摄像型等厚干涉实验仪器的研究

介绍了“摄像型等厚干涉实验仪”的构造及等厚干涉实验新的测量方法。     

On the environmental decoherence and spin interference in mesoscopic loop structures

Mechanisms of ‘environmental decoherence’ such as surface scattering, Elliot–Yafet process and precession mechanisms, as well as their influence on the spin phase relaxation are considered and compared. It is shown that the ‘spin ballistic’ regime is possible, when the phase relaxation length for the spin part of the wave function (L^(s)) is much greater than the phase relaxation length for the ‘orbital part’ (L^(e)). In the presence of an additional magnetic field, the spin part of the electron's wave function (WF) acquires a phase shift due to additional spin precession about that field. If the structure length L is chosen to be L^(s)>L>L^(e), it is possible to ‘wash out’ the quantum interference related to the phase coherence of the ‘orbital part’ of the WF, retaining at the same time that related to the phase coherence of the spin part and, hence, to reveal corresponding conductance oscillations.     

PERFORMANCE OF THREE STAGE TURBO－EQUALIZATION－DECODING

An increasing demand for high data rate transmission and protection over bandlimited channels with severe inter-symbol interference has resulted in a flurry of activity to improve channel equalization. In conjunction with equalization, channel coding-decoding can be employed to improve system performance. In this letter, the performance of the three stageturbo-equalization-decoding employing log maximum a posteriori probability is experimentally evaluated by a fading simulator. The BER is evaluated using various information sequence and interleaver sizes taking into account that the communication medium is a noisy inter symbol interference channel.     

量子阱红外探测器能带结构的计算

利用电子波在阱与垒的界面上的反射及干涉效应，计算了量子阱红外探测器(QWIP)的能带结构，并对其适用性进行了分析和讨论。通过与K-P模型比较发现，本方法对计算较宽势阱(阱宽大于4nm)的量子阱结构的电子态适合。在垒宽和阱宽不变条件下，用两种方法计算得到的AlGaAs／GaAs量子阱材料中Al组分x与吸收峰值波长λp的关系曲线基本相同。结果说明，在较宽的范围内，本方法对QWIP能带结构的计算是适用且简便的。     

多模干涉型集成光学器件研究进展

基于自镜像效应(SIE)的多模干涉(MMI)型集成光学器件是集成光学中具有广泛用途的重要器件。本文详细而系统地综述了近几年来MMI器在国内外的研究进展，特别是其在集成光学中的应用。     

基于CCD的激光微位移测量系统研究

介绍了一种基于多普勒效应的可进行动态微位移测量的激光微位移测量系统。该系统以He-Ne激光器为光源,配以干涉系统移动方向判别及分频系统、CCD视频信号的高速动态采集系统、微机处理系统及干涉图处理软件包等。与传统测量方法相比,其精度、灵敏度及稳定性都有较大提高,并实现了微位移的全自动测量。     

线性电压扫描下1VIIS器件瞬态的简单模型

本文用准平衡模型分析讨论了线性电压扫描下MIS器件的I/V瞬态.文中除了给出一般的处理方法以外，还给出了几种不同电压扫描率下I/Y特性的计算结果，并与已往的模型作了比较.     

关于电磁屏蔽

本文从场的角度阐述了电磁屏蔽原理,计算方法及实际中考虑屏蔽应注意的问题。提出了组合屏蔽方式。     

The performance of a direct-sequence spread-spectrum acquisition system using a linear prediction filter for narrowband interference suppression

The coarse acquisition performance of a direct sequence spread-spectrum receiver is analyzed when a linear prediction filter is used for narrowband interference suppression. We show that once an appropriate matching strategy is identified, the linear prediction filter can provide favorable performance when narrowband interference is present over a considerable range of both interference power and bandwidth. In addition, the presence of the filter dramatically improves the performance over the case where there is no filter, except when the interference bandwidth and the power are both small (i.e., when the processing gain provides sufficient interference immunity without the filter). If long spreading sequences are used with moderately sized observation windows, the acquisition performance can be severely degraded when a parallel acquisition scheme is used due to the linear predication filter. We show, however, that a slower serial receiver will provide reliable performance.This work was supported in part by the Office of Naval Research under contract ONR N00014-91-J-1234, the Army Research Office under contract ARO DAAL03-91-0071, and the NSF Center for Ultra-High Speed Circuits and Systems (ICAS).