Fiber optics in sensing and measurement

Optical techniques for measurement-interferometry, spectrometry and polarimetry“have long been used in materials measurement and environmental evaluation. The optical fiber lends get more flexibility in the implementation of these basic concepts. Fiber-optic technology has, for over 30 years, made important contributions to the science of measurement. The paper presents a perspective on these contributions which while far from exhaustive highlights the important conceptual advances made in the early days of optical fiber technology and the breadth of application which has emerged. There are also apparent opportunities for yet more imaginative research in applying guided-wave optics to emerging and challenging measurement requirements ranging from microsystems characterization to cellular biochemistry to art restoration     

Fiber optics [geophysical strain sensor]

Discusses the use of phase-based fiber optic sensors for Earth strain measurements in order to monitor stress changes. After discussing the measurement principles the authors consider the design of the sensor and read-out system. The system has been installed at White Sands Missile Range     

Status of mine monitoring and communications

A brief summary of the history of university involvement in communications and monitoring in underground coal mines is presented, beginning with the first federal appropriation of funds in 1970 under the Coal Mine Health and Safety Act of 1969 and continuing through the first half of 1985. Insight is provided into significant trendsetting work done by these universities. The first US mine monitoring project, the first US minewide monitoring system, and the first distributed microprocessor-based mine monitor system are discussed     

基于Zigbee矿井监控系统设计

针对井下复杂的特殊环境以及对外网络的封闭性，基于Zigbee技术及Ethernet技术设计了矿井控制监控系统。通过GIS方式利用AutoCad对虚拟地图的转换，实现了对井下虚拟地图信息实时显示与连接操作。最后该系统通过网页虚拟地图方式能在PC上加以显示而且能够实现地图的连接操作，从而实现远程的监控功能。     

光纤智能测温度系统在电网上的运用

基于布里渊散射的光纤光栅传感技术,利用返回激光功率"过零点"的测量方法,设计出一个可用于电网温度监测的准分布式光纤智能测温度系统.在全长100 m的16条光纤通道上安装48个监测点,实现了对每个监测点的实时温度监测,在室温下的监测精度为±2 ℃.理论上,监测的温度范围为250 ℃.     

基于ZigBee无线传感器网络的煤矿监测系统

设计了基于ZigBee无线传感器网络的环境参数检测与人员定位为一体的煤矿井下安全监测系统.系统利用安装于矿井现场的ZigBee节点采集井下多种环境数据(瓦斯、CO、温度、湿度),采用三边定位方法基于测距的无线传感器网络实现三维空间的人员定位,并利用卡尔曼滤波算法修正量测过程中的随机误差,以提高定位精度.检测信息通过工业以太网传送至地面监控主机,主机分析软件实现数据的存储、并为监控人员提供实时的矿井环境信息和人员位置信息.现场测试结果表明本系统运行稳定、功耗低、定位精度高、信息传输可靠.     

光纤分布式接触网供电设备智能监控系统

通过对接触网供电设备监控技术更新换代原由及技术要点的介绍,阐明了光纤分布式接触网供电设备智能监控系统的先进性.物理建模过程以图表形式直观表述了此系统的构成及特点.该系统在牵引供电网络中具有广泛的应用前景.     

基于LabVIEW的大气气溶胶实时监测系统设计

近年来随着人们对大气环境质量的重视程度日益提高,大气气溶胶浓度的定量分析方法也越来越受到关注。该大气气溶胶实时监测系统基于Mie弹性散射分析技术,利用LabVIEW数据流图形化编程方法完成数据实时处理、动态显示以及历史数据保存等功能。系统可以通过实时获取单个气溶胶粒子在激光照射下后向散射光的强度来分析采集样本中各粒度气溶胶粒子浓度,并以此来评估当前环境的气溶胶质量状况。此系统具有操作简单、界面友好、数据翔实的优点,可广泛应用于大气气溶胶分析领域。     

Spatial nonlinear optics for securing information

The high degrees of freedom of light, various optical structures and optical materials can be explored and applied to develop optical encryption for securing in...     

矿山物联网双CAN通信电源监控系统研究

采用STM32作为系统的主控制芯片,通过STM32的双CAN通信电源接口实现长距离通信,同时设计子系统实现逻辑控制和数据以太网通信传输。采用以太网通信将CAN总线检测的核心数据传送到远端控制室进行综合监控,通过仿真和实际案例进行测试,实现了10 km用于矿山物联网的双CAN通信系统的数据检测、远程控制和信息通讯功能,达到节能目的。     

矿用电缆绝缘监测PD信号降噪新方法的研究

在矿用高压电缆的绝缘在线监测系统中,提取的局部放电（PD）信号很容易被各种噪声和干扰所覆盖,对监测系统的准确性带来很大的影响。本文提出了一种基于特征向量算法（EVA）的改进盲均衡（BE）和自动形态学阀值（AMT）相融合的降噪方法。首先通过盲均衡自动选择一个平衡信号揭示PD脉冲,然后AMT根据均衡信号确定阀值,从而达到降噪的目的。通过实验室与现场实际测试,结果表明,通过使用所提出的方法,可以在受严重噪音污染的信号中有效地提取PD脉冲,并尽可能地保存了信号的完整性。     

一种基于WSN的矿井人员生命体征监测终端的研究

提出了一种基于无线传感网络WSN的矿工人员生命体征监测终端,该终端基于嵌入式核心处理器ARM7和嵌入式μClinux操作系统平台开发,通过WSN无线网络将采集到的矿工人员体征参数数据发送到监护中心计算机,可以实时查看矿井人员的生命体征参数信息。实验测试表明,该终端运行稳定可靠,为保障矿工人员的生命安全和事故救援提供了重要支持。     

Segmented silicon-micromachined microelectromechanical deformablemirrors for adaptive optics

Deformable mirrors improve optical efficiency of a system by correcting the wave front aberration caused by imperfections in the system components or by turbulent atmosphere in case of telescope optics. Micromachined mirror technology has the potential to substantially reduce the cost of adaptive optics systems. First, a brief review of the work in this field is presented with the goal of informing the reader of the challenges in the micromachined adaptive optics and the implementation tradeoffs including stress-induced curvature of multilayer mirrors. Then, recent results on the silicon micromachined, hybrid integrated microelectromechanical deformable mirrors for adaptive optics developed at the University of Colorado are presented. Various microfabrication processes including surface micromachining, bulk micromachining, and flip-chip assembly are implemented to fabricate high optical fill factor and large-stroke piston-type micromirror arrays. The achieved micromirror deflection for some designs is in the range of 2 to 3.5 μm, which results in the operating wavelength within infrared spectrum. Techniques to integrate microlenses on top of the micromirrors using self-aligned solder or transfer of ultrasmooth mirror plates on top of the micromirror actuators using flip-chip create high optical fill factor devices. Experimental results of aberration correction with such devices are presented     

Surface micromachined segmented mirrors for adaptive optics

This paper presents recent results for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages (less than 30 V), thus eliminating high-voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high-order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203-μm 12×12 square grid (with 16 inactive elements, four in each corner of the array). The overall array size is 2.4 mm square. The arrays were fabricated in a commercially available surface micromachining process. The cost per mirror array in this prototyping process is less than $200. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror that requires no digital to analog converters, further reducing the cost of adaptive optics systems     

煤矿6kV动力电缆绝缘在线监测系统研究

针对煤矿井下6 k V供电系统电缆离线检测的不足,设计了一种电力电缆在线监测系统,并进行了实验验证。在供电系统中注入低频电压作为系统的激励信号,运用设计的监测单元对分支电缆的低频电压和低频电流信号进行调理和精确测量,采用高性能信号处理器结合矢量方程和全波傅里叶算法,计算出所有电缆分支的对地绝缘电阻值。同时运用CAN总线建立监控系统实现了电缆线路的故障选线。实验结果表明,监测系统有效的解决了线路电抗和互感器电抗参数以及不平衡电流对测量精度的影响,可以实时监测所有电缆分支的对地绝缘电阻值,测量误差在3%以内。     

定向扩散路由协议在矿压监测系统中应用研究

针对煤矿中无线传感器网络监测系统应用需求,提出了1种基于改进定向扩散路由协议的无线传感器网络,设计并实现了1种TinyOS平台下的无线矿压监测系统.在系统中将无线传感网和骨干网相结合,利用传感节点实时的采集矿压信息,将采集到的数据定时上传到上位机,由上位机处理软件来进行分析和采取相应动作.实验仿真结果表明改进后的定向扩...     

Development of piezoelectric actuators for active X-ray optics

Piezoelectric actuators are widely utilised in adaptive optics to enable mirrors having an actively controlled reflective surface for the purpose of the wavefront correction by reducing the effects of rapidly changing optical distortion. Two new prototype adaptive X-ray optical systems are under development with the aim of approaching the fundamental diffraction limit. One proposed technology is microstructured optical arrays (MOAs) involving two or four piezoelectric strips bonded to a silicon wafer to produce a micro-focused X-ray source for biological applications, and which uses grazing incidence reflection through consecutive aligned arrays of channels obtained using deep silicon etching. Another technology is large scale optics which uses a thin shell mirror bonded with 20?C40 piezoelectric actuators for the next generation of X-ray telescopes with an aim to achieve a resolution greater than that currently available by Chandra (0.5"). PZT-based piezoelectric actuators are being developed in this programme according to the design and implementation of the proposed mirror and array structures. Viscous plastic processing is chosen for the preparation of the materials system, which is subsequently formed and shaped into the suitable configurations. Precise controls on the thickness, surface finish and the curvature are the key factors to delivering satisfactory actuators. Unimorph type piezoelectric actuators have been proposed for the applications and results are presented regarding the fabrication and characterisation of such piezo-actuators, as well as the related design concepts and comparison to modelling work.     

Planar liquid crystal polarization optics for near-eye displays

As a promising candidate for next-generation mobile platforms, virtual reality and augmented reality have the potential to revolutionize the way we perceive and...     

光纤光栅测温系统在变压器绕组热点温度在线监测中的应用

简要介绍了变压器绕组热点温度在线监测的重要性,对目前测量变压器绕组热点温度的几种测量方法进行了分析和比较,在此基础上提出将光纤光栅温度传感器粘贴在绕组表面进行测温的方法,并得出了具体的实验数据.     

空间用TiOx光学薄膜的生长机理

论述了TiOx膜的生长机理,详细研究了在电子束加热真空蒸镀膜的过程,蒸汽分压、衬底温度对膜性能的影响。讨论了通过高温高真空蒸镀的方法制备出双层增透膜TiOx/SiOy、TiOx/YOy和TiOx/AlOy,通过应用双层增透膜,太阳电池的短路电流提高36%～48%(硅太阳电池的短路电流提高近48%,砷化镓太阳电池提高近36%)。