New Method of Anisotropic Thermal Diffusivity and Conductivity Measurements under an Identical Experimental Setup

在低温物理和低温工程领域中，存在着许多结构各向异性的材料（如高温超导体、纤维增强塑料（FRP）），它们的电阻率、热导率等物理性能表现出各向异性的性质。提出了一种在完全一致的自发实验装置下测量二维各向异性材料各向异性热导率（Kx，ky）的新方法，并验证了该方法在200 ~ 10 K温度范围内的正确性。从薄膜电阻加热器向二维各向异性材料对角施加热流（Q），并监测几个测量点的温度。将在各点施加Q后的温度变化（△T）与通过求解具有不同各向异性热导率比（A=ky/kx）的二维扩散方程计算的温度变化（△ T '）进行比较。这一过程一直持续到△T等于△T'，并确定各向异性热导率比（A=ky/kx）。将该方法应用于YBa_2Cu_（307）高温超导体和FRPS，验证了该方法的正确性。用稳态法和非稳态法测量了接触热阻Rc。

In the field of low temperature physics and cryogenic engineerings, there are many structurally anisotropic materials (e.g ; high temperature superconductors, fiber reinforced plastics (FRPs)), in which the physical properties such as electrical resistivity and thermal conductivity show an anisotropic nature. We proposed a new technique of anisotropic thermal conductivity (Kx, ky) measurements for two-dimensional anisotropic materials under an identical and spontaneous experimental setup, and also verified the justice of this method from 200K to 10K. The heat current (Q) was diaginally applied to the two-dimensional anisotropic materials from the thin film resistance heater and the temperature at several measuring points was monitored. The change of temperature (△T) after applying Q at each point was compared with the change of the calculated one (△T') which was calculated by solving the two-dimensional diffusion equation with different anisotropic thermal conductivity ratio (A=ky/kx). This procedure was continued until △T is equal to △T' and the anisotropic thermal conductivity ratio (A=ky/kx) was decided. We applied this method to the YBa2Cu307 high temperature superconductors and FRPS and verified the justice of this method. The contact thermal resistance Rc was also measured by steady state and non steady state method.