Watershed-geochemical model to simulate dissolved and particulate Cs discharge from a forested catchment

Sakuma, Kazuyuki; Hayashi, Seiji*; Yoshimura, Kazuya; Kurikami, Hiroshi; Malins, A.; Funaki, Hironori; Tsuji, Hideki*; Kobayashi, Takamaru*; Kitamura, Akihiro; Iijima, Kazuki

Water Resources Research, 58(8), p.e2021WR031181_1 - e2021WR031181_16, 2022/08

https://doi.org/10.1029/2021WR031181

Radio frequency plasma transition caused by gas puffing and/or direct current biasing using multiturn internal antenna

Yamauchi, Toshihiko; Kobayashi, Seiji*; Sugibayashi, Hideyuki*; Tachibana, Toshiyuki*; Naito, Shunya*; Kanno, Yoshinori*; Hiruta, Toshihito

Japanese Journal of Applied Physics, 51(1), p.01AA02_1 - 01AA02_7, 2012/01

https://doi.org/10.1143/JJAP.51.01AA02

In the beginning of this study, the RF (radio frequency) plasma by the internal antenna which is in contrast to that of the external antenna, was considered for the transition from the charged coupled plasma (CCP) to the inductively coupled plasma (ICP) not to be observed. On the contrary, in our plasma experiment by using the internal multi-turn RF antenna, the transition phenomenon was observed at the extent of 40 W in RF power. In this experiment, the relation between the gas pressure and the RF power on the transition from CCP to ICP indicated almost the same characteristic as Paschen's law. But the transition physics, or the absorption mechanism of RF power based on the collision dumping, was strongly complex. We have experimentally represented the CCP-ICP transition to study the physics using the original physical technique. Firstly, we changed the CCP into the ICP by the gas control. It was considered that the increase of the electron temperature caused the transition. Secondly, the decrease of gas pressure displayed the same meaning with the longer period of the self-pulse transition. Thirdly, the self-bias caused by RF power and the external bias applied between the RF antenna and the stage were described for the transition physics.

Study on availability of GPU for scientific and engineering calculations

Sakamoto, Kensaku; Kobayashi, Seiji*

JAEA-Testing 2009-001, 32 Pages, 2009/07

JAEA-Testing-2009-001.pdf:6.86MB

Recently, the number of scientific and engineering calculations is increasing. It is said that GPUs (Graphic Processing Units) have much higher peak floating-point processing power and memory bandwidth than CPUs (Central Processing Units). We have studied the effectiveness of GPUs by applying them to fundamental scientific and engineering calculations with CUDA (Compute Unified Device Architecture) development tools. The results have shown as follow; (1) GPGPU (General-Purpose computations on GPUs) is effective for such calculations as matrix operation, FFT (Fast Fourier Transform) and CFD (Computational Fluid Dynamics) in nuclear research region. (2) Highly-advanced programming is required for bringing out high performance of GPUs and double-precision. (3) ECC (Error Correction Code) in graphic memory systems supports are inadequate.

Advanced ceramics synthesized by inductively coupled plasma with inner RF antenna

Nakagaki, Keita; Yamauchi, Toshihiko; Kanno, Yoshinori*; Kobayashi, Seiji*

Japanese Journal of Applied Physics, 47(1), p.797 - 799, 2008/01

https://doi.org/10.1143/JJAP.47.797

The CVD system by 27.12 MHz RF heating plasma discharge was developed to investigate the synthesis of the advanced ceramics, particularly diamond. Our system was unique, whose four turns RF antenna coil was installed inside of chamber. Here, we found the interesting physical behavior for the first time which the charge coupled plasma (CCP) changed to the inductively coupled plasma (ICP) suddenly at the threshold power. The plasma characteristics which were measured by the double probe were Te10 eV and ne 10E11 cm suitable for the dissociation. No impurity was observed in plasma, judging from the spectroscopic measurement. The ball-like diamond was synthesized on the silicon (Si) substrate by the low power RF heating plasma.

Dissociation characteristics of light absorbed dioxin analogues calculated by density functional theory

Yamauchi, Toshihiko; Kobayashi, Seiji*; Ito, Shinichi*; Yamazaki, Kazuhiko; Kamei, Yasutaka*; Kanno, Yoshinori*

Kankyo Kagakkai-Shi, 19(6), p.507 - 515, 2006/11

https://doi.org/10.11353/sesj1988.19.507

Using DFT two benzene rings in Co-PCB are found to be twisted on the bond axis, whose angle is 37.8 in Co-PCB(3,3,4,4,5), and it is 90 in PCB(1,1,2,2,3,3,4,4,5,5), and two benzene rings of TCDD or TCDF are in the same plane. Next, the dissociation of chlorine atom from dioxin is realized using the violet light below 318 nm as the bond dissociation energy 3.83.9 eV estimated by the energy difference between the dioxin and the chlorine atom plus dioxin radical. The orbital bond energy is estimated to be 4.15.5 eV, and the zero-point energy is also estimated to be 0.381.65 eV. The bond dissociation energy is inverse proportion to the number of chlorine atoms in dioxins. On the other hand, the dissociation reaction by the extract of chlorine using hydrogen atom is successfully analysed. The reaction times of dechlorination, or the extract reaction of chlorine and the photolytic process, are 2240 fs.

Experimental study on accelerator driven subcritical reactor, JAERI's nuclear research promotion program, H12-031 (Contract research)

Shiroya, Seiji*; Misawa, Tsuyoshi*; Unesaki, Hironobu*; Ichihara, Chihiro*; Kobayashi, Keiji*; Nakamura, Hiroshi*; Shin, Kazuo*; Imanishi, Nobutsugu*; Kanazawa, Satoshi*; Mori, Takamasa

JAERI-Tech 2004-025, 93 Pages, 2004/03

JAERI-Tech-2004-025.pdf:6.69MB

In view of the future plan of Research Reactor Institute, Kyoto University, the present study consisted of (1) the transmission experiments of high energy neutrons through materials, (2) experimental simulation of ADSR using the Kyoto University Critical Assembly(KUCA), and (3) conceptual neutronics design study on KUR type ADSR using the MCNP-X code. Through the present study, valuable knowledge on the basic nuclear characteristics of ADSR, which is indispensable to promote the study on ADSR, was obtained both theoretically and experimentally. For the realization of ADSR, it is considered to be necessary to accumulate results of research steadily. For this purpose, it is inevitable (1) to compile the more precise nuclear data for the wide energy range, (2) to establish experimental techniques for reactor physics study on ADSR including subcriticality measurement and absolute neutron flux measurement, and (3) to develop neutronics calculation tools which take into account the neutron generation process by the spallation reaction and the delayed neutron behavior.

ITER engineering design

Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01

http://ci.nii.ac.jp/naid/40004988703

no abstracts in English

Development of port plug handling tractor for ITER

Ise, Hideo*; Izaki, Makoto*; Oishi, Haruo*; Mori, Seiji*; Ako, Kentaro*; Moriyama, Hisashi*; Kagaya, Hiroaki*; Kobayashi, Masami*; Taguchi, Ko*; Shibanuma, Kiyoshi

FAPIG, (159), p.10 - 14, 2001/11

no abstracts in English

Comparison of biological effects induced by X-rays and heavy ions in the organotypic slice cultures of the rat cerebellum

Yoshida, Yukari*; Suzuki, Yoshiyuki*; Hamada, Nobuyuki*; Shirai, Katsuyuki*; Noda, Shinei*; Al-Jahdari, W. S.*; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi*; Kobayashi, Yasuhiko; et al.

no journal, , 

no abstracts in English

Effect of X-ray and carbon ion beam on the postnatal cerebellum in organotypic slice culture

Yoshida, Yukari*; Suzuki, Yoshiyuki*; Hamada, Nobuyuki*; Shirai, Katsuyuki*; Al-Jahdari, W. S.*; Kobayashi, Yasuhiko; Ozawa, Seiji*; Nakano, Takashi*

no journal, , 

no abstracts in English