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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Interferometric Fiber-Optic Electric Current Sensor for Industrial Application

    Nikolay I. StarostinMaksim V. RyabkoYurii K. ChamorovskiiVladimir P. Gubin...
    P.314-318页
    查看更多>>摘要：The interferometric electric current fiber-optic sensor for application in industry is presented. The modified spun fiber is used for sensitive fiber coil of sensor. The sensor has accuracy of 0.5% at temperature range from -40℃ to 60℃ without necessity of additional temperature compensation. The range of measured current is 15 - 250 kA. A frequency band is 0 - 5000 Hz and a nonlinearity of a sensor output is ±0.15%.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Wave Front Correction and Measurement by Using a Liquid Crystal Spatial Light Modulator

    Jian ZhangLiying WuLimin Zou
    P.319-323页
    查看更多>>摘要：To correct wave front distortion, a phased only Liquid Crystal Spatial Light Modulator (LCSLM) is used. LCSLM can modulate the phase of the incident beam by changing the electric field applied to the transparent electrodes of a liquid crystal cell. The voltage change causes the refractive index of the liquid crystal change, so a phase shift produces. The distortion of a wave front can be measured by using a wave front interferometer. Since each pixel of SLM may be addressed and controlled independently, so proper voltage is supplied to each pixel to compensate the phase corresponding to the distortion. Before wave front correction, the LCSLM is tested and corrected by employing a Twyman-Green interferometer, which shows the relationship between the applied voltage and the phase value of each pixel. Experiment result shows that after error compensation of LCSLM, the wave front distortion correction accuracy reaches 0.06 X.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Differential Reflectometry of Fiber Bragg Gratings

    Yuri N. KulchinAnatoly M. ShalaginOleg B. VitrikSergey A. Babin...
    P.324-328页
    查看更多>>摘要：A reflectometric approach is proposed for interrogation of multiple fiber Bragg grating (FBG) sensors recorded in a single fiber optic line, based on the differential registration FBGs' response to a short probing laser pulse using conventional OTDR. A special optical layout has been developed allowing transformation of FBG's spectrally modulated signals into intensity modulated signals and at the same time eliminating the susceptibility of the system to light power fluctuations. Threshold sensitivity of the method amounted to ～50 μstrain within the measurement range of ～4000 μstrain. The maximum number of FBGs interrogated by the proposed technique is estimated at several hundred, which by far surpasses the requirements of most practical applications. Due to its simplicity, efficiency and usage of conventional OTDR equipment the proposed FBG interrogation technique can find a wide range of applications, in particular in structural health monitoring.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Alignment of Cassegrain Telescope with Epps-Shulte Focus

    Vladimir S. ObraztsovAlexander A. Ageichik
    P.329-333页
    查看更多>>摘要：The results of new alignment technique for a telescope with the Epps-Shulte focus are presented. The technique is based on application of the synthesized holographic elements and IR interferometry.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Intelligent Assessment for Pathological Gait Analysis

    Sherif El-Sayed Hussein
    P.334-338页
    查看更多>>摘要：The accurate assessment of pathological gait for individual subjects is a major problem in rehabilitation centers. Automated or semi-automated gait analysis systems are important in assisting physicians in the diagnosis of various diseases. However, these systems are not only highly sophisticated but also require superior quality cameras and complex software which capture large amount of data that often proves difficult to interpret for clinical staff trying to gain insight into the patient's condition. Automation and simplification of the analysis of gait data is therefore necessary if it is to be used more productively. This research proposes a simple and cost effective approach that utilizes artificial intelligence techniques to automate the analysis and diagnosis processes. It also offers a means to compare different treatment methods and their effectiveness during the course of treatment. Visualization software has also been developed to increase the diagnostic reliability.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Fuzzy Clustering Algorithm of Early Fire based on Process Characteristic

    Rencheng ZhangJianhua Du
    P.339-343页
    查看更多>>摘要：Traditional fire detection technologies usually measure the smoke particles or the temperature increase resulted from fire. However in the early stage of fire, few particles and low heat are generated. Current fire algorithms is based on comparing the fire variables with a given threshold value, the transient sampled values are often affected by some stochastic disturbances. Consequently current methods are hardly alarm fire fleetly and reliably and often give false or failing alarm. A new fire detecting technology was presented based on early fire process signature and fuzzy clustering algorithm. The process eigenvector is made up of CO concentration in detected environment as well as its increasing rate and acceleration. The eigenvectors are divided into two categories of real fire and non-fire, the two cluster centers are obtained by using fuzzy clustering analysis. According to threshold membership principle, the real fire sources can be distinguished from non-fire sources successfully. The result of experiments has shown that the presented technology is feasible for early fire detecting with lower rate of false and failing alarm, and give fire alarm much early than any other traditional method.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Beam Pointing Precision Control by Using a Liquid Crystal Optical Phased Array

    Liying WuJian ZhangYun Fang
    P.344-348页
    查看更多>>摘要：For laser beam steering, a pure optical-electric system without mechanical or inertial parts is used. The new device is a Liquid Crystal Optical Phased Array (LCOPA). Supplying electric field to liquid crystal cell with electrodes, the extraordinary refractive index changes, which results in phase shift that modulates the direction of incident beam. The advantages of this device are small size, less energy consuming, programmable and addressable control. A one dimensional device is designed and tested. The resolution of the steering angle is 20 μrad, the range is ±2°. The effect of flyback region and phase valley on diffraction efficiency is also discussed briefly.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Detection of Indoor Formaldehyde Concentration Using LaSrFeO_3-Doped SnO_2 Gas Sensor

    Jing WangXing Ru ChenPeng Jun YaoMin Ji...
    P.349-353页
    查看更多>>摘要：Formaldehyde gas sensors with a structure of ceramic tube were fabricated by using La_(0.8)Sr_(0.2)FeO_3-doped nanometer tin oxide. The highest response to formaldehyde appeared when the heating temperature of the La_(0.8)Sr_(0.2)FeO_3-doped SnO_2 sensor was about 370 ℃. The response of the sensors to formaldehyde was measured in a gas concentration in the range of 0 - 5 ppm. The lowest formaldehyde concentration detected by 2 wt % (weight ratio) of La_(0.8)Sr_(0.2)FeO_3-doped SnO_2 gas sensor was 0.05 ppm. The response and recover times of the sensor to 0.5 ppm formaldehyde were about 120 s and 100 s, respectively. The response of the sensor to some interferent gases was tested.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Polymer Based Micro Sensors Arrays for Ph and Glucose Monitoring

    Olga KorostynskaKhalil ArshakArousian ArshakEdric Gill...
    P.354-358页
    查看更多>>摘要：Novel method of manufacturing micro sensors arrays for biomedical applications using BioForce NanoeNabler? is reported. The operation of pH and glucose sensing elements is based on the properties of polymers, which exhibit a change in their electrical characteristics (such as resistance or capacitance) on exposure to solutions with different concentrations of pH or glucose. A sensor for glucose was successfully fabricated using the enzyme glucose oxidase immobilized within the polymer poly (o-phenylenediamine). This sensor was then successfully miniaturized utilizing immobilization for a dry process. The concentrations used for the microsensor were between 1 mM and 6 mM. Samples containing different concentrations of glucose were applied to the sensor while the system was being monitored for variances in either current or conductance. The resulting changes in the electrical characteristics of the sensor monitored in real time were found to be proportional to the different concentrations of glucose applied. Microscaled interdigitated electrodes were used for sensors array, with 48 sensors places on one chip. It is envisaged that findings of this work would form the basis for miniaturised point-of-care diagnostic system.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Fiber Bragg Grating Demodulation System Based on Equi-lntensity Cantilever Beam

    Li HongYan WeipingShen RenshengWang Benyu...
    P.359-363页
    查看更多>>摘要：Optical spectrum analyzer (OSA) can achieve the higher precision and sensitivity, but it is disadvantageous for translating optical signal into electrical signal. A fiber Bragg grating (FBG) matched filtering system based on equi-intensity cantilever beam was presented in this paper. Strain characteristics in different location of cantilever beam were described, and the strain sensitivity of matching grating demodulation based on equi-intensity cantilever beam was deduced mathematically. Strain characteristics of cantilever beam were verified, and the sensing effect of the system was tested. The Bragg wavelength shift range of the demodulating FBG placed on the cantilever beam reached 10 nm, and scanning velocity was 0.125 nm/s. The system could demodulate slow-altered sensing signal accurately and rapidly.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd