Using rate equation theory, the equation group including the population inversiondensity of the gain medium, photon density and the absorber ground state population density is acquired.
利用速率方程理论，得到包含激光增益介质反转密度、光子密度和饱和吸收介质基态布居数密度的速率方程组。
2
The lateral inhomogeneity and the variation of density contrast with depth in the crust and their effects on the inversion of gravity field are discussed.