滤波器的-3dB截止频率指信号幅值衰减为输入幅值（）对应的频率。

机电一体化设计中，“增强机械系统”的设计思想是什么？

机电一体化总体设计是应用（）技术，从整体目标出发，综合分析产品的性能要求，实现机电一体化产品整体优化设计的过程。

OR指令的作用是: 。( )

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。