M500系列激光外径测量仪

<正> M500系列激光外径测量仪是日本安立电气株式会社研制成功的。该设备采用激光新技术,是非接触式测量仪,可供玻璃纤维、金属丝、塑料电线、棒材和管子等在生产过程中测量外径之用。共有50微米到150毫米十四个规格。 M500系列激光外径测量仪的特点为: 1.由于经常对激光束的扫描振幅和光通量进行监控,因此可长期稳定地进行高精度测量,而且不受周围光线的影响。 2.扫描速度为1000次/秒,对于高速移动的被测物外径,可进行多次快速测量。 3.采用音叉振动使激光束来回扫描,故可消除由被测物体运动所引起的测量误差,     

车载三维激光测量仪单臂扫描系统的设计

为适应国内市场对三维激光测量仪的需求,研制了激光扫描设备的关键部件扫描系统.该系统可以实现三维激光测量仪360°无遮挡扫描,动静平衡,运转稳定,保证设备高速旋转扫描,并获取精确的扫描数据.     

精密真空激光大坝变形测量系统中的激光漂移问题

为满足精密大坝变形测量的要求，通过数值模拟的手段，计算、分析了真空激光波带片衍射成像测量系统中激光束的漂移对系统测量造成的影响，得到若干有益的结论:采用合适的限位孔后可以消除激光束光轴侧移对测量造成的影响，激光束光轴的倾斜并不会影响像斑主极大的位置，但会影响次极大的位置，而且可能造成像斑亮度过暗而影响测量。通过对该实际系统的运行考核，证实了数值模拟结论的有效性和可靠性。     

固体介质空间电荷与松弛电流的同步测量及应用研究

为克服固体介质内空间电荷和电导分立测量导致实验数据关联性弱的缺陷,基于电声脉冲法原理设计了一套片状试样空间电荷和电导同步测量系统,以获得同片试样在不同电场下的空间电荷和电导动态响应。首先,通过空间电荷测量中电脉冲响应的仿真计算,分析了电脉冲对同步测量时电导的干扰,并采用空间电荷和电导快速分时切换测量的模式解决电脉冲干扰。然后,基于IEC/TS62758-2012空间电荷测量技术校验规范,采用有机玻璃试样对该系统进行了系统验证,以评估空间电荷测量的准确性。最后,采用该系统对低密度聚乙烯(low density polyethylene-LDPE)试样在室温下进行了不同电场时的空间电荷和电导的同步测量,并根据空间电荷时空分布信息计算出位移电流和传导电流分布。结果表明:高(50kV/mm)电场下,半导电/LDPE试样/铝测量结构中LDPE内的位移电流明显低于传导电流,且传导电流的载流子主要源于电极的表面注入,杂质在高场下的解离对传导电流影响不明显。     

基于FPGA的MEMS测量控制系统的设计

基于频闪显微干涉(stroboscopic interferometer vision system,SIVS)技术,提出了一种MEMS三维动态测量的同步控制系统.在该系统中,频闪的参数通过有USB功能的MCU从PC配置到FPGA中,然后由FPGA分别控制测量系统中的声光调制器、MEMS驱动器、微动平移台和千兆网相机.结合开发的应用软件,可以实时测量MEMS的运动.计算表明,使用该系统所能测量的MEMS的理论最高周期运动频率为1 MHz.实验证明这种方法行之有效.     

基于同步相量测量的配电网电能质量监测技术研究

良好的电能质量是确保电力系统可靠运行的关键.对电力系统进行实时准确的电能质量监测可及时发现系统存在的问题,进行故障分析并作出相应的调整,可提高供电可靠性.为此提出了基于同步相量测量的配电网电能质量监测技术,对同步相量测量算法、谐波参数和电压闪变测量算法进行了分析,仿真结果和误差分析验证了该方法测量结果的准确性和可行性.     

基于PCI总线的高精密时间间隔测量仪的研制

在很多大型物理实验和应用中,对时间间隔测量的精度要求是越来越高.本文介绍了一种基于PCI总线的高精密时间间隔测量仪的实现,该测量仪具有内部自检、通道识别及掉电保护等功能;并说明了该测量仪的多项关键技术,尤其是延时锁相环加RC延迟线的两级时间内插技术;最后给出了该测量仪的性能指标.测量结果显示,该测量仪可以达到21ps的测量精度,同时可以测量的时间范围是51us.     

基于LabVIEW软件的光衰减长度测量系统

介绍了一种基于LabVIEW软件的液体闪烁体光衰减长度测量控制系统.对整个系统的硬件设计和控制,以及软件控制流程和系统调试方法进行了阐述,且对其实际运行效果进行了分析.该系统实现了电动平移台的位置调节、LED组的开关控制、液何传感器的数据读取和电磁阀的开关控制等功能.实验的各类数据在软件界面上可以实时显示,方便实验人员...     

计量用互感器在线监测系统的研制

在分析计量准确的重要性和目前实验室离线检测存在不足的基础上,研制了按照分布式系统设计的计量用互感器在线监测系统,并介绍了PT二次负荷、压降、误差和CT二次负荷、压降在线监测的原理和硬件电路设计方案.该监测系统采用分布同步测量方案,具有三层体系框架结构,考虑了在线监测长期运行的问题,对于测量系统和供电电源进行了可靠性设计.目前该系统已经在变电站挂网运行,测量数据准确、可靠,具有实用性.     

基于CCD的XLPE电缆料杂质颗粒测量系统的研制

应用电子耦合摄像器件（CCD）一维扫描和试样的行进构成对试样的二维扫描检测方法，研制经XLPE电缆料杂质颗粒测量系统，论文分析了透镜，CCD器件对分辨率的影响，在选定扫描视场下优化了分辨率；测量系统分辨率在20mm视场下达到35um，模板实验测中率为100％，测量每公斤料的颗粒误判率为零，用于110kV交联电缆绝缘料测量，最小颗粒为120um时，测量速度可达2．6kg/h。     

Electron beam pumped argon-excimer laser using an unstableresonator

An unstable resonator was used for an e-beam pumped argon-excimer laser in the VUV-spectral region, for the first time to our knowledge. Adoption of the unstable resonator achieved successful operations of the high output energy of 28 mJ without any damage of the resonator mirrors. Beam divergence of the argon-excimer laser output was measured with a beam profiler, which was developed in our laboratory, It was found that the output beam involved a large ASE output. The maximum focused fluence at the center of the output beam was measured to be 42 mJ/cm². The coherence of the argon-excimer laser was degraded by the ASE, which was caused due to high gain condition of the argon-excimer laser     

GHZ polarization dynamics in ferroelectric thin films

Abstract

We present results from experiments which measure the local dielectric response of ferroelectric thin films driven by microwave-frequency electric fields. The repetition rate of a mode-locked Ti:Sapphire laser is used to generate a microwave drive signal that is phase-locked to an optical probe pulse and applied to the ferroelectric thin film. The induced polarization change in the ferroelectric film is measured stroboscopically via the electro-optic effect. Polarization images are acquired by scanning the laser beam across the sample in a confocal geometry. Time resolution is achieved by changing the delay between the electrical pump and the optical probe. Initial results show large local phase shifts in the ferroelectric response of closely separated regions of a Ba_0.5Sr_0.5TiO₃ thin film. This new experimental technique may help to understand the physical mechanisms of dielectric loss in these materials.     

飞行器电力巡检探讨

随着电网的日益扩大,巡线的工作量也日益加大,飞行器作为一种运载工具,可以被应用在输电线路巡检中,通过搭载各种检测设备,以实现对输电线路的日常巡视,提高线路运维效率。基于飞行器在输电线路巡检系统中的应用进行探讨,包括对于飞行器巡线系统设计思路、飞行器巡线系统组成、不同飞行器功能定位以及工程应用关键技术问题等的研究。主要的巡检方式包括可见光巡检、红外光巡检、紫外巡检和三维激光扫描巡检。巡检对象包括线路走廊、导线、塔身、金具等。巡检内容包括线路走廊异常、设备热缺陷、电晕放电等。     

固定翼无人机巡检输电线路探讨

随着电网的日益扩大,巡线的工作量也日益加大,固定翼无人机作为无人机的一种,可以被应用在输电线路巡检中,以提高巡线的效率。基于固定翼无人机平台在输电线路巡检系统中的应用进行探讨,包括对于固定翼无人机巡线系统设计思路、固定翼无人机巡线系统组成、各分系统功能以及关键技术问题等的研究。主要的巡检方式包括可见光巡检、红外光巡检、紫外巡检和三维激光扫描巡检。巡检对象包括线路走廊、导线、塔身、金具等。巡检内容包括线路走廊异常、设备热缺陷、电晕放电等。     

基于改进 SIFCM 和区域生长的三维 CT 图像缺陷体积测量

针对工件三维CT图像中孔洞和空腔缺陷体积测量问题，本文提出了一种基于改进型空间直觉模糊C均值聚类(NL-SIFCM)和三维区域生长的内部缺陷体积自动测量算法。首先对采集得到三维CT图像进行预处理；随后使用NL-SIFCM在三维CT图像上分割得到二值化缺陷图像组，同时针对三维CT图像切片间具有空间相似性改进得到快速算法；最后对二值化图像组进行三维区域生长得到缺陷体素数和空间结构，并将缺陷空间结构显示于三维可视化软件中辅助检测人员分析缺陷。实验结果表明，对用于模拟缺陷的标准球体积测量值相对误差在1.0%以内，具有较高测量精度；并通过实际工件检测验证了该算法适用性可有效满足CT检测需求。     

输电线路走廊三维可视化技术和系统设计

结合输电线路巡视需求,利用携带激光扫描仪的无人直升机进行巡线,获得输电线路走廊的海量激光扫描数据,根据激光扫描数据对电力线走廊进行三维建模,开发了输电线路走廊三维可视化系统,实现输电线路走廊三维可视化。该系统以无人直升机的高精度三维激光点为基础获取云数据源,对云数据进行分析和处理并生成相关地形模型、铁塔/输电线模型后集成开发,能够准确有效地模拟和再现输电线路走廊内的地形、地貌、地物,并可进行三维操作,同时还能够实现无人直升机飞行过程三维实时可视化。通过无人机巡线的实际数据验证了输电线路走廊三维可视化系统的可行性和有效性。     

High-Power All-Fiber-Based Narrow-Linewidth Single-Mode Fiber Laser Pulses in the C-Band and Frequency Conversion to THz Generation

Based on highly Er/Yb codoped phosphate fibers, we have implemented all-fiber-based narrow-linewidth single-mode (SM) pulsed fiber lasers in master oscillator and power amplifier configuration. Two approaches were used to achieve the narrow-linewidth pulsed fiber laser seeds: 1) an all-fiber-based active Q-switched fiber laser using an actuator and 2) a directly modulated single-frequency continuous-wave fiber laser. Both the fiber laser seed pulses from the two approaches have the transform-limited spectral linewidth. Based on a newly developed large-core SM highly Er/Yb codoped phosphate fiber, the peak power of SM pulses can be scaled to more than 50 kW with transform-limited linewidth and diffraction-limited beam quality. These high-power narrow-linewidth SM fiber laser pulses have been successfully used to generate coherent terahertz (THz) waves based on parametric processes in a nonlinear optical crystal. The peak power of this fiber-based THz source can reach 26.4 mW.     

Modal validation of a cantilever-plate bimorph actuator illustrating sensitivity to 3D characterisation

A dynamic finite element (FE) model of a small piezoelectric plate actuator with cantilever boundary conditions is validated experimentally using operating modes, as the scale of the device prevents conventional modal excitation. A general methodology is presented for assembly of 3D modal response of the plate surface from single-point laser vibrometer data, which is an economical alternative to the automated process provided by scanning vibrometers. 1D blocked force and 2D beam assumptions prove insufficient for validation due to modes both in the length and width of the device in operation. The model is validated in the audible frequency range encompassing 12 experimental operating modes. It is shown that when conducting validation using operating modes, the experimental results, simulated frequency response and FE eigenmodes must all be compared. Discrepancies between FE and experiment are identified and attributed to manufacturing imperfections above modelling errors.     

Large deflection micromechanical scanning mirrors for linear scansand pattern generation

An electrostatically driven silicon micro scanning mirror (MSM) for one-dimensional (1-D) and two-dimensional (2-D) deflection of light is presented. A special configuration of the driving electrodes allows the use of small electrode gaps without restricting the deflection of the plate geometrically. In this paper, the starting of the oscillation and the operation of the scanner is discussed. Experimental results show that scan angles of up to 60° can be achieved at a driving voltage of only 20 V. The 2-D deflection of a laser beam is obtained by a gimbal mounting of the mirror plate. For the fabrication of the devices, SOI-wafers are used as the base material. The mechanical structures are defined by a deep silicon etch. For the electrical isolation of areas on the movable frame, polysilicon-filled trenches are used. The mechanical stability of the scanners is tested. The devices resist shocks of more than 1000 g and show no change of the resonance frequency even after long run tests of 7×10⁹ periods     

3D IMAGING OF INVERTED DOMAIN STRUCTURES BY CONFOCAL SHG INTERFERENCE MICROSCOPE

ABSTRACT

A novel nonlinear optical interference microscope which enables us to take 3D images of ferroelectric domain structures is developed. This microscope is of a transmission type equipped with the confocal optical system, and exploits, as a probe, second harmonic waves generated in a sample by an incident laser beam. We apply the microscope to the observation of periodically poled domain structure in a LiTaO₃ quasi-phase matching device.