中文说明：二维FDTD程序，采用PML边界s 用pml和mur分别计算j=1处的Hz(i，1).计算空间扩大到400*400，不加边界，运行相同的时间步
English Description：
The two-dimensional FDTD program uses PML boundary s to calculate the Hz (I, 1) at J = 1 with PML and Mur respectively. The calculation space is expanded to 400 * 400 without boundary and runs the same time step