相干光纤通信系统中的偏振分集接收机的实验研究

本文讨论了相干光纤通信系统中的偏振分集接收机的基本原理,并在实验中首次实现了基于偏振分集的偏振不敏感接收。在调制信号为137.2MHz和146.0MHz正弦波的情况下,得到了很好的与信号偏振面无关的解调信号。这一结果正在应用于1.5μm波段140Mb/s FSK相干光纤通信系统之中。     

IMPLEMENTING THE ADAPTIVE VECTOR QUANTIZER USING CARPENTER/GROSSBERG NET

AVQ(Adaptive Vector Quantizer)overcomes some shortcomings of traditional vectorquantizer with a fixed codebook trained and generated by the LBG or other algorithms by applyinga variab|e codebook.In this paper,we describe an effective and efficient implementation of AVQby modifying the CCN(Carpenter/Grossberg Net).The encoding process of AVQ is very similarto the learning process of the CGN.We study several different encoding schemes,includingwaveform AVQ,analysed parameter AVQ and so on,implemented by the CGN.And we simulatethe encoding performance of each scheme for encoding Gaussian process source,first order Gauss-Markov process source and practical speech signal.Our simulation results show that good qualityboth in subjective and objective tests can be obtained in a low or middle bit rate range.     

多晶硅膜离子注入和扩散掺杂制备浅结的研究

本文对多晶硅膜离子注入掺杂和扩散掺杂制备浅发射结进行了实验研究。针对新型薄发射极晶闸管特性改善对薄发射极参数的要求,重点研究了采用不同方法时退火条件对薄发射区掺杂剖面、结深以及杂质总量的影响。管芯研究结果表明,在适当的退火条件下,离子注入掺杂制备浅结是改善器件特性较为理想的方法。     

A two-dimensional nonisothermal finite element simulation of laserdiodes

A fully self-consistent nonisothermal, two-dimensional model of a semiconductor laser device is presented. The model consists of the simultaneous solution of the electrical equations (Poisson's and electron and hole continuity equations), along with the wave equation, photon rate equation, and thermal conduction equation. An analysis is presented for an AlGaAs-GaAs ridge laser diode structure using this model as a representative example. The results agree well with available experimental data. A comparison of the results between isothermal and nonisothermal simulations shows that the nonisothermal case has a higher threshold current and lower quantum efficiency than the idealized isothermal model. The result was found to depend critically on the thermal exchange boundary condition of the simulated device, demonstrating the importance of considering thermal exchange in the design of laser diodes     

X射线能谱分析中对铁的百分含量修正的理论推导和实验测定

在KYKY-1000B扫描电镜上进行X射线能谱分析时,常出现附加的铁峰。本文从理论上对产生附加铁峰的原因作出了解释,并推导出附加铁峰强度和样品原子序数的函数关系的解析表达式,同时对附加的铁的百分含量进行了实验测量。由实验数据拟合得出的实验曲线和理论分析得出的表达很好地符合。     

低气压放电灯阴极发射特性的测试与研究

用射频噪声法测出了低气压放电灯(荧光灯、紧凑型节能灯、紫外杀菌灯等)阴极的零场发射电流,进而研究了阴极温度和阴极零场发射之间的变化规律,最后,得到了一种比较简单、方便、实用的测试阴极发射特性的方法。     

长波长1.3μm光纤放大器的探索

本文对光纤通信长波长1.3μm运用的掺镨氟化物光纤放大器在国外探索实验的现状作了简单介绍。首先简介光纤放大器作用的原理,着重说明1.3μm光纤放大器如何选择纤芯的掺离子和玻璃成份。然后介绍小信号放大器和功率放大器及抽引光源在实验室测量的典型性能数据。文束估计不久的将来,这种1.3μm光纤放大器有把握制成产品,供数字通信网和模拟有线电视网使用。     

Field-dependence of the area-density of 'cold' electron emission sites on broad-area CVD diamond films

A high area density of field-induced electron emission sites has been observed on broad-area (12 mm in diameter) CVD diamond films deposited on molybdenum substrates. Furthermore, it was found that the density increased with the electric field applied to the surface of the films. These findings indicate that the CVD diamond film has to be seen as a potentially favoured candidate among electronic materials for the development of new types of cold cathode electron source.<>     

用于求解TSP的HOPFIELD／TANK网络模型的特性及参数的理论分析＊

本文对于Hopfield/Tank网络模型在求解TSP的特性进行了理论分析。建立了参数之间的关系准则。     

瞬态电荷收集法研究a—Si：H／a—SiN：H界面处的电子积累＊

本文介绍一种研究a-Si:H/a-SiN:H界面层电子积累特性的新方法,所用样品为Cr/a-SiN:H/a-Si:H/(n+)a-Si:H/AI.测试表明,a-Si:H/a-SiN:H界面是一个电子积累层,其电子面密度为3.2×10~(11)/cm~2,并且界面层中的电子面密度随外加电压的增加而线性增加。实验结果与理论分析相一致。