Short- and middle-ranges order structures of KNbO nanocrystals

Yoneda, Yasuhiro; Kunisada, Ryoichi*; Chikada, Tsukasa*; Ueno, Shintaro*; Fujii, Ichiro*; Nagata, Hajime*; Ohara, Koji*; Wada, Satoshi*

Japanese Journal of Applied Physics, 58(SL), p.SLLA03_1 - SLLA03_7, 2019/11

https://doi.org/10.7567/1347-4065/ab37e2

Verification and validation procedures of calculation codes for determining corrosive conditions in the BWR primary cooling system based on water radiolysis and mixed potential models

Uchida, Shunsuke*; Wada, Yoichi*; Yamamoto, Seiji*; Takagi, Junichi*; Hisamune, Kenji*

Journal of Nuclear Science and Technology, 51(1), p.24 - 36, 2014/01

https://doi.org/10.1080/00223131.2013.842945

ECP in the BWR primary cooling system can be measured only in the restricted region. In order to determine ECP at any location, ECP should be evaluated by computer simulation codes consisting of water radiolysis models to determine the concentrations of corrosive radiolytic species and mixed potential models to determine ECP based on corrosive species. Mitigation of SCC crack growth rate due to decreasing ECP can be authorized by the JSME Standards, while mitigation of ECP due to hydrogen addition has not been authorized yet. In the paper, standard procedures to authorize the computer simulation codes based on the verification and validation method are proposed. The numerical justification of every code applied as a standard code should be verified and its accuracy and applicability for plant analysis should be validated. Benchmark problems for verification processes are proposed and comparison of the calculated results with the measured ones for the plant of evaluation is required.

Polarization-analyzed resonant inelastic X-ray scattering of the orbital excitations in KCuF

Ishii, Kenji; Ishihara, Sumio*; Murakami, Yoichi*; Ikeuchi, Kazuhiko*; Kuzushita, Kaori*; Inami, Toshiya; Owada, Kenji; Yoshida, Masahiro; Jarrige, I.; Tatami, Naka*; et al.

Physical Review B, 83(24), p.241101_1 - 241101_4, 2011/06

https://doi.org/10.1103/PhysRevB.83.241101

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

An Electrochemical sensor array for in-situ measurements of hydrogen peroxide concentration in high-temperature water

Uchida, Shunsuke; Sato, Tomonori; Sato, Yoshiyuki*; Wada, Yoichi*

Corrosion Monitoring in Nuclear Systems, Research and Applications (EFC 56), p.239 - 254, 2010/09

In order to determine [HO] directly in high temperature water, an electrochemical sensor array consisting of an ECP sensor and a complex impedance sensor has been developed. As a result of evaluation, it was confirmed that (1) The radii of the low frequency semicircle of Cole-Cole plots of the frequency dependent complex impedance (FDCI) data decreased as [HO]. The measured radii can be applied for determining [HO], when the stability of oxide film on the stainless surface of the sensor is maintained. (2) The performance of the sensor array has been confirmed by measuring [HO] in the high temperature high pressure hydrogen peroxide water loop. (3) Combination of ECP and FDCI sensors might be a hopeful candidate to determine [HO] in the BWR primary coolant at elevated temperature.

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

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

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/tupe091.pdf

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Resonant magnetic X-ray diffraction study on successive metamagnetic transitions in TbB

Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*

Journal of the Physical Society of Japan, 78(3), p.033707_1 - 033707_4, 2009/03

https://doi.org/10.1143/JPSJ.78.033707

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Devil's flower resulting from a successive charge disproportionation of NaVO; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Hoshako, 21(2), p.87 - 96, 2008/03

http://ci.nii.ac.jp/naid/10020476047

Devil's flower has been found in a temperature-pressure phase diagram of NaVO, which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaVO. The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.

Effects of hydrogen peroxide on oxide film formation at the surface of stainless steel in high temperature water

Sato, Tomonori; Uchida, Shunsuke; Tsukada, Takashi; Sato, Yoshiyuki*; Wada, Yoichi*; Ichigure, Kenkichi*

Proceedings of Symposium on Water Chemistry and Corrosion of Nuclear Power Plants in Asia, 2007 (CD-ROM), p.124 - 129, 2007/09

In the high temperature water containing HO, the dissolution of the oxide film formed at the surface of stainless steel was larger than that in O containing water. The oxide film at the surface of stainless steel formed in high temperature water is divided into inner and outer layers. The outer oxide layer consisted of the oxide particles. In this study, the changes in oxide particles were observed with changing exposure time. The obtained results are summarized in follows; (1) The particle density and size were changed by oxidant concentration. (2) In high [HO] condition, the large hematite particle was formed, and it caused the high electric resistance of oxide film. (3) The large dissolution rate at high [HO] resulted in a thinner oxide film with small particles and larger hematite particles. (4) The large hematite particle decreased the dissolution of the inner oxide film, while the removal of hematite particles caused the decrease of the total thickness of the oxide layer.