大位移磁致伸缩传感器的弹性波建模与分析

磁致伸缩位移传感器是一种测量精度高,测量位移大的新型位移传感器.传感器设计涉及多学科交叉,难以建立统一数学模型.以FeGa材料作为磁致伸缩位移传感器的核心波导丝,建立了波导丝材料磁致伸缩弹性波振动模型,波导丝磁机耦合模型和信号检测模型;同时分析了弹性波信号的受限因素,信号衰减特性.在数学模型基础上,搭建磁致伸缩位移传感器系统,设计了扭转波信号检测电路.实验结果表明信号的输出随着传感距离的增加而减小,该模型对大位移磁致伸缩传感器研究有积极意义.     

空芯光子带隙光纤在光纤陀螺中的应用前景

光纤是光纤陀螺的核心器件之一。光纤的性能参数直接决定光纤陀螺的性能。常规硅芯光纤制造工艺比较成熟,但受限于物理条件,＂克尔效应＂、＂瑞利背向散射效应＂、＂法拉第效应＂和＂舒珀效应＂影响比较大。近年来,基于光子带隙效应的导光机制与传输特性制成的在空气中传输光线的空芯光子带隙光纤逐渐应用在光纤陀螺制造中。介绍空芯光子带隙光纤的性能特点,尤其是相比常规硅芯光纤的优势;空芯光子带隙光纤的技术发展潜力;展望其在光纤陀螺中的应用前景。     

空心光子晶体光纤在拉曼光谱仪中的应用

针对拉曼散射是一种弱散射,同时由于空心光子晶体光纤(HC—PCF)能显著增强光与填充介质之间的相互作用,提出将HC—PCF应用到拉曼光谱仪中,利用平面波展开法对HC—PCF的光子带隙与场分布进行模拟分析,探讨了HC—PCF的参数对拉曼散射强度的影响。通过理论研究发现光子晶体光纤可根据实际应用的需要,通过改变光纤的周期结构或包层气孔之间的间距来改变光子带隙,从而可传输不同波段的光。结果表明了HC—PCF在拉曼光谱仪中应用的可行性,为拉曼光谱仪在分子结构检测与分析提供了新的技术方法,也为HC—PCF的应用和研究开拓了广阔前景。     

超磁致伸缩力传感器的模型研究

磁致伸缩逆效应是稀土超磁致伸缩材料的一个重要应用特性,应用磁致伸缩逆效应可以制作超磁致伸缩力传感器,基于能量变分原理,建立了超磁致伸缩力传感器的有限元模型。应用该模型计算了超磁致伸缩力传感器空气隙中的磁感应强度和磁致伸缩棒上施加力的关系,并与实验值进行了比较。计算结果与实验结果符合较好,表明建立的超磁致伸缩力传感器的有限元模型是有效的。     

模糊免疫算法及其在金属磁记忆检测中的应用

将模糊聚类算法原理引入到免疫算法中,形成无监督学习的模糊免疫算法,并基于该算法建立起智能分析模型,对金属磁记忆检测信号特征进行分析。实验表明,基于该算法建立的模型对实验材料的状态识别能够达到较高的准确率。     

基于模糊免疫算法的管道缺陷磁记忆识别

在金属管道的磁记忆检测中,管道缺陷状态的识别普遍是基于单个检测信号特征值来进行分析的。这种方法存在误检率高、可靠性低等问题。为此,构建了一个基于模糊免疫算法的智能识别模型,将磁记忆检测信号多个特征值组合为一个向量,作为识别模型的输入向量,以分析识别管道缺陷的状况。实验表明,该方法能够对管道缺陷进行准确、有效的识别。     

空芯光子带隙光纤在甲烷检测中的应用

本文所提出的新型的全光纤甲烷检测系统是依托空芯光子带隙光纤作为检测气体传感的探头,利用谐波检测技术处理信号的一种甲烷检测方式。旨在正确分析甲烷气体在空芯光子带隙光纤中的扩散特性,从而对传感气室实现优化设计。另外,研究通过实际的试验成果证实利用空芯光子带隙光纤进行甲烷检测具有一定的可行性。     

光子晶体压力传感器研究

介绍了一种新型光子晶体压力传感器,利用压力使光子晶体带隙的变化特性制作压力传感器,提出了通过测量透射光的变化来测量压力的检测方法。结果表明:传感器的测量范围和灵敏度与构成光子晶体的材料特性有关,材料弹性模量小时,灵敏度高;2种材料的弹性模量和泊松比相差大时,测量范围小。该传感器体积小、重量轻。     

基于Arduino的三维磁记忆检测系统设计及试验研究

利用三轴线性霍尔传感器MLX90393制作磁记忆检测探头,基于Arduino硬件开发平台研制金属磁记忆检测系统,以30CrMo材料试件为试验对象,在静载拉伸作用下开展金属磁记忆试验研究,分析磁记忆信号变化规律以及磁记忆信号梯度值与拉伸载荷之间的变化特征.实验结果表明,拉伸过程中试件表面的磁记忆信号切向分量梯度最大值在拉伸载荷达到16 kN时开始明显变化,在23 kN之后急剧增大到0.0425;法向分量梯度最大值在拉伸载荷达到23 kN之后急剧增大到0.55.本系统为铁磁性材料中应力集中的判定和测量提供了一种有效的检测方法.     

高频低压平面变压器磁芯气隙的研究

变压器时常发生磁饱和现象.为防止磁饱和的发生,通常在磁路中加入一段气隙或减少绕组匝数.研究在磁回路中加入气隙来避免磁饱和时,气隙量对高频平面变压器特性参数的影响.以TDK铁氧体设计的高频平面变压器为研究对象,通过理论分析计算出饱和电流和气隙量.在ANSYS中建立3D仿真模型和电路简化模型,改变气隙量,分析高频平面变压器的涡流场、静电场特性以及原副边电压特性,将仿真数据用MATLAB处理后,得出其电气参数变化规律.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

正~~     

Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

正~~     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.