基于PLC控制技术的电梯控制系统的设计与实现

为了实现电梯的自动控制,使其运行灵活方便．稳定可靠、抗干扰能力强。本文基于PLC控制技术,介绍了PLC技术控制下的电梯系统组成和工作过程,并阐述了PLC技术控制下电梯系统实现的功能、设计思路、实现的语言和算法。     

基于虚拟无线电技术的数据采集系统的设计

介绍了一个基于虚拟无线电技术的高速数据采集系统的设计及其实现，对其结构和性能作了简要说明，同时介绍了模数转换器AD6644和数字下变频器GC4016的基本特性，最后给出了详细的实验结果。     

基于J2EE的综合营业系统的设计

文中主要介绍了综合营业系统的设计过程，系统设计采用了J2EE技术，运用MVC的设计思想，通过Struts实现系统架构，简化了软件的开发，提高了软件的灵活性、可扩展性和重用性。     

县级电视台制播系统数字化、网络化改造

针对县级电视台节目制作系统与播出系统存在的严重脱节问题，介绍如何利用网络技术和数字技术对制播系统进行数字化、网络化改造，从数字化、网络化改造的必要性及技术方案、设计原则等方面。阐述了县级电视台实现数字化、网络化的途径。     

网络技术在南京地铁，AFC系统中的应用

本文详细介绍了计算机网络技术在南京地铁一号线AFC系统中的应用。在对南京地铁AFC系统网络概述的基础上，结合CISCO网络技术分析了AFC系统的网络结构和功能实现，分析了AFC系统的网络管理和安全措施，最后总结了南京地铁AFC系统的网络设计特点。     

一个实用消息处理系统（MHS）的实现

本文主要介绍了一个实用ＭＨＳ系统的设计和实现技术，包括系统的结构、功能、汉化方案和ＲＵＡ的实现等。     

通信网网管系统性能评估技术研究

在网管系统的设计开发和更新完善过程中，网管系统评估技术是极为重要的辅助工具。首先介绍了网管评估技术的基本原理，然后从功能评估、效率评估和抗毁性评估三个方面探讨和研究了具体的评估指标。最后，在Visual C 编译环境下实现了一个网管评估系统的计算机仿真。     

群集系统的设计与实现

天津通信本地交换网管系统采用惠普公司的MC／ServiceGuard群集技术实现高可用性和高可靠性，保障全网话务和告警数据的准确性。在介绍群集的概念、特点以及MC／ServiceGuard技术原理的基础上，重点介绍网管系统的MC／ServiceGuard在天津通信网管系统的设计思路以及实现过程。     

七号信令链路级的设计和实现

介绍了七号信令系统链路级功能的设计和实现技术，并从原理到实现，从硬件到软件几个方面对系统设计进行了讨论。设计的模块已成功地用于ＫＹ－１０００交换机，并在电话网中稳定运行。所述方法也可用于交换机其它子系统和一般实时系统的设计。     

基于DSP的开发/高速处理系统的设计

在简要介绍TMS320C32芯片特点的基础上，讨论了由PC机与该芯片构成的主从系统框架。在力求实现实时性和用户专用性设计的原则下，设计完成了以TMS320C32为数字信号处理运算核心，以微机为控制系统，由DSP目标板和微机构成的一个高速数字信号处理系统。详细介绍了DSP开发／高速处理系统的基本原理，描述了系统的工作过程，介绍了利用该开发高速处理板形成两种用户系统的方法。     

Nonlinear analysis of GaN MESFETs with Volterra series using large-signal models including trapping effects

Nonlinearities in GaN MESFETs are reported using a large-signal physics-based model. The model accounts for the observed current collapse to determine the frequency dispersion of output resistance and transconductance. Calculated f/sub T/ and f/sub max/ of a 0.8 /spl mu/m/spl times/150 /spl mu/m GaN MESFET are 6.5 and 13 GHz, respectively, which are in close agreement with their measured values of 6 and 14 GHz, respectively. A Volterra-series technique is used to calculate size and frequency-dependent nonlinearities. For a 1.5 /spl mu/m/spl times/150 /spl mu/m FET operating at 1 GHz, the 1 dB compression point and output-referred third-order intercept point are 16.3 and 22.2 dBm, respectively. At the same frequency, the corresponding quantities are 19.6 and 30.5 dBm for a. 0.6 /spl mu/m/spl times/150 /spl mu/m FET. Similar improvements in third-order intermodulation for shorter gatelength devices are observed.     

Modal transforms in rectangular waveguide

Transformation matrices that allow conversion between normalised s-parameters in TE_z/TM_z, TE_x/TM_x and TE_y/TM_y format are presented. The transforms are simple to implement and are essential when comparing results expressed in terms of different modal solutions     

7B4--Absorption and emission properties of optically pumped ruby

Several experiments on optically excited ruby are described. First, absorption transitions initiated from the metastable states,tmin{2}max{3}²Eandtmin{2}max{3}²T1, are investigated in the photon energy range from 5500 to 45 000 cm^-1. The absorption spectrum of these excited states is determined in bothpi-and σ-polarizations and assignments for the observed absorption bands are achieved. Obtained results are compared with other experiments reported in the literature. Next, emission properties of pink ruby are studied in the region near theRlines. The emission spectrum is determined point by point by means of intense flash excitation. The observed weak bands are ascribed to theR'and phonon assistedRtransitions. Laser actions in these bands are discussed and experimental results on phonon terminated laser amplification are presented. An experiment using a giant pulse as an excitation source reveals that the transition time fromtmin{2}max{3}²Etotmin{2}max{3}²T1is shorter than a fraction of 1μs at room temperature.     

Design and performance of tunnel collector HBTs for microwave power amplifiers

AlGaAs/GaAs/GaAs and GaInP/GaAs/GaAs n-p-n heterojunction bipolar transistors (HBTs) are now in widespread use in microwave power amplifiers. In this paper, improved HBT structures are presented to address issues currently problematic for these devices: high offset and knee voltages and saturation charge storage. Reduced HBT offset and knee voltages (V/sub CE,os/ and V/sub k/) are important to improve the power amplifier efficiency. Reduced saturation charge storage is desirable to increase gain under conditions when the transistor saturates (such as in over-driven Class AB amplifiers and switching mode amplifiers). It is shown in this paper that HBT structures using a 100-/spl Aring/-thick layer of GaInP between the GaAs base, and collector layers are effective in reducing V/sub CE,os/ to 30 mV and V/sub k/ measured at a collector current density of 2/spl times/10/sup 4/ A/cm/sup 2/ to 0.3 V (while for conventional HBTs V/sub CE,os/=0.2 V and V/sub k/=0.5 V are typical). A five-fold reduction in saturation charge storage is simultaneously obtained.     

Carrier-induced change in refractive index of InP, GaAs and InGaAsP

The change in refractive index Δn produced by injection of free carriers in InP, GaAs, and InGaAsP is theoretically estimated. Bandfilling (Burstein-Moss effect), bandgap shrinkage, and free-carrier absorption (plasma effect) are included. Carrier concentrations of 10¹⁶/cm³ to 10¹⁹/cm ³ and photon energies of 0.8 to 2.0 eV are considered. Predictions for Δn are in reasonably good agreement with the limited experimental data available. Refractive index changes as large as 10^-2 are predicted for carrier concentrations of 10 ⁸/cm³ suggested that low-loss optical phase modulators and switches using carrier injection are feasible in these materials     

Order statistics from a logistic distribution and applications to survival and reliability analysis

Joint moments involving arbitrary powers of order statistics are the main concern. Consider order statistics u/sub 1/ /spl les/ u/sub 2/ /spl les/ /spl middot//spl middot//spl middot/ /spl les/ u/sub k/ coming from a simple random sample of size n from a real continuous population where u/sub 1/ = x/sub r(1):n/ is order-statistic #r/sub 1/, u/sub 2/ = x/sub r(1)+r(2):n/ is order statistic #(r/sub 1/ + r/sub 2/), et al., and u/sub k/ = x/sub r(1)+/spl middot//spl middot//spl middot/+r(k):n/ is order statistic #(r/sub 1/ +/spl middot//spl middot//spl middot/+ r/sub k/). Product moments are examined of the type E[u/sub 1//sup /spl alpha/(1)/ /spl middot/ u/sub 2//sup /spl alpha/(2)//sub /spl middot/ /spl middot//spl middot//spl middot//spl middot//u/sub k//sup /spl alpha/(k)/] where /spl alpha//sub 1/, ..., /spl alpha//sub k/ are arbitrary quantities that might be complex numbers, and E[/spl middot/] denotes the s-expected value. Some explicit evaluations are considered for a logistic population. Detailed evaluations of all integer moments of u/sub 1/ and recurrence relations, recurring only on the order of the moments, are given. Connections to survival functions in survival analysis, hazard functions in reliability situations, real type-1, type-2 /spl beta/ and Dirichlet distributions are also examined. Arbitrary product moments for the survival functions are evaluated. Very general results are obtained which can be used in many problems in various areas.     

Analysis of Optically Controlled Microwave/Millimeter-Wave Device Structures

Light-induced voltage and the change in the source-to-drain channel current under optical illumination higher than the semiconductor band gap for GaAs MESFET, InP MESFET, Al/sub 0.3/Ga/sub 0.7/As/GaAs high electron mobility transistor (HEMT), and GaAs permeable base transistor (PBT) are analytically obtained. The GaAs PBT and GaAs MESFET have higher sensitivity than the InP MESFET. However, the Al/sub 0.3/Ga/sub 0.7/As/ GaAs HEMT is observed to have the highest sensitivity. Variations in the small-signal parameters, such as channel conductance, gate-to-source capacitance, and transconductance, as well as transient parameters, such as switching time and power-delay product, of GaAs MESFET with illumination are computed. The computed capacitance and transconductance are compared with the experimentally obtained values and are found to be in fair agreement. Based on these results, the design considerations for an optically controlled MESFET switch are discussed. Finally, variation in device parameter due to optical illumination and its effect on the cutoff frequencies f/sub T/ and f/sub max/ are also investigated.     

Measurements of device parameters for Nd:YAlO3lasers

This paper presents measurements of several properties of Nd:YAlO3useful in the design of laser devices. Values for the gains, cross sections, and saturation parameter of the4F_{3/2} rightarrow 4I_{11/2}transitions are presented for principal axis polarizations. Thermal focal lengths, spherical aberration, and astigmatism forA-, B-, andC-axis rodsfrac{1}{4}in in diameter and 3 in long are shown as a function of input power. Pumping efficiencies with krypton and xenon lamps are compared for Nd:YAG, Nd:Cr:YAlO3, and Nd: YAlO3both in the CW and flash-pumped modes. Finally, the effects of varying the Nd concentration in YAlO3from 0.4 to 1.15 percent are discussed.     

New direct optical pump schemes for multiatmosphere CO2and N2O lasers

Nine schemes for direct optical pumping of multiatmosphere CO₂ and N₂O lasers at pump wavelengths in the 1.4-3.6-μm region are discussed. Most of these wavelengths can be generated by solid-state lasers, which are more attractive pump sources than the chemical lasers (HBr, HF) used previously to pump high-pressure CO₂ and N₂O lasers. Including previously studied pump schemes, there are altogether 14 possible pump transitions in CO ₂ and N₂O in the 1.4-4.5-μm region. Numerical laser simulations are carried out to compare all of these pump schemes. Assuming 10 J/cm² pump energy in a pulse of 100 ns FWHM, and 5% output coupling as the only resonator loss, the calculated energy conversion efficiencies are in the range of 6-40%. The pump thresholds are in the range of 0.1-3.1 J/cm²