三异丙氧基铝的制备及催化机理

本文介绍了采用新的原料予处理方法合成三异丙氧基铝，并且选择更为合理的工艺手段精制产品，同时探讨了产物的催化合成机理。     

激光器绝热啁啾对光纤通信系统传输特性的影响

通过理论分析、实验和计算机模拟得到：进行直接强度调制时，体块型DFB激光器的总微分量子效率（与多量子阱DFB激光器相比）过低，从而导致其绝热啁啾占激光器啁啾的主要部分；用于无再生中继距离较大的强度调制／直接检测（IM／DD）光纤通信系统时，色散效应将导致信号脉冲上升沿压缩，使系统误码率增加。据此建议：在无再生中继距离大于100～120km的常规单模光纤IM／DD系统中，应采用多量子阱激光器。     

可调90°偏振面旋转器

给出一种可调式90°偏振面旋转器。调整复合片快轴的夹角α,便能在可见光范围内使用.     

Structure and damping properties of polydimethylsiloxane and polymethacrylate sequential interpenetrating polymer networks

By using the technology of the sequential interpenetrating polymer network, a series of novel damping materials based on a polydimethylsiloxane (PDMS)/polyacrylate (PAC) matrix with polymethacrylate (PMAC) were synthesized. They have a controllable broad transition peak spanning the temperature range of 150–220°C and the medial value of loss factor with maximum of 0.35–0.60. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) were applied to analyze and characterize the transition behavior and the microphase structure of the materials. It was found that the size and height of a transition peak at both the low‐ and the high‐temperature zones change as a function not only of the concentration of PMAC and PDMS but also of the kind of PMAC; simultaneously, the low‐ temperature behavior was also governed by the crystallization of PDMS. The content of the crosslinking agent exerts a significant influence on the configuration of the curves of the transition peaks. AFM shows a characteristic phase morphology of double‐phase continuity containing a transition layer and domain less than 1 μm, indicating that the interwoven multilayer networks are the key to incorporation of the immiscible components and form a broad damping functional region. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 545–551, 2002     

国外模拟IC的发展现状分析

本文主要根据电子整机的发展要求,从集成化、高性能和高可靠等三方面分析国外模似IC的发展,进而说明模拟IC总的发展趋势及其表现。最后指出,模拟IC正面临一个新的变革时期。     

Scattering parameters of a waveguide cross junction loaded with a metallic post in the center

In this paper, the scattering parameters of a waveguide cross junction loaded with a metallic post in the center are analyzed for the first time by using the Method of Lines. The homogeneous boundary condition of the third kind and curved boundary are introduced in the formulation. Numerical results are in good agreement with the experimental data. The scattering parameters at Ka-band and W-band of the cross junctions loaded with metallic posts of different radii are presented. It is shown from the numerical results that loaded with metallic posts is an effective means for adjusting the network parameters of the waveguide cross junction to satisfy some special requirements in the design of millimeter wave components.     

Hydride Vapor Phase Epitaxy of GaN Thick Films by the Consecutive Deposition Process Using GaCl3

GaN buffer and main layers were grown by the conventional hydride vapor phase epitaxy technique using GaCl₃ consecutively. The deposited buffer layers were investigated by atomic force microscopy and X-ray analysis. To examine the behavior of the buffer layers at main layer growth temperature, heat treatment was conducted at 900°C. Based on the results of the buffer layer study, GaN thick films were grown at 1050°C. Optimum deposition conditions of buffer layer from the buffer and main layer studies generally coincided. On the φ scanning pattern, the GaN films grown on (0001) Al₂O₃ were single-crystalline. Band-edge emission dominated photoluminescence was observed at room temperature.     

ZXJ10机IN业务功能扩展及实现

本文从智能网的基本概念入手,论述了利用 ZXJ10程控交换系统为发展智能网业务提供支持功能的技术策略以及分阶段实现的过程,并对各个阶段能够实现的业务作了简要介绍。     

线性复合片补偿器

本文给出一种特殊复合延迟片——复合片补偿器。改变入射线偏振光的振动方位角,便可改变补偿器的延迟量,调整简单,精度高。     

采用激光光刀的叶片三维面形测量方法

提出一种采用激光光刀的叶片三维面形测量方法。介绍了方法原理、系统结构、信息获取与处理方案,并给出了对实际飞机发动机叶片的面形测量结果。