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991.
XIA ShaoJun CHEN LinGen & SUN FengRui Postgraduate School Naval University of Engineering Wuhan China 《中国科学:化学》2010,(5)
An isothermal endoreversible chemical engine operating between the finite potential capacity high-chemical-potential reservoir and the infinite potential capacity low-chemical-potential reservoir has been studied in this work.Optimal control theory was applied to determine the optimal cycle configurations corresponding to the maximum work output per cycle for the fixed total cycle time and a universal mass transfer law.Analyses of special examples showed that the optimal cycle configuration with the mass tr... 相似文献
992.
Wu Jiong XIA De Run LI Yong Qiang TU* Ao Cheng CAO Department of Chemistry National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing 《中国化学快报》2001,(1)
11,12-dioxygenated eudesmanolide sesquiterpenoid is a large kind of naturally occuring sesquiterpenoids isolated from the medicinal plants, such as J. glutinosa1 and Flourensia heterolepsis 2. In constrast to much investigation of their isolation and structure characterization, the less about their synthesis have been reported. One of the reason may be the difficult hydroxylation at C-11. For example, the synthesis of a simple natural product, kudtriol3, required thirteen steps of reactions f… 相似文献
993.
LOU JianFang WANG RongMin CAI YongFu WANG YunPu SONG PengFei ZHANG ZhenLin XIA Chungu 《高等学校化学研究》2001,17(3)
The epoxide is a kind of versatile intermediate for manufacture of a wide variety of fine chemicals. The goal of modem efficient catalytic methods is to produce desired compounds with high yield, selectivity, low cost, safety, operational simplicity and more importantly environmentally benign manner. However, there are various oxidants, which are often hazardous or expensive, being used for both laboratory and industrial epoxidation. Hydrogen peroxide (30 wt%) solution is thought as one of the ideal oxidants because water is a sole theoretical side product. Meanwhile the epoxidation of styrene is a typical one among olefins. Here, the performance of styrene epoxidation was studied with hydrogen peroxide solution catalyzed by Co(Ⅱ) phenanthroline complex encapsulated in supercages of MCM-41. 相似文献
994.
在回旋加速器中,高频系统为带电粒子加速提供能量,高频谐振腔作为高频系统中的关键部件,它性能的好坏直接决定着粒子是否能够被加速,所以,高频谐振腔的设计非常关键.在100MeV负氢回旋加速器的设计中,在空间限制的同时,要求加速电压从中心区的60kV到出引区的120kV变化,这对谐振腔的设计提出了很高的要求.基于上述条件,本工作利用有限差分法的软件CST MICR0wAVESTUDIO设计的双内杆结构的44MHz高频谐振腔初步设计完成,根据初步设计的结论,加工与实际腔体尺寸1:1模型,模型高频参数测量的结果与CST MICROWAVE STuDIO的计算相吻合,结果是可信的. 相似文献
995.
996.
随着国民经济的增长以及教育成本的提高,大学学费也相应逐年提高.但是我国还存在相当数量的贫困生.助学贷款是解决贫困生完成学业的重要途径.论文站在助学贷款被助者的立场上,将被助者获得的经济效益进行了具体的定量化分析.首先分别讨论了两期不考虑银行利息率和考虑银行利息率情况下,基于CES型效用函数的助学贷款被助者经济效益的计算模型,然后分析了如何计算多期银行利息率情况下贷款被助者的经济效益.最后针对被助群体进行实证分析、计算并得出结论. 相似文献
997.
An RF system for the CSRe (cooling storage experimental ring) is designed and manufactured domestically. The present paper mainly describes the RF system design in five main sections:ferrite ring, RF cavity, RF generator, low level system and cavity cooling. The cavity is based on a type of coaxial resonator which is shorted at the end with one gap and loaded with domestic ferrite rings. The RF generator is designed in the push-pull mode and the low level control system is based on a DSP+FGPA+DDS+USB interface and has three feedback loops. Finally we give the results of the measurement on our system. 相似文献
998.
999.
1000.
Some properties of a class of quasi-differentiable functions(the difference of two finite convex functions) are considered in this paper. And the convergence of the steepest descent algorithm for unconstrained and constrained quasi-differentiable programming is proved. 相似文献