  We obtain sufficient conditions for conservativity of minimal quantum
dynamical semigroup by modifying and extending the method used in [Chebotarev
and Fagnola, J. Funct. Anal. 153(1998), 382-404]. Our criterion for
conservativity can be considered as a complement to Chebotarev and Fagnola's
conditions. In order to show that our conditions are useful, we apply our
results to a concrete example(a model of heavy ion collision).
