In electronics, undesirable low frequency currents interfering with a desired signal, and usually caused by a poorly screened alternating mains supply.
在电子学领域，一种不希望发生的低频电流，它干扰所要求的信号。通常这种现象是由于交流供电线路屏蔽不良引起的。
The students are carefully screened before being granted scholarships.
这些学生在接受奖学金以前都经过严格的审查。
The film has been screened in the cinema and on TV.
这部电影已在电影院及电视上放映.
