二维指向镜的成像特性分析

目标搜索和跟踪一体化的光电探测系统常采用二维指向镜与面阵凝视成像探测相结合的技术方案.本文在光学矢量反射理论的基础上,对二维指向镜的成像特性进行了分析,给出了扫描轨迹的计算,指向镜摆动角度与视线角之间的关系.当指向镜绕两轴转动时,物体反射像也随着指向镜的转动产生像旋,扫描轨迹呈非线性变化.文中讨论了多元探测器像旋角的计算和对跟踪系统的影响,为软件校正像旋和二维控制实现精确跟踪提供理论参考价值.     

基于脊波变换的旋转不变性纹理特征提取方法

提出了一种新的基于脊波变换的旋转不变性纹理特征提取方法。该方法是先在脊波变换过程中的一维小波变换后所形成的每个频率子波段中提取特征,然后采用构建直方图的方法来提取同一尺度下高、低频子波段之间的关系特征,最后将这些特征进行一维傅里叶变换后取幅值并进行特征级融合,从而得到旋转不变性纹理特征。实验结果表明所提出的方法与两种已有的方法相比能够取得更好的分类效果。     

Structure and properties of high power impulse magnetron sputtering and DC magnetron sputtering CrN and TiN films deposited in an industrial scale unit

Deposition of complex shaped or round-symmetric samples requires multi-fold substrate rotations during deposition or multiple cathode arrangements. The present paper investigates the influence of the high power impulse magnetron sputtering (HIPIMS) and DC magnetron sputtering (DCMS) process on the mechanical and tribological properties as well as the resulting structure of CrN and TiN coatings using static (0-fold) and dynamic (1-, 2- and 3-fold) depositions in an industrial scale unit. Furthermore, to increase the deposition rate without losing the high ion density in the plasma a hybrid HIPIMS/DCMS deposition technique is investigated. The results demonstrate the advantage of the HIPIMS technique when using multi-fold substrate rotation during deposition as it enables depositions of CrN_HIPIMS and TiN_HIPIMS coatings with hardness values around 23 and 35 GPa, respectively, compared with around 15 GPa for CrN_DCMS and TiN_DCMS coatings. Hardness values of 35 GPa for TiN_DCMS coatings prepared with substrate rotations could only be obtained when introducing an additional anode or using a multilayered CrN_HIPIMS/TiN_DCMS base layer as a template.Based on our results we can conclude that especially for up-scaling and multi-fold substrate rotations the HIPIMS process offers an improved performance as compared to DCMS.     

旋转机械故障诊断的神经网络方法研究

BP神经网络具有较好的非线性映射能力,可以描述频率特征和故障之间的关系,而概率神经网络学习规则简单、训练速度快、避免局部极小和反复训练的问题。根据两种神经网络的原理选择合适的参数建立两个旋转机械故障诊断模型,并利用模型对某旋转机械的故障数据进行处理,结果显示两种网络在故障诊断方面的实用价值。通过对故障数据的结果对比可以看到PNN网络比BP网络具有更好的容错能力。     

Generation of a pressure–impulse diagram for a temporary soil wall using an analytical rigid-body rotation model

This study aimed to provide a simple and efficient model to calculate a time history of response and construct a pressure–impulse (P–I) iso-damage curve for a free-standing soil-filled HESCO Bastion (HB) concertainer^® wall subjected to blast loading based on the maximum rotation of the wall. An analytical model is formulated for a free-standing HB simple straight wall based on rigid-body rotation. The maximum rotations observed in a full-scale blast testing of free-standing simple straight walls were compared with the maximum rotations calculated using the proposed analytical model and are in good agreement. The model is subsequently used to calculate a P–I curve for the wall, which is a common iso-damage curve used in a blast-resistant design, and represents various combinations of blast pressures and impulses required to damage the wall to a selected failure criterion. The failure criterion was selected as the critical amount of rotation required to completely overturn the wall. The resulting P–I curve was plotted along with the different charge performance curves or the pressures and impulses of different charge sizes. The curves show that the overturning of the HB walls, except for extremely large charge sizes, is governed by the amount of blast impulse and not the blast peak pressures. This indicates that the response of HB walls is impulse dominated. The effect that material density has on P–I curves was studied and found to be relatively insignificant. The P–I curves calculated based on different degrees of rotation as failure criteria were also plotted and compared. The curves showed that the required blast impulse to rotate the wall to 75% of the complete overturning angle and the required blast impulse to completely overturn the wall were very close. This illustrates that the magnitude of rotation becomes increasingly sensitive to blast impulse as blast impulse approaches the critical blast impulse required to completely overturn the wall.     

μSR技术与穆斯堡尔谱学

本文对近年来发展起来的μSR技术(μ子自旋转动)进行了介绍,并与穆斯堡尔谱学进行了比较,最后讨论了μSR技术在磁学中关于内磁场的测量和自旋动力学方面的研究应用。     

点阵图形的高效旋转算法

本文给出一种速度快、效果好的点阵图形（如汉字）旋转算法。     

An investigation of the characteristics of the stationary feed motor current in NC machines

The cross-feed directional cutting force acts normal to the machined surface of a workpiece. It is important to estimate and control this force, since it directly affects the machined surface. However, using the current supplied to a stationary motor to predict the cutting state poses difficulties, because of the current's somewhat undesired behaviour. In this paper, a largely empirical approach was used to help resolve this problem. We show that the current's undesired behaviour is related to infinitesimal rotations of the motor. Subsequently, the relationship between the current and the cutting force was identified with an error of less than 15%. The predictions obtained using two machine tools with different characteristics were compared to confirm the validity of the method when investigating the characteristics of the stationary feed motor current.     

Analysis of three-dimensional rotation and linear shape changes

A relationship between 3D rotation of an object and 2D shape changes in a sequence of images is established. It is shown that with orthographic projections, the 3D rotation angles can be computed from a set of linear shape change parameters.     

秦山核电厂反应堆压力容器水压试验应变测量与分析

对秦山核电厂反应堆压力容器出厂水压试验测点布置作了说明,与一回路系统水压试验位移测量的主要结果作了分析对比,给出了实测载荷与主螺栓测试数据,讨论了表征密封性能的法兰转动,认为出厂水压试验此项结果有错.