计算一接地金属槽，其上盖对地绝缘且具有电位 ，侧壁与底壁为地电位。用有限差分法编程计算凹槽内的电位分布。-Calculation of a metal tray earthing, the upper cover on the insulation and has potential, side wall and the bottom wall to ground potential. Calculation of potential distribution in the groove wit