Off-Optimum Cure of Aerospace Epoxy Adhesives

Four epoxy film adhesives used in aircraft manufacture and repair have been examined to establish the effect of deviation from the cure cycle specified by the manufacturer. In addition to the variation of the cure cycle, two surface preparations of the aluminium adherends (chromic acid etch or grit blast followed by silane treatment) were evaluated. Thermal analysis was used to examine the cure envelope of the adhesive, and its extent of cure and glass transition temperature. The adhesive properties were assessed by shear strength (in both single lap joints and in Iosipescu configuration), durability (Boeing wedge test) and chemical resistance to selected aggressive fluids. The sensitivity of the performance of a particular adhesive to offoptimum cure conditions depends on its composition and needs to be determined, not predicted.     

济钢350m^3高炉高富氧生产技术

分析了济钢350m^3高炉高富氧对产量,理论燃烧温度,炉况顺行状况,焦比和生产效益的影响,高富氧可提高产量,但升高焦比和高炉理论燃烧温度,一定程度上影响高炉顺行,存在富氧效益最大化的适宜富氧率.高炉生产应低富氧高喷煤,根据钢目前的情况,富氧率经2%-3%为宜.     

不规则I型和L型横截面形状薄壁杆件的横向弯曲稳定分析

根据势能驻值原理,采用转换B3样条函数模拟杆件横截面的翘曲位移场,文[8]提出了用于分析在横向荷载作用下薄壁杆件稳定问题的样条有限杆元法。方法适用于任意横截面形状和任意边界条件的薄壁杆件,考虑了杆壁中面上剪切变形的影响,能很好地描述剪力滞后现象。本文讨论了不规则I型截面简支梁和L型截面简支梁的屈曲分析,数值算例的结果表明了方法的灵活性、精确性和有效性。     

推进波作用下的底泥起动

在介绍推进波作用下底泥起动特点的基础上，将上层水体作为粘性流体，底泥作为粘弹性体，推导了推进波作用下泥床面剪应力的表达式，并根据试验结果，给出了推进波作用下底泥起动时的床面剪应力与底泥流变参数的关系。     

GCL——一种新型复合土工材料的特性及应用综述

 对GCL基本产品的结构类型、水力特性、强度特性、隔气性等作了概括性的介绍，通过图解说明了GCL在环境工程和水利工程中的应用情况，最后指出了其在工程应用中应注意的几点问题。     

Effects of shear flow on long-ranged correlations,spinodal demixing kinetics,and the location of the critical point and cloud point

A derivation of an expression for the shear rate-dependent Ornstein Zernike structure factor is discussed, together with the resulting anomalous behavior of the turbidity. The predicted scaling behavior of the turbidity, comprising the effect of both temperature and shear rate, is in good agreement with experiments on binary fluids. Then initial spinodal decomposition is discussed, and an explicit expression for the time- and shear rate-dependent effective diffusion coefficient is derived, which shows all the typical characteristics of anisotropic light scattering patterns that are observed experimentally for binary fluids. Next it is shown that the spinodal is shifted linearly with the (bare) Peclet number for not too large Peclet numbers, whereas the cloud point is singularly displaced into the unstable region due to a shear now. This is in agreement with an experiment on a two-polymer/solvent mixture and binary fluid mixtures. It is argued that light scattering is useless to determine the location of the spinodal of a sheared system.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

粘弹性圆柱壳在轴向恒压下的动力稳定性

基于Timoshenko-Mindlin假设,得到考虑粘弹性的各向同性圆柱壳及纤维增强正交铺设层合圆柱壳在轴向恒压下的动力学方程。文中对两端简支的圆柱壳进行了分析,依Laplace变换,导出动力稳定的特征方程,由Routh-Hurwitz判据建立动力稳定性条件,对两类圆柱壳讨论了横向剪切变形的影响。     

也谈轻型钢结构房屋柱基设计

对柱脚抗剪键的设置和计算中所取用的荷载组合提出个人观点,同时对轻钢结构柱脚螺栓受拉计算提出注意事项.     

EDA介质快慢横波时差和振幅-方位曲线的实验分析

在含垂直定向裂隙的各向异性（EDA）介质中，地震快、慢横波传播的时差及振幅随裂隙（缝）方位变化曲线能反映裂缝的密度、走向和介质的性质，这对多波地震资料的处理、解释有着重要意义。但受观测条件限制以及噪声的影响，在横波分裂记录上，同相轴往往会出现扭曲、倾斜和不规则抖动等现象，给快、慢横波时差的求取和振幅-方位曲线的绘制带来误差。设计了EDA介质物理模型，并利用岩石超声波测量系统获得了快、慢横波记录；分析记录可知，在相同传播方向的分裂横波具有走时和传播速度不随裂缝方位变化的恒定性特征；以此为基础，提出了利用平均法和瞬时振幅法来计算快、慢横波的走时时差和绘制振幅-方位曲线，以提高精度。利用物理模型实验得到的2个正交横波（S1波与S2波）的快、慢横波记录，分别用平均法和瞬时振幅法计算了快、慢横波走时的平均值、时差和均方差，并绘制了相应的振幅一方位曲线。结果表明，采用上述2种方法，消除了同相轴扭曲、倾斜和不规则抖动等对计算结果的影响，时差的计算是可靠的，振幅一方位曲线的绘制是合理的。