光纤传感器在混凝土结构内应力检测中的应用

由于光纤传感器体积小，集传感与传输于一体，无电磁干扰等一系列优点，在机敏复合材料中得到广泛应用。文章提出将光纤传感器埋入混凝土结构中，实时、在线监测混凝土结构内部应力状态的变化，即一种机敏建筑结构雏型。讨论了混凝土结构中埋入光纤传感器的埋入方式，受压、受弯引起的光强输出变化与混凝土结构内部状态的关系，并对埋入光纤传感器的混凝土构件三点弯曲梁、圆柱构件进行了实验研究。实验结果表明，光纤传感器的输出变化能反映混凝土构件内部应力变化情况及裂缝的发生、发展等情况     

碳纤维强化聚合物封装的FBG传感器制备与特性试验

采用碳纤维强化聚合物(CFRP)对光纤Bragg光栅(FBG)进行封装,研制出用于测量混凝土内部应变的FBG应变传感器,分析了传感器轴向应变分布与结构参数的关系.通过在等强度梁和霍普金森压杆(SHPB)上的试验,得到了FBG传感器的静态性能指标和动态响应特性,结果表明,FBG应变传感器线性度≤1%,埋入混凝土结构内的F...     

基于光纤光栅传感技术的桥梁结构内部应变监测

利用预先埋入的光纤布拉格光栅(FBGs)实现了实际大型钢筋混凝土工程结构的内部应变监测。在施工期间，将多个FBGs传感器布设到黑龙江呼兰河大桥内部，探索了在建筑施工现场对光纤传感器进行安装、埋入以及传感线路保护的解决方案，并在桥梁施工、桥梁静载实验和桥梁运营阶段监测了呼兰河大桥局部的应变响应。现场实验表明，本系统满足土木工程结构长期健康监测的要求，为建立重要工程设施的结构健康监测系统奠定了基础。     

光纤应变传感检测的非线性有限元分析和试验

对埋入混凝土的Bragg光栅或Brillouin散射的光纤应变传感器，研究了光纤与基材间的细观力学和界面状态这一影响传感精度的首要问题。提出了采用非线性有限元分析此类界面的力学状态，并进行了界面切向刚度试验，得出了非线性分析的参数；给出了光纤-混凝土复合体中的应力分布，为混凝土的光纤应变传感检测提供了参考。     

混凝土表面式光纤光栅传感器应力传递规律研究

主要研究一种混凝土表面式的光纤光栅传感器的工作特性,应用光纤光栅的传感特性实现了对钢筋混凝土试件内部应变的测量,试件不仅就应用光纤光栅进行混凝土结构内部应变测量的技术、工艺进行研究,还对光纤光栅传感器进行了重复性实验,验证了其具有良好的一致性.同时,还考察了光纤光栅传感器的温度补偿问题,试验结果表明该方法具有较高的实用性.     

采用掩模板制作的光纤布喇格光栅传感器

光纤布喇格光栅(FBG)是国际上光纤传感技术研究的前沿热点。在恶劣环境下对复杂结构进行变形和健康监测，具有波长编码等明显的其他传感器所没有的特点。将由光纤光栅组成的阵列埋入结构材料内部，可用来监测桥梁、大坝、重要建筑物以及船体、航天器内部的温度、应变、压力及材料结构状态的变化。该文介绍了采用掩模板制作光纤光栅传感器的原理和方法，分析了采用相位掩模法制作的分布式光纤布喇格光栅传感器的灵敏度等测量性能和噪声的随机过程特性，从而为其在船舶结构变形测量技术中的应用提供了科学依据。     

钢片封装光纤光栅监测混凝土应变试验研究

研究了光纤光栅粘贴、封装与布设工艺。提出并实现一种工字型钢片封装工艺。利用金属丝固定法将封装的光纤光栅应变传感器成功地埋入到钢筋混凝土试验梁中，监测了受压区混凝土应变历程。结果显示，经修正的监测结果在小应变范围内与电阻应变片测量压应变结果一致。     

智能结构中光纤智能夹层系统的研究

根据光纤自诊断系统模块化、集成化要求，提出并研制了光纤智能夹层。这种智能夹层易于制作，且制作过程中光纤传感器完好率达100％，智能夹层的埋入对复合材料拉伸强度影响较小。在此基础上，对光纤智能夹层试件进行了轴向拉伸试验。试验表明，在一定应变范围内，单膜交错光纤中光强-应变之间具有良好的线性关系，可以在埋入复合材料之前进行标定。利用智能夹层内的光纤传感器网络和先进的信息处理技术，可以建立结构损伤主动、在线和实时监测系统。     

曲率光纤传感器的智能夹层系统研究

根据光纤自诊断系统模块化、集成化要求,将曲率光纤传感器以环形布置在PE膜的对称两面,研制了一种智能夹层系统,它可以同时测量结构的曲率和扭转。提出了智能夹层系统的标定方法。对埋有光纤智能夹层的玻璃纤维增强树脂基复合材料试件在CMT6305型电子万能试验机上进行了轴向拉伸、压缩试验和三点式弯曲性能试验,结果表明,智能夹层的埋入对智能结构力学性能有一定的影响,但影响不大。将光纤智能夹层埋入复合材料内部进行了结构曲率测试,在埋入过程中,光纤传感器的完好率达100%。与埋入前的标定结果相比,智能夹层在埋入后的曲率测量最大偏差为5.2%,说明光纤智能夹层可以在埋入复合材料之前进行标定。     

光纤F-P传感器在用于复合材料检测的实验研究

光纤法珀(F-P)传感器广泛的应用于温度、应变、振动和压力等物理量的测量,由于其体积小、精度高等独特的优点非常适合于埋入复合材料或贴在表面对其进行测量,从而实现对符合材料的损伤诊断．利用光纤F-P传感器对复合材料结构损伤进行了试验研究,并结合有限元软件(ANSYS)对光纤F-P传感器在复合材料中的埋入方式、注意事项以及分布原则等进行了综合分析,初步给出了埋入的原则．     

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.