  Information on dissipation in the entrance channel of heavy-ion collisions is
extracted by macroscopic reduction procedure of Time-Dependent Hartree-Fock
theory. The method gives access to a fully microscopic description of the
friction coefficient associated with transfer of energy from the relative
motion towards intrinsic degrees of freedom. The reduced friction coefficient
exhibits a universal behavior, i.e. almost independent of systems investigated,
whose order of magnitude is comparable with the calculations based on linear
response theory. Similarly to nucleus-nucleus potential, especially close to
the Coulomb barrier, there are sizable dynamical effects on the magnitude and
form factor of friction coefficient.
