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Towards optimizing the performance of self-regenerating Pt-based perovskite catalysts

Jarrige, I.*; 石井 賢司; 松村 大樹; 西畑 保雄; 吉田 雅洋*; 岸 浩史*; 谷口 昌司*; 上西 真里*; 田中 裕久*; 笠井 秀明*; et al.

ACS Catalysis, 5(2), p.1112 - 1118, 2015/02

 被引用回数:11 パーセンタイル:65.79(Chemistry, Physical)

Self-regenerating automotive catalysts owe their remarkable performance to the repeated motion of the precious metal atoms in and out of the perovskite lattice under fluctuating oxidizing and reducing conditions, preventing coalescence of the metal nanoparticles. Here we use resonant inelastic X-ray scattering to characterize the occupied and unoccupied Pt 5d states in two self-regenerating Pt-perovskite catalysts, CaTi$$_{0.95}$$Pt$$_{0.05}$$O$$_3$$ and CaZr$$_{0.95}$$Pt$$_{0.05}$$O$$_3$$. Upon reduction, the element and symmetry-specific charge excitation spectra reveal a sizeable hybridization between the Pt 5d and the Ti 3d or Zr 4d states at the interface between the nanoparticles and the perovskite, which involves the occupied states and is thus invisible in X-ray absorption spectra. A correlation is found between the strength of this d-band hybridization and the proportion of Pt nanoparticles that remain buried below the surface during reduction, indicating that the motion of the Pt atoms towards the surface is hindered by this hybridization specifically, rather than by the Pt-O bonding. These results provide direct evidence that the strength of the metal-metal d-band hybridization plays a pivotal role in determining the efficiency of self-regeneration in perovskite catalysts.


Momentum-resolved resonant inelastic X-ray scattering on a single crystal under high pressure

吉田 雅洋*; 石井 賢司; Jarrige, I.*; 綿貫 徹; 工藤 一貴*; 小池 洋二*; 熊谷 健一*; 平岡 望*; 石井 啓文*; Tsuei, K.-D.*; et al.

Journal of Synchrotron Radiation, 21(1), p.131 - 135, 2014/01

 被引用回数:3 パーセンタイル:75.24(Instruments & Instrumentation)

A single-crystal momentum-resolved resonant inelastic X-ray scattering (RIXS) experiment under high pressure using an originally designed diamond anvil cell (DAC) is reported. The diamond-in/diamond-out geometry was adopted with both the incident and scattered beams passing through a 1 mm-thick diamond. This enabled us to cover wide momentum space keeping the scattering angle condition near 90$$^{circ}$$. Elastic and inelastic scattering from the diamond was drastically reduced using a pinhole placed after the DAC. Measurement of the momentum-resolved RIXS spectra of Sr$$_{2.5}$$Ca$$_{11.5}$$Cu$$_{24}$$O$$_{41}$$ at the Cu $$K$$-edge was thus successful. Though the inelastic intensity becomes weaker by two orders than the ambient pressure, RIXS spectra both at the center and the edge of the Brillouin zone were obtained at 3 GPa and low-energy electronic excitations of the cuprate were found to change with pressure.



津田 修一; 吉田 忠義; 中原 由紀夫; 佐藤 哲朗; 関 暁之; 松田 規宏; 安藤 真樹; 武宮 博; 谷垣 実*; 高宮 幸一*; et al.

JAEA-Technology 2013-037, 54 Pages, 2013/10




The Possible interplanetary transfer of microbes; Assessing the viability of ${it Deinococcus}$ spp. under the ISS environmental conditions for performing exposure experiments of microbes in the Tanpopo mission

河口 優子*; Yang, Y.*; 川尻 成俊*; 白石 啓祐*; 高須 昌子*; 鳴海 一成*; 佐藤 勝也; 橋本 博文*; 中川 和道*; 谷川 能章*; et al.

Origins of Life and Evolution of Biospheres, 43(4-5), p.411 - 428, 2013/10

 被引用回数:21 パーセンタイル:27.21(Biology)

In the Tanpopo mission, we have proposed to carry out experiments on capture and space exposure of microbes at the Exposure Facility of the Japanese Experimental Module of the International Space Station (ISS). Microbial candidates for the exposure experiments in space include ${it Deinococcus}$ spp. We have examined the survivability of ${it Deinococcus}$ spp. under the environmental conditions in ISS in orbit. A One-year dose of heavy-ion beam irradiation did not affect the viability of ${it Deinococcus}$ spp. within the detection limit. Exposure of various thicknesses of deinococcal cell aggregates to UV radiation revealed that a few hundred micrometer thick aggregate of deinococcal cells would be able to withstand the solar UV radiation on ISS for 1 year. We concluded that aggregated deinococcal cells will survive the yearlong exposure experiments. We propose that microbial cells can aggregate as an ark for the interplanetary transfer of microbes, and we named it "massapanspermia".


Three-dimensional and multienergy $$gamma$$-ray simultaneous imaging by using a Si/CdTe Compton camera

鈴木 義行*; 山口 充孝; 小高 裕和*; 島田 博文*; 吉田 由香里*; 鳥飼 幸太*; 佐藤 隆博; 荒川 和夫*; 河地 有木; 渡辺 茂樹; et al.

Radiology, 267(3), p.941 - 947, 2013/06

 被引用回数:10 パーセンタイル:52.8(Radiology, Nuclear Medicine & Medical Imaging)

Capabillity tests of 3D imaging for medical applications were performed by using a new Compton camera. $$^{18}$$F, $$^{131}$$I and $$^{67}$$Ga separately compacted into micro tubes were injected subcutaneously into a Wister rat and imaged after sacrifice of the rat (ex-vivo model). In a separate experiment $$^{111}$$In-chloride and $$^{131}$$I-Methylnorcholestenol were injected into a rat intravenously and $$^{64}$$Cu was injected into the stomach orally just before imaging (more physiological model). The Compton camera demonstrated its 3D multinuclear imaging capability by separating out the three nuclear distributions clearly in ex-vivo model. In the more physiological model, the distributions of $$^{131}$$I and $$^{64}$$Cu were clearly imaged although $$^{111}$$In was difficult to visualize due to blurring at low energy region of $$gamma$$-ray. In conclusion, our new Compton camera successfully demonstrated highly resolved multiplanar and multinuclear $$gamma$$-ray simultaneous imaging.


New result in the production and decay of an isotope, $$^{278}$$113 of the 113th element

森田 浩介*; 森本 幸司*; 加治 大哉*; 羽場 宏光*; 大関 和貴*; 工藤 祐生*; 住田 貴之*; 若林 泰生*; 米田 晃*; 田中 謙伍*; et al.

Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10

 被引用回数:126 パーセンタイル:2.53(Physics, Multidisciplinary)

113番元素である$$^{278}$$113を$$^{209}$$Bi標的に$$^{70}$$Znビームを照射する実験により合成した。観測したのは6連鎖の$$alpha$$崩壊で、そのうち連鎖の5番目と6番目は既知である$$^{262}$$Db及び$$^{258}$$Lrの崩壊エネルギーと崩壊時間と非常によく一致した。この意味するところは、その連鎖を構成する核種が$$^{278}$$113, $$^{274}$$Rg (Z=111), $$^{270}$$Mt (Z=109), $$^{266}$$Bh (Z=107), $$^{262}$$Db (Z=105)及び$$^{258}$$Lr (Z=103)であることを示している。本結果と2004年, 2007年に報告した結果と併せて、113番元素である$$^{278}$$113を曖昧さなく生成・同定したことを強く結論付ける結果となった。


Three-dimensional imaging test for a head module of a Si/CdTe Compton camera for medical application

山口 充孝; 河地 有木; 神谷 富裕; 佐藤 隆博; 鈴井 伸郎; 藤巻 秀; 小高 裕和*; 石川 真之介*; 国分 紀秀*; 渡辺 伸*; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 145, 2012/01



Development of head module for multi-head Si/CdTe Compton camera for medical applications

山口 充孝; 河地 有木; 鈴井 伸郎; 藤巻 秀; 神谷 富裕; 小高 裕和*; 石川 真之介*; 国分 紀秀*; 渡辺 伸*; 高橋 忠幸*; et al.

Nuclear Instruments and Methods in Physics Research A, 648(Suppl.1), p.S2 - S7, 2011/08

 被引用回数:1 パーセンタイル:86.72(Instruments & Instrumentation)



Counting rate performance measurement of newly developed Si/CdTe Compton camera for biological and medical applications

山口 充孝; 河地 有木; 神谷 富裕; 鈴井 伸郎; 藤巻 秀; 小高 裕和*; 石川 真之介*; 国分 紀秀*; 渡辺 伸*; 高橋 忠幸*; et al.

2010 IEEE Nuclear Science Symposium Conference Record (CD-ROM), p.2004 - 2007, 2010/10

In recent developed radionuclide-based imaging technologies utilized for biological and medical studies, wide dynamic range of radiation intensity with a good quantitative linearity is one of the most important factors. However, the linearity of a detector or a sensor generally breaks due to the dead-time increasing in high counting rate. Therefore, in case of an imaging camera, which is a large set of detectors, it is essential to measure the sensitivity profile of it varying with the radiation source intensity for correction of nonlinearity of each detector. Si/CdTe Compton camera is comprised of two layered double-sided Si strip detectors and two layered double-sided CdTe strip detectors with a four-layer laminated structure. For imaging, the source positions of $$gamma$$-rays are identified by analysing the deposited energies and the scattering angles from counted events in those of detectors. In this work, the Compton camera that was newly developed for biological and medical applications was investigated on the counting rate performance, and the sensitivity profile of this highly complicated imaging system was measured using a $$^{18}$$F point $$gamma$$-ray source. The intense source of 20 MBq was used to measure the sensitivity profiles for a wide range of counting rate in a short period. The result was compared with a calculation using a model considering the dead time of the detection system.



飛田 健次; 西尾 敏*; 榎枝 幹男; 中村 博文; 林 巧; 朝倉 伸幸; 宇藤 裕康; 谷川 博康; 西谷 健夫; 礒野 高明; et al.

JAEA-Research 2010-019, 194 Pages, 2010/08


発電実証だけでなく、最終的には経済性までを一段階で見通しうる核融合原型炉SlimCSの概念設計の成果を報告する。核融合の開発では、これまで、1990年に提案されたSSTR(Steady State Tokamak Reactor)が標準的な原型炉概念とされてきたが、本研究はSSTRより軽量化を図るため小規模な中心ソレノイドを採用して炉全体の小型化と低アスペクト比化を図り、高ベータ及び高楕円度(グリーンワルド密度限界を高めうる)を持つ炉心プラズマにより高出力密度を目指した。主要パラメータは、プラズマ主半径5.5m,アスペクト比2.6,楕円度2.0,規格化ベータ値4.3,核融合出力2.95GW,平均中性子壁負荷3MW/m$$^{2}$$とした。この炉概念の技術的成立性を、プラズマ物理,炉構造,ブランケット,超伝導コイル,保守及び建屋の観点から検討した。


Recent progress in the energy recovery linac project in Japan

坂中 章悟*; 明本 光生*; 青戸 智浩*; 荒川 大*; 浅岡 聖二*; 榎本 収志*; 福田 茂樹*; 古川 和朗*; 古屋 貴章*; 芳賀 開一*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05



Compact DEMO, SlimCS; Design progress and issues

飛田 健次; 西尾 敏; 榎枝 幹男; 川島 寿人; 栗田 源一; 谷川 博康; 中村 博文; 本多 充; 斎藤 愛*; 佐藤 聡; et al.

Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07

 被引用回数:117 パーセンタイル:1.66(Physics, Fluids & Plasmas)



Basic characteristics of a newly developed Si/CdTe Compton camera for medical imaging

河地 有木; 渡邉 茂樹; 佐藤 隆博; 荒川 和夫; 武田 伸一郎*; 石川 真之介*; 青野 博之*; 渡辺 伸*; 山口 充孝*; 高橋 忠幸*; et al.

2008 IEEE Nuclear Science Symposium Conference Record (CD-ROM), p.1540 - 1543, 2008/10

The Compton camera is a very promising medical imaging system when we consider multiple radionuclide imaging and its sensitivity, portability and compactness. We have developed a Compton camera by using Si and CdTe semiconductors for medical imaging. The prototype Compton camera head consists of a double-sided Si strip detector (DSSD) module as the scatter detector and four layered 16 CdTe pixel detector modules as the absorber detector. The DSSD has an area of 2.56$$times$$2.56 cm, a thickness of 500 $$mu$$m and a strip pitch of 400 $$mu$$m. The CdTe pixel detector has an area of 1.35$$times$$1.35 cm, a thickness of 500 $$mu$$m and a pixel size of 1.35 mm$$^{2}$$. The high-energy resolution detectors (DSSD: $$Delta$$E/E$$sim$$2.5%, CdTe: $$Delta$$E/E$$sim$$1%) enable detect the Compton scatter events of the incident $$gamma$$-rays, in consequence image radioactive multi-nuclide tracer. We evaluated distributions of sensitivity and spatial resolution, and rat study was performed with three tracers ($$^{111}$$In, $$^{131}$$I, $$^{64}$$Cu) concurrently-administered. As results, lines of point-source data indicated 4 mm spatial resolution in the center of field of view (FOV) in this experimental design, and a characteristic manner of the distributions in the Compton camera FOV was shown. The nuclides in the rat body were distinguished by the $$gamma$$-ray energies, each tracer imaged separately in vivo, and the difference in distribution among the nuclide was visualized successfully.


Design and operation of high-energy and high-average-power diode-pumped single Nd:YAG amplifier with stimulated-Brillouion-scattering phase conjugate mirror

桐山 博光; 山川 考一; 影山 進人*; 宮島 博文*; 菅 博文*; 吉田 英次*; 中塚 正大*

Japanese Journal of Applied Physics, Part 1, 44(10), p.7464 - 7471, 2005/10

 被引用回数:2 パーセンタイル:89.91(Physics, Applied)



Crystal and magnetic structure of Ca$$_{3}$$Ru$$_{2}$$O$$_{7}$$

吉田 良行*; 池田 伸一*; 松畑 洋文*; 白川 直樹*; Lee, C.-H.*; 片野 進

Physical Review B, 72(5), p.054412_1 - 054412_7, 2005/08

 被引用回数:87 パーセンタイル:6.94(Materials Science, Multidisciplinary)



360-W average power operation with a single-stage diode-pumped Nd:YAG amplifier at a 1-kHz repetition rate

桐山 博光; 山川 考一; 永井 亨; 影山 進人*; 宮島 博文*; 菅 博文*; 吉田 英次*; 中塚 正大*

Optics Letters, 28(18), p.1671 - 1673, 2003/09

 被引用回数:28 パーセンタイル:24.78(Optics)



Single-crystal growth of transition metal oxides at high pressures of several GPa

東 正樹*; 斎藤 高志*; 石渡 晋太郎*; 吉田 裕史*; 高野 幹夫*; 高坂 祐樹*; 高木 英典*; 内海 渉

Journal of Physics; Condensed Matter, 14(44), p.11321 - 11324, 2002/11

 被引用回数:7 パーセンタイル:59.62(Physics, Condensed Matter)

数万気圧の高圧下におけるX線回折実験の結果をもとに、種々の遷移金属酸化物の単結晶育成を行った。(VO)$$_{2}$$P$$_{2}$$O$$_{7}$$, CaNaCu$$_{2}$$Cl$$_{2}$$, CaFeO$$_{3}$$の結果について報告する。



中村 博文; 林 巧; 鈴木 卓美; 吉田 浩*; 西 正孝

JAERI-Research 2000-044, 24 Pages, 2000/10




Fabrication of beryllium spheres and its validation tests

吉田 浩; 榎枝 幹男; 中村 博文; 成瀬 雄二

JAERI-M 92-116, 108 Pages, 1992/08





河地 有木; 渡邉 茂樹; 佐藤 隆博; 松橋 信平; 荒川 和夫; 武田 伸一郎*; 石川 真之介*; 青野 博文*; 渡辺 伸*; 高橋 忠幸*; et al.

no journal, , 

生体内のさまざまな元素動態を同時に非侵襲的かつ定量的にイメージングする手法は、生命科学に新たな知見を与えることができる。競合する複数分子の同一個体内生理反応システムを多次元的に可視化する、粒子線治療時に照射部位から発生する微量な即発$$gamma$$線などを多角的かつ効率的にモニタリングする、などさまざまな応用研究が期待できる。原子力機構・宇宙航空研究開発機構・群馬大学では、この複数元素同時イメージングを目的とし、高エネルギー分解能を持つ半導体検出器を用いたコンプトンカメラの開発を行っている。今回の試作機は400$$mu$$mピッチのDouble-sided Si Strip Detector(DSSD)と4層の1.35mm$$^{2}$$のピクセルサイズを持つCdTe Detectorに低ノイズアナログASICを組合せて構築した、Si/CdTeコンプトンカメラである。この試作機を用いて、ファントム撮像によるコンプトンカメラ基礎特性評価データを取得し、エネルギーの異なる3核種(511keV: $$^{64}$$Cu, 364keV: $$^{131}$$I, 254keV: $$^{111}$$In)を用いたイメージング実験を行った。その結果、生体内複数核種トレーサの同時イメージングに成功し、またコンプトンカメラの特性である独特な感度分布及び分解能分布、120度以上という広視野角が明確になった。これは装置・RI・画像解析といった実験条件の最適化を容易にし、今後予定している次世代医用コンプトンカメラの開発に向けた基本設計に非常に有用な基礎データである。

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