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

他表示他测量空气的同位素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.

滚轮通常使用光学旋转编码器或磁性旋转位置传感器来测量旋转运动。

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

在功能上是等效的， 因为都测量旋转，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.

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

Scientists can measure the availability of  sunlight on Mars using Aerosol Optical Depth, or AOD, to check how much sunlight is absorbed  or reflected by pollutants in the air.

科学家使用气溶胶光学深度（AOD）来测量火星上阳光的用性，检查有多少阳光被空气的污染物吸收或反射。

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.

不会详细介绍是如何工作的，但是通过发出绿光，手表的光学 PPG 传感器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。