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Journal Articles

Stoichiometry between humate unit molecules and metal ions in supramolecular assembly induced by Cu$$^{2+}$$ and Tb$$^{3+}$$ measured by gel electrophoresis techniques

Nakano, Sumika*; Marumo, Kazuki*; Kazami, Rintaro*; Saito, Takumi*; Haraga, Tomoko; Tasaki-Handa, Yuiko*; Saito, Shingo*

Environmental Science & Technology, 55(22), p.15172 - 15180, 2021/11

 Times Cited Count:4 Percentile:33.24(Engineering, Environmental)

Humic acid (HA) can strongly complex with metal ions to form a supramolecular assembly via coordination binding. However, determining the supramolecular size distribution and stoichiometry between small HA unit molecules constituting HA supramolecule and metal ions has proven to be challenging. Here, we investigated the changes in the size distributions of HAs induced by Cu$$^{2+}$$ and Tb$$^{3+}$$ ions using a unique polyacrylamide gel electrophoresis (PAGE) for the separation and quantification of HA complexes and metal ions bound, followed by UV-Vis spectroscopy and EEM-PARAFAC. It was found that the supramolecular behaviors of Cu$$^{2+}$$ and Tb$$^{3+}$$ complexes with HA collected from peat and deep groundwater (HHA) differed. Our results suggest that this supramolecular stoichiometry is related to the abundance of sulfur atoms in the elemental composition of HHA. Our results provide new insights into HA supramolecules formed via metal complexation.

Journal Articles

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

 Times Cited Count:2 Percentile:26.16(Chemistry, Physical)

Journal Articles

Probing the long-range structure of the $$T^{+}_{cc}$$ with the strong and electromagnetic decays

Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*

Physical Review D, 104(5), p.L051502_1 - L051502_8, 2021/09

 Times Cited Count:46 Percentile:98.62(Astronomy & Astrophysics)

We investigate the kinetically allowed strong and electromagnetic decays of the recently observed $$T^+_{cc}$$. Our results show that the decay width of $$T_{cc}to D^0D^0pi^+$$ is the largest one, which is just the experimental observation channel. Our theoretical total strong and radiative widths are in favor of the $$T_{cc}$$ as a $$D^{*+}D^0$$ dominated bound state. Our calculation is cutoff-independent and without prior isospin assignment. The absolute partial widths and ratios of the different decay channels can be used to test the structure of $$T_{cc}$$ state when the updated experimental results are available.

Journal Articles

Experimental determination of the photooxidation of aqueous I$$^{-}$$ as a source of atmospheric I$$_{2}$$

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

 Times Cited Count:7 Percentile:46.03(Chemistry, Multidisciplinary)

The photooxidation of aqueous iodide ions (I$$^{-}$$$$_{(aq)}$$) at sea surface results in the emission of gaseous iodine molecules (I$$_{2}$$$$_{(g)}$$) 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 ($$varepsilon$$$$_{iodide}$$($$lambda$$)) and the photooxidative quantum yields ($$Phi$$$$_{iodide}$$($$lambda$$)) of I$$^{-}$$$$_{(aq)}$$, in the range of 290-500 nm. Through the investigation of the influence of pH and dissolved oxygen (DO) on $$Phi$$$$_{iodide}$$($$lambda$$), the subsequent emission rates of I$$_{2}$$$$_{(g)}$$ following the photooxidation of I$$^{-}$$$$_{(aq)}$$ in deionized water solution (pH 5.6, DO 7.8 mg L$$^{-1}$$) and artificial seawater solution (pH 8.0, DO 7.0 mg L$$^{-1}$$) were estimated. A global chemistry-climate model employed herein to assess the I$$_{2}$$$$_{(g)}$$ ocean emission on a global scale indicated that the photooxidation of I$$^{-}$$$$_{(aq)}$$ by solar light can enhance the atmospheric iodine budget by up to $$sim$$8% over some oceanic regions.

Journal Articles

Analytic cross sections for electron impact collisions with nitrogen molecules

Tabata, Tatsuo*; Shirai, Toshizo*; Sataka, Masao; Kubo, Hirotaka

Atomic Data and Nuclear Data Tables, 92(3), p.375 - 406, 2006/05

 Times Cited Count:71 Percentile:94.99(Physics, Atomic, Molecular & Chemical)

no abstracts in English

Journal Articles

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

 Times Cited Count:2 Percentile:7.11(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Cross sections of charge transfer by slow doubly-charged carbon ions from various carbon containing molecules

Kusakabe, Toshio*; Shiota, Kenji*; Kubo, Hirotaka; Shirai, Toshizo*

Journal of Plasma and Fusion Research SERIES, Vol.7, p.237 - 239, 2006/00

no abstracts in English

JAEA Reports

Journal Articles

A Severe artifact in simulation of liquid water using a long cut-off length; Appearance of a strange layer structure

Yonetani, Yoshiteru

Chemical Physics Letters, 406(1-3), p.49 - 53, 2005/04

 Times Cited Count:50 Percentile:84.11(Chemistry, Physical)

We report that a severe artifact appeared in molecular dynamics simulation of bulk water using the long cut-off length 18 AA ; Our result shows that increasing the cut-off length does not always improve the simulation result. Moreover, the use of the long cut-off length can lead to a spurious result. It is suggested that the simulation of solvated biomolecules using such a long cut-off length, which has been often performed, may contain an unexpected artifact.

Journal Articles

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

 Times Cited Count:15 Percentile:70.18(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Divertor spectroscopy with molecular transport

Kubo, Hirotaka; Takenaga, Hidenobu; Nakano, Tomohide; Higashijima, Satoru; Shimizu, Katsuhiro; Sawada, Keiji*; Kobayashi, Shinji*; JT-60 Team

Nuclear Fusion Research; Springer Series in Chemical Physics, Vol.78, p.121 - 134, 2004/11

no abstracts in English

Journal Articles

Neutron crystallographic study on rubredoxin from ${it Pyrococcus furiosus}$ 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

 Times Cited Count:48 Percentile:61.44(Multidisciplinary Sciences)

The structure of a rubredoxin (Rd) from ${it Pyrococcus furiosus}$, an organism that grows optimally at 100 $$^{circ}$$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 ${AA}$, 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 ${it R}$ = 18.6 % and ${it R}$$$_{free}$$ = 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$$_{3}$$$$^{+}$$ terminus that may contribute to the unusual thermostability of this molecule.

Journal Articles

Analysis of surface chemical reaction dynamics by using high brilliance and high energy-resolution synchrotron radiation

Teraoka, Yuden

Denki Gakkai Gijutsu Hokoku, (970), p.10 - 15, 2004/07

Si(001) surfaces are oxidized by O$$_{2}$$ molecules. The reaction schemes (oxide-layers formation, SiO desorption, their coexistence) are changed depending on the surface temperature and the gas pressure. The translational kinetic energy of incident O$$_{2}$$ molecules is recognizing to be an important parameter for controlling surface chemical reactions. The issues concerning translational kinetic energy induced oxidation by O$$_{2}$$ molecules at room temperature, effects of translational kinetic energy for SiO desorption processes at higher temperature than 1000 K, reaction mechanisms for coexistence of the SiO desorption and the oxide-layers formation in the temperature region from 900 K to 1000 K are reviewed.

JAEA Reports

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$$_{2}$$ transitional kinetic energy to understand O$$_{2}$$ 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$$_{2}$$ molecules on the Ti(0001) surface with increasing O$$_{2}$$ transitional kinetic energy. We concluded that the O$$_{2}$$ 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$$_{2}$$ beams also suggested the propriety of the trapping-mediated surface reaction mechanism.

Journal Articles

Chemical reaction dynamics in oxidation processes of Si(001) surface at high temperature

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke

Shinku, 47(4), p.301 - 307, 2004/04

Recent research results on translational kinetic energy effects of incident oxygen molecules for Si(001) oxidation are summalized and introduced. The variation of surface temperature dependence of SiO desorption yield, oxygen uptake curves, and chemical bonding states depending on translational kinetic energy of oxygen molecules is described concretely. Eapecially, the translational kinetic energy effects on chemical reaction processes of concurrent oxide-layers formation and SiO desorption are discussed.

Journal Articles

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

Descriptions on the band structure of the $$A^2{it Delta}to X^2{it Pi}$$ 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 $$mbox{CH}_4$$ but also $$mbox{C}_2mbox{H}_x$$ have been measured with simultaneous measurement of CH and $$mbox{C}_2$$ 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.

Journal Articles

Element-specific and site-specific ion desorption from adsorbed molecules by deep core-level photoexcitation at the $$K$$-edges

Baba, Yuji

Low Temperature Physics, 29(3), p.228 - 242, 2003/03

 Times Cited Count:53 Percentile:52.06(Physics, Applied)

no abstracts in English

Journal Articles

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., 1s$$rightarrow$$4p 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.

Journal Articles

Atomic and molecular processes for heat and particle control in tokamaks

Kubo, Hirotaka

AIP Conference Proceedings 636, p.161 - 170, 2002/00

no abstracts in English

Journal Articles

O$$_{2}$$ 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 H$${_2}$$O-chemisorbed Si(001) surfaces depends on the O$${_2}$$ 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$${_2}$$ 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.

55 (Records 1-20 displayed on this page)