工资邮件程序-为ERP提供完美支撑

本文主要对工资邮件程序的开发进行了分析介绍。首先介绍了本项目开发的背景,其次介绍了本项目的开发环境,最后详细介绍了ESMTP协议和EXCEL类库。     

SNC保护在故障测试定位中的应用

通过实例详细介绍了如何利用SNC保护测试来定位故障。文章首先介绍了具体实例的故障现象,接着介绍了测试方案和实施方法,然后着重介绍了测试过程。     

基于M600的便携终端显示界面设计

文章首先介绍了便携终端的组成和功能,然后介绍了北京迪文科技有限公司的M600人机界面驱动模组,接着介绍了便携终端显示模块的硬件构成,最后介绍了便携终端的显示界面设计。     

美国三大核武器实验室IT进展

简要介绍了美国三大核武器实验室近期IT基础设施的建设情况。首先对ESNet的主干网和涉密网SecureNet的建设和升级进行了介绍,并以LANL为例介绍了内部局域网的安全域划分;其次是对IT基础服务的介绍,并以SNL为例,介绍了其近年来的主要工作进展。     

MMT技术概述和基于MMT的混合媒体传输

本文介绍了MPEG近期推出了一项新的标准,MPEG Media Transport (MMT),介绍了它所包含的关键要素,同时介绍了MMT功能区、接口以及端到端构架.并对混合媒体在异构网络中的传输做了案例分析,对于时钟同步方式做了介绍.     

数字集群越区切换的研究(上)

本文介绍了数字集群中越区切换的相关知识和实现方法.首先,介绍了越区切换的产生原因.然后,介绍了越区切换的典型实现方法.接着,以TETRA系统为例着重介绍了数字集群中越区切换的实现过程.包括切换前的测量、切换的策略和如何切换处理.最后介绍了越区切换的考核方法.     

基于现网的HSPA＋网络部署探讨

介绍了HSPA＋的演进,并结合珠海外场测试介绍了系统如何升级HSPA＋网络,同时简要介绍了测试结果,最终提出64QAM部署建议     

TD-SCDMA/GSM/GRPS双模终端发展分析

首先介绍了双模终端的分类,然后介绍了双模终端的发展策略,最后重点介绍了双模终端在3G网络建设中的作用.     

ZigBee技术简介

首先介绍了ZigBee技术的由来．接着介绍了ZigBee协议栈的组成、网络拓扑、特点以及ZigBee技术的优点．最后介绍了ZigBee技术的应用。     

TD-SCDMA/GSM/GPRS双模终端发展分析

首先介绍了双模终端的分类,然后介绍了双模终端的发展策略,最后重点介绍了双模终端在3G网络建设中的作用。     

GaN基和GaAs基半导体激光器的电学特性研究

介绍了一种能够全面表征半导体二极管器件的电学特性的方法,此方法结合半导体二极管的正向交流特性和直流特性,称之为正向交流小信号法。利用该方法深入地研究和对比分析了GaN基和GaAs基半导体激光器的电学特性,包括表观电容、串联电阻和理想因子。实验结果表明,对于GaN基和GaAs基半导体激光器,其开始发光的过程同步于其电容由正转变为负的过程。进一步实验结果表明,GaN基半导体激光器比GaAs基半导体激光器具有更大的串联电阻和更大的理想因子。这是由于GaN基激光器的器件工艺不够完善以及外延生长的GaN材料具有很大的位错密度。该研究为提高和改善GaN基激光器的性能提供了必要的依据以及理论指导。     

GaN蓝色激光二极管的研究进展

ＧａＮ短波长激光器是最近取得突破性进展而备受关注的光是这研究新域。本文简要论述了２０多年来在发展ＧａＮ发光器件过程中所克服的困难,介绍了目前这类激光器在解理法制备谐振腔端面、干法腐蚀和欧姆接触等关键工艺的进展情况。最后,综述了在获得室温下脉冲及连续工作的ＧａＮ蓝色激光二官的研究方面所取得的最新进展。     

GaN基蓝紫光激光器的材料生长和器件研制

报道了国内首次研制成功的GaN基蓝紫光激光器的材料外延生长、器件工艺和特性.用MOCVD生长了高质量的GaN及其量子阱异质结材料,以及异质结分别限制量子阱激光器结构材料.GaN材料的X射线双晶衍射摇摆曲线(0002)对称衍射和(10(-1)2)斜对称衍射半宽分别为180″和185″;3μm厚GaN薄膜室温电子迁移率达到850cm2/(V·s).基于以上材料,分别成功研制了室温脉冲激射增益波导和脊型波导激光器,阈值电流密度分别为50和5kA/cm2,激光发射波长为405.9nm,脊型波导结构激光器输出光功率大于100mW.     

脊形结构GaN蓝光激光器的热模拟分析

利用二维热传导模型分析了GaN激光器的温度特性.计算了有源区在连续工作条件下的最大温升,分析了激光器工作时的功率密度和p电极比接触电阻率等参数对温度特性的影响.模拟结果表明,采用不同衬底和不同装配形式对器件温度特性的影响很大,正装形式下,窄的脊形条宽能提高器件的高温工作稳定性.     

Visible fiber lasers excited by GaN laser diodes

This paper describes and discusses visible fiber lasers that are excited by GaN laser diodes. One of the attractive points of visible light is that the human eye is sensitive to it between 400 and 700 nm, and therefore we can see applications in display technology. Of course, many other applications exist. First, we briefly review previously developed visible lasers in the gas, liquid, and solid-state phases and describe the history of primary solid-state visible laser research by focusing on rare-earth doped fluoride media, including glasses and crystals, to clarify the differences and the merits of primary solid-state visible lasers. We also demonstrate over 1 W operation of a Pr:WPFG fiber laser due to high-power GaN laser diodes and low-loss optical fibers (0.1 dB/m) made by waterproof fluoride glasses. This new optical fiber glass is based on an AlF₃ system fluoride glass, and its waterproof property is much better than the well known fluoride glass of ZBLAN.     

GaN 基材料生长及其在光电器件领域的应用

GaN具有禁带宽，热导率高，电子饱和漂移速度大和介电常数小等特点，在高度亮发光二极管，短波长激光二极管，高性能紫外探测器和高温，高频，大功率半导体器件等领域有着广泛的应用前景。本文介绍了GaN基半导体材料的制备方法，异质结构以及在光电子和微电子器件领域的应用，并讨论了今后的发展趋势。     

Visible InGaN/GaN Quantum-Dot Materials and Devices

General properties of III-V nitride-based quantum dots (QDs) are presented, with a special emphasis on InGaN/GaN QDs for visible optoelectronic devices. Stranski-Krastanov GaN/AlN dots are first discussed as a prototypical system. It is shown that the optical transition energies are governed by a giant quantum-confined Stark effect, which is the consequence of the presence of a large built-in internal electric field of several MV/cm. Then we move to InGaN/GaN QDs, reviewing the different fabrication approaches and their main optical properties. In particular, we focus on InGaN dots that are formed spontaneously by In composition fluctuations in InGaN quantum wells. Finally, some advantages and limitations of nitride laser diodes with active regions based on InGaN QDs are discussed, pointing out the requirements on dot uniformity and density in order to be able to exploit the expected quantum confinement effects in future devices.     

Characteristics of a GaN-based Gunn diode for THz signal generation

A generalized large-signal computer simulation program for a Gunn oscillator has been developed.The properties of a Gunn diode oscillator based on the widely explored GaN,are investigated using the dev...     

LED光电器件的性能调控

制备了具有高量子效率的发光二极管(LED)器件。对于LED光电器件提高辐射复合速率有利于缓解电子泄露,增加了LED的发光功率,缓解了LED在大电流下的效率下降问题。本文通过采用InGaN/GaN作为LED的垒层,减小由极化引起的静电场,增大电子和空穴波函数的交叠比,从而增大了辐射复合速率。     

The effect of substrate surface roughness on GaN growth using MOCVD process

Efficiency and lifetime of light emitting diodes and laser diodes inversely depend on defect density of the crystal, and reduction of defect density is accomplished by a proper choice of substrate or a deliberate modification of the substrate surface. Buffer growth or nitridation can yield an atomically flat surface and the roughness of a substrate surface for GaN deposition can be controlled by either method such that lateral film growth can be promoted. The effect of nanoscale surface roughness on photoluminescence and crystal quality of GaN/Al₂O₃ (0001) has been studied. The optimal conditions for N₂-nitridation or/and GaN-buffer growth correlate well with the minimum surface roughness and surface morphology as determined by atomic force microscopy and it is suggested that this can be used for process optimization of GaN film growth.