温度对双光子光折变介质中光伏孤子特性的影响

具有双光子光折变效应的光折变介质温度的变化对光伏孤子性质具有影响。通过光伏空间孤子的演化方程得到的亮和暗光伏空间孤子解与温度相关,在室温范围内,双光子光折变介质中空间孤子的光强和强度半峰全宽(FWHM)均受温度影响。随着介质温度的升高,双光子光折变介质支持光强较小的光伏空间孤子;在较大光强情况下,双光子光折变介质支持强度半峰全宽较小的光伏空间孤子;在小光强情况下,双光子光折变介质支持强度半峰全宽较大的光伏空间孤子。即可以通过控制光折变介质的温度来控制介质中光伏孤子的空间形态,从而在光折变介质中形成稳定的光伏空间孤子。     

室温CdZnTe核辐射探测器研究进展

简述了CdZnTe材料与探测器的发展、国内外的研究现状及其广泛应用,分析了存在的问题和解决方法,同时介绍了本单位CdZnTe探测器的研发情况,包括探测器的制备工艺及性能测试与分析.制备出了性能优良的阵列像素(3×3)探测器,其57Co 122 keV光谱能量分辨率为23.7%(28.9 keV FWHM),137Cs 662 kev光谱分辨率为17.9%(117.8 keV FWHM).     

φ200mm太阳能电池用直拉硅单晶生长中导流系统的研究

利用数值模拟,对CZ硅单晶生长系统中导流系统调整和改进.得到不同导流系统下的氩气流场和伞局温场.研究发现在导流系统中引入导流筒及冷却功能后,氩气流场得到明显的改善,晶体中纵向温度梯度均匀性改善,同液界面趋于平坦,有利于结晶潜热的散发和单晶径向电阻率的均匀性.研究表明改进导流系统能提高结品潜热散发速率,有利于提高晶体拉速.     

不同气氛保护下退火制备的CuO/SiO2复合薄膜微观结构分析

采用射频磁控共溅射法在Si(111)衬底上沉积Cu/SiO2复合薄膜.然后在N2和NH3保护下高温退火,再于空气中自然冷却氧化,制备出CuO结构,并对其微观结构进行分析.N2保护下退火温度为1100℃时样品中主晶相为立方晶系的CuO(200)晶面,薄膜样品表面出现纳米线状结构,表面组分主要包括Cu,O元素,冷却氧化形成CuO/SiO2复合薄膜.NH3气氛保护下退火,随着退火温度的升高,CuO由单斜晶相逐渐转变为立方晶相,CuO薄膜结晶质量提高.样品于900℃和1100℃退火后,形成有序散落的微米级颗粒,前者由粒状团簇组成,颗粒表面比较粗糙;后者由片融状小颗粒融合而成,颗粒表面比较光滑.     

On Guaranteed Smooth Switching for Buffered Crossbar Switches

Scalability considerations drive the evolution of switch design from output queueing to input queueing and further to combined input and crosspoint queueing (CICQ). However, CICQ switches with credit-based flow control face new challenges of scalability and predictability. In this paper, we propose a novel approach of rate-based smoothed switching, and design a CICQ switch called the smoothed buffered crossbar or sBUX. First, the concept of smoothness is developed from two complementary perspectives of covering and spacing, which, commonly known as fairness and jitter, are unified in the same model. Second, a smoothed multiplexer sMUX is designed that allocates bandwidth among competing flows sharing a link and guarantees almost ideal smoothness for each flow. Third, the buffered crossbar sBUX is designed that uses the scheduler sMUX at each input and output, and a two-cell buffer at each crosspoint. It is proved that sBUX guarantees 100% throughput for real-time services and almost ideal smoothness for each flow. Fourth, an on-line bandwidth regulator is designed that periodically estimates bandwidth demand and generates admissible allocations, which enables sBUX to support best-effort services. Simulation shows almost 100% throughput and multi-microsecond average delay. In particular, neither credit-based flow control or speed-up is used, and arbitrary fabric-internal latency is allowed between line cards and the switch core, simplifying the switch implementation.     

IPv4地址不足解决方案综述

IPv4地址不足的问题日益严重,业界主要有两条解决路径:一是非兼容方式的升位,这就是采用全新的IP地址协议,如IPv6;另外一条路径是采用兼容方式的路径,如NAT(网络地址转换)技术、SuIP(超级协议)技术.文章对IPv6,NAT以及SuIP等三种技术的优势和不足进行了分析,然后对这三种技术进行了比较,最后展望了这三种解决方案的发展前景.     

绿色电子信息产品的概念与技术要求

随着越来越多的环境问题出现,绿色产品已经成为当前社会关注的焦点。电子信息产品在我国制造业中具有举足轻重的作用,大力开展绿色电子信息产品的设计与制造利国利民。文章介绍了绿色产品的基本概念,提出了绿色电子信息产品的基本技术要求,最后以手机为例进行了进一步阐述。     

Effect of Pulse-Plated Nickel Barriers on Tin Whisker Growth for Pure Tin Solder Joints

We investigate the influence of pulse-plated Ni barriers, compared to direct current (DC)-plated Ni barriers, on the growth of Sn whiskers in laminated Cu/Ni/Sn samples. The results indicate that the pulse-plated Ni barriers exhibit much better resistance to Sn whisker growth than the DC-plated Ni barriers, i.e., when exposed to ambient of 60°C and 93% relative humidity (RH) for 40 days only a few small hillocks were observed as opposed to the long whiskers and large nodules of Sn for the DC-plated Ni barriers. The underlying mechanisms are addressed based on the texture characteristics of the plated Ni and Sn layers and the formation of intermetallic compounds.     

基于Log-WT的人脸图像超分辨率重建

目前已有的基于学习的人脸超分辨率图像重建算法大都对亮度变化特别是阴影非常敏感,针对这一缺点,该文提出了一种不随光照变化的图像表示方法对数-小波变换(Log-WT),并在此基础上构造了一种新的人脸超分辨率图像重建算法。该方法首先利用Log-WT变换提取低分辨率图像与光照无关的内在特性,然后借助流形学习的思想建模高分辨率图像和低分辨率图像之间的关系,并对其加入人脸图像的专用先验约束,从而同时实现了超分辨率重建和图像增强。仿真结果表明该算法有效克服了传统方法受光照因素影响的缺点,在提高图像分辨率的同时克服了光照因素的影响,特别是对阴影效应的消除具有明显效果,将该方法应用于人脸识别,有效提高了识别率。     

基于创新扩散的多预约802.11e协议及性能分析

该文为Ad hoc网络媒质接入层提出了一种基于802.11e协议的支持区分服务支持的协议。该协议采取多预约机制提高高优先级数据业务在信道竞争中的优势,并且采用创新的扩散原理协调降低各个低优先级数据业务的接入概率,保护高优先级数据流,同时避免了这种协调信息在全网络范围内的洪泛。理论分析与仿真结果均表明,该扩展协议提高了高优先级数据流的接入概率和端到端吞吐量,显著的降低高等级业务的端到端时延及抖动。