家庭天然气管道泄漏检测系统的设计

这里设计了一种结构简单且具有较强实用意义的家庭天然气管道泄漏检测系统。该系统基于AT82S52单片机收集信号,并针对天然气的特征进行各类气敏传感器的对比选择。使用MQ-2型半导体气敏传感器,用C语言进行程序编程,最终制作出的监测系统实物可以通过按键设定报警浓度上限。当空气中天然气的浓度超过预定值时会出现声光双重报警,且制作成本较低。     

简易可燃气体泄漏报警器

该简易可燃气体泄漏报警器电路如附图所示.由气敏传感器QM-N5、单时基LM555组成的可控多谐振荡器等构成,可用于煤气、天然气、石油液化气的超浓度检测及报警.     

基于HC32L136的液体推进剂泄漏无线监测系统设计

为提高对液体推进剂泄漏的监控能力,提出一种基于多通道气敏冗余的无线式气体浓度传感器组合的液体推进剂泄漏的无线监测系统,减少传统的单通道气敏元件监测传感器因气敏故障存在漏报或误报的不足。利用国产化微控制器HC32L136内置ADC采集2种电化学传感器（偏二甲肼和四氧化二氮）共6路气体浓度数据进行表决运算;RTC周期性唤醒微控制器,透过UART接口由2.4 GHz无线模块将采集的数据传输至手持终端或现场监测报警主机并报警显示,再按相关标准进行标准气测试及环境适应性试验考核。测试结果表明：推进剂泄漏无线监测系统周期性监测2种推进剂气体浓度、电池电量等参数,误差结果在±3%F.S.范围内,声光报警准确,误报率低。该系统具有功耗低、可靠性高、安装方便等优点,为液体推进剂泄漏监测提供一种新的技术手段。     

基于单片机的天然气报警系统设计

为了有效减少我国家庭火灾事故的发生,提高人民家庭的安全水平,给人们带来更为舒适放心的生活环境,设想如果可以研发结构简单、经济实用的家庭烟雾报警器实现天然气报警系统的智能化,那就可以大幅度地减少家庭火灾事故发生的概率。本文根据单片机原理与传感器理论,提出一种基于单片机的天然气报警系统设计,它以单片机为控制核心,通过分析气敏及温度传感器模块传递回来的数据以达到蜂鸣器报警的目的。气敏传感器及温度传感器检验天然气的易实现性、高精度性以及自适应理论的应用,都使得该报警器可以更精确的检测并报警。通过理论研究与仿真演示,证明此报警器可以很好的完成检测及报警目的,但要达到实际应用还需要进一步的探讨与研究。     

基于TGS813的家用可燃气体泄漏报警装置的设计

提出基于气敏传感器TGS813的家用可燃气体泄漏报警通风装置的设计方案.该设计的系统利用TGS813对可燃性气体进行监测,当气体浓度超标时,传感器输出的电压信号将大于设定电压,比较器比较之后正向输出,经过功率放大,最后驱动音响报警电路及排气装置.该设计具有线路简单、成本低、操作方便等优点.     

基于LCD显示的空气酒精浓度监测仪的设计

空气酒精浓度监测仪是基于单片机的可编程的智能仪器.本课题采用MQ3酒精气敏传感器和单片机系统实现酒精浓度监测仪的设计,并且通过LCD液晶实时显示.并可用键盘设定阈值,并具有超值报警功能.本课题分为两部分:硬件设计部分和软件设计部分.硬件部分为利用MQ3气敏传感器测量空气中酒精浓度,并转换为电压信号经A/D转换后传给单片机系统,由单片机及其外围电路进行信号的处理,显示和浓度值的超阈值声光报警.软件部分用汇编语言进行编程,程序采用模块化设计思想.     

气敏传感器QM—N5在矿井中的应用

通过气敏传感器采集信息，555定时器转化信号来检测矿井中瓦斯的浓度，以避免更多的人员伤亡。用气敏传感器QM—N5采集矿井中信息，通过555定时器转换成数字信号，再通过温湿度补偿电路滤除一些随机干扰，最后进行显示与报警。提出了一套完整的测量矿井中瓦斯浓度的方案。该方案结构简洁可靠，能够测量矿井中瓦斯的浓度。     

碳纳米管在气敏传感器应用中的研究进展北大核心

以具有大的表面积及特殊的中空结构的碳纳米管（CNT）作为气敏传感器敏感层材料为基础,介绍了CNT在开发不同类型气敏传感器技术方面的最新进展。综述了CNT及以贵金属、金属氧化物、聚合物改性的CNT作为气敏传感器材料的研究现状,并以气敏传感器的灵敏度和响应速度为标准,对比了CNT与三种CNT复合材料作为气敏传感器敏感层的优缺点。总结了每种传感器的设计方法、制作工艺和传感机理,提出了CNT气敏传感器当前面临的技术挑战,并对以后CNT作为气敏传感器材料的发展进行展望。     

CO／H2集成FET型气敏传感器的研究

本文初步探讨了FET型气敏传感器的敏感机理,采用N阱双极MOS兼容工艺,将CO,H_2气敏单元,择优差分型气敏单元、加热单元、温敏单元单片集成,制作了可调高温的具有高稳定输出的芯片自恒温系统,研制出具有良好的选择性和稳定性,较高灵敏度的集成MOS气敏传感器.     

简易可燃气体泄漏报警器

该简易可燃气体泄漏报警器电路如附图所示。由气敏传感器QM-N5、单时基LM555组成的可控多谐振荡器等构成,可用于煤气、天然气、石油液化气的超浓度检测及报警。QM-5N是一种半导体气敏元件,F-F间为电加热丝,工作电压为5±0.5V,由三端稳压集成电路T805稳压供给,而且要求正式工作前要通电预热3分钟左右。A、B两电极为测量端,其阻值随感测到的可燃气体浓度而交化:静态时A、B间电阻值甚大,被测可燃气体浓度超过允许范围(一般取0.05%)时,A、B间电阻值骤减,B点电位上升,当LM555第④脚复位端MR电位高于1V时,其内部电路工作,开始报警。当气体浓度恢复至正常值以下时,QM-5N气敏元件要经过约10秒钟的恢复时间后,     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.