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51.
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Takahiro Gunji Ryosuke Shimano Koji Arimitsu Yoshimoto Abe 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2542-2550
Tetraethoxysilane (TEOS) and polyethoxysiloxanes (PEOSs; prepared by the acid‐catalyzed hydrolytic polycondensation of TEOS) were subjected to the sol–gel process in the presence of cetyltrimethylammonium bromide (CTAB), respectively. The PEOSs with Mw 700–26,000, as prepared by sol–gel coating of TEOS and PEOS under various conditions, were used. Uniform and crack‐free thin films of thickness 276–613 nm were prepared by spin‐coating of a PEOS solution containing CTAB. When the coating films were sintered at 400 °C, the combustion of ethoxy groups and CTAB took place to provide porous silica thin films. The structure of the thin films was found to be dependent on the molecular weight of PEOS and the molar ratio of CTAB/Si: lamellar or hexagonal phase was observed for Mw less than 15,000 and for CTAB/Si molar ratios greater than 0.10. Honeycomb structures were observed for Mw less than 5000 and for CTAB/Si molar ratios of 0.15. The honeycomb structure was also observed by atomic force microscopy and transmission electron microscope. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2542–2550, 2006 相似文献
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We give a self‐contained proof of the preservation theorem for proper countable support iterations known as “tools‐preservation”, “Case A” or “first preservation theorem” in the literature. We do not assume that the forcings add reals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
55.
ShiYanYANG ZeMinXIE ChunJuanLIU LiHuaLIU WeiGAO 《中国化学快报》2002,13(12):1225-1226
A new kind of polyorganozircosilazane as Si/Zr/C/N-based ceramic precursor was synthesized from the condensation reaction of hexamethyleyclotrisilazane lithium salts(D3^NLi)and zirconium tetrachloride(ZrCl4).In the presence of N,N,N’,N’-tetramethyl ethylene diamine(TMEDA),polyorganozircosilazane was obtained in high yield. 相似文献
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采用固相反应法合成A缺位的(La0.8Sr0.2)0.95MnO3(LSM95)作为阴极材料,Zr0.9Sc0.1SO1.95(SSZ)商业粉体作为电解质材料,溶胶-凝胶法合成的La0.8Sr0.2Cr0.5Mn0.5O3-(LSCrM)作为阳极电催化材料,利用流延、共烧结及浸渍法得到结构为LSCrM-CeO2|SSZ|3YSZ-LSM95的阴极支撑型固体氧化物燃料电池,分别在氢气气氛和甲烷气氛中进行电化学性能测试. 结果表明,浸渍0.11 g·cm -2 CeO2的LSCrM-CeO2|SSZ|3YSZ-LSM95单电池在以CH4为燃料时,600、650、700、750和800 oC下的功率密度分别为1.68、4.70、12.40、28.08和54.78 mW·cm -2,表现出一定的电化学性能和较好的稳定性. 相似文献
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Nickel oxide promoted catalysts are prepared by simple precipitation, precipitation from homogeneous solution and impregnation methods and their reduction behavior is monitored with temperature programmed reduction (TPR) technique. The effect of different parameters such as metal loading, method of preparation and heat treatment temperature are also observed on the reducibility of the catalysts. It is observed that reduction temperature increases with the increase of calcination temperature. Results indicate that the interactions between nickel oxide and silica begin with the increase of calcination temperature which leads to the formation of nickel hydrosilicates and are responsible for high temperature reduction peaks. 相似文献
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Complete Oxidation of Methane over Palladium Supported on Alumina Modified with Calcium,Lanthanum,and Cerium Ions 下载免费PDF全文
The activity and thermal stability of Pd/Al_2O_3 and Pd/(Al_2O_3 MO_x)(M=Ca,La,Ce) palladium catalysts in the reaction of complete oxidation of methane are presented in this study.The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide.Then they were impregnated with palladium nitrate solution.The catalysts with unmodified alumina had a high surface area.The activity and thermal stability of the alumina- supported catalyst was also very high.The introduction of calcium,lanthanum,or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method.These modifiers decreased the activity of palladium catalysts,and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al_2O_3.The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction. 相似文献
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The thickness and the porosity of a deposit during ultrafiltration experiments are determined using an electrochemical method. Twenty microelectrodes are mounted flush to a ceramic plane membrane and maps of deposit thickness are determined for three inlet/outlet distributors configurations. Combining an electrochemical method and a step transient method, the determination of the thickness and the porosity of a particles deposit is performed. These local thickness and porosity values are analyzed thanks to wall shear stress local measurements obtained in a previous work [Sep. Sci. Technol. 37 (10) (2002) 2251]. The results emphasize the heterogeneity of the deposit thickness, especially in zones of low wall shear stress. Furthermore, the porosity values of the deposit are ranged between 0.3 and 0.8 as a function of the location at the membrane surface. 相似文献