在PWM控制电路中，PWM调制方式可分为异步调制和同步调制，其中载波信号和调制信号不保持同步的调制方式称为异步调制。

输出继电器（OR）通过一对（）触点将PLC的控制信号传递给负载。

在斩波器电路中，斩波器的工作周期为10，开关的截止时间为5，斩波器的占空比是（）。

在斩波器电路中，斩波器的工作周期为10，开关的导通时间为5，斩波器的占空比是（）。

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。

无刷直流电动机如何调速？当采用PWM控制时，何谓反馈斩波方式？何谓续流斩波方式？何谓PWM电压控制？何谓PWM电流控制？

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。