Dynamic rheological properties and bread‐making qualities of wheat gluten: effects of urea and dithiothreitol

Controlled stress rheometry differentiated glutens from the cultivars under study into ‘extra‐strong’, strong and weak on the basis of their elastic and viscous moduli measured in the linear domain. The mechanical spectra of different glutens revealed no qualitative differences, but exhibited large quantitative differences in the magnitude of the dynamic measurements, ie elastic modulus, G′, viscous modulus, G″, and loss tangent, tanδ. Both covalent and non‐covalent interactions appeared to contribute to these differences. However, disulfide cross‐links proved to be especially important determinants of differences in the elastic characteristics of the glutens. The present study indicated that dynamic rheological parameters of glutens were related to their bread‐making performance, as evidenced by the significant correlations between the dynamic moduli of the glutens and loaf volume. Copyright © 2004 Society of Chemical Industry     

聚丙烯酸酯弹性乳液聚合研究

本介绍在丙烯酸酯乳液共聚反应中，在乳化剂总用量一定的条件下，改变阴离子型和非离子型乳化剂的配比以及改变非离子型乳化剂的种类，制得一系列Tg=-10℃的弹性乳液和Tg=27℃乳液。用这两种乳液做与水泥配伍实验，并用这两种乳液与一定浓度的钙离子溶液相混合，检测乳液与它们相互混合的稳定性。     

磁场作用下液晶材料参数和锚定能的测试

介绍了在磁场作用下液晶材料的介电常数各向异性，磁化率各向异性，展曲弹性常数，扭曲弹性常数，弯曲弹性常数，以及在不同锚定强度下液晶分子与取向基板间的极化锚定能，方位锚定能的测试原理和测试技术。同时简单介绍了液晶材料的取向有序度，易取向轴和磁相干长度的磁场测试方法。     

围岩性质对最大主应力赋存状态的影响

通过对北京科技大学近几年在我国四个金属矿山实测结果的分析，对最大地应力的分布规律进行了探讨，指出最大地应力的大小与测点深度和围岩性质均呈现良好的线性关系。     

发射初期弹带材料对弹带及弹托中应力的影响

应用“自动动态增量非线性分析”程序，计算了某高初速杆式穿甲弹在发射初期，当弹带为尼龙、铜质等不同材料时，弹内动态应力和弹带压力变化情况；并就尼龙弹带前倾角的变化对应力分布的影响作了计算分析，确定了尼龙弹带在给定尺寸情况下的弹带压力分布、弹带变形情况等，最后就几种情况作了较详细的分析探讨。     

Random excitation of nonlinear elastic structures with internal resonances

The influence of random vibration on the design of mechanical components has been restricted to the linear theory of small oscillations. However, this theory is inadequate and fails to predict the complex response characteristics which may be observed experimentally and can only be predicted by employing the nonlinear theory. This paper presents a brief overview of the basic nonlinear phenomena associated with nonlinear random vibration. An example of a clamped-clamped beam under filtered white noise excitation in the neighbourhood of 1:1 internal resonance condition is considered. Three approaches are employed to examine the response and stochastic bifurcation of the beam coupled modes. These are the Fokker-Planck equation together with closure schemes, Monte Carlo simulation, and experimental testing. The analytical results are compared with those determined by Monte Carlo simulation. It is found that above a critical static buckling load the analytical results fail to predict the snap-through phenomenon, while both Monte Carlo simulation and experimental results reveal the occurrence of snap-through. The bifurcation of second mode is studied in terms of excitation level, internal detuning and damping ratios. It is found that below the critical load parameter, the response statistics do not significantly deviate from normality. Above the critical value, where snap-through takes place, the response is strongly non-Gaussian. This research is supported by a grant from the National Science Foundation under grant number MSS-9203733 and by additional funds from the Institute for Manufacturing Research at Wayne State University.     

几种旋转接头在铝板轧机上的应用

对铝板轧机成套设备中使用的旋转接头的结构进行了分析，介绍了改造后旋转接头的详细结构。     

基于神经网络模型的某大坝混凝土弹性模量时变规律反演分析

基于人工神经网络的非线性映射特性，在三维有限元计算的基础上，结合大坝原型观测资料，提出了大坝参数时变规律的反演方法。以某混凝土重力坝的原型观测资料为例，利用该方法反演得出了该坝坝体混凝土弹性模量的变化规律。结果表明该方法是切实可行的，可应用于分析评价大坝材料参数的变化。     

A technique for analyzing elastodynamic responses of anisotropic laminated plates to line loads

A new technique is presented to modify the hybrid numerical method (HNM) proposed earlier by the authors for analyzing the responses of anisotropic laminated plates subjected to time-step and time-pulse line loads. In the modified HNM, eigenfrequencies and modal factor functions for wave modes in the plate are computed at equally spaced points on the wavenumber axis. In each interval of the points, the eigenfrequencies and modal factor functions are replaced by straight lines, and the inverse Fourier integrations are then carried out analytically. The proposed modification can significantly reduce the sampling points in the inverse integrations. The modified HNM is much more efficient than the original HNM, and can be used to compute not only near-field and short-time but also far-field and long-time responses for anisotropic laminated plates, without increasing the sampling points. Numerical examples are presented to demonstrate the modified HNM.     

聚氨酯弹性地坪涂料

简述了聚氨酯弹性地坪涂料的制备工艺，列举了该涂料的主要技术指标及测试结果。着重讨论了环氧树脂、弹性预聚物的各组分(线型聚醚、多元醇、甲苯二异氰酸酯)和预聚物的RNCOOH的控制及配漆时，NC0/0H当量比等因素对涂料性能的影响。