Updated on 2024/07/28

写真a

 
YAMAMOTO NAOJI
 
Organization
Faculty of Engineering Sciences Department of Advanced Energy Science and Engineering Professor
School of Engineering (Concurrent)
Interdisciplinary Graduate School of Engineering Sciences Department of Interdisciplinary Engineering Sciences(Concurrent)
Title
Professor
Profile
I have been studying advanced space propulsions, especially, electric propulsion, for using as a deep space probe. I have been investigating the mechanism of plasma production and loss in order to improve the thrust performance of these propulsion.
External link

Degree

  • Doctor of engineering

Research History

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    なし

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Research Interests・Research Keywords

  • Research theme: ホールスラスタの長寿命化に関する研究

    Keyword: 電気推進、イオン源、不安定性、プラズマ

    Research period: 2007.4

  • Research theme: Improvement of an ion engine performance

    Keyword: Electric propulsion, plasma, measurement

    Research period: 2005.4

  • Research theme: 高周波プラズマの特性測定

    Keyword: 水、プラズマ、RF、ICP

    Research period: 2004.9

  • Research theme: Physics in Hall thrusters

    Keyword: Hall thruster

    Research period: 2004.4

  • Research theme: Development of a miniature microwave discharge ion thruster

    Keyword: Space propulsion, electric propulsion, Ion beam source, ion thruster

    Research period: 2004.4

Awards

  • 第11回プラズマ応用科学会 論文賞

    2013.3   プラズマ応用科学会   論文「イオン加速グリッド損耗解析におけるメッシュサイズおよび時間幅の検討」

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    「イオン加速グリッド損耗解析におけるメッシュサイズおよび時間幅の検討」 として以下のことを明らかにした。
    The JIEDI code (JAXA Ion Engine Development Initiative) is a numerical analysis code for the life evaluation of an ion thruster in order to reduce the life time evaluation cost. For the improvement of this code, appropriate time step and mesh size were investigated. Calculations were conducted on a miniature ion thruster that has been developed in Kyushu University. The calculation cost and the number of sputtered atoms were measured for various numbers of division; various mesh size in the radial direction. The calculation cost, the number of sputtered atoms, the minimum potential and life time were measured for several time steps. When the number of divisions is larger than 24, the number of sputtered atoms converge to 2.2×1011atoms/sec, and the calculation cost is proportional to the cube of the number of divisions. The calculation cost is reduced when the time step is increased, however, if the time step is larger than the critical value, 15% in this study, the life time was overestimated. Considering tradeoff between the accuracy and calculation cost, the appropriate number of divisions in the radial direction is about 24 and the rate of removal of mesh is about 5.0[%].
    この結果として、本論文が第11回プラズマ応用科学会 論文賞を受賞した。

  • 平成23年度若手科学者賞

    2011.4   文部科学省   The demand for mN class miniature propulsion systems for small satellites is expected to grow in the future, due to their relatively low cost and short development time, among other reasons . Until recently, size restrictions have limited the capacity of the available propulsion systems, and this has restricted the capability of small satellites. One of the candidates for mN class miniature propulsion systems is a miniature ion thruster, since an ion thruster produces high thrust efficiency (over 50%) with a specific impulse of 3,000-8,000 sec . He developed a miniature microwave discharge ion thruster. This performance is competitive with that of the thruster developed by Wirz et al., which has hither to shown the best performance in this class of miniature thruster. This will contribute to expand the range and capabilities of small satellites; missions such as Mars exploration would become possible, as would satellite self-disposal. Miniature ion thrusters can also be used for precise high-stability attitude and position control in large spacecraft, as well as for primary propulsion of microsatellites.

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    宇宙利用の敷居を下げる革新技術として注目を集める超小型衛星ではあるが、そのサイズの制約ゆえに推進機は搭載できておらず、現状では大型衛星を脅かす存在とはなっていない。この現状を打破し超小型衛星の性能を飛躍的に向上させるためには、小型・高性能の次世代推進機が必要不可欠である。
    氏は、次世代推進機の有力な候補である小型イオンエンジンの研究・開発に取り組み、その成果として推力0.7 mN、電力から推進力への変換効率57%と、NASAが開発中のエンジンと比肩する世界最高性能のエンジンの開発に成功した。
    本研究成果は、超小型衛星の性能を飛躍的に向上させ、これまで不可能であった小型衛星による月探査や自己廃棄が可能になるなど、萌芽段階にある小型衛星を利用した宇宙開発に爆発的な前進をもたらすと期待される

  • 第19回(平成21年度)航空宇宙学会奨励賞

    2010.4   日本航空宇宙学会   Dependence of Thruster Configuration on Thrust Performance in Miniature Ion Thruster

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    小型イオンスライスタの推進性能における形状依存性


    The effects of antenna shape and magnetic field configuration on thrust performance in a 30 W class miniature microwave discharge ion thruster were investigated with the objective of improving its thrust performance. The ion beam currents were measured for three different antenna configurations: disc, star, and cross. The results showed that the optimum antenna shape depends on the desired mass flow level because of the tradeoff between microwave-plasma coupling efficiency and surface area recombination. The ion beam current with various magnitude of magnetic field was measured, since magnetic confinement and microwave-plasma coupling could be affected by the magnetic field configuration. The ion beam current was increased with increasing the number of magnets, though under too much magnitude of magnetic field, the engine cannot be ignited. So, there is an optimum magnitude of magnetic field. The thrust performance of the miniature microwave discharge ion thruster, i.e., propellant utilization, and ion beam production cost were 0.67 and 660 W/A, respectively, at mass flow rate of 0.018 mg/s, and incident microwave power of 8 W.

  • 2009 Best poster award, 2009 Society of Vacuum Coaters Tech-Conference

    2009.4   2009 Society of Vacuum Coaters TechCon   Laser-Based Sensor for Real Time Sputter Monitoring and End Point Detection in Ion Beam Etch Systems

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    CRDS法を用いて、多層レイヤーの各層の終わりを定量的に知る方法を新たに考案して、実証した

  • 平成23年度科学技術分野の文部科学大臣表彰・若手科学者賞

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Papers

  • Portable Thomson scattering system for temporally resolved plasma measurements under low density conditions Reviewed International journal

    @Yamamoto N., Yalin A.P.

    Review of Scientific Instruments   95 ( 31 )   2024.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI 10.1063/5.0180534

  • Sequential Prediction of Hall Thruster Performance Using Echo State Network Models Reviewed International journal

    #Kansei ITO, @Naoji YAMAMOTO, @Kai MORINO

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES   Volume 67 ( Issue 1 )   1 - 11   2024.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI:doi:10.2322/tjsass.67.1

  • Observation of Plasma Turbulence in a Hall Thruster Using Microwave Interferometry Reviewed International journal

    @Naoji Yamamoto and #Naoya Kuwabara, Daisuke Kuwahara, Shinatora Cho, @Yusuke Kosuga, Guilhem Dif Pradalier

    Journal of Propulsion and Power   39 ( 6 )   849 - 855   2023.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.2514/1.B38711

  • Electron Density Measurement Inside a Hall Thruster Using Microwave Interferometry Reviewed International journal

    #Naoya Kuwabara, #Masatoshi Chono , @Naoji Yamamoto, Daisuke Kuwahara

    Journal of Propulsion and Power   2021.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    Electron number density measurement inside the Hall thruster was demonstrated using a 76 GHz microwave interferometry technique. The electron number density, which depends on the magnetic field strength, was found to be approximately 1018 m-3. Electron density fluctuations were observed at a frequency of 15 kHz, synchronized with the discharge current oscillation. Broadband electron number density fluctuations were also observed in the range of 50-300 kHz, and at approximately 1.5 MHz (width of 200 kHz). This technique shows considerable promise, with the ability to reveal the quantitative relationship between electron number density fluctuations and electron transport, and it will contribute to the understanding of the physics behind anomalous electron transport in Hall thrusters.

    DOI: 10.2514/1.B38163

    Repository Public URL: http://hdl.handle.net/2324/4371074

  • Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique Reviewed International journal

    Naoji Yamamoto, KENTARO TOMITA, Kensaku Sugita, Tomoaki Kurita, Hideki Nakashima, Kiichiro Uchino

    REVIEW OF SCIENTIFIC INSTRUMENTS   83 ( 7 )   2012.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4737144

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Books

  • レクチャー電磁気学

    @山本直嗣(Role:Sole author)

    サイエンス社  2023.9 

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    Language:Japanese   Book type:General book, introductory book for general audience

  • 水素-将来のエネルギーを目指して-, 第9章宇宙ロケットに関わる水素,

    西川正史, 深田智, 渡辺幸信共編.(Role:Joint author)

    東京 : 養賢堂  2006.4 

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    Language:Japanese   Book type:Scholarly book

Presentations

  • Energy Balance in a Radio Frequency Electrothermal Thruster with Water Propellant. International conference

    M. Oya, N. Yamamoto, S. Ogawa, Y. Kajimura and H. Nakashima

    6th Int. Symp. on Applied Plasma Science  2007.9 

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    Presentation type:Oral presentation (general)  

    Venue:Nikko   Country:Japan  

  • Numerical Analysis for Effect of Magnetic Field Configuration on the Trust Performance in a Miniature Ion Engine International conference

    T.Kanagawa, H.Masui, N.Yamamoto, H.Nakashima

    6th Int. Symp. on Applied Plasma Science  2007.9 

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    Presentation type:Oral presentation (general)  

    Venue:Nikko   Country:Japan  

  • ホールスラスタの放電振動, Invited

    山本 直嗣,

    電気推進小研究会〜ホールスラスタについて〜  2006.3 

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    Presentation type:Oral presentation (invited, special)  

    Venue:東京   Country:Japan  

  • A Suppression method of Discharge Current Oscillations in a Hall Thruster International conference

    Naoji Yamamoto, Kimiya Komurasaki and Yoshihiro Arakawa,

    40th AIAA/ASME/SAE/ASEE Joint Propulsion conference & exhibit, 2004.  2004.7 

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    Presentation type:Oral presentation (general)  

    Venue:フロリダ州フォートローダディール   Country:United States  

  • 電気推進ロケットの現状と課題, Invited

    山本 直嗣

    プラズマ夏の学校2004年  2004.8 

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    Presentation type:Oral presentation (invited, special)  

    Venue:盛岡   Country:Japan  

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MISC

  • イオンエンジンのPWM制御時におけるOFF時のリーク電流低減に関する研究

    木下 順平, 白木 僚, 山本 直嗣, 大川 恭志, 船木 一幸, 中野 正勝

    プラズマ応用科学 = Applied plasma science : journal of IAPS   2021.6

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    Language:Japanese  

    Reduction of Leak Current during OFF Period in PWM Control of Ion Engine

  • イオンエンジンにおける FEC を用いた中和システムの検討

    木下 順平, 江川 裕貴, 山本 直嗣, 中野 正勝, 大川 恭志, 船木 一幸, KINOSHITA Junpei, EGAWA Yuki, YAMAMOTO Naoji, NAKANO Masakatsu, OHKAWA Yasushi, FUNAKI Ikkoh

    令和元年度宇宙輸送シンポジウム: 講演集録 = Proceedings of Space Transportation Symposium FY2019   2020.1

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    Language:Japanese  

    Investigation of Neutralization System using FEC for Ion Engine
    Space Transportation Symposium FY2019 (January 16-17, 2020. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

  • 電界放出型カソードを用いたイオンエンジンの中和特性

    山本 直嗣, 池田 凌, 竹末 一平, 森田 太智, 中野 正勝, 大川 恭志, 船木 一幸, Yamamoto Naoji, Ikeda Ryo, Takesue Ippei, Morita Taichi, Nakano Masakatsu, Ohkawa Yasushi, Funaki Ikkoh

    平成30年度宇宙科学に関する室内実験シンポジウム 講演集 = Proceedings of 2019 Symposium on Laboratory Experiment for Space Science   2019.2

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    Language:Japanese  

    Emission characteristics of Field Emission Cathode with cBN emitter under ion thruster operations
    2019 Symposium on Laboratory Experiment for Space Science (February 28 - March 1, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

  • レーザー核融合推進にむけた磁気ノズルによるプラズマ制御の数値解析(2017B2‐MORITA)

    森田太智, 長友英夫, 児島富彦, 山本直嗣, 枝本雅史, 砂原淳, 森芳孝, 城崎知至, 齋藤直哉, 板谷佑太朗, 梶村好宏, 藤岡慎介, 中島秀紀

    大阪大学レーザー科学研究所共同利用・共同研究成果報告書(CD-ROM)   2018.3

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    Language:Japanese  

    レーザー核融合推進にむけた磁気ノズルによるプラズマ制御の数値解析(2017B2‐MORITA)

  • 将来ミッションに向けた電気推進ロケットエンジンの現状と課題

    山本直嗣, 渡邊裕樹

    2018.2

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    Language:Japanese  

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Industrial property rights

Patent   Number of applications: 1   Number of registrations: 1
Utility model   Number of applications: 0   Number of registrations: 0
Design   Number of applications: 0   Number of registrations: 0
Trademark   Number of applications: 0   Number of registrations: 0

Professional Memberships

  • 日本航空宇宙学会

  • American Institute of Aeronautics and Astronautics

  • Institute of Applied Plasma Science

  • THe Japan Society of Applied Physics

  • Japan Society of Aeronautical and Space Sciences

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Committee Memberships

  • 日本航空宇宙学会   Steering committee member   Domestic

    2020.4 - 2022.3   

  • 日本航空宇宙学会   西部支部 委員   Domestic

    2020.4 - 2022.3   

  • 日本航空宇宙学会   Steering committee member   Domestic

    2018.3 - 2021.3   

  • 日本航空宇宙学会   日本航空宇宙学会 電気推進・先端推進部門 委員   Domestic

    2018.3 - 2021.3   

  • 運営委員   Steering committee member   Domestic

    2012.4 - 2013.3   

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Academic Activities

  • Screening of academic papers

    Role(s): Peer review

    2019

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    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:6

    Number of peer-reviewed articles in Japanese journals:2

    Proceedings of International Conference Number of peer-reviewed papers:2

  • Screening of academic papers

    Role(s): Peer review

    2018

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    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:6

    Number of peer-reviewed articles in Japanese journals:4

  • Screening of academic papers

    Role(s): Peer review

    2017

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    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:5

    Number of peer-reviewed articles in Japanese journals:2

  • 出版委員会 International contribution

    34rd International Electric Propulsion Conference  ( kobe Japan ) 2016.7

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    Type:Competition, symposium, etc. 

    Number of participants:400

  • 出版委員会 International contribution

    the 30th International Symposium on Space Technology and Science  ( kobe Japan ) 2016.7

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    Type:Competition, symposium, etc. 

    Number of participants:1,000

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Research Projects

  • ホールスラスタにおけるプラズマ乱流の理解と制御

    Grant number:22H00243  2022 - 2024

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • 電気推進機における昇華性推進剤の検討

    2021.6 - 2022.2

    Joint research

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    Authorship:Coinvestigator(s)  Grant type:Other funds from industry-academia collaboration

  • レーザー核融合ロケットに関する研究

    2021.4 - 2022.3

    Joint research

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    Authorship:Coinvestigator(s)  Grant type:Other funds from industry-academia collaboration

  • 電気推進機プラズマの観測技術の研究

    2021.2 - 2021.6

    Joint research

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    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • レーザー核融合ロケットにおけるデタッチメント現象の解明

    Grant number:21K18176  2021 - 2024

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Challenging Research(Pioneering)

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    Authorship:Principal investigator  Grant type:Scientific research funding

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Educational Activities

  • 「Advanced Space Propulsion Engineering」
    「Energy Conversion Measurement Engineering」

Class subject

  • 航空力学

    2023.12 - 2024.2   Winter quarter

  • 電磁気学E

    2023.10 - 2024.3   Second semester

  • 電磁気学Ⅰ

    2023.10 - 2024.3   Second semester

  • 材料力学Ⅱ(S2-21)

    2023.6 - 2023.8   Summer quarter

  • 基礎材料力学Ⅰ

    2023.4 - 2024.3   Full year

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FD Participation

  • 2020.12   Role:Participation   Title:高圧ガス及び液化ガスを安全に取り扱うための講習会

    Organizer:University-wide

  • 2020.9   Role:Participation   Title:科研費セミナー(学内:研究者対象)」

    Organizer:University-wide

  • 2018.11   Role:Planning   Title:総理工セミナー

    Organizer:[Undergraduate school/graduate school/graduate faculty]

  • 2018.6   Role:Participation   Title:アイソトープ統合センター研修

    Organizer:University-wide

  • 2017.8   Role:Participation   Title:平成30年度科学研究費助成事業獲得セミナー(学内:研究者対象)」

    Organizer:University-wide

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Other educational activity and Special note

  • 2018  Class Teacher  学部

  • 2017  Class Teacher  学部

  • 2016  Class Teacher  学部

  • 2015  Class Teacher  学部

Outline of Social Contribution and International Cooperation activities

  • コロラド州立大学およびフランス原子力および代替エネルギー庁とホールスラスタの研究に関して共同研究を推進している

Social Activities

  • 工学部出前講義

    倉敷青陵高校  2023.12

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    Audience:Infants, Schoolchildren, Junior students, High school students

    Type:Seminar, workshop

  • 福岡高校との高大連携プログラム

    福岡高校  九州大学筑紫キャンパス  2019.7

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    Audience:General, Scientific, Company, Civic organization, Governmental agency

    Type:Other

    20人規模の高校生を受け入れ、大学で研究するとは、どのような事なのか実際に触れてもらう企画であり、さらにOB、OGとの懇談を通して、大学とはどういうところかという雰囲気を味わうことにより、モチベーションの向上並びに大学へのスムーズな接続を計る。

  • 「工学-アイデアを実現していく学問プラズマロケット開発を通して-」

    春吉中学  2018.9

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    Audience:Infants, Schoolchildren, Junior students, High school students

    Type:Seminar, workshop

  • 宇宙にも拡がる電化の流れ

    福岡県立育徳館高等学校出前講義  2018.7

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    Audience:Infants, Schoolchildren, Junior students, High school students

    Type:Seminar, workshop

  • SSH受け入れ

    城南高校  2018.6

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    Audience:Infants, Schoolchildren, Junior students, High school students

    Type:Other

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Activities contributing to policy formation, academic promotion, etc.

  • 2018.10   レーザー学会

    レーザー夏の学校 講師

Educational Activities for Highly-Specialized Professionals in Other Countries

  • 2018.10   台湾成功大学との研究交流

    Main countries of student/trainee affiliation:Taiwan, Province of China

    Other countries of student/trainee affiliation:台湾

  • 2018.5 - 2018.7   インターンシップ

    Main countries of student/trainee affiliation:India

Travel Abroad

  • 2022.8 - 2023.3

    Staying countory name 1:United States   Staying institution name 1:コロラド州立大学

  • 2020.2 - 2020.7

    Staying countory name 1:France   Staying institution name 1:フランス原子力および代替エネルギー庁

  • 2018.11

    Staying countory name 1:Taiwan, Province of China   Staying institution name 1:台湾成功大学

  • 2017.3 - 2017.4

    Staying countory name 1:Taiwan, Province of China   Staying institution name 1:台湾成功大学

  • 2016.4

    Staying countory name 1:China   Staying institution name 1:上海交通大学

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