模块化数字可编程微小电阻的设计与应用

针对微小电阻测试仪中电阻量值的检定需求,设计了一种基于线性网络的小阻值可变电阻。设计的高准确度线性网络具有较小电阻调节步进;采用高准确度线性网络解决了小电阻步进的问题;选用逐次逼近自适应算法解决了可变电阻静态温漂的问题。为了避免表面气流温度突变带来不稳定,设计了分区域防风罩作为温度缓冲器。检定结果表明,可变电阻达到最大允许误差为±0.3%。满足最大允许误差为±1%的微小电阻测试仪的量值传递及小型化适用性需求。     

应变测试系统分流校准方法设计

为了减小大型应变测试系统中长导线电阻带来的系统误差,提高多种试验切换效率,使系统在测试过程中具有更精确、更高效的特性,提出了一种结合分流校准电路和长导线电阻补偿算法的策略,根据应变片配桥方式和粘贴形态的不同,计算出实际的长导线电阻阻值与应变片静态阻值,采用计算值进行应变补偿取代了传统各种试验前必须使用高精密校准仪器对整个系统进行校准.理论分析及实验结果表明,这种策略能够准确计算出长导线电阻阻值和应变片静态阻值,采用计算值应变补偿效果达到满量程的0.09％以上,满足高精度需求,同时大幅度减小了传统试验前期的校准工作量,增大了试验范围,有效改善了系统测量精度和试验效率.     

Pt电阻温度传感器批量测试系统的信号调理模块的设计

本文介绍了Pt电阻温度传感器批量测试系统信号调理模块的设计,该信号调理模块采用了多通道四线制设计,使用多路电子开关实现了温度传感器的多通道测量.该信号调理模块经过实验测试,可以实现128路的Pt电阻温度传感器测量,并且所测出的Pt电阻温度传感器的阻值的精度能够达到0.03Ω,经此系统所检测的传感器的测温精度达可到0.1℃.     

用于低温环境的铂电阻温度微传感器

目前,铂电阻温度传感器主要应用于73 K(-200℃)以上环境的温度检测。设计了可用于10 K(-263℃)～200 K(-73℃)低温区的铂电阻温度微传感器。铂电阻温度微传感器采用对称的折回型结构,这种结构有效地降低了交流感抗的影响。传感器的敏感薄膜是一层采用磁控直流溅射沉积厚度为200 nm的铂薄膜。采用QD PPMS仪器测试传感器的电阻与温度的变化关系,得出传感器的电阻温度系数(TCR):研制的温度传感器的电阻温度系数在温度高于30K(-243℃)时可达到9980×10-6/K,同时在低于30K(-243℃)的深低温区域TCR也可达到3730×10-6/K。     

矿用变频器LRC滤波器寄生参数影响研究

LRC滤波器寄生参数易引起串并联自谐振,影响滤波器对矿用变频器长线传输系统中电动机端尖峰电压和电压变化率的抑制性能,甚至造成器件烧损,但目前缺少该方面的研究成果。建立了变频器长线传输系统数学模型,在分析LRC滤波器元件寄生效应的基础上,采用频域分析方法研究了寄生参数对LRC滤波器滤波性能的影响,得出结论:LRC滤波器中电阻寄生电感对滤波效果的影响最为突出,导致LRC滤波器滤波性能下降、变频器长线传输系统在阶跃响应过程中超调和震荡问题严重,其他寄生参数的影响微弱。对LRC滤波器电阻寄生电感对滤波性能及变频器长线传输系统动态特性的影响进行了仿真和实验研究,结果表明:LRC滤波器采用铝壳功率电阻时,电动机端电压波形出现失真,上升及下降过程中存在明显的震荡;采用厚膜功率无感电阻可消除因电阻寄生电感引起的系统超调、震荡现象,使LRC滤波器达到较理想的滤波效果。     

变频器及PLC在翻钢机上的应用

本文介绍了采用安川变频器、制动单元、制动电阻及PLC对原翻钢机进行改造的方法，提高了产品质量，达到了节能的效果。     

采用GA的永磁同步电机直接转矩调速

永磁同步电机直接转矩控制受定子电阻变化影响,进而影响调速系统的精度。本文采用遗传算法动态调整直接转矩控制的调速系统控制器参数的策略,使控制器参数及转矩给定值随转速的波动而调整,克服电阻变化引起磁链控制器输出不准确,达到稳定输出转速的目的。该策略在定子电阻变化较大情况下,仍具有高控制精度。仿真结果验证了这一遗传算法永磁同步电机直接转矩控制调速系统控制策略的有效性。     

硅-蓝宝石压力传感器芯片调整电阻的设计

介绍了硅-蓝宝石压力传感器芯片外延硅层上调整电阻的设计和应用,通过设计调整电阻来实现芯片的电桥平衡,达到了调整其输出特性、改善传感器性能、提高芯片适用性的目的。     

基于单片机的智能型电阻分选数值检测仪

针对目前广泛使用的电阻分选仪输出采用简单的电阻分压式，输出电压容易受电源电压的影响，很难保证产品质量达到标准要求，由于检测偏差较大，给用户尤其是要求高精度的用户带来重大安全隐患。为改进这个不足，基于89C51单片机的智能型功能与软件设计，采用受控恒流源作电源，研制了阻值范围分选数值检测仪。它输出精度高（输出电流误差小于0．01%），检测结果准确（检测精度在0．1％以内），电阻范围可通过仪表键盘设定并自动校正。     

微小电阻(10-8Ω)检测技术的研究

本文介绍了微小电阻的测量技术,拟采用数字锁相环技术提取被噪声淹没的有用信号,通过多点测量及数据处理达到测试要求.该测量装置以计算机为核心,配以高精度A/D转换器、低噪声放大器和精密恒流源,对被测电阻上的信号电压进行放大、采样,最后利用数字锁相技术,计算出电阻的值,具有测量时间短,精度高,误差小等特点.已通过MATHCAD仿真试验,证明该方案可行,以及在全国电解铝行业中具有的社会经济效益.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.