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.

Ge diffusion and bonding state change in metal/high-/Ge gate stacks and its impact on electrical properties

Hosoi, Takuji*; Hideshima, Iori*; Tanaka, Ryohei*; Minoura, Yuya*; Yoshigoe, Akitaka; Teraoka, Yuden; Shimura, Takayoshi*; Watanabe, Heiji*

Microelectronic Engineering, 109, p.137 - 141, 2013/09

https://doi.org/10.1016/j.mee.2013.03.115

Guiding and confining fast electrons by transient electric and magnetic fields with a plasma inverse cone

Lei, A. L.*; Cao, L. H.*; Yang, X. Q.*; Tanaka, Kazuo*; Kodama, Ryosuke*; He, X. T.*; Mima, Kunioki*; Nakamura, Tatsufumi; Norimatsu, Takayoshi*; Yu, W.*; et al.

Physics of Plasmas, 16(2), p.020702_1 - 020702_4, 2009/02

https://doi.org/10.1063/1.3075928

The fast electron propagation in an inverse cone target is investigated computationally and experimentally. Two-dimensional particle-in-cell simulation shows that fast electrons with substantial numbers are generated at the outer tip of an inverse cone target irradiated by a short intense laser pulse. These electrons are guided and confined to propagate along the inverse cone wall, forming a large surface current. The experiment qualitatively verifies the guiding and confinement of the strong electron current in the wall surface. The large surface current and induced strong field s are of importance for fast ignition related research.

Fast heating of cylindrically imploded plasmas by petawatt laser light

Nakamura, Hirotaka*; Sentoku, Yasuhiko*; Matsuoka, Takeshi*; Kondo, Kiminori; Nakatsutsumi, Motoaki*; Norimatsu, Takayoshi*; Shiraga, Hiroyuki*; Tanaka, Kazuo*; Kodama, Ryosuke*

Physical Review Letters, 100(16), p.165001_1 - 165001_4, 2008/04

https://doi.org/10.1103/PhysRevLett.100.165001

We produced cylindrically imploded plasmas, which have the same density-radius product of the imploded plasma R with the compressed core in the fast ignition experiment and demonstrated efficient fast heating of cylindrically imploded plasmas with an ultraintense laser light. The coupling efficiency from the laser to the imploded column was 14%-21%, implying strong collimation of energetic electrons over a distance of 300 micron of the plasma. Particle-in-cell simulation shows confinement of the energetic electrons by self-generated magnetic and electrostatic fields excited along the imploded plasmas, and the efficient fast heating in the compressed region.

Introduction to plasma fusion energy

Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.

Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03

no abstracts in English

Spatial coherence measurement of the 13.9nm Ni-like Ag soft X-ray laser pumped by a 1.5ps, 20J laser

Tang, H.; Daido, Hiroyuki; Kishimoto, Maki; Sukegawa, Kota*; Tai, R.; Mesesson, S.*; Tanaka, Momoko; Lu, P.; Kawachi, Tetsuya; Nagashima, Keisuke; et al.

Japanese Journal of Applied Physics, 42(2A), p.443 - 448, 2003/02

https://doi.org/10.1143/JJAP.42.443

no abstracts in English

Research about the long-term stability of TRU waste disposal system

Tanaka, M.*; Fujisawa, O.*; Okutsu, Kazuo*; Takamura, Hisashi*; Aoyagi, Takayoshi*

JNC TJ8400 2001-030, 82 Pages, 2001/02

JNC-TJ8400-2001-030.pdf:13.47MB

This research arranged the relation with the events (the events which happen to each part grade of disposal institution and change) produced to the characteristic in connection with low permeability and the disposal system of barrier material, such as permeability. The important events which can affect the long stability of the performance which barrier material has by that cause, and its relation were extracted. And, the physical-properties data acquisition of bentonite supposing the events considered to be generated to a disposal system in the future was carried out. The research result of this year is shown below. (1)About the events considered to affect permeability, "the present knowledge and the reseach result" and the "view of a design about a event" were arranged. And it divided and arranged the time of construction and operation, and after closure. Consequently, the subject required in order to check the long stability of TRU waste disposal system was able to be extracted. (2)In order for the research in the last year to estimate the self-seal nature of a bentonite, swelling pressure and the permeability at the time of the bentonite which generated the maximum swelling pressure under the restricted condition for Na-bentonite and Ca-bentonite 100% material re-swelling to the space produced after that were acquired. About this result, the view of effective bentonite dryness density was applied, and the self-seal performance of the assumed material (bentonite 70%, silica 30%) examined in TRU waste disposal concept examination document was evaluated. In order to check the validity of the evaluation in the last year, the self-seal performance check experiment was conducted about the silica mixture bentonite. Consequently, the soundness of a barrier system was able to be checked by the specification of H12 TRU report.

Evaluation of permeability and swelling pressure of compacted bentonite using a calcium hydroxide solution

Aoyagi, Takayoshi*; Maeda, Munehiro*; Mihara, Morihiro; Tanaka, M.*

JNC TN8400 98-002, 62 Pages, 1998/11

JNC-TN8400-98-002.pdf:3.49MB

Tests to determine the swelling pressure, permeability, compressive strength and elastic modulus of Ca-Na exchanged bentonite, Na-bentonite and Ca-bentonite at the Power Reactor and Nuclear Fuel Development Corporation have mainly used distilled water. However, disposal facilities for TRU waste will use cementateous material for packaging, backfill as well as structural support. In this case, a large amount of calcium will dissolve in groundwater flowing through the cementateous material. Therefore, it is important to investigate the mechanical properties of bentonite in calcium-rich water as part of the disposal research program for TRU waste. In order to understand the effect of the chemical composition of water on the basic mechanical properties of bentonite - part of evaluating the disposal concepts for TRU waste disposal - we tested the permeability of compacted bentonite under saturated conditions using a calcium hydroxide solution. The aqueous solution represents water dominated by the calcium component. Na-bentonite, Ca-Na exchanged bcntonite and Ca-bentonite were used for swelling pressure measurement tests and permeability testing. Measures of the maximum and equilibrium swelling pressure as well as permeability were obtained. The dry density of bentonite was varied between tests. Results show that swelling pressure and permeability are dependent on dry density. In separate tests usig Ca-bentonite, the bentonite-mixing rate was varied as an independent parameter. Results show that there is little change in the swelling pressure and permeability between tests usig calcium hydroxide solution and distilled water for all bentonite types.

None

Fukazawa, E.*; Tanaka, M.*; Yamamoto, H.*; Taira, K.*; Yamamoto, M.*; Okutsu, Kazuo*; Hane, Koji*; Aoyagi, Takayoshi*; Morikawa, Seiji*; Furuichi, Mitsuaki*

PNC TJ1100 98-006, 434 Pages, 1998/02

PNC-TJ1100-98-006.pdf:59.14MB

None

High-/Ge gate stack with an EOT of 0.56 nm by controlling high-/Ge interface reaction using ultrathin AlO interlayer

Tanaka, Ryohei*; Hideshima, Iori*; Minoura, Yuya*; Yoshigoe, Akitaka; Teraoka, Yuden; Hosoi, Takuji*; Shimura, Takayoshi*; Watanabe, Heiji*

no journal, , 

no abstracts in English

Improvement of interfacial properties of high-k/Ge gate stacks by post-metal anneal

Tanaka, Ryohei*; Hideshima, Iori*; Minoura, Yuya*; Yoshigoe, Akitaka; Teraoka, Yuden; Hosoi, Takuji*; Shimura, Takayoshi*; Watanabe, Heiji*

no journal, , 

no abstracts in English