变电站谐波测试和分析

对选定回路进行谐波测试,分析变流设备产生谐波的原因,并提出抑制方案.     

一种基于模板和DCT变换的柔性电路板配准方法

针对柔性印刷电路板（FPC）生产检测过程中的效率、精度等要求,提出一种基于模板与离散余弦变换（DCT）描述子的配准方法。首先,为了解决配准的精度问题,由电路板文件工程图解析得到对应图像,为后续处理提供更好的模板图,再利用离散余弦描述子的频域能量聚集特点,在模板与被检测图像之间建立对应关系,从而计算出对齐参数。其次,使用mipmap技术处理模板,为配准阶段提供不同精度的模板图片,从而有助于精度及效率的提升。实验结果表明：该改进算法的最大误差和平均误差均比原方法小;对于电路板这种大分辨率的图像,在mipmap采样的模板条件下,可以获得较高的精度,且处理速度有较大的提升。     

Fabrication and thermal performance of grooved-sintered wick heat pipe简

Some novel grooved-sintered composite wick heat pipes（GSHP） were developed for the electronic device cooling.The grooved-sintered wicks of GSHP were fabricated by the processes of oil-filled high-speed spin forming and solid state sintering.The wick could be divided into two parts for liquid capillary pumping flow：groove sintered zone and uniform sintered zone.Both of the thermal resistance network model and the maximum heat transfer capability model of GSHP were built.Compared with the theoretical values,the heat transfer limit and thermal resistance of GSHP were measured from three aspects：copper powder size,wick thickness and number of micro grooves.The results show that the wick thickness has the greatest effect on the thermal resistance of GSHP while the copper powder size has the most important influence on the heat transfer limit.Given certain copper powder size and wick thickness,the thermal resistance of GSHP can be the lowest when micro-groove number is about 55.     

Letter: Solution‐processed flexible zinc‐tin oxide thin‐film transistors on ultra‐thin polyimide substrates

In this letter, solution‐processed flexible zinc‐tin oxide (Z_0.35T_0.65O_1.7) thin‐film transistors with electrochemically oxidized gate insulators (AlOx:Nd) fabricated on ultra‐thin (30 µm) polyimide substrates are presented. The AlOx:Nd insulators exhibited wonderful stability under bending and excellent insulating properties with low leakage current, high dielectric constant, and high breakdown field. The device exhibited a mobility of 3.9 cm²/V · s after annealing at 300 °C. In addition, the flexible device was able to maintain the electricity performance under various degrees of bending, which was attributed to the ultra‐thin polyimide substrate.     

Design of a printed log‐periodic dipole array antenna with high gain for millimeter‐wave applications

In this article, a V‐band printed log‐periodic dipole array (PLPDA) antenna with high gain is proposed. The antenna prototype is designed, simulated, fabricated, and tested. Simulation results show that this antenna can operate from 42 to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V‐band (50–75 GHz). The antenna has a measured impedance matching bandwidth that starts from 42 to beyond 65 GHz with good agreement between the experimental and simulated results. At 50 and 65 GHz, the antenna has a measured gain of 10.45 and 10.28 dBi, respectively, with a gain variation of 2.6 dBi across the measured frequency range. The antenna prototype exhibits also stable radiation patterns over the operating band. It achieves side‐lobe suppression better than 17.26 dB in the H‐plane and better than 8.95 dB in the E‐plane, respectively. In addition, the cross‐polarization component is 18.5 dB lower than the copolarization with front‐to‐back ratio lower than 24.1 dB in both E‐ and H‐planes across the desired frequency range. Based on a comparison of performance among the reported work in the literature, we can say that the proposed PLPDA antenna is a proper candidate to be used in many applications at V‐band frequency. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:185–193, 2015.     

“电力电子技术”课程教学改革与实践

为了克服目前"电力电子技术"课程在"教"与"学"环节上存在的不足与缺陷,本文从教学理念、教学方法及手段、学习及实践能力培养等多个方面给出了相关教学改革的思路及措施;实践表明,该教学改革不仅能提高"电力电子技术"课程的教学效果,还能很好地培养学生自主学习、实践操作及创新能力。     

打印信息防伪认证的一种逻辑签署技术及应用

为了防范对打印信息的伪造、篡改及非法使用,提出了一种逻辑签署技术,设计并实现了基于该技术的防伪认证系统,通过完整的逻辑体系保证其密码学意义上的高安全性,使得打印信息的检验过程快速、便利、精准和实用。该系统是一个开放的不受具体物理设备限制的体系,突破了现有打印信息防伪认证技术的模式。     

浅谈硬盘保护机房中几种电子作业存储方法

目前学校公共机房的计算机,为了防止学生对系统的有意或无意的破坏,减少病毒对电脑的破坏,通常采用软件或硬件对硬盘数据进行保护,这是很有必要的,随之就带来了一个问题:一些连续性比较强的项目学习,以及平时的随堂练习中,学生需要保存一些文件,如何解决。笔者在日常机房管理中尝试了多种方法,该文将谈谈各种方法,以供大家参考。     

车用工具套件的构件化设计与实现

实现了一个针对测量、标定和诊断功能的构件化车用工具套件系统.通过分析汽车行业中嵌入式开发对工具可移植性和扩展性的需求,结合对匹配标定规范ASAP和开源构件化工具Eclipsc的讨论,从时构件技术封装方式和Java平台元编程、反射API及JNI技术的研究入手,提出了一个资源控制模型和与其对应的配置模型,并设计了一个采用锁分离技术和观察器模式的消息队列模型,满足了系统的效率,灵活性以及同领域标准兼容性的要求,并通过试验环境下的运行证明了系统的有效性.     

“电力电子技术”课程实践教学改革探讨

从课程实验、课程设计、实践创新训练和计算机仿真等几个方面,探讨了如何提高电力电子技术课程实践教学的教学质量,促进学生实践能力的提高和创新精神的培养。教学改革取得了较好的效果。