基于CC2431的无线传感器网络节点的设计

CC2431是Chipcon公司新推出的符合Zigbee标准并具有定位功能的无线射频芯片,设计该节点可以为无线传感器网络提供较高质量的硬件定位功能.在简要介绍无线传感器网络及其节点的特征后,详细介绍了CC2431的性能及特征,并结合CC2431的外部接口及电气特性,利用模块化的设计方法定制节点中的各个功能模块,最终实现了集处理器8051与通信模块于一体的基于CC2431的无线传感器网络节点.     

基于CC2431的无线传感器网络节点设计

CC2431是Chipcon公司新推出的符合Zigbee标准并具有定位功能的无线射频芯片,设计该节点可以为无线传感器网络提供较高质量的硬件功能。本文在简要介绍无线传感器网络及其节点的基本原理后,详细介绍了CC2431的性能及特征,并结合CC2431的外部接口及电气特性,设计出一种具有在线下载、调试、仿真和定位功能的无线传感器网络节点。     

基于ZigBee技术的定位系统研究与实现

文中设计了以CC2431无线定位引擎为核心、结合ZigBee参考节点的无线定位系统。实现了ZigBee节点（CC2430/CC2431）的硬件平台,尽可能降低硬件成本和减小设备体积。该系统采用数字RSSI技术,根据接收信号强度和已知参考节点位置准确计算出待测节点的位置,可实现3～5m定位精度和0.25m的分辨率。提出的定位系统满足了低成本、低功耗、高精度的设计要求。     

基于CC2431实现的无线传感器网络定位

无线传感器网络（WSN）中的定位技术是目前该领域研究的热点。对无线传感器网络中常用的定位技术进行了概述,着重分析了基于接收的信号强度指示（RSSI）定位技术的误差来源及减小误差的办法。重点讨论了利用CC2431内嵌的定位引擎实现的无线传感器网络定位功能及其原理,并通过实际测试验证了其定位准确度满足本应用需求,最后对该定位系统的各项性能指标进行了全面的分析总结。     

基于CC2431的无线定位技术研究

以片上系统(SoC)CC2431为核心,以IAR Embedded Workbench7.50及Borland Delphi7为基本的软件开发平台,实现ZigBee无线定位系统.介绍SoC解决方案CC2431的技术特点、无线定位引擎的功能以及使用方法、定位系统的组成、定位的工作流程.通过实验表明该系统的定位误差最小能控制在1 m之内,精度较高,系统性能稳定.     

基于ZigBee的城市公交车定位系统设计

利用无线传感器单片机CC2431和CC2430设计了一个基于ZigBee的公交车无线定位系统。传统的定位都是采用GPS或者GPRS的定位。GPS定位系统设计简单,可以使用免费的定位卫星资源,但是移动台到控制中心的数据传送需要借助其它网络资源;GPRS定位是基于移动蜂窝式通信的定位,使用现有的移动网络,但是带宽低,不利于突发事件的快速处理。本文设计的Zigbee的无线定位系统基于无线单片机CC2431[1],利用CC2431自带的RSSI定位引擎[2],再运用无线自组网[3]进行定位并向控制中心传送定位信息。该系统设计简单,定位精确度高,设备成本低廉,适合现代化城市的公交车系统智能管理。     

基于无线传感器网络的室内定位系统设计

定位是无线传感器网络(WSN)的一项应用技术,定位精度是影响其应用价值的关键因素。文中介绍了一个WSN室内定位测试系统的设计方案,该系统使用TI的CC2431实现定位。简单介绍了RSSI定位原理,详细描述了定位方案的设计。通过实验测试定位误差,重点对不同参考节点数时的定位误差进行对比分析。实验结果显示,通过增加参考节点数量和对采集的RSSI进行滤波处理,可以有效地提高定位精度。     

基于ZigBee技术的填埋场渗漏检测系统研究

介绍填埋场渗漏检测的基本原理.针对便携式渗漏检测仪有线传输的弊端,研究基于ZigBee无线传输的渗漏检测系统,利用CC2431及采用ZigBee协议栈为平台,实现系统数据的无线传输,克服有线传输的局限性,减轻劳动强度.同时利用CC2431的定位引擎可很好地定位渗漏点,通过ZigBee技术将填埋场各个节点的信息与定位引擎计算的坐标传输给终端PC,实现基于ZigBee的填埋场渗漏检测与定位.经现场测试表明该系统满足设计要求.     

基于ZigBee的监狱人员定位跟踪系统的设计

针对目前监狱安防监控系统存在的问题,文章以CC2430／CC2431芯片为系统核心模块,设计了无线定位网络中参考节点、定位节点和网关节点方框图,给出基于RSSI混合定位算法的流程图,设计基于紫蜂（ZigBee）的监狱人员定位跟踪系统,设置监狱人员定位与跟踪轨迹、人数清点和报警等功能。     

基于ZigBee的儿童定位监护系统的设计

针对目前幼儿园儿童安全管理的问题,文章以CC2430/CC2431芯片作为核心系统模块,设计了无线定位网络中的参考节点、定位节点和网关节点原理框图,给出基于RSSI的混合定位算法流程,设计基于Zig Bee的儿童定位监护系统,设置儿童定位与监护、家长安全接送和报警等功能。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.