Hydrological and climate changes in southeast Siberia over the last 33 kyr

Katsuta, Nagayoshi*; Ikeda, Hisashi*; Shibata, Kenji*; Kokubu, Yoko; Murakami, Takuma*; Tani, Yukinori*; Takano, Masao*; Nakamura, Toshio*; Tanaka, Atsushi*; Naito, Sayuri*; et al.

Global and Planetary Change, 164, p.11 - 26, 2018/05

https://doi.org/10.1016/j.gloplacha.2018.02.012

Paleoenvironmental and paleoclimate changes in Siberia were reconstructed by continuous, high-resolution records of chemical compositions from a sediment core retrieved from the Buguldeika Saddle, Lake Baikal, dating back to the last 33 cal. ka BP. The Holocene climate followed by a shift at ca. 6.5 cal. ka BP toward warm and dry, suggesting that the climate system transition from the glacial to interglacial state occurred. In the last glacial period, the deposition of carbonate mud from the Primorsky Range was associated with Heinrich events (H3 and H1) and the Selenga River inflow was caused by meltwater of mountain glaciers in the Khamar-Daban Range. The anoxic bottom-water during Allerod-Younger Dryas was probably a result of weakened ventilation associated with reduced Selenga River inflow and microbial decomposition of organic matters from the Primorsky Range. The rapid decline in precipitation during the early Holocene may have been a response to the 8.2 ka cooling event.

Technological study about a disposal measures of low-level radioactive waste including uranium and long-half-life radionuclides

Sugaya, Toshikatsu; Nakatani, Takayoshi; Sasaki, Toshihisa*; Nakamura, Yasuo*; Sakai, Akihiro; Sakamoto, Yoshiaki

JAEA-Technology 2016-036, 126 Pages, 2017/02

JAEA-Technology-2016-036.pdf:7.28MB

At the Radioactive Waste Management and Disposal Project Department Sector of Decommissioning and Radioactive Waste Management, we performed the technological study about the disposal measures of the low-level radioactive waste targeted for uranium-bearing waste and intermediate depth disposal-based waste occurring from the process of the nuclear fuel cycle.

Environmental impact of nitrate nitrogen in sub-surface disposal system on surface water and sensitivity analysis of distribution coefficient of nitrate ion and porosity of waste layer on the environmental safety assessments

Nakamura, Yasuo; Nakatani, Takayoshi

JAEA-Technology 2014-048, 18 Pages, 2015/03

JAEA-Technology-2014-048.pdf:7.75MB

Sodium nitrate is included bituminized waste generating from the reprocessing plant of spent fuel which is disposed of in sub-surface disposal facility. Because the sodium nitrate is soluble material in surface water, it is a concern impact on surface water. Such as non-radioactive materials are not strictly regulated by "the Law for the Regulations of Nuclear Source Material, Nuclear Fuel Material and Reactors", but should be considered by related laws and regulations according to former basic policy. Because it is regulated as nitrate nitrogen by "The Basic Environment Law", the valuation of the environmental impact on general sub-surface disposal system was carried out. As the results, the concentration of nitrate nitrogen in river water whose annual quantity of water is rather than 110m/y is below the regulated value at the small scale surface waters as evaluation point.

Gate stack technologies for silicon carbide power MOS devices

Hosoi, Takuji*; Kirino, Takashi*; Uenishi, Yusuke*; Ikeguchi, Daisuke*; Chanthaphan, A.*; Yoshigoe, Akitaka; Teraoka, Yuden; Mitani, Shuhei*; Nakano, Yuki*; Nakamura, Takashi*; et al.

Workshop digest of 2012 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices (AWAD 2012), p.22 - 25, 2012/06

Impact of interface defect passivation on conduction band offset at SiO/4H-SiC interface

Hosoi, Takuji*; Kirino, Takashi*; Chanthaphan, A.*; Uenishi, Yusuke*; Ikeguchi, Daisuke*; Yoshigoe, Akitaka; Teraoka, Yuden; Mitani, Shuhei*; Nakano, Yuki*; Nakamura, Takashi*; et al.

Materials Science Forum, 717-720, p.721 - 724, 2012/05

https://doi.org/10.4028/www.scientific.net/MSF.717-720.721

Impact of stacked AlON/SiO gate dielectrics for SiC power devices

Watanabe, Heiji*; Kirino, Takashi*; Uenishi, Yusuke*; Chanthaphan, A.*; Yoshigoe, Akitaka; Teraoka, Yuden; Mitani, Shuhei*; Nakano, Yuki*; Nakamura, Takashi*; Hosoi, Takuji*; et al.

ECS Transactions, 35(2), p.265 - 274, 2011/05

https://doi.org/10.1149/1.3568869

Electronic structure of U(RuRh)Si studied by laser angle-resolved photoemission spectroscopy

Yoshida, Rikiya*; Nakamura, Yoshiaki*; Fukui, Masaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Okawa, Mario*; Shin, S.*; Hirai, Masaaki*; Muraoka, Yuji*; et al.

Journal of Physics; Conference Series, 273, p.012021_1 - 012021_4, 2011/02

https://doi.org/10.1088/1742-6596/273/1/012021

Signature of hidden order and evidence for periodicity modification in URuSi

Yoshida, Rikiya*; Nakamura, Yoshiaki*; Fukui, Masaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Okawa, Mario*; Shin, S.*; Hirai, Masaaki*; Muraoka, Yuji*; et al.

Physical Review B, 82(20), p.205108_1 - 205108_6, 2010/11

https://doi.org/10.1103/PhysRevB.82.205108

Development and installation of neutron detectors for engineering materials diffractometer at J-PARC

Sakasai, Kaoru; To, Kentaro; Nakamura, Tatsuya; Harjo, S.; Moriai, Atsushi; Ito, Takayoshi; Abe, Jun; Aizawa, Kazuya; Soyama, Kazuhiko; Katagiri, Masaki*; et al.

Proceedings of 19th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-19) (CD-ROM), 5 Pages, 2010/07

Neutron detectors for Engineering Materials Diffractometer, named TAKUMI, at J-PARC have been developed under international cooperation between Rutherford Appleton Laboratory (RAL) and Japan Atomic Energy Agency (JAEA), and installed successfully at the end of March 2009. The detector size was 8051370217 mm which was about 1.5 times larger than those installed in ENGIN-X, ISIS facility, RAL. Neutrons are detected based on a nuclear reaction of Li(n, )H using ZnS/LiF scintillator. The data acquisition electronics and decoding module were also manufactured. The overall performances of the detectors have been tested using various sources. The results showed that the detectors had good performances such as a position resolution of 3 mm, a neutron detection efficiency of more than 50% at 1 -neutrons, and a -ray sensitivity of less than 10 at 1.3 MeV--ray by Co source, which met the requirements of TAKUMI, and they will be presented at the meeting.

Superthermal and efficient-heating modes in the interaction of a cone target with ultraintense laser light

Nakamura, Hirotaka*; Chrisman, B.*; Tanimoto, Tsuyoshi*; Borghesi, M.*; Kondo, Kiminori; Nakatsutsumi, Motoaki*; Norimatsu, Takayoshi*; Tampo, Motonobu; Tanaka, Kazuo*; Yabuuchi, Toshinori*; et al.

Physical Review Letters, 102(4), p.045009_1 - 045009_4, 2009/01

https://doi.org/10.1103/PhysRevLett.102.045009

Interactions between a relativistic-intensity laser pulse and a cone-wire target are studied by changing the focusing point of the pulse. The pulse, when focused on the sidewall of the cone, produced superthermal electrons with an energy 10 MeV, whereas less energetic electrons 1 MeV were produced by the pulse when focused on the cone tip. Efficient heating of the wire was indicated by significant neutron signals observed when the pulse was focused on the tip. Particle-in-cell simulation results show reduced heating of the wire due to energetic electrons produced by specularly reflected light at the sidewall.