短語詞組短語well earth electric potential 井地電位earth surface potential 電勢earth gravitational potential model 地球重力場模型induced earth surface potential 地面感應電勢earth h potential 地電位earth h potential difference 對地電位差pipeline -earth electrical potential 管地電位earth potential difference 對地電位差;對地的電位差natural earth potential 自然地電勢 返回 earth potential