锥形图形衬底上氮化镓薄膜生长和表征

GaN films are grown on cone-shaped patterned sapphire substrates(CPSSs)by metal-organic chemical vapor deposition,and the influence of the temperature during the middle stage of GaN growth on the threading dislocation(TD)density of GaN is investigated.High-resolution X-ray diffraction(XRD)and cathodeluminescence(CL)wereusedtocharacterizetheGaNfilms.TheXRDresultsshowedthattheedge-typedislocation density of GaN grown on CPSS is remarkably reduced compared to that of GaN grown on conventional sapphire substrates(CSSs).Furthermore,whenthegrowthtemperatureinthemiddlestageofGaNgrownonCPSSdecreases,the full width at half maximum of the asymmetry(102)plane of GaN is reduced.This reduction is attributed to the enhancement of vertical growth in the middle stage with a more triangular-like shape and the bending of TDs.The CL intensity spatial mapping results also showed the superior optical properties of GaN grown on CPSS to those of GaN on CSS,and that the density of dark spots of GaN grown on CPSS induced by nonradiative recombination is reduced when the growth temperature in the middle stage decreases.     

浏览器跨域通信安全技术研究

浏览器作为互联网的重要入口,处理服务器返回的超文本信息和各种多媒体数据。这些数据信息可能来自不同的Web系统,其间,数据通信的处理方式随着时间推移和技术的发展也在不断发展变化。不同类别浏览器、不同测试环境、不同脚本语言下,其表现结果也有所不同。首先对浏览器同源策略的基本原理和跨域技术特点进行综述,然后总结归纳了主流跨域通信的技术实现方法,最后针对主流跨域通信的方法进行了安全分析。通过跨域通信来解决资源共享,身份认证,数据交换等安全的现实问题。     

Optimization Design of Muti-Band Wilkinson Power Divider by the Method of Genetic Algorithm

Design of multi-band Wilkinson power dividers using genetic algorithm are proposed. Based on the ideal transmission line model and the concept of the even-odd modes analysis, the design equations of the multi-band equal-power split WPD with the multi-section transmission line and their corresponding isolation resistances are given. The optimal solutions are obtained via the process of the genetic algorithm optimization. Some numerical examples of the dual-band, tri-band and quad-band Wilkinson power divider are presented to verify the proposed design method.     

跟踪式光伏发电系统的性能分析

对不同太阳位置的表述方法进行了简单描述,详细讨论了光伏跟踪系统的分类.基于处理过的PSA算法及向量法对太阳位置进行计算,计算出的太阳位置与MICA数据对比误差在0.7°以内.给出更有利于跟踪系统应用的准赤道坐标系统,从朗伯余弦定理出发,给出单轴倾斜轴跟踪系统的最佳跟踪角度vs计算公式,并且给出了具有方位角、坡度校正的vso以R.Perez模型为基础,结合PSA算法以及向量法等对不同地区、不同结构的跟踪系统的性能进行对比分析,vs角跟踪的优势得到了论证.     

Numerical investigation on spectral compression of femtosecond soliton in a dispersion-increasing fiber

The spectral compression performance of the fundamental soliton in a dispersion-increasing fiber is investigated through numerically solving the generalized nonlinear Schrödinger equation. Based on the calculation results, we detailedly analyze the influence of the input peak power, the fiber length, and the initial chirping on the output pulse, e.g. the spectral width, the spectral width ratio, and the center wavelength. The calculation results show that spectral compression from 12.6 nm to 5.2 nm, can be realized for the soliton with pulse width of 200 fs and center wavelength of 1550 nm propagating in the dispersion-increasing fiber with length of 100 m and the group-velocity dispersion parameter linearly varying from −1 ps²/km to −11 ps²/km.     

基于光谱干涉技术的玻璃厚度及折射率测量方法

基于光谱干涉技术提出了一种能够同时测量玻璃厚度及折射率的方法,该方法利用迈克尔逊光路,通过傅里叶变换算法对光谱仪接收的干涉信号进行解算,获取光谱干涉条纹的调制周期,根据待测玻璃样品放入测量臂前后,测量臂与参考臂所形成的光程差即可求出玻璃样品的几何厚度和折射率。该方法无需机械扫描延迟线并采用改进的傅里叶域下的相位提取算法,提高了测量系统抗干扰能力,探测速度快。实验结果表明:对玻璃样品的厚度测量精度优于±1μm,折射率测量精度±5×10^-4。     

平板显示器驱动电路技术分析

介绍了平板显示器件。如场发射显示器、等离子体显示器、液晶显示器、有机电致发光显示器驱动电路．分析了不同驱动电路的优点、缺点。     

基于PROFIBUS-DP总线的高压软起动器通信模块的开发

自动控制技术和计算机技术及电力电子技术的迅速发展,使开发具有PROFIBUS-DP技术的产品成为国内智能设备的一大热点。对基于PROFIBUS-DP技术的高压软起动器通信模块的开发进行阐述,高压软起动器作为智能从站参入PROFIBUS-DP总线中组态,高速、安全、可靠的通信说明了高压软起动器通信模块的开发是成功的。     

采用软交换技术实现MSC冗灾备份

本文通过对软交换技术架构、组网方式、话务信令路由等方面的分析,探讨如何采用软交换技术对传统移动交换端局进行冗灾备份.     

基于Verilog语言的等精度频率计设计

介绍了等精度测量频率的原理,利用Verilog硬件描述语言设计实现了频率计内部功能模块,对传统的等精度测量方法进行了改进,增加了测量脉冲宽度的功能;采用AT89S51单片机进行数据运算处理,利用液晶显示器对测量的频率、周期、占空比进行实时显示,可读性好.充分发挥FPGA(现场可编程门阵列)的高速数据采集能力和单片机的高效计算与控制能力,使两者有机地结合起来.在QuartusⅡ6.0 EDA(电子设计自动化)开发平台上进行仿真、测试,并最终下载到FPGA芯片内部.系统测量精度高,实时性好,具有很好的应用前景.