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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.
Kokusen, Junya; Akasaka, Shingo*; Shimizu, Osamu; Kanazawa, Hiroyuki; Honda, Junichi; Harada, Katsuya; Okamoto, Hisato
JAEA-Technology 2020-011, 70 Pages, 2020/10
JAEA-Technology-2020-011.pdf:3.37MB
The Uranium Enrichment Laboratory in the Japan Atomic Energy Agency (JAEA) was constructed in 1972 for the purpose of uranium enrichment research. The smoke emitting accident on 1989 and the fire accident on 1997 had been happened in this facility. The research on uranium enrichment was completed in JFY1998. The decommissioning work was started including the transfer of the nuclear fuel material to the other facility in JFY2012. The decommissioning work was completed in JFY2019 which are consisting of removing the hood, dismantlement of wall and ceiling with contamination caused by fire accident. The releasing the controlled area was performed after the confirmation of any contamination is not remained in the target area. The radioactive waste was generated while decommissioning, burnable and non-flammable are 1.7t and 69.5t respectively. The Laboratory will be used as a general facility for cold experiments.
He neutron spin filter at J-PARCOkudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.
Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10
Times Cited Count：10 Percentile：79.13(Instruments & Instrumentation)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：259 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Sasamoto, Hiroshi; Onda, Shingo*
Geological Society Special Publications, 482, 13 Pages, 2018/09
Times Cited Count：2 Percentile：21.58(Geology)Colloid concentration is an important parameter in models of colloid-facilitated transport. The purpose of present study is to characterize colloid concentrations and colloid stability in natural groundwater from the Horonobe Underground Research Laboratory (URL) as for development of a procedure. The particle sizes of colloids in groundwaters from the Horonobe URL range from several nm to ca. 500 nm, with a mode particle size of ca. 120 nm. Evaluation of colloid stability by DLVO theory suggests that larger colloids (i.e., 
100 nm in diameter) would be more stable than smaller colloids in some groundwaters. The estimated colloid particle concentrations ranged from 2.33
10
to 1.1210
pt/mL, and mass concentrations were estimated to range from 45 to 1540 
g/L for diameters greater than 100 nm. Colloids in Horonobe groundwaters appear to be less stable, with a moderate potential for transport, than colloids investigated in similar international studies. This reduced stability may be due to relatively higher ionic strengths and moderate dissolved organic concentrations in Horonobe groundwaters compared to their international counterparts.
Zn
and UCoZnHirose, Yusuke*; Takeuchi, Tetsuya*; Honda, Fuminori*; Yoshiuchi, Shingo*; Hagiwara, Masayuki*; Yamamoto, Etsuji; Haga, Yoshinori; Settai, Rikio*; Onuki, Yoshichika
Journal of the Physical Society of Japan, 84(7), p.074704_1 - 074704_10, 2015/07
Times Cited Count：6 Percentile：45.25(Physics, Multidisciplinary)Hirose, Yusuke*; Yoshiuchi, Shingo*; Nishimura, Naoto*; Sakaguchi, Junya*; Enoki, Kentaro*; Iwakawa, Ken*; Miura, Yasunao*; Sugiyama, Kiyohiro*; Onuki, Yoshichika; Settai, Rikio*; et al.
Journal of the Korean Physical Society, 62(12), p.1858 - 1861, 2013/06
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)
(R: rare earth)Mori, Akinobu*; Ota, Hisashi*; Yoshiuchi, Shingo*; Iwakawa, Ken*; Taga, Yuki*; Hirose, Yusuke*; Takeuchi, Tetsuya*; Yamamoto, Etsuji; Haga, Yoshinori; Honda, Fuminori*; et al.
Journal of the Physical Society of Japan, 81(2), p.024720_1 - 024720_10, 2012/02
Times Cited Count：42 Percentile：83.32(Physics, Multidisciplinary)Si and YbTZn (T: Co, Rh, Ir)Onuki, Yoshichika; Yasui, Shinichi*; Matsushita, Masaki*; Yoshiuchi, Shingo*; Oya, Masahiro*; Hirose, Yusuke*; Dung, N. D.*; Honda, Fuminori*; Takeuchi, Tetsuya*; Settai, Rikio*; et al.
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA003_1 - SA003_6, 2011/12
ZnOnuki, Yoshichika; Yasui, Shinichi*; Yoshiuchi, Shingo*; Oya, Masahiro*; Matsushita, Masaki*; Hirose, Yusuke*; Takeuchi, Tetsuya*; Honda, Fuminori*; Settai, Rikio*; Sugiyama, Kiyohiro*; et al.
Journal of Physics; Conference Series, 273, p.012013_1 - 012013_4, 2011/02
Times Cited Count：1 Percentile：33.9(Physics, Condensed Matter)ZnTakeuchi, Tetsuya*; Yasui, Shinichi*; Toda, Masatoshi*; Matsushita, Masaki*; Yoshiuchi, Shingo*; Oya, Masahiro*; Katayama, Keisuke*; Hirose, Yusuke*; Yoshitani, Naohisa*; Honda, Fuminori*; et al.
Journal of the Physical Society of Japan, 79(6), p.064609_1 - 064609_15, 2010/06
Times Cited Count：42 Percentile：83.7(Physics, Multidisciplinary)
, CeCd, and PrCd with a caged crystal structureYoshiuchi, Shingo*; Takeuchi, Tetsuya*; Oya, Masahiro*; Katayama, Keisuke*; Matsushita, Masaki*; Yoshitani, Naohisa*; Nishimura, Naoto*; Ota, Hisashi*; Tateiwa, Naoyuki; Yamamoto, Etsuji; et al.
Journal of the Physical Society of Japan, 79(4), p.044601_1 - 044601_11, 2010/04
Times Cited Count：12 Percentile：59.61(Physics, Multidisciplinary)ZnYoshiuchi, Shingo*; Toda, Masatoshi*; Matsushita, Masaki*; Yasui, Shinichi*; Hirose, Yusuke*; Oya, Masahiro*; Katayama, Keisuke*; Honda, Fuminori*; Sugiyama, Kiyohiro*; Hagiwara, Masayuki*; et al.
Journal of the Physical Society of Japan, 78(12), p.123711_1 - 123711_4, 2009/12
Times Cited Count：39 Percentile：82.77(Physics, Multidisciplinary)Honda, Takashi*; Yamaguchi, Shingo*
JNC TJ8400 2003-059, 55 Pages, 2004/01
JNC-TJ8400-2003-059.pdf:2.37MB
In general, it is difficult to evaluate non-destructively the corroded states of iron-based archaeological remains, as they are fully covered by thick rust formed under ground during a long period over a hundred years. The purpose of this study is to estimate the corrosion amounts of such remains with using X-ray CT and summarize the longevity of iron in soil. It has been clarified that rust and residual metallic iron can be quantitatively divided by this technique. Therefore, it is supposed that the amounts of corrosion can be figured out on the basis of thickness and density of rust. Eight remains dug out at seven relics were analyzed. The burial periods in soil were estimated to be from 1000 to 1500 years. Metallic iron remained in six remains, and the corrosion amounts were figured out to be from 0.5 to 3 mm in these periods. In addition, the soil environments of relics were analyzed, and the relation between corrosion behaviors and environmental factors was discussed. The rust was composed of outer goethite and inner magnetite layers in normally oxidizing conditions. On the other hand, a few samples were buried in slightly oxidizing environments, and these were covered by magnetite single layers. The corrosion amount of remains in such an environment was small compared to the others.
Honda, Takashi*; Yamaguchi, Shingo*
JNC TJ8400 2003-012, 89 Pages, 2003/01
JNC-TJ8400-2003-012.pdf:5.91MB
The corrosion behaviors of iron-based archaeological remains, which were dug out in six relics in Aomori-ken and Izumotalsya-keidai-iseki, were analyzed mainly with using X-ray CT. Several samples were cut and investigated on the details of metals and oxide films. The soils were also analyzed on redox-potential, resistance, chemical contents, and others. The results indicate that metal remains in 7/14 samples. The corrosion amounts of objects of Aomori-ken were estimated to be from 1 to 4mm during 400 - 1000 years. The environments were supposed to be oxidizing. On the other hands, it is supposed that two objects in Izumotaisya-keidai-iseki were in a reducing condition. The corrosion amounts were 0.5 - 2 mm. Furthermore, the corrosion behavior of the cast gas-pipe, which had been buried for about 130 years, were evaluated. By analyzing analysis data of soil, the environment is estimated to be weak oxidizing, and the maximum graphitic corrosion depth was about 7mm.
Yoshikawa, Hideki; Ueno, Kenichi; Honda, Takashi*; Yamaguchi, Shingo*; Yui, Mikazu
9th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '03), 0 Pages, 2003/00
None
ZnKaneko, Koji; Yoshiuchi, Shingo*; Takeuchi, Tetsuya*; Honda, Fuminori*; Settai, Rikio*; Onuki, Yoshichika
no journal, ,
no abstracts in English
ZnKaneko, Koji; Yoshiuchi, Shingo*; Takeuchi, Tetsuya*; Honda, Fuminori*; Settai, Rikio*; Onuki, Yoshichika
no journal, ,
Takir, D.*; Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; et al.
no journal, ,
JAXA spacecraft and sample return mission Hayabusa2 has arrived at the near-Earth asteroid 162173 Ryugu, which is classified a primitive carbonaceous object. Here we report recent results of near-infrared spectrometer (NIRS3) on the Hayabusa2 spacecraft. The observations provide direct measurements of the surface composition of Ryugu and context for the returned samples. NIRS3 has detected a weak and narrow absorption feature centered at 2.72 micrometer across entire observed surface. This absorption feature is attributed to the presence of OH-bearing minerals. The NIRS3 observations also revealed that Ryugu is the darkest object to be observed up-close by a visiting spacecraft. The intensity of the OH feature and low albedo are consistent with thermally-and/or shock-metamorphosed, and/or carbon-rich space-weathered primitive and hydrated carbonaceous chondrites.
