可调谐半导体激光光谱火灾气体探测系统

基于火灾特征气体检测的火灾报警技术被认为是一种有着广阔前景的火灾早期探测手段,特别是利用光学吸收方法的火灾气体探测技术,除了能够提供高灵敏、低误报率的火灾报警外,还能够实现火灾的早期预警.提出了基于可调谐半导体激光吸收光谱技术的火灾气体高灵敏实时检测系统,采用光通信波段光纤耦合近红外分布反馈式(DFB)半导体激光器作为光源,利用两台激光器结合调制频率多路技术实现了火灾标志性气体CO,CO2的同时检测,对CO的最低检测限约为0.00375 mg/m3(3σ),能够满足火灾气体现场检测的需要.     

低功耗CO气体检测报警装置的研制

本文介绍了一种低功耗的基于单片机控制的CO气体检测报警系统.它能够利用系统内化学传感器,对空气中CO气体的浓度进行有效的测量,精度为1ppm.当CO气体浓度达到设定值时,该装置会自动进行声光报警.     

基于LabVIEW的空芯光子晶体光纤CO2气体检测系统

为了实现全光纤型高灵敏度气体在线检测系统,以空芯光子晶体光纤为传感气室,利用CO2气体分子在1 572.48 nm附近吸收谱以及虚拟仪器LabVIEW平台搭建了双光路差分CO2气体近红外检测实验系统。实验中所用空芯光子晶体光纤长度为1.8 m,通过对其两端同时充气,提高了系统响应速度,0.1 MPa下充气过程仅需100 s左右。以标准浓度CO2气体对该系统进行了标定,并对浓度2%、5%、10%和100%的CO2气体进行了测量,结果表明100 min内浓度检测相对误差不超过2%,标准差最大3.32%。气体吸收光程为1.8 m,系统检测灵敏度达到5.981 810-5 W/ppm。     

DSP主控型CO和CH4双路激光气体检测数据采集系统研制

通过精确检测CO和CH4两种气体浓度,对于煤矿企业安全生产和工业过程控制具有重要意义,TDLAS技术是一种实时高精度的气体检测方式,可用于CO和CH4双路气体检测.针对TDLAS型CO和CH4双路气体检测系统,本文设计了一种DSP型双路数据采集系统.激光信号被CO和CH4选频吸收后,光电二极管FD10D将光信号转换为电流信号,微弱电流信号经OPA2387搭建的前置放大电路转换为电压信号,由ADC芯片ADS8330进行数据采集,回传至DSP主控芯片TMS320C6748,处理完成的数据存储至FLASH芯片M25P16,最后将数据实时上传至上位机.经过测试,该系统可以稳定、准确地进行数据采集,并且适配于其他TDLAS型双路气体检测系统.     

基于CAN总线和MSP430的CO红外检测系统设计

提出一种基于CAN总线接口的红外检测系统的设计思路.该检测系统以MSP430超低功耗单片机为核心,采用SM-CO H/M红外线CO气体探测器,结合数字滤波和温度补偿等算法,达到精确测量CO浓度的目的,利用CAN总线接口实现数据的远程传输,同时进行现场和远程监控.     

基于中红外LED的CO2气体浓度检测系统研究

介绍了基于中红外LED的CO2气体浓度检测系统。通过运用差分吸收和相关检测等手段提高系统灵敏度,系统在检测0%～10%CO2浓度条件下,示值误差约为±0.9%。实验结果与理论数据得到良好的吻合,对LED实现气体检测提供了新思路。     

基于V型腔增强吸收光谱技术的一氧化碳检测研究

论文基于光反馈原理及V型增强腔技术,结合量子串级激光器,搭建了CO吸收光谱检测系统.研究并实现了光反馈效应(反馈相位自动可调)、偶数和奇数腔模式效应、激光器阈值电流降低效应.系统有效反射率达到99.979%,在物理长度为47 cm的光腔内实现了4.48 km有效吸收路径.通过自动调节V型腔长,使光谱分辨率从0.005 3 cm~(-1)提高到0.001 1 cm~(-1).通过阿伦方差分析,确定了最高信噪比的积分时间为53 s.气体压强40 torr,温度20°C时,系统对CO(R(6)吸收线)检测准确度及检测极限分别达到(97.79±0.07)%和(0.49±0.04)ppb.也分析和证明了气体压强对CO的峰值吸收强度、检测准确度及检测极限的影响.     

大气CO2含量分布激光雷达监测

为有效地控制温室效应和气候剧变,准确可靠地监测CO2气体的变化就变得十分重要.拉曼雷达测量大气中CO2气体含量是一种技术先进的可靠方法.介绍了利用气体的拉曼散射效应来测量CO2含量分布的拉曼激光雷达,分析了拉曼雷达的基本原理,设计了具体的实验检测系统,介绍了实验系统各工作件参数情况.对拉曼雷达的回波信号的反演方法进行了具体阐述,初步取得了大气中CO2气体含量分布规律,合肥地区的二氧化碳气体含量大约在350～400 ppmv范围内波动.     

采用LPC55S69的CO激光气体检测无线传输系统的研制

CO气体作为一种还原剂在工业冶金等场景中广泛应用,对于CO的检测在工业生产、大气监测、中毒预警中是十分重要的。TDLAS技术能够高效准确地检测特定气体浓度,基于TDLAS技术的CO气体检测相较于传统检测方法优势明显。本设计采用LPC55S69作为主控,VCSEL激光器作为核心光源实现TDLAS的CO气体检测。随着检测环境越加复杂,基于现场检测的方法局限性越来越大,本设计还根据需要,设计了检测数据无线加密传输方式。LPC55S69采用128位AES-ECB算法实现数据加密,并通过WIFI(ESP8266)将数据上传至PC端,PC端进行解密后得到待测气体浓度信息。该方法实现的远程数据加密传输大大扩宽了TDLAS型CO气体检测的应用范围并且保证了数据传输的安全性。     

基于ZigBee的有害气体检测系统设计

本设计采用ZigBee无线网络和STM32F103微控制器实现H2S,CO和CH4三种有害气体浓度的采集,并采用周立功公司的ZICM2410模块组建的ZigBee无线网络进行数据通信,通过上位机软件实现对气体浓度的实时监测.系统包含硬件设计、软件设计、ZigBee无线网络通信建立等.通过实验证明,本系统检测有害气体精度高,有较高的应用价值.     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.