GaAs MESFET栅取向效应中背栅的作用

根据压电效应模型,本文详细研究了压电电荷对GaAs MESFET沟道与衬底界面耗尽层的影响。认为正压电电荷比负压电电荷所引起的阀值电压漂移大,较好解释了(100)衬底上沿[011]和[011]取向的GaAs MESFET阈值电压非对称反向漂移的现象。     

光纤电视系统

随着我国经济的发展,光纤(有线)电视系统也将在全国有一个大发展。本文将目前光纤电视技术的发展情况用深入浅出的文字作一综合叙述,其中包括光纤电视和目前无线电广播电视在质量上的比较、光纤电视系统及其布线结构。对光纤电视系统的两项重要技术:调制及多路复用,作了进一步探讨,提出了有关光纤电视系统将来在技术方面的可能发展。最后作者对我国发展光纤电视系统提出了一些看法。     

CCD摄像机在瞬变喷雾可视化中的应用

结合作者近年来在早稻田大学和上海交通大学的研究工作,介绍了高速CCD摄像机在柴油机喷雾测试中的应用。重点论述了利用红宝石激光器和CCD(电荷耦合器件)视频摄像机的特点实时采集瞬变燃油喷雾图像的技术,并讨论了其中的关键问题。     

基于MFFAKF的微惯导磁匹配粗对准方法

针对微机电系统(MEMS)陀螺仪精度低,无法完成惯导系统方位对准的问题,该文提出一种采用加速度计与磁强计输出完成MEMS惯导系统粗对准法。同时针对遗忘卡尔曼滤波法的缺点,提出将一种多遗忘因子自适应卡尔曼滤波法(MFFAKF)引入系统的对准方案中。该方法通过基于指数渐消记忆的方式计算量测噪声方差阵,并采用多遗忘因子调节不同的滤波通道。实验结果表明,采用MFFAKF得到的粗对准航向角精度满足MEMS惯导系统粗对准要求。     

Highly Oriented Nanofibrils of Regioregular Poly(3‐hexylthiophene) Formed via Block Copolymer Self‐Assembly in Liquid Crystals

A novel method making use of block copolymer self‐assembly in nematic liquid crystals (LCs) is described for preparing macroscopically oriented nanofibrils of π‐conjugated semiconducting polymers. Upon cooling, a diblock copolymer composed of regioregular poly(3‐hexylthiophene) (P3HT) and a liquid crystalline polymer (LCP) in a block‐selective LC solvent can self‐assemble into oriented nanofibrils exhibiting highly anisotropic absorption and polarized photoluminescence emission. An unusual feature of the nanofibrils is that P3HT chains are oriented along the fibrils' long axis. This general method makes it possible to use LCs as an anisotropic medium to grow oriented nanofibrils of many semiconducting polymers insoluble in LCs.     

A study of lubricants on silver flakes for microelectronicsconductive adhesives

Conductive adhesives are composites of polymer matrixes and metal fillers (conductive elements). Silver (Ag) flakes are widely used as fillers for electrically conductive adhesives (ECAs). Generally, there is a thin layer of organic lubricant coated on the commercial Ag flake surface. This lubricant layer is needed for eliminating the Ag particle agglomeration while dispersing the Ag filler into the polymeric resin. Therefore the lubricant influences rheology, conductivity, and other properties of ECA's. The nature of the lubricant on a Ag flake and the interaction between the lubricant and the Ag flake surface were studied by diffuse reflectance infrared spectroscopy (DRIR). Thermal decomposition of the lubricant was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In addition, the effects of some chemical compounds on lubricant removal and the enhancement of conductivity of the ECA were also investigated. It was found that 1) a chemical bonding was formed on the Ag flake surface between the lubricant and Ag; 2) the short chain acids replaced the long chain lubricants; 3) an ether and a poly(ethylene glycol) enhanced electrical conductivity by partially removing the Ag flake lubricants     

电信级企业融合通信系统架构研究

企业通信需求正在从以语音为主向多媒体融合通信方式发展。本文从企业通信的现状出发,分析了建立电信级企业融合通信系统的必要性,对其基于NGN的系统模型、组网方案等方面进行了探讨。     

An Injection-Locked Frequency Divider With Multiple Highly Nonlinear Injection Stages and Large Division Ratios

An injection-locked frequency divider (ILFD) with multiple highly nonlinear injection stages is discussed. Implemented in a standard 0.18-mum CMOS technology, measurement shows that multiple division ratios from 6 to 18 are achieved while the locking ranges are all above 1.7 GHz without the need for additional tuning. The ILFD can be locked at the maximum injection frequency of 11 GHz with the power consumption no more than 7.2 mW from a 1.8-V power supply     

Modulation of Electron Structure and Dehydrogenation Kinetics of Nickel Phosphide for Hydrazine-Assisted Self-Powered Hydrogen Production in Seawater

The electrocatalytic production of hydrogen from seawater provides a low-cost way to realize energy conversion, but is restricted by high potential for seawater electrolysis and the chlorine oxidation reaction (ClOR) at the anode. Here, the self-growth of Mo-doped Ni₂P nanosheet arrays with rich P vacancies on molybdenum-nickel foam (MNF) (Mo-Ni₂P_v@MNF) is reported as bifunctional catalyst for Cl-free hydrogen production by coupling hydrogen evolution reaction (HER) with hydrazine oxidation reaction (HzOR) in seawater. Impressively, the Mo-Ni₂P_v@MNF electrode as bifunctional catalyst has an excellent activity for overall hydrazine splitting (OHzS) with an ultralow voltage of only 571 mV at 1000 mA cm⁻² and can maintain stability for an ultra-long time of 1000 h at 100 mA cm⁻². Moreover, integration of OHzS into self-assembled hydrazine fuel cells (DHzFC) or solar cells can enable the self-powered H₂ production. The industrial hydrazine sewage as feed for the above eletrolysis system can be degraded to ≈5 ppb rapidly. Density functional thoery calculations demonstrate that the electronic structure modulation induced by P vacancies and Mo doping can not only achieve thermoneutral ΔG_H* for hydrogen evolution reaction but also enhance dehydrogenation kinetics from *N₂H₄ to *NHNH₂ for HzOR, achieving enhanced dehydrogenation kinetics.