通过以闭合曲线L为边线的任意曲面的磁通量均相等( )。

极小曲面的高斯曲率K小于等于0. ( )

磁场的高斯定理为,该定理说明磁场是无源场,即磁场是涡旋场。( )

磁场的高斯定理为,即通过任意闭合曲面的磁通量必为零,该定理说明磁场是有源场,。( )

输出继电器（OR）通过一对（）触点将PLC的控制信号传递给负载。

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。