Sleep is divided into REM and four stages of non-REM; each has a distinct brain wave frequency.

睡眠过程可分为快速眼动阶段和四个非快速眼动阶段，每个阶段的脑波频率都不一样。

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The millimeter wave frequency with the advantages of the optic and the microwave exists between the frequency of them, and it's the perfect operation frequency of precision guidance weapon system.

毫米波的频率介于微波与红外频段之间，兼有二者的优点，是精确制导武器系统较为理想的工作频段。

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The generation of the seismic wave frequency is irrelevant to the formation thickness.

地震波频率产生和地层厚度无关。

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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

Alright. So, since we have these terms defined, we know the frequency and the wavelength, it turns out we can also think about the speed of the wave, and specifically of a light wave, and speed and is just equal to the distance that's traveled divided by the time the elapsed.

好了，我们已经定义了，这些术语，我们知道了，频率和波长，现在可以来考虑,波的速度了，特别是光波的速度，速度等于它走过的距离,除以所用的时间，因为我们。

麻省理工公开课 - 化学原理课程节选

This development is made possible by a new wave of technology: radio-frequency ID chips the size of pepper grains, broadband wireless and Web-based "dashboards" enabling monitoring and management.

FORBES: Your Product's a Hit

Using millimeter wave technology, which the TSA says emits 10, 000 times less radio frequency than a cell phone, the machine scans a traveler and a robotic image is generated that allows security personnel to detect potential threats -- and, some fear, more -- beneath a person's clothes.

CNN: Airport security bares all, or does it?