulomb Crystals

    ADACHI Satoshi, OKADA Junpei

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Japan Aerospace EXploration Agency

    2013/04/01 - 2016/03/31

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    From velocity distribution of particle motion and wave propagation in the Coulomb crystal, it is found that particle temperature is several times higher than the room temperature. From the dispersion relation of the dust lattice wave (DLW), the ion temperature is obtained and is close to the room temperature. In order to investigate power sources of particle acceleration, the ion energy is estimated by considering ion acceleration caused by the negative potential on the particle surface. The potential profile is obtained by solving the Poisson equation. Thus the ion energy is obtained to be several times higher than the room temperature. Although the electron energy is still higher than the ion energy, the ion energy should be an important power source. A new plasma chamber is developed to suppress a void formation. The shape of Coulomb cloud suggests that the potential profile is much flat as expected. This result will be used for development of a next-generation apparatus.

  5. Surface tension and viscosity measurements of highly viscous melts using drop rotation

    ISHIKAWA Takehiko, OKADA Junpei

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Japan Aerospace Exploration Agency

    2012/04/01 - 2015/03/31

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    Aim of this research is to establish a new method to measure surface tension and viscosity of highly viscous melts combined with containerless techniques. This measreument will be useful for the research of bulk metalic glasses. By employing a high speed camera, bifurcation phenomena from axisymmetric to non-axisymmetric shape were observed on electrostatically levitated rotating drops. It was confirmed that the bifurcation occurs at theoretically predicted rotation rate, and surface tension can be obtained by measureing rotation rate. It was also confirmed that the shape evolution speed after the bifurcation depends on the viscosity of the sample. This result shows a possiblity of quantitative viscosity measurement of highly viscous melts using a drop rotation.

  6. Observation of Fluctuations in deep undercooling liquids and the relation between the fluctuation and the formation of amorphous materials

    TADAHIKO Masaki, MIZUNO Akitoshi, OKADA Jyunpei, MUNEJIRI Shuji

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Shibaura Institute of Technology

    2011/04/01 - 2014/03/31

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    Undercooled liquid state of metals and semiconductors can be observed when the cooling of those molten states. One of the origin of anomalous properties of undercooled liquids might be related to the large fluctuation in liquids, which is derived from the nucleation or the embryo of solid state. In this study, we observed the atomic dynamics in undercooled liquid metals by using the electrostatic levitator and the high resolution inelastic x-ray scattering technique together with the synchrotron radiation facility.

  7. Development of Thermophysical property measurements system for high temperature oxide melts by a pressurized electorstatic levitator

    ISHIKAWA Takehiko, OKADA Junpei, YODA Shin' ichi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Japan Aerospace Exploration Agency

    2009 - 2011

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    The aim of this research is to establish a thermophysical property measurement sysytem for high temperature oxide melts using an electrostatic levitation method. An electrostatic levitator has been developed which can be pressurized up to 10 atomosphere. Then, trials were made to levitate and melt oxide samples with it. Several issues including position sensing problem due to the high pressure gas around the sample and the fractuation of surface charge on the oxide samples made the stable levitation difficult. Thermophysical properties of ZrO_2, the ficnal goal of this research has not been completed yet. We will continue this research to the goal.

  8. Materials Search in Cluster-based Materials Constructed from Group III Elements

    KIMURA Kaoru, KIRIHARA Kazuhiro, SOGA Kohei, OKADA Junpei, TAKAGIWA Yoshiki, HYODO Hiroshi, KANAZAWA Ikuzo

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research on Priority Areas

    Institution: The University of Tokyo

    2007 - 2011

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    We proposed a new guiding principle to improve thermoelectric performance and confirmed the efficiency in Al-based quasicrystals. We discovered self-compensation phenomena for doped-electron in β-rhombohedral and α-tetragonal boron. On the other hand, the self-compensation phenomena did not occur in α-rhombohedral boron and we found superconductive transition by Li-doping.

  9. Covalency of Valence Electrons in Liquid Silicon: A Direct X-ray Compton Scattering Measurement

    OKADA Junpei

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Young Scientists (B)

    Institution: Japan Aerospace Exploration Agency

    2008 - 2009

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    We have measured a Compton profile of liquid silicon with an electrostatic levitator and found that the Compton profile is much the same as that of solid silicon. Despite its metallic nature, the obtained Compton profile is largely different from that of an interacting free-electron gas with the same valence-electron density. Analysis of the Compton profile of liquid Si using Car-Parrinello Molecular Dynamics simulation shows the existence of covalent bonds in liquid silicon, which has been predicted by first-principles molecular dynamics simulation.

  10. Atomic dynamics in the solidification process from the undercooled liquid state

    MASAKI Tadahiko, ISHIKAWA Takehiko, OKADA Jyunpei

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Shibaura Institute of Technology

    2007 - 2009

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    Undercooled liquid state of metals and semiconductors can be observed from those molten states. The novel materials, for example amorphous materials, can be processed from the undercooled liquid state. In this study, we observed undercooled liquid metals from the microscopic points of views by using the electrostatic levitator and high energy x-ray diffraction in the synchrotron radiation facility.

  11. Development of Thermoelectric Materials using Weakly Bonded Rigid Heavy Clusters

    KIMURA Kaoru, OKADA Junpei

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: The University of Tokyo

    2007 - 2009

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    In AlPdRe and AlPdMn quasicrystals, we improved the microstructure and substituted the constitution elements according to our new guiding principle of WBRHC (weakly bonded rigid heavy clusters). We succeeded that the dimensionless figure of merit, ZT, increases 2.6 times to 0,21 by the substitution of Fe for Re in the former and 1.4 times to the largest value of 0.26 for the quaqsicrystals by the substitution of Ga for Al in the latter. On the other hand, in Al_2Ru which has been considered to be a related material for the Al-based quasicrystals, we succeeded to improve ZT to be 0.5 by substituting heavier Ga for Al and decreasing the thermal conductivity.

  12. Development of thermophysical properties measurement system for high temperature melts using an electrostatic levitation method.

    ISHIKAWA Takehiko, YODA Shinichi, OKADA Junpei, MASAKI Tadahiko

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Japan Aerospace Exploration Agency

    2006 - 2008

  13. 四重極イオントラップの多重極化によるボロン・クラスター集合固体の創製

    木村 薫, 岡田 純平, 金山 敏彦

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東京大学

    2005 - 2006

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    EMSIT(多重極イオントラップ)の性能を評価するために、36pole-EMSITを用い、モノシランガスSiH_4を原料に、水素化シリコン・クラスターSi_nH^+_x(n=2-6)の生成を行い、引き出しイールドをEQSIT(四重極イオントラップ)の場合と比較した。EMSIT内で、SiH_4に250evの電子線を照射することでSiH^+_xイオンを生成、捕獲し、これと雰囲気のSiH_4分子との反応によってSi_nH^+_xを合成した。EMSITとEQSITの場合のSi_nH^+_x(n=2-6)イオンビーム電流値を比較した。いずれの場合も、EQSITよりもEMS1Tの方が大きなイールドを供給でき、特に、Si_nH^+_x(n=2,4,5)は、EQSITの場合の9〜10倍のイールドを得た。このように、36pole-EMSITが、シミュレーション通り、EQSITよりも大量のクラスターを供給できるクラスター源として働くことを、実験的に確認できた。 EQSITを用いて、デカボランとジボランから水素化ボロン・クラスターを作製した。質量スペクトルからB_mH_n^+(m=12-22)が生成していた。生成したクラスターの中で、B_<12>H_n^+に関して質量分布の解析を行ったところ、水素の数n=7〜8のクラスターが50%を占めていた。密度汎関数法によるformation energyの計算結果より、実験で生成したB_<12>H_<7,8>^+は正二十面体構造であると予想される。デカボランイオンとジボランからB_<12>H_<12>^+が生じたときのエネルギーを計算したところ、2.2〜3.4eVの発熱反応であることが分かった。B_<12>H_<12>^+からの水素分子脱離プロセスを計算したところ、エネルギーの高い中間状態は存在しなかった。したがって、反応熱によって2つのH_2が放出されB_<12>H_8^+が生成することが予想され、実験結果をよく説明できた。

  14. Study of Undercooled Melt and Solidification Using Synchrotron Radiation and Electrostatic Levitation Technique

    NANAO Susumu, KURIBAYASHI Kazuhiko, WATANABE Masato, YOKOYAMA Yoshihiko, OKADA Junpei, MASAKI Tadahiko

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: University of Tokyo

    2004 - 2006

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    Our project, which is the realization of a compact electrostatic levitator for the measurements using synchrotron radiation and measurements of x-ray diffraction, Compton scattering and high resolution x-ray inelastic scattering at Spring-8 has been fulfilled nearly as planned. (1) X-ray diffraction: High energy x-ray diffraction profiles have been precisely measured for the melts and undercooled melts of Zr, Si and Ba-Ge compunds using electrostatic levitation technique. And their structures were analyzed partly with Monte Carlo simulation. For the melt of icosahedral ALPdMn alloy, the first peak in low angle region has been clearly detected for the first time in the x-ray diffraction profile, which confirms the existence of order structure in the scale of 0.35nm in the melt. (2) Compton scattering and high resolution x-ray inelastic scattering: Compton scattering profiles for Si melt was measured at BLO8W in Spring-8. The analyses of the obtained momentum distribution of valence electrons have demonstrated the existence of covalent bonds for the first time. High resolution x-ray inelastic scattering profiles were measured for Si melt and Si undercooled melt of 1517K, and dynamic structure factor has found clearly different between them. This is the first case in the world that a profile of Compton scattering and/or high resolution x-ray inelastic scattering is successfully measured. The present studies are to be pioneering work that shows it is really possible to study dynamics and electronic structures of high temperature melt and undercooled melt.

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Other 1

  1. 超過冷却液体を用いたナノスケール複合材料の創製

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    静電浮遊法を用いて深く過冷させた高温液体を急冷凍結し、新規準安定相を作製する。