计算机研究材料科学的理论与实践

材料科学既是计算机应用的一个重要领域，也是计算机发展的工业基础学科，结合计算机在材料科学领域的应用，比较了从微观结构到物理性质、从数值分析到工艺过程模拟、从传统计算到智能处理等方面的计算机实验方法，探讨了计算机研究材料科学的理论和实践的发展趋势。     

电介质薄膜导热系数的尺寸效应

为研究电介质薄膜中的导热机制以及薄膜厚度对导热系数的影响 ,以氩的 FCC晶体为模型 ,采用分子动力学方法计算了厚度约为 2～ 10 nm的薄膜的法向导热系数。计算得到对应于 12 0 K的薄膜导热系数显著低于大体积实验值 ,并随薄膜厚度的减小而降低 ;即纳米薄膜的晶格导热系数具有明显的尺寸效应。当薄膜厚度减小至纳米量级时 ,即使在较高温情况下 1.3ΘD,晶体边界对声子的散射也将起重要作用。对氩晶体分别选取了 L ennard- Jones作用势和一种软球作用势 ,考察了不同势能模型对于模拟结果的影响     

Surface Treatment of UHMWPE Fibers for Adhesion Promotion in Epoxy Polymers

Surface of Ultra-high molecular weight polyethylene （UHMWPE） fiber were treated by chromic acid chemical etching, pyrrole chemical vapour phase deposition and the complex of these two methods, respectively. The change of surface properties and structure of fibers were discussed by Fiour Transform Infrared Spectroscope （FTIR）, Dynamic Mechanical Analysis （DMA） and Scanning Electron Microscope （SEM）. The results show that some new oxygenous groups could be found on surface of UHMWPE fiber after chromic acid chemical etching, which enhanced intemolecular interaction with polypyrrcle. The adhesion of the fiber and resin natrix increased after pyrrole chemical vapour deposition. When chromic acid etching combined with pyrrole chemical vapor deposition, the treated fiber not only has the same properties as original fiber bat also outstanding adhesion to epoxy resin matrix, and its composites have better mechanic properties shear strength）, resulting from intemolecular interaction treated fiber and polypyrrole.     

PMO与两可亲核试剂的双重反应性——微扰理论在有机化学中的应用研究Ⅷ

本文介绍了用于分析电子授-受反应过程的普通微扰方程,通过考查反应过程的电荷控制和轨道控制,从而半定量地解释和预测了具有双重反应性的两可亲核试剂的反应选择性。 我们曾用分子轨道微扰理论的普通方程(GP方程)半定量地解释了某些环加成反应的反应性、周边选择性、次级效应以及烯烃和苯环的亲电反应性,本文试用类似的考虑方法,分析电子授-受过程的电荷控制和轨道控制,从而解释和预测具有双重反应性的两可亲核试剂的反应选择性。     

高分子量PAN聚合体溶解工艺条件

用不同的溶解方法对高分子量PAN聚合体进行了溶解实验，结果表明：采用高速剪切乳化机进行溶解的方法能够显缩短溶解时间，搅拌的助溶作用也很明显．溶解温度、时间、浓度等工艺参数对溶液的性能也有影响．     

改进的总包性立方型状态方程

改进了Ｍａｒｔｉｎ提出的总包性立方型状态方程．验证表明，Ｍａｒｔｉｎ总包性立方型状态方程为本文改进总包性立方型状态方程的特例，由改进后的总包性立方型状态方程可推导出迄今为止前人提出的各种类型的立方型状态方程，且较Ｍａｒ－ｔｉｎ方程的推导更为简捷．此外，在Ｖｅｒａ－Ｐｒａｕｓｎｉｔｚ的普遍化ｖａｎｄｅｒＷａａｌｓ稠密流体理论基础上，结合本文给出的普遍化ｖａｎｄｅｒＷａａｌｓ流体的分子位能表达式，导出了改进的总包性立方型状态方程     

瓦斯流动的分子动力模拟中势函数的研究

势能函数作为分子动力模拟的重要问题,它的选取及求解成为这一研究的热点．探讨了分子动力模拟中所涉及的一系列势能函数,选取了所研究的煤层瓦斯流动分子动力模拟所需要的势函数,并根据临界常数法求取了此函数所涉及到的势能参数。最后计算出一个甲烷分子与截断半径处另一分子之间的L-J势能,为后期的模拟研究奠定了基础。     

The complete mitochondrial genome of the Chinese Sika deer (Cervus nippon Temminck, 1838), and phylogenetic analysis among Cervidae,Moschidae and Bovidae

The complete mitochondrial genomes of the Sichuan Sika deer (Cervus nippon sichuanicus) and the South China Sika deer (Cervus nippon kopschi) were determined. Their sizes were 16,429 and 16,428 base pairs, respectively. The similarity of the mitochondrial DNA genome among subspecies of the Chinese Sika deer was calculated, and the values estimated from complete nucleotide sequences and entire amino-acid sequences were 98.4–99.9% and 99.7–99.9%, respectively. Molecular phylogenetic analyses were conducted using maximum parsimony and Bayesian inference methods based on the sequences of 12 concatenated heavy-strand encoded protein-coding genes. The consensus of phylogenetic trees supported the monophyly of Moschidae, Cervidae and Bovidae, and placed Moschidae as a sister group to Cervidae/Bovidae. The relationships among Chinese Sika deer inferred from the phylogenetic analysis were inconsistent with subspecies designations and the present geographic distribution. Our complete mitochondrial genomes will be available as important and basic data for phylogenetics, breeding, genetics and conservation in Cervidae.     

Use of morphological and molecular data to identify three new sibling species of the genus Munida Leach, 1820 (Crustacea,Decapoda, Galatheidae) from New Caledonia

Three cryptic species of the genus Munida from New Caledonia, previously identified as M. tuberculata Henderson, , M. notata Macpherson, and M. clinata Macpherson, , are described and illustrated. The three species are identified by subtle and constant morphological characters, which match clear differences in molecular sequences (16S rDNA and COI genes). The results also confirm the importance of several of these characters (e.g. length of the antennular and antennal spines) in the taxonomy of the genus Munida.     

电子关联对聚乙炔中双激子湮灭过程的影响

在SSH哈密顿基础上引进弱电子关联,对反式聚乙炔链中双激子的湮灭过程实施了分子动力学模拟.电子关联的引入延缓了链中激子的湮灭过程,关联强度U=0eV时,激子的湮灭时间约在t=84fs,计入四个近邻格点上的弱电子关联作用,湮灭时间明显减慢,约为t>100fs.随着弱关联强度的增加,湮灭时间逐渐延长.计算结果表明,在计算有机材料激子快速响应过程中计入电子关联是十分必要的.