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91.
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93.
A. Stein 《Advanced materials (Deerfield Beach, Fla.)》2003,15(10):763-775
This report highlights developments in the fields of microporous and mesoporous materials that were published mostly during the year 2002. Selected examples are provided to illustrate new zeolite structures, porous coordination materials, mesoporous solids with new compositions, controlled morphologies, and increased hydrothermal and thermal stabilities, as well as porous solids with tunable pore openings or other structural features that can be dynamically modified. A number of applications are discussed, including stabilization of reactive guests, separations, electronic materials, and sensors. 相似文献
94.
城市二次加压供水设施污染的防治与对策 总被引:2,自引:2,他引:0
从设计、施工、管理等方面,分析了城市二次加压设施污染的原因,提出设计及施工中的防治对策及二次加压设施管理上的对策,以确保城市安全供水。 相似文献
95.
周龙标 《上海电机学院学报》2003,6(2):58-62
改革开放使中国经济实现了持续高速的发展。然而,随着改革的不断深入,国有资产面临着在新经济环境下的角色转换,在此过程中由于各种原因每年有数百亿元的国有资产流失,所以,国有资产的保值增值成为现阶段乃至将来一段时间我国政府的重大经济课题。本文对国有资产的历史和现状进行了分析并从多角度提出了一些管理方面的看法。 相似文献
96.
《Drying Technology》2007,25(7):1175-1183
Although considerable progress has been made in the development of experimental techniques for investigating velocity distribution inside a fixed bed, these techniques were limited to special cases. Consequently, the velocity distribution is normally measured at downstream of the fixed bed and then this measurement is considered to be representative for the flow inside the bed. To evaluate the representativeness of this technique, this work presents a study of the change in the flow characteristics, starting from the boundary of the fixed bed within the pipe to a downstream position where the experimental measurement is taken, by using simulations based on computational fluid dynamics methods. 相似文献
97.
Titipong Issariyakul Mangesh G. KulkarniAjay K. Dalai Narendra N. Bakhshi 《Fuel Processing Technology》2007
Transesterification of waste fryer grease (WFG) containing 5–6 wt.% free fatty acid (FFA) was carried out with methanol, ethanol, and mixtures of methanol/ethanol maintaining the oil to alcohol molar ratio of 1:6, and initially with KOH as a catalyst. Mixtures of methanol and ethanol were used for transesterification in order to use the better solvent property of ethanol and rapid equilibrium using methanol. Formation of soap by reaction of FFA present in WFG with KOH instigated difficulty in the separation of glycerol from biodiesel ester. To untangle this problem, two-stage (acid and alkali catalyzed) method was used for biodiesel synthesis. More than 90% ester was obtained when two-stage method was used compared to ∼ 50% ester in single stage alkaline catalyst. In the case of mixed alcohol, a relatively smaller amount of ethyl esters was formed along with methyl esters. Acid value, viscosity, and cetane number of all the esters prepared from WFG were within the range of the ASTM standard. Esters obtained from WFG showed good performance as a lubricity additive. 相似文献
98.
99.
N. F. Kuschevskaya A. E. Kushchevskii A. I. Oleshko 《Powder Metallurgy and Metal Ceramics》2006,45(3-4):202-206
The possibility of utilizing nanopowders of iron and Fe-Co-Ni produced bu a thermochemical method in the fabrication of sealing
composition materials is investigated. It is established that such hermetic sealing composition materials function reliably
under extremal conditions and guarantee elevated strength of adhesion to the surface of the metal and high corrosion and temperature
stability.
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Translated from Poroshkaya Metallurgiya, Nos. 3–4(448), pp. 112–117, March–April, 2006. 相似文献
100.