Solvable <Emphasis Type="Italic">D</Emphasis><Subscript>2</Subscript>-groups

Let G be a finite group, Irr¹(G) be the set of nonlinear irreducible characters of G and cd¹(G) the set of degrees of the characters in Irr¹(G). A group G is said to be a D₂-group if|cd¹(G)|=|Irr¹(G)|-2. In this paper, we give a complete classification of solvable D₂-groups.     

Corona[5]arenes Accessed by a Macrocycle-to-Macrocycle Transformation Route and a One-Pot Three-Component Reaction

Corona[5]arenes, a novel type of macrocyclic compound that is composed of alternating heteroatoms and para-arylenes, were synthesized efficiently by two distinct methods. In a macrocycle-to-macrocycle transformation approach, S₆-corona[3]arene[3]tetrazine underwent sequential S_NAr reactions with HS-C₆H₄-X-C₆H₄-SH (X=S, CH₂, CMe₂, SO₂, and O) to produce the corresponding corona[3]arene[2]tetrazines. Different corona[3]arene[2]tetrazine compounds were also constructed in a straightforward manner by a one-pot three-component reaction of HS-C₆H₄-X-C₆H₄-SH (X=S, CH₂, CMe₂, SO₂, and O) with diethyl 2,5-dimercaptoterephthalate and 2 equiv of 3,6-dichlorotetrazine under very mild conditions. All corona[5]arenes adopted 1,2,4-alternate conformational structures in the crystalline state yielding similar nearly regular pentagonal cavities. Both the cavity size and the electronic property of the acquired macrocycles were fine-tuned by the nature of the bridging element X.     

Rees–Shishikura’s theorem for geometrically finite rational maps

In this paper, we generalize Rees–Shishikura’s theorem to the class of geometrically finite rational maps.     

通用有限元系统实现无限域波动仿真方法

在有限元模型中加入人工边界,可以进行无限域波动仿真。本文将介绍一种改进的Higdon人工边界,并通过适当的变换形式,将其在通用有限元软件上实现。最后通过数值实验验证了这种方法具有良好的稳定性和计算精度,并且实施简单方便,其他人工边界条件可参照本文方法,通过变换形式在通用有限元程序中实现。     

Application of a new fast multipole BEM for simulation of 2D elastic solid with large number of inclusions

A fast multipole method (FMM) is applied for BEM to reduce both the operation and memory requirement in dealing with very large scale problems. In this paper, a new version of fast multipole BEM for 2D elastostatics is presented and used for simulation of 2D elastic solid with a large number of randomly distributed inclusions combined with a similar subregion approach. Generalized minimum residual method (GMRES) is used as an iterative solver to solve the equation system formed by BEM iteratively. The numerical results show that the scheme presented is applicable to certain large scale problems. The project supported by the National Nature Science Foundation of China (10172053) and the Ministry of Education     

ELASTIC－PLASTIC CONSTITUTIVE MODELS BASED ON THE MULTIPLICATION PROCESSES OF DEFORMED GRAINS

（何宗彦）ＥＬＡＳＴＩＣ－ＰＬＡＳＴＩＣＣＯＮＳＴＩＴＵＴＩＶＥＭＯＤＥＬＳＢＡＳＥＤＯＮＴＨＥＭＵＬＴＩＰＬＩＣＡＴＩＯＮＰＲＯＣＥＳＳＥＳＯＦＤＥＦＯＲＭＥＤＧＲＡＩＮＳ￥ＨｅＺｏｎｇｙａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇｉｎｅｅｒＭｅｃｈａｎｉ...     

原子力／摩擦力显微图象的分析与测量

用表面粗糙度评定方法和分形几何方法，结合原子力／摩擦力显微图象的特点，编制了包括Ｒａ，Ｒｑ，Ｓｍ，Ｓ，λａ，λｑ及高度分布、承载率曲线、相关函数、功率谱和分形维数等参数的图象分析与测量的ＦＯＲＴＲＡＮ程序；用ＳＴＲ－１８０和ＳＴＲ－１０００标样作了高度标定，对国产Ｎａｔｕｒｅ磁带和进口Ｓｏｎｙ磁带的原子力／摩擦力显微图象进行了分析测量．结果表明：Ｎａｔｕｒｅ磁带的粗糙度和粒度均比Ｓｏｎｙ磁带的大；微摩擦力与表面轮廓及表面轮廓斜率之间均有良好的对应关系．     

武汉地区地震效应影响研究

虽然武汉市地震影响及地震危险性的水平较低 ,强震也不是武汉市工程地质环境的主要问题 ,但在城市生命线工程和高层超高层建筑方面必须考虑单体抗震设防。而且 ,随着武汉市城市建设的不断发展 ,地震效应影响逐渐成为武汉市工程地质环境评价的一个重要因子。文章在分析了武汉地区地震动衰减规律 ,进行了地震危险性评价 ,深入研究了各土层动力参数性质的基础上 ,指出武汉地区地震地面破坏主要存在砂土液化和软土震陷两种型式及各自可能的空间分布.