船载微型Ga-In共晶固定点的现场复现方法研究OA北大核心CSTPCD

Application of fixed point thermometry technology to the field calibration of shipbrone sensors is a key strategy for achieving flattening in temperature measurements and enhancing the accuracy of oceanic temperature measurements.The fixed points defined by ITS90 in the temperature from-5 ℃ to 35 ℃ is inadequate,which blocks the accuracy improvement of the marine NTC thermistors.A new miniature Ga-In eutectic fixed point was developed,and the reproducibilities of the fixed point in temperature controlled box and ambient environment were investigated.Two methods including the tangent intersection method and cubic polynomial fitting were used to obtain the values of the temperature plateaus.The results showed that the reproducibility of the miniature Ga-In eutectic fixed point is better than 1 mK.In order to obtain better performance,the miniature Ga-In eutectic fixed point should be kept in solid state at temperature below its melting point.Using the tangent intersection method,the phase transition temperature of the miniature Ga-In eutectic fixed point is determined to be 15.654 9 ℃,with an expanded uncertainty of 1.54 mK(k=2).