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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Ti
during hydrogen cyclingKim, H.*; Sakaki, Koji*; Saita, Itoko*; Enoki, Hirotoshi*; Noguchi, Kazuo*; Machida, Akihiko; Watanuki, Tetsu; Nakamura, Yumiko*
International Journal of Hydrogen Energy, 39(20), p.10546 - 10551, 2014/07
Times Cited Count：13 Percentile：32.39(Chemistry, Physical)The effect of the vanadium content on the cyclic stability of V-Ti binary alloys was investigated. VTi, 
0.2 and 0.5 samples were hydrogenated and dehydrogenated at 410 K and 553 K respectively, for more than 100 times. During hydrogen cycling, reduction in the reversible hydrogen storage capacity was clearly observed from both samples. In addition, the shape of the pressure-composition-isotherm curves was significantly altered over the testing cycle period; the absorption and desorption plateaus got markedly inclined and the hysteresis became evidently smaller. We found that even after the hydrogen storage capacity of VTi was significantly reduced, at low enough temperature VTi was able to absorb hydrogen as much as it did at the first cycle.
Hasegawa, Kazuo; Ouchi, Nobuo; Chishiro, Etsuji; Kako, Eiji*; Noguchi, Shuichi*; Ouchi, Norihito*; Shishido, Toshio*; Tsuchiya, Kiyosumi*
Proceedings of 34th ICFA Advanced Beam Dynamics Workshop on High Power Superconducting Ion, Proton and Multi-Species Linacs (HPSL 2005) (Internet), 5 Pages, 2005/00
no abstracts in English
Ao, Hiroyuki; Akikawa, Hisashi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Noguchi, Shuichi*; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.75 - 77, 2004/00
The J-PARC (Japan Proton Accelerator Research Complex) LINAC will be commissioned with energy of 181-MeV using 50-keV ion source, 3-MeV RFQ, 50-MeV DTL and 181-MeV SDTL (Separated DTL) on September 2006. It is planed to be upgraded by using a 400-MeV ACS (Annular Coupled Structure), which is a high-beta structure most suitable for the J-PARC, in a few years from the commissioning. The first ACS type cavity, which will be used as the first buncher between the SDTL and the ACS, is under fabrication. Detailed design and tuning procedure of ACS cavities has been studied with RF simulation analysis and cold-model measurements. The results of cold-model measurements, fabrication status, and related development items are described in this paper.
Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 6 Pages, 2003/04
no abstracts in English
Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu*; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.
Proceedings of 21st International Linear Accelerator Conference, p.488 - 490, 2003/00
Development of a superconducting proton linac is in progress in collaboration with KEK. In order to demonstrate cavity performance and to study stable accelerating field in a pulsed operation, a 600MHz superconducting cryomodule has been fabricated. The cryomodule includes two 5-cell superconducting cavities of 
=0.6 and is designed to perform 2K operation. Cold tests of the cryomodule have been performed at the temperature of 4K and 2K. In the tests, heat leak to the cavities, loaded quality factors, tuning sensitivities, frequency shifts against helium vessel pressure and Lorentz force detuning of the cavities were measured. Most of the measured data agreed with their design values, except for the heat leak and the Lorentz force detuning. As the preliminary horizontal test of the cryomodule, high power RF test has been also performed, where the surface peak fields of 10 and 16 MV/m were achieved in CW and pulsed operation, respectively. Now, the optimization of the RF control system is in progress to demonstrate stable accelerating field in a pulsed operation.
Mukugi, Ken*; Ouchi, Nobuo; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Kusano, Joichi; Mizumoto, Motoharu; Kako, Eiji*; Saito, Kenji*; Noguchi, Shuichi*
Proceedings of 25th Linear Accelerator Meeting in Japan, p.314 - 316, 2000/07
no abstracts in English
Hasegawa, Kazuo; Mizumoto, Motoharu; Ouchi, Nobuo; Noguchi, Shuichi*
KEK Proceedings 99-25, p.28 - 32, 2000/02
no abstracts in English
Ouchi, Nobuo; Mizumoto, Motoharu; Kusano, Joichi; Chishiro, Etsuji; Hasegawa, Kazuo; Akaoka, Nobuo*; Saito, Kenji*; Noguchi, Shuichi*; Kako, Eiji*; Inoue, Hitoshi*; et al.
Proceedings of 20th International Linac Conference (CD-ROM), 1 Pages, 2000/00
no abstracts in English
Ouchi, Nobuo; Kusano, Joichi; Akaoka, Nobuo*; B.Fechner*; Hasegawa, Kazuo; Takeuchi, Suehiro; Mizumoto, Motoharu; Saito, Kenji*; Noguchi, Shuichi*; *; et al.
Proc. of 1st Asian Particle Accelerator Conf. (APAC98), p.77 - 79, 1998/11
no abstracts in English
*; Hasegawa, Kazuo; Honda, Yoichiro*; Kusano, Joichi; Mizumoto, Motoharu; Mukugi, Ken*; Ouchi, Nobuo; Inoue, Hitoshi*; Noguchi, Shuichi*; Saito, Kenji*
Proceedings of 6th European Particle Accelerator Conference (EPAC98) (CD-ROM), p.734 - 736, 1998/01
no abstracts in English
Ouchi, Nobuo; Kusano, Joichi; Akaoka, Nobuo*; Takeuchi, Suehiro; Hasegawa, Kazuo; Mizumoto, Motoharu; Inoue, Hitoshi*; *; Noguchi, Shuichi*; *; et al.
Development of Large Scale Superconducting Radio Frequency (SRF) Technologies, p.50 - 55, 1998/00
no abstracts in English
Nishimura, Hideo; Magara, Masaaki; Oda, Tetsuzo; Usuda, Shigekazu; Watanabe, Kazuo; Adachi, Takeo; Noguchi, Hiroshi
Dai-18-Kai Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Nenji Taikai Hobunshu, p.71 - 78, 1997/11
no abstracts in English
Kusano, Joichi; Ouchi, Nobuo; Akaoka, Nobuo*; *; Noguchi, Shuichi*; Mukugi, Ken*; Hasegawa, Kazuo; Mizumoto, Motoharu
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.240 - 242, 1997/00
no abstracts in English
Ouchi, Nobuo; Kusano, Joichi; Akaoka, Nobuo*; Takeuchi, Suehiro; B.Fechner*; Hasegawa, Kazuo; Mizumoto, Motoharu; Inoue, Hitoshi*; *; Noguchi, Shuichi*; et al.
Proc. of 8th Workshop on RF Superconductivity, 1, p.22 - 26, 1997/00
no abstracts in English
Ouchi, Nobuo; Kusano, Joichi; Akaoka, Nobuo*; Takeuchi, Suehiro; B.Fechner*; Hasegawa, Kazuo; Mizumoto, Motoharu; Inoue, Hitoshi*; *; Noguchi, Shuichi*; et al.
Proc. of 8th Workshop on RF Superconductivity, 1, p.12 - 21, 1997/00
no abstracts in English
