By using telescopes in Chile, the astronomers measured Dopplershifts and thus velocities of gas in the Trifid.
利用智利的天文望远镜，天文学家测量了三裂星云中气体的多普勒频移和速度。
2
The mechanism of Doppler frequency shifts resulted from variations and movement of ionosphere is analysed, and a general model for the ionosphere involving several factors is assumed.
本文分析了电离层的变化和运动引起多普勒频移的物理机制，假定了一个包含多种因素的电离层模型。
3
The isotope shifts, hyperfine structure, spontaneous emission branch ratio of the first excited level and Doppler width of the atom vapor beam were measured using laser induced fluorescence.