Dynamics of water in a catalyst layer of a fuel cell by quasielastic neutron scattering

Ito, Kanae; Yamada, Takeshi*; Shinohara, Akihiro*; Takata, Shinichi; Kawakita, Yukinobu

Journal of Physical Chemistry C, 125(39), p.21645 - 21652, 2021/10

https://doi.org/10.1021/acs.jpcc.1c06014

Experimental determination of the photooxidation of aqueous I as a source of atmospheric I

Watanabe, Kosuke*; Matsuda, Shohei; Cuevas, C. A.*; Saiz-Lopez, A.*; Yabushita, Akihiro*; Nakano, Yukio*

ACS Earth and Space Chemistry (Internet), 3(4), p.669 - 679, 2019/04

https://doi.org/10.1021/acsearthspacechem.9b00007

The photooxidation of aqueous iodide ions (I) at sea surface results in the emission of gaseous iodine molecules (I) into the atmosphere. It plays a certain role in the transport of iodine from ocean to the atmosphere in the natural cycle of iodine. In this study, we determined the photooxidation parameters, the molar absorption coefficient (()) and the photooxidative quantum yields (()) of I, in the range of 290-500 nm. Through the investigation of the influence of pH and dissolved oxygen (DO) on (), the subsequent emission rates of I following the photooxidation of I in deionized water solution (pH 5.6, DO 7.8 mg L) and artificial seawater solution (pH 8.0, DO 7.0 mg L) were estimated. A global chemistry-climate model employed herein to assess the I ocean emission on a global scale indicated that the photooxidation of I by solar light can enhance the atmospheric iodine budget by up to 8% over some oceanic regions.

Study of particle behavior for steady-state operation in JT-60U

Kubo, Hirotaka; JT-60 Team

Plasma Science and Technology, 8(1), p.50 - 54, 2006/01

https://doi.org/10.1088/1009-0630/8/1/12

no abstracts in English

Disproportionation decomposition of steam on the aluminosilica electrolyte doped with alkali metal hydroxides, JAERI's nuclear research promotion program, H13-015 (Contract research)

Nagase, Kenzo*; Morita, Noboru*; Watanabe, Akiyoshi*; Asao, Toyonobu*

JAERI-Tech 2005-052, 99 Pages, 2005/09

JAERI-Tech-2005-052.pdf:5.92MB

no abstracts in English

Spectroscopic study of hydrogen particle behavior in attached and detached divertor plasmas of JT-60U

Kubo, Hirotaka; Takenaga, Hidenobu; Sawada, Keiji*; Nakano, Tomohide; Kobayashi, Shinji*; Higashijima, Satoru; Asakura, Nobuyuki; Shimizu, Katsuhiro

Journal of Nuclear Materials, 337-339, p.161 - 165, 2005/03

https://doi.org/10.1016/j.jnucmat.2004.09.039

no abstracts in English

Neutron crystallographic study on rubredoxin from by BIX-3, a single-crystal diffractometer for biomacromolecules

Kurihara, Kazuo; Tanaka, Ichiro*; Chatake, Toshiyuki*; Adams, M. W. W.*; Jenney, F. E. Jr.*; Moiseeva, N.*; Bau, R.*; Niimura, Nobuo

Proceedings of the National Academy of Sciences of the United States of America, 101(31), p.11215 - 11220, 2004/08

https://doi.org/10.1073/pnas.0403807101

The structure of a rubredoxin (Rd) from , an organism that grows optimally at 100 C, was determined using the neutron single-crystal diffractometer for biological macromolecules (BIX-3) at the JRR-3 reactor of JAERI. Data were collected at room temperature up to a resolution of 1.5 , and the completeness of the data set was 81.9 %. The model contains 306 H atoms and 50 D atoms. A total of 37 hydration water molecules were identified. The model has been refined to final agreement factors of = 18.6 % and = 21.7 %. Several orientations of the O-D bonds of side chains, whose assignments from X-ray data were previously ambiguous, were clearly visible in the neutron structure. While most backbone N-H bonds had undergone some degree of H/D exchange throughout the molecule, five H atom positions still had distinctly negative (H) peaks. The neutron Fourier maps clearly showed the details of an extensive set of H bonds involving the ND terminus that may contribute to the unusual thermostability of this molecule.

Initial oxidation of Ti(0001) surfaces induced by supersonic oxygen molecular beams

Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Mizuno, Yoshiyuki*; Tonda, Hideki*; Homma, Teiichi*; Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke; Hachiue, Shunsuke

JAERI-Tech 2004-046, 25 Pages, 2004/06

JAERI-Tech-2004-046.pdf:2.51MB

We investigated the correlation between initial sticking coefficient and O transitional kinetic energy to understand O adsorption processes on the Ti(0001) surface via photoemission spectroscopy for O-1s and Ti-2p core levels using the surface reaction analysis apparatus, installed at the JAERI soft X-ray beamline BL23SU in the SPring-8. We observed the decrease of initial sticking coefficient of O molecules on the Ti(0001) surface with increasing O transitional kinetic energy. We concluded that the O adsorption on the Ti(0001) surface proceeded by a trapping-mediated dissociative adsorption mechanism. The constant dependence of the initial sticking coefficient on incident angle of O beams also suggested the propriety of the trapping-mediated surface reaction mechanism.

Hydrocarbons in divertor plasmas; What can be understood from spectroscopy

Nakano, Tomohide; Kado, Shinichiro*

Purazuma, Kaku Yugo Gakkai-Shi, 80(2), p.91 - 100, 2004/02

http://ci.nii.ac.jp/naid/110003827674

Descriptions on the band structure of the system of a CH radical, the method of hydrocarbon flux measurement and the modeling of hydrocarbon elementary processes are given. Then, the reviews of recent research achievements are presented. At JT-60U divertor plates, the chemical sputtering yields of not only but also have been measured with simultaneous measurement of CH and bands. In MAP-II of the University of Tokyo, hydrocarbon-enhanced molecular assisted recombination processes have been qualitatively proved by comparison of the measured and the modeled CH band intensity.

X-ray-induced ion desorption from solid surfaces

Baba, Yuji

Trends in Vacuum Science & Technology, Vol.5, p.45 - 74, 2002/10

This article reviews recent works on the ion desorption from solid surfaces induced by the irradiation of soft X-rays ranging from 100 eV to 3 keV. The data presented here are focused on the positive ion desorption from adsorbed, condensed, and solid molecules following the core-level excitations. The element-specific and site-specific fragment-ion desorptions are clearly realized, when we tune the photon energy at the core-to-valence resonance regions. The specificity of the ion desorption more clearly shows up following the deep-core excitations, i.e., 1s4p resonant excitations in third-row elements, rather than the shallow-core excitations. Since the main decay channels after the core-level excitation are the Auger transitions, the Auger decay spectra excited by the photons around the core-level thresholds are also presented for some of the adsorbed systems. The mechanism of the observed highly specific ion desorption is discussed on the basis of the photon-energy dependencies of the electron and ion yields and the analysis of the Auger decay spectra.

O reaction dynamics with Si(001) surfaces as observed by synchrotron radiation photoemission spectroscopy

Teraoka, Yuden; Yoshigoe, Akitaka

Atomic Collision Research in Japan, No.28, p.97 - 99, 2002/00

The translational kinetic energy of incident molecules is an important factor for the induction of surface reactions. We applied supersonic seed molecular beam techniques and high-energy-resolution photoemission spectroscopy using synchrotron radiation to the Si initial oxidation analysis. We have already found out that the saturated oxygen coverage on HO-chemisorbed Si(001) surfaces depends on the O incident energy. Two potential energy barriers were confirmed in accordance with the first-principles calculation. An action of the incident energy should be confirmed also on clean Si(001) surfaces. Therefore, the incident energy dependence of the O dissociative chemisorption on the clean Si(001) surface has been investigated by photoemission spectroscopy for Si-2p and O-1s core levels to make clear how the incident energy affects the ultra-thin oxide-layers formation.