承受拉-扭组合载荷的薄壁圆筒屈服时产生塑性流动的条件

提出了在无外力作功的情况下，具有Bauschinger效应的弹塑性材料处于屈服状态产生自发的塑性流动时应满足的条件．这个条件不仅与材料的力学性能有关，而且还处决于材料的具体的载荷边界条件和变形．举例说明了承受拉一扭组合的薄壁圆筒中，采用组合强化模型时，产生塑性流动的具体条件．     

Symmetry classification of quasi-linear PDE’s containing arbitrary functions

We consider the problem of performing the preliminary “symmetry classification” of a class of quasi-linear PDE’s containing one or more arbitrary functions: we provide an easy condition involving these functions in order that nontrivial Lie point symmetries be admitted, and a “geometrical” characterization of the relevant system of equations determining these symmetries. Two detailed examples will elucidate the idea and the procedure: the first one concerns a nonlinear Laplace-type equation, the second a generalization of an equation (the Grad–Schlüter–Shafranov equation) which is used in magnetohydrodynamics.     

基于Delaunay三角法的电压门控钾离子通道的分类和拓扑结构识别

本文构建了一个Delaunay模型对电压门控钾离子(Kv)通道进行预测。该方法通过建立一系列带有隐含变量的单纯形来分类电压门控钾离子通道,然后通过未知序列在主成分空间里面的投影来预测结构。结果表明该模型无论是在分类和结构预测上均可以得到很好的结果。     

受压矩形截面柱在塑性阶段的缺陷敏感性分析

对加载到塑性阶段的矩形截面柱，本文研究了几何缺陷对屈曲的影响，在分析中考虑了弹性卸载的影响，求出了荷载、缺陷大小及分叉模态幅值之间的精确渐近关系式，结果表明在塑性阶段最大承载力对小缺陷非常敏感，但当缺陷大小达到某一值后，可能不存在最大载荷。     

非球面塑料透镜注射型芯工艺探讨

本文来自于作者的实践。介绍了加工方法及测量问题。重点叙述了加工中的一些关键,同时也提供了国内外在这方面的进展情况。     

WAVELET TRANSFORM IN FRACTAL IMAGE ENCODING

This paper presents some results of the relation between wavelet transform and fractal transform. The wavelet transform of the attractor of fractal transform posseses translational and scale invariance. So we speed the fractal image encoding by testing the invariance of the wavelet transform appropriate for image encoding. The classfication scheme of range blocks by wavelet transform is given in this paper.     

Experimental investigation on large deflection response of a frame impacted by a moving body

This paper reports on the experimental investigation of the dynamic large deflection response of a portal frame impacted at its midspan by a body moving at a certain speed. Both the deflection and velocity vs. time curves of the midspan and the dynamic history of a number of desired locations were recorded during the process of response. On the basis of the test data, the momentum and kinetic energy conversion between the frame and the moving body in the impact process are realized, and the occurrence and expansion of plastic regions are described. Investigation results show that the initial collision is approximately ideally inelastic, and that the elastic deformation plays a considerable role in the response though the input energy is much larger than the maximum elastic energy capacity of the beam member; therefore, in a general impact, the energy ratio should not be regarded as a sufficient criterion for a rigid—plastic solution. The ratios of the impulse transferred to and the energy absorbed by the frame in the initial collision to that carried by the moving body before impact is only related to the ratiobetween the equivalent mass of the frame paticipating in the initial collision and the mass of the impacting body, having nothing to do with the impacting velocity to a certain extent.     

On a question of H. Kraljević

In this paper, assuming a certain set-theoretic hypothesis, a positive answer is given to a question of H. Kraljevi, namely it is shown that there exists a Lebesgue measurable subsetA of the real line such that the set {c R: A + cA contains an interval} is nonmeasurable. Here the setA + cA = {a + ca: a, a A}. Two other results about sets of the formA + cA are presented.     

The Binet-Pexider functional equation for rectangular matrices

IfK is a field of characteristic 0 then the following is shown. Iff, g, h: M _n (K) K are non-constant solutions of the Binet—Pexider functional equation