He says they can also measure isotopes in the air, as well as optical images pre- and post-explosion.

他表示他们还可以测量空气中的同位素以及爆炸前后的光学图像。

Scroll wheels commonly use either optical rotary  encoders or magnetic rotary position sensors in order to measure rotational motion.

滚使用光学旋转编码或磁性旋转位置传感来测量旋转运动。

They're  functionally equivalent in that they both measure rotation, but technically different, as one uses  light and optics, while the other uses magnets.

它们在功能上的， 因为它们都测量旋转，但在技术上不同， 因为一个使用光和光学，而另一个使用磁铁。

One thing to note is that in this video we covered just two methods to measure rotational motion: an  optical encoder and a magnetic position encoder.

需要注意的一点，在本视频中，我们只介绍了两种测量旋转运动的方法：光学编码和磁性位置编码。

We won't get into too much detail as to how it works, but by emitting green light, the watch's optical PPG sensor tracks blood circulation of your wrist, which outputs data to measure a little thing called your heart rate.

我们不会详细介绍它如何工作的，但过发出绿光，手表的光学 PPG 传感跟踪你手腕的血液循环，输出数据来测量一个叫做心率的数据。