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Mesospheric ionization during substorm growth phase

村瀬 清華*; 片岡 龍峰*; 西山 尚典*; 西村 耕司*; 橋本 大志*; 田中 良昌*; 門倉 昭*; 冨川 喜弘*; 堤 雅基*; 小川 泰信*; et al.

Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06




Atmospheric resuspension of insoluble radioactive cesium bearing particles found in the difficult-to-return area in Fukushima

Tang, P.*; 北 和之*; 五十嵐 康人*; 佐藤 志彦; 畑中 恒太郎*; 足立 光司*; 木名瀬 健*; 二宮 和彦*; 篠原 厚*

Progress in Earth and Planetary Science (Internet), 9(1), p.17_1 - 17_15, 2022/03

 被引用回数:0 パーセンタイル:0.01(Geosciences, Multidisciplinary)

The deposition of insoluble radiocesium bearing microparticles (CsMPs), which were released from the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident in March 2011, has resulted in the widespread contamination of eastern Japan. Obviously, these deposited insoluble CsMPs may become the secondary contamination sources by atmospheric migration or other environmental transferring process, however, the understanding of the transport mechanism remains non-elucidation, and the relevant evidence has not been directly provided. This study, for the first time, provides the direct evidence for the resuspension of these insoluble CsMPs to the atmosphere from (1) proximity of $$^{137}$$Cs radioactivity and resemblance of the morphology and the elemental compositions of CsMPs in the samples of soil and aerosol derived from the same sampling site, (2) the special characteristics of the resuspended CsMPs of which the ratios of Na/Si, K/Si and/or Cs/Si were smaller than those from the initially released CsMPs collected at either long distance or near F1NPP, which can be ascribed to the slowly natural corrosion of CsMPs by the loss of the small amount of soluble contents in CsMPs, and (3) high CsMPs concentration of 10 granules/gram in the surface soil of our sampling site, and high resuspension frequency of CsMPs in spring when predominant suspended particles were soil dust.


Distinct variation of electronic states due to annealing in $$T'$$-type La$$_{1.8}$$Eu$$_{0.2}$$CuO$$_{4}$$ and Nd$$_{2}$$CuO$$_{4}$$

浅野 駿*; 石井 賢司*; 松村 大樹; 辻 卓也; 工藤 康太*; 谷口 貴紀*; 齋藤 真*; 春原 稔樹*; 川股 隆行*; 小池 洋二*; et al.

Physical Review B, 104(21), p.214504_1 - 214504_7, 2021/12

 被引用回数:0 パーセンタイル:0(Materials Science, Multidisciplinary)

We performed Cu K-edge X-ray absorption fine-structure measurements on $$T'$$-type La$$_{1.8}$$Eu$$_{0.2}$$CuO$$_{4}$$ (LECO) and Nd$$_{2}$$CuO$$_{4}$$ (NCO) to investigate the variation in the electronic state associated with the emergence of superconductivity due to annealing. The X-ray absorption near-edge structure spectra of as-sintered (AS) LECO are quite similar to those of AS NCO, indicating that the ground state of AS LECO is a Mott insulator. The electron density after annealing $$n_{rm AN}$$ was evaluated for both superconducting LECO and nonsuperconducting NCO and was found to be 0.40 and 0.05 electron per Cu atom, respectively. In LECO but not in NCO, extended X-ray absorption fine-structure analysis revealed a reduction in the strength of the Cu-O bond in the CuO$$_{2}$$ plane due to annealing, which is consistent with the screening effect on phonons in the metallic state. The origin of the difference in doping processes due to annealing is discussed in relation to the size of the charge-transfer gap.


High oxide-ion conductivity in Si-deficient La$$_{9.565}$$(Si$$_{5.826}$$[]$$_{0.174}$$)O$$_{26}$$ apatite without interstitial oxygens due to the overbonded channel oxygens

藤井 孝太郎*; 八島 正知*; 日比野 圭祐*; 白岩 大裕*; 福田 功一郎*; 中山 享*; 石沢 伸夫*; 花島 隆泰*; 大原 高志

Journal of Materials Chemistry A, 6(23), p.10835 - 10846, 2018/06

 被引用回数:17 パーセンタイル:64.82(Chemistry, Physical)

Apatite-type rare earth silicates are attractive materials with exhaust application such as solid-oxide fuel cells, due to its extremely high oxide-ion conductivity below 600$$^{circ}$$C. Interstitial (excess) oxygens have been believed to be responsible for the high conductivity in apatite-type materials. On the contrary, the present study clearly reveals the presence of Si vacancies [] in La-rich La$$_{9.565}$$(Si$$_{5.826}$$[]]$$_{0.174}$$)O$$_{26}$$ instead of the interstitial oxygens, by single-crystal neutron and X-ray diffraction analyses, density measurements and ${{it ab initio}}$ electronic calculations.


Mn$$_{2}$$VAl Heusler alloy thin films; Appearance of antiferromagnetism and exchange bias in a layered structure with Fe

土屋 朋生*; 小林 亮太*; 窪田 崇秀*; 斉藤 耕太郎*; 小野 寛太*; 大原 高志; 中尾 朗子*; 高梨 弘毅*

Journal of Physics D; Applied Physics, 51(6), p.065001_1 - 065001_7, 2018/02

 被引用回数:5 パーセンタイル:33.97(Physics, Applied)

Mn$$_{2}$$VAl Heusler alloy films were epitaxially grown on MgO(100) single-crystal substrates by ultra-high-vacuum magnetron sputtering. A2- and L21-type Mn$$_{2}$$VAl order was controlled by the deposition temperature. A2-type Mn$$_{2}$$VAl films showed no spontaneous magnetization, while L21-type Mn$$_{2}$$VAl films showed ferrimagnetic behaviour with a maximum saturation magnetization of 220 emu/cm$$^{3}$$ at room temperature (RT). An antiferromagnetic reflection was observed with neutron diffraction at RT for an A2-type Mn$$_{2}$$VAl film deposited at 400$$^{circ}$$C. A bilayer sample of the antiferromagnetic A2-type Mn$$_{2}$$VAl and Fe showed an exchange bias of 120 Oe at 10 K.


Examination of analytical method of rare earth elements in used nuclear fuel

小澤 麻由美; 深谷 洋行; 佐藤 真人; 蒲原 佳子*; 須山 賢也; 外池 幸太郎; 大木 恵一; 梅田 幹

Proceedings of 53rd Annual Meeting of Hot Laboratories and Remote Handling Working Group (HOTLAB 2016) (Internet), 9 Pages, 2016/11

For criticality safety of used nuclear fuel, it is necessary to determine amounts of such rare earth elements as gadolinium(Gd), samarium(Sm), europium(Eu) since those rare earth elements involve the isotopes having particularly large neutron absorption cross sections. However, it is difficult to measure those isotopes simultaneously by mass spectrometry because some of them have same mass numbers. Thus fine chemical separation of those rare earth elements is indispensable for accurate determination prior to measurement. The conventional separation method with anion exchange resin has been utilized in JAEA mainly for the separation of uranium and plutonium. Therefore rare earth elements such as Gd, Sm and Eu except Nd are wasted without being separated in the conventional method. The authors have examined to improve the conventional method in order to separate those rare earth elements mutually.


Preliminary conceptual design of the secondary sodium circuit-eliminated JSFR (Japan Sodium Fast Reactor) adopting a supercritical CO$$_{2}$$ turbine system, 2; Turbine system and plant size

木曽原 直之; 阪本 善彦; 小竹 庄司*

JAEA-Research 2014-016, 60 Pages, 2014/09




Preliminary conceptual design of the secondary sodium circuit-eliminated JSFR (Japan Sodium Fast Reactor) adopting a supercritical CO$$_{2}$$ turbine system, 1; Sodium/CO$$_{2}$$ heat exchanger

木曽原 直之; 阪本 善彦; 小竹 庄司*

JAEA-Research 2014-015, 33 Pages, 2014/09




幌延深地層研究計画; 平成23年度調査研究成果報告

中山 雅; 天野 健治; 常盤 哲也; 山本 陽一; 大山 卓也; 天野 由記; 村上 裕晃; 稲垣 大介; 津坂 仁和; 近藤 桂二; et al.

JAEA-Review 2012-035, 63 Pages, 2012/09




幌延深地層研究計画; 第2期中期計画(平成22年度$$sim$$平成26年度)調査研究計画書

岩月 輝希; 佐藤 治夫; 野原 壯; 棚井 憲治; 杉田 裕; 天野 健治; 藪内 聡; 大山 卓也; 天野 由記; 横田 秀晴; et al.

JAEA-Research 2011-009, 73 Pages, 2011/06




Binomial distribution function for intuitive understanding of fluence dependence of non-amorphized ion-track area

石川 法人; 大原 宏太; 太田 靖之*; 道上 修*

Nuclear Instruments and Methods in Physics Research B, 268(19), p.3273 - 3276, 2010/10

 被引用回数:10 パーセンタイル:59.22(Instruments & Instrumentation)

高エネルギーイオン(200MeV Au)を照射したCeO$$_{2}$$薄膜について電子的エネルギー伝達に伴う照射損傷をラマン分光法により解析した。CeO$$_{2}$$に起因するF2gピークのほかに、照射後に高波数側にブロードなピークが発達することがわかった。その結果は、計算による予測と同様の振る舞いであること、さらに真空熱アニールしたCeO$$_{2}$$試料と同様の振る舞いであることから、照射に伴う酸素欠損に起因すると結論付けた。


Anneal temperature effect on crystallite size and electric conductivity of LiMn$$_{2}$$O$$_{4}$$

Basar, K.*; Xianglian*; Siagian, S.*; 大原 宏太*; 佐久間 隆*; 高橋 東之*; 阿部 修実*; 井川 直樹; 石井 慶信*

Indonesian Journal of Physics, 20(1), p.9 - 11, 2009/01



Effect of Pb-Pb correlation in diffuse scattering of powder PbF$$_{2}$$

Xianglian*; Basar, K.*; 本多 宏之*; Siagian, S.*; 大原 宏太*; 佐久間 隆*; 高橋 東之*; 井川 直樹; 石井 慶信*

Solid State Ionics, 179(21-26), p.776 - 779, 2008/09

 被引用回数:2 パーセンタイル:12.5(Chemistry, Physical)



Studies of super-critical CO$$_{2}$$ gas turbine power generation fast reactor(Contract research, Translated document)

木曽原 直之; 小竹 庄司; 阪本 善彦

JAEA-Review 2008-040, 67 Pages, 2008/08


(1)超臨界炭酸ガスタービンシステムを採用した2次ナトリウム系削除型SFRプラントの設計を行った。発電効率は約42%であり、2次ナトリウム系及び蒸気システムを保有するSFRに比べ、原子炉建屋容積は約20%低減する。(2)超臨界炭酸ガスループを模擬した試験装置を製作した。臨界点近傍で圧縮機の高い効率が得られることを確認した。PCHE再生熱交換器の温度効率は98-99%であり、高い伝熱性能を示した。運転性試験では、不安定現象は発生しなかった。(3)ナトリウムと炭酸ガスの反応試験を行った。連続的な反応は、570-580$$^{circ}$$C以上で発生し、反応生成物はNa$$_{2}$$CO$$_{3}$$とCOであった。反応熱は50-75kJ/Na-molであった。(4)シェルアンドチューブ型ナトリウム/炭酸ガス熱交換器における、伝熱管1本ギロチン破断時の安全解析を行った。この結果、1次ナトリウム系の圧力最大値は構造健全性に影響ないこと,炉心への気泡移行による反応度上昇も炉心安全に影響のないことがわかった。また反応生成物による炉心閉塞しない見通しである。(5)超臨界炭酸ガス環境下において材料腐食試験を行った。600$$^{circ}$$C-5000hrでの12Cr鋼、及び316FRの腐食量はそれぞれ、180g/m$$^{3}$$, 5g/m$$^{3}$$であり、316FRは高い耐食性を示した。


Study of structural change in CeO$$_{2}$$ irradiated with high-energy ions by means of X-ray diffraction measurement

石川 法人; 知見 康弘; 道上 修*; 太田 靖之*; 大原 宏太; Lang, M.*; Neumann, R.*

Nuclear Instruments and Methods in Physics Research B, 266(12-13), p.3033 - 3036, 2008/06

 被引用回数:38 パーセンタイル:92.02(Instruments & Instrumentation)



Microbeam system for heavy ions from cyclotron to irradiate living cells

横田 渉; 小原 祥裕; 荒川 和夫

Proceedings of 36th ICFA Advanced Beam Dynamics Workshop (NANOBEAM 2005) (CD-ROM), 6 Pages, 2005/10



Surface oxidation and tribological properties of a hydrogenated DLC exposed to a simulated low earth orbit space environment

田川 雅人*; 浅田 英俊*; 横田 久美子*; 大原 久則*; 中東 孝浩*; 寺岡 有殿; Martin, J. M.*; Belin, M.*

no journal, , 




横田 久美子*; 浅田 秀俊*; 田川 雅人*; 大原 久典*; 中東 孝浩*; 吉越 章隆; 寺岡 有殿; Martin, J. M.*; Belin, M.*

no journal, , 




Xianglian*; Basar, K.*; Sainer, S.*; 大原 宏太*; 佐久間 隆*; 高橋 東之*; 井川 直樹; 石井 慶信

no journal, , 




相澤 康介; 木曽原 直之; 小竹 庄司; Sherwood, D. V.*

no journal, , 


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