输出继电器（OR）通过一对（）触点将PLC的控制信号传递给负载。

同一闭环控制系统的闭环特征多项式和开环特征多项式具有（）的阶次。

什么叫开环控制系统、半闭环控制系统和闭环控制系统？

同一闭环控制系统的闭环传递函数和开环传递函数具有相同的（），单不存在（）

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。

同一闭环控制系统的开环传递函数和（）是唯一的。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。