几种高性能纤维束的冲击动力学性能实验研究

利用直拉式Hopkinson装置研究了碳纤维、无碱E玻璃纤维、Kevlar 4 9/96 4 /96 4c、Twaron2 0 0 0、DyneemaSk6 6等纤维的动态拉伸性能。与准静态加载条件下相比 ,纤维束的拉伸强度基本与应变速率无关(玻璃纤维除外 ) ,而纤维束的弹性模量和失效应变随应变率的升高而明显变大。从高分子物理以及两种无机纤维的内部微观结构特征对纤维的力学性能与加载速率的关系进行了初步的物理阐释。讨论了实验数据的发散原因。     

界面裂纹问题的解析—变分解法及其在复合材料盖板胶接件中的应用

本文根据穆斯海里什维利求解各向同性平面问题与列赫尼兹基求解各向异性平面问题的广义复变函数理论与本征函数展开法,分析了复合材料盖板胶接件的分层问题,得到了精确满足所有基本方程、裂纹表面边界条件与层间连续条件的位移场与应力场本征展开式.进而利用分区广义变分原理满足裂纹表面以外的边界条件并由此确定应力强度因子.     

QUADRATURE METHODS FOR HIGHLY OSCILLATORY SINGULAR INTEGRALS

We address the evaluation of highly oscillatory integrals,with power-law and logarithmic singularities.Such problems arise in numerical methods in engineering.Notably,the evaluation of oscillatory integrals dominates the run-time for wave-enriched boundary integral formulations for wave scattering,and many of these exhibit singularities.We show that the asymptotic behaviour of the integral depends on the integrand and its derivatives at the singular point of the integrand,the stationary points and the endpoints of the integral.A truncated asymptotic expansion achieves an error that decays faster for increasing frequency.Based on the asymptotic analysis,a Filon-type method is constructed to approximate the integral.Unlike an asymptotic expansion,the Filon method achieves high accuracy for both small and large frequency.Complex-valued quadrature involves interpolation at the zeros of polynomials orthogonal to a complex weight function.Numerical results indicate that the complex-valued Gaussian quadrature achieves the highest accuracy when the three methods are compared.However,while it achieves higher accuracy for the same number of function evaluations,it requires signi cant additional cost of computation of orthogonal polynomials and their zeros.     

RUIN PROBABILITY IN A SEMI-MARKOV RISK MODEL WITH CONSTANT INTEREST FORCE AND HEAVY-TAILED CLAIMS

In the present paper, we consider a kind of semi-Markov risk model （SMRM） with constant interest force and heavy-tailed claims~ in which the claim rates and sizes are conditionally independent, both fluctuating according to the state of the risk business. First, we derive a matrix integro-differential equation satisfied by the survival probabilities. Second, we analyze the asymptotic behaviors of ruin probabilities in a two-state SMRM with special claim amounts. It is shown that the asymptotic behaviors of ruin probabilities depend only on the state 2 with heavy-tailed claim amounts, not on the state 1 with exponential claim sizes.     

一类振荡奇异积分

考虑了一类振荡奇异积分算子L^p性质．     

论行政赔偿范围的扩大

对我国目前的行政赔偿范围进行了反思。认为我国现行的《国家赔偿法》主要以列举方式确定的行政赔偿范围,极大限制了行政赔偿范围。建议采取“概括加否定排除式”的立法模式扩大行政赔偿范围,将行政规章以下的抽象行政行为、行政不作为行为和精神损害赔偿纳入行政赔偿范围。     

Electroactive shape memory cyanate/polybutadiene epoxy composites filled with carbon black

Electroactive shape memory composites were synthesized using polybutadiene epoxy(PBEP) and bisphenol A type cyanate ester(BACE) filled with different contents of carbon black(CB). Dynamic mechanical analysis(DMA), scanning electron microscopy(SEM), electrical performance and electroactive shape memory behavior were systematically investigated. It is found that the volume resistivity decreased due to excellent electrical conductivity of CB, in turn resulting in good electroactive shape memory properties. The content of CB and applied voltage had significant influence on electroactive shape memory effect of developed BACE/PBEP/CB composites. Shape recovery can be observed within a few seconds with the CB content of 5 wt% and voltage of 60 V. Shape recovery time decreased with increasing content of CB and voltage. The infrared thermometer revealed that the temperature rises above the glass transition temperature faster with the increase of voltage and the decrease of resistance.     

大学生体育行为与心理健康关系的研究

对河南省部分高校大学生的体育行为和心理健康现状的调查结果表明，目前大学生的心理健康现状并不乐观，很多学生具有不同程度的心理障碍和潜在问题。经对体育行为与心理健康之间的相关性进行分析，针对存在的问题提出了可行性建议，希望能为高校构建健康教育体系提供理论依据。     

稳定相方法与一类振荡积分的渐近

主要对稳定相方法的一般结论进行了推广,给出了一类更一般的振荡积分的渐近情况。基于一般稳定相方法给出了积分的渐近条件,严格证明了主要定理,并讨论了此类积分渐近结果的重要应用。