Details of the Researcher

PHOTO

Ayahisa Okawa
Section
Institute of Multidisciplinary Research for Advanced Materials
Job title
Assistant Professor
Degree

  • 博士（工学）（長岡技術科学大学）

Researcher ID
GSD-3778-2022

Research History 5

  • 2022/10 - Present
    Tohoku University　Institute of Multidisciplinary Research for Advanced Materials Center for Exploration of New Inorganic Materials Environmental Inorganic Materials Chemistry　Assistant Professor

  • 2020/02 - 2020/03
    Friedrich-Alexander Universität Erlangen-Nürnberg　Department of Materials Science and Engineering

  • 2017/12 - 2018/02
    Indira Gandhi Centre for Atomic Research　Mechanical Metallurgy Division

  • 2017/09 - 2017/11
    Indian Institute of Technology Madras　Department of Metallurgical and Materials Engineering

  • 2017/02 - 2017/03
    Indian Institute of Technology Madras　Department of Metallurgical and Materials Engineering

Education 4

  • Nagaoka University of Technology　Graduate School of Engineering　Department of Science of Technology Innovation

    2019/10 - 2022/09

  • Nagaoka University of Technology　Graduate School of Engineering　Department of Mechanical Engineering

    2018/04 - 2019/09

  • Nagaoka University of Technology　Faculty of Engineering　Mechanical Engineering

    2016/04 - 2018/03

  • Tomakomai National College of Technology　Mechanical Engineering

    2011/04 - 2016/03

Professional Memberships 2

  • The Ceramic Society of Japan

    2020/04 - Present

  • The American Ceramic Society

    2018/12 - Present

Research Interests 3

  • MAX phases

  • MXene

  • Rare earth

Awards 6

  1. Hatano Scholarship Fund Multidisciplinary Research Award

    2023/12　Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

  2. Student Award

    2022/09　Nagaoka University of Technology

  3. Poster Session: Award of Excellence

    2022/01

  4. Fighting-spirit award

    2020/09　The Ceramic Society of Japan The 33rd Fall Meeting

  5. Best Moderator Award

    2019/11　The 4th International Conference on "Science of Technology Innovation" 2019

  6. The Takeshi Yokota Award

    2019/03　The 10th U3 Material Design Forum

Show all ︎Show 5

Papers 32

  1. Optical characteristics and application of cobalt/nickel doped SrZn2(PO4)2 blue-violet and violet inorganic pigment powders Peer-reviewed

    Qiuyu Cheng, Zhiwei Wang, Ayahisa Okawa, Takuya Hasegawa, Tohru Sekino, Shu Yin

    Advanced Powder Technology　36　(8)　104952-104952　2025/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.apt.2025.104952 　

    ISSN： 0921-8831

  2. Metal-Reduction-Triggered Red Luminescence Quenching in Eu3+-Doped Bi2MoO6 Nanophosphors for H2S Gas Detection Peer-reviewed

    Taisei Hangai, Takuya Hasegawa, Yibei Xue, Ayahisa Okawa, Tom Ichibha, Kenta Hongo, Ryo Maezono, Sun Woog Kim, Tomoyo Goto, Yasushi Sato, Shu Yin

    ACS Applied Nano Materials　2025/06/04

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsanm.5c01752 　

    ISSN： 2574-0970

    eISSN： 2574-0970

  3. Insights into the phase transition behavior of thermochromic VO2 (M1) powders doped with Tungsten Peer-reviewed

    Yibei Xue, Lei Miao, Takuya Hasegawa, Ayahisa Okawa, Tomoyo Goto, Yeongjun Seo, Tohru Sekino, Shu Yin

    Advanced Powder Technology　36　(5)　104857-104857　2025/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.apt.2025.104857 　

    ISSN： 0921-8831

  4. Phosphorus Doping Coupled with Gradient Film Strategy to Achieve Thermochromic Performance Enhancement of VO2 Peer-reviewed

    Yibei Xue, Peng Song, Lei Miao, Takuya Hasegawa, Ayahisa Okawa, Tomoyo Goto, Yeongjun Seo, Ryo Maezono, Tohru Sekino, Shu Yin

    ACS Applied Materials & Interfaces　2025/03/13

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsami.4c19835 　

    ISSN： 1944-8244

    eISSN： 1944-8252

  5. Fabrication of Cs0.33WO3-g-C3N4-rGO nanocomposite for near-infrared shielding and photocatalysis applications Peer-reviewed

    Vinda Puspasari, Qiuyu Jin, Yibei Xue, Ayahisa Okawa, Takuya Hasegawa, Shu Yin

    Applied Surface Science　162983-162983　2025/03

    Publisher: Elsevier BV

    DOI： 10.1016/j.apsusc.2025.162983 　

    ISSN： 0169-4332

  6. Optical Properties of Cobalt/Nickel Doped SrAl12O19 Blue Inorganic Pigments and Their Application in 3YSZ Ceramics Peer-reviewed

    Qiuyu Cheng, Zhiwei Wang, Ayahisa Okawa, Takuya Hasegawa, Yamato Hayashi, Tohru Sekino, Shu Yin

    Journal of Alloys and Compounds　179402-179402　2025/02

    Publisher: Elsevier BV

    DOI： 10.1016/j.jallcom.2025.179402 　

    ISSN： 0925-8388

  7. Optical properties and application of blue and purple inorganic pigment powders based on cobalt/nickel doped Sr2MgSi2O7 Peer-reviewed

    Qiuyu Cheng, Zhiwei Wang, Ayahisa Okawa, Takuya Hasegawa, Tohru Sekino, Shu Yin

    Solid State Sciences　107869-107869　2025/02

    Publisher: Elsevier BV

    DOI： 10.1016/j.solidstatesciences.2025.107869 　

    ISSN： 1293-2558

  8. W/Mo/Cr Doping Modulates the Negative–Positive Inversion Gas Sensing Behavior of VO2(M1) Peer-reviewed

    Lei Miao, Yibei Xue, Peng Song, Takuya Hasegawa, Ayahisa Okawa, Ryo Maezono, Tohru Sekino, Shu Yin

    ACS Sensors　2025/01/09

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acssensors.4c03006 　

    ISSN： 2379-3694

    eISSN： 2379-3694

  9. Synthesis of novel colored substrate-free pearlescent pigments of vanadium phosphates with large-size layered platelet morphology Peer-reviewed

    Qiuyu Cheng, Yibei Xue, Takuya Hasegawa, Ayahisa Okawa, Kizuku Kushimoto, Junya Kano, Tohru Sekino, Shu Yin

    Journal of Alloys and Compounds　1010　177735-177735　2025/01

    Publisher: Elsevier BV

    DOI： 10.1016/j.jallcom.2024.177735 　

    ISSN： 0925-8388

  10. Novel Selectivity: Target of Gas Sensing Defined by Behavior Peer-reviewed

    Lei Miao, Peng Song, Yibei Xue, Zhufeng Hou, Takuya Hasegawa, Ayahisa Okawa, Tomoyo Goto, Yeongjun Seo, Ryo Maezono, Tohru Sekino, Shu Yin

    Advanced Materials　2024/12/19

    Publisher: Wiley

    DOI： 10.1002/adma.202413023 　

    ISSN： 0935-9648

    eISSN： 1521-4095

    More details Close

    Abstract Traditional selectivity of gas sensors determined by the magnitude of the response value has significant limitations. The distinctive inversion sensing behavior not only defies the traditional sensing theory but also provides insight into defining selectivity. Herein, the novel definition of selectivity is established in a study with VO2(M1). The sensing behavior of VO2(M1) is investigated after its synthesis conditions optimization by machine learning. In gases of the same nature, VO2(M1) shows remarkably selective for NH3 marked with unique resistance increase behavior. Such anomalous behavior is attributed to the formation of the Schottky junction between VO2(M1) and the electrode. The “work function‐electron affinity” relation is summarized as the selectivity coefficient, a parameter for predicting the selectivity of the sensing material effectively.

  11. Coloring properties of blue inorganic pigments based on cobalt/nickel doped strontium magnesium β-alumina structure in 3YSZ ceramics Peer-reviewed

    Qiuyu Cheng, Ayahisa Okawa, Takuya Hasegawa, Yamato Hayashi, Tohru Sekino, Shu Yin

    Ceramics International　50　(24)　53580-53591　2024/12/15

    Publisher: Elsevier BV

    DOI： 10.1016/j.ceramint.2024.10.208 　

    ISSN： 0272-8842

  12. Luminescence Tuning of NIR Luminescence Nanophosphor Bi3+/Yb3+-Doped RE2MoO6 (RE = Gd, Y, and Lu) and Gd2Mo1–xWxO6 Peer-reviewed

    Taisei Hangai, Takuya Hasegawa, Jian Xu, Takayuki Nakanishi, Takashi Takeda, Tomoyo Goto, Yasushi Sato, Ayahisa Okawa, Shu Yin

    The Journal of Physical Chemistry C　2024/11/15

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.jpcc.4c04814 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  13. Control of Particle Morphology and Orientation in Rare-Earth Layered Molybdate Phosphors Particles Invited

    Takuya Hasegawa, Suzuka Noda, Ayahisa Okawa, Shu Yin

    Journal of the Society of Powder Technology, Japan　61　(11)　687-693　2024/11/10

    Publisher: The Society of Powder Technology, Japan

    DOI： 10.4164/sptj.61.687 　

    ISSN： 0386-6157

    eISSN： 1883-7239

  14. One-pot facile synthesis of rod-like Bi2S3 particle in deep eutectic solvent and its ppb-level selective H2S gas detection Peer-reviewed

    Reiko Furukawa, Takuya Hasegawa, Ayahisa Okawa, Shu Yin

    Dalton Transactions　2024/11/05

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d4dt03006k 　

    ISSN： 1477-9226

    eISSN： 1477-9234

    More details Close

    Bismuth sulfide, Bi2S3, was prepared by a one-pot reaction using various choline chloride-based deep eutectic solvents (DESs) as the reaction field. Rod-like particles obtained with acetamide-thioacetamide-based DESs were found to...

  15. Unveiling the NIR modulation performance enhancement of VO2 endowed by oxygen vacancy elimination Peer-reviewed

    Yibei Xue, Lei Miao, Peng Song, Takuya Hasegawa, Ayahisa Okawa, Ryo Maezono, Tohru Sekino, Shu Yin

    Solar Energy Materials and Solar Cells　274　113007-113007　2024/08/15

    Publisher: Elsevier BV

    DOI： 10.1016/j.solmat.2024.113007 　

    ISSN： 0927-0248

  16. Er3+/Tm3+ co-doped Zr0.85Y0.15O1.925:Yb3+ phosphors: dual-mode ratiometric thermometry based on near infrared up-conversion/down-shifting photoluminescence Peer-reviewed

    Takuya Hasegawa, Yuki Takahashi, Tomoyo Goto, Yasushi Sato, Ayahisa Okawa, Shu Yin

    Dalton Transactions　53　(32)　13617-13627　2024/06/25

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d4dt01972e 　

    ISSN： 1477-9226

    eISSN： 1477-9234

    More details Close

    This study develops Er3+/Tm3+ co-doped Zr0.85Y0.15O1.925:Yb3+ phosphors for dual-mode ratiometric thermometry, highlighting significant temperature-dependent NIR luminescence variations and anti-thermal quenching.

  17. Uncovering the distinctive phase transition characteristics and thermochromic performance of VO2 with different N-doping sites Peer-reviewed

    Yibei Xue, Lei Miao, Takuya Hasegawa, Ayahisa Okawa, Shunya Yoshino, Hideki Kato, Masato Kakihana, Shu Yin

    Applied Surface Science　657　159779-159779　2024/06/01

    Publisher: Elsevier BV

    DOI： 10.1016/j.apsusc.2024.159779 　

    ISSN： 0169-4332

  18. High-temperature corrosion of sintered RE2Si2O7 (RE = Yb and Ho) environmental barrier coating materials by volcanic ash Peer-reviewed

    Ayahisa Okawa, Son Thanh Nguyen, Tadachika Nakayama, Thi-Mai-Dung Do, Hisayuki Suematsu, Shu Yin, Takuya Hasegawa, Tsuneo Suzuki, Takashi Goto, Koichi Niihara

    International Journal of Minerals, Metallurgy and Materials　31　(7)　1628-1638　2024/05/28

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s12613-024-2899-3 　

    ISSN： 1674-4799

    eISSN： 1869-103X

  19. Elucidation of Structural Features and Photoluminescence Properties for Hydrothermally-synthesized γ-KEu(MoO4)2 Microcrystal Phosphor with Metastable Orthorhombic Structure and Differences of Luminescence Properties by Structure Transition Due to Y3+-dilution Peer-reviewed

    Takuya Hasegawa, Suzuka Noda, Wataru Hikita, Kenji Toda, Ayahisa Okawa, Shu Yin

    New Journal of Chemistry　2024/04/05

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d3nj05866b 　

    ISSN： 1144-0546

    eISSN： 1369-9261

    More details Close

    Potassium europium molybdate, KEu(MoO4)2,is an intriguing material known for its efficient luminescence properties attributed to Eu3+ ions and its polymorphic nature. Despite its significance, research on the metastable γ-phase has...

  20. Acquisition of Emissive Single-Crystalline AEu(MoO4)2 (A = Na, K, Rb, and Cs) Double Molybdates by One-Pot Hydrothermal Synthesis: Relationship between Particle Morphology and Photoluminescence Properties Peer-reviewed

    Suzuka Noda, Takuya Hasegawa, Tomoyo Goto, Yasushi Sato, Ayahisa Okawa, Shu Yin

    Crystal Growth & Design　2024/04/04

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.cgd.4c00332 　

    ISSN： 1528-7483

    eISSN： 1528-7505

  21. Self-healing ability and full strength recovery at medium temperatures of low content titanium carbide/alumina composites Peer-reviewed

    Son Thanh Nguyen, Ayashisa Okawa, Thi-Mai-Dung Do, Chu Minh Ngo, Tsuyoshi Takahashi, Tadachika Nakayama, Hisayuki Suematsu, Koichi Niihara

    Journal of the Ceramic Society of Japan　132　(3)　85-92　2024/03/01

    Publisher: Ceramic Society of Japan

    DOI： 10.2109/jcersj2.23176 　

    ISSN： 1882-0743

    eISSN： 1348-6535

  22. Key Role of Metal-to-Metal Charge Transfer Transition between Mo6+ and Bi3+ for Enhancement in NIR Luminescence of Gd2MoO6:Bi,Yb Nanophosphor Peer-reviewed

    Taisei Hangai, Takuya Hasegawa, Jian Xu, Takayuki Nakanishi, Takashi Takeda, Kosuke Nakano, Kenta Hongo, Ryo Maezono, Tomoyo Goto, Yasushi Sato, Ayahisa Okawa, Shu Yin

    The Journal of Physical Chemistry C　2024/02/15

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.jpcc.3c07501 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  23. Development of Silicates and Spraying Techniques for Environmental Barrier Coatings Peer-reviewed

    Ayahisa Okawa, Son Thanh Nguyen, Tadachika Nakayama, Hisayuki Suematsu, Takashi Goto, Koichi Niihara

    Ceramic Coatings for High-Temperature Environments　283-312　2023/12/06

    Publisher: Springer International Publishing

    DOI： 10.1007/978-3-031-40809-0_9 　

    ISSN： 1612-1317

    eISSN： 1868-1212

  24. Photoluminescence/Optical-absorption modulation of layered lanthanide molybdates for chemical sensing of reductive materials Peer-reviewed

    Takuya Hasegawa, Yuzuki Kanaoka, Suzuka Noda, Ayahisa Okawa, Shu Yin

    Chemistry Letters　2023/12/05

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/chemle/upad005 　

    ISSN： 0366-7022

    eISSN： 1348-0715

    More details Close

    Abstract This work have found K1-δHδEu(MoO4)2 as a novel material for detecting reducing agents. The red emission from Eu3+ was notably diminished in the presence of the reducing agent, followed by its restoration in the presence of the oxidizing agent, demonstrating a significant luminescence modulation. This effect is believed to be induced by polaron absorption between Mo5+ and Mo6+, deactivating the red luminescence of Eu3+. Notably, the facile proton deinsertion stemming from the layered structure contributed to its exceptional restoration capability.

  25. Self-healing ceramic coatings Peer-reviewed

    Son Thanh Nguyen, Ayahisa Okawa, Tadachika Nakayama, Hisayuki Suematsu

    Advanced Ceramic Coatings　107-136　2023/06

    Publisher: Elsevier

    DOI： 10.1016/b978-0-323-99659-4.00011-5 　

  26. Gas sensing performance of Nb2CTx synthesized by hydrothermal assisted in-situ HF generation etching method Peer-reviewed

    Ayahisa Okawa, Mingyang Yang, Takuya Hasegawa, Tadaharu Ueda, Sunghun Cho, Tohru Sekino, Shu Yin

    3　(1)　2023/05

    DOI： 10.1007/s43939-023-00048-4 　

  27. Liquid-phase oxidation synthesis of WS2 –WO3 particles with enhanced gas sensing performance Peer-reviewed

    Chinatsu Yoshizawa, Takuya Hasegawa, Ayahisa Okawa, Shu Yin

    Functional Materials Letters　16　(01)　2023/01

    Publisher: World Scientific Pub Co Pte Ltd

    DOI： 10.1142/s1793604723400015 　

    ISSN： 1793-6047

    eISSN： 1793-7213

    More details Close

    In this study, [Formula: see text] particles were successfully synthesized by a solvothermal liquid-phase oxidation process under various conditions and their gas sensing performance was evaluated at room temperature. The sample synthesized in ethanol-rich solvent at 210[Formula: see text]C showed excellent gas sensing performance. It is suggested that the crystalline phase and the particle morphology, which are essential for improving gas sensing performance, are effectively controllable by the present liquid phase oxidation process.

  28. Self-healing ability, strength enhancement, and high-temperature oxidation behavior of silicon carbide-dispersed ytterbium disilicate composite for environmental barrier coatings under isothermal heat treatment Peer-reviewed

    A. Okawa, S.T. Nguyen, J.P. Wiff, H.-W. Son, T. Nakayama, H. Hashimoto, T. Sekino, T.M.D. Do, H. Suematsu, T. Suzuki, T. Goto, K. Niihara

    Journal of the European Ceramic Society　42　(13)　6170-6181　2022/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.jeurceramsoc.2022.05.057 　

    ISSN： 0955-2219

  29. Autonomous crack healing ability of SiC dispersed Yb2Si2O7 by oxidations in air and water vapor Peer-reviewed

    A. Okawa, S.T. Nguyen, J.P. Wiff, H.-W. Son, T. Nakayama, T.M.D. Do, H. Suematsu, T. Suzuki, T. Goto, K. Niihara

    Ceramics International　47　(24)　34802-34809　2021/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.ceramint.2021.09.020 　

    ISSN： 0272-8842

  30. Titanium Nitride and Yttrium Titanate Nanocomposites, Endowed with Renewable Self-Healing Ability Peer-reviewed

    Son Thanh Nguyen, Ayahisa Okawa, Hirokazu Iwasawa, Tadachika Nakayama, Hideki Hashimoto, Tohru Sekino, Hisayuki Suematsu, Koichi Niihara

    Advanced Materials Interfaces　8　(22)　2170126-2170126　2021/11

    DOI： 10.1002/admi.202100979 　

    ISSN： 2196-7350

    eISSN： 2196-7350

  31. Improving self-healing ability and flexural strength of ytterbium silicate-based nanocomposites with silicon carbide nanoparticulates and whiskers Peer-reviewed

    Son Thanh Nguyen, Tsuyoshi Takahashi, Ayahisa Okawa, Hisayuki Suematsu, Koichi Niihara, Tadachika Nakayama

    Journal of the Ceramic Society of Japan　129　(4)　209-216　2021/04

    DOI： 10.2109/jcersj2.20179 　

    ISSN： 1882-0743

    eISSN： 1348-6535

  32. Recycling of a Healing Agent by a Water-Vapor Treatment to Enhance the Self-Repair Ability of Ytterbium Silicate-Based Nanocomposite in Multiple Crack-Healing Test Peer-reviewed

    Son Thanh Nguyen, Tadachika Nakayama, Tsuyoshi Takahashi, Hisayuki Suematsu, Dung Thi Mai Do, Ayahisa Okawa, Koichi Niihara

    Advanced Engineering Materials　22　(7)　2020/07

    DOI： 10.1002/adem.202000157 　

    ISSN： 1438-1656

    eISSN： 1527-2648

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Misc. 3

  1. 基材フリーで高い光沢効果を有する新規パール顔料の開発

    殷 澍, 程 秋, 薛 羿 貝, 大川 采久, 長谷川 拓哉

    塗装技術　64　(6)　47-55　2025/06

  2. Novel Selectivity: Target of Gas Sensing Defined by Behavior (Adv. Mater. 7/2025)

    Lei Miao, Peng Song, Yibei Xue, Zhufeng Hou, Takuya Hasegawa, Ayahisa Okawa, Tomoyo Goto, Yeongjun Seo, Ryo Maezono, Tohru Sekino, Shu Yin

    Advanced Materials　37　(7)　2025/02/19

    Publisher: Wiley

    DOI： 10.1002/adma.202570056 　

    ISSN： 0935-9648

    eISSN： 1521-4095

  3. Titanium Nitride and Yttrium Titanate Nanocomposites, Endowed with Renewable Self‐Healing Ability (Adv. Mater. Interfaces 22/2021)

    Son Thanh Nguyen, Ayahisa Okawa, Hirokazu Iwasawa, Tadachika Nakayama, Hideki Hashimoto, Tohru Sekino, Hisayuki Suematsu, Koichi Niihara

    Advanced Materials Interfaces　8　(22)　2021/11/23

    Publisher: Wiley

    DOI： 10.1002/admi.202170126 　

    ISSN： 2196-7350

    eISSN： 2196-7350

Books and Other Publications 1

  1. Development Trends of Smart Windows

    2023/08

    ISBN: 9784781317465

Presentations 26

  1. Design of Self-Healing Ceramics through Controlled Thermal Processing

    Ayahisa Okawa, Nguyen Thanh Son, Tadachika Nakayama, Hisayuku Suematsu, Takuya, Hasegawa, Shu Yin

    International Conference on Power Engineering for Research Scholars (ICPERS)　2025/05/24

  2. Development of a thermal spraying process using the containerless method Invited

    Ayahisa Okawa

    2025/03/05

  3. Crack healing approach for environmental barrier coatings by heat treatment Invited

    Ayahisa Okawa, Son Nguyen, Tadachika Nakayama, Takehiko Ishikawa, Rina Shimonishi, Chihiro Koyama, Hisayuki Suematsu, Takuya Hasegawa, Shu Yin

    49th International Conference and Expo on Advanced Ceramics and Composites (ICACC2025)　2025/01/29

  4. Advanced Self-Healing Approaches for Engineering Ceramics Invited

    Ayahisa Okawa, Nguyen Thanh Son, Hisayuku Suematsu, Takuya Hasegawa, Yibei Xue, Shu Yin, Tohru Sekino, Tadachika Nakayam

    The 23rd International Symposium on Eco-materials Processing and Design (ISEPD2025)　2025/01/15

  5. Development of Heat Treatment-Induced Self-Healing Ability in Ceramic Coatings Invited

    Ayahisa Okawa, Nguyen Thanh Son, Tadachika Nakayama, Hisayuku Suematsu, Takehiko Ishikawa, Rina Shimonishi, Chihiro Koyama, Takuya Hasegawa, Shu Yin

    2024/12/09

  6. Crack Healing for Robust Environmental Barrier Coating Invited

    Ayahisa Okawa, Son Nguyen, Hisayuki Suematsu, Takuya Hasegawa, Shu yin, Tadachika Nakayama

    The 5th International Conference on Materials Science and Engineering, Materials Oceania 2024　2024/09/24

  7. RE2O3-SiO2 ガラスへの熱処理による⻲裂修復の観察

    大川采久, 長谷川拓哉, 殷澍, 石川毅彦, 下西里奈, 小山千尋, 織田裕久, グエンタンソン, 中山忠親, 増野敦信

    日本マイクログラビティ応用学会 第36回学術講演会 (JASMAC-36)　2024/09/12

  8. 希土類珪酸塩ガラスへの熱処理による微細構造進化の観察

    大川采久, 長谷川拓哉, 殷澍, 石川毅彦, 下西里奈, 小山千尋, 織田裕久, グエンタンソン, 中山忠親

    日本希土類学会 第40回希土類討論会　2024/05/17

  9. 耐環境コーティングへの熱処理による亀裂治癒

    大川 采久, 長谷川拓哉, 殷 澍

    第19回日本セラミックス協会マテリアル・ファブリケーション・デザイン研究会　2024/03/29

  10. Yb2Si2O7およびHo2Si2O7の高温火山灰腐食挙動の観察

    大川 采久, 長谷川 拓哉, 殷 澍, Nguyen Thanh Son, 中山 忠親, 末松 久幸, Do Thi Mai Dung, 後藤 孝

    日本セラミックス協会 2024年年会　2024/03/15

  11. Mechanical properties and self-healing mechanism of SiC dispersed Yb2Si2O7 composite Invited

    Ayahisa Okawa, Son Nguyen, Tadachika Nakayama, Thi Mai Dung Do, Hisayuki Suematsu, Takashi Goto, Koichi Niihara

    48th International Conference and Expo on Advanced Ceramics and Composites (ICACC2024)　2024/01/30

  12. Control of Surface Functional Groups and Room Temperature Gas Sensing Behavior of Nb2CTx

    Ayahisa Okawa, Daisuke Sakamoto, Takuya Hasegawa, Tadaharu Ueda, Shu Yin

    The 37th International Korea-Japan Seminar on Ceramics (KJ-Ceramics 37)　2023/11/16

  13. Control of gas sensing behavior based on various etching methods of MXene

    Ayahisa Okawa, Daisuke Sakamoto, Takuya Hasegawa, Tadaharu Ueda, Shu Yin

    The 3rd USTB-TU Symposium　2023/11/14

  14. Fabrication of rare earth silicate glasses and observation of phase transition behavior

    Ayahisa OKAWA, Nguyen Thanh SON, Takuya HASEGAWA, Tadachika NAKAYAMA, Chihiro KOYAMA, Hirohisa ODA, Rina Shimonishi, Takehiko ISHIKAWA, Do Thi Mai Dung, Shu YIN

    The Japan Society of Microgravity Application, The 35th Conference　2023/10/27

  15. One-step synthesis of MXene exhibiting gas response by hydrothermal-assisted in-situ HF etching

    Ayahisa Okawa, Daisuke Sakamoto, Takuya Hasegawa, Tadaharu Ueda, Shu Yin

    The 36th Autumn Symposium of the Ceramic Society of Japan　2023/09/07

  16. Development of self-healing ceramics and what I learned during my Ph.D study Invited

    Ayahisa Okawa

    The 17th MFD Workshop of the Ceramic Society of Japan　2023/03/29

  17. Synthesis of Nb2CTx by hydrothermal-assisted etching and gas sensor performance in air at room temperature

    Ayahisa Okawa, Mingyang Yang, Takuya Hasegawa, Tadaharu Ueda, Shu Yin

    Annual Meeting 2023 of the Ceramic Society of Japan　2023/03/09

  18. Development of Environmental Barrier Coatings with Repeated Self-healing

    Ayahisa Okawa, Tadachika Nakayama

    Graduate Education Reform Forum 2021　2022/01

  19. The effect of SiC addition to ytterbium disilicate on mechanical properties and self-healing

    Ayahisa Okawa, Son Thanh Nguyen, Hyoungwon Son, Tadachika Nakayama, Thi Mai Dung Do, Hisayuki Suematsu, Koichi Niihara

    46th International Conference and Expo on Advanced Ceramics and Composites (ICACC2022)　2022/01

  20. Preparation of Al2O3-coated silicon carbide particles utilizing aluminum hydroxide

    Ayahisa OKAWA, Son Thanh NGUYEN, Hyoungwon SON, Tadachika NAKAYAMA, Thi Mai Dung Do, Koichi NIIHARA

    The 6th International Conference on "Science of Technology Innovation" 2021 (6th STI-Gigaku 2021)　2021/10

  21. STRENGTH RECOVERY OF SILICON CARBIDE DISPERSED Yb2Si2O7 AT HIGH TEMPERATURE IN AIR OR STEAM ATMOSPHERE

    Ayahisa Okawa, Son Thanh Nguyen, Hyoungwon Son, Tadachika Nakayama, Thi Mai Dung Do, Hisayuki Suematsu, Koichi Niihara

    Symposium on Hybrid Materials and Processing (HyMaP2021)　2021/08

  22. Improvement of Steam Corrosion Resistance by Adding SiC to Yb2Si2O7 Ceramics

    Ayahis Okawa, Kota Arai, Yuma Nakazawa, Tadachika Nakayama

    The 33rd Autumn Symposium of the Ceramic Society of Japan　2020/09

  23. Role of TiC in the two-steps self-healing mechanism of Y2Ti2O7-Y2TiO5-TiC system

    A.Okawa, ST. Nguyen, W. J. Paulo, H. Iwasawa, T. Nakayama, T. Do, H. Suematsu, T. Suzuki, T. Goto, K. Niihara

    44th International Conference and Expo on Advanced Ceramics and Composites (ICACC2020)　2020/01

  24. A two-steps self-healing process and mechanical properties of Y2Ti2O7-Y2TiO5 system

    OKAWA Ayahisa, NGUYEN Thanh Son, WIFF Juan Paulo, IWASAWA Hirokazu, NAKAYAMA Tadachika, DUNG Do Thi Mai, SUEMATSU Hisayuki, SUZUKI Tsuneo, GOTO Takashi, NIIHARA, Koichi

    The 13th Pacific Rim Conference of Ceramic Societies(PACRIM13)　2019/10

  25. Mechanical properties and self-healing ability in Y2Ti2O7-Y2TiO5/TiC composites

    A. Okawa, S. T. Nguyen, J.P. Wiff, H. Iwasawa, T. Nakayama, Do, D.T.M, H. Suematsu, T. Suzuki, T. Goto, K. Niihara

    10th U3 Materials Design Forum Program　2019/03

  26. Effect of TiC addition on Y2Ti2O7-Y2TiO5 ceramics on their mechanical properties and promotion of a self-healing process Invited

    A. Okawa, S. T. Nguyen, W. J. Paulo, H. Iwasawa, T. Nakayama, K. Sugiya, H. Suematsu, T. Suzuki, K. Niihara

    43rd International Conference and Expo on Advanced Ceramics and Composites (ICACC2019)　2019/01

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Industrial Property Rights 5

  1. パール顔料、組成物及びパール顔料の製造方法

    殷 シュウ, テイ シュウウ, 薛 ゲイカイ, 大川 采久, 長谷川 拓哉

    Property Type: Patent

  2. ガス種検知方法、及びそれに基づく疾患検知方法

    大川 采久, YIN SHU, 長谷川, 拓哉, 坂本 大輔

    Property Type: Patent

  3. 半導体式ガスセンサー、おむつ、ガス検知方法、尿及び／又は便の検知方法、おむつ交換時期の決定方法、並びにガス応答性材料

    殷 シュウ, 苗 ライ, 薛 ゲイカイ, 大川 采久, 長谷川 拓哉

    Property Type: Patent

  4. パール顔料、組成物及びパール顔料の製造方法

    殷 シユウ, テイ シュウウ, セツ ゲイカイ, 長谷川 拓哉, 大川 采久

    Property Type: Patent

  5. ガス種検知方法、及びそれに基づく疾患検知方法

    大川采久, 殷シユウ, 長谷川拓哉, 坂本大輔

    Property Type: Patent

Research Projects 5

  1. Development of a highly efficient method of utilising dielectrics with smart pulse power supplies

    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: Nagaoka University of Technology

    2023/04/01 - 2026/03/31

  2. 非晶質希土類珪酸塩の相転移挙動と新亀裂修復メカニズム

    大川 采久

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究

    Institution: 東北大学

    2024/04 - 2026/03

  3. Creation and construction of basic technologies of indium-free functional nanomaterials for smart windows

    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: Tohoku University

    2020/04/01 - 2025/03/31

  4. Development of Crack Healing Mechanism Pioneered by Metastable Phase Sintered Materials

    Offer Organization: Grants-in-Aid for Scientific Research

    System: Research Activity Start-up

    2023/08 - 2025/03

  5. Thermal property measurements and phase transition behavior of rare earth silicates for optimization of thermal spraying and heat treatment of environmental barrier coatings

    Offer Organization: Japan Aerospace Exploration Agency

    2023/04 -

Media Coverage 6

  1. 耐環境コーティングの溶射に向けたハイエントロピー希土類珪酸塩融体の熱物性測定 Myself

    国立研究開発法人宇宙航空研究開発機構 有人宇宙技術部門 宇宙環境利用推進センター きぼう利用プロモーション室　https://humans-in-space.jaxa.jp/kibouser/subject/science/74215.html

    2025/05

    Type: Internet

  2. Low-cost luster: Vanadium phosphate demonstrates potential as substrate-free pearlescent pigment

    The American Ceramic Society　Ceramic Tech Today　https://ceramics.org/ceramic-tech-today/low-cost-luster-vanadium-phosphate-demonstrates-potential-as-substrate-free-pearlescent-pigment/

    2025/02/27

    Type: Internet

  3. 東北大・北陸先端科学技術大学院大・阪大、センシング材料のガス応答パターンを逆転させることに成功

    日本経済新聞　https://www.nikkei.com/article/DGXZRSP685273_W5A110C2000000/

    2025/01/16

    Type: Internet

  4. 東北大、アンモニアを識別するガスセンサー開発

    日刊工業新聞社　https://www.nikkan.co.jp/articles/view/00735645

    2025/01/01

    Type: Internet

  5. Tohoku University and Osaka University have developed a new manufacturing method for pearl pigments that does not require a base material and leads to lower costs.

    Nikkei Inc.

    2024/12/12

    Type: Internet

  6. 大西卓哉宇宙飛行士、宇宙実験を学ぶ 4 東北大学 大川采久助教

    宇宙航空研究開発機構（JAXA） 有人宇宙技術部門　https://humans-in-space.jaxa.jp/space-job/astronaut-report/detail/004229.html

    2024/11/18

    Type: Internet

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