2026/07/19 更新

写真a

ナガヒロ　リョウヘイ
永廣　怜平
Ryohei Nagahiro
所属
大学院工学研究科 機械システム分野 機械材料物性研究室 助教   
学位
博士（工学） （ 2025年3月   東京大学 ）
ホームページ
https://mme-lab.github.io/
外部リンク

研究分野

  • ものづくり技術（機械・電気電子・化学工学） / 熱工学

  • ナノテク・材料 / ナノ構造物理

主な研究論文

経歴

  • 豊田工業大学   大学院工学研究科 機械システム分野 機械材料物性研究室   助教

    2026年7月 - 現在

  • 東京大学   大学院工学系研究科 附属総合研究機構   特任研究員

    2025年8月 - 2026年7月

    　 詳細

    国名：日本国

  • 東京大学   大学院工学系研究科 機械   技術補佐員

    2025年5月 - 2025年7月

    　 詳細

    国名：日本国

  • 日本学術振興会   特別研究員

    2021年4月 - 2023年3月

    　 詳細

    国名：日本国

▼全件表示

学歴

  • 東京大学   工学系研究科   機械工学専攻

    2020年4月 - 2025年3月

    　 詳細

    国名： 日本国

    備考： 博士（工学）

  • 群馬大学   理工学府   理工学専攻

    2018年4月 - 2020年3月

    　 詳細

    国名： 日本国

    備考： 修士

  • 群馬大学   理工学部   機械知能システム理工学科

    2014年4月 - 2018年3月

    　 詳細

    国名： 日本国

    備考： 学士

所属学協会

  • 日本熱電学会

  • 日本伝熱学会

  • 応用物理学会

論文

  • Control of thermal conductivity in amorphous silicon oxide and silicon oxynitride thin films via ubiquitous transition metal doping 査読

    Michiko Sasaki, Kunihiko Shizume, Ryohei Nagahiro, Junichiro Shiomi, Masahiro Goto

    Japanese Journal of Applied Physics   65 ( 11 )   115502 - 115502   2026年6月 （   ISSN:0021-4922   eISSN:1347-4065 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

    Abstract

    We report a strategy to tune and reduce thermal conductivity (TC) in dense amorphous silicon oxide (SiO x ) and silicon oxynitride (SiN x O y ) thin films through ubiquitous transition metal doping (iron [Fe], nickel [Ni], and chromium [Cr]) combined with process parameter control. Using a custom combinatorial sputter coating system, we fabricated multipoint libraries on single Si substrates and measured TC using frequency-domain thermoreflectance. Fe-, Ni-, and Cr-doped amorphous SiO x achieved an ultralow TC of 0.51 W m −1 K −1 , below typical glass-limit values reported for dense amorphous SiO 2 /SiN x . Anomalously high-TC samples (up to 2.2 W m −1 K −1 ) were linked to nanocrystalline phase formation. Principal component analysis revealed that in SiO x , TC is governed primarily by sputtering power, pressure, and target–substrate distance rather than dopant level, indicating structure-mediated suppression of long-mean free path propagon-like modes. In SiO x N y , TC spans 0.68–2.5 W m −1 K −1 ; and a distinct mechanism involving heavy element incorporation and a more open amorphous network. This approach enables continuous TC tailoring (0.51–2.5 W m −1 K −1 ) for robust high-temperature insulation coatings.

    DOI： 10.35848/1347-4065/ae6e81

    その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ae6e81/pdf

  • The Frequency Domain Thermoreflectance Technique for Thermal Property Measurements 査読

    Alesanmi R. Odufisan, Benjamin Stern, Ryohei Nagahiro, Rosemary Wynnychenko, Sevan Chanakian, Junichiro Shiomi, Eleonora Isotta, Oluwaseyi Balogun

    Journal of Visualized Experiments   ( 226 )   2025年12月 （     eISSN:1940-087X ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：MyJove Corporation  

    DOI： 10.3791/68908

  • A thermal boundary resistance model via mean free path suppression functions and a Gibbs excess approach 査読

    Eleonora Isotta, Ryohei Nagahiro, Alesanmi R. Odufisan, Junichiro Shiomi, Oluwaseyi Balogun, G. Jeffrey Snyder

    International Journal of Heat and Mass Transfer   252   127417 - 127417   2025年12月 （   ISSN:0017-9310 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

    DOI： 10.1016/j.ijheatmasstransfer.2025.127417

  • Module-scale silicon 3D softened nanoarchitectures for eco-friendly thermoelectric energy harvesting 査読

    Ryohei Nagahiro, Bin Xu, Shingo Terashima, Yifei Li, Yuanzhe Li, Yuxuan Liao, Zhenglong Fang, Cheng Shao, Masato Ohnishi, Shinya Kato, Eiji Iwase, Junichiro Shiomi

    Materials Today Physics   57   101798 - 101798   2025年9月 （   ISSN:2542-5293 ）

    　詳細

    担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

    DOI： 10.1016/j.mtphys.2025.101798

  • Heat Transport at Silicon Grain Boundaries 査読

    Eleonora Isotta, Shizhou Jiang, Ruben Bueno‐Villoro, Ryohei Nagahiro, Kosuke Maeda, Dominique Alexander Mattlat, Alesanmi R. Odufisan, Alexandra Zevalkink, Junichiro Shiomi, Siyuan Zhang, Christina Scheu, G. Jeffrey Snyder, Oluwaseyi Balogun

    Advanced Functional Materials   34 ( 40 )   2024年7月 （   ISSN:1616-301X   eISSN:1616-3028 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

    Abstract

    Engineering microstructural defects, like grain boundaries, offers superior control over transport properties in energy materials. However, technological advancement requires establishing microstructure‐property relations at the micron or finer scales, where most of these defects operate. Here, the first experimental evidence of thermal resistance for individual silicon grain boundaries, estimated with a Gibbs excess approach, is provided. Coincident site lattice boundaries exhibit uniform excess thermal resistance along the same boundary, but notable variations from one boundary to another. Boundaries associated with low interface energy generally exhibit lower resistances, aligning with theoretical expectations and previous simulations, but several exceptions are observed. Transmission electron microscopy reveals that factors like interface roughness and presence of nanotwinning can significantly alter the observed resistance, which ranges from ∼0 to up to ∼2.3 m2K/GW. In stark contrast, significantly larger and less uniform values ‐ from 5 to 30 m2K/GW ‐ are found for high‐angle boundaries in spark‐plasma‐sintered polycrystalline silicon. Further, finite element analysis suggests that boundary planes that strongly deviate from the sample vertical (beyond ∼45°) can show up to 3‐times larger excess resistance. Direct correlations of properties with individual defects enable the design of materials with superior thermal performance for applications in energy harvesting and heat management.

    DOI： 10.1002/adfm.202405413

  • Extremely suppressed thermal conductivity of large-scale nanocrystalline silicon through inhomogeneous internal strain engineering 査読

    Bin Xu, Yuxuan Liao, Zhenglong Fang, Yifei Li, Rulei Guo, Ryohei Nagahiro, Yoshifumi Ikoma, Masamichi Kohno, Junichiro Shiomi

    Journal of Materials Chemistry A   11 ( 35 )   19017 - 19024   2023年 （   ISSN:2050-7488   eISSN:2050-7496 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Royal Society of Chemistry (RSC)  

    Record low thermal conductivity was achieved in large-scale crystal silicon due to the effect of inhomogeneous internal strain-induced phonon engineering via HPT processing.

    DOI： 10.1039/d3ta03011c

  • Nondestructive observation of pores during press forming of aluminum foam by X-ray radiography 査読

    Yoshihiko Hangai, Daisuke Kawato, Mizuki Ando, Masataka Ohashi, Yoshiaki Morisada, Takuya Ogura, Hidetoshi Fujii, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    Materials Characterization   170   110631 - 110631   2020年12月 （   ISSN:1044-5803 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

    DOI： 10.1016/j.matchar.2020.110631

  • Continuous Foaming of Multiple Aluminum Foam Precursors by Combining Conveyor and Optical Heating 査読

    Yoshihiko Hangai, Masataka Ohashi, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    MATERIALS TRANSACTIONS   61 ( 8 )   1703 - 1706   2020年8月 （   ISSN:1345-9678   eISSN:1347-5320 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Institute of Metals  

    DOI： 10.2320/matertrans.mt-m2020137

  • Foaming of A1050 aluminum precursor by generated frictional heat during friction stir processing of steel plate 査読

    Yoshihiko Hangai, Keisuke Takada, Hidetoshi Fujii, Yasuhiro Aoki, Yuma Aihara, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    The International Journal of Advanced Manufacturing Technology   106 ( 7-8 )   3131 - 3137   2020年1月 （   ISSN:0268-3768   eISSN:1433-3015 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

    DOI： 10.1007/s00170-019-04834-4

    その他リンク： http://link.springer.com/article/10.1007/s00170-019-04834-4/fulltext.html

  • Uniform Heating Model Analysis for the Formation Process of Aluminium Foam by Spot-Type Halogen Lamp 査読

    R. Nagahiro, N. Rosli, Y. Hangai, A. Yano, K. Amagai

    International Journal of Automotive and Mechanical Engineering   16 ( 4 )   7170 - 7180   2019年12月 （   ISSN:2229-8649   eISSN:2180-1606 ）

    　詳細

    担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Universiti Malaysia Pahang Al-Sultan Abdullah Press (UMPSA Press)  

    Heat treatment by heating furnace has limited the capability of heat treatment processes to control the desired heating volume and products’ sizes. This study introduced a heat treatment process using light heat sourced from a spot-type halogen lamp, with the aim of clarifying the thermal phenomenon of aluminium (Al) foam. Here, the temperature and deformation of Al foam were observed experimentally. In addition, thermal analysis was conducted numerically using a uniform heating model by neglecting the energy consumption of the blowing agent and deformation and thermal conductivity of Al. The experimental results revealed that the precursor initially formed at almost the same time as the phase change. The numerical results almost corresponded with the experimental results until the melting point of Al, after which a slight disagreement was observed. Moreover, the phase transformation appeared slightly earlier as a result of neglecting the deformation of Al foam and energy consumption of the blowing agent. Although the formation of Al foam cannot be expressed perfectly using the proposed uniform heating model, a qualitative phenomenon of such formation was successfully explained. In the future, the effects of deformation and energy consumption of the blowing agent and the thermal conductivity of Al can be considered in the proposed uniform heating model.

    DOI： 10.15282/ijame.16.4.2019.02.0536

  • Press Forming of Aluminum Foam during Foaming of Precursor 査読

    Yoshihiko Hangai, Masataka Ohashi, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    MATERIALS TRANSACTIONS   60 ( 11 )   2464 - 2469   2019年11月 （   ISSN:1345-9678   eISSN:1347-5320 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Institute of Metals  

    DOI： 10.2320/matertrans.mt-m2019192

  • Fabrication of aluminum foam with complex shapes using pin screen mold and effect of arrangement of pins on its surface morphology 査読

    Yoshihiko Hangai, Keita Takahashi, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    Journal of Porous Materials   27 ( 2 )   347 - 353   2019年10月 （   ISSN:1380-2224   eISSN:1573-4854 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

    DOI： 10.1007/s10934-019-00810-1

    その他リンク： http://link.springer.com/article/10.1007/s10934-019-00810-1/fulltext.html

  • Shaping of Aluminum Foam during Foaming of Precursor Using Steel Mesh with Various Opening Ratios 査読

    Yoshihiko Hangai, Ryohei Nagahiro, Masataka Ohashi, Kenji Amagai, Takao Utsunomiya, Nobuhiro Yoshikawa

    Metals   9 ( 2 )   223 - 223   2019年2月 （     eISSN:2075-4701 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

    In this study, steel meshes with various opening ratios φ were used to shape aluminum foams during precursor foaming. The effect of φ on the heating rate and shape of the obtained aluminum foams was investigated. It was found that steel meshes with various opening ratios can be used to shape aluminum foam. There is no significant effect on the pore structures of the obtained aluminum foams when upward expansion is restricted during foaming, regardless of the value of φ. The meshes with higher φ clearly transfer the mesh pattern onto the surface of the aluminum foam but require a shorter foaming time. In contrast, the lower-φ meshes produce aluminum foams with a smoother surface but a longer foaming time is required.

    DOI： 10.3390/met9020223

  • Refoaming of deformed aluminum foam by precursor foaming process 査読

    Yoshihiko Hangai, Hayato Matsushita, Ryosuke Suzuki, Shinji Koyama, Kenji Amagai, Ryohei Nagahiro, Takao Utsunomiya, Masaaki Matsubara, Nobuhiro Yoshikawa

    Journal of Porous Materials   26 ( 4 )   1149 - 1155   2019年1月 （   ISSN:1380-2224   eISSN:1573-4854 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

    DOI： 10.1007/s10934-018-0716-y

    その他リンク： http://link.springer.com/article/10.1007/s10934-018-0716-y/fulltext.html

  • Shaping of Aluminum Foam Using Point Group Mold 査読

    Yoshihiko Hangai, Keita Takahashi, Ryohei Nagahiro, Kenji Amagai, Takao Utsunomiya

    MATERIALS TRANSACTIONS   59 ( 12 )   1952 - 1955   2018年12月 （   ISSN:1345-9678   eISSN:1347-5320 ）

    　詳細

    掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Institute of Metals  

    DOI： 10.2320/matertrans.m2018281

▼全件表示

講演・口頭発表等

  • A Thermal Boundary Resistance model via mean free path suppression functions and a Gibbs excess approach 国際会議

    Eleonora Isotta, Rryohei Nagahiro, Alesanmi Richmond, Rerelope Odufisan, Junichiro Shiomi, Oluwaseyi Balogun, G. Jeffrey Snyder

    2025 MRS Spring Meeting & Exhibit  ( Seattle Convention Center, Washington )   2025年4月 

    　詳細

    記述言語：英語   会議種別：ポスター発表  

    SF01.09.02

  • Validation of Gibbs Excess methods with bonded Si wafer 招待 国際会議

    Rryohei Nagahiro, Eleonora Isotta, G. Jeffrey Snyder, Oluwaseyi Balogun, Junichiro Shiomi

    The 1st A3 Nano & Thermal Energy Engineering Workshop  ( Sanjo Conference Hall (The University of Tokyo), Tokyo )   2025年1月 

    　詳細

    記述言語：英語   会議種別：ポスター発表  

    P1-16

  • Direct observation of thermal boundary resistance in silicon system 国際会議

    Ryohei Nagahiro, Kazuhiro Maeda, Eleonora Isotta, Shuo Jiang, G. Jeffrey Snyder, Oluwatobi Balogun, Junichiro Shiomi

    The Third Asian Conference on Thermal Sciences  ( Shanghai Fuyue Hotel, Shanghai )   2024年6月 

    　詳細

    記述言語：英語   会議種別：口頭発表（一般）  

    O-0634

  • Strain Engineering in 3D Architected Silicon for High-Performance Thermoelectric Energy Harvesting 国際会議

    Bin Xu, Ryohei Nagahiro, Shingo Terashima, Cheng Shao, Yifei Li, Zhenglong Fang, Yuanzhe Li, Yuxuan Liao, Masato Ohnishi, Shinya Kato, Eiji Iwase, Junichiro Shiomi

    The Third Asian Conference on Thermal Sciences  ( Shanghai Fuyue Hotel, Shanghai )   2024年6月 

    　詳細

    記述言語：英語   会議種別：口頭発表（一般）  

    O-0034

  • Machine-Learning Minimization of Amorphous Heat Conduction by High-Throughput Deposition Process in The Loop 国際会議

    Kunihiko Shizume, Ryohei Nagahiro, Michoko Sasaki, Masahiro Goto, Junichiro Shiomi

    2024 MRS Spring Meeting & Exhibit  ( Seattle Convention Center, Washington )   2024年4月 

    　詳細

    記述言語：英語   会議種別：口頭発表（一般）  

    MT03.02.08

  • Thermoelectric performance of bulk silicon with 3D nano-architecture 国際会議

    Ryohei Nagahiro, Bin Xu, Shingo Terashima, Cheng Shao, Yifei Li, Zhenglong Fang, Yuanzhe Li, Yuxuan Liao, Masato Ohnishi, Shinya Kato, Eiji Iwase, Junichiro Shiomi

    The 39th Annual International Conference on Thermoelectrics  ( The University of Washington, Seattle )   2023年6月 

    　詳細

    記述言語：英語   会議種別：口頭発表（一般）  

▼全件表示