AM radio can be sent over larger distances, but the quality of the sound is not as good as a later kind of radio signal processing, called frequency modulation.

VOA: special.2010.12.08

So, if something cycles through five wavelengths in a single second, we would just say that the frequency of that wave is five per second.

如果一个东西在一秒,内经历了五个波长，我们就说这个波的,频率是每秒5次。

麻省理工公开课 - 化学原理课程节选

So, for example, we were talking about a threshold frequency as in a minimum frequency of light that you need in order to eject an electron from a metal surface.

举个例子来说，我们谈论的临界频率是,光从金属表面逐出一个电子,所需的最小频率。

麻省理工公开课 - 化学原理课程节选

The diet diary--the food frequency is a different kind of questionnaire.

饮食日记,食用频率,是另一种问卷调查方式

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

The World Health Organization keeps track of what countries have cases of polio and when they occur, and what the frequency of--So, this is a map from a few years ago and there are efforts that occur occasionally.

世界卫生组织一直跟踪记录,发生小儿麻痹症的国家及发病时间,以及发生的频率,那么,这是从几年前开始统计的,一个地图,这里是一些偶然产生的成就

耶鲁公开课 - 生物医学工程探索课程节选

Any frequency can't have an energy, you have to -- you don't have a continuum of frequencies that are of a certain energy, it's actually punctuated into these packets that are called photons.

任何频率不能有个能量,你必须要-对某一个能量上,你不会有连续的频率,光子实际上分立的存在。

麻省理工公开课 - 化学原理课程节选

So that's the important take-away message from this slide. If we think about these different types of lights, microwave light, if it's absorbed by a molecule, is a sufficient amount of frequency and energy to get those molecules to rotate. That, of course, generates heat, so that's how your microwaves work.

重要的信息，如果我们看看,这些不同种类的光，微波,如果被分子吸收，它的频率和能量可以,使分子转动,这当然的，会产生热量,这就是你们微波炉的工作原理。

麻省理工公开课 - 化学原理课程节选

A food frequency--by the way, you also have the issue of whether the particular twenty-four hours that a person is interviewed is representative of their diet overall, because you can imagine how much your food intake varies from day to day.

食物摄取频率,顺便说下,还有一个问题,就是在选取的24小时里,测试者,是不是对总体有代表性,因为你可以想象,每天事物的摄入量都是不同的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选