通用可靠的串口/以太网网关设计

介绍了一种串口/以太网嵌入式网关的设计方案,详细讨论了串口可靠通信的实现方法,并在开源操作系统RT-Thread和微处理器S3C2440开发板的软硬件平台上实现。网关实际应用于一个无线传感器网络项目,实验表明该网关能实现可靠的数据通信。     

Gain‐scheduled dynamic output feedback control for discrete‐time LPV systems

This paper presents synthesis conditions for the design of gain‐scheduled dynamic output feedback controllers for discrete‐time linear parameter‐varying systems. The state‐space matrix representation of the plant and of the controller can have a homogeneous polynomial dependency of arbitrary degree on the scheduling parameter. As an immediate extension, conditions for the synthesis of a multiobjective ??_∞ and ??₂ gain‐scheduled dynamic feedback controller are also provided. The scheduling parameters vary inside a polytope and are assumed to be a priori unknown, but measured in real‐time. If bounds on the rate of parameter variation are known, they can be taken into account, providing less conservative results. The geometric properties of the uncertainty domain are exploited to derive finite sets of linear matrix inequalities based on the existence of a homogeneous polynomially parameter‐dependent Lyapunov function. An application of the control design to a realistic engineering problem illustrates the benefits of the proposed approach. Copyright © 2011 John Wiley & Sons, Ltd.     

Chord-PKI: A distributed trust infrastructure based on P2P networks

Many P2P applications require security services such as privacy, anonymity, authentication, and non-repudiation. Such services could be provided through a hierarchical Public Key Infrastructure. However, P2P networks are usually Internet-scale distributed systems comprised of nodes with an undetermined trust level, thus making hierarchical solutions unrealistic. In this paper, we propose Chord-PKI, a distributed PKI architecture which is build upon the Chord overlay network, in order to provide security services for P2P applications. Our solution distributes the functionality of a PKI across the peers by using threshold cryptography and proactive updating. We analyze the security of the proposed infrastructure and through simulations we evaluate its performance for various scenarios of untrusted node distributions.     

基于GPRS和Web远程管理系统的设备监控终端设计

以STC12C5A32S2为核心,基于GPRS无线通信网络和Web远程控制技术,设计了一套设备监控系统终端,实现对被监控设备进行远程监控与数据采集,将数据上传至远端的Web管理系统进行数据管理,解决了对大量终端设备的远程实时监控和通信问题。     

Solid-liquid phase equilibria of benzene + 2-methyl-2-propanol system under high pressures

Solid-liquid phase equilibria of the benzene + 2-methyl-2-propanol system have been investigated at temperatures from 278 to 323 K and pressures up to 300 MPa using a high-pressure optical vessel. The uncertainties of the measurements of temperature, pressure and composition are within ±0.1 K, ±0.5 MPa, and ±0.001 mole fraction, respectively. The freezing pressure at a constant composition increases monotonously with pressure. The eutectic point shifts to a higher temperature and benzene-rich composition with increasing pressure. In order to describe the pressure-temperature-composition relation of high-pressure solid-liquid phase equilibria, a new simple equation has been proposed as follows:

单晶硅化物及其应用

本文评述了单晶CoSi_2和NiSi_2的结构特点、各种制备方法、器件应用和发展前景。采用分子束外延(MBE)和“内延”法(Mesotaxy)制备的单晶硅化物质量,电学性能和热稳定性较好。由于首次得到理想的突变的金属——半导体接触,使对金属——半导体接触的理论分析成为可能。硅/单晶硅化物/硅结构在实际应用中非常重要,如单晶硅化物作集电极埋层,能降低集电极串联电阻,克服重掺杂埋层的横扩和自掺杂问题,提高了电路工作速度,减小了器件面积。埋层硅化物也可作为微波传输线的地线,是实现高频集成电路互连的好方法。而采用该结构制备的高速器件——金属基区晶体管(MBT)和穿透基区晶体管(PBT),具有很好的应用前景。     

封闭循环TEA CO2激光器用催化剂的实验研究

在不同的催化剂和不同温度的条件下,用磁氧分析仪监测了封离型TEA C0₂激光器中O₂含量随时间或脉冲次数的变化。对实验现象进行了分析。对几种催化剂的特性给出了详细的比较。     

基于增量式PID算法的帆板控制系统的设计

基于STC12C5A60S2单片机与增量式PID算法,实现对帆板系统的控制。该系统主要由键盘模块、显示模块、风扇驱动模块、角度测量模块、报警模块组成。角度传感器测量帆板的角度并反馈回单片机,通过增量式PID算法计算,并由PWM方法控制风扇的转速,从而实现精确控制风扇风力与帆板角度。