V·A= 4丌 V’·J(x,1)+J(x,t')V-d t=c V’.j(x,D)a J(, t) J(r, t) ds=o 4兀 s r It=C I ap(x', t)a dp(x 2 at 4 2 兀EnC at at 4丌Jrt V+c=均(vy.(x dp(x',t 2at4丌 id"=0 t=c 电荷守恒定律 A =          =  J x t dV r t c ( , ) 1 4 0         −   +    dV  r J x t J x t r ] 1 ( , ) ( , ) 1 [     机动 目录 上页 下页 返回 结束 0 1 ( , ) 4 t c J x t dV r   = =      J x t ( , ) dV r      ( , ) 0 S J x t dS r  =  =  2 2 0 1 1 1 ( , ) 4 V x t t dV c c t r t t          =       0 1 ( , ) 4 V x t dV r t       =     =     + c t A  2  1 0 1 ( , ) [ ( , ) ] 0 4 t c x t J x t dV r t    =      + =         0 电荷守恒定律