基于立体九域图的变电站无功电压控制策略研究

电压合格与无功充足是电力系统安全稳定运行的基础条件,确定适宜的无功补偿方法和电压调节方案对电网运行有着重要意义。提出了基于立体九域图的无功电压控制策略,与传统九域图控制策略相比,增加了时间轴,在不同的时间段(时区)九域图的无功功率上下限和电压上下限是变化的。通过基于负荷预测的全局无功优化模型得到配电网各变电站的预计调节方案,以此将一天划分为若干个时区,并根据优化曲线得到各时区的运行边界。基于立体九域图的变电站无功电压控制策略结合了动态无功优化与实时调控的优点,避免了无功补偿设备和主变分接头的频繁调节,提高了变电站运行的经济性。     

Experimental study of interband and intraband crosstalk in WDM networks

The impacts of interband and intraband erosstalk are studied and compared experimentally. Results show that interband crosstalk can be removed with narrow-band filters and has no influence on signal. Intraband crosstalk will result in signal eye diagram close and BER increasing. When the polarization states of signal and crosstalk align, intraband crosstalk seriously decreases signal quality. But when they misalign, it has little influence. Coherent and incoherent crosstalk are studied experimentally. Results show that coherent crosstalk is less harmful to system performance than incoherent crosstalk.     

基于多级维纳滤波对消的方向图综合

针对降低天线阵的副瓣电平和优化天线阵的方向性这一问题,在线性约束最小方差(LCMV)算法的基础上,引入了基于多级维纳对消的方向图综合算法。该算法充分考虑综合方向图和参考方向图之间的相对幅度对方向图综合的影响,通过多级维纳对消器输出的最优权值自适应地改变相对幅度,提高了干扰功率的迭代效率,降低了迭代的次数,同时又降低了综合方向图和参考方向图之间的综合误差。由于多级维纳对消器的引入,该算法具有较强的鲁棒性,拓展了方向图综合方法的应用范围和适用性。     

高速A/D转换器AD9481原理及应用

在采集速率要求高的场合,A/D转换器的性能起关键作用。AD9481是模拟器件公司的8位250 MHz采样率A/D转换器。介绍了AD9481的主要性能、引脚构成、内部结构、工作时序,提供了参考设计电路。最后给出了基于FPGA控制转换的原理框图。为基于AD9481的高速A/D转换电路设计提供了参考依据。     

相位图法研究光子晶体的禁带

给出了一种判断一维光子晶体禁带位置的相位图,利用扩展相位图可方便地描述光子晶体的禁带位置和禁带特征.研究发现,当光子晶体为1/4波片层堆时,光子晶体的禁带最宽;若要进一步展宽禁带,需提高构成周期单元的两种介质的折射率比.对于一般的光子晶体,若周期单元中两种介质的光学厚度不等,则其禁带中心将偏离中心频率的整数倍.此外还研究了禁带中心区的透射率,给出了中心频率附近透射率的一级近似解析解,并由此定性讨论了Fabry-Perot腔的谱线宽度和品质因子.     

A Verification-Based Approach to Evaluate Software Architecture Evolution

As the development and wide usage of Soft-ware architecture (SA), SA evolution becomes one of the hotspots of current research in modern software engineer-ing domain. Most current researches concentrate on the modeling of SA evolution and lack the verification and evaluation of SA evolution. We proposed a verification-based approach to evaluate SA evolution. The basic pro-cess includes: 1) using Unified modeling language (UML) sequence diagram to model the interaction of components and study different types of evolution in practical ex-amples; 2) using SPIN-based model checking to model and verify SA evolution; 3) comparing various verifica-tion outcomes and analyzing the influence of SA evolution on SA correctness and temporal properties. Both theory analysis and an experiment on a real evolution example from Model-view controller (MVC) to Spring web MVC (SWMVC) show that the verification-based approach to evaluate SA is significant.     

“模拟电子电路”课程教学改革思考

本文就＂模拟电子电路＂课程教学中计算机辅助教学、授课安排以及实验教学三个方面的问题进行分析。我们提出使用3D电路图的方法增强学生对电路的感性认识,在授课安排中穿插介绍电子元器件基本知识以及使用范围,提升学生的工程意识;我们在＂模拟电子电路＂课程实验环节引入＂虚拟公司＂形式,以强调真实环境和真实压力,以问题为向导和任务为导向的方法有效地提高学生在电路设计中的自学意识、成本意识和在工作中的协同能力。     

电容式传声器腔体设计

介绍了电容式传声器的内部结构,通过等效线路图,详细说明了传声器内部腔体结构对声学性能的影响,最后说明了传声器实际组配过程中,机构件对传声器声学性能的影响。     

Impact of Ge-Sb-Te compound engineering on the set operation performance in phase-change memories

The phase-change memory (PCM) technology is considered as one of the most attractive non-volatile memory concepts for next generation data storage. It relies on the ability of a chalcogenide material belonging to the Ge-Sb-Te compound system to reversibly change its phase between two stable states, namely the poly-crystalline low-resistive state and the amorphous high-resistive state, allowing the storage of the logical bit. A careful study of the phase-change material properties in terms of the set operation performance, the program window and the electrical switching parameters as a function of composition is very attractive in order to enlarge the possible PCM application spectrum. Concerning the set performance, a crystallization kinetics based interpretation of the observed behavior measured on different Ge-Sb-Te compounds is provided, allowing a physics-based comprehension of the reset-to-set transition.     

论QC七大手法之——层别法,要因图与戴明环的具体运用

现代企业非常重视管理,但只有将管理.改善.统计方法三者有机结合起来,互相连贯运用,才能在整体上发挥效果.本文结合实际,重点阐述层别法,要因图与戴明环(PDCA循环)相结合的应用,能很好的改善生产过程中出现的品质问题.