简述布尔算符（OR）的作用。

过滤介质是过程中不可缺少的重要部分，工业中常用的过滤介质很多，主要有三类：织物介质、粒状介质和多孔陶瓷介质，在选煤厂中多用多孔陶瓷介质。

过滤介质是过滤机的重要组成部分。工业上常用的过滤介质有：①（）介质，如细砂、石砾，炭等；②（）介质，如金属或非金属丝编织的网、布或无纺织类的纤维纸；③（）介质，如多孔陶、多孔塑料等。

简述以多孔硅胶作为凝胶过滤介质的优缺点。

简述直剪仪的优缺点。【三峡大学2006年研究生入学考试试题】

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。