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Kureta, Masatoshi; Yamagata, Yoji*; Miyakoshi, Ken*; Mashii, Tatsuya*; Miura, Yoshiaki*; Takahashi, Kazunori*
JAEA-Research 2022-007, 28 Pages, 2022/09
To enhance energy separation in a counter-current Ranque-Hilsch vortex tube, a newly designed hollow helical fin was inserted into the hot tube of the vortex tube. In this study, the effect of the fin on the energy separation was investigated using three types of the vortex tube, and then computational fluid dynamics (CFD) simulation has been conducted to understand the experimental results and discuss the flow structure in the vortex tube with the hollow helical fin. As a result, it was found from the experimental data that the fin effectively enhanced energy separation, and that the tube length could be shorten. When the inlet air pressure was 0.5 MPa, the maximum temperature difference from the inlet to the cold exit was 62.2C. The CFD code employing the Reynolds Stress Model (RSM) turbulence model was used to analyze the fluid dynamics in the vortex tube. As a result, it was confirmed that the temperature, velocity, and pressure distributions changed significantly at the stagnation point, and that the distributions in the tube with the fin were completely different from those without the fin. It was thought that a strong reversing helical vortex flow with small recirculating vortex structure formed between the fin end and the stagnation point on the cold exit side would enhance energy separation in the vortex tube with the hollow helical fin.
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:51 Percentile:96.49(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.
Yamaguchi, Hiroshi*; Ijichi, Ryo*; Suzuki, Yoshiyuki*; Ooka, Sachiyo*; Shimada, Keiji*; Takahashi, Naoki*; Washio, Hidetoshi*; Nakamura, Kazuyo*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; et al.
Proceedings of 42nd IEEE Photovoltaic Specialists Conference (PVSC-42) (CD-ROM), p.2407 - 2411, 2015/06
Shimazaki, Kazunori*; Kobayashi, Yuki*; Takahashi, Masato*; Imaizumi, Mitsuru*; Murashima, Mio*; Takahashi, Yu*; Toyota, Hiroyuki*; Kukita, Akio*; Oshima, Takeshi; Sato, Shinichiro; et al.
Proceedings of 40th IEEE Photovoltaic Specialists Conference (PVSC-40) (CD-ROM), p.2149 - 2154, 2014/06
The electrical performance of a glass-type space solar sheet (G-SSS) was demonstrated in space. G-SSS comprises InGaP/GaAs dual-junction and InGaP/GaAs/InGaAs triplejunction solar cells. It is lightweight solar generation sheet, less than 0.5 mm thick. It is mounted on the "HISAKI" (SPRINT-A) small scientific satellite, which was launched on September 14, 2013. The initial flight data were successfully acquired and this flight demonstration was a world-first experiment for G-SSS using III-V multi-junction thin-film solar cells. The cells demonstrated superior performance and the electrical outputs matched the flight prediction.
Morioka, Chiharu*; Shimazaki, Kazunori*; Kawakita, Shiro*; Imaizumi, Mitsuru*; Yamaguchi, Hiroshi*; Takamoto, Tatsuya*; Sato, Shinichiro; Oshima, Takeshi; Nakamura, Yosuke*; Hirako, Keiichi*; et al.
Progress in Photovoltaics; Research and Applications, 19(7), p.825 - 833, 2011/11
Times Cited Count:26 Percentile:69.77(Energy & Fuels)Takahashi, Yoshihiro*; Oki, Takahiro*; Nagasawa, Takaharu*; Nakajima, Yasuhito*; Kawanabe, Ryu*; Onishi, Kazunori*; Hirao, Toshio; Onoda, Shinobu; Mishima, Kenta; Kawano, Katsuyasu*; et al.
Nuclear Instruments and Methods in Physics Research B, 260(1), p.309 - 313, 2007/07
Times Cited Count:4 Percentile:35.33(Instruments & Instrumentation)no abstracts in English
Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Kunimaru, Takanori; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; Hama, Katsuhiro; Matsui, Hiroya; et al.
JAEA-Research 2007-044, 434 Pages, 2007/03
The Horonobe URL Project started in 2000. Research and development activities are planned over three phases, that will span a total duration of about 20 years: the 1st surface-based investigarion phase (6 years), the 2nd URL construction phase (8 years) and rhe 3rd operation phase (12 years). Geological, geophysical, geo-mechanical, hydrogeological, and hydro-geochemical investigations have been carried out during the surface-based investigation.
Makihara, Akiko*; Asai, Hiroaki*; Tsuchiya, Yoshihisa*; Amano, Yukio*; Midorikawa, Masahiko*; Shindo, Hiroyuki*; Kuboyama, Satoshi*; Onoda, Shinobu; Hirao, Toshio; Nakajima, Yasuhito*; et al.
Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.95 - 98, 2006/10
no abstracts in English
Takahashi, Kazunori*; Nakamura, Hiroyuki*; Furumoto, Shozo*; Yamamoto, Kazuyoshi; Matsumura, Akira*; Fukuda, Hiroshi*; Yamamoto, Yoshinori*
Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 1 Pages, 2004/10
We synthesized a BPA-Gd-DTPA compound, as a carrier for neutron capture therapy to be used for MRI contrast media. Pinanediol was used as the protective group for B(OH)2 group of BPA, and the BPA unit was connected to the DTPA framework through an amide bond. The biodistribution studies were performed after injection of the compound into AH109A hepatoma bearing Donryu rats. The concentrations of Gd and boron were measured by prompt g-ray analyses. The tumor uptakes (% ID/g) were 1% and 0.3% at 20 min and 60 min after injection, respectively and were higher than that of carborane-Gd-DTPA, which we previously reported. However, liver and kidney uptake was very high and tumor/blood ratio was very low (0.38) compared to that of BPA itself (ca. 3.0). Alfa autoradiogram of a tumor bearing rat showed higher concentration of boron in the tumor compared to surrounding muscle and very high in the intestine. Although tumor selectivity of the compound was higher than that of carborane-Gd-DTPA, further studies of the synthesis and in vivo evaluation of better binary compounds are continuing.
Abe, Tetsuo*; Onishi, Kazunori*; Takahashi, Yoshihiro*; Hirao, Toshio
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.157 - 160, 2004/10
no abstracts in English
Hirao, Toshio; Laird, J. S.; Onoda, Shinobu; Shibata, Toshihiko*; Wakasa, Takeshi; Yamakawa, Takeshi; Abe, Hiroshi; Takahashi, Yoshihiro*; Onishi, Kazunori*; Ito, Hisayoshi
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.105 - 109, 2004/10
no abstracts in English
Takahashi, Yoshihiro*; Shibata, Toshihiko*; Murase, Yuji*; Onishi, Kazunori*; Hirao, Toshio; Kamiya, Tomihiro
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.111 - 114, 2004/10
no abstracts in English
Takahashi, Koji; Ishitsuka, Etsuo; Moeller, C. P.*; Hayashida, Kazunori*; Kasugai, Atsushi; Sakamoto, Keishi; Hayashi, Kenichi*; Imai, Tsuyoshi
Fusion Engineering and Design, 66-68, p.473 - 479, 2003/09
Times Cited Count:11 Percentile:58.76(Nuclear Science & Technology)For the purpose to confirm the reliability of the front steering concept, tests of the front steering launcher mock-up and neutron irradiation tests of bearings for a movable mirror were carried out under the ITER conditions. The max. stress of the flexible pipes for the movable mirror was measuerd to be 60MPa, much less than the allowable stress and agree with the calculation. No degradation on the performance of bearings was obtained for the assumed fluence of ITER. The mock-up of remote steering(RS) launcher was tested and RF radiation of 0.5MW-3sec and 0.2MW-10sec over 0-10 were performed. No degradation was obseved, either. The new launcher which has the capability of wider range rf beam steering and the corrugated square waveguide with four miter bends that yield the dog-legged structure has been designed, based on the test results. It has been fabricating for high power experiments.
Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01
no abstracts in English
Takahashi, Yoshihiro*; Onishi, Kazunori*; Fujimaki, Takeshi*; Yoshikawa, Masahito
IEEE Transactions on Nuclear Science, 46(6), p.1578 - 1585, 1999/12
Times Cited Count:23 Percentile:82.61(Engineering, Electrical & Electronic)no abstracts in English
Takahashi, Takeshi; ; ; Kashiwazaki, Hiroshi; Fujita, Tomoo; Nomura, Kazunori; Yamana, Satoshi
JNC TN8420 99-005, 48 Pages, 1999/01
None
Takahashi, Yoshihiro*; Onishi, Kazunori*; Fujimaki, Takeshi*; Yoshikawa, Masahito
Proceedings of 3rd International Workshop on Radiation Effects on Semiconductor Devices for Space Application, p.10 - 15, 1998/00
no abstracts in English
Saito, Kazunari; Yoshikawa, Masahito; Oshima, Takeshi; Ito, Hisayoshi; Nashiyama, Isamu; Takahashi, Yoshihiro*; Onishi, Kazunori*
JAERI-Conf 97-003, p.243 - 248, 1997/03
no abstracts in English
Yoshikawa, Masahito; ; Oshima, Takeshi; Ito, Hisayoshi; Nashiyama, Isamu; Yoshida, Sadafumi*; Okumura, Hajime*; Takahashi, Yoshihiro*; Onishi, Kazunori*
Journal of Applied Physics, 80(1), p.282 - 287, 1996/07
Times Cited Count:22 Percentile:70.47(Physics, Applied)no abstracts in English
Onishi, Kazunori*; Takahashi, Yoshihiro*; ; Yoshikawa, Masahito
JAERI-Research 95-090, 40 Pages, 1996/01
no abstracts in English