  Phase structure and phase transitions in dense QCD are studied using the
Cornwall-Jackiw-Tomboulis (CJT) potential in the improved ladder approximation.
The gap function, the condensation energy and the structure of Cooper pairs are
investigated at finite temperature and density. Due to strong coupling effects
at low densities, the gap, critical temperature and their ratio deviate from
the weak coupling values. It is shown that the internal structure of Cooper
pairs are robust against the thermal effects, despite the fact that the pairs
are strongly correlated near the critical temperature. Also, the effect of the
strange quark mass, Ms on the phase diagram is examined using a simple
kinematical criterion. We discuss the behavior of the unlocking line, on which
the CFL turns into the 2SC, through the variation of Ms.
