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32 results on '"Asai, Fumio"'

5. Study on network utilization of amateur radio band ground stations for nanosatellite

Author

TOKUMITSU, Masahiro, TAKADA, Taku, NAKAYA, Jun, ASAI, Fumio, and IMAI, Kazumasa

Subjects
nanosatellite, CubeSat, ground station network, orbital calculation, satellite communication
Abstract

2021年度に打ち上げ予定のJAXA革新的衛星技術実証2号機に採択されたCubeSat「KOSEN-1」の衛星運用のために，国内にあるアマチュア無線帯用の11地上局をネットワーク利用することを計画している．CubeSatなどの超小型人工衛星の衛星運用を効率よく実施するためには，複数の地上局を活用することが有用と考えられる．高専連携地上局ネットワークの情報をもとに，軌道計算ソフトウェアを利用し，KOSEN-1衛星の運用が可能な回数や通信予想時間の増大分を見積った．複数局の可視時間帯が重なる場合には，異なる偏波受信アンテナに変更することや，同時受信した複数局のデータから欠損データを推定することで，結果として，良質のデータを得られると考えている．また，可視時間の重なる複数のCubeSatデータを受信するためには，受信に特化させた安価で簡易的な受信装置が有効であり，本研究で開発した簡易型受信機の長期間受信実験の結果から，管制局と簡易型受信機の組み合わせにより，データ受信量の増大が期待できることが示唆された．, For the satellite operation of CubeSat ''KOSEN-1'' adopted on JAXA's innovative satellite technology demonstration-2 scheduled to be launched in 2021, we plan to use 11 ground stations for amateur radio band in Japan as a network. It is considered useful to utilize multiple ground stations in order to efficiently carry out satellite operation of nanosatellite such as CubeSat. In this paper, the orbit calculation software was used to calculate the increase in the number of possible satellite operations and the expected communication time, based on the information of the KOSEN-1 cooperation ground stations network. When the visible time zones of multiple stations overlap, it is considered that good quality data can be obtained by changing to different polarized wave receiving antennas and also estimating missing data from the data of multiple stations received simultaneously. In order to receive multiple CubeSat data that are continuously ejected in space, an inexpensive and simple receiver specialized for data receiving is effective. Based on the result of long-term receiving experiment of the simple receiver developed in our team, it is suggested that the combination of the main control ground stations and simple receiver can be expected to increase the amount of data received., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA2030022009, レポート番号: JAXA-RR-20-010

Published
2021

8. 国立高専連携衛星KOSEN-1のための高専地上局ネットワーク活用の試み

Author

TOKUMITSU, Masahiro, TAKADA, Taku, NAKAYA, Jun, ASAI, Fumio, and IMAI, Kazumasa

Abstract

2019(令和元)年度宇宙科学情報解析シンポジウム(2020年2月14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, Space Science Informatics Symposium FY2019(February 14, 2020. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000150009

Published
2020

13. Highly Transparent and Tough Filler Composite Elastomer Inspired by the Cornea

Author

Watanabe, Kenta, primary, Miwa, Eiji, additional, Asai, Fumio, additional, Seki, Takahiro, additional, Urayama, Kenji, additional, Nakatani, Tomotaka, additional, Fujinami, So, additional, Hoshino, Taiki, additional, Takata, Masaki, additional, Liu, Chang, additional, Mayumi, Koichi, additional, Ito, Kohzo, additional, and Takeoka, Yukikazu, additional

Published
2020
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17. Education in Aerospace Engineering: A Report on the 2016 KOSEN Space Camp

Author

WAKABAYASHI, Makoto, primary, TAKADA, Taku, additional, IMAI, Kazumasa, additional, KAJIMURA, Yoshihiro, additional, NAKAYA, Jun, additional, KITAMURA, Kentarou, additional, MURAKAMI, Yukikazu, additional, ASAI, Fumio, additional, TOKUMITSU, Masahiro, additional, SHINOHARA, Manabu, additional, and SHIMADA, Kazuo, additional

Published
2019
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19. Diastereoselective synthesis of N-secondary alkyl 2-alkoxymethylpyrrolidines via sequential addition reactions of organolithium and -magnesium reagents to N-thioformyl 2-alkoxymethylpyrrolidines

Author

Murai, Toshiaki and Asai, Fumio

Subjects
Sequential analysis -- Usage, Organolithium compounds -- Chemical properties, Organolithium compounds -- Structure, Magnesium -- Chemical properties, Magnesium -- Structure, Diastereomers -- Analysis, Biological sciences, Chemistry
Abstract

Highly efficient sequential addition reactions of organolithium and -magnesium reagents to N-thioformyl 2-methoxymethylpyrrolidine are described. The reaction is extended to N-thioformyl 2-siloxymethypyrrolidine and 2-methoxymethylpiperidine, which has showed similar efficiency and selectivity.

Published
2008

20. Three-component coupling reactions of thioformamides with organolithium and Grignard reagents leading to formation of tertiary amines and a thiolating agent

Author

Murai, Toshiaki and Asai, Fumio

Subjects
Lithium compounds -- Chemical properties, Lithium compounds -- Structure, Amines -- Chemical properties, Amines -- Structure, Chemistry
Abstract

A new three-component coupling reaction of thioformamides was studied. Addition of organolithium and Grignard reagents leads to the formation of tertiary amines and the byproduct [LiSMgBr] formed in this reaction serves as a new thiolating agent.

Published
2007

31. A Thermal Model for Kaon Production in Relativistic Heavy-Ion Collisions

Author

Asai, Fumio and Sano, Mitsuo

Abstract

Multiple collision effects on inclusive kaon spectra resulting from relativistic heavy-ion collisions are studied on the basis of a thermal model. The kaon production rates are determined by a realistic probability for producing a kaon in N-N collisions in free space instead of the assumption of chemical equilibrium. The calculated spectra are compared with the prediction based on the linear cascade model by Randrup et al. The spectra at large angles are found to be greatly influenced by multiple collision effects.

Published
1981
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32. Improvement of mechanical properties of elastic materials by chemical methods.

Author

Takeoka Y, Liu S, and Asai F

Abstract

Elastomers such as gels and rubbers play various roles in our lives. Elastomers, which guarantee the safety of airplanes and automobiles and the stability of buildings, are materials that have made the lives of people in the twentieth century extremely convenient. The existence of macromolecules, that is, giant molecules, has been clarified; the development of synthetic macromolecules has progressed; and understanding of elastomers has progressed. By introducing new ideas, it has become possible to obtain tough and hard elastomers, which was difficult under conventional ideas. In this paper, we will explain the development from the classical theory of elastomers to current efforts., Competing Interests: No potential conflict of interest was reported by the authors., (© 2021 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)

Published
2021
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