Micro FET pressure sensor manufactured using CMOS-MEMS technique

The fabrication of a micro field effect transistor (FET) pressure sensor using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process has been investigated. The pressure sensor is composed of 16 sensing cells in parallel, and each sensing cell includes a suspended membrane and an NMOS. The suspended membrane is the movable gate of the NMOS. The pressure sensor needs a post-process to obtain the suspended membrane after the CMOS process. The post-process employs etchants to etch the sacrificial layers to release the suspended membrane, and then a low-pressure chemical vapor deposition (LPCVD) parylene is used to seal the etching holes in the pressure sensor. The pressure sensor produces a change in current when applying a pressure to the sensing cells. Experimental results show that the pressure sensor has a sensitivity of 0.022 μA/kPa in the pressure range of 0–500 kPa.     

基于小波神经网络的电动机变频系统故障检测的研究

文章提出应用小波分析技术提取故障特征并以模糊神经网络进行故障预测.由此建立了基于小波与神经网络的电动机变频调速故障的智能检测系统,并用MATLAB进行仿真,证明了该方法对电动机变频系统故障的检测是有可行性的.     

Knowledge Creation Systems in Seven-Eleven Japan

Japanese convenience store chain Seven-Eleven Japan (hereinafter "SEJ") has been profitable for 30 years by constantly anticipating changing trends regardless of the severe business environment. In this paper, the knowledge creation process and its supportive systems in SEJ to examine how information system can support knowledge creation are described. Using case study method, the knowledge creation theory is applied to SEJ, and the results show that facilitating "dialogue" and reinforcing "creative routine" might be the most important functions of information system to support knowledge creation.     

PLC控制技术在反渗透水处理中的应用

本文介绍了一套反渗透水处理系统的设计方案,着重叙述了预处理和反渗透工艺和控制功能.为了保证系统的可靠性和操作性,系统采用PLC、触摸屏和工控机组成的控制系统.控制程序采用模块化的设计方法,这种方法易于理解和编程,同时介绍了顺序功能图编程法在恒压供水控制中的应用.     

镁合金表面铬掺杂类金刚石薄膜的制备与性能研究

本文利用阳极层离子束混合磁控溅射技术在AZ31镁合金表面制备了类金刚石涂层（DLC）和Cr掺杂DLC膜（Cr-DLC）,并利用Raman光谱、残余应力仪、划痕仪、摩擦磨损仪和电化学工作站等,对薄膜的碳结构、残余应力、结合力、摩擦学性能和耐腐蚀性进行了研究。结果表明：相比纯DLC膜,Cr-DLC膜具有较低的残余应力,较高的膜/基结合力。Cr-DLC膜能显著提高镁合金的抗摩擦磨损性能,但对改善镁合金耐腐蚀性能影响不大。     

High-performance polythiophene thin-film transistors with nematic liquid crystal modification

The influence of nematic liquid crystal molecules on the electrical properties and microstructure of polymer semiconductors poly(3-hexylthiophene) (P3HT) was investigated. It was found that the introduction of nematic liquid crystal molecules can significantly improve the performance of P3HT thin-film transistors, providing better electrical characteristics and enhanced mobility. The field-effect mobility of the device with liquid crystal modification can be enhanced by up to a factor of ten with respect to that of the pure P3HT device. UV–visible absorption spectroscopy, X-ray diffraction, and atomic force microscopy measurements show that the enhancement of charge-carrier mobility is achieved through a more highly organized morphology and a reduction in the density of traps presents in the P3HT/liquid crystal structure. The results shown here therefore illustrate a high-performance solution-processable thin-film transistors, which is quite feasible and can pave a key step for the practical applications of organic electronic devices.     

基于LM5117P的降压型直流开关稳压电源设计

降压型直流开关稳压电源是一种单向DC-DC变换器,实现稳定直流降压功能.本系统采用同步降压控制器LM5117P作为电路控制核心,以同步Buck电路作为降压主电路,通过闭环回路反馈设计以及芯片本身的精准采样,将输入电压16V降为5V恒压输出.     

B/S架构的气象资料综合监控平台建设

本系统主要是对省级收集的各类下行资料进行检索、实时信息采集、入库、补调、监控,并全面、实时、准确地提供各类资料的详细信息,达到了对实时资料的高效管理和实时监控的目的.本系统的建成实现了云南省气象资料的全面网络化管理,实现网上工作,减轻值班人员劳动强度,提高工作效率.     

接触热阻对薄板零件表面激光淬火温度场形成影响研究

激光淬火工艺具有节能环保、质量高的优点。研究薄板零件激光淬火时所形成的温度场对将激光淬火应用于薄板零件表面强化的实际工作中具有重要的作用。本文通过对45钢和铸铁HT250之间接触面的接触热阻进行实验测试,通过数据分析得出了相应的接触热阻经验关系式。利用Abaqus软件模拟薄板表面激光淬火,其中将实验所得的接触热阻经验关系式代入,得到了相应薄板表面淬火温度场。通过与不考虑接触热阻的零件表面淬火温度场仿真结果进行对比,得出了接触热阻对薄板零件表面激光淬火所形成的温度场的影响。研究成果可对薄板表面激光淬火工艺应用于实践提供指导。     

A Rapid Code Acquisition Scheme for DS/SS Systems

In this paper, we propose a rapid code acquisition scheme for direct-sequence spread-spectrum (DS/SS) system basing on the improved seed accumulation of sequential estimation (ISASE). This method solves the problem that SASE scheme cannot work in the presence of carrier-frequency offset. The mean acquisition time of the ISASE scheme is derived by the generating function flow graph technique, and the tolerance of carrier-frequency offset is obtained in a closed-form expression. The performance of the proposed acquisition scheme is analytically evaluated in terms of the mean acquisition time. Analysis in theory and numerical results show that the proposed scheme yields improvement of the mean acquisition time over the RASE scheme by a factor of 2–15 times for the PN} period more than 255 in normal operating condition. For the important parameter-accumulating number m, we recommend to choose from 5 to 20 through the tradeoff of the tolerance of carrier-frequency offset and acquisition speed. Jiachi Wang was born in September, 1971. He is a Phd candidate in department Electronics and Information Engineering, Huazhong University of Science and Technology. His research areas include spread spectrum and digital communication, and digital signal processing. Xiulin Hu was born in 1945. He is a professor and Phd advisor in department Electronics and Information Engineering, Huazhong University of Science and Technology. His research areas include spread spectrum and digital communication. Yunyu Zhang was born in 1948. She is a professor in department Electronics and Information Engineering, Huazhong University of Science and Technology. Her research areas include software radio and digital communication. Qingyun Dai was born in 1977. She is a Phd candidate in department of Electronics and Information Engineering, Huazhong University of Science and Technology. Her research areas is wireless network.