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排序方式: 共有627条查询结果,搜索用时 15 毫秒
511.
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研究了一维晶格中费曼棘齿-棘爪热机模型. 用粒子的概率主方程来描述粒子在晶格中的动力学特性, 推导出热流、 功率和效率的表达式. 通过数值计算分析势垒高度、 外力和温比对热流以及热机功率和效率的影响. 研究表明: 在粒子稳态概率流为零时, 存在非零的热流从高温库流入低温库, 类似于经典不可逆卡诺模型中的热漏; 热漏的存在使得热机的效率远远小于卡诺效率, 功率与效率之间为闭合的关系曲线, 热机为不可逆热机; 对热机性能参数进行优化, 可以使热机工作在最优性能状态下. 相似文献
513.
Liang SHEN De Zhan CHEN* College of Chemistry Chemical Engineering Materials Science Shandong Normal University Jinan 《中国化学快报》2004,15(11)
In the past two decades, perylenequinonoid derivatives (PQD), such as hypocrellin A (HA), hypocrellin B (HB) and hypericin (HYP) have attracted considerable attention owing to their excellent properties of photosensitization and great advantages over the investigation of intramolecular proton transfer (IPT)1-5. Previous researches demonstrated that IPT both in the ground state and excited states exists in PQD and is critical for PQD to reserve their photosensitive activity3,6. Altho… 相似文献
514.
Ying Jie SUN Jian Ya LING Peng L Han Xing ZHANG Chang Kai ZHANG* State Key Laboratory of Microbial Technology Life Science School of Shandong University Jinan 《中国化学快报》2003,14(7)
~~Determination of Cordycepin in Cordyceps kyushuensis by Capillary Electrophoresis and its Antitumour Activity~~ 相似文献
515.
Rui GUO. En Yong DING* Key Laboratory of Cellulose Lignocellulosics Chemistry Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou Graduate School of the Chinese Academy of Sciences Beijing 《中国化学快报》2006,(5)
The κ-carrageenan comes from a family of linear water-soluble polysaccharides extracted from different species of marine red algae with a primary structure of an alternating disaccharide with repeating unit of 3-linked β-D-galactose 4-sulfate and 4-link… 相似文献
516.
Synthesis and Characterization of Amphiphilic Block Copolymer Containing PVP and Poly(5-benzyloxytrimethylene carbonate) 总被引:2,自引:0,他引:2
Ying Xia WANG Feng HE Ren Xi ZHUO* Key Laboratory of Biomedical Polymers of Ministry of Education Department of Chemistry Wuhan University Wuhan 《中国化学快报》2006,17(2)
Amphiphilic block copolymers have attracted great interest recently, especially for thebiomedical uses1, . The hydrophilic blocks improve the biocompatibility of copolymer, 2while the hydrophobic blocks enhance the mechanics of the material and providever… 相似文献
517.
ZHOU Jin-xia ZHANG Yong-chun GUO Xin-wen * State Key Laboratory of Fine Chemical Dalian University of Technology Dalian P. R. China 《高等学校化学研究》2005,21(2):217-219
Introduction Separation,recoveryofolefinorremovalof tracequantitiesofolefinfromitsmixturesbyusing π-complexatonisamostpromisingsolution,com- paredwithenergy-intensivedistillationorotheral- ternatives.π-Complexationisasubgroupofchemi- calcomplexationwhereamixtureisbroughtinto contactwithasecondphasecontainingacomplex- ingagent[1].Forexample,theadsorbentscontain- ingAg+orCu+canselectivelyadsorbolefinfroman ethylene/ethaneorpropylene/propanemixture. Becausetheπ-complexationbondsarestronger th… 相似文献
518.
Yu Hua ZHANG Wei Qiang ZHANG Yu Gang CHEN Zhi CHEN Xin Yi ZHU Huan Wang JING Yuan Qi YIN* State Key Laboratory for Oxo Synthesis Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 《中国化学快报》2001,(1)
Due to the framework chirality optically active clusters can provide the proof that a cluster as a whole, and not one of its fragments, acts as a catalyst, most of the work have been directed to the synthesis of tetrahedron-type chiral clusters1-3. However, there remains another major problem to obtain the pure enantiomers. Although Vahrenkamp had obtained some pioneering results in this area before 19901, only several racemic chiral clusters have been separated into pure enantiomers until now… 相似文献
519.
Xin Cheng LIAO Xing Wang WANG Jing Chao TAO* Department of Chemistry Zhengzhou University Zhengzhou 《中国化学快报》2002,13(10)
Crown compounds offer a variety of interesting functions based on their specific bindings of organic guest species1,2. In particular, they can act as carriers in ion- extraction, membrane transport, and phase-transfer reactions. In contrast to the large variety of synthetic ionophores for cation transport, there are only a few examples of synthetic anion transport ionophores. Therefore, it appears highly desirable to search for a new class of ionophores with excellent transport abilities fo… 相似文献
520.
HE Feng-qi WANG Bao-lei LI Zheng-ming* Elemento-Organic Chemistry Institute State-Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin P. R. China 《高等学校化学研究》2006,(6)
IntroductionPlants have a more extensive biosynthetic capacitythan animals, which is attributed to the fact that ani-mals rely on their diet for the supply of many biochemi-cal compounds and their precursors. Owing to thisdifference, plants contain numero… 相似文献