Si-H, P-H 和 S-H 键离解能Alfa取代基效应研究

CBS-Q and G3 methods were used to generate a large number of reliable Si--H, P---H and S--H bond dissociation energies （BDEs） for the first time. It was found that the Si--H BDE displayed dramatically different substituent effects compared with the C--H BDE. On the other hand, the P---H and S--H BDE exhibited patterns of substituent effects similar to those of the N--H and O--H BDE. Further analysis indicated that increasing the positive charge on Si of XSiH3 would strengthen the Si--H bond whereas increasing the positive charge on P and S of XPH2 and XSH would weaken the P---H and S--H bonds. Meanwhile, increasing the positive charge on Si of XSiH2^＋ stabilized the silyl radical whereas increasing the positive charge on P and S in XPH＂ and XS＊ destabilized P- and S-centered radicals. These behaviors could be reasonalized by the fact that Si is less electronegative than H while P and S are not. Finally, it was demonstrated that the spin-delocalization effect was valid for the Si-, P- and S-centered radicals.     

原子谱项在二十面体场Ih中的分裂

世界性的C_(60)与C_(60)(球烯包合物的符号尚未统一,目前文献中有C_(60)和xdC_(60)等记法,本文采用前一种)研究热潮,使长期以来在化学领域中倍受冷落的二十面体群,I_h变得日益重要。尽管目前只有La、U、K、He等少数元素被封装进C_(60)笼内,但科学家们已经预言:许多元素、甚至一些分子总有一天将填入C_(60)或     

对称三对角线特征值问题的一个并行修正拟Laguerre算法

在拟Laguerre算法的基础上，提出了用修正拟Lagureer算法来求求解对称三角线特征值问题，并给出了算法的并行实现。     

分裂扩张的稳定自同构群

本文给出有限群的分裂的Abel扩张的稳定自同构群的计算.作为应用,给出了循环群的半直积的自同构群的结构,它包括了若干已知结果,如文[1]的全部结果,并解决了[1]提出的问题.     

非凸不可分优化线性近似Bregman型Peaceman-Rachford分裂算法

基于Peaceman-Rachford分裂算法,结合线性近似技术和Bregman距离,本文提出一种线性近似Bregman型Peaceman-Rachford分裂算法,用于求解目标函数带不可分结构的线性约束非凸优化问题.在常规假设下,得到算法的全局收敛性.在效益函数满足Kurdyka-Lojasiewicz性质前提下,论证算法的强收敛性.当KurdykaLojasiewicz性质关联函数为特殊结构时,分析并获得算法的收敛率结果.最后,初步数值试验说明算法有数值有效性.     

分裂四元数矩阵的奇异值分解及应用

利用i-共轭重新定义了分裂四元数矩阵的共轭转置,在此基础上借助复表示和友向量研究了分裂四元数矩阵的奇异值分解,并利用所得结果解决了分裂四元数矩阵的极分解和分裂四元数矩阵方程AXB-CYD=E.     

TENSILE STRENGTH FOR SPLITTING FAILURE OF BRITTLE PARTICLES WITH CONSIDERATION OF POISSON＇S RATIO

The core mechanism of comminution could be reduced to the breakage of individual particles that occurs through contact with other particles or with the grinding media, or with the solid walls of the mill. When brittle particles are loaded in compression or by impact, substantial tensile stresses are induced within the particles. These tensile stresses are responsible for splitting failure of brittle particles. Since many engineering materials have Poisson‘s ratios very close to 0.3, the influence of Poisson‘s ratio on the tensile strength is neglected in many studies. In this paper, the state of stress in a spherical particle due to two diametrically opposed forces is analyzed theoretically. A simple equation for the tensile stress at the centre of the particle is obtained. It is found reasonable to propose this tensile stress at the instant of failure as the tensile strength of the particle. Moreover, this tensile strength is a function of the Poisson‘s ratio of the material. As the state of stress along the z-axis in an irregular specimen tends to be similar to that in a spherical particle compressed diametrically with the same force, this tensile strength has some validity for irregular particles as well. Therefore, it could be used as the tensile strength for brittle particles in general. The effect of Poisson‘s ratio on the tensile strength is discussed.     

松弛算子分裂法线性收敛性分析的新框架

提出了一种新的分析框架来研究松弛算子分裂法的线性收敛性,可以将这种框架看成是经典的Krasnosel''-Mann迭代和Banach-Picard收缩的扩展形式.随后,将提出的这个框架应用于分析广义邻近点算法和松弛向前向后分裂算法的线性收敛性,其过程十分简洁和直接.