Doppler two-color laser anemometer

例句：

1. 1. The scientist used a Doppler radar to detect the approaching enemy.
   科学家使用多普勒雷达探测接近的敌人。
2. 2. The car's speedometer shows a slight Doppler shift due to the wind.
   汽车的转速表显示由于风速的原因出现了轻微的多普勒偏移。
3. 3. In physics, the Doppler effect is a phenomenon whereby the frequency of a wave changes when it passes through a medium witha different speed of propagation.
   在物理学中，多普勒效应是指当波通过速度不同的介质时，其频率发生变化的现象。