共查询到18条相似文献,搜索用时 93 毫秒
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高纯铂丝作为标准铂电阻温度计的传感元件,其氧化与分解机理是影响温度计稳定性的关键因素。采用差示量热扫描法与X射线光电子能谱共同分析了2种类型的铂氧化物PtO2和PtO在低氧分压下的分解过程。结果表明:2种氧化物的分解温度对氧气分压有明显的依赖性,氧气分压10kPa下,570℃时PtO2基本完全分解为Pt单质和PtO;在氧分压为3kPa下PtO;2的起始分解温度约为520℃,565℃以上大量分解为Pt单质,且当温度达到585℃时,PtO2分解为Pt的速度达到最快。研究结果可为铂电阻温度计的制作工艺、计量检定规程的完善提供数据参考和理论支持。 相似文献
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给出了在0~660.323℃温区标准铂电阻温度计(SPRT)的两个二次偏差函数:一个是由水三相点、锡凝固点和铝凝固点的检定值来确定;另一个由水三相点、锌凝固点和铝凝固点来确定。这两个二次偏差函数是ITS-90温标在0~660.323℃温区标准铂电阻温度计偏差函数的一个很好的近似。使用70支标准铂电阻温度计检验了这两个偏差函数,其误差一般不超过2.4mK,最大不超过4.7mK。 相似文献
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为了研究热迟滞性对工业铂电阻温度计测量不确定度的影响,选取了8支高精度铂电阻温度计进行实验。在-50~150℃内,选择3个温度区间,采用两种标准方法(IEC 60751,ASTM E644)测量水三相点(0.01℃)和所选温度范围内的中间点的迟滞性变化。实验结果表明:4支薄膜铂电阻温度计在两种标准方法测量下,随着温度区间跨度增大,热迟滞性影响增大,IEC 60751标准方法测量的热迟滞性最大值为14.2mK,ASTM E644标准方法测量的热迟滞性最大值为20.5mK;选取4支铂丝铂电阻温度计在温度范围为-50~150℃测量时,IEC 60751和ASTM E644标准方法测量的热迟滞性数据最大值分别为1.1mK和0.9mK;铂丝铂电阻温度计热迟滞性明显小于薄膜铂电阻温度计。 相似文献
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精密铂电阻温度计是介于标准铂电阻温度计与工业铂电阻温度计之间的测温传感器,利用ITS-90国际温标定义的固定点分度精密铂电阻温度计可以提高测温准确性和稳定性,但经常会出现超出内插方程所规定的温度范围以致无法用定点法分度的问题.本文对精密铂电阻温度计利用水三相点及镓熔点进行分度,调研了通过0~29.7646℃温区内插方程直接外推到70℃的可行性.实验以两支精密铂电阻温度计为对象,对定点法外推结果与直接比较法进行比较,结果显示:外推结果与标准值最大差值为1.5mK,表明精密铂电阻温度计利用水三相点及镓熔点进行分度并外推至70℃在一定的测量水平要求下是可行的. 相似文献
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A. V. Kryukov 《Measurement Techniques》2006,49(12):1218-1223
The static characteristics of platinum resistance thermometers with different platinum purities were measured. It is shown
that in the 0–420°C range the ITS-90 method gives an error of less than 0.01°C, while in the 0–230°C range the error is less
than 0.006°C.
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Translated from Izmeritel’naya Tekhnika, No. 12, pp. 33–36, December, 2006. 相似文献
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铂丝的位错是影响标准铂电阻温度计性能稳定性的重要因素之一。从微观角度出发,借助X射线衍射(XRD)分析方法,开展了退火时间对铂丝位错密度影响的研究,并利用标准铂电阻温度计退火实验数据进行了验证。结果表明:实际用于标准铂电阻温度计直径为0.07mm的新制铂丝(纯度99.999%)平均位错密度随着退火时间呈指数减小,经过100h退火后位错密度从1012cm-2下降到1011cm-2,300h后其位错密度基本保持稳定;新制标准铂电阻温度计在退火前300h其水三相点电阻值明显减小,退火300h后水三相点值变化量小于3mK并趋于平稳,此结果从热处理时间上与铂丝位错实验结果基本吻合。研究结果为标准铂电阻温度计制作工艺的提升及计量检定规程的修订提供技术支撑 相似文献
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A procedure for reproducing the International Temperature Scale ITS-90 for solving special measurement problems is considered.Translated from Izmeritelnaya Tekhnika, No. 11, pp. 46–49, November, 2004. 相似文献
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A thermodynamic temperature scale in the range 0.3–3 K is established by a magnetic method. The results of investigations
enable the range of the State Standard of temperature to be extended from 0.8 K to 0.3 K with a simultaneous increase in its
accuracy by a factor of 2–3.
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Translated from Izmeritel’naya Tekhnika, No. 8, pp. 47–53, August, 2007. 相似文献
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Results of an investigation of small-size ampoules of the fixed points of gallium and indium are described. It is concluded that they can be used as an inexpensive standard means of measuring temperature. 相似文献
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A new comparison system has been constructed using a Gifford- McMahon type cryogenic refrigerator for the calibration of capsule-type
standard platinum resistance thermometers (CSPRTs) below 273.16 K at the National Metrology Institute of Japan (NMIJ). The
system can compare six CSPRTs at once. A gold-plated comparison block, in which CSPRTs are mounted for calibration, is made
from oxygen-free high-conductivity copper. The standard uncertainties related to the temperature control of the system are
estimated to be 0.04 mK. The calibrated values for CSPRTs and a rhodium–iron resistance thermometer obtained using the comparison
system are in good agreement with those obtained by the direct realization of the low-temperature fixed points of the ITS-90
within the combined standard uncertainty for the calibration using the comparison system. 相似文献
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Systems for realizing the fixed points of the ITS-90 for calibrating column and capsule standard platinum thermometers, namely,
the triple points of argon and mercury and the melting point of gallium, are constructed and investigated. The errors of the
values of the metrological characteristics of the systems obtained enable one, using platinum resistance thermometers, to
reproduce and transfer the temperature scale in the 83.8–302.9 K range. The extended uncertainty in reproducing the temperatures
of the fixed points does not exceed 0.4 mK.
This paper has been prepared from the contributions presented at the 3rd All-Russia Conference “Temperature 2007”; see the
selection of papers in Measurement Techniques, Nos. 8 and 9, 2007.
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Translated from Izmeritel’naya Tekhnika, No. 11, pp. 26–31, November, 2007. 相似文献