Thermally altered subsurface material of asteroid (162173) Ryugu

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

https://doi.org/10.1038/s41550-020-01271-2

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.

Mach-Zehnder polymer waveguides fabricated using proton beam writing

Miura, Kenta*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; Kiryu, Hiromu*; Ozawa, Yusuke*; Takano, Katsuyoshi*; Okubo, Takeru; Yamazaki, Akiyoshi; Kada, Wataru; et al.

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 126, 2013/01

https://doi.org/10.11484/jaea-review-2012-046

Fabrication of Y-junction waveguides using proton beam writing

Miura, Kenta*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; Uehara, Masato*; Kiryu, Hiromu*; Takano, Katsuyoshi*; Okubo, Takeru; Yamazaki, Akiyoshi; Kada, Wataru; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 126, 2012/01

https://doi.org/10.11484/jaea-review-2011-043

Fabrication of polymer optical waveguides for the 1.5-m band using focused proton beam

Miura, Kenta*; Machida, Yuki*; Uehara, Masato*; Kiryu, Hiromu*; Ozawa, Yusuke*; Sasaki, Tomoyuki*; Hanaizumi, Osamu*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; et al.

Key Engineering Materials, 497, p.147 - 150, 2011/12

https://doi.org/10.4028/www.scientific.net/KEM.497.147

New type phase transition of LiRuO

Miura, Yoko*; Yasui, Yukio*; Sato, Masatoshi*; Igawa, Naoki; Kakurai, Kazuhisa

no journal, , 

no abstracts in English

Fabrication of PMMA waveguides for the 1.5-m-wavelength range by using proton beam writing

Miura, Kenta*; Machida, Yuki*; Uehara, Masato*; Hanaizumi, Osamu*; Ishii, Yasuyuki; Sato, Takahiro; Takano, Katsuyoshi; Okubo, Takeru; Yamazaki, Akiyoshi; Inoue, Aichi; et al.

no journal, , 

no abstracts in English

Single-mode PMMA waveguides for the 1.5-m wavelength range fabricated by proton beam writing

Miura, Kenta*; Machida, Yuki*; Uehara, Masato*; Hanaizumi, Osamu*; Ishii, Yasuyuki; Sato, Takahiro; Takano, Katsuyoshi; Okubo, Takeru; Yamazaki, Akiyoshi; Inoue, Aichi; et al.

no journal, , 

no abstracts in English

Crystal structures of two coupled enzymes accomplishing high-efficient biochemical synthesis of trehalose

Okazaki, Nobuo; Tamada, Taro; Miura, Yutaka*; Feese, M. D.*; Kato, Masaru*; Komeda, Toshihiro*; Takehara, Kyoko*; Kobayashi, Kazuo*; Kondo, Keiji*; Kuroki, Ryota

no journal, , 

The crystal structure of glycosyltrehalose synthase (GTSase) from the hyperthermophilic archaeum Sulfolobus shibatae DSM5389 has been determined to 2.3 A resolution by X-ray crystallography. GTSase converts the glucosidic bond between the last two glucose residues of amylose from an alpha-1,4 bond to an alpha-1,1 bond, making a non-reducing glycosyl trehaloside in the first step of the biosynthesis of trehalose. The structure of GTSase can be divided into five domains. The central domain has the (beta/alpha)8 barrel fold which is conserved in the alpha-amylase family as the catalytic domain. Three invariant catalytic carboxylic amino acids in the alpha-amylase family are also found in GTSase at positions Asp241, Glu269 and Asp460 in the (beta/alpha)8 domain. Our previous study with KM1-GTSase has been shown that the maltooligosaccharides are converted to glycosyltrehalose by an intramolecular transglycosylation mechanism.

Fabrication of PMMA film waveguides utilizing proton beam writing

Miura, Kenta*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; Machida, Yuki*; Uehara, Masato*; Kiryu, Hiromu*; Takano, Katsuyoshi*; Okubo, Takeru; Yamazaki, Akiyoshi; et al.

no journal, , 

Development of actinides co-extraction system with direct extraction process using supercritical fruid, 14; Direct extraction test of unirradiated MOX fuel

Kaji, Naoya; Kamiya, Masayoshi; Takahatake, Yoko; Oyama, Koichi; Miura, Sachiko; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*

no journal, , 

A battery of tests using MOX fuel were performed for development of actinides co-extraction system with direct extraction process using supercritical fluid. The condition that was set up based on consideration of the results of the tests under ordinary pressure, and then was made fine adjusted based on the tests with supercritical fruid. As a result, U, Pu and Am were extracted simultaneously. Comparative test confirmed that U, Pu and Am could be also extracted simultaneously with dodecane as a diluent. While the extraction test of unirradiated MOX fuel with simulated FP, U, Pu was extracted with U and Am, and the Pu residue, that was found at the extraction test of irradiated fuel, was not found. As the result of scrubbing and stripping test, it was showed that traditional extraction process design method could be applied to design scrubbing and stripping process with supercritical fluid.