  The strong interaction between heavy quarks and the quark gluon plasma makes
the open and hidden charm hadrons be sensitive probes of the deconfinement
phase transition in high energy nuclear collisions. Both the cold and hot
nuclear matter effects change with the colliding energy and significantly
influence the heavy quark and charmonium yield and their transverse momentum
distributions. The ratio of averaged quarkonium transverse momentum square and
the elliptic flow reveal the nature of the QCD medium created in heavy ion
collisions at SPS, RHIC and LHC energies.
