1. College of Metrology & Measurement Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. National Institute of Metrology, Beijing 100029, China
3. China University of Petroleum, Beijing 102249, China
Abstract：In response to the urgent need to replace standard mercury thermometers under the Minamata Convention, a high-precision interpolation method for body temperature range and a feasibility study on its replacement were carried out using a negative temperature coefficient (NTC) thermistor thermomete with high stability and significant nonlinear characteristics. The study was conducted using national primary temperature standard instruments. The results show that the domestic NTC thermistor thermometers, which are used to replace the mercury thermometer, can obtain annual stability better than 4 mK at the gallium melting point. The optimal combinations of calibration points for the Steinhart-Hart and Hoge-1 equations (3-point interpolation) are 35℃, 41℃, 45℃. The Hoge-1 equation shows better interpolation characteristics with a maximum fitting residual of 1.2mK, which shows feasibility of alternative. The results will provide technical support for the development of NTC thermistor-based standard thermometers and promote the replacement of standard mercury thermometers.
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2023, Vol. 44 
