压电加速度计的结构与其输出灵敏度的关系

在对压电加速度计输出灵敏度的检测中,我们发现中心压缩式结构压电加速度计的输出灵敏度会随着时间的推移有上下波动的现象,而在剪切型结构的压电加速度计中,它的输出灵敏度变化相对要小得多.围绕这一现象,我们展开了理论分析和数据测试,供讨论.     

体硅加工的压电式微加速度计的设计

提出并设计了一种采用体硅微制造工艺制造的压电式微加速度计,其中体硅加工的硅质量块由悬臂梁支撑且悬臂梁部分区域沉积ZnO压电薄膜.通过对压电悬臂梁建立一维解析模型,研究了影响加速度计灵敏度的结构因素.在此基础上,利用有限元方法软件ANSYS设计了实际的微加速度计,并对六种不同的微加速度计结构进行了分析,得到了不同结构微加速度计的工作频率范围及灵敏度结果.     

基于介观压阻效应的硅微加速度计研究

为了突破传统机电转换局限,提高加速度计灵敏度,提出以介观压阻效应为工作原理制作高灵敏度的硅微加速度计,基于这种原理设计并制备了GaAs基加速度计,通过理论分析计算与试验测试,得出该结构在0.1 gn输入下的输出,并对介观压阻灵敏度和压阻灵敏度的量级作出了比较,验证了采用介观压阻效应制作高灵敏度传感器的可行性,为此类加速度计的设计提供参考.     

一种新结构硅微机械压阻加速度计

设计、制造并测试了一种新结构硅微机械压阻加速度计.器件结构是悬臂梁-质量块结构的一种变形.比较硬的主悬臂梁提供了一定的机械强度,并且提供了高谐振频率.微梁很细,检测时微梁沿轴向直拉直压.力敏电阻就扩散在微梁上,质量块很小的挠动就能在微梁上产生很大的应力,输出很大的信号.5 V条件下,灵敏度为14.80 mV/g,谐振频率为994 Hz,分别是传统结构压阻加速度计的2.487倍和2.485倍.加速度计用普通的N型硅片制造,为了刻蚀高深宽比的结构,使用了深反应离子刻蚀(DRIE)工艺.     

压电加速度计结构与其输出灵敏度的关系

在对压电加速度计输出灵敏度的检测中，我们发现中心压缩式结构压电加速度计的输出灵敏度会随着时间的推移有上下波动的现象，而在剪切型结构的压电加速度计中，它的输出灵敏度变化相对要小得多。围绕这一现象，我们展开了理论分析和数据测试，供讨论。     

压阻式微加速度计的结构优化设计

在过去对技术系统的设计优化通常是根据设计者自己的经验，通过改变一个系统参数来分析系统性能。但随着系统参数的日益增加，这种类型的优化变得越来越困难。鉴于此，本文介绍了利用ANSYS软件对压阻式微加速度计进行结构优化的设计的方法，通过对压阻式微加速度计原结构和优化后的结构进行分析比较，加速度计的结构灵敏度提高了一个数量级，输出灵敏度提高了4倍以上。本文也对微加速度传感器的工作原理和有限元优化的相关概念作了简单的介绍。     

一种基于谐振音叉的新型差动式硅微加速度计设计与分析

为提高谐振式加速度计灵敏度、稳定性以及减小加速度计体积,本文提出一种结构新颖的谐振式硅微加速度计。采用一级微杠杆机构对质量块惯性力进行放大,通过一对差动布置的双端固支音叉谐振器的固有频率变化检测惯性力,从而实现对加速度的测量。该加速度计可采用体硅加工工艺,给出了总体工艺流程。采用解析和有限元分析方法对加速度计敏感元件进行了分析,有限元分析结果与解析分析结果相吻合,有限元分析可得加速度计灵敏度为57.4 Hz/gn。分析结果表明该加速度计结构具有高灵敏度、高温度稳定性和小体积等优点。     

介观压阻效应在硅微加速度计中的应用

为了突破传统机电转换局限，提高加速度计灵敏度，提出以介观压阻效应为工作原理制作高灵敏度的硅微加速度计，基于这种原理设计一种四梁岛结构，通过理论分析与仿真计算，得出该结构在lgn输入下的输出，并对介观压阻灵敏度和压阻灵敏度的量级作出了比较，从理论上验证了采用介观压阻效应制作高灵敏度传感器的可行性，为此类加速度计的设计提供参考。     

基于Ansys的压电式四臂加速度计模拟分析

介绍了压电式四臂微加速度计的工作原理,耦合场分析原理以及ANSYS软件在压电分析中的具体应用.以压电式四臂加速度计为例,使用ANSYS软件对其进行了静态,模态等分析,得出了压电层厚度、悬臂厚度、长度对加速度计灵敏度的影响.在模态分析中得出了加速度计的前三阶固有频率和与之对应的振动形态.本文的结果可以直接应用到加速度计结构的优化设计.     

体硅电容式双轴微加速度计的信号检测新方法

在研究体硅电容式双轴加速度计结构部分,分析差分电容检测方法的基础上,提出了一种适合该加速度计的新型信号检测方法,此方法可有效地将两轴的混叠信号分别进行输出。通过HSPICE软件仿真验证了该方法的可行性。且依据0.5μmCMOSN阱工艺参数对总体电路进行模拟仿真,5V单电源供电,微加速度计单轴灵敏度为50mV/gn,频响为2.3kHz,量程为±50gn。     

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。     

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。