専門・基盤技術グループ

Yuki SAKAMOTO

  (坂本 勇樹)

Profile Information

Affiliation
Assistant Professor, Institute of Space and Astronautical Science, Department of Space Flight Systems, Japan Aerospace Exploration Agency
Degree
博士(工学)(早稲田大学)

J-GLOBAL ID
201901007239946011
researchmap Member ID
B000355489

Education

 3

Papers

 20
  • Hideki Tatsumoto, Takumi Hasegawa, Yuki Sakamoto, Yuki Shiro, Yuka Horikawa, Hiroaki Kobayashi, Makoto Teshigawara, Hossein Sina
    Cryogenics, 139, Apr, 2024  
    At the European Spallation Source (ESS) ERIC, the liquid hydrogen moderator development is undertaken for its predominantly high parahydrogen fraction, which helps to attain a higher neutron intensity at a very high brightness. The Cryogenic Moderator System (CMS) is equipped with a catalyst to convert hydrogen from the ortho to the parastate to keep desirably high parahydrogen fractions of more than 99.5% in the cold moderators, which is required to deliver high brightness cold neutron beams to the neutron instruments. An in-situ measurement system for the ortho and para fractions of liquid hydrogen (OPMS) has been developed using a Raman spectroscopy to detect any undesirable shift towards a high orthohydrogen fraction caused by neutron scattering driven para-to-ortho back conversion. A Raman optics system was installed into a mock-up OPMS vacuum chamber and its performance evaluation tests have been conducted by flowing liquid hydrogen. It was verified that the developed Raman optics system succeeded in measuring the parahydrogen fraction with an accuracy of 0.1%, which met the requirement.
  • 須田公平, 吹場活佳, 堀伊吹, 川崎央, 小林弘明, 坂本勇樹
    日本冷凍空調学会論文集, 41(2), 2024  
  • 坂本勇樹, 小林弘明, 竹崎悠一郎, 成尾芳博, 谷本圭亮, 川口潤
    日本冷凍空調学会論文集, 41(2), 2024  
  • Yuki Sakamoto, Hiroaki Kobayashi, Yoshihiro Naruo, Yuichiro Takesaki, Tetsuya Sato
    Cryogenics, 131 103652-103652, Apr, 2023  
  • Nakao Keigo, Sakano Yukari, Sakamoto Yuki, Kabayama Koki, Inoue Yusuke, Sato Tetsuya
    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 21 68-76, 2022  
    Cryogenic fluids such as liquid hydrogen and liquid oxygen used as the rocket propellants easily evaporate and form the gas-liquid two-phase flow. The control of the two-phase flow is difficult due to the large fluctuation of the density. For high-precision control, it is necessary simultaneously to understand flow regimes which represent a gas-liquid distribution pattern. Therefore, in this paper, we developed a classifier that uses Bidirectional LSTM networks, which is part of a family of deep learning methods, with a measured value of a void fraction meter as input and gas-liquid flow rate conditions as output, in order to realize a flow regime classifier in the future. The classifier succeeded in classifying with more than 80% accuracy. In addition, in order to verify what features of the input data the classifier captures, a test data-set of which frequency was artificially changed was classified. As a result, it was confirmed that the classifier would use the frequency component of the input data as one of the basis for classification.

Presentations

 79
  • Yuki Sakamoto, Hiroaki Kobayashi, Yusuke Maru, Shinichiro Tokudome, Akira Oyama, Shinsuke Takeuchi, Masashi Miura, Daisaku Masaki, Satoshi Takada, Hiromitsu Kakudo, Toru Kaga, Ryoma Yamashiro, Kiyoshi Kinufuchi, Hiroyasu Manako, Masaharu Uchiumi, Dasuke Naka, Hikaru Eguchi, Ryojiro Minato, Katsuyoshi Fukiba, Akira Kawasaki, Shinichi Maeda, Yoichi Takeda, Tetsuya Sato
    Space Propulsion 2024, May, 2024
  • SAKAMOTO, Yuki, KOBAYASHI, Hiroaki, MARU, Yusuke, TOKUDOME, Shinichiro, OYAMA, Akira, TAKEUCHI, Shinsuke, MIURA, Masashi, MASAKI, Daisaku, TAKADA, Satoshi, KAKUDO, Hiromitsu, KAGA, Toru, YAMASHIRO, Ryoma, KINUFUCHI, Kiyoshi, MANAKO, Hiroyasu, UCHIUMI, Masaharu, NAKATA, Daisuke, EGUCHI, Hikaru, MINATO, Ryojiro, FUKIBA, Katsuyoshi, KAWASAKI, Akira, MAEDA, Shinichi, TAKEDA, Yoichi, SATO, Tetsuya
    Proceedings of Sounding Rocket Symposium 2023, Feb, 2024
    誤記: NAKATA, Dasuke
  • 丸祐介, 佐藤哲也, 小林弘明, 大山聖, 坂本勇樹
    航空原動機・宇宙推進講演会講演論文集(CD-ROM), 2024
  • Hiroaki Kobayashi, Shinichiro Tokudome, Yusuke Maru, Sakamoto Yuki(JAXA), Sato, Tetsuya(Waseda University
    Asian Joint Conference on Propulsion and Power 2023, Mar, 2023
  • Yuki Sakamoto, Hiromitsu Kakudo, Ryoma Yamashiro, Masashi Miura, Akira Oyama, Shujiro Sawai, Shinichiro Tokudome, Yusuke Maru, Hiroaki Kobayashi(JAXA, Tetsuya Sato(Waseda University, Matthew Richardson(The, University of Tokyo, Hikaru Eguchi, Daisuke Nakata(Muroran, Institute of Technology
    Asian Joint Conference on Propulsion and Power 2023, Mar, 2023

Research Projects

 6