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571.
This article illustrates how bifunctional catalyst surfaces are created by modifying oxide surfaces with organic functional groups and/or with metal complexes, summarizing our previous reports and also presenting new data, which provide a new class of catalytic materials with a high complexity for selective catalysis including C–C coupling, hydroformylation, and asymmetric reactions. The catalyst surfaces are characterized by in situ physical analysis techniques such as time-resolved XAFS, FT-IR, solid-state MAS NMR and so on. 相似文献
572.
Chika Ohira Hidetoshi Fujii Yoshiaki Morisada 《Journal of Materials Engineering and Performance》2014,23(5):1561-1567
The surface tension of molten Sn-Ag alloys was measured using a specially developed high-accuracy sessile drop apparatus. In this apparatus, a molten sample is dropped onto a R-Al2O3 substrate in order to prevent any reaction between the sample and substrate during the heating process. The droplet shape was recorded from two perpendicular directions to confirm its symmetry. The oxygen partial pressure ( $ {P_{{{\text{O}}_2}}} $ ) was controlled by a Mg furnace to a value of about 10?16 to 10?15 Pa. The sample compositions used were Sn-20Ag, Sn-50Ag, and Sn-80Ag (at.%) and were alloyed from pure Sn (99.999%) and Ag (99.99%) in the dropping tube. The accuracy of the experimental results was confirmed by an extremely small scatter. The measured temperature dependence of the surface tension of the molten Sn-50Ag (at.%) alloy indicated a characteristic curve that changed from positive to negative with increasing temperature. Furthermore, the surface tension of the molten Sn-20Ag (at.%) alloy has a temperature dependence that changes from flat to negative, while the Sn-80Ag (at.%) alloy has a negative temperature dependence across the whole temperature range. Based on a theoretical discussion using Butler’s equation, these temperature dependencies can be determined by negative straight lines when assuming the surface composition. 相似文献
573.
Catechins [(−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG)] were analysed by HPLC using an ODS column, an electrochemical detector (0.75 V vs. Ag/AgCl) and an eluting solvent composed of water containing buffer (84% v/v), acetonitrile (12% v/v) and ethylacetate (4% v/v) in the presence of metal ions (Cu2+, Fe2+ and Fe3+). HPLC peaks were affected by metal ions: the peak intensities of ECG and EGCG decreased, but the peak intensities of EC and EGC were not affected seriously. Fe2+ most markedly decreased the peak intensities of EGCG. EDTA was added to mask metal ions and an optimum condition was proposed. The effects of the metal ions on HPLC analysis are discussed from the viewpoints of metal complex formation with catechins and oxidation of catechins on the basis of ultraviolet–visible (UV–vis) spectrophotometry, electrospray ionisation mass spectrometry (ESI-MS) and cyclic voltammetry (CV). 相似文献
574.
Tatsuya Sakamoto Tsutomu Iida Yasuhiko Honda Mitsuhiro Tada Takeshi Sekiguchi Keishi Nishio Yasuo Kogo Yoshihumi Takanashi 《Journal of Electronic Materials》2012,41(6):1805-1810
The electrical and thermoelectric characteristics of n-type Mg2Si equipped with electrodes of Ni and the transition-metal silicides CoSi2, CrSi2, TiSi2, and NiSi were examined. To form the electrodes on the Mg2Si matrix, a monobloc sintering method, i.e., simultaneous sintering of the electrode material during Mg2Si sintering, was used. To obtain dense electrodes and to keep an appropriately low sintering temperature for the Mg2Si matrix, a Ni binder was used for the CoSi2, CrSi2, and TiSi2 monobloc sintering. The mixture ratio between the transition-metal silicide and the Ni was 50:50 in wt.%. The room-temperature I?CV characteristics of the fabricated CoSi2, CrSi2, and TiSi2 electrodes with the Ni binder and NiSi electrodes were considered to be adequate for practical applications in as much as ohmic contacts were obtained. The contact resistance at the Mg2Si/electrode interface decreased by 35% and 28%, respectively, for the CoSi2 and CrSi2 electrodes compared with our standard Ni electrode. The thermoelectric power output was measured at the practical operating temperature of 600?K, with ??T?=?500?K. The observed output powers for 3.0?mm?×?3.0?mm?×?7.5?mm samples equipped with CoSi2, CrSi2, and NiSi electrodes were 153?mW, 149?mW, and 125?mW, respectively, representing increases of 27%, 24%, and 4%, respectively, compared with the 120?mW measured for the sample with Ni electrodes. 相似文献
575.
Yoshimori Kento Okuda Chika Ohta Shinji Ômura Hisashi 《Journal of chemical ecology》2022,48(5-6):518-530
Journal of Chemical Ecology - The common grass yellow Eurema mandarina has a characteristic patch (sex brand) composed of specialized scales (androconia) and wing intermembranous cells on the... 相似文献
576.