In this paper we have investigated the time evolution of a dissipative quan
tum time-dependent oscillator which can be used to model particle trapping
in an ion trap. Our analysis shows that the nonadiabatic changes in the osc
illator mass and/or frequency as well as the dissipation constitute two com
peting forces on the squeezing properties of the system - the former helps
generate the squeezing effect whereas the latter tries to destroy it.