Levy-type solution for buckling analysis of orthotropic plates based on two variable refined plate theory

This paper presents closed-form solution for buckling analysis of orthotropic plates using two variable refined plate theory. The theory accounts for a quadratic variation of the transverse shear strains across the thickness, and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. Governing equations are derived from the principle of minimum total potential energy. The closed-form solutions of rectangular plates with two opposite edges simply supported and the other two edges having arbitrary boundary conditions are obtained by applying the state space approach to the Levy-type solution. Comparison studies are performed to verify the validity of the present results. The effects of boundary condition, loading condition, and variations of modulus ratio, aspect ratio, and thickness ratio on the critical buckling load of orthotropic plates are investigated and discussed in detail.     

变极性等离子弧焊铝合金厚板工艺研究

变极性等离子弧焊是一种新型焊接方法,由于等离子弧对焊接工艺和规范参数的变化比较敏感,获得良好焊缝接头的合理规范参数范围窄、裕度小.本文通过工艺试验,探讨了变极性等离子弧焊16mm铝合金厚板的技术可行性,论述了其相对于传统弧焊工艺的优点.     

非对称电阻场板场效应器件击穿特性仿真分析

利用TCAD仿真研究一种二维紧耦合电阻场板电流调制原理下的物理模型与最优化结构。通过优化关键工艺与材料参数,改善器件漂移区尖峰电场,最终在相同漂移区掺杂下击穿电压较一维PN结理论击穿电压提升273%,相同归一化击穿电压10%变化范围下,漂移区电荷变化允许冗余范围比现有传统PN超结拓宽15倍。相较于对称电阻场板场效应器件,在现有工艺下非对称优化电阻场板场效应器件能够更好的实现结构小型化与高密度的设计。     

限形压具在薄壁件锥盘中的应用

研究锥盘淬火变形的原因,改进设计限形淬火压具,使薄壁件锥盘的淬火变形报废率由25％下降到5％以下,经济效益和社会效益十分显著。     

Integrated Analysis of Microarray,Small RNA,and Degradome Datasets Uncovers the Role of MicroRNAs in Temperature-Sensitive Genic Male Sterility in Wheat

Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.     

利用偏光分束棱镜测定波片的延迟量

在文〔３〕的基础上,提出了波片延迟量测量精度较高的方法。     

传爆序列飞片起爆理论研究及应用

在考虑受主炸药盖片对撞击入射冲击波衰减作用的基础上，得到了改进的飞片起爆计算模型，经与实验结果对比表明这一改进模型更符合实际系统。     

基于改进BOF算法的压板状态识别方法研究

随着电网规模的扩张以及二次技术的发展,二次屏柜的压板数量急剧上升.二次压板一旦出现保护误动或拒动,将严重威胁到电网、设备与人身安全.设计了一种基于改进图像检索算法的继电保护压板状态识别系统对压板退投状态进行识别.首先,对压板图像利用背景差分法及光流法进行前景提取;然后,采用图片增强处理、边缘检测等一系列技术识别开关的投...     

2800mm中厚板轧机轧制力模型研究

在考虑温度场对轧制力能参数影响的条件下,利用ANSYS软件对热轧板带的塑性变形过程进行了力能参数的计算,并由此获得2800 mm轧机轧制压力的计算模型.经在武钢2800 mm轧机生产现场实测大量数据,进一步完善轧制力模型,使之具有良好的计算精度.     

The orthogonal meshless finite volume method for solving Euler–Bernoulli beam and thin plate problems

In this paper a new method untitled “orthogonal meshless finite volume method” (OMFVM) is developed for solving elastostatic problems in Euler–Bernoulli beam and thin plate. In this method, the weak formulation of a conservation law is discretized by restricting it to a discrete set of test functions. In contrast to the usual finite volume approach, the test functions are not taken as characteristic functions of the control volumes in a spatial grid, but are chosen from a Heaviside step function. The present approach eliminates the expensive process of directly differentiating the OMLS interpolations in the entire domain. This method was evaluated by applying the formulation to a variety of patch test and thin beam problems. The formulation successfully reproduced exact solutions. Numerical examples demonstrate the advantages of the present methods: (i) lower-order polynomial basis can be used in the OMLS interpolations; (ii) smaller support sizes can be used in the OMFVM approach; and (iii) higher accuracies and computational efficiencies are obtained.