Unusual Evolution Characteristics in Black Hole Disk-Accretion

It is shown that evolution characteristics of black hole(BH)parameters in the pure disk-accretion are determined uniquely by BH spin parameter aa_(*).Some unusual evolution characteristics of the parameters of BH accretion disks,such as angular velocity,temperature and event horizon radius,are investigated in both thin and thick disk-accretion.And the corresponding turning points,a_(*)^(c),are derived.In addition,two characteristic functions describing the evolution of BH parameters are derived for thin and thick disks,respectively.