  According to Wick's theorem, the second order self-energy corrections of
hadrons in the hot and dense nuclear matter are calculated. Furthermore, the
Feynman rules are summarized, and an effective formulation on quantum
hadrodynamics at finite temperatures and densities is evaluated. As the strong
couplings between nucleons are considered, the self-consistency of this method
is discussed in the framework of relativistic mean-field approximation. Debye
screening masses of the scalar and vector mesons in the hot and dense nuclear
matter are calculated with this method in the relativistic mean-field
approximation. The results are different from those of thermofield dynamics and
Brown-Rho conjecture. Moreover, the effective masses of the photon and the
nucleon in the hot and dense nuclear matter are discussed.
