基于BOTDA技术的电缆温度监测

由于海底电缆深埋海底,其运行状态的监测尤为重要。因此,提出基于光纤光时域反射（OTDR）的布里渊时域反射分析技术（BOTDA）的分布式光纤传感器对复合海缆进行温度监测。简单介绍了BOTDA技术的原理以及温度监测的实验。对实验测得数据进行数据拟合处理和分析。从实验的数据分析中得出基于BOTDA技术测量出电缆温度的变化趋势和实际温度变化趋势是基本吻合的。从而验证了该技术测温误差小、响应时间短、运行可靠且能实现长距离测量,可有效应用于电缆温度在线监测,为电缆导体温度的确定提供有效的参考依据。     

高压光纤复合测温电缆的研制

为利用光纤分布式温度监测系统对运行电缆的温度进行实时在线监测,自主开发了高压光纤复合测温电缆。对高压光纤复合测温电缆结构设计、光纤内置等制造过程和性能检测进行了较为详细的阐述。     

一种分布式光纤光栅电缆温度传感器

提出了一种新型分布式光纤光栅温度监测系统,可以实现电缆温度的实时在线监测。基于热传导方程和边界条件的基础上,采用有限元法对电缆温度场进行了分析,为监测电缆温度提供了理论依据。光纤光栅本身不带电,抗辐射和电磁干扰能力强,耐高压和腐蚀,非常适合用做高压电力环境中的温度传感器。通过光纤光栅的温度特性实验,在20~100℃的温度范围内,光纤光栅的中心波长随温度变化呈良好的线性,线性度达到99.8%。通过对标准的热电偶温度传感器与光纤光栅温度传感器的对比实验,表明该系统测量时间-温度变化曲线跟随性好,温度差均小于1℃,符合电力电缆温度状态在线监测的使用要求。     

用低反射率光栅阵列实现智能复合电力电缆温度监测

针对现有的电缆温度监测方法主要存在无法检测电缆内部温度和测温时易受到应力影响等缺点。针对此本文研究采用低反射率光栅(wFBG)阵列智能复合电力电缆温度监测技术,用于实时监测电缆内部及外部的温度分布情况。通过免应力光栅阵列,解决了复合电缆和光缆的过程中因光纤受力而影响光栅波长准确测量从而造成对温度的影响问题。系统通过检测wFBG波长漂移得到温度信息从而实现高灵敏度高空间分辨率的智能电缆的分布式温度在线监测。搭建了基于wFBG阵列的复合电力电缆实验系统,结果表明,该系统可以实现对电缆内部及外部温度的高精度、高空间分辨率分布式测量,电缆沿线空间分辨率达到10 cm,测温精度达到0.1℃。该低反射率光栅阵列智能复合电力电缆温度监测系统可以满足智能电网运行的实际需要。     

电缆温度及载流量在线监测系统设计与实现

文中以电缆温度在线监测系统为基础,结合有限元原理,构建电缆的有限元温度场模型,实时对电缆导体温度和载流量进行计算和分析,设计了基于分布式光纤测温的电缆温度及载流量在线监测系统,并通过对10 kV电缆的数据实测,验证该系统的实时性和准确性。该系统为评估电缆载流量,合理分配电力电缆负荷、保障电网的可靠运行提供科学依据。     

分布式光纤测温系统在电缆温度监测中应用

针对目前电力电缆安全中突出的火灾探测问题,提出了一种分布式光纤测温系统,该系统采用光时域反射技术和拉曼散射测温技术,由测温主机、测温光缆及CSM主机构成,具有极高的灵敏度和定位精度。通过光缆获得电缆表面的温度,传递到测温主机中进行数据分析,并在CSM主机上显示电缆温度状态与报警。为了证实分布式光纤测温系统的有效性,在国内某隧道对该系统进行了温度测量试验,试验结果证明,系统能准确地反应现场运行电力电缆的实际运行情况,及时发现和定位温度异常点,当电缆表面温度超过系统设置的预报警温度值时,系统会立刻输出报警信号,为电缆故障提供温度预警功能,避免电力事故发生。     

光纤布拉格光栅电气测温系统的研究和设计北大核心

为了避免电力系统中设备或者线缆发热引起火灾事故,实现对电气设备的在线温度监测已成为电力系统安全与稳定的重要保障。文章设计并实现了一种高速率、高精度和低成本的适合工程应用的分布式光纤光栅电气测温系统,对陶瓷封装的光纤光栅传感器的温度响应特性进行了实验验证,结果表明,光纤光栅传感器的反射波长与温度具有良好的线性关系。通过对电力高压开关柜的长期温度监测,证明了该系统具有良好的稳定性和较高的测温精度,适用于电力系统测温领域。     

基于DSP光纤光栅温度在线监测系统设计

介绍了一种基于DSP光纤光栅的温度在线监测系统,在分析光纤光栅温度传感原理的基础上,论述了提高该系统波长测量精度的技术要点,并给出了系统硬件和软件的设计方法。该系统解决了光纤光栅波长解调的关键技术问题,实现了对电力设备各方位温度变化的实时在线监测。系统监测范围广、精度高、运行稳定可靠,可实现远程集中的自动化管理,通过实际运行结果,证明该系统具有良好的应用前景。     

一种新型的通讯电缆防盗与监测方法

阐述一种基于温度的电力电缆接地线防盗监控装置方法,通过单模长距离光纤测温及长距离光纤振动的分析,基于单模通讯光缆的电缆沟环境温度及电缆防盗综合实时在线监测。从根本上解决及时发现、定位并预警对电力电缆的外力破坏行为,提前感知电缆沟环境温度异常及外力破坏点,能够为电力电缆的安全运行及管理部门和人员及时发现环境温度异常变化和偷盗事件,为电力电缆的安全运行提供有力的技术保障。在实际应用时,该方法对温度的感应可以控制在±2℃,通过温度的变化,测出对应的距离控制在±5m,从而实现电缆的监控,为电缆的监测提供新的方法。     

基于光纤光栅的射频同轴开关簧片温度测试研究

对基于光纤光栅测温原理的射频同轴开关内部簧片温度检测进行了研究,并使用了由聚酰亚胺涂覆的光纤光栅。温度校准后,外界温度与光纤光栅中心波长拟合直线的线性度为99.914%。温度每上升1 ℃,中心波长漂移10.39 pm。将校准后的光纤光栅置于射频开关簧片处进行测温试验。结果表明,射频开关的内部温度达到300 ℃时,光纤光栅理论上的中心波长偏移误差为0.02 nm,相应的温度重复测试误差为2 ℃。该研究为射频同轴开关内部簧片的温度检测提供了有效方法。     

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.