PLC在交流伺服控制系统中的应用

目的为了满足工业生产对控制设备安全可靠性要求;方法通过分析PLC在自由端口模式通信方式下的工作原理,针对西门子S7-200型PLC与ACU串行通信中的难点,以利用其I/O端子采集状态信号进行天线交流控制系统应用为例;结果给出相关的程序设计流程图;结论提出一种有效可行的解决方案,获得良好的经济和运行效益。     

T800/5228A 层合板I 型断裂韧性优化

冷场发射扫描电镜表明,固化5228A/ PAEK 共混体系发生了反应诱导相分离,相形貌依次经历
了海岛-双连续-相反转的演化过程; DMA 试验表明,PAEK 的引入对5228A 基体树脂Tg 略有影响,但基本不
会改变原有树脂体系的使用温度;T800/5228A 经韧化后,在层间内形成了典型的相反转结构,裂纹扩展路径呈
现出波纹状,明显区别于原有的光滑平直裂纹路径,玉型层间断裂韧度(GIC)大幅度提高。     

An anti-image interference quadrature IF architecture for satellite receivers

Since Global Navigation Satellite System（GNSS） signals span a wide range of frequency, wireless signals coming from other communication systems may be aliased and appear as image interference. In quadrature intermediate frequency（IF） receivers, image aliasing due to in-phase and quadrature（I/Q） channel mismatches is always a big problem. I/Q mismatches occur because of gain and phase imbalances between quadrature mixers and capacitor mismatches in analog-to-digital converters（ADC）. As a result, the dynamic range and performance of a receiver are severely degraded. In this paper, several popular receiver architectures are summarized and the image aliasing problem is investigated in detail. Based on this analysis, a low-IF architecture is proposed for a single-chip solution and a novel and feasible anti-image algorithm is investigated. With this anti-image digital processing, the image reject ratio（IRR） can reach approximately above50 dB, which relaxes image rejection specific in front-end circuit designs and allows cheap and highly flexible analog front-end solutions. Simulation and experimental data show that the antiimage algorithm can work effectively, robustly, and steadily.     

基于MPC8245的通用处理器模块的设计

近年来,PowerPC处理器以其多样化功能和优异性能得到各领域广泛应用。为实现通用处理器模块的设计,采用MPC8245处理器、PCI总线架构。处理器模块的硬件资源相对比较单一,通过实际应用表明在操作系统之上加装不同应用软件可用于多种环境,实现数据处理、功能控制、大大减少重复开发需要的各种资源。     

基于局域网的智能家庭网关

为了实现小区的智能化管理，以提高小区管理人员的工作效率和管理水平及小区居民的生活质量，提出了一种基于嵌入式网关的智能家庭网关，采用智能家庭网关并结合以太网技术而构建的小区智能管理系统，实现了对小区家庭的防火、防盗、煤气泄漏、紧急求助报警，水电气三表远程自动抄收，家电远程控制等功能。是真正意义上的网络化、智能化的家庭控制系统。     

虚拟仪器编程基础—VISA标准与应用

比较系统地剖件了ＶＩＳＡ模型内涵及其基本Ｉ／Ｏ服务方式，简要介绍了利用ＶＩＳＡ函数实现虚拟仪器编程的思想与方法，并给出了一个编程实例。     

关于互斥方案决策问题的研究

互斥方案决策时，运用净现值和内部收益率指标，经常遇到结论相矛盾的情况，本文主要应用方案重复法和投资增额评价法解决这一问题。     

Bolometric luminosities and brightness temperatures of BL Lac Objects and FR I radio galaxies

To understand the connection among the subclasses of BL Lac Objects, FR I radio galaxies and Flat spectrum radio quasars (FSRQs), here the correlations of the bolometric luminosities with redshifts and brightness temperatures of these objects are studied. The bolometric luminosities vary linearly with redshifts, but few objects are scattered at high redshift. The bolometric luminosity versus brightness temperature distribution shows a correlation between these two components, except a few scattered objects, mostly RBLs. The bolometric luminosities and brightness temperatures of FR I radio galaxies with low redshift (<0.1) and low spectral index (α_rx < 0.75) are comparable to those of XBLs and those characteristics of FR I radio galaxies, with relatively high redshift (>0.2) and high spectral index, can be comparable with RBLs with low redshift (z < 0.5) and low bolometric luminosity. Those scattered RBLs with high redshifts (z > 0.5) are believed to be in complex environment with companion galaxies, most of these RBLs are still unresolved. The bolometric luminosity and brightness temperature of these scattered RBLs are comparable to those of quasars. The FSRQs are at high redshifts and bolometric luminosities and the brightness temperatures are also high relative to BL Lac Objects. These results support the FRI/BL Lac unification scheme. It suggests that, the FR I radio galaxies may be the parent populations of the BL Lac Objects, but it needs more investigation to confirm the unification of FR I radio galaxies, XBLs and RBLs.     

五自由度位移平台控制系统设计

介绍了一种五自由度位移平台控制系统的设计。该系统为风洞流场中温度、压力等传感器进行测试提供位移平台。采用自行设计的运动控制器,结构简单,控制精确;移植了嵌入式实时操作系统μC／OS-Ⅱ,通过μC／OS-Ⅱ来调度运动控制器的多个任务;采用PC机作为上位机,为用户提供友好的人机界面。     

一种基于Modem的远程文件传输实现方法

提出了一种在Windows环境下Modem通信编程的方法:TAPI和Win32通信API。介绍了如何通过Microsoft的电话应用编程接口(TAPI)控制Modem和通过Win32通信API函数实现串口的异步I/O,建立了串口通信的相应协议,以实现文件传输。应用表明,文件传输方便、可靠,是Modem通信的有效编程方法。