交流电渗微泵流速影响因素的研究

影响交流电渗微泵流速的因素很多,如电极参数、驱动信号参数、溶液的导电率等。通过分析非对称电极交流电渗驱动理论,揭示了交流电渗微泵非对称电极表面流速的计算方法。在分析电极表面流速计算方法的基础上,探讨了以上参数对交流电渗微泵流速的影响规律,这对设计非对称电极交流电渗微泵、驱动信号参数的选择及溶液性质的影响具有指导意义。     

基于参数激励法的MEMS陀螺电馈通抑制方法

针对微机电系统(MEMS)陀螺驱动电极和感应电极之间存在寄生电容,导致驱动信号的电馈通,限制了陀螺仪的灵敏度的问题,采用一种新型驱动方式—参数激励法,可以有效改变陀螺的刚度。仿真测试表明,通过调节激励信号的参数(频率、幅度和相位),可以以可控的方式显著地减少电馈通。     

集成微流体测控芯片的研制

设计、研制了集成有微泵、微沟道、微流量传感器、温度传感器的微流体测控芯片.采用有限元软件ANSYS模拟分析了将其作为冷却芯片时微沟道的散热作用,分析确定了芯片上各元件的结构.该集成芯片为硅-玻璃结构,在硅片上,利用ICP法刻蚀无阀微泵泵体和微沟道;在7740玻璃片上,以溅射、剥离法制作微流量和温度传感器;图形精确对准后硅/玻璃以静电键合方法封接.无阀微泵采用压电元件驱动.测试结果表明:集成芯片具有冷却功能,循环水的流速最大可达25.4mm/s.     

磁力驱动微泵设计及优化

为提高收缩/扩散管无阀微泵的性能,设计了磁力驱动式无阀微泵,并利用ANSYS软件对微泵的整流部件收缩/扩散管和单腔微泵整体结构进行流体仿真,得到了微泵的结构优化参数.仿真和实验结果表明,流量随着管长、最小宽度、扩张角、泵腔半径的增大存在极大值.磁驱动微泵的流量在驱动电压12 V、驱动频率为25 Hz时达到最大值.     

基于微生物代谢成分的电化学多参数检测平台微泵设计

本文提出一种基于抗生素作用下的微生物膜阻抗及代谢液微量残留物分析的电化学并行检测平台,从量化角度实时反映抗生素对微生物的膜贴附变化及代谢成分的影响。根据现有抗生素电化学检测单元的检测精度,待测生理溶液的进样体积需控制在20μL/min~100μL/min,因此本文针对平台中的关键部分———微泵单元采用有限元设计方法进行了静力场、动力场和流体场的综合分析,确保微泵工作流量的精确性和可控性。分析结果得到设计的微泵在施加20 Hz,±40 V驱动电压时的流量为52.864μL/min,并得出流量与电压及频率的关系式来控制流量的变化;在该基础上对微泵被动阀做了力学特性分析与优化设计,分析得出阀臂固支端优化尺寸为0.4 mm×0.5 mm;最后以商用PSS20型微泵为仿真对象做了相关验证性实验,得到仿真流量的误差率为6.7%,验证了本方法的可行性和准确性,为后期微泵的制作、改进以及多参数检测平台的搭建提供了良好的设计参考。     

基于微电极的交流电热效应粒子驱动理论与仿真分析

交流电热效应对实现微流体的驱动和微流体中粒子的操控具有便捷高效等优势。采用对称、非对称平面电极、对称双面电极及螺旋叉指电极，利用有限元方法对其电场、温度场、流场和粒子浓度场进行了强耦合仿真计算，并分析了所施加电压和电导率对局部流速及温度梯度的影响。进而，比较了不同几何类型叉指电极在相同激励下对微流体的驱动能力。结果表明，在只改变电压或电导率的情况下，电压与局部流速及温度梯度的平方成正比，电导率与局部流速及温度梯度呈线性关系；在相同激励下，四种叉指电极的局部流速和温度梯度大小依次为非对称电极、对称电极、双面电极和螺旋电极。实现了对多种典型几何形式微电极的交流电热效应仿真分析，可为优化利用该效应及相关的生物传感器设计提供参考。     

驱动信号对电容式传感器特性的影响分析

在电容检测中,交流电压驱动常常是测量电容变化的必要手段。驱动电压引起作用于可动电极上的静电力,从而影响到可动电极的运动。因此,交流电压的静电驱动势必影响测量的范围和精度。本文详细地分析了由交流电压引起的静电驱动力对微机械结构表态位移特性的影响,并以电容式加速度传感器为例,分单边驱动和双边驱动两种情况,推导出可动电极的运动微分方程。运用近似和图解的方法分另在特殊和一般的情况下求解方程,得到静电驱动电     

新型压电微泵的结构设计与理论分析

微泵在微流控化学分析芯片中有很大的应用前景,日益成为人们研究的热点。从结构设计、理论分析和工艺加工3个方面研究了微阀与微泵,设计出用压电驱动和聚二甲基硅氧烷(PDMS)作为泵膜的集成微阀与微泵,其特点是原理新颖、结构简单、易于加工、操作方便。结构主要是由PDMS泵膜、硅片和压电驱动器组成,其中,PDMS既是泵膜和缓冲单元,也是主动阀片。在直流电压的驱动下,其工作状态是微阀,阻止流体的单向流通,在方波信号的驱动下,其工作状态是微泵,实现流体的吸入与泵出。给出各种几何参数、工作原理和工艺流程。     

水下球形机器人推进器管道的设计和优化

根据水下球形机器人的设计需要,运用CFD(computational fluid dynamics)技术,对不同流态下不同截面尺寸和曲率半径的矩形截面弯管内的黏性流动进行了数值模拟.研究了离心力作用下二次流强度和壁面黏滞阻力随弯管参数变化的情况,得出了截面宽高比为0.75的弯管的水力损失最小的结论,并对该截面形状的弯管的流动结构进行了分析.最后,在标准试验平台上运用涡量探头对出口截面的涡流强度进行了测量,从而证明了数值模拟的正确性,并通过对比分析,完成了水下球形机器人的管道设计和优化.     

基于MEMS工艺的NO2气体传感器研制

设计了一种基于微机电系统(MEMS)工艺的以氧化钨(WO3)为敏感材料的微结构气体传感器,并从半导体理论解释了WO3对二氧化氮(NO2)的敏感机理.气体传感器芯片尺寸为1.3mm ×1.3mm,微热板的有效面积为0.4mm ×0.4 mm.实验结果表明:设计的气体传感器对NO2气体表现出良好的响应,在最佳工作温度下(140℃)功耗为23 mW,最低检测限达50×10-9,响应时间为60 s,恢复时间为180 s.     

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.     

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。     

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。     

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.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere.