冰箱换热器性能测试实验台测控系统开发

介绍了冰箱换热器性能测试系统的工作原理、硬件构成和软件功能的实现。基于LabVIEW平台编写的软件完成了对数据采集系统的控制,数据的存储、分析计算和显示。同时,程序接收用户的指令,将指令传送至PLC对系统运行进行控制。实验结果表明,该系统具有控制和测量精度高、自动化程度高、运行稳定可靠、用户界面友好等优点。     

A Rapid and Low-Cost Procedure for Fabrication of Glass Microfluidic Devices

In this paper, we present a simple, rapid, and low-cost procedure for fabricating glass microfluidic chips. This procedure uses commercially available microscopic slides as substrates and a thin layer of AZ 4620 positive photoresist (PR) as an etch mask for fabricating glass microfluidic components, rather than using expensive quartz glasses or Pyrex glasses as substrates and depositing an expensive metal or polysilicon/amorphous silicon layer as etch masks in conventional method. A long hard-baking process is proposed to realize the durable PR mask capable of withstanding a long etching process. In order to remove precipitated particles generated during the etching process, a new recipe of buffered oxide etching with addition of 20% HCl is also reported. A smooth surface microchannel with a depth of more than 110 mum is achieved after 2 h of etching. Meanwhile, a simple, fast, but reliable bonding process based on UV-curable glue has been developed which takes only 10 min to accomplish the efficient sealing of glass chips. The result shows that a high bonding yield (~ 100%) can be easily achieved without the requirement of clean room facilities and programmed high-temperature furnaces. The presented simple fabrication process is suitable for fast prototyping and manufacturing disposable microfluidic devices.     

Vaudeville: A High Performance,Voice Activated Teleconferencing Application

We present Vaudeville, a voice-activated, hands-free, ATM-based video conferencing application. This system is scalable; although video bandwidth is normally a limiting factor in the number of conferences participants, the bandwidth attributed to the video is not a function of conference size. This is achieved through an automatic, distributed floor control mechanism that gives the appearance of an open floor. Audio and video are encoded in hardware using a platform-independent, ATM hardware multimedia interface. Vaudeville features digitally transmitted NTSC video, voice-activated audio transmission, audio bridging of two audio streams, and voice-activated video switching. Multiple simultaneous multiparty conferences are supported. Users can move freely among conferences without knowledge of the underlying network structure. We describe how Vaudeville was built using a component-based distributed programming environment. We also describe the algorithms used to control the audio and video of the application.     

Electrical/Mechanical Modeling, Reliability Assessment, and Fabrication of FlexConnects: A MEMS-Based Compliant Chip-to-Substrate Interconnect

Compliant free-standing structures can be used as chip-to-substrate interconnects. Such ldquocompliant interconnectsrdquo are a potential solution to the requirements that will be imposed on chip-to-substrate interconnects over the next decade. However, cost of implementation and electrical performance limit compliant interconnects. In our previous work, we have proposed a new compliant interconnect technology called FlexConnect to address these concerns with compliant interconnects. An innovative cost-effective MEMS-based fabrication process is used to fabricate these compliant interconnects. Sequential lithography and electroplating processes with up to two masking steps are utilized. Utilizing the proposed fabrication process, in this paper, FlexConnects are realized at a 100-mum pitch. High-frequency modeling of the electrical parasitics of the interconnect is performed. Through finite-element-based models, the advantage of using multiple electrical paths as part of the interconnect design is shown from a thermomechanical reliability perspective. Finally, taking advantage of the MEMS-based photolithographic fabrication process, a heterogeneous combination of FlexConnects and column interconnects is proposed. This approach is shown to be an additional avenue to attain improved electrical performance without compromising mechanical performance.     

高压氢环境专用薄膜应变片的设计制备及性能测试

为解决普通箔式电阻应变片在高压氢环境中存在应变片脱落、零点漂移和蠕变等问题,设计了一种用于高压氢环境中的专用薄膜应变片,具体制备方式为:利用磁控溅射技术,依次在316L不锈钢基底上镀Cr膜(过渡缓冲层)、AlN膜(绝缘部分)、FeCrAl合金膜(功能层,使用掩模板镀膜为栅丝形状).应变片的测试结果表明:与常规的粘贴型应变片相比,该薄膜应变片消除了在高压氢环境下应变片的零点漂移和蠕变.     

中文网页信息检索测试集的构建、分析及应用

随着WWW的迅速发展,Web信息检索技术成为研究者广泛关注的话题,但缺少合适的测试评测机制制约了中文网页信息检索技术的发展。参考国外测试集的构建经验,我们构建了大规模中文网页信息检索测试集CWT,并组织了SEWM中文网页检索评测,希望在国内外各个研究小组的共同参与下建立并完善CWT,一起推动中文网页信息检索技术的发展。本文在调研和分析国内外现有研究进展的基础上,详细介绍了CWT的构建原则和方法,并对CWT进行了有效的统计分析和实验研究。本文提出的构建测试集的方法为以后的研究提供了参考。     

Design, Fabrication and Control of Spherobot: A Spherical Mobile Robot

In the literature, Spherobot refers to a mobile robot with a spherical exo-skeleton and a propulsion mechanism that uses unbalance masses in a tetrahedral arrangement. A modified design of Spherobot, that is better suited to fabrication, is presented in this paper. The modified propulsion mechanism and other components of the design are discussed in detail to highlight the challenges of fabrication. An adaptive estimation and control algorithm used for position control of the unbalance masses and a steering algorithm used for motion control of Spherobot are also discussed. Experimental results of the Spherobot navigating a hallway with bends is presented.     

A Survey of Software Engineering Practice: Tools, Methods, and Results

The results of a survey of software development practice are reported and analyzed. The problems encountered in various phases of the software life cycle are measured and correlated with characteristics of the responding installations. The use and acceptance of the term "software engineer" is investigated, and the functions and background of persons identified as software engineers are reported. The usage of a wide variety of software engineerilng tools and methods is measured; conclusions are drawn concerning the usefulness of these techniques.     

High TPO/TCO for data storage: policy, algorithm and early practice

Today, the data storage industry faces a rapidly growing volume of data. Adding more primary disk capacity to manage data growth is a costly and non-sustainable strategy. Before investing in new capacity, data managers should rationalize their existing storage infrastructure to maximize the use of existing capacity. There is a growing need for achieving a high ratio of Total Performance of Ownership (TPO) to Total Cost of Ownership (TCO), or TPO/TCO. The storage infrastructure can be made more efficient by assessing data usages, eliminating unnecessary data copies, moving less critical data to less expensive disk devices and repurposing allocated but unused capacity. Optimizing existing storage assets can reduce storage costs by delaying or eliminating the need for new primary capacity to manage information growth. In this paper, we apply the notion of information lifecycle management (ILM) to achieve the above improved efficiencies and optimizations. By balancing data value and storage requirements, we aim to reduce the storage system’s dependence on expensive high-performance disk devices and lower its cost per online gigabyte, thus resulting in a higher TPO/TCO.     

High TPO/TCO for data storage:policy,algorithm and early practice

Today, the data storage industry faces a rapidly growing volume of data. Adding more primary disk capacity to manage data growth is a costly and non-sustainable strategy. Before investing in new capacity, data managers should rationalize their existing storage infrastructure to maximize the use of existing capacity. There is a growing need for achieving a high ratio of Total Performance of Ownership (TPO) to Total Cost of Ownership (TCO), or TPO/TCO. The storage infrastructure can be made more efficient by assessing data usages, eliminating unnecessary data copies, moving less critical data to less expensive disk devices and repurposing allocated but unused capacity. Optimizing existing storage assets can reduce storage costs by delaying or eliminating the need for new primary capacity to manage information growth. In this paper, we apply the notion of information lifecycle management (ILM) to achieve the above improved efficiencies and optimizations. By balancing data value and storage requirements, we aim to reduce the storage system’s dependence on expensive high-performance disk devices and lower its cost per online gigabyte, thus resulting in a higher TPO/TCO.     

Polymeric Thermal Microactuator With Embedded Silicon Skeleton: Part II—Fabrication, Characterization, and Application for 2-DOF Microgripper

This paper presents the fabrication, characterization, and application of a novel silicon-polymer laterally stacked electrothermal microactuator. The actuator consists of a deep silicon skeleton structure with a thin-film aluminum heater on top and filled polymer in the trenches among the vertical silicon parts. The fabrication is based on deep reactive ion etching, aluminum sputtering, SU8 filling, and KOH etching. The actuator is 360 $muhbox{m}$ long, 125 $mu hbox{m}$ wide, and 30 $muhbox{m}$ thick. It generates a large in-plane forward motion up to 9 $muhbox{m}$ at a driving voltage of 2.5 V using low power consumption and low operating temperature. A novel 2-D microgripper based on four such forward actuators is introduced. The microgripper jaws can be moved along both the $x$- and $y$ -axes up to 17 and 11 $muhbox{m}$, respectively. The microgripper can grasp a microobject with a diameter from 6 to 40 $muhbox{m}$ . In addition, the proposed design is suitable for rotation of the clamped object both clockwise and counterclockwise. $hfill$[2007-0192]      

应用于锁相环的低电压高性能电荷泵设计

该文设计采用SMIC1．2V,0．13μmCMOS工艺。通过对电荷泵的非线性特性分析,设计一种低电压,高性能的电荷泵电路。这种电荷泵电路上下支路的电流失配在300mV-900mV的输出摆幅下得到很好的优化,与传统低压结构比较有明显优势,同时设计中也抑制了电荷共享等电学失配。     

CORBA与Web Services应用集成网关的研究与实现

针对CORBA应用在Internet范围内进行数据共享和应用集成的局限性,研究了CORBA与web Services应用集成的方式,设计实现了CORBA／Web Services应用集成网关,深入探讨并初步解决了应用集成中的接口转换、数据类型转化、CORBA对象调用等关键问题。     

过阻尼过程的预测控制及其在工业热处理炉上的应用

针对过阻尼过程,基于简化的脉冲响应模型,提出了一种新的预测控制算法,并且成功地将其应用于工业热处理炉的温度控制中.     

A Wheel-legged Robot with Active Waist Joint: Design,Analysis, and Experimental Results

This paper presents a wheel-legged robot that features an active waist joint. The proposed wheel-legged robot is composed of a front module, a rear module, and an active waist joint. The proposed robot can perform rectilinear motion and turning motion in both wheeled and legged modes. The active waist joint module is added to make the robot pass through the curved narrow channel. Several experiments have been done to evaluate the performance of the proposed wheel-legged robot. The maximum velocities of the proposed robot in wheeled and legged modes are 17.2 and 10.4 m/min respectively. And the average corresponding deflection rates of the proposed robot in wheeled and legged modes are 3.1 and 3.7 % respectively. The mobility efficiencies of the robot in wheeled and legged modes are up to 96.3 and 94.3 % respectively. Compared with the proposed robot in legged mode, the performance in the turning motion with the active waist joint is better when the proposed robot is in wheeled mode. Two approaches of climbing obstacles are proposed for the proposed robot in legged mode. The wheel-legged robot can climb an obstacle with maximum height of 10 cm.     

状态和参数联合估计方法及其在飞行试验中的应用

本文提出了一种有效的状态和参数的联合估计方法.针对参数估计结果有偏或发散的问题,本文给出了一种参数向量可控性模型,并由此模型得到了噪声相关的一种状态和参数的估计方法.运用状态和参数联合估计的新方法进行飞行状态和测量仪器的误差估计,仿真和实际飞行数据处理的结果表明;本文提出的方法可以给出飞行状态和仪器误差估计的满意结果,比普通推广Kalman滤波方法更有效.     

用于高冲击检测硅基三轴集成压阻式MEMS加速度芯片的建模与仿真

主要讨论硅基单芯片集成的三轴压阻式MEMS加速度计芯片的建模与仿真.通过有限元软件ANSYS建立的结构模型可以较好的理解和分析所要设计的加速度芯片在承受任意不同轴向加速度所产生惯性力时的静态表现.利用有限元软件ANSYS我们详细分析了各个悬臂梁在承受不同轴向惯性力时的应力变化,确定出敏感电阻的位置.通过LS-DYNA软...     

用8031，DRAM和高速A/D实现快速数据采集

介绍了一个用８０３１，ＤＲＡＭ和高速Ａ／Ｄ等芯片构成的快速数据采集系统。该系统使Ａ／Ｄ转换的数据不经ＣＰＵ“中转”，而直接存入ＤＲＡＭ中。它具有硬件结构简单、价格低廉、易实现大容量存储等优点。本系统对模拟信号的采集并将采集数据送入存储器的周期为８μｓ。