  The relationship between abundances and orbital parameters for 235 F- and
G-type intermediate- and low- mass stars in the Galaxy is analyzed. We found
that there are abundance gradients in the thin disk in both radial and vertical
directions (-0.116 dex/kpc and -0.309 dex/kpc respectively). The gradients
appear to be flatter as the Galaxy evolves. No gradient is found in the thick
disk based on 18 thick disk stars. These results indicate that the ELS model is
mainly suitable for the evolution of the thin disk, while the SZ model is more
suitable for the evolution of the thick disk. Additionally, these results
indicate that in-fall and out-flow processes play important roles in the
chemical evolution of the Galaxy.
