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91.
Hisayuki Suematsu Mamoru Mitomo Terence E. Mitchell John J. Petrovic Osamu Fukunaga Naoki Ohashi 《Journal of the American Ceramic Society》1997,80(3):615-620
Single crystals of α-Si3 N4 were annealed at 2000°–2150°C. The β phase was detected after annealing at 2150°C only when the crystals were surrounded by MgO·3Al2 O3 or Y2 O3 powders. On the other hand, no evidence of the α–β transformation was found when the crystals were annealed without additives. The solution–precipitation mechanism was concluded to be the dominant factor in the α–β transformation of Si3 N4 . 相似文献
92.
Phase Relations and Volume Changes of Hafnia under High Pressure and High Temperature 总被引:1,自引:0,他引:1
Osamu Ohtaka Hiroshi Fukui Taichi Kunisada Tomoyuki Fujisawa Kenichi Funakoshi Wataru Utsumi Tetsuo Irifune Koji Kuroda Takumi Kikegawa 《Journal of the American Ceramic Society》2001,84(6):1369-1373
Using multi-anvil high-pressure devices and synchrotron radiation, X-ray in situ observations of HfO2 under high pressure and high temperature have been performed to investigate its phase relations and compression behavior. An orthorhombic phase (orthoI) is stable from 4 to 14.5 GPa below 1250°–1400°C and transforms to a tetragonal phase, which is one of the high-temperature forms of HfO2 , above these temperatures. Another orthorhombic phase (orthoII) with a cotunnite-type structure appears above 14.5 GPa. OrthoII is stable up to 1800°C at 21 GPa. OrthoII is quenchable to ambient conditions. The orthoI-to-orthoII transition is accompanied by ∼8 vol% decrease. The bulk moduli of orthoI and orthoII at room temperature are 220 and 312 GPa, respectively. This low compressibility of orthoII indicates that it is a potential candidate for very hard materials. 相似文献
93.
Meso-porous Al2O3-supported Ni catalysts exhibited the highest activity, stability and excellent coke-resistance ability for CH4 reforming with CO2 among several oxide-supported Ni catalysts (meso-porous Al2O3 (Yas1-2, Yas3-8), -Al2O3, -Al2O3, SiO2, MgO, La2O3, CeO2 and ZrO2). The properties of deposited carbons depended on the properties of the supports, and on the meso-porous Al2O3-supported Ni catalyst, only the intermediate carbon of the reforming reaction formed. XRD and H2-TPR analysis found that mainly spinel NiAl2O4 formed in meso-porous Al2O3 and -Al2O3-supported catalysts, while only NiO was detected in -Al2O3, SiO2, CeO2, La2O3 and ZrO2 supports. The strong interaction between Ni and meso-porous Al2O3 improved the dispersion of Ni, retarded its sintering and improved the activated adsorption of CO2. The coking reaction via CH4 temperature-programed decomposition indicated that meso-porous Al2O3-supported Ni catalysts were less active for carbon formation by CH4 decomposition than Ni/-Al2O3 and Ni/-Al2O3. 相似文献
94.
Keiji Mimura Susumu Yukawa Yoshio Mori Kazuya Okada Masatoshi Mune Osamu Nishikawa Akira Hibino Miyahiko Sonobe Tetuya Goto Hiroshi Nomoto 《Lipids》1991,26(12):1102-1107
We investigated the effect of platelet-activating factor (PAF) and of the PAF specific antagonist CV-6209 on plasma lipid
metabolism, and particularly on post-heparin plasma lipolytic activity in male Wistar rats. Lipoprotein lipase (LPL) activity
was enhanced by intravenous injection of PAF before intravenous injection of heparin when the PAF dose was low (0.2 μg/kg).
PAF activated hepatic triacylglycerol lipase (HTGL) activity dose-dependently. Plasma triacylglycerols (TG) significantly
decreased with the activation of LPL and/or HTGL. Plasma total cholesterol (TC) and phospholipid (PL) levels decreased at
a low dose of PAF (0.2 μg/kg), but increased when higher doses were used. The PAF antagonist CV-6209 partially reversed the
PAF induced effects on HTGL, TC and PL.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
95.
Various copolymides were prepared from two acid dianhydrides (BPDA, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride; PMDA, pyromelitic dianhydride) and two diamines (PPD, p-phenylene diamine; ODA, 4,4′-oxydianiline). The thermal and mechanical properties of these polyimides were examined in detail. By appropriately selecting the ratios of the acid dianhydride component and the diamine component, polyimide films having desirable mechanical and thermal characteristics can be obtained. Further, it was proved that there is a correlation between the properties and the compositions of the copolyimides and that the properties could be estimated from the compositions by the use of multiple regression analysis. © 1996 John Wiley & Sons, Inc. 相似文献
96.
A switched reluctance (SR) motor has a doubly salient pole structure. The performance of the SR motor strongly depends on the magnetic properties of the core material, since it consists only of an iron core and copper windings. This study experimentally evaluates the performance of an SR motor made of permendur (Fe–49% Co alloy), which has very high saturation flux density and low core loss. Two types of SR motors that have the same dimensions but different core materials are used: one motor is made of the conventional nonoriented Si steel, and the other is made of permendur. Comparison of the characteristics of the two motors shows that the performance of the permendur SR motor surpasses that of the conventional one in terms of output power and efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(1): 51–57, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22431 相似文献
97.
Maksudul M. Alam Osamu Ito Naoki Sakurar Hiroshi Moriyama 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(6):1007-1024
Abstract Efficient electron-transfer reactions from three kind of tetraselenafulvalenes (TSeF's) to photoexcited triplet state of C60 or C70 in polar solvents have been confirmed by transient absorption spectroscopy observing the decay of 3C60*/3C70* and rise of C60 ??/C70 ??. Growth of single crystal seems to be stimulated by laser irradiation of the solution containing C60 and bis(ethylenedithio)tetraselena-fulvalene (BEDT-TSeF), in which C60 ?? was effectively formed. 相似文献
98.
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