Anti-Stokes/Stokes temperature calibration and its application in laser-heating diamond anvil cells

Anti-Stokes/Stokes Raman peak intensity ratio was used to infer sample temperatures,but the influence factors of system correction factors were not clear.Non-contact in-situ anti-Stokes/Stokes temperature calibration was carried out for up to 1500 K based on six different samples under two excitation light sources(±50 K within 1000 K,±100 K above1000 K),and the system correction factorγwas systematically investigated.The results show that the correction factorγof anti-Stokes/Stokes thermometry is affected by the wavelength of the excitation light source,Raman mode peak position,temperature measurement region and other factors.The anti-Stokes/Stokes thermometry was applied to the laser-heating diamond anvil cell(LHDAC)experiment to investigate the anharmonic effect of h BN under high temperature and high pressure.It is concluded that the strong anharmonic effect caused by phonon scattering at low pressure gradually changes into the predominance of localized molecular lattice thermal expansion at high pressure.

Design and Realization of a Portable Temperature Sensor Calibrator

Due to the complex erection environment of various types of automatic stations,the provincial meteorological inspection department is difficult to carry out this work in terms of equipment or staffing. For this reason,a portable temperature sensor calibrator was developed,and it uses semiconductor refrigeration technology to increase and decrease temperature quickly. It uses an intelligent PID temperature controller as a control device to provide a stable temperature environment; it is small,light and easy to operate,and it provides technical support for the calibration of temperature sensors. The structure and working principle of this equipment were analyzed,and its performance was tested. All the indicators could meet the requirements of field calibration. The calibrator will provide a strong guarantee for the reliability of temperature data obtained at automatic meteorological stations.

Dynamic Calibration of the Cutting Temperature Sensor of NiCr/NiSi Thin-film Thermocouple

In high-speed cutting, natural thermocouple, artificial thermocouple and infrared radiation temperature measurement are usually adopted for measuring cutting temperature, but these methods have difficulty in measuring transient temperature accurately of cutting area on account of low response speed and limited cutting condition. In this paper, NiCr/NiSi thin-film thermocouples（TFTCs） are fabricated according to temperature characteristic of cutting area in high-speed cutting by means of advanced twinned microwave electro cyclotron resonance（MW-ECR） plasma source enhanced radio frequency（RF） reaction non-balance magnetron sputtering technique, and can be used for transient cutting temperature measurement. The time constants of the TFTCs with different thermo-junction film width are measured at four kinds of sampling frequency by using Ultra-CFR short pulsed laser system that established. One-dimensional unsteady heat conduction model is constructed and the dynamic performance is analyzed theoretically. It can be seen from the analysis results that the NiCr/NiSi TFTCs are suitable for measuring transient temperature which varies quickly, the response speed of TFTCs can be obviously improved by reducing the thickness of thin-film, and the area of thermo-junction has little influence on dynamic response time. The dynamic calibration experiments are made on the constructed dynamic calibration system, and the experimental results confirm that sampling frequency should be larger than 50 kHz in dynamic measurement for stable response time, and the shortest response time is 0.042 ms. Measurement methods and devices of cutting heat and cutting temperature measurement are developed and improved by this research, which provide practical methods and instruments in monitoring cutting heat and cutting temperature for research and production in high-speed machining.

Verification and recalibration of HY-2A microwave radiometer brightness temperature

HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM)to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content,and rain rate.We verified the RM level 1B brightness temperature(T B)to retrieve environmental parameters.In the verification,TB that simulated using the ocean-atmosphere radiative transfer model(RTM)was used as a reference.The total bias and total standard deviation(SD)of the RM level 1B TB,with reference to the RTM simulation,ranged-20.6-4.38 K and 0.7-2.93 K,respectively.We found that both the total bias and the total SD depend on the frequency and polarization,although the values for ascending and descending passes are different.In addition,substantial seasonal variation of the bias was found at all channels.The verification results indicate the RM has some problems regarding calibration,e.g.,correction of antenna spillover and antenna physical emission,especially for the 18.7-GHz channel.Based on error analyses,a statistical recalibration algorithm was designed and recalibration was performed for the RM level 1B TB.Validation of the recalibrated TB indicated that the quality of the recalibrated RM level 1B TB was improved significantly.The bias of the recalibrated T B at all channels was reduced to<0.4 K,seasonal variation was almost eradicated,and SD was diminished(i.e.,the SD of the 18.7-GHz channel was reduced by more than 0.5K).

In-situ ultrasonic calibrations of pressure and temperature in a hinge-type double-stage cubic large volume press

Here,simultaneous in-situ calibration of pressures and temperatures was performed in a hinge-type second-stage cubic large volume press(LVP)up to 15 GPa and 1400 K by an acoustic travel-time approach.Based on the recently reported P-tSand P-T-tP-tSequations for Al2O3buffer rod,the cell pressures and temperatures in the chamber of LVP were insitu determined,in comparison with those by conventional off-line(or fixed-points)pressure calibration method and direct thermocouple measurement,respectively.It is found that the cell pressures of the LVP chamber are significantly reduced after annealing at simultaneous high pressures and high temperatures,owing to the stress relaxation as accumulate in the LVP chamber.This acoustic travel-time method is verified to be a good way for precise determination of thermal(cell)pressures at high temperature conditions,and is of great importance and necessity to conduct in-situ physical property measurements under extreme high P-T conditions,especially when the precious synchrotron x-ray/neutron diffraction beams are not available.

The Study of In-Orbit Calibration Accuracy of NOAA Satellite Infrared Sounder and Its Effect on Temperature Profile Retrievals

The calibration accuracy of High Resolution Infrared Radiation Sounder Mod. 2 (HIRS / 2) on NOAA-10 satellite is analyzed in this paper. The non-linear effect in the linear calibration curve induces a deviation of 1.5 degrees (k) of brightness temperature in the tenth channel (8.3 um, water vapor absorption) of the HIRS/2 and the non-linear effect affects the other channels to a different extent. Based on analyzing non- linearity in two-point calibration curve, a tri-point calibration equation is given. A numerical test of effects of the linear and non-linear calibration models on the accuracy of atmospheric temperature retrievals is carried out.

Temperature control for thermal treatment of aluminum alloy in a large-scale vertical quench furnace

The temperature control of the large-scale vertical quench furnace is very difficult due to its huge volume and complex thermal exchanges. To meet the technical requirement of the quenching process, a temperature control system which integrates temperature calibration and temperature uniformity control is developed for the thermal treatment of aluminum alloy workpieces in the large-scale vertical quench furnace. To obtain the aluminum alloy workpiece temperature, an air heat transfer model is newly established to describe the temperature gradient distribution so that the immeasurable workpiece temperature can be calibrated from the available thermocouple temperature. To satisfy the uniformity control of the furnace temperature, a second order partial differential equation(PDE) is derived to describe the thermal dynamics inside the vertical quench furnace. Based on the PDE, a decoupling matrix is constructed to solve the coupling issue and decouple the heating process into multiple independent heating subsystems. Then, using the expert control rule to find a compromise of temperature rising time and overshoot during the quenching process. The developed temperature control system has been successfully applied to a 31 m large-scale vertical quench furnace, and the industrial running results show the significant improvement of the temperature uniformity, lower overshoot and shortened processing time.

Research on sea surface temperature retrieval by the one-dimensional synthetic aperture microwave radiometer, 1D-SAMR

Due to the low spatial resolution of sea surface temperature(T_S)retrieval by real aperture microwave radiometers,in this study,an iterative retrieval method that minimizes the differences between brightness temperature(T_B)measured and modeled was used to retrieve sea surface temperature with a one-dimensional synthetic aperture microwave radiometer,temporarily named 1 D-SAMR.Regarding the configuration of the radiometer,an angular resolution of 0.43°was reached by theoretical calculation.Experiments on sea surface temperature retrieval were carried out with ideal parameters;the results show that the main factors affecting the retrieval accuracy of sea surface temperature are the accuracy of radiometer calibration and the precision of auxiliary geophysical parameters.In the case of no auxiliary parameter errors,the greatest error in retrieved sea surface temperature is obtained at low T_S scene(i.e.,0.7106 K for the incidence angle of 35°under the radiometer calibration accuracy of0.5 K).While errors on auxiliary parameters are assumed to follow a Gaussian distribution,the greatest error on retrieved sea surface temperature was 1.3305 K at an incidence angle of 65°in poorly known sea surface wind speed(W)(the error on W of 1.0 m/s)over high W scene,for the radiometer calibration accuracy of 0.5 K.

A research on high-temperature permittivity and loss tangent of low-loss dielectric by resonant-cavity technique

Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors （Q） and resonant length （L） of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.

用于定标海表测温辐射计的镓黑体辐射源

设计了镓黑体对海表测温辐射计进行定标。首先,介绍了该黑体的结构与工作原理,对黑体发射率进行仿真,并开展发射率的测量实验,讨论其不确定度的来源。然后,开展了电加热和水浴加热下镓的相变复现实验,讨论电加热功率对镓相变复现的影响。最后,通过红外海面温度自主辐射计实验对该黑体进行验证。结果表明:该黑体基于蒙特卡罗软件仿真的发射率优于0.9988,实验测得的黑体辐射源发射率结果与仿真结果较为吻合,测量重复性(标准偏差)达0.1%;相变温度坪台的复现性均优于±0.03 K;相变温坪附近时,红外海面温度自主辐射计和FLUKE 1524测温仪测得的黑体腔附近温度的数据差值均在±0.15 K以内。设计的镓黑体可以应用到海表测温辐射计进行校准,为发展自主知识产权的海表测温设备提供校准源。

连续热电偶检定炉的设计与研制

连续热电偶是基于塞贝克效应制成的一种新型温度传感器。在校准连续热电偶时,热电偶检定炉是较为重要的热源之一。该研究在传统检定炉的基础之上设计四温区检定炉,通过对炉体和温度控制的改造,对多种控温模式的设计,研制出能够适用连续热电偶等多种高温传感器校准的热源。

一种变焦红外成像测温方法

以适合大风、高温等极端天气条件下使用的固定安装式变焦测温热像仪为背景,针对连续变焦热像仪的测温问题,提出了一种变焦红外成像测温方法,在文中给出的定焦热像仪工程测温方法基础上,扩展了焦距维度,构建了变焦热像仪测温的多项式模型,并通过最优化方法计算反演参数,从而得到不同焦距时的测温结果,进一步给出了变焦测温时的数据标定方法。基于高精度黑体对自主研发的变焦热像仪进行了数据标定,分析了不同焦距时的测温精度,并进行了实验室环境和户外环境的观测试验。试验结果表明,不同焦距都可获得高精度的测温结果,达到国标要求的±2℃精度。该项成果可以在各型变焦热像仪上推广应用,提高对高压线类远距离目标的测温精度。

自动化温度阻值关系校准系统设计及优化

本文针对Pt100和热敏电阻在温度和温升测量中自动化程度低、耗时长、精度不足的问题,研究了Pt100阻值-温度关系和热敏电阻阻值变化量-温升关系,制定了一套温度校准方法,并设计搭建了温度校准系统。同时,结合校准方法与校准需求,开发了自动校准与数据处理程序。结果表明:该系统可实现全自动运行,提高了校准效率与精度,满足温度计高精度校准需求,提供了一种多类型、多温度点交叉校准的全自动控制校准方案。

恒温振荡培养箱校准方法的研究

研究建立了恒温振荡培养箱的校准方法。通过对生产厂家和用户的调研,参考相关的国家标准、行业标准和校准规范,提出一种采用多通道温度计、转速表和位移传感器作为校准装置,校准恒温振荡培养箱的温度偏差、温度波动度、温度均匀度、振荡频率误差和振荡幅度误差的方法。选择代表性的恒温振荡培养箱,依据该校准方法对计量特性进行实验验证,验证结果符合指标要求。该方法促进了恒温振荡培养箱量值溯源的标准化和规范化,推动其校准规范的制定。

深空探测超宽光谱定标黑体源研制

针对深空探测超宽光谱定标黑体源的关键技术问题,构建了一种基于优化微结构和纳米超黑涂层的深空探测星上黑体定标源。基于有限元方法仿真,验证了微锥结构不同宽高比与黑体发射率间的对应关系,确定了周期性线阵V槽结构相对于平面结构在黑体发射率方面的提升作用。优化星上黑体源高发射率微结构,优选空间超黑高发射涂层,设计星上黑体源高精度测温系统,进而完成黑体源工程设计。最后,通过星上黑体源发射率计量及实验室辐射定标稳定性测试进行验证。检测结果表明,深空探测超宽光谱定标黑体源具有超宽光谱范围、高发射率、高温度稳定性等特点,其光谱范围为5~50μm,法向平均发射率为0.986,温度稳定性达到0.16 K。该定标黑体源可大幅提升高发射率辐射定标源的光谱范围,为深空探测载荷的在轨高精度星上辐射定标提供支撑。

航空发动机叶片表面红外测温校准及温度场重构

随着我国航空业的蓬勃发展,航空发动机技术取得了长足的进步。作为航空发动机的关键组件,航空发动机叶片的研制关乎全局。对其温度进行实时、精确的测量监控有助于推动航空发动机叶片相关技术的突破。本文提出了一种基于红外测温技术的航空发动机叶片温度校准算法和温度场三维重构策略。该工作利用多层感知机网络的函数拟合能力,建立了对目标点精确温度与其周围温度分布的函数关系,并将红外测温的误差控制在1.24℃。在此基础上,采用投影法和三维点云法向量估计的创新策略,实现了二维红外图像到三维空间位置映射。该方法能从单视角红外图像得到温度场三维重构,重构过程简单,摆脱了对多视角图像的依赖。

基于距离修正的小目标中波红外光谱辐射测温方法

对高速运动的远距离空间目标而言,温度是表征其工作状态与性能的重要参数之一。准确获取目标的温度对判别其运动状态和预测其态势发展等具有重要的参考价值。目前常用的面目标或点目标的处理方法,在小目标的辐射特性测量中将不再适用,而光谱探测增加了目标在波长维度的可分辨信息,可以准确获取目标能量随波长的分布情况,为目标温度的反演提供了可能,极具应用潜力。无狭缝光谱仪可以降低对空间目标的跟踪和稳定精度的要求,具有结构简单、帧频高和响应速度快等特点,在天文观测和航天器观测等方面具有较高的应用价值。对目标红外辐射特性测量的光谱定标模型进行了分析,确定了红外探测器像元线性响应模型中的主要参数。为了减小成像距离对测温精度的影响,提出了一种基于距离修正的目标温度反演模型,提高了测温精度,符合实际工程实践应用中的精度需求,对红外辐射光谱测温具有一定的指导意义。

考虑温度影响的复合材料结构载荷测量方法

针对温度环境会影响应变法测量复合材料结构载荷精度的问题,提出了一种考虑温度影响的复合材料结构载荷测量方法。以某型飞机碳纤维复合材料平尾盒段结构剪力测量为例,首先,设计并完成了不同温度环境下的载荷校准试验;其次,采用多元线性回归法建立了常温下的复合材料结构载荷测量模型,并在不同温度条件下进行了载荷模型检验;最后,考虑温度影响对常温下的载荷模型进行了修正与验证。结果表明,文中方法具有可行性和较高的准确性。

基于导通压降的大容量IGBT模块结温观测与误差分析研究

压接式绝缘栅双极性晶体管PP-IGBT(press-pack insulated gate bipolar transistor)模块因其优越的电气性能和可靠性,广泛应用于柔性直流换流阀等大功率应用场景。IGBT芯片结温的准确观测对于其运行状态的监测与剩余寿命的评估都非常重要。已有结温观测方法多是针对键合引线式IGBT,未考虑到压接式模块的特性,无法直接应用。首先,针对大容量换流阀中的压接式IGBT,提出了一种实用的模块导通压降与结温标定方法,并对结温在线估计的误差进行了全面分析。然后,基于ABB公司5SNA 3000K452300压接式IGBT模块(4500 V,3000 A)设计了结温标定方案,包括实验电路、温度标定范围选择、结温控制方式、测量电路及标定实验步骤。最后,基于脉冲测试平台,对所提方法进行了验证。实验结果表明,所提结温标定与观测方案有效,结温观测误差在±5℃以内,且能适用压接式IGBT模块存在差异的情况。

露点传感器响应时间测试方法研究

论述了当前露点传感器响应时间特性测量在国内大型设备系统测试领域中的作用和意义,介绍了当前国内气体露点温度响应时间测量校准研究现状,设计了一种气体露点温度响应时间测试系统。该系统以测量准确度高、阶跃控制量程范围广、系统操作便捷等优势,为解决气体露点温度响应时间高精度测量的难题提供了技术支持。使用本装置分别对石英谐振露点传感器和氧化铝露点传感器的响应时间特性开展测试工作,研究结果可为未来露点传感器湿敏元件响应时间特性的研究和改进提供参考。