基于USB总线的温度测试系统设计与实现

通用串行总线（USB）主要用于外围设备和PC机之间的连接，由于它具有热拔插、自动探测、传输率高等优点，现已逐渐应用于虚拟仪器的通信接口。采用CP2101桥接器，设计和实现了基于USB接口的温度测试系统，重点介绍了硬件及其相关软件的设计。     

用C++ Builder6.0实现AVR单片机与PC机的串行通讯

介绍工业应用中常用的基于Windows异步串行通讯程序开发方法。结合开发实践讨论用C Builder6. 0实现基于AVR单片机与PC机的数据通讯方法,并给出程序设计的一般步骤和详细解释。最后讨论了工程实践中常遇到的通讯方式方法的选择、初始化、校验和数据的保存方法。     

基于SolidWorks的零件系列化设计

介绍了SolidWorks软件在机械零件系列化设计中的应用。采用该软件使系列化设计过程变得简单、重复性工作少，从而提高了设计人员的效率。     

The effect of a headwater dam on the use of leaf bags by invertebrate communities

Breakdown rates and colonisation of leaves from four tree or scrub species differing in quality are studied upstream and downstream of the Canales reservoir, a dam located in the headwater of the River Genil, Sierra Nevada, in southern Spain. This dam, with hypolimnetic release, displays short‐term fluctuations of discharge and nutrient enrichment in the tailwater during the study period. Breakdown rates of the four leaf species studied do not differ between sites, despite the higher dissolved nutrient concentration in the tailwater. This lack of differences is attributed to the potentially high physical breakage of leaves during peak flows that are of higher magnitude at the upstream site. The invertebrate density in leaf bags does not differ between sites, and Chironomidae and Ephemeroptera are the numerically dominant taxa at both sites. With regard to functional feeding groups, the scarcity and lack of significant differences between sites for shredders do not match the trend predicted by the Serial Discontinuity Concept in relation to the effect of a headwater dam. Possibly, the discharge fluctuations at both sites causes excessive instability of the natural substrate (leaf litter) for the shredder guild. However, as expected, the biomass of collectors colonising leaf bags is significantly higher at the tailwater, which might be explained not in terms of quantity, but as a consequence of the higher nutritional quality of the fine particulate organic matter (FPOM) accumulated in leaf bags at this site, owing to the eutrophication caused by the dam. Despite the scarcity of functional shredders at both sites, at the community level, the leaf material is significantly more ingested at the upstream site, suggesting the importance of this source of nutrition for the trophic web at this site in contrast with the tailwater, as predicted by the Serial Discontinuity Concept. This also suggests that caution is needed in using functional feeding groups as trophic guilds to infer system‐level trophic dynamics in streams, given the prevalence of generalist feeders among benthic macroinvertebrates in these environments. Copyright © 2000 John Wiley & Sons, Ltd.     

高、低渗"串联"气层供气机理物理模拟研究

在国内低渗气田开发过程中,对非均质气层（近井高渗、外围低渗）供气机理认识还存在许多问题。利用物理模拟技术,结合苏里格气田单井地质模型,建立了平面均质高、低渗气层“串联”物理模拟模型（“串联”模型）及实验方法,模拟研究了衰竭开发过程中非均质气层压力和产量变化规律、单井生产动态特征和配产对稳产期产气量的影响。     

计算机远控数据采集系统设计

叙述了一个采用分级分布式控制结构实现远程数据采集的无损检测系统的设计过程，涉及系统应用需求选择的硬件配置，两级计算机通信的实现，RS-485接口电路设计等，该系统已投入使用，性能稳定，运行可靠，满足实时性和控制精度要求，可供同行业系统设计者参考。     

基于RS-485通信网络的集成DNC系统研究

集成NDC扩展了传统的DNC的管理功能以实现与DNC系统外的信息集成,文章应用研华ADAM4000系列模块构建RS－485通信网络,建立了一个基于RS－485通信网络的集成DNC系统,文中对RS－485通信网络的构建方法,网络协议,集成DNC系统的车间控制结构,系统功能和系统实现等进行了详细的讨论,该系统成功地应用于国家“863”计划CIMS主题重点应用工程金城JC－CIMS二期工程。     

24位模/数转换器CS5532及其应用

CS5532是一种低噪声24位△-∑型A/D转换器，文中详细阐述了CS5532的结构、组成、功能特点及工作方式，并以高精度称重仪-渗碳液体流量监控仪为例，论述了其在高精度测量方面的具体应用，给出了其与单片机接口的电路原理图和驱动软件程序。     

一种新型的可编程的4～20 mA二线制变送器XTR108及其应用

XTR108是一个完整的可编程的4－20mA两线制变送器芯片，其最大特点是允许用户数字化调节增益、偏移及线性化校正系数等。用户通过主机上的软件界面，经基于单片机组成的标准串行数字接口部件，即可对模拟信号路径进行数字校零校落，对传感器的非线性误差可方便地进行数字化补偿。简要介绍了XTR108芯片的特性、内部结构及其工作原理，对XTR108在铂电阻温度变送器的应用及数字校正方法进行了介绍，并给出了软件设计流程图及用软件模拟SPI总线时序对XTR108执行写操作的程序。     

串行通信收发电路的可靠驱动研究

本文来自于实际工程应用,在串行通信收发电路中,加LED发光二极管作为收发指示灯时,如果直接驱动LED将会导致通信过程的不可靠甚至不可实现.本文针对该问题进行了分析研究,提出了解决方案,对原电路和改后可靠驱动电路的性能进行了理论分析和计算,并且实际测量了改动前后收发信号的波形,论证了解决方案的可行性.