关系式

R²

拟合方式

$\varphi =0.0218\rho +0.8009$

0.971

线性关系

$\varphi =0.806{\text{e}}^{0.0238\rho }$

0.9757

指数关系

$\varphi =0.0771\ln \left(\rho \right)+0.8001$

0.8399

对数关系

$\varphi =0.0011{\rho }^2+0.0112\rho +0.8203$

0.9828

多项式(3项)

$\varphi =0.8044{\rho }^{0.0851}$

0.858

幂关系

$\varphi =-0.003{\rho }^4+0.0057{\rho }^3-0.372{\rho }^2+0.1048\rho +0.7486$

0.9989

多项式(5项)