一种光纤电压传感器的设计和性能研究

基于电光晶体的光学电压传感器由于其器件的加工和装配工艺都比较复杂,限制了其应用.本文设计了一种简易的基于BGO晶体电光效应的光纤电压传感器传感头结构,虽然牺牲了一定的精度,但可大大降低加工和装配的难度.对此结构的稳定性和准确度进行了分析,并利用虚拟仪器测试系统,对制作的光纤电压传感器的实验原型的性能进行了测试,结果表明系统的准确度和稳定性已基本达到设计要求.     

高压电力系统中的光纤电压传感器

本文提出了基于石英晶体反压电效应和基于单模光纤光弹效应的两种用于高压电力系统的光纤电压传感器。前者利用电场的线积分测量高电压（≥420kV），后者利用光弹铲应引起的相位差与压电晶体外加电压成比例的关系来测量电压，不受温度和振动的影响。     

高压近电预警用工频电场传感单元设计与分析

由于感应极板电容存在的边缘效应,测量时会引起电力线的畸变,影响灵敏度、线性度和量程等性能参数。提出一种新型带等位环的印刷电路板(PCB)平板电容的交变电场传感单元结构,通过仿真优化分析和设计了带等位环的电场感应单元的结构参数,减小了由于电容极板边缘效应引起的电场畸变。根据工频电场测量标准,对传感单元进行了性能测试。结果表明:等位环结构避免了极板的边缘效应,通过合理配置积分采样电容,使得感应传感单元的线性度可达1.602 5%,电压灵敏度系数达到248 mV/(kV/m)。设计的电场传感器达到近电预警测量的要求。     

反射式光纤微位移传感器

依据光纤反射调制原理进行了反射式光纤位移传感检测系统的设计,利用计数器外径千分尺的测头镜面作为反射体和微位移测量工具,详细介绍了微位移测量装置和传感器检测电路。实验表明,在0～2mm范围内检测系统的输出与位移成线性关系,灵敏度为195μV/μm,线性度为±0.5%,适于微位移的测量。     

基于光纤网络的全分布裂缝检测技术研究

提出了一种基于光时域反射技术(OTDR)的全分布式光纤传感网络新型裂缝检测传感器.该传感器可以在不知道混凝土裂缝位置、裂缝与光纤夹角的情况下对裂缝进行监测,检测范围可根据实际需要对传感头进行灵活设计;并对其进行了传感特性试验,结果表明该传感器的最小检测裂缝宽度可达0.05 mm,并根据传感头1#和传感头2#测得的试验数据拟合光纤损耗与裂缝宽度的关系分别为αc1=760(12-ΔL)-1exp(-0.04(ΔL-12)2)、αc2=1 600(12-ΔL)-1exp(-0.04(ΔL-12)2),该实验结果可作为对全分布式光纤传感器进一步研究的参考.     

基于铌酸锂晶体自身角度光偏置的光学电压传感器

提出了一种利用单轴电光晶体自身角度光偏置的新型光学电压传感器,其光学传感单元由夹在两个正交偏振器之间的一个单轴电光晶体组成.与以往利用四分之一波片产生光偏置不同,新型电压传感器利用单轴传感晶体的自然双折射和近轴光束,将传感晶体沿电光双折射主轴方向转动一个小的角度,产生π/2的角度光偏置.因此,可在不需要附加四分之一波片的条件下实现电压的线性传感.利用单块铌酸锂晶体作为传感元件,对0.2 ～ 35 V交流电压进行测量的非线性误差低于1.8%.此外,计算表明基于铌酸锂晶体的π/2角度光偏置的温度漂移率低于普通多级石英波片.新型传感器简化了光学电压传感器结构,降低了成本,并避免了以往传感器中附加四分之一波片对传感器性能的不利影响.     

干涉型光纤微弱直流电场传感器的设计

主要研究了基于Michelson干涉仪的光纤微弱电场传感器的原理,设计并实现了PLZT非线性电致伸缩材料为敏感元件的"工"字型微弱直流电场传感及其探测系统,该系统能较好解决1/f噪声问题.实验结果表明,系统对被测电场具有非常好的线性响应.     

新型石英晶体微天平分子键裂免疫传感器的研制

基于谐振调幅电压激励石英晶体微天平设计了一种分子键裂型生物传感系统.该传感系统通过Arduino控制数字信号发生器DDS 9854产生正弦波以激励9.98 MHz压电石英晶体.采用了自主振荡电路法和被动激励振荡法,在低振幅(2V)下以谐振电路法测定晶体谐振频率,通过高速继电器切换到被动调幅激励电路中,经数控放大器调节不同激励电压实现谐振调幅,增大石英晶体表面的剪切动量,从而实现分子键裂.随着调幅电压的升高,晶体表面物质的动量增加,导致分子键断裂,通过谐振电路频率和调幅电压值在数分钟内可得到晶体表面物质结合强度的信息.将传感系统应用于A型金黄色葡萄球菌细胞壁蛋白(蛋白质A)和免疫球蛋白IgG体系,在调幅电压激励下会抑制二者的结合.同时,在不同激励电压下可区分蛋白质A与IgG的结合强度.     

一种光纤电压传感器的研究

利用BGO(锗酸铋)晶体作传感头的光纤电压传感器,并用偏振光分析法推出了它的数学模型.利用稳频后的He-Ne激光器作为测量光源;采用补偿测量方案消除晶体自然双折射(应力、温度等)引起的误差;讨论了各光学元件粘接方位角误差对测量精度的影响;系统中用间接测量法测量空气的折射率,对测量方程进行实时修正;采用高精度屏蔽电压器和小波分析算法提高系统的信噪比.实验结果表明,其测量电压误差不大于0.92%.     

基于钼酸铅晶体电致旋光效应的光学电压传感器

研究了基于晶体电致旋光效应的光学电压传感器,电压传感元件采用了国产钼酸铅(PbMoO4)晶体。光学电压传感头仅由两块棱镜偏振器和一块钼酸铅晶体组成。实验结果表明此电压传感器具有较大的线性测量范围,例如对50-5000V工频电压测量的非线性误差低于0.2%;当测量100kHz的高频电压并利用锁相放大器检测传感信号时,最小可测量电压幅值为0.5V。此外,实验测量了所用钼酸铅晶体在635nm光波长及工频电压作用时的电致旋光系数,其数值为1.03pm/V。     

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.