双极集成电路的闭锁通道

采用各种实验技术的综合方法,发现了双极集成电路中的闭锁通道。用电压衬度扫描电子显微技术作为分析闭锁通道的内部探测。从6种器件上获得的数据表明,各种不同的通道组合和相互作用是造成闭锁的原因。     

电力电子系统应用的时间域网络解析器的精确度和速度

本文通过比较5个商业软件包的精确度和执行时间，研究了具有固定时间和变换时间的网络仿真方法的性能差异。包含了多个三相二极管整流器和一个PWM电压源逆变器的一系列基准实例显示：对于线性电路来说，固定时间步长法的仿真时间更短一些；然而，为了得到精确的结果，即使对于低开关频率的PWM应用都可能需要非常小的时间步长。否则，如果使用的时间步长过大，即使波形看起来是正确的，PWM逆变器控制信号也可能有严重的错误。     

THE PROBLEM OF LIMIT CYCLES FOR A LIENARD TYPE CUBIC SYSTEM

The purpose of this paper is to study a general Lienard type cubic system with one antisaddle and two saddles. We give some results of the existence and uniqueness of limit cycles as well as the evolution of limit cycles around the antisaddle for system (2) in the following when parameter a1 changes.     

Effect of Notoginsenoside-Rg_1 on the Expression of Several Proteins in the Striatum of Rat Models with Parkinson′s Disease

Introduction Parkinson′sdisease(PD),alsocalledshaking palsy,isaneurodegenerativedisorderandfrequently occursinthepeopleabovetheageof65[1].PDisa relativelycommonneurodegenerativedisorder,which hasclinicalsymptomsincludingbradykinesia,rest tremor,rigidity,…     

Frozen Landweber Iteration for Nonlinear Ill-Posed Problems

In this paper we propose a modification of the Landweber iteration termed frozen Landweberiteration for nonlinear ill-posed problems.A convergence analysis for this iteration is presented.The numericalperformance of this frozen Landweber iteration for a nonlinear Hammerstein integral equation is compared withthat of the Landweber iteration.We obtain a shorter running time of the frozen Landweber iteration based onthe same convergence accuracy.     

Markarian 8星系的包层辐射

使用美国甚大天线阵(VLA).对Markarian 8星系进行了多频观测.多频VLA观测表明,Markarian 8星系有三个主要的射电子成份,它们浸在一个弥漫的星系包层中.包层的射电谱是陡的非热谱.本文根据VLA观测确定了包层的物理参量,并讨论了包层中相对论性电子的可能起因.本文估计了包层非热辐射所要求的超新星爆发率.     

一种新的亚微米制造技术

已经研制成功一种制作亚微米线宽和器件的新技术。此技术不需要电子束或其它外加的刻蚀技术,而只用常规光刻法和一次边缘选择镀工序。在此工序中,把金属镀到已刻图案的金属层的边缘上。然后,此已镀边缘作为下步等离子腐蚀的掩模,以腐蚀其下层的导体或介质。此技术作出的线宽小至0.04微米,并能用来制造多种微波器件。特别是已用它来制作栅长为0.1微米的镀金铬栅 GaAsMESFET。此法所得 GaAsMESFET 的性能,比得上用比较复杂和花费大的制作栅图案技术制造出来的器件。譬如,在离子注入的 GaAs 上制作的5微米源-漏间距,0.3微米栅长和250微米栅宽的 MESFET,12千兆赫下最大可用增益超过10分贝。     

单块峯值检波器

我们将讨论用于克服频率补偿问题的单块峯值检波器。虽然器件已缩减到一个单块,但仍具有一个小系统的特性。象这样有利于一个系统设计方法,是为了控制电荷注入和输出放大器的场效应晶体管(FET)输入端实现消除高温漏电流的目的,电路设计利用在单块电路中获得的固有的匹配。 图(1)中的典型峯值检波器用了电压放大器和一个二极管或者一个射极跟随器,对电容C_H不定向地充电。A_1“+”端的输出阻抗加上二极管的动态阻抗r_d,组成在反馈回路中确定极点的电阻。二极管的动态阻抗r_d等于(KT/g)/Id,这里Id是对C_H的充电电流。所以极点向S平面的源极转移,其误差等于零。由于极点闭合在系统的反馈回路中,极点移动的本身将不会可观地延长所得时间。但是,在典型的电压放大器的频率补偿中,     

A NOVEL METHOD FOR FABRICATING COMPOSITE MOSAIC MEMBRANE WITH UNIQUE NF SELECTIVITY

A novel method of fabricating composite mosaic membranes was studied on the basis of interracial polymerization （IP） by coating a thin selective layer onto the surface of a micro-porous hollow-fiber membrane, in which, 2,5-diaminobenzene sulfonic acid was used as one monomer of the IP reaction, and a mixture of trimesoyl chloride （TMCI） and 4-（chloromethyl） benzoyl chloride as the other monomer. Through the IP reaction a thin selective layer with negatively charged groups could be first formed on the polyethersulfone （PES） support membrane. Then trimethylamine solution was introduced to modify the IP layer through a quaternization reaction. Thus the selective layer of this composite membrane contained both negatively charged and positively charged groups to perform the mosaic functionality. Characterization of the composite mosaic membranes was carried out through permeation experiments using different inorganic salts and dyes. The experimental results showed that the membranes could permeate both mono- and bi-valent inorganic salts, but reject larger organic molecules. Such a mosaic membrane is potentially useful for the separation of salts from water-soluble organics, especially in dye and textile industries.     

硅片步进机光学系统

菲利浦实验室设计用于直接在硅片上制作集成电路光掩模图形的分步重复投影曝光装置—Silicon Repeater,曾在早期发行的本刊中有过简结的叙述。经过对初始样机的不断改进,目前此技术已日趋成熟,能以更高的分辨率对硅片进行高速曝光。本文阐述了Silicon Repeater 最佳的技术规格——主要由物理极限来确定的可见光光学系統的先进设计。