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molecular dynamics simulations reveal the hydration structure of the radium(II) ionYamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08
Times Cited Count：9 Percentile：68.46(Multidisciplinary Sciences)no abstracts in English
Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.
Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05
Times Cited Count：6 Percentile：58.16(Multidisciplinary Sciences)no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
Hosha Kagaku, (45), p.28 - 30, 2022/03
no abstracts in English
Wei, D.*; Wang, L.*; Zhang, Y.*; Gong, W.; Tsuru, Tomohito; Lobzenko, I.; Jiang, J.*; Harjo, S.; Kawasaki, Takuro; Bae, J. W.*; et al.
Acta Materialia, 225, p.117571_1 - 117571_16, 2022/02
Times Cited Count：59 Percentile：99.75(Materials Science, Multidisciplinary)Nakamura, Keisuke; Morishita, Yuki; Takasaki, Koji; Maehata, Keisuke*; Sugimoto, Tetsuya*; Kiguchi, Yu*; Iyomoto, Naoko*; Mitsuda, Kazuhisa*
Journal of Low Temperature Physics, 193(3-4), p.314 - 320, 2018/11
Times Cited Count：0 Percentile：0(Physics, Applied)Sekiguchi, Tetsuhiro; Yokoyama, Keiichi; Uozumi, Yuki*; Yano, Masahiro; Asaoka, Hidehito; Suzuki, Shinichi; Yaita, Tsuyoshi
Progress in Nuclear Science and Technology (Internet), 5, p.161 - 164, 2018/11
For nuclear transmutation of cesium-135 (
Cs), which is long-lived fission product, we are developing selective absorbent which takes only Cs atom in, but does not CsI. In this study, absorbing property of Cs atom onto the surface of fullerene (C
) film has been investigated using synchrotron-based angle-dependent X-ray photoelectron spectroscopy (XPS). The results were compared with those of CsI. It was found that Cs penetrates into C deep bulk. In contrast, CsI deposits on shallow surface. Furthermore, XPS spectra were measured as a function of Ar
-sputtering time in order to know Cs concentration profiles in deep region. Results showed that Cs penetrates into deep region of several hundreds 
.
Sekiguchi, Tetsuhiro; Baba, Yuji; Hirao, Norie; Honda, Mitsunori; Izumi, Toshinori; Ikeura, Hiromi*
Molecular Crystals and Liquid Crystals, 622(1), p.44 - 49, 2015/12
Times Cited Count：0 Percentile：0.01(Chemistry, Multidisciplinary)The molecular orientation is one of the important factors for controlling various properties in organic semiconductor materials. Films are usually heterogeneous. Thus they exist as a mixture of microscopic domains which have a variety of orientation directions. Therefore, it is essential to observe selectively microscopic domains with different orientation direction. In this work, we have developed the photoelectron emission microscopy (PEEM) system combined with the linearly polarized vacuum ultraviolet (VUV) light or synchrotron radiation (SR) X-rays. PEEM images (FOV = ca.50 micro m) for poly(3-hexylthiophene), P3HT thin films were observed under the UV irradiation with various polarization angles, including in-plain and out-of-plain polarization. Morphologies at some bright parts are different each other. The resultant observation suggests that it enables us to distinguish oriented micro-domains with specific directions of polymer chain axis from other amorphous parts.
C level structure by 
-ray spectroscopyHosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08
Times Cited Count：14 Percentile：66.59(Physics, Multidisciplinary)Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the 
C
reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet 
was measured to be 
(stat)
(syst)keV from the direct 
transition. Excitation energies of the 
and 
states were measured to be 
, keV and 
, keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of 
hypernuclei.
Takahashi, Yoshikazu; Suwa, Tomone; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4200904_1 - 4200904_4, 2015/06
Times Cited Count：3 Percentile：20.23(Engineering, Electrical & Electronic)The Japan Atomic Energy Agency (JAEA) is responsible for procuring all amounts of Central Solenoid (CS) Conductors for ITER, including CS jacket sections. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A total of 576 Nb
Sn strands and 288 copper strands are cabled around the central spiral. The maximum operating current is 40 kA at magnetic field of 13 T. CS jacket section is circular in square type tube made of JK2LB, which is high manganese stainless steel with boron added. Unit length of jacket sections is 7 m and 6,300 sections will be manufactured and inspected. Outer/inner dimension and weight are 51.3/35.3 mm and around 90 kg, respectively. Eddy Current Test (ECT) and Phased Array Ultrasonic Test (PAUT) were developed for non-destructive examination. The defects on inner and outer surfaces can be detected by ECT. The defects inside jacket section can be detected by PAUT. These technology and the inspected results are reported in this paper.
Sn cable assembled with conduit for ITER central solenoidNabara, Yoshihiro; Suwa, Tomone; Takahashi, Yoshikazu; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Sakurai, Takeru; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4200305_1 - 4200305_5, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro
DV-X
Kenkyu Kyokai Kaiho, 27(1&2), p.34 - 44, 2015/03
no abstracts in English
rays-irradiationKawahara, Yutaka*; Sekiguchi, Takahiro*; Nishikawa, Yukihiro*; Nagasawa, Naotsugu
Nihon Shiruku Gakkai-Shi, 23, p.67 - 69, 2015/03
Silk aerogel has been prepared from liquid silk, and the influences of the ray-irradiation on its mechanical property have been investigated. The formation of crosslinking structure in the sericin component by the ray-irradiation should induced the hardening of the silk aerogel.
Honda, Mitsunori; Baba, Yuji; Shimoyama, Iwao; Sekiguchi, Tetsuhiro
Review of Scientific Instruments, 86(3), p.035103_1 - 035103_5, 2015/03
Times Cited Count：10 Percentile：42.73(Instruments & Instrumentation)Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Sekiguchi, Tetsuhiro
Chemical Physics, 444, p.1 - 6, 2014/09
Times Cited Count：2 Percentile：6.3(Chemistry, Physical)Silicon thin films were deposited on a sapphire and a highly oriented pyrolytic graphite (HOPG), which have atomically flat and chemically inert surfaces. The electronic and geometrical structures of the films were analyzed by polarization-dependent X-ray absorption fine structure (XAFS). It was found that the silicon K-edge XAFS spectra for ultra-thin silicon films thinner than 0.2 monolayer exhibited two distinct resonance peaks which were not observed for bulk silicon. The peaks were assigned to the resonance excitations from the Si 1s into the valence unoccupied orbitals with 
and 
characters. The average tilted angle of the orbitals was determined by the polarization dependencies of the peak intensities. It was demonstrated that direction of a part of the orbitals in silicon film is perpendicular to the surface. These results support the existence of quasi-freestanding single-layered silicon films with sp2 configuration.
Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro
Carbon, 71, p.1 - 10, 2014/05
Times Cited Count：7 Percentile：24.59(Chemistry, Physical)B and N K-edge near-edge X-ray absorption fine structure (NEXAFS) spectra of boron carbonitride (B-C-N) films prepared by ion beam deposition are interpreted by molecular orbital calculations with the core-hole effect. Model clusters with different atomic arrangements are compared in terms of photoabsorption cross section (PACS) and net charge, and they are classified into two groups, i.e., polarization and non-polarization types. PACS of 
peaks near the lowest unoccupied molecular orbital (LUMO) state increase at B K-edge and decrease at N K-edge for polarization type and vice versa for non-polarization type. Based on a comparison between experimental and theoretical results, we propose a rule for atomic arrangements of boron, carbon, and nitrogen atoms in graphite-like B-C-N. Finally, the relationship between the rule and structural stability is discussed.
Honda, Mitsunori; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie
Thin Solid Films, 556, p.307 - 310, 2014/04
Times Cited Count：5 Percentile：23.98(Materials Science, Multidisciplinary)Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Sekiguchi, Tetsuhiro
Chemical Physics Letters, 594, p.64 - 68, 2014/02
Times Cited Count：3 Percentile：10.21(Chemistry, Physical)Structures of mono-layered silicon on a highly oriented pyrolytic graphite (HOPG) have been investigated by X-ray photoelectron spectroscopy and X-ray absorption near edge structure (XANES). For the Si K-edge XANES spectrum of the 0.15 mono-layered film, two distinct peaks were observed, which were assigned to the resonant excitations from the Si 1s into the valence unoccupied orbitals with and 
characters. On the basis of the polarization dependences of the peak intensities, it was concluded that a part of the Si film lies flat on the HOPG surface, which supports the existence of two-dimensional graphene-like structure in mono-layered silicon.
Hirao, Norie; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao
Bunseki Kagaku, 63(1), p.53 - 58, 2014/01
Times Cited Count：0 Percentile：0(Chemistry, Analytical)A method for quick and real-time observations of a solid surface at nanometer scale is described. The principle of the method is as follows. Soft X-rays from a synchrotron light source are irradiated on a solid surface and the total photoelectrons are expanded and focused on a screen using electrostatic lenses. When the energy of X-rays is scanned and the brightness is plotted, we can obtain micro X-ray absorption (micro-XAFS) spectra in all regions of the image. The spacial resolution of the method was 40 nm. In order to more quickly observe a microscopic image and measure micro-XAFS spectra, the soft X-rays from the bending magnet were focused using a newly developed poly-capillary. As a result, the photon flux of 3 keV X-rays was increased about 60 time higher than that before the focusing. Using focused X-rays, we succeeded in observing one image at 10 ms for a bulk sample. We have also tried to shorten the measuring time of the micro-XAFS spectrum. For a Si-SiO
sample, it has been demonstrated that micro-XAFS spectra in all regions of an image can be obtained within 1 min. It is concluded that real-time observations of chemical-states at nanometer scale are possible by the present method.
Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Honda, Mitsunori; Izumi, Toshinori; Ikeura, Hiromi*
Photon Factory Activity Report 2013, Part B, P. 546, 2014/00
The molecular orientation is one of the important factors for controlling various properties in organic semiconductor materials. Films are usually heterogeneous. Thus they exist as a mixture of microscopic domains which have a variety of orientation directions. Therefore, it is essential to observe selectively microscopic domains with different orientation direction. In this work, we have developed the photoelectron emission microscope (PEEM) system combined with the linearly polarized vacuum ultraviolet (VUV) light or synchrotron radiation (SR) X-rays. PEEM images for poly(3-hexylthiophene), P3HT thin films were observed under synchrotron X-ray irradiation with linearly polarization. In conclusion, it was found that PEEM with polarized synchrotron can be a powerful tool that gives information of molecular orientation in nano-meter scale.
Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie
Surface Science, 612, p.77 - 81, 2013/06
Times Cited Count：9 Percentile：40.37(Chemistry, Physical)Electronic structures of thin films of silicon monoxides (SiO) deposited on a solid surface have been in-situ investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS). For thin films with less than monolayer on highly oriented pyrolytic graphite (HOPG), it was elucidated that the stable divalent silicon surely exists in the deposited SiO layer. For the Si K-edge XAFS spectrum of the SiO thin film, the energy of the core-to-valence resonance peak is located between those of the elemental silicon (Si
) and SiO (Si
). The polarization dependence of the Si K-edge XAFS spectra revealed that the SiO molecules are well-ordered and almost perpendicularly oriented on HOPG surface. The obtained well-ordered SiO films with divalent silicon will become an excellent starting material for the synthesis of low-dimensional SiO
films.
