基于氧化铝陶瓷的电容式高温压力传感器

氧化铝陶瓷因其稳定的机械性能和高温鲁棒性得到了广泛的应用。文章以LC谐振电路为技术背景,提出了一种基于氧化铝陶瓷的电容式高温压力传感器,并通过厚膜集成工艺技术将一个定值电感与一个可变电容集成在氧化铝陶瓷基板上实现了传感器的制备。对传感器进行高温环境下的压力测试,实验结果表明:传感器能够完成600℃高温环境下1到5 bar范围内压力的原位测试,且在600℃高温环境下传感器的重复性误差,迟滞性误差和零点漂移分别为8.3%,5.05%和3.7%。     

氧化铝陶瓷基无线无源压力传感器的高温性能研究

利用高温烧结陶瓷技术制备了一种基于氧化铝陶瓷的LC谐振式无线无源压力传感器,并通过合理地设计圆柱螺旋天线以及隔热结构,实现了该传感器在高温环境中的无线耦合测试。研究了传感器在不同温度下的阻抗频率特性,分析并探讨了传感器的高温性能。测试结果表明,在29℃(室温)至700℃的温度范围内,测试天线端的最高瞬时温度为188.4℃,保证了传感器高温测试的可靠性。谐振频率对温度的平均变化量为1.314 kHz/℃,两次重复性测试的相对变化量为3.81%,重复性较好。该压力传感器可应用于高温恶劣环境下的压力测试,其高温性能的研究为压力信号的准确读取奠定了良好的基础。     

基于LTCC的无线无源双参数传感器

设计了一个基于低温共烧陶瓷(LTCC)技术的无线无源双参数传感器,传感器基于LC(inductor-Capacitor)谐振原理,询问天线通过无线遥测的方式获取传感器的压力和温度信号.在传感器基板上集成了两个LC谐振回路,谐振回路中两个电容分别对压力和温度参数敏感,同时两电感采用特殊结构来减少双参数在测试时的互感串扰.搭建了温度-压力复合测试平台,对传感器进行了相关测试.传感器最高测试温度为300 ℃,温度灵敏度为-14.27 kHz/℃,压力灵敏-13.75 kHz/kPa,实验结果表明,这种设计能明显减少两参数之间的互感影响.     

基于LTCC技术的电容式无源压力传感器制备

因陶瓷有稳定的电特性、机械鲁棒性和化学惰性而得到广泛的应用.为了实现高温、高压、潮湿等恶劣环境中的压力测试,以一种陶瓷和耐高温导电浆料为基质,采用低温共烧陶瓷(LTCC)工艺技术和非接触无线传输设计方法实现传感器的制备.传感器以LC谐振电路为基本工作原理,通过丝网印刷技术来实现电感、电容、导带等无源器件的安置,并且在空腔中填入碳膜(印刷碳浆料)有效地防止了层压中空腔的坍塌,所制传感器避免了器件的封装,引线外连,为传感器工作于高温、高压、潮湿等恶劣环境中奠定基础.     

一种LC谐振无线无源温度传感器的研究

无线无源传感器在工业领域具有重要的应用。本文设计了一种基于高介电常数陶瓷基板的无线无源LC谐振温度传感器,采用电感耦合的方式无线测试了传感器在不同温度下的特性。测试结果表明所制作的无线无源温度传感器谐振频率为1.2MHz,随着温度的升高其谐振频率线性降低,灵敏度为2.3kHz/℃。本文制作的器件实现了非接触式的温度测量,可以在比较恶劣的环境下使用。     

基于氧化锆功能陶瓷的无源压力传感器的制备与测试

氧化锆功能陶瓷因其稳定的物理特性、机械韧性和高温鲁棒性得到了广泛的应用.从非接触无源信号测试技术的基础研究出发,以LC无源谐振电路为技术背景,提出了采用氧化锆流延生带来实现MEMS压力微结构的设计方案,并通过利用陶瓷生片叠片工艺技术和厚膜印刷技术成功制备了压力传感器.根据电感耦合原理实现了传感器的非接触环境压力测试,通过在最大耦合距离为1 cm的条件下测试获得的压力传感器的灵敏度为7.5 MHz/bar.本传感器有效避免了微器件封装、引线外联的问题,从而为以后压力传感器应用在较高温度环境奠定基础.     

基于低温共烧陶瓷的无线无源传感器设计

设计一种基于低温共烧陶瓷(LTCC)的无线无源压力传感器。电感器和电容器并联组成的LC谐振回路构成传感器的工作电路,采用厚膜工艺完成了平面螺旋电感器和平行板电容器的制备。传感器利用LC谐振回路的谐振频率对不同压力的响应来表征传感器的应变特性,采用2个电感耦合的方式来实现无线检测。测试结果显示:传感器的谐振频率随外加压力的增大而减小,其谐振频率变化对压力的响应灵敏度约为331.70 kHz/bar。     

基于高温烧结氧化铝陶瓷的无线无源温度传感器

通过高温烧结技术获得了总体尺寸为28 mm×28 mm×0.47 mm的氧化铝陶瓷基板,结合厚膜技术在该基板上印刷无源LC串联谐振电路,设计并制备了一种基于氧化铝陶瓷的无线无源温度传感器。在18℃~300℃的温度范围内实现了传感器的无线测试,测试结果表明该温度传感器呈现出了良好的线性特征,线性范围大且非线性误差小,其谐振频率对温度的灵敏度约为2.75 kHz/℃,可应用于高温恶劣环境下的温度检测。     

LC谐振式高温压力传感器高温下信号衰减的研究

基于LC谐振式传感器在高温下的测试随温度升高会发生信号衰减,频带变宽等现象,为了研究影响信号衰减的主要因素,借助于MATLAB软件,在理论上分析各个因素对信号衰减的影响,初步得出传感器寄生电阻是信号衰减的主要原因;最后,通过分别制作电感线圈和电容陶瓷片模型,并在500℃范围内进行测试,发现电感线圈寄生电阻值增加了6.7Ω,极板电容值增加了0.55 pF,因此得出寄生电阻是信号读取衰减的主要原因。     

基于非共烧技术的高温压力传感器设计

设计一种基于氧化锆( ZrO2 )的高温非共烧陶瓷压力传感器.在已有的低温共烧陶瓷( LTCC)工艺的基础上,经过改进采用了高温非共烧技术进行陶瓷传感器的制作.先进行传感器基底的制作,再制作传感器的金属电路部分.这样解决了高温共烧技术中各材料高温烧结热膨胀系数不匹配的问题.传感器信号读取采用两个电感耦合的方式,实现了非接触压力测量.制作的传感器高温环境下力学特性稳定.测试结果显示:传感器的谐振频率随外加压力的增加而减小,其谐振频率变化对压力的响应灵敏度约为491. 10 kHz/bar.     

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。     

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.     

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.     

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     

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.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.