Behavior of preloaded RC beams strengthened with CFRP laminates

INTRODUCTION Externally bonded fiber reinforced polymer (FRP) composites can be used to improve the flexural strength of structural members. To evaluate the flex-ural performance of the strengthened members, it is necessary to study the flexural stiffness of FRP- strengthened RC members at different stages, such as pre-cracking, post-cracking and post-yielding. Up to now, only very few studies were focused on the structural members strengthened under pre-loading or pre-cracking (Arduin…     

Unit ball in high dimensions

In this article, we compute the volume V _n of the unit ball in an n-dimensional space. For n = 1, 2, 3, the volumes are respectively 2, π 4π /3, which are the length of interval [−1,1], area of a unit circle and volume of the unit sphere. The numbers V _n ‘appear’ to increase. But in fact this not so. In fact V _n tends to zero as n tends to infinity! K B Athreya is a Visiting Professor at IMI, Mathematics Department, IISc, Bangalore. He is a professor in the Mathematics Department of the Iowa State University, USA. His research interests include mathematical analysis, probability theory and its applications and statistics. His spare time is spent listening to Indian classical music.     

Practical realization of dual S arm antenna for beam steering applications

A dual S shaped micro strip antenna with a realistic feed is proposed for generation of tilted beam radiation pattern pertaining for beam steering applications. To achieve this, four feeding points are located at a distance of 5.6 mm from the antenna centre. These feeding points when excited one by one generate four tilted beams in four different space quadrants, thus yielding a beam steerable antenna. Importantly, since the proposed antenna is symmetrical in the structure, all the four tilted beams have the same radiation pattern characteristics. A further enhancement of the antenna bandwidth is also achieved using 100-μm capacitive coupling between the feed and the antenna strip.     

利用Matlab对梁内力进行自动处理

本文利用Matlab语言,结合奇异函数对工程设计中常见梁的内力进行计算机自动处理,并直接画出剪力图和弯距图。     

一种改进的全局优化进化算法

提出了一种改进的全局优化进化算法.该算法采用实数编码,通过对可行域量子化用正交设计产生初始种群,用正交设计和因素分析设计杂交算子.在进行杂交之前,根据两个个体变量之间的距离恰当地应用高斯变异,平衡了算法的局部搜索能力和全局搜索能力,从而提高了算法的效率.最后的数值结果显示了该算法的有效性.     

钢结构焊接H形和箱形截面压弯构件的简化设计法

对钢结构焊接 Ｈ 形和箱形截面压弯构件，给出了采用等效轴心受压荷载进行截面设计的简化方法⒚该方法应用非常方便，计算量远小于通常采用的反复试算法，设计效率高且质量较优，可供工程技术人员参考使用⒚     

波导DCN激光器输出特性的理论和实验分析

介绍了波导DCN激光器的原理和结构,重点研究了波导DCN激光本征模(EH11模)在远场和近场的多阶高斯耦合效应,分析了DCN激光器的输出特性.理论计算的结果与实验数据基本吻合,并为EAST托卡马克远红外激光干涉仪系统的光学设计提供了必要条件     

基于不确定性理论的彩色图像多阈值分割

提出一种新的彩色图像多阈值分割算法,首先根据点关联度的仿射性和仿射变换的保序性对色彩空间进行特征组合;再对组合后的灰度图像统计其信息熵,然后对信息熵进行模糊隶属划分。实验表明:在图像色彩信息较为丰富的情况下,该方法能够对RGB彩色图像中的基色和非基色进行有效划分。     

静电场中的高斯定理及其应用

高斯定理在静电学中的重要性 ,用高斯定理求电场强度注意的问题 ,取高斯面的原则及高斯面上的电场强度与空间电荷的关系。     

基于维纳滤波的高斯含噪图像去噪

分析了几种常见的图像去噪方法的去噪原理和缺点后,主要研究了维纳滤波算法的去噪原理和其在实际应用中对高斯噪声的去除优点,通过实验对比维纳滤波算法和其他几种常见的图像去噪方法对高斯噪声的去噪效果,并分析不同参数对维纳滤波去噪效果的影响.实验结果表明,综合主观视觉效果和客观PSNR值而言,在去除高斯噪声时,维纳滤波可以取得更好的去噪效果,提高所获取图像的质量.