  We investigate the electronic states and the transport properties of the CoO2
plane in NaxCoO2 on the basis of the two-dimensional triangular lattice 11-band
d-p model by using the fluctuation exchange approximation, where we consider
the Coulomb interaction between the t2g electrons on a Co site. It is found
that all of the effective mass of quasiparticles, the resistivity, the
thermoelectric power and the uniform spin susceptibility increase with
increasing x for x > 0.6. This implies that the ferromagnetic fluctuations play
significant roles on determining the electronic states. These results are
qualitatively consistent with the experiments.
