微探针法测量低温下生物材料导热系数研究

Study on a Tiny Probe for Determining Thermal Conductivity of Biomaterials in Low Temperature

低温下导热系数测定对生物器官的低温保存、低温外科医学及数值模拟计算至关重要。在分析微热针法测量原理和铜电阻线热源温度特性的基础上 ,提出一种适用于宽温区导热系数测量的新方法。理论和实验研究表明本方法可以方便准确地测定生物材料及其在低温下发生相变后的导热系数。在 - 5 0～ 4 0℃温区对标准样品乙二醇和氯化钙水溶液的测量表明 ,测量误差 <4 %。对探针温升引起的加热功率的变化对测量结果的影响分析说明了控制探针温升的必要性。

Determination of thermal conductivity in low temperature is very important in organ cryopersevation,cryosurgery and numerical calculation.The technique of a tiny probe,in which copper wire is used as a linear heat source and the sensor of temperature simultaneously,is developed to determine thermal conductivity of biomaterials in wide temperature range.Theoretical analysis and experimental results show that the proposed technique can be used to determine thermal conductivity of biomaterials and that after phase change in low temperature conveniently.In temperature range-50～40℃,the maximum measurement error of standard samples,aqueous glycol and CaCl 2 solutions,is less than 4%.In order to eliminate the effect of the varied power supplied,it is necessary to control the temperature rise of the probe.