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Yotoriyama, Mamoru*; Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issei
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 71, 2011/01
no abstracts in English
Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Hase, Yoshihiro; Narumi, Issei
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 80, 2009/12
no abstracts in English
Hirayama, Masaaki*; Sonoyama, Noriyuki*; Abe, Takashi*; Minoura, Machiko*; Ito, Masumi*; Mori, Daisuke*; Yamada, Atsuo*; Kanno, Ryoji*; Terashima, Takahito*; Takano, Mikio*; et al.
Journal of Power Sources, 168(2), p.493 - 500, 2007/06
Times Cited Count:89 Percentile:90.13(Chemistry, Physical)A new experimental technique was developed for detecting structure changes at electrode/electrolyte interface of lithium cell using X-ray reflectometry and two-dimensional model electrodes with a restricted lattice-plane. The electrodes were constructed with an epitaxial film of LiCoO synthesized by pulsed laser deposition method. The anisotropic properties were confirmed by electrochemical measurements. X-ray reflectivity measurements indicated that the impurity layer existed on the as-grown LiCoO was dissolved and a new SEI layer with lower density was formed after soaking into the electrolyte. X-ray reflectivity measurements indicated that the surface roughness of the intercalation (1 1 0) plane increased with applying voltages, while no significant changes in surface morphology were observed for the intercalation non-active (0 0 3) plane during the pristine stage of the charge-discharge process.
Hoesch, M.*; Fukuda, Tatsuo; Mizuki, Junichiro; Takenouchi, Tomohiro*; Kawarada, Hiroshi*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Nagao, Masanori*; Takano, Yoshihiko*
Physical Review B, 75(14), p.140508_1 - 140508_4, 2007/04
Times Cited Count:35 Percentile:77.41(Materials Science, Multidisciplinary)We observed phonon dispersions using inelastic X-ray scattering from CVD-grown high quality superconducting (=4.2 K) boron-doped and non-doped diamonds. By comparing these two, we found almost no change in the acoustic branch along both [111] and [001] directions. On the other hand, strong softening were observed in the optical branch of the boron-doped diamond in both directions: about 2 meV at Brillouin zone boundary and 8 meV at zone center ( point). From this result we estimated the electron-phonon coupling factor =0.33, and this supports theoretical models suggesting a phonon-mediated pairing mechanism via coupling of optical phonon modes to Fermi surfaces around the point.
Nakano, Junichi; Miwa, Yukio; Koya, Toshio; Tsukada, Takashi
Journal of Nuclear Materials, 329-333(Part1), p.643 - 647, 2004/08
Times Cited Count:9 Percentile:52.57(Materials Science, Multidisciplinary)To study effects of minor elements on the irradiation assisted stress corrosion cracking (IASCC), high purity Type 304 and 316 stainless steels (SSs) were fabricated and added minor elements, Si or C. After neutron irradiation to 3.510n/m (E1MeV), the slow strain rate tests (SSRT) for the irradiated specimens was conducted in oxygeneted high purity water at 561 K. Fracture surface of the specimens was examined using the scanning electron microscope (SEM) after the SSRT. Fraction of intergranular stress corrosion cracking (IGSCC) on the fracture surface after the SSRT increased with netron fluence. Suppression of irradiation hardening and increase of peiod to SCC fracture as benefitical effects of the additional elements, Si or Mo, were not observed obviously. In high purity SS added C, fraction of IGSCC was the smallest in the all SSs, although irraidiation hardening level was the largest in the all SSs. Addition of C suppressed the susceptibility to IGSCC.
Igashira, Masayuki*; Shibata, Keiichi; Takano, Hideki*; Yamano, Naoki*; Matsunobu, Hiroyuki*; Kitao, Kensuke*; Katakura, Junichi; Nakagawa, Tsuneo; Hasegawa, Akira; Iwasaki, Tomohiko*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.128 - 139, 2004/03
no abstracts in English
Nakano, Junichi; Tsukada, Takashi; Tsuji, Hirokazu; Terakado, Shogo; Koya, Toshio; Endo, Shinya
JAERI-Tech 2003-092, 54 Pages, 2004/01
Irradiation assisted stress corrosion cracking (IASCC) is a degradation phenomenon caused by synergy of neutron radiation, aqueous environment and stress on in-core materials, and it is an important issue in accordance with increase of aged light water reactors. Isolating crack initiation stage from crack growth stage is very useful for the evaluation of the IASCC behavior. Hence facility for in-situ observation during slow strain rate test (SSRT) for irradiated material was developed. As performance demonstrations of the facility, tensile test with in-situ observation and SSRT without observation were carried out using unirradiated type 304 stainless steel in 561 K water at 9 MPa. The following were confirmed from the results. (1) Handling, observation and recording of specimen can be operated using manipulators in the hot cell. (2) In-situ observation can be performed in pressurized high temperature water and flat sheet type specimen is suitable for the in-situ observation. (3) Test condition can be kept constantly and data can be obtained automatically for long test period.
Akao, Tadahiro*; Azuma, Yusuke; Usuda, Manabu; Nishihata, Yasuo; Mizuki, Junichiro; Hamada, Noriaki*; Hayashi, Naoaki*; Terashima, Takahito*; Takano, Mikio*
Physical Review Letters, 91(15), p.156405_1 - 156405_4, 2003/10
Times Cited Count:34 Percentile:79.55(Physics, Multidisciplinary)X-ray anomalous diffraction, together with a band structure calculation, was employed to obtain a quantitative comprehension of the charge-ordering state in a single-crystalline CaFeO thin film. The experimental results show a characteristic energy dispersion of the near inhibited reflection at 150, implying Fe atoms split into two distinct states. The energy dispersion is in good agreement with the calculated spectrum based on LDA+U scheme. The calculation reveals an electronic configuration of the Fe 3d orbital follows a localization in the oxygen orbital surrounds one of the distinct Fe atoms.
Shibata, Keiichi; Kawano, Toshihiko*; Nakagawa, Tsuneo; Iwamoto, Osamu; Katakura, Junichi; Fukahori, Tokio; Chiba, Satoshi; Hasegawa, Akira; Murata, Toru*; Matsunobu, Hiroyuki*; et al.
Journal of Nuclear Science and Technology, 39(11), p.1125 - 1136, 2002/11
Times Cited Count:669 Percentile:96.97(Nuclear Science & Technology)Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL-3.2.
Tasaka, Kanji; Katakura, Junichi; Ihara, Hitoshi; Yoshida, Tadashi*; Iijima, Shungo*; Nakashima, Ryuzo*; Nakagawa, Tsuneo; Takano, Hideki
JAERI 1320, 253 Pages, 1990/09
no abstracts in English
Fukuda, Tatsuo; Hoesch, M.*; Takenouchi, Tomohiro*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A.*; Nagao, Masanori*; Takano, Yoshihiko*; Kawarada, Hiroshi*; Mizuki, Junichiro
no journal, ,
Diamond is well known for its maximum hardness, large energy gap, high thermal conductivity, and so on. In addition to these, the superconductivity was discovered recently in boron doped (B-doped) diamond, and this was soon confirmed by other groups. We performed inelastic X-ray scattering experiments at BL35XU of SPring-8 to measure phonons in a highly B-doped CVD grown diamond having superconducting transition at 4.2 K. By comparing the experimental results with those from nitrogen doped CVD grown diamond and/or pure diamond, we found that the optical modes are softened especially at around the Brillouin zone center along with a strong broadening, while the acoustic modes do not show both softening and broadening. This confirms the strong electron-phonon coupling in superconducting diamond.
Yotoriyama, Mamoru*; Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issei
no journal, ,
no abstracts in English
Yoshii, Kenji; Hayashi, Naoaki*; Matsumura, Daiju; Kusano, Shogo*; Mizumaki, Masaichiro*; Mizuki, Junichiro*; Takano, Mikio*
no journal, ,
We have investigated the magnetocaloric effect of BaFeO and related materials. The substitutions at Ba and Fe sites was found to lead to a suppression of ground-state antiferromagnetic ordering. Hence, hysteretic losses are suppressed by the substitution, a property which is favorable to practical application. From EXAFS measurements using synchrotron radiation, BaFeO involves a local structural distortion around Fe, whereas such behavior is suppressed by the substitutions. This may be related to the suppression of antiferromagnetic state, whose details will be presented at the conference.