Measurement of a Three-dimensional Gas Temperature Fidld with Holographic Interferometry

It is well known that optical tomography can accurately and quantitatively re-construct the refractive index field of a transparent medium and display the three dimensional image of other thysical quantities relevant to temperature or density.In this paper.a new multidirectional holographic interferometric system is built,and two kinds of image tecon-struction algoritma are introduced and an automatic image processing system of interfero-gram is designed.A three dimentsional asymmetric gad flow field above a combustor is experi-mentally investigated with holographic interferormetry.The reconstructed temperatures are similar to those measured with a thermocouple.     

Reconstruction of 3—D Temperature Field in Holographic Interferometry

The tomography technique is commonly used for the reconstruction of holographic interferometry.However, the current reconstruction method doesnˊt consider the measurement errors which are non-avoidable in the measurement and will degrade the reconstruction quality.The factors affecting the reconstruction quality are analyzed and the distribution law of the reconstruction error with experimental errors is discussed.Finally, a method to improve the reconstruction quality-the Kalman filter method is presented.     

Measuring the Object Deformation by Real Time Holographic Interferometry with Automatically Calculating Hologram

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Measuring the Object Deformation by Real Time Holographic Interferometry with Automatically Calculating Hologram^①

Used Ar^ laser as a light source,BSO(Bi12SiO20)crystal as a hologram recording material,CCD camera as a detector,and a holographic setup controlled by a computer,we have realized real time holographic interferometry in terms of 3-interferogram method.The deformation of a plate is measured under a pressure.     

Three Measurement Methods of Two-photon Absorption Cross-section

Through the experimental design and theoretical analysis, three technologies used for characterizing the two-photon absorption（TPA） properties, such as nonlinear transmission experiment and theory, Z-scan technology and two-photon induced fluorescence method, are introduced. The properties of the three experiments to be utilizable and realizable under desirable limitation are simply analyzed. The advantages of the measurements for TPA characterization are also analyzed.     

Measuring Vibration of Body with Speckle Interferometry

Speckle interferometry is an efficient method to analyze a vibration.In cetrain conditions,this technique has some outsanding advantage,and need not strict shock-proof condition,compared with the holographic method for measuring vibration,Therefors,it is suitable to anayyze a vibration with a logar amplitude.Real-time interferometry is a rapid and simple method for measuring vibration of a body,gives speckle pattern containing amplitude distribution of body-surface.By means of time-averaged method.the speckle patternis recorded in Fourier transform plane.or vibra-tion lines are seen directly with eyes,so as to analyze efficiently ampitude.phase,and mod-el of a vibration.This paper deduces the intensity distribution function with real-time method,and gives expermental demonstration of vibration body-the vibration lines with different frequencies.     

Investigation of Concrete Distortion with Real-time Holographic Method

In order to find the relationships between the distortion rule of the concrete and its surrounding stress field, a real-time optical holographic setup is used to record the distribution and the variation of the samples, the waveforms of ultrasonic emission stimulated by the micro-cracks are recorded by a transient automatic waveform recorder to determine the time, location and intensity of the actions of micro-cracks. The experiment results are worthy studying. This method provides a useful experimental approach to study the brittleness materials.     

Novel Optical Fiber Gas Sensor for On-line Measurement of Methane

Based on analysis of near infrared spectral absorption of methane,absorption type optical fiber methane gas sensor with high sensitivity using DFB LD as a source is demonstrated. Light source modulation harmonic measurement is presented in this paper. In order to eliminate the noise, the ratio of the fundamental and second-harmonic signals is used. The mathematical model of gas concentration harmonic measurement is built up.The detection result of methane concentration is also shown. Experiments have proved a sensitivity of 28×10~(-6).     

Low Temperature Characteristics of FBG Temperature Sensors with Small-size Packaging

Two small-size package methods, thin stainless steel tube based package method and plating gold based package method for fiber Bragg grating（FBG） temperature sensors, are designed. The characteristics of the FBG temperature sensors in the environment temperature between 203 K and 243 K are investigated. The wavelengths of the FBG temperature sensors as a function of the temperature are examined experimentally. The experiment results of the two different small-size package sensors in identical conditions are compared with each other. The transmission spectrum of the sensors is analyzed at the temperature of 273 K and 213 K. The temperature sensitive factors of the sensors are derived analytically and are verified by experiments. Linear fitting to the wavelength-temperature curve is carried out.     

Investigation of Concrete Distortion with Real—tim Holographic Medhod

In order to find the relationships between the distortion rule of the concrete and its surrounding stress field,a real-time optical holographic setup is used to record the distribution and the variation of the samples,the waveforms of ultrasonic emission stimulated by the micro-cracks are recorded by a transient automaic waveform recorder th determine the time,location and intensity of the actions of micro-cracks,The experiment results are worthy studying.This method provides a useful experimental approach to study the brittleness materials.     

New Optical Triangulation and Digital Image Processing in Measurement

In this paper,a new direct optical triangulation(DOT)for measuring the out-of plane displacement is given.In order to state its principle,DOT is used to mea-sure a micro-displacement of a rigid boty,and at the same time,the method of digital image processing is also given.     

激光全息双曝光法测量人体新鲜股骨皮质骨轴向泊松比

报告应用激光全息双曝光法测量人体新鲜股骨皮质骨沿长轴方向的泊松比。实验结果说明,激光全息干涉测量人体新鲜骨骼的泊松比能避免新鲜骨骼内含水份和油脂的影响。     

半导体器件工艺中热电偶可靠性测温

本文介绍了半导体器件工艺中利用热电偶测温的原理、性能以及如何对热电偶误差进行修正补偿。     

激光全息干涉在三维温度场可视化中的应用

介绍了实时激光全息干涉技术应用于三维温度场可视化的原理、实验装置与光路系统、实验结果等。通过实验成功地实现了3 种条件下三维温度场的可视化,定性地获得了溶液加热后内部温度的变化规律,并观测到溶液受热的初始阶段存在随时间迁移的“蘑菇”形干涉条纹。     

分布式光纤测温在通信机房热效能分析中的应用

随着5G技术的快速发展,通信机房快速新建及扩容,机房内设备的数量与功率骤增,传统电子测温方式存在测温点数有限、敷设传输电缆复杂、不利于维护管理等缺点,针对此类通信设备温度监测难题,提出基于拉曼散射与时域反射相结合的分布式光纤测温方法,有效提高系统测温空间分辨与降低系统敷设难度,可为机房效能分析与动态仿真平台提供高质量温度数据,并通过实验应用,验证了系统可行性,为后续通信机房高能效建设规划提供了设计参考。     

New Measuring Temperature Setup with Optical Probe^①

A new setup of measuring temperature is developed,which the probe is a micro-power consumptive one with CMOS circuit and is driven by optical power.For transmitting the measured signal and optical signal in a long distance,the fiber technology is applied in this setup.     

红外测温仪的工作原理及应用

从黑体辐射原理出发分析了红外测温的工作原理,从发射率、距离系数、环境等几个方面,探讨和分析了测温误差的原因,介绍了红外测温的应用领域以及使用过程中应注意的问题和一些使用经验.     

激光横向剪切干涉应用于温度场的测量

根据大空间自然对流水平圆管上部上升的羽状烟柱区不符合边界层假设而导致各种解之间差异的问题,提出了利用横向大剪切量干涉实验装置来实现温度场的光学测量,得到了自然对流水平圆管在不同壁温时的实时条纹。利用彩色条纹图像中RGB原始数据中的R分量的峰、谷极值点的坐标来识别明、暗条纹并得到了全场的级数分布,以此反演出全场温度分布。实验结果表明:当圆管直径d为15.6mm、剪切量s为24.2mm时,实验得到的干涉条纹类似于利用全息干涉或马赫-曾得干涉原理得到的无限宽简单条纹;干涉条纹分辨率达到75.64pix/mm;利用横向大剪切量干涉法能够准确快速地反演全场温度分布,为工程热物理分析提供相关数据。