六阶状态空间模型，同步发电机模型和网络负载模型，可用于发电机励磁系统控制仿真-Sixth-order state space model, synchronous generator model and network load model can be used to control simulation of generator excitation system

2维声波方程，时间2阶精度，空间六阶精度，恒密度介质。程序里包含吸收边界和自由边界。-2-dimensional acoustic wave equation, time second-order accuracy, spatial sixth-order accuracy, constant density of the medium. Program contains absorbing boundary and free boundary.