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Your search keyword '"Rachi, Takeshi"' showing total 27 results
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27 results on '"Rachi, Takeshi"'

1. Choice of Paper for Multigraphene Growth on Lead Pencil Drawing

Author

Kaneko, Satoru, Motoizumi, Yu, Satoh, Kazuo, Shimizu, Yoshitada, Yasui, Manabu, Rachi, Takeshi, Kato, Chihiro, Tanaka, Satomi, Ushiyama, Mikio, Konuma, Seiji, Itou, Yuko, Endo, Tamio, Matsuda, Akifumi, and Yoshimoto, Mamoru

Subjects
Condensed Matter - Materials Science
Abstract

Graphene is prepared with a variety of methods, such as thermal decomposition of SiC, Chemical Vapor Deposition and pulsed laser deposition. We propose another method to prepare graphitic carbon by irradiating lead pencil drawn paper using femtosecond laser [Jpn. J. Appl. Phys. 55 (2016) 01AE24]. In order to evaluate electronic properties, such as resistivity and mobility, surface roughness of paper is important to evaluate thickness of lead pencil as one of principal factors. The surface roughness of variety of paper was investigated including cross section of drawing paper. Femotosecond laser irradiated the sample surface with its focus shifted from the optical focal point to enlarge the laser spot and tender irradiation., Comment: 4 pages, 4 figures

Published
2016

2. Multi Graphene Growth on Lead Pencil Drawn Sliver-Halide Print Paper Irradiated by Scanning Femtosecond Laser

Author

Kaneko, Satoru, Shimizu, Yoshitada, Rachi, Takeshi, Kato, Chihiro, Tanaka, Satomi, Naganuma, Yasuhiro, Katakura, Toru, Satoh, Kazuo, Ushiyama, Mikio, Konuma, Seiji, Itou, Yuko, Takikawa, Hirofumi, Tan, Goon, Matsuda, Akifumi, and Yoshimoto, Mamoru

Subjects
Condensed Matter - Materials Science
Abstract

A variety of paper were drawn by lead pencil with the grade between 4H through 10B. Raman spectroscopy verified both G and D peaks on all the drawing on PC print paper, PC photo paper, kent paper and paper for silver halide print. After irradiation of scanning femtosecond laser, silver halide paper drawn with 10B lead pencil remained surface flatness compared to the other papers. Raman spectroscopy on silver print paper showed a large G peak with less intensity of D peak. After irradiation of scanning femtosecond laser on silver halide paper drawn by 10B lead pencil, Raman spectroscopy showed large G peak and less intensity of D peak together with 2D peak around 2,700 /cm corresponding to the existence of multi graphene.

Published
2015
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10. Soft x-ray spectroscopy of Ba24Ge100: Electronic phase transition and Ba-atom rattling.

Author

Rachi, Takeshi, Kitajima, Masaki, Kobayashi, Kensuke, FangZhun Guo, Nakano, Takehito, Ikemoto, Yuka, Kobayashi, Keisuke, and Tanigaki, Katsumi

Subjects
*X-ray spectroscopy, *BARIUM, *PHASE transitions, *PHOTOELECTRON spectroscopy, *POLYHEDRA, *SPECTRUM analysis
Abstract

The electronic states of Ba24Ge100 are studied by soft x-ray photoelectron spectroscopy (XPS) at a high-energy photon factory. A large reduction in the density of states (DOS) at the Fermi level is clearly shown before and after the electronic phase transition at 200 K. The changes in the spectrum widths and the fine structures of the core-level Ba 4d spectra give a very reasonable indication of the Ba-atom rattlings in the clathrate polyhedra. On-resonance experiments using the excitation from Ba 3d to 4f levels display that the wave functions of Ba 5d and 6s orbitals give only a small contribution to make a Fermi surface through the hybridization with the Ge20 cluster orbitals. Importantly, reliable values of the DOS at the Fermi level NEF are successfully deduced, using two data sets of DOS obtained from high-resolution XPS and the total magnetic susceptibilities by a superconducting quantum interference device, to be 0.149 and 0.0427 states eV-1 (Ge atom)-1 for a high-temperature and for a low-temperature phase. [ABSTRACT FROM AUTHOR]

Published
2005
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11. Graphetic Growth on Pencil Drawn Paper Irradiated by Femtosecond Laser

Author

Kaneko, Satoru, primary, Satoh, Kazuo, additional, Motoizumi, Yu, additional, Shimizu, Yoshitada, additional, Rachi, Takeshi, additional, Kato, Chihiro, additional, Tanaka, Satomi, additional, Yasui, Manabu, additional, Shawuti, Shalima, additional, Can, Musa M., additional, Matsuda, Akifumi, additional, Yoshimoto, Mamoru, additional, and Endo, Tamio, additional

Published
2016
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12. Multigraphene growth on lead-pencil drawn sliver halide print paper irradiated by scanning femtosecond laser

Author

Kaneko, Satoru, primary, Shimizu, Yoshitada, additional, Rachi, Takeshi, additional, Kato, Chihiro, additional, Tanaka, Satomi, additional, Naganuma, Yasuhiro, additional, Katakura, Toru, additional, Satoh, Kazuo, additional, Ushiyama, Mikio, additional, Konuma, Seiji, additional, Itou, Yuko, additional, Takikawa, Hirofumi, additional, Tan, Goon, additional, Matsuda, Akifumi, additional, and Yoshimoto, Mamoru, additional

Published
2015
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14. Rotational Sublevels of an Ortho-Hydrogen Molecule Encapsulated in an Isotropic C-60 Cage

Author

Kohama, Yoshimitsu, Rachi, Takeshi, Jing, Ju, Li, Zhaofei, Tang, Jun, Kumashiro, Ryotaro, Izumisawa, Satoru, Kawaji, Hitoshi, Atake, Tooru, Sawa, Hiroshi, Murata, Yasujiro, Komatsu, Koichi, Tanigaki, Katsumi, Kohama, Yoshimitsu, Rachi, Takeshi, Jing, Ju, Li, Zhaofei, Tang, Jun, Kumashiro, Ryotaro, Izumisawa, Satoru, Kawaji, Hitoshi, Atake, Tooru, Sawa, Hiroshi, Murata, Yasujiro, Komatsu, Koichi, and Tanigaki, Katsumi

Published
2009

15. Rotational Sublevels of an Ortho-Hydrogen Molecule Encapsulated in an Isotropic C-60 Cage

Author

40314273, Kohama, Yoshimitsu, Rachi, Takeshi, Jing, Ju, Li, Zhaofei, Tang, Jun, Kumashiro, Ryotaro, Izumisawa, Satoru, Kawaji, Hitoshi, Atake, Tooru, Sawa, Hiroshi, Murata, Yasujiro, Komatsu, Koichi, Tanigaki, Katsumi, 40314273, Kohama, Yoshimitsu, Rachi, Takeshi, Jing, Ju, Li, Zhaofei, Tang, Jun, Kumashiro, Ryotaro, Izumisawa, Satoru, Kawaji, Hitoshi, Atake, Tooru, Sawa, Hiroshi, Murata, Yasujiro, Komatsu, Koichi, and Tanigaki, Katsumi

Abstract

From specific heat measurements in high quality H2@C60 samples performed over a broad temperature range, we obtain the smallest yet observed splitting of rotational energy sublevels of encapsulated single H2 molecules, 0.1–0.2 meV, in the nearly spherical potential well provided by highly isotropic C60 cages. Additionally, we find evidence of the quantized oscillation state of isolated H2 in the C60 cage. The minuscule splitting indicates that H2@C60 provides unprecedented opportunities to study free-molecule quantum dynamic properties.

Published
2009

17. Rotational Sublevels of an Ortho-Hydrogen Molecule Encapsulated in an IsotropicC60Cage

Author

Kohama, Yoshimitsu, primary, Rachi, Takeshi, additional, Jing, Ju, additional, Li, Zhaofei, additional, Tang, Jun, additional, Kumashiro, Ryotaro, additional, Izumisawa, Satoru, additional, Kawaji, Hitoshi, additional, Atake, Tooru, additional, Sawa, Hiroshi, additional, Murata, Yasujiro, additional, Komatsu, Koichi, additional, and Tanigaki, Katsumi, additional

Published
2009
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20. Ferromagnetic ordering in a new nickel polyborate NiB12O14(OH)10

Author

Ju, Jing, primary, Sasaki, Jun, additional, Yang, Tao, additional, Kasamatsu, Shinya, additional, Negishi, Eiichi, additional, Li, Guobao, additional, Lin, Jianhua, additional, Nojiri, Hiroyuki, additional, Rachi, Takeshi, additional, Tanigaki, Katsumi, additional, and Toyota, Naoki, additional

Published
2006
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22. Superconductivity and physical properties ofBa24Si100determined from electric transport, specific-heat capacity, and magnetic susceptibility measurements

Author

Rachi, Takeshi, primary, Yoshino, Harukazu, additional, Kumashiro, Ryotaro, additional, Kitajima, Masaki, additional, Kobayashi, Kensuke, additional, Yokogawa, Keiichi, additional, Murata, Keizo, additional, Kimura, Noriaki, additional, Aoki, Haruyoshi, additional, Fukuoka, Hiroshi, additional, Yamanaka, Syoji, additional, Shimotani, Hidekazu, additional, Takenobu, Taishi, additional, Iwasa, Yoshihiro, additional, Sasaki, Takahiko, additional, Kobayashi, Norio, additional, Miyazaki, Yuji, additional, Saito, Kazuya, additional, Guo, FangZhun, additional, Kobayashi, Keisuke, additional, Osaka, Keiichi, additional, Kato, Kenichi, additional, Takata, Masaki, additional, and Tanigaki, Katsumi, additional

Published
2005
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25. Superconductivity and physical properties of Ba24Si100 determined from electric transport, specific-heat capacity, and magnetic susceptibility measurements

Author

Rachi, Takeshi, Yoshino, Harukazu, Kumashiro, Ryotaro, Katajima, Masaki, Kobayashi, Kensuke, Yokogawa, Keiichi, Murata, Keizo, Kimura, Noriaki, Aoki, Haruyoshi, Fukuoka, Hiroshi, Yamanaka, Shoji, Shimotani, Hidekazu, Takenobu, Taishi, Iwasa, Yoshihiro, Sasaki, Takahiro, Kobayashi, Norio, Miyazaki, Yuji, Saito, Kazuya, Guo, Fang Zhun, Kobayashi, Keisuke, Osaka, Keiichi, Kato, Kenichi, Tanaka, Masaki, and Tanigaki, Katsumi

Subjects
Condensed Matter::Superconductivity
Abstract

Both Ba24Si100 and Ba24Ge100 with crystallographically identical structure are found to be superconducting at 1.4 and 0.27 K, respectively. Physical properties of this superconductor Ba24Si100 are studied by electric transport, specific heat capacity, and magnetic susceptibility measurements. The density of states at the Fermi level NEF=0.148 states eV-1(Siatom)-1 and a distinct jump of Cp at the superconducting transition temperature ΔCp=0.272JK-1mol-1 are obtained. An exponential fit of Cp below the superconducting states gives an energy gap 2Δ=0.423meV and shows that this is a superconductor having s-wave character or isotropic energy gap. On the basis of our experimental data other important physical parameters are also derived.

Published
2005

27. Sp3-network superconductors made from IVth-group elements

Author

Rachi, Takeshi, Kumashiro, Ryotaro, Fukuoka, Hiroshi, Yamanaka, Shoji, and Tanigaki, Katsumi

Subjects
*SUPERCONDUCTORS, *SUPERCONDUCTIVITY, *CARBON, *GERMANIUM, *SILICON, *PHONONS
Abstract

Abstract: Discussions are made among the polyhedral superconductors made from IVth-group elements (C, Si and Ge). Important superconducting physical parameters of Ba8Si46 are deduced from magnetic measurements and are compared to those of K3C60. Using the lower and the upper critical fields of 78 and determined by magnetization measurements, the penetration depth and the coherence length are estimated for Ba8Si46. The high density of states at the Fermi level is the most important parameter to give rise to a relatively high in Ba8Si46, while the high phonon frequency is essential for K3C60. In contrast, the experimental facts found in where and Ge imply that the rattling phonons in the open cage potentials seem to control the superconducting transition temperature. [Copyright &y& Elsevier]

Published
2006
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