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Watanabe, Jin*; Araki, Yasufumi; Kobayashi, Koji*; Ozawa, Akihiro*; Nomura, Kentaro*
Journal of the Physical Society of Japan, 91(8), p.083702_1 - 083702_5, 2022/08
Times Cited Count：4 Percentile：58.88(Physics, Multidisciplinary)We investigate magnetic orderings on kagome lattice numerically from the tight-binding Hamiltonian of electrons, governed by the filling factor and spin-orbit coupling (SOC) of electrons. We find that even a simple kagome lattice model can host both ferromagnetic and noncollinear antiferromagnetic orderings depending on the electron filling, reflecting gap structures in the Dirac and flat bands characteristic to the kagome lattice. Kane-Mele- or Rashba-type SOC tends to stabilize noncollinear orderings, such a magnetic spirals and 120-degree antiferromagnetic orderings, due to the effective Dzyaloshinskii-Moriya interaction from SOC. The obtained phase structure helps qualitative understanding of magnetic orderings in various kagome-layered materials with Weyl or Dirac electrons.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Itoi, Hiroyuki*; Ninomiya, Takeru*; Hasegawa, Hideyuki*; Maki, Shintaro*; Sakakibara, Akihiro*; Suzuki, Ryutaro*; Kasai, Yuto*; Iwata, Hiroyuki*; Matsumura, Daiju; Owada, Mao*; et al.
Journal of Physical Chemistry C, 124(28), p.15205 - 15215, 2020/07
Times Cited Count：8 Percentile：40.15(Chemistry, Physical)Saito, Hiroshi; Nozawa, Takashi; Takemiya, Hiroshi; Seki, Akiyuki; Matsubara, Takeshi; Saito, Kimiaki; Kitamura, Akihiro
JAEA-Review 2017-040, 34 Pages, 2018/03
JAEA-Review-2017-040.pdf:9.52MB
The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.
Takei, Satoshi*; Oshima, Akihiro*; Oyama, Tomoko; Ito, Kenta*; Sugahara, Kigen*; Kashiwakura, Miki*; Kozawa, Takahiro*; Tagawa, Seiichi*; Hanabata, Makoto*
Japanese Journal of Applied Physics, 53(11), p.116505_1 - 116505_7, 2014/11
Times Cited Count：10 Percentile：41.38(Physics, Applied)The application of natural linear polysaccharide to green resists was demonstrated for electron beam (EB) and extreme-ultraviolet (EUV) lithography. Because of the water solubility of natural polysaccharides, the water spin-coating and water-developable processes realize an environmentally friendly manufacturing process for next-generation electronic devices. The developed green resist with a weight-average molecular weight of 83,000 and 70 mol % hydroxyl groups was found to have acceptable properties such as spin-coat ability on 200 mm wafers, pillar patterns of 100-400 nm with a high EB sensitivity of 10 
C/cm
, etch selectivity with a silicon-based middle layer in CF
plasma treatment, and high prediction sensitivity to EUV region.
Takei, Satoshi*; Oshima, Akihiro*; Ichikawa, Takumi*; Sekiguchi, Atsushi*; Kashiwakura, Miki*; Kozawa, Takahiro*; Tagawa, Seiichi*; Oyama, Tomoko; Ito, Shoji*; Miyasaka, Hiroshi*
Microelectronic Engineering, 122, p.70 - 76, 2014/06
Times Cited Count：24 Percentile：76.82(Engineering, Electrical & Electronic)Biomass-derived branched sugar resist material was developed for environmentally-friendly electron beam lithography (EBL). The developed resist enables organic solvent-free water-developable process. The resist performance was evaluated using 75 keV EBL system. Lines of 50-200 nm were fabricated with high sensitivity of 7 C/cm. The resist is developable in pure water at 23 
C for 60 s, and it has acceptable CF etch selectivity.
113 of the 113th elementMorita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.
Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10
Times Cited Count：167 Percentile：97.27(Physics, Multidisciplinary)An isotope of the 113th element, 113, was produced in a nuclear reaction with a 
Zn beam on a 
Bi target. We observed six consecutive 
decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of 
Db and 
Lr both in decay energies and decay times. This indicates that the present decay chain consisted of 113, 
Rg (Z = 111), 
Mt (Z = 109), 
Bh (Z = 107), Db (Z = 105), and Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope 113, of the 113th element.
Sawada, Shinichi; Yamaki, Tetsuya; Ozawa, Taku*; Suzuki, Akihiro*; Terai, Takayuki*; Maekawa, Yasunari
ECS Transactions, 33(1), p.1067 - 1078, 2010/10
Times Cited Count：7 Percentile：89.29(Electrochemistry)In order to investigate water transport in polymer electrolyte membranes (PEMs), we calculated the self-diffusion coefficient of water, D
, by dissipative particle dynamics (DPD) simulation. The simulation target materials are Nafion and radiation-grafted PEMs in the fully-hydrated states. D was obtained by the following steps: (1) molecular modeling with the coarse-grained particles representing groups of several atoms; (2) calculation of the water particle diffusivity, D
, in the PEMs; (3) determination of the unit time in the DPD simulation; (4) conversion of D of the PEMs into D in the standard SI unit. Interestingly, D was found to decrease with the diffusion time period, 
t, probably owing to the geometrical confinement effect by water-transport hydrophilic regions. Quantitative analysis of this D-t relationship provided us with the size of hydrophilic regions.
Sawada, Shinichi; Yamaki, Tetsuya; Ozawa, Taku*; Suzuki, Akihiro*; Terai, Takayuki*; Maekawa, Yasunari
Kobunshi Rombunshu, 67(3), p.224 - 227, 2010/03
Times Cited Count：10 Percentile：31.95(Polymer Science)We investigated for the first time the mesoscopic structure of crosslinked-polytetrafluoroethylene (cPTFE) based radiation-grafted polymer electrolyte membranes (PEMs) by using dissipative particle dynamics (DPD) simulation. Based on the molecular structures, the fully-hydrated PEM systems were constructed with the coarse-grained particles representing several atom groups. In the equilibrium state, water appeared to percolate into poly(styrene sulfonic acid) (PSSA) graft chains to give a mixed phase, separated from the hydrophobic PTFE chains. This phase-separation picture is quite different from that of Nafion, in which only water particles were gathered excluding any polymer parts (a so-called water cluster). In order to obtain a deep insight into the phase-separation structure, the radial distribution function between water particles was calculated. As a result, there were found to be small water clusters with a diameter of only 1.8 nm in the water/grafts mixture regions.
Ozawa, Masaki; Kawabe, Akihiro*; Mizuguchi, Koji*; Fujita, Reiko*; Sumida, Yukio*
no journal, ,
no abstracts in English
Ozawa, Masaki; Kawabe, Akihiro*; Mizuguchi, Koji*; Fujita, Reiko*; Sumida, Yukio*
no journal, ,
no abstracts in English
Sumiya, Masato; Ikeda, Koki; Sonoda, Takashi; Niizato, Tadafumi; Mikake, Shinichiro; Abe, Hironobu; Inoue, Makoto; Eguchi, Kazutoshi; Kozawa, Masachiyo; Terunuma, Akihiro; et al.
no journal, ,
no abstracts in English
Miura, Kenta*; Hanaizumi, Osamu*; Kada, Wataru*; Ozawa, Yusuke*; Inada, Kazuki*; Kubota, Atsushi*; Kawashima, Akihiro*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; et al.
no journal, ,
no abstracts in English
Rekimoto, Masafumi; Ando, Masato; Chikazawa, Yoshitaka; Kato, Atsushi; Hamano, Tomoharu; Shiohama, Yasutaka; Miyagawa, Takayuki*; Uzawa, Masayuki*; Hara, Hiroyuki*; Yamauchi, Kanau*; et al.
no journal, ,
no abstracts in English
Tanabe, Kazuhiro*; Yanagihara, Satoshi*; Iguchi, Yukihiro; Awatani, Yuto; Saruta, Koji*; Narikawa, Isao*; Yanagida, Akihiro*; Ozawa, Shingo*; Oguri, Daiichiro*
no journal, ,
no abstracts in English
Ozawa, Akihiro*; Araki, Yasufumi; Nomura, Kentaro*
no journal, ,
no abstracts in English
Ozawa, Akihiro*; Araki, Yasufumi; Nomura, Kentaro*
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