基于嵌入式的无线条码扫描仪系统的设计

传统有线条码扫描仪受数据线长度的影响,而市场上的无线条码扫描仪无线通信距离一般在30~100 m范围内,在使用范围和用途上造成一些限制。提出一种基于嵌入式的无线扫描系统的设计,其最大无线通信距离为800 m。该设计采用Philips公司的LPC2142 ARM嵌入式芯片和ADI公司的ADF7020无线收发芯片。LPC2142接收条码扫描仪采集的数据并进行处理,ADF7020完成无线数据发送接收。     

提高彩色PDP显示灰度等级的准延伸编码方法

为了解决延伸编码在消除动态假轮廓时存在显示灰度等级不够和需要子场数目多的不足 ,从动态假轮廓的成因入手 ,吸取延伸编码和常规编码的长处 ,提出了准延伸编码方法 ,该方法能够使用较少的子场数目来提高PDP的显示灰度等级 ,同时有效地消除了动态假轮廓现象。仿真结果表明 ,采用准延伸编码方法 ,运动图像和静止图像的相关系数为 0 8972 ,使图像显示质量大为改善     

对帧校验序列的研究

本研究对 FCS的几种主要实现方式及其检错性能进行了数学分析及研究。并对数据比特长度与检验比特长度的关系进行了讨论     

一种多重加密的算法及其实现方案

提出一种多重加密的算法.针对以8 bit为一字节的数据格式提出了一种实现的方案.在此基础上加入码字分割技术,从而提出了一种改进的方案.并分析和比较了两个方案的加密效能.     

水工混凝土"78规范"与"96规范"安全度对比

该文从规范采用的设计准则和混凝土强度保证率人手，分别对SDJ20-78和SL／T-96两个水工钢筋混凝土结构设计规范有效版本的安全度进行了分析，并以轴心受压杆件和受弯杆件为例，量化了两本规范的安全度对比情况以及对工程量的影响程度。     

汽车电子控制自诊断系统

汽车技术的发展愈来愈呈现出电子化的趋势，传统的维修诊断方式巳远远不能满足汽车技术飞速发展的步伐。本文对汽车电子控制自诊断系统进行了深入的阐述。     

Power Allocation and Control in Multimedia CDMA Wireless Systems

This paper proposes an analysis of outage performance of a Direct Sequence-Code Division Multiple Access (DS-CDMA) wireless system with heterogeneous traffic. Imperfections in closed-loop power control and the activity characteristics of any traffic source in the system are taken into account. For given requirements of signal-to-(noise + interference) ratio and outage probability of every user in the system, the system capacity is derived in terms of the maximum number of users of each class that can be accomodated. The optimization problem is explicitly solved for a system consisting of a single cell and an approach is outlined for solving the optimization problem in a multi-cell system. The analysis is carried out by resorting to various approximations of Multiple Access Interference (MAI), that require different methods for solving the optimization problem and yield different degrees of accuracy. From numerical results it is seen that optimal power allocation is essential to limit the effects of power control imperfections, mainly in the case of non uniform amplitudes of residual power fluctuations. In the second part of the paper, a performance study of fixed step closed-loop power control algorithms is presented. A detailed simulation of the power control loop evidences that fast fading phenomena can not be easily tracked, even at moderate Doppler spread. Statistics of residual power fluctuations are estimated and can be used to support the assumptions in the first part of the paper. Furthermore, second order statistics of the controlled channel are estimated, and second order outage statistics (average rate and duration of outage events) are derived as a quantitative measure of residual channel burstiness.     

炼油装置设备的紧凑布置

主要介绍了实现设备的紧凑布置并减少装置占地的三种方法:利用装置的联合布置、合理的安全间距、框架式布置。     

Effect of Sr and Ce on Synthesis of Nanometer Perovskite LaMnO3＋λ

Nanometer perovskite LaMnO3 λ, La0.6Ce0.4MnO3 λ and La0.6Sr0.4MnO3 λ were prepared by citric acid-aide dsol-gel method. The effects of Ce, Sr on the structure and properties of nanometer perovskite were studied through DTTGA, XRD, TEM and BET analyses. The results show that, by sol-gel method, LaMnO3 λ, La0.6Ce0.4MnO3 λ and La0.6Sr0.4MnO3 λ were made with average particle size of about 60, 100 and 30 nm, respectively. After partially substituting Sr on La positions in LaMnO3 λ, it is found that Sr is located at the perovskite lattice so as to reduce the formation temperature of the perovskite. As a result, the perovskite has a smaller particle size and larger specific surface area. On the contrary, it is difficult for Ce to enter the perovskite lattice. Ce exists mostly in the form of CeO2 as partially substituting La in LaMnO3 λ. The formation temperature of the perovskite increases, and the catalyst containing CeO2 presents a larger particle size and less specific surface area.     

混沌编码在信息加密中的应用

混沌密码学将非线性动力系统中的混沌理论引入密码学研究。讨论了混沌编码的原理,完成了计算机软件编制,实现了对文字、图像和随机的信息信号的混沌加解密处理。