Soliton solutions of the improved quark mass density-dependent model at finite temperature

The improved quark mass density-dependent model (IQMDD) based on soliton bag model is studied at finite temperature. Appling the finite temperature field theory, the effective potentials of the IQMDD model and the bag constant $B(T)$ have been calculated at different temperatures. It is shown that there are two critical temperatures $T_{C1}\simeq 110 \mathrm{MeV}$ and $T_{C2}\simeq 150 \mathrm{MeV}$. We also calculate the soliton solutions of the IQMDD model at finite tmperature. It turns out that when $TT_{C1}$ the bag constant $B(T)=0$ and the soliton solution becomes very weak. When the temperature approaches the critical temperature $T_{C2}\simeq 150 \mathrm{MeV}$, the solitons disappear, the confinement of quarks are removed completely