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 a_*. 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.