非紧集合上的Brezis-Nirenberg定理

本文证明了在非紧集合上的Brezis-Nirenberg定理的结构仍然成立。     

Experimental and FEM study of windshield subjected to high speed bird impact

Both experimental and finite element model (FEM) results are presented for the dynamic strength behavior of windshield subjected to bird impact. The experimental data taken from a series of high speed photographs are compared with the numerical results predicted by using FEM in which the windshield was modeled entirely with solid elements and the bird body was approximately simulated by an elastic-plastic material with failure element behavior. Effective plastic strain and element pressure were adopted as the failure criteria and once the pressure or the effective plastic strain of an element reached the critical value, the element would lose the tensile resistance capability completely. The deflection and stress distribution in the windshield were obtained. It is shown that the result from the finite element analysis agrees with those from the full-scale bird impact test. The project supported by the National Natural Science Foundation of China (10272011)     

电流变液体黏性变化趋势的试验研究

以微观试验和流变性能试验为手段，分别研究零电场下和在电场作用下的电流变液体黏性变化规律．研究结果表明：零电场下电流变液体的黏性与Krieger-Dougherty公式具有很好的拟合效果，其中逾渗临界值强依赖于悬浮液体中固体颗粒的性质并随工作温度变化．在电场作用下，电流变悬浮液体的黏度随剪切速率的变化规律分为3个阶段：即呈线性的启动段、非线性的幂定律模型流动段和宾汉模型流动段．研究结果为电流变效应工程应用提供依据．     

QUALITATIVE ANALYSIS OF DYNAMICAL BEHAVIOR FOR AN IMPERFECT INCOMPRESSIBLE NEO-HOOKEAN SPHERICAL SHELL

IntroductionIn applications, it is commonly considered that the phenomena of cavity formation,growth and run-through of adjacent cavities occur in materials as precursors to failure. Thesephenomena are mainly due to instability of materials. On the other …     

隐性心脑血栓病筛选的初步实验研究

通过对自然人群血栓状态和部分生化指标的检测，采用常规的统计分析，推断出正常人体外血栓参数的临界值分别为：长度３６．８３ｍｍ，干重４２．４４ｍｇ，线密度２．２８ｇ．ｍ＾－１，血栓状态与血液内的部分生化指标有弱的相关，分别是胆固醇与线密度相关，甘油三酯与血栓长度相关，β－脂旦白与干重相关。     

The bifurcation threshold value of the chaos detection system for a weak signal

Recently, it has become an important problem to confirm the bifurcation threshold value of a chaos detection system for a weak signal in the fields of chaos detection. It is directly related to whether the results of chaos detection are correct or not. In this paper, the discrimination system for the dynamic behaviour of a chaos detection system for a weak signal is established by using the theory of linear differential equation with periodic coefficients and computing the Lyapunov exponents of the chaos detection system; and then, the movement state of the chaos detection system is defined. The simulation experiments show that this method can exactly confirm the bifurcation threshold value of the chaos detection system.     

磁绝缘传输线振荡器中辐射场的非线性行为

 导出了磁绝缘传输线振荡器(MILO)中辐射场的非线性演化方程，并讨论了在临界值点附近可能出现非线性不稳定解的条件。结论是：(1)非线性增长速率与线性增长速率的比值g<1.2，且远离g+γ=1(γ为非线性相位增长率与线性相位增长率的比值)点时，出现非稳定解的失谐量临界值很小，而线性增长速率临界值临界值很大，容易出现非稳定解；(2)当g≥1.2时，任意小的失谐量都可以使场出现非稳定解；(3)线性增长速率越大，越不容易出现非稳定解。     

三相异步电动机电气参数较精确计算方法

本文根据异步电动机额定数据和等效电路,导出了异步电动机电气参数较准确的计算方法.     

三维自助式类渗流细胞自动机的临界值

本文研究三维自助式类渗流细胞自动机的临界值．得出临界值pc＝0的一些充分条件和必要条件．当pc＞0时，利用定向点渗流的临界值，给出了pc上、下界的显式估计．     

球面上皱褶花样的演化

文章从理论和实验两方面研究了通过控制柔性衬底的曲率来调控球面上应力诱导之皱褶花样的可行性.研究以Ag内核/SiO2壳层微结构为对象.结果表明,当球形衬底的曲率较小且应力刚超过临界值时,皱褶花样为三角铺排的凹痕结构;而当应力进一步增大和/或衬底的半径增大时,则出现迷宫形的花样.皱褶的周期长度和临界屈曲应力都随衬底半径的增大而增大.此方向上的研究对于理解大自然中许多花样(比如花叶序与皱纹)的产生和演化具有重要的意义.