多晶金刚石复合材料的某些质量问题

 本文报道了在研制多晶金刚石复合材料（PDC）时碰到的一些质量问题及其造成的原因和解决办法。     

采用S型控制算法的步进电机控制器

为了改善步进电机的启动特性,将S型算法应用到步进电机的启动过程中,设计一种基于S3FN41F微处理器的步进电机嵌入式控制系统,并将其应用于液晶屏(LCD)压合器中.对该算法进行实现与验证,结果表明:采用S型控制算法的步进电机控制器能够更好地控制步进电机的运行,具有失步率低、振荡小、生产效率高等优点,能更好地应用于高速、高精度的压合系统中.     

一类模糊线性规划的新算法

提出了一种将模糊线性规划转化为常规线性规划的方法,即将目标系数是三角模糊数的线性规划转化为目标系数为L—R型模糊数的线性规划,然后转化为模糊线性多目标规划,并对其模糊线性多目标规划用了一种新的算法求解．最后通过实例说明了该算法的有效性．其运算结果表明：新算法比一般的算法迭代过程更为简洁,收敛速度更快,容易用matlab在计算机上操作．     

多级分层——定位导向一体化模式在背越式跳高教学中应用研究

根据运动技能生成机制和动作技能形成过程的思想和理论设计多极分层——定位导向一体化模式。对其实证研究结果表明：该理论模式具有针对性强,整体性好、功效性强和简单易行等特征。在背越式跳高教学应用中显示：其理论与方法的应用可促进和加快动作技能早日形成,并同时具有预防和纠正错误动作的功效,优化了教学过程,使教学对象综合受益性优于常规教法,能更加有效的提高背越式跳高的教学效果。     

基于铺层参数的复合材料耐压壳协同优化设计

在给定的材料性能条件下,以耐压壳纤维体积分数和层合板厚度为设计变量,以结构质量最小为优化目标进行复合材料耐压壳的布局优化;以铺层参数作为优化变量,综合考虑结构的稳定性及其材料强度,实现了结构铺层方式的优化设计;通过协调各子系统优化结果,实现了适用于潜水器复合材料耐压壳结构/材料一体化的协同优化设计.结果表明:耐压壳结构质量较优化前的降幅为20.57%,临界失稳压力为30.78MPa,失效指数为0.675,优化结果达到预期效果.所提出的基于铺层参数的协同优化方法能够对复合材料耐压壳进行优化设计,解决了直接以铺层角作为设计变量的优化效率低的问题.     

A study of the in situ transverse tensile lamina strength and the classical solution of the opening mode crack in a 0/90/0 laminate

In this paper, the classical solution of the opening mode crack in the 90° layer of 0/90/0 laminates has been determined by means of Fourier transformations and the procedure of Copson for a pair of dual integral equations. The fracture behavior and the in situ transverse strength of the 90° layer have been quantitatively studied in graphite/epoxy laminates, based on the solution obtained above. The results show that the stress intensity factor of this kind of laminates, which is different from that of a single unidirectional 90° layer, decreases with the increase in thicknessb, or modulusE _L orG _LT of the 0° layer and also decreases with the decrease in the thickness of the 90° layer. So the lamination effect manifests itself and thein situ transverse strength of the 90° layer is thereby enchanced. The theoretical calculations agree with the experimental data presented by D.L. Flaggs. Supported by National Natural Science Fundation of China.     

Infinitely many hyperbolic 3-manifolds which contain no Reebless foliation

We investigate group actions on simply-connected (second countable but not necessarily Hausdorff) 1-manifolds and describe an infinite family of closed hyperbolic 3-manifolds whose fundamental groups do not act nontrivially on such 1-manifolds. As a corollary we conclude that these 3-manifolds contain no Reebless foliation. In fact, these arguments extend to actions on oriented -order trees and hence these 3-manifolds contain no transversely oriented essential lamination; in particular, they are non-Haken.

     

The algebraic theory of the fundamental germ

This paper introduces a notion of fundamental group appropriate for laminations.     

平板层流速度边界层动态问题分析

从边界层动态微分方程出发，按照速度边界是层有关理论，推导出了边界层动态积分方程。在对边界层速度合理假设的基础上，求解了动态积分方程，给出了依时间和空间变化的边界层厚度响应函数。