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ambient on threshold voltage stability in 4H-SiC metal-oxide-semiconductor field-effect transistorsHosoi, Takuji*; Osako, Momoe*; Moges, K.*; Ito, Koji*; Kimoto, Tsunenobu*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka; Shimura, Takayoshi*; Watanabe, Heiji*
Applied Physics Express, 15(6), p.061003_1 - 061003_5, 2022/06
Times Cited Count：6 Percentile：52.89(Physics, Applied)The combination of NO annealing and subsequent post-nitridation annealing (PNA) in CO ambient for SiO/SiC structures has been demonstrated to be effective in obtaining both high channel mobility and superior threshold voltage stability in SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs). N atoms on the SiO side of the SiO/SiC interface incorporated by NO annealing, which are plausible cause of charge trapping sites, could be selectively removed by CO-PNA at 1300
C without oxidizing the SiC. CO-PNA was also effective in compensating oxygen vacancies in SiO, resulting high immunity against both positive and negative bias-temperature stresses.
Ohira, Masashi*; Katashima, Takuya*; Naito, Mitsuru*; Aoki, Daisuke*; Yoshikawa, Yusuke*; Iwase, Hiroki*; Takata, Shinichi; Miyata, Kanjiro*; Chung, U.-I.*; Sakai, Takamasa*; et al.
Advanced Materials, 34(13), p.2108818_1 - 2108818_9, 2022/01
Times Cited Count：21 Percentile：86.92(Chemistry, Multidisciplinary)
= 
one-dimensional Ising-like antiferromagnet BaCoVO
Kimura, Shojiro*; Onishi, Hiroaki; Okutani, Akira*; Akaki, Mitsuru*; Narumi, Yasuo*; Hagiwara, Masayuki*; Okunishi, Koichi*; Kindo, Koichi*; He, Z.*; Taniyama, Tomoyasu*; et al.
Physical Review B, 105(1), p.014417_1 - 014417_9, 2022/01
Times Cited Count：4 Percentile：38.08(Materials Science, Multidisciplinary)
Cs plumes from the Fukushima Daiichi Nuclear Power Plant; Evaluation of the model intercomparison data of the Science Council of JapanKitayama, Kyo*; Morino, Yu*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
Journal of Geophysical Research; Atmospheres, 123(14), p.7754 - 7770, 2018/07
Times Cited Count：27 Percentile：66.81(Meteorology & Atmospheric Sciences)We compared seven atmospheric transport model results for Cs released during the Fukushima Daiichi Nuclear Power Plant accident. All the results had been submitted for a model intercomparison project of the Science Council of Japan in 2014. We assessed model performance by comparing model results with observed hourly atmospheric concentrations of Cs, focusing on nine plumes over the Tohoku and Kanto regions. The results showed that model performance for Cs concentrations was highly variable among models and plumes. We also assessed model performance for accumulated Cs deposition. Simulated areas of high deposition were consistent with the plume pathways, though the models that best simulated Cs concentrations were different from those that best simulated deposition. The ensemble mean of all models consistently reproduced Cs concentrations and deposition well, suggesting that use of a multimodel ensemble results in more effective and consistent model performance.
Kawabata, Kuniaki; Suzuki, Kenta; Isowa, Mitsuru*; Horiuchi, Kazunori; Ito, Rintaro
Proceedings of 14th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI 2017) (USB Flash Drive), p.561 - 564, 2017/06
This paper describes the current status of the development of a simulation system for remotely operated robots. The system will be used for operator proficiency training and robot performance verification. Our purpose for developing this system is to contribute to decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The simulator system was designed using Choreonoid, a simulator development tool. The effects of view disturbances, communication failures, and so on are extended functions that are implemented on the simulator. The effects of water submergence on the physical behavior of underwater robots are also implemented. In this paper, we introduce the prototype of the robotic simulator system with the newly implemented extended functions. Some examples of system output are shown.
Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Onishi, Naofumi*; Ito, Atsushi*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Izutsu, Rui*; Minami, Yasuo*; Baba, Motoyoshi*; et al.
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890A_1 - 95890A_8, 2015/09
Times Cited Count：1 Percentile：53.94(Optics)We have improved a soft X-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (before 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft X-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.
Nishikino, Masaharu; Kawachi, Tetsuya; Hasegawa, Noboru; Ishino, Masahiko; Minami, Yasuo*; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Sato, Katsutoshi*; Faenov, A.*; et al.
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.958902_1 - 958902_7, 2015/09
Hasegawa, Noboru; Tomita, Takuro*; Nishikino, Masaharu; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Minami, Yasuo*; Baba, Motoyoshi*; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; et al.
JAEA-Conf 2015-001, p.17 - 20, 2015/07
We have succeeded in simultaneous observation of the ablation front and the expansion front with thin filmy structure in the femto-second laser ablation process of a gold target by using the 13.9 nm soft X-ray probe (incident angle to the sample 
70 deg) with soft X-ray interferometer. The dependence on the laser local fluence and materials was obtained by the comparison between gold and tungsten.
Kamiya, Kensaku; Honda, Mitsuru; Urano, Hajime; Yoshida, Maiko; Kamada, Yutaka; Ito, Kimitaka*; JT-60 Team
Physics of Plasmas, 21(12), p.122517_1 - 122517_8, 2014/12
Times Cited Count：13 Percentile：51.94(Physics, Fluids & Plasmas)Modulation Charge eXchange Recombination Spectroscopy (MCXRS) measurements with high spatial and temporal resolution have made the evaluation of the toroidal plasma flow of fully stripped carbon impurity ions in the JT-60U tokamak peripheral region (including in particular separatrix) possible with a better signal-to-noise ratio. Boundary condition of Vt imposed at the separatrix in ELMy H-mode plasmas has been identified, comparing between co- and counter-NBI discharges. The Vt value at the separatrix is not held fixed at the zero, varying with momentum input direction, but being not strongly affected by the ELM event. A non-zero Vt value at the separatrix might be connected to fast ion losses due to toroidal field ripple that results in formation of a negative radial electric field (Er) layer having almost zero (or very weak positive) Er-shear value at the separatrix. Improved understanding of physics process in pedestal structure formation for the Vt and Er is also discussed.
Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.
Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12
no abstracts in English
Kamiya, Kensaku; Matsunaga, Go; Honda, Mitsuru; Miyato, Naoaki; Urano, Hajime; Kamada, Yutaka; Ida, Katsumi*; Ito, Kimitaka*; JT-60 Team
Contributions to Plasma Physics, 54(4-6), p.591 - 598, 2014/06
Times Cited Count：6 Percentile：28.24(Physics, Fluids & Plasmas)no abstracts in English
Yabashi, Makina*; Tanaka, Hitoshi*; Tanaka, Takashi*; Tomizawa, Hiromitsu*; Togashi, Tadashi*; Nagasono, Mitsuru*; Ishikawa, Tetsuya*; Harries, J.; Hikosaka, Yasumasa*; Hishikawa, Akiyoshi*; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 46(16), p.164001_1 - 164001_19, 2013/08
Times Cited Count：72 Percentile：94.73(Optics)Kiriyama, Hiromitsu; Shimomura, Takuya; Mori, Michiaki; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Esirkepov, T. Z.; Hayashi, Yukio; et al.
Applied Sciences (Internet), 3(1), p.214 - 250, 2013/03
Times Cited Count：15 Percentile：47.32(Chemistry, Multidisciplinary)This paper reviews techniques for improving the temporal contrast and spatial beam quality in an ultra-intense laser system that is based on chirped-pulse amplification (CPA). We describe the design, performance, and characterization of our laser system, which has the potential for achieving a peak power of 600 TW. We also describe applications of the laser system in the relativistically dominant regime of laser-matter interactions and discuss a compact, high efficiency diode-pumped laser system.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.
Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07
Times Cited Count：140 Percentile：97.59(Physics, Fluids & Plasmas)Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m
or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).
Kimura, Shojiro*; Matsuda, Masaaki; Masuda, Takatsugu*; Hondo, Suguru*; Kaneko, Koji; Metoki, Naoto; Hagiwara, Masayuki*; Takeuchi, Tetsuya*; Okunishi, Koichi*; He, Z.*; et al.
Physical Review Letters, 101(20), p.207201_1 - 207201_4, 2008/11
Times Cited Count：53 Percentile：86.26(Physics, Multidisciplinary)From neutron diffraction measurements on a quasi-1D Ising-like Co
spin compound BaCo
VO
, we observed an appearance of a novel type of incommensurate ordering in magnetic fields. This ordering is essentially different from the N
el-type ordering, which is expected for the classical system, and the peculiar spin structure is caused by quantum fluctuation inherent in the quantum spin chain. A Tomonaga-Luttinger liquid (TLL) nature characteristic of the gapless quantum 1D system is responsible for the realization of the incommensurate ordering.
Saito, Kimiaki; Saito, Hidetoshi*; Kunieda, Etsuo*; Narita, Yuichiro*; Myojoyama, Atsushi*; Fujisaki, Tatsuya*; Kawase, Takatsugu*; Kaneko, Katsutaro*; Ozaki, Masahiro*; Deloar, H. M.*; et al.
Joho Shori, 48(10), p.1081 - 1088, 2007/10
no abstracts in English
Sasaki, Takuo*; Ekins-Daukes, N. J.*; Lee, H. S.*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi; Yamaguchi, Masafumi*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 7, 2007/02
no abstracts in English
Shimazaki, Kazunori*; Imaizumi, Mitsuru*; Kawakita, Shiro*; Morioka, Chiharu*; Oshima, Takeshi; Ito, Hisayoshi; Kibe, Koichi*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 5, 2007/02
no abstracts in English
Oshima, Takeshi; Miyamoto, Haruki; Imaizumi, Mitsuru*; Morioka, Chiharu*; Kawakita, Shiro*; Shimazaki, Kazunori*; Kibe, Koichi*; Kawano, Katsuyasu*; Ito, Hisayoshi
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 6, 2007/02
no abstracts in English
-ray analysis and construction of its beam lineOshima, Masumi; Toh, Yosuke; Kimura, Atsushi; Ebihara, Mitsuru*; Oura, Yasuji*; Ito, Yasuo*; Sawahata, Hiroyuki*; Matsuo, Motoyuki*
Journal of Radioanalytical and Nuclear Chemistry, 271(2), p.317 - 321, 2007/02
Times Cited Count：11 Percentile：60.18(Chemistry, Analytical)By combining neutron activation analysis with multiple -ray detection, we have proved better sensitivity and resolution for the trace element analysis than the ordinary single -ray detection method. We now try to apply the multiple -ray detection method to the prompt -ray analysis (PGA). We have established a new cold neutron beam line for PGA in Japan Research Reactor, JRR-3M, at Tokai establishment of Japan Atomic Energy Research Institute(JAERI). It consists of a beam shutter, a beam attenuator, a -ray detector array, a sample changer, and a beam stopper. We construct a high-efficiency -ray detector array specially designed for this purpose. Its performance has been evaluated with the Monte Carlo simulation code, GEANT 4.5.0.
