GE发变组保护二次接线及逻辑设计的分析与改进

华能玉环电厂自2007年4台机组相继投产以来,在GE发变组保护二次回路接线设计及GE发变组程序逻辑设置方面存在较多问题。对发变组保护启动厂用电快切、线路断面零功率切机、发电机过激磁保护二次回路接线及逻辑设计存在的问题进行分析和改进,使发变组保护功能更加完善,有力地保证了电力系统的安全生产。     

补丁分发与管理系统的设计和实现

近年来不断出现的漏洞导致信息系统经常受到各种攻击和威胁,大部分攻击是因为没有及时安装补丁造成的。文章针对目前补丁管理存在的一些问题,提出了一套补丁分发与管理系统。该系统可控性和可管理性好,提供补丁适用性测试,支持多种组网方案的扩充。实验表明,该系统可以及时跟踪补丁更新,并实施有效部署,确保补丁被及时有效地安装。     

润滑油漆膜的成因及其消除方法

文章介绍了润滑油漆膜的定义和形成过程,以及通过对润滑油漆膜形成过程的分析,得出影响漆膜形成的因素,以及润滑油的溶解性对漆膜形成过程的影响。利用动态平衡过程,解释漆膜形成过程的模型图,通过薄膜比色法预测漆膜的形成倾向性。最后,介绍了两种常用的漆膜消除方法,包括过滤法与离子树脂法。     

划分特征子区域的图像修复算法

为了解决含有丰富纹理信息和复杂结构信息的大破损区域中的缺失信息修复的问题,提出了一种划分特征子区域的图像修复算法。首先,根据图像中包含的不同特征,运用特征公式进行特征提取,再通过统计特征值划分特征子区域,提高了图像修复的速度;其次,在原Criminisi算法的基础上改进了优先级的计算,通过增大结构项的影响,避免结构断裂的产生;然后,通过目标块和其最佳邻域相似块共同约束样本块的选取,确定最佳样本块集;最后,利用权值分配法合成最佳样本块。实验结果表明,所提算法相比原Criminisi算法,其峰值信噪比（PSNR）提升了2~3 dB,相比基于稀疏表示的块优先权值计算的算法,其修复效率有明显的提高。所提算法不但适用于一般小尺度的破损图像的修复,而且对于含有丰富纹理信息和复杂结构信息的大破损图像的修复效果也更佳,并且修复后的图像更加符合人们视觉上的连通性。     

线缆虚拟装配关键技术研究现状及其发展

线缆布线与安装是复杂机电产品设计中带有普遍性的难题,线缆的敷设质量已成为衡量产品整机性能和可靠性的一个重要指标。介绍了线缆虚拟装配的内涵和主要研究内容,重点对线缆虚拟装配涉及到的关键技术及其特点进行了分析,对比分析了国内外线缆虚拟装配的研究现状,分析和指出了线缆虚拟装配存在的问题以及发展趋势。最后对增强现实技术在线缆装配领域中的应用进行了展望。     

PCB排板布局焊盘及导线的可制造性设计

电子产品PCB Layout 需注意可制造性。器件的排板布局、焊盘及导线的合理设计是其可制造性的基本要求。文中总结了实际生产中的经验,论述了PCB Layout过程中排板布局、焊盘及导线的设计原则、要求和方法。基本的可制造性设计是产品生产高效率、高质量和低成本的关键,而把可制造性与高等教育的PCB设计教学紧密结合具有重要现实意义。     

一种贴片阵列天线散射减缩的新技术

引入贴片天线单元渐变开槽的方式来设计低散射阵列天线.通过对不同的单元开不同尺寸的槽,在等幅度馈电的情况下实现远区辐射场的低副瓣特性.对开槽贴片单元进行散射减缩预估,然后将该方法应用于1×9渐变开槽贴片阵列的设计中,与传统阵列天线的单元形式完全一样,采用不等幅馈电实现泰勒远区辐射场相比,该方法不仅实现了远区辐射场的低副瓣,而且实现了天线模式项散射场的低副瓣,同时又兼顾了结构模式项散射场的散射减缩,从而有效地实现了阵列天线的低散射特性.测量结果与原始阵列进行比较,证明了该方法的有效性.     

PKG‐VUL: Security Vulnerability Evaluation and Patch Framework for Package‐Based Systems

In information security and network management, attacks based on vulnerabilities have grown in importance. Malicious attackers break into hosts using a variety of techniques. The most common method is to exploit known vulnerabilities. Although patches have long been available for vulnerabilities, system administrators have generally been reluctant to patch their hosts immediately because they perceive the patches to be annoying and complex. To solve these problems, we propose a security vulnerability evaluation and patch framework called PKG‐VUL, which evaluates the software installed on hosts to decide whether the hosts are vulnerable and then applies patches to vulnerable hosts. All these operations are accomplished by the widely used simple network management protocol (SNMP). Therefore, system administrators can easily manage their vulnerable hosts through PKG‐VUL included in the SNMP‐based network management systems as a module. The evaluation results demonstrate the applicability of PKG‐VUL and its performance in terms of devised criteria.     

Rectangular Microstirp Patch Antenna Design at THz Frequency for Short Distance Wireless Communication Systems

In this paper, we have presented the simulation results of a rectangular microstrip patch antenna at terahertz (THz) frequency ranging from 0.7 to 0.85 THz. THz electromagnetic wave can permit more densely packed communication links with increased security of communication transmission. The simulated results such as gain, radiation efficiency and 10 dB impedance bandwidth of rectangular microstrip patch antenna at THz frequencies without shorting post configuration are 3.497 dB, 55.71% and 17.76%, respectively, whereas with shorting post configuration, corresponding parameters are 3.502 dB, 55.88% and 17.27%. The simulation has been performed by using CST Microwave Studio, which is a commercially available electromagnetic simulator based on the method of finite difference time domain technique.     

A novel wide-band circular patch antenna

In order to overcome the narrow-bandwidth of the patch antenna, one kind of configuration which can widen the bandwidth significantly is discussed in this letter. Analyzed by the equivalent-circuits method and simulated by HFSS, a rule derived from simulated results that can aid to design the microstrip antennas is found. Finally, the structure parameters are optimized out, which reaches 44.67% impedance bandwidth. Furthermore, this kind of configuration can also be applied to the multi-layer patch antenna.