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排序方式: 共有1294条查询结果,搜索用时 15 毫秒
31.
Hitoshi Muta 《Journal of Nuclear Science and Technology》2019,56(5):367-368
Recent activities in the field of Nuclear Operational Management and Nuclear Safety Engineering, the studies related to risk analysis methodology, design, and operational management, physical phenomena, and emergency preparedness and nuclear security, have been progressed. Especially, ‘risk analysis methodology’ and ‘design and operational management’ are the main categories of the field, in which more than half of published articles on Journal of Nuclear Science and Technology are related to these categories. 相似文献
32.
Akio Ohta Faisal Hossain Hitoshi Asakawa Tsuyoshi Asakawa 《Journal of surfactants and detergents》2020,23(1):99-108
Cysteine and methionine, two sulfur-containing amino acids (AA), were introduced in their surfactant forms as potential antioxidants. The antioxidative (AOX) properties of lauroyl methionine (C12-Met) and lauroyl cysteine (C12-Cys) was investigated by means of the oxygen radical absorbance capacity assay. Both the surfactants exhibited excellent AOX behavior at the premicellar state and micellar medium. The AOX behavior was found to be comparable for both the surfactants at their premicellar states. However, in micellar medium, C12-Met showed better AOX property than C12-Cys. The AOX power of the surfactants was compared with other previously developed AA-type surfactants. The order of the AOX power was found to be: C12-tryptophan > C12-tyrosine ≈ C12-methionine ≈ C12-cysteine > C12-histidine at the premicellar state and C12-tryptophan > C12-tyrosine > C12-methionine > C12-cysteine > C12-histidine at the micellar state. C12-Cys displayed lower AOX property in micellar medium due to its dimer formation tendency. Based on the HPLC and UPLC-Q-TOF-MS analysis, the dimer formation of C12-Cys was found to be accelerated due to the micellar environment and results into negative synergistic effect on other aromatic AA-type surfactants. However, the presence of C12-His in the micellar solution of C12-Cys resulted no synergistic effect due to stronger H-bonding between the surfactants and resulting less dimer formation. 相似文献
33.
Hitoshi Tonomura Masateru Nagae Ryota Takatori Hidenobu Ishibashi Tomonori Itsuji Kenji Takahashi 《International journal of molecular sciences》2020,21(22)
This paper aims to provide a comprehensive review of the changing role of hepatocyte growth factor (HGF) signaling in the healthy and diseased synovial joint and spine. HGF is a multifunctional growth factor that, like its specific receptor c-Met, is widely expressed in several bone and joint tissues. HGF has profound effects on cell survival and proliferation, matrix metabolism, inflammatory response, and neurotrophic action. HGF plays an important role in normal bone and cartilage turnover. Changes in HGF/c-Met have also been linked to pathophysiological changes in degenerative joint diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IDD). A therapeutic role of HGF has been proposed in the regeneration of osteoarticular tissues. HGF also influences bone remodeling and peripheral nerve activity. Studies aimed at elucidating the changing role of HGF/c-Met signaling in OA and IDD at different pathophysiological stages, and their specific molecular mechanisms are needed. Such studies will contribute to safe and effective HGF/c-Met signaling-based treatments for OA and IDD. 相似文献
34.
Yoshinori Iwahashi Zenji Horita Minoru Nemoto Terence G. Langdon 《Metallurgical and Materials Transactions A》1998,29(10):2503-2510
Experiments were undertaken to compare the equal-channel angular (ECA) pressing of Al-1 pct Mg and Al-3 pct Mg solid-solution
alloys with pure Al. The results reveal both similarities and differences between these three materials. Bands of subgrains
are formed in all three materials in a single passage through the die, and these subgrains subsequently evolve, on further
pressings through the die, into an array of grains with high-angle boundaries. However, the addition of magnesium to an aluminum
matrix decreases the rate of recovery and this leads, with an increasing Mg content, both to an increase in the number of
pressings required to establish a homogeneous microstructure and to a decrease in the ultimate equiaxed equilibrium grain
size. It is concluded that alloys exhibiting low rates of recovery should be especially attractive candidate materials for
establishing ultrafine structures through grain refinement using the ECA pressing technique. 相似文献
35.
Fukuyama Y Yasuda N Kim J Murayama H Ohshima T Tanaka Y Kimura S Kamioka H Moritomo Y Toriumi K Tanaka H Kato K Ishikawa T Takata M 《The Review of scientific instruments》2008,79(4):045107
An ultra-high-precision clock system for long time delay has been developed for picosecond time-resolved x-ray diffraction measurements using synchrotron radiation (SR) pulses and synchronized femtosecond laser pulses. The time delay control between pump laser pulse and the probe SR pulse was achieved by combining an in-phase quadrature modulator and a synchronous counter. This method allowed us to change the delay time by a nearly infinite amount while maintaining the precision of +/-8.40 ps. Time-resolved diffraction measurements using the delay control system were demonstrated for precise measurement of an acoustic velocity in a single crystal of gallium arsenide. 相似文献
36.
Kawai T Chun WJ Asakura K Koike Y Nomura M Bando KK Ted Oyama S Sumiya H 《The Review of scientific instruments》2008,79(1):014101
The design and performance of a new high-pressure and high-temperature cell for measurement of x-ray absorption fine structure (XAFS) spectra of solid catalysts working in a flowing liquid are presented. The cell has flat, high-purity sintered cubic boron nitride (c-BN) windows which can tolerate high temperature (900 K) and high pressure (10 MPa). The c-BN is a new material which has the highest tensile strength, second only to diamond, and is also chemically and thermally stable. The use of the cell is demonstrated for measurements of PtPdAl(2)O(3) and Ni(2)PSiO(2) hydrodesulfurization catalysts at reaction conditions. A technique called delta chi (Deltachi), involving determining the difference between XAFS spectra of the sample at reaction conditions and the bare sample, is introduced. 相似文献
37.
Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes 总被引:1,自引:0,他引:1
Tsukizaki R Koizumi H Nishiyama K Kuninaka H 《The Review of scientific instruments》2011,82(12):123103
In order to reveal the physical processes taking place within the "μ10" microwave discharge ion thruster, internal plasma diagnosis is indispensable. However, the ability of metallic probes to access microwave plasmas biased at a high voltage is limited from the standpoints of the disturbance created in the electric field and electrical isolation. In this study, the axial density profiles of excited neutral xenon were successfully measured under ion beam acceleration by using a novel laser absorption spectroscopy system. The target of the measurement was metastable Xe I 5p(5)((2)P(0) (3/2))6s[3/2](0) (2) which absorbed a wavelength of 823.16 nm. Signals from laser absorption spectroscopy that swept a single-mode optical fiber probe along the line of sight were differentiated and converted into axial number densities of the metastable neutral particles in the plasma source. These measurements revealed a 10(18) m(-3) order of metastable neutral particles situated in the waveguide, which caused two different modes during the operation of the μ10 thruster. This paper reports a novel spectroscopic measurement system with axial resolution for microwave plasma sources utilizing optical fiber probes. 相似文献
38.
Yasutoshi Kasahara Masashi Kato Satoshi Watanabe Makio Iwahashi Rieko Wakamatsu Takashi Suzuki Akinori Kanetani Takaaki Kano Takamitsu Tamura 《Journal of the American Oil Chemists' Society》2012,89(7):1223-1229
Mineral oil is commonly used as an electrical insulating oil in transformers because of its relatively high electrical insulating
ability and fluidity. Considering the depletion of resources and environmental problems, however, fatty acid esters synthesized
from natural plant oils are attracting attention as an environmentally friendly insulating oil. In addition, fatty acid esters
such as methyl octanoate, methyl dodecanoate, 2-ethylhexyl octanoate, and 2-ethylhexyl dodecanoate have high fluidity, and
also show excellent moisture tolerance against dielectric breakdown compared to mineral oil. In the present study, to clarify
the reason for the superior moisture tolerance of fatty acid esters, the status of dissolved water in esters is investigated
with IR spectroscopic measurements and density functional theory (DFT) calculations. It is revealed that water molecules in
fatty acid esters are trapped by the ester moiety of fatty acid esters. As a result, fatty acid esters have a higher moisture
tolerance against dielectric breakdown than mineral oil. 相似文献
39.
Hirotoshi Miyazaki Kazutoshi Terada Toshiaki Sato Hitoshi Maruyama Takuji Okaya 《应用聚合物科学杂志》1996,60(12):2149-2157
In dispersion polymerization of styrene in ethanol, effects of a reactive steric stabilizer, poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group (P(VAc/VA)-SH), were investigated. In the absence of the thiol end group, the dispersion coagulated at the middle stage of the polymerization, while in the presence of the thiol end group, the polymerization proceeded successfully to result in close to monodisperse particles. The reactive thiol group acts as a site of formation of the block copolymer, that is, polystyrene-b-P(VAc/VA), which is utilized as an effective dispersant. From the measurement on molecular weights during the course of polymerization, two polymerization loci were realized. Addition of butyl methacrylate to styrene affected markedly not only rate of polymerization but also particle size. © 1996 John Wiley & Sons, Inc. 相似文献
40.
The effect of sodium thiosulfate on the graft copolymerization of methyl methacrylate to cellulose in the hydrogen peroxide initiator system was investigated. The addition of sodium thiosulfate in general was effective for decreasing the per cent grafting and the average molecular weight of grafts and increasing the formation of homopolymer, and the effects became pronounced with increasing hydrogen peroxide concentration. Moreover, the addition of sodium thiosulfate slightly suppressed the formation of grafts at a hydrogen peroxide concentration of 3 mmole/l., but greatly promoted it at 20 mmole/l. Traces of metallic ions present in cellulose could not be eliminated sufficiently by treatment with 3N hydrochloric acid. Such ions were found to interact with hydrogen peroxide and thus participate directly in the initiation and termination of the polymerization reaction. EDTA, the chelating agent, was highly effective for suppressing such participation of metallic ions. In the hydrogen peroxide initiator system applied to the EDTA-treated samples, sodium thiosulfate caused an effective initiation of graft formation. 相似文献