钢烟囱的检测鉴定

本文通过对钢烟囱明显晃动的情况检测,分析和进一步探讨其产生的原因,并提出了相应的解决办法.     

索穹顶结构自振特性有限元分析

建立了索穹顶结构非线性动力特性分析的有限元模型 ,首先分析了索穹顶结构的自振特性 ,弄清楚各阶频率及对应的振型 ,然后进行参数分析 ,主要从索元预应力、单元截面积等参数变化来比较 ,得出这些参数变化对结构频率的影响 ,从而得出一些有益于结构设计的结论     

Stability criteria for rectangular plates subjected to intermediate and end inplane loads

This paper is concerned with the elastic buckling of rectangular plates subjected to intermediate and end uniaxial inplane loads, whose direction is parallel to two simply supported edges. The aforementioned buckling problem is solved by decomposing the plate into two subplates at the location where the intermediate uniaxial load acts. Each subplate buckling problem is solved exactly using the Levy approach and the two solutions brought together by matching the continuity equations at the separated interface. It is worth noting that there are five possible solutions for each subplate and consequently there are 25 combinations of solutions to be considered. For different boundary conditions, the buckling solutions comprise of different combinations. For each boundary condition, the correct solution combination depends on the ratio of the intermediate load to the end load. The exact stability criteria, presented both in tabulated and in graphical forms, should be useful for engineers designing walls or plates that have to support intermediate floors/loads.     

连续梁桥上部结构位移零点的确定

以一座装配式预应力混凝土先简支后连续小箱梁桥为例,对连续梁桥上部结构位移零点的含意,具体计算确定进行了分析计算,并阐述了上部结构位移零点对桥墩水平力、伸缩缝设计的影响,对于下部墩台结构的设计、伸缩缝的选择均有重要的意义。     

变频器数字语音设计

随着电子元器件以及控制技术的发展．变频器的性能越来越高．人性化的设计要求变得越来越突出。美国信息存贮器件公司的ISD1420单片语音录放芯片．以其优良的性能正被广泛应用。本文即是针对变频器人性化设计的要求．采用ATmega16L单片机控制．利用ID1420语音芯片，实现了变频器高性能语音提示的功能。     

Kinetic model of 4-CP degradation by Fenton/O2 system

A kinetic model of the degradation of 4-CP by Fenton/O(2) system was established, in which particular attention was paid to the role of oxygen in the process because many former researches suggested that the presence of oxygen could decrease the input of H(2)O(2). The proposed model well predicted 4-CP degradation and H(2)O(2) consumption by Fenton/O(2) and Fenton/N(2) systems at varying levels of Fe(2+), H(2)O(2), and 4-CP input. Most correlation coefficients between experimental and predicted data of 4-CP and H(2)O(2) concentration were above 0.95. The model could predict the enhancement of 4-CP degradation by oxygen and the difference in the evolution of aromatic intermediates between Fenton/O(2) and Fenton/N(2) system. The predicted and experimental data both showed the degree of benzene ring cleavage in Fenton/O(2) system was higher than that in Fenton/N(2) system. Understanding the role of oxygen is very important to improve the decomposition performance.     

渗流场的差分法与防渗结构侧水压力的探讨

为解释常用的防渗体侧水压力计算模型与实测值之间的明显差异,文章提出：“节点间等效渗透系数”、“拓展零渗透节点”、“可变零渗透节点”等概念在分析地下水渗流场中的意义,以解决差分法对地下水渗流潜水面的数值模拟问题;并在模拟工程实例的基础上,对侧水压力实测的模拟结果和对常用防渗模型误差来源的分析;指出常用防渗模型侧水压力的分析误差主要是因该模型未能较准确反映实际流场而造成的;在工程应用中,防渗体侧水压力的确定应根据不同情况予以分别对待。     

施工现场正确实施三相五线制的意义

针对施工现场临时用电存在的误区，从理论上阐述了三相五线制约重要性、必要性，并就如何正确实施三相五线制进行分析，保障了施工用电的安全性。     

三岸桥吊杆结构研制

介绍广西三岸邕江大桥吊杆结构的研制，着重介绍大桥拱边特殊吊杆的结构型式即在原吊杆的基础上增加偏转矫正装置及其作用。