非接触式红外体温计

本文设计了一种非接触式的体温计,系统利用红外温度传感器ZTP-148SR实现对体温信号和环境温度信号的非接触检测,AT89S52控制ADC0809CCN对调理后的两路信号进行分时采集和转换,转换后的两路数字信号经过单片机处理,将最终得到的目标体温及其所处的环境温度并显示在LCD12864上。当待测体温超过设定阈值时,启动蜂鸣报警。该体温计响应速度快、性能稳定、读数方便,可以达到实时监测的目的,适合医院和家庭护理使用。     

实验室热电阻温度计标定方法研究

热电阻温度计以其众多的优点在温度测量中得到了广泛的应用,在要求的精度较高时或者应用的条件改变时就需要对热电阻进行重新标定.文章提出了一种实验室可行的热电阻温度计常温下标定方法,介绍了实验原理、所需的实验设备及实验步骤,数据分析结果表明该标定方法比较可靠.     

测温系统温度漂移的还原补偿法

本文分析了测温系统产生温度漂移的原因 ,提出了一种克服温度漂移的还原补偿方法。该方法不需要测量环境温度 ,而是采用两个标准电阻作为中间传递量 ,将测量状态下的采样值还原为标定状态下的采样值 ,从而达到温度补偿的目的。实验结果表明 ,补偿后系统测量的相对误差小于 0 2 %。     

标准光伏电池在拉萨自然阳光下的一级标定

为解决光伏电池和光伏组件在测量中的量值溯源问题,在拉萨地区采用室外直接辐照度标定方法建立了标准光伏电池一级标定试验平台,能够同时测量入射光直接辐照度、大气光谱辐照度分布、电池短路电流及温度,并提出了一级标定试验所需的实验条件及实验方法。实验表明:光伏电池一级标定试验平台性能准确可靠,可获得较为理想的标定不确定度结果。     

光伏标准电池室外一级标定的不确定度分析

利用拉萨地区较好的阳光辐射条件,采用室外直接辐照度标定方法建立了标准光伏电池一级标定试验平台,提出了一级标定试验的实验条件及方法。对一级标定试验入射光辐照度、光谱失配修正、电池短路电流及温度等参数进行了不确定度分析及评定,标定结果具有较高的参考价值。室外一级标定采用绝对辐射计溯源至世界辐射基准,测量结果准确可靠,且具有较好的复现性。     

双目摄像机标定及校正算法

双目立体视觉是计算机视觉领域的重要组成部分,其包括相机标定、立体校正、立体匹配和三维重建等相关内容。该文针对传统的相机标定方法对实验环境要求高、结果精度低以及鲁棒性差等问题,提出了一种采用张正友棋盘格标定法结合MATLAB标定工具箱的方法对相机进行标定及校正。该算法既考虑了畸变因素的影响,又对标定参数做了非线性优化,标定方法简单方便,且标定结果的准确度较高。     

支持向量机在电子体温计LED字符识别中的应用研究

在电子体温计的在线自动检测中,电子体温计发光二极管(LED)字符识别是其中的一个重要问题.提出了一种基于支持向量机(SVM)的电子体温计LED字符识别方案,通过实验选定二次多项式作为核函数,实现了对电子体温计LED字符的在线识别.在训练样本较少的情况下,该系统具有较高的识别率和识别速度,系统的识别率可达98.3%,识别速度小于0.2 S,并具有很好的分类推广能力.实践表明这种识别方法是实用可靠的.     

机场跑道摩擦系数测试车标定装置研究

根据摩擦车力传感器标定需要,提出一种机场跑道摩擦车标定方法.分析了摩擦车和标定系统的标定原理和标定方法,选用PC104模块作为控制核心,设计控制系统完成标定实验,针对标定装置中测力传感器的非线性问题,应用基于分段最小二乘法拟合的数据处理方法.实验结果验证了算法的有效性.     

一种新型的体温计校准装置

介绍了智能化体温计校准装置的研制，该装置可以广泛应用于医学临床及生化实验等领域，具有新颖性、独特性，实用性。保障体温计在销售和使用中温度量值的准确可靠性。     

光学电磁场探测探针标定技术研究

光学电磁场探测探针已逐渐开始在相控阵雷达天线测量等领域应用,它的幅度和相位测量准确度受到大家重视。为了实现对光学电磁场探测探针测量能力准确标定,本文引入电磁场测量探头的标定思路,提出利用矩形金属波导的电场产生标准幅度及相位实现对光学电磁场探测探针标定的方法,建立了标定装置,阐述标定实施过程。通过实验验证,该方法能实现对光学电磁场探测探针标定,精度满足使用要求。     

200 ℃以下红外温度计校准的相关研究

研制了一种可用于200 ℃以下的红外温度计校准的标准黑体辐射源。应用3种不同方法的计算,得到的黑体空腔的有效发射率均在0.997以上。通过一系列的试验,得出工作距离与环境温度是2个重要影响因素,给出了校准中的最佳工作距离,并指出保持温度计环境温度恒定的重要性。     

海底热流高精度测温仪的校准方法

针对海洋环境下温度参数的变化,结合海底热流测温特点,对海底测温仪测量精度的影响因素及其校准方法进行了研究。根据温盐深测量仪实验室的标定数据,对测温仪的零点漂移和温度漂移进行修正,并与海底测量仪海试原位数据进行比对校准。实际海上试验数据表明,在-2～+32℃温度范围内,海底测温仪的温度测量误差小于±0.002℃。     

Improving the Traceability of Meteorological Measurements at Automatic Weather Stations in Thailand

A joint project between the National Institute of Metrology Thailand (NIMT) and the Thai Meteorology Department (TMD) was established for improving the traceability of meteorology measurements at automatic weather stations (AWSs) in Thailand. The project aimed to improve traceability of air temperature, relative humidity and atmospheric pressure by implementing on-site calibration facilities and developing of new calibration procedures. First, new portable calibration facilities for air temperature, humidity and pressure were set up as working standard of the TMD. A portable humidity calibrator was applied as a uniform and stable source for calibration of thermo-hygrometers. A dew-point hygrometer was employed as reference hygrometer and a platinum resistance thermometer (PRT) traceable to NIMT was used as reference thermometer. The uniformity and stability in both temperature and relative humidity were characterized at NIMT. A transportable pressure calibrator was used for calibration of air pressure sensor. The estimate overall uncertainty of the calibration setup is 0.2 K for air temperature, 1.0 % for relative humidity and 0.2 hPa for atmospheric pressure, respectively. Second, on-site calibration procedures were developed and four AWSs in the central part and the northern of Thailand were chosen as pilot stations for on-site calibration using the new calibration setups and developed calibration procedures. At each station, the calibration was done at the minimum temperature, average temperature and maximum temperature of the year, for air temperature, 20 %, 55 % and 90 % for relative humidity at the average air temperature of that station and at a one-year statistics pressure range for atmospheric pressure at ambient temperature. Additional in-field uncertainty contributions such as the temperature dependence on relative humidity measurement were evaluated and included in the overall uncertainty budget. Preliminary calibration results showed that using a separate PRT probe at these AWSs would be recommended for improving the accuracy of air temperature measurement. In case of relative humidity measurement, the data logger software is needed to be upgraded for achieving higher accuracy of less than 3 %. For atmospheric pressure measurement, a higher accuracy barometer traceable to NIMT could be used to reduce the calibration uncertainty to below 0.2 hPa.     

A Vacuum Infrared Standard Radiation Thermometer at the PTB

A thermal infrared radiation thermometer was jointly developed by the Physikalisch-Technische Bundesanstalt and Raytek GmbH for temperature measurements from − 150°C to 170°C under vacuum. The radiation thermometer is a purpose-built instrument to be operated with the PTB reduced-background infrared calibration facility. The instrument is a stand-alone system with an airtight housing that allows operation inside a vacuum chamber, attached to a vacuum chamber, and in air. The radiation thermometer will serve to calibrate thermal radiation sources, i.e., blackbody radiators, by comparing their radiance temperature to that of a variable-temperature reference blackbody inside the reduced-background calibration facility. Furthermore, since it can be operated under vacuum and in air, the instrument also allows the water- and ammonia-heat-pipe reference blackbodies of the PTB low-temperature calibration facility operated in air to be compared with the variable-temperature blackbody operated under vacuum. Finally, provided that sufficient long-term stability is achieved, the instrument shall be used as a transfer radiation thermometer to carry and compare the temperature scale of PTB by means of radiation thermometry to remote-sensing calibration facilities outside PTB. The mechanical, optical, and electrical designs of the instrument are reported. Results of investigations on the temperature resolution, size-of-source effect, and the reference function are given. The heat-pipe blackbodies operating in air are compared to the variable-temperature blackbody operated under vacuum by using the vacuum radiation thermometer. References to commercial products are provided for identification purposes only and constitute neither endorsement nor representation that the item identified is the best available for the stated purpose.     

Linearizing the Self-Heated Thermistor Thermometer

A numerical method of linearizing a dc thermistor thermometer in which the power dissipated by the thermistor is sufficient to heat itself to a temperature significantly above ambient is developed and tested. It is shown that if the dissipation constant of the thermistor remains fixed, then the thermometer is able to detect temperature fluctuations considerably smaller than the internal temperature rise above ambient of the thermistor itself.     

精密铂电阻温度计的校准方法

介绍了精密铂电阻温度计的特性及0~660.323℃温度范围内精密铂电阻温度计的校准方法。提出对测量上限温度高于450℃的精密铂电阻温度计可参考使用说明书要求进行上限温度退火,进行定点法校准时,可采用熔化点温坪替代凝固点温坪,对于无法进行定点法校准的精密铂电阻温度计,可采用比较法校准及采用简化公式计算各项参数的可行性,同时指出自热效应对测量的影响。     

Triple-Fixed-Point Blackbody for the Calibration of Radiation Thermometers

A new triple-fixed-point blackbody containing the fixed-point materials aluminum (freezing point 660.323°C), zinc (FP 419.527°C), and tin (FP 231.928°C) in one device has been developed at the Ilmenau University of Technology. It enables calibration of a radiation thermometer with direct reference to the ITS-90 at three fixed points after a single adjustment of the calibration object. The setup significantly reduces the technical effort and the time for the calibration procedure. Measurements of the phase-transition temperature and the time-dependent blackbody temperature made with a transfer radiation thermometer, the Linearpyrometer LP5 of the IKE Stuttgart, are presented in the article.     

Calibration by Comparison of Platinum Resistance Thermometers Using Slow Resistance Bridges

Platinum resistance thermometers (PRTs) are calibrated at the highest level in fixed points, as specified in the International Temperature Scale of 1990 (ITS-90). However, in order to reduce cost and time, platinum resistance thermometers can also be calibrated by comparison. In the temperature range from ?100 °C to 300 °C, it is possible to achieve uncertainties as small as 5 mK. A PRT is calibrated by comparison by comparing its resistance reading with the temperature reading of a reference thermometer, placed at the same temperature inside the temperature-controlled calibration medium. The reference thermometer is commonly also a resistance thermometer, so the intrinsic measurement problem is the simultaneous measurement of two resistances. Four methods that perform this measurement are presented in this article. A special emphasis is given to the measurement with slow bridges. Slow bridges are not able to produce a stable resistance reading within 20 s after the connection of the PRT, so they are often considered to be unsuitable for calibration by comparison of PRTs. To overcome this problem, a special method that directly measures the ratio between the reference PRT and PRT under calibration is presented and analyzed. The analysis and measurement results proved that this method and consequently the slow resistance bridges are capable of performing calibration by comparison of PRTs at least at the same level as the conventional methods.     

Numerical Modeling of Heat Flux in Fixed-Point Cells Due to the Hydrostatic-Head Effect

The article presents the numerical analysis of a particular thermal effect, which occurs during the calibration of standard platinum resistance thermometers in fixed-point cells. The temperature within the fixed-point cell varies linearly with the immersion depth due to the hydrostatic-head effect, so a quasi-linear temperature gradient in the vertical direction is inherently present. If there is a temperature gradient, a resulting heat flux will appear. This heat flux flows across the thermal conductivities, which change with depth, so the resulting temperature field is distorted. The key issue that is tackled in this article is the magnitude of these temperature deviations and their influence on the measurement accuracy. This effect should not be confused with the perturbing heat exchange toward the thermal enclosure and ambient. These are independent effects that are in real systems superimposed on each other. To get a better insight into this phenomenon, a numerical model based on a finite-difference method was developed. The model allows the simulation of the measurement of the thermometer immersion profile and of the use of different bushings, as two of the methods for assessing the thermal effects. The results of the modeling showed that there is an inherent difference between the temperature measured by the thermometer sensor and the temperature at the point of the phase transition, even if the immersion depth was infinite and there was no perturbing heat exchange toward the thermal enclosure and ambient. Nevertheless, in several cases the thermometer would still almost perfectly follow the immersion-profile curve. The only exception is near the bottom of the cell, where a small deviation from the immersion profile was observed. This is in agreement with previously presented experimental results, where this behavior was noticed, but never satisfactorily explained.     

红外空芯光纤辐射温度计的研制及应用

为了对冲击发电机的轴套温度进行监测,设计并研制了一种新型的红外光纤辐射温度计.温度计主要由红外空芯玻璃光纤、红外探测器、放大电路及80C552单片机组成.在分析各部分实现功能的基础上,重点研究了环境温度变化对探测器的影响,并实现了数学建模.温度计的工作波长是8~14μm,测量温度范围是60~400℃,测试环境温度范围是25~60℃.利用可精确控温的实物标定炉和环境模拟箱对温度计进行了标定,测量误差小于2%.经过几个月的在线监测,取得了较好的测量结果.