航摄相机畸变测量仪编码器分度误差测量中同轴度误差的测量方法

分析了航摄相机畸变测量仪编码器分度误差测最中同轴度误差测量与常规同轴度误差测量的不同点.针对航摄相机畸变测量仪旋转臂无法整周同转的情况,归纳出编码器回转轴与棱体几何中心同轴度误差的数学模型,推导出同轴度误差的计算公式,并通过实际测量较好地验证了数学模型,最终实现了对航摄相机畸变测量仪的校准.     

高精度天线测试台结构研究与分析

介绍了在微波暗室里进行天线精度测量的基本原理，从结构受最大载荷变形后对天线测试台精度的影响这一角度出发，给出了结构参数和变形与整体刚度之间的关系。同时对结构刚度进行详细分析，提出以系统重量最低和比刚度最高的加权因子法的多目标优化函数及优化策略，最后，在研究与分析的基础上，对高精度天线测试台结构特点进行了总结。     

摄象机参数高精度求解方法

提出了一种新的高精度的摄象机参数的求解方法，文章利用透视变换理论建立了摄象机数学模型，模型中考虑了摄象机镜头的径向畸变和切向畸变，首先利用牛顿－高斯非线性搜索方法求争摄象机畸变系数和一个中间矩阵，然后再从中间矩阵中分离出其它模型参数；     

会计信息失真原因及防范

虚假的会计信息,将严重扭曲股票的价值,扰乱资本市场秩序,侵害投资者的利益。笔者就会计信息失真的原因进行了分析,并就如何防范进行了探讨。     

Image compression using polylines

This paper describes a simple method of image compression based on representing the grey level variations across the rows of an image using polylines. Data compression is achieved because only the x-coordinates (or the difference in x-coordinates) and the grey levels of points at the ends of the line segments that make up the polylines are stored, rather than the grey levels of all the pixels. The operational structure of the method lends itself readily to parallel processing to achieve compression in real time. Experimental results obtained from the analysis of retinal and various other images indicate unnoticeable distortion and a reduction in the amount of image data to be stored by 66% on average.     

古塔变形数据分析

本文对古塔先后于1986年7月、1996年8月、2009年3月和2011年3月的4次观测数据进行分析,通过倾斜、弯曲、扭曲等方面进行变形定量描述,以制定必要的保护措施。     

Hierarchical Laplacian-based compression of triangle meshes

In this paper, we present an algorithm for efficient encoding of triangle meshes. The algorithm preserves the local relations between vertices by encoding their Laplacian coordinates, while at the same time, it uses a hierarchy of additional vertex constraints that provides global rigidity and low absolute error, even for large meshes. Our scheme outperforms traversal based as well as Laplacian-based compression schemes in terms of both absolute and perceived distortion at a given data rate.     

基于Design-Expert V7设计的不锈钢激光非熔透搭接焊工艺优化研究

在保证焊接接头的力学性能的前提下,采用Design-Expert V7软件对厚度为0.8 mm/1.5 mm的SUS301L奥氏体不锈钢激光搭接焊接试验进行设计,并通过优化焊接参数来减少焊缝背面微凸变形。为了获得最佳的激光焊接工艺参数,建立一套与每个焊缝特征相关的焊接参数的数学模型。并通过验证试验检验所建立的数学模型的准确性,其误差范围小于5%,可以被用于后续的优化分析。根据优化方案得到最佳的焊接条件是激光功率、焊接速度、激光入射角度和离焦量分别为3.50～3.79 kW、7.40～8.00 m/min、65°和0 mm。同时,通过试验研究和优化分析得出,离焦量只对最优区域的偏移有影响,对最优区域的宽度影响不大,而激光入射角度对最优区域的偏移和宽度均有较大影响。     

Blind Separation of rotating machine signals using Penalized Mutual Information criterion and Minimal Distortion Principle

The Blind Separation problem of convolutive mixtures is addressed in this paper. We have developed a new algorithm based on a penalized mutual information criterion recently introduced in [El Rhabi et al., A penalized mutual information criterion for blind separation of convolutive mixtures, Signal Processing 84 (2004) 1979–1984] and which also allows to choose an optimal separator among an infinite number of valid separators that can extract the source signals in a certain sense according to the Minimal Distortion Principle. So, the minimisation of this criterion is easily done using a direct gradient approach without constraint on the displacements. Thus, our approach allows to restore directly the contribution of the sources to the sensor signals without post-processing as it is usually done. Finally, we illustrate the performances of our algorithm through simulations and on real rotating machine vibration signals.     

Electrocatalytic activity of amorphous RuO2 electrode for oxygen evolution in an aqueous solution

The electrocatalytic activity of amorphous and crystalline RuO₂ thin films for oxygen evolution in an aqueous solution was investigated. The RuO₂ films were prepared on FTO substrates by electrodeposition or RF magnetron sputtering technique. The obtained films were annealed at various temperatures. In both cases, the as-prepared films or the 200 °C annealed film had an amorphous structure, whereas the films annealed at 300 °C and over were crystallized to rutile structure. The analysis of the Tafel slope indicated that the rate-determining step in the oxygen evolution reaction on the amorphous RuO₂ was the combination of the adjacent Ru–OH groups, whereas that on crystalline RuO₂ was the dissociation of O–H bond in Ru–OH group. The onset potentials of the amorphous RuO₂ films for oxygen evolution were shifted toward the negative side by 0.06–0.03 V from those for the rutile crystalline samples. The shift of the onset potential is probably attributed to the structural flexibility which is characteristic of the amorphous surface. This result suggested that the electrocatalytic activity of amorphous RuO₂ for oxygen evolution was higher than that of rutile crystalline RuO₂.