Using the Langevin Monte Carlo method, the influence of friction on the directed motion of a Brownian particle driven by an external noise source is investigated. The results show that the existence and change of the environment friction influence the establishment and development of the steady motion of a Brownian particle derived by nonequilibrium fluctuation. The most probable correlation time, which corresponds to the maximum current, is inversely proportional to the friction coe

An analysis has been made for the motion of an overdamped Brownian particle in a periodic potential subjected to a position-dependent stochastic perturbation and a sinusoidal external force. In the presence of the stochastic potentials, it is noticed that with the increasingintensity of the stochastic potentials, the maximum of the current in general decreases, while it is shifted to the higher temperature, and moreover, the correlation length also strongly in2uences the magnitude of the current.