有限差分法求解一维瞬态热传导方程，初始条件为0，边界条件为第一类边界条件和第三类边界条件。-Finite difference method for solving transient heat conduction equation in one dimension, and initial condition is 0, the boundary conditions are the first boundary condition and the third boundary condit

先求解一维瞬态热传导有限元方程前若干阶特征值和特征向量，再利用模态叠加法求解瞬时温度变化(Firstly, the eigenvalues and eigenvectors of the finite element equations of one-dimensional transient heat conduction are solved, and then the modal superposition method is used to solve the transient tem