With transport characteristics and experiment about molecular motor,an impact force model is established,which conforms Langevin equation.Kinetics of molecular motor transport is analyzed.Molecular motors could take stable stepping motion and effective transport in right impact force combined with noise intensity.Direction of motion of molecular motor is adjusted by direction of impulse force.Though average speed is not zero at different noise intensity,efficient transport of molecular motor ensemble indicates that the system is selective on noise intensity.Average speed of molecular motor ensemble decreases with increasing of load force,the motion even changes its direction as load force is great enough.

We study effect of additive Lévy noise and periodic force on dynamics of spiral waves,which appears in a FitzHugh-Nagumo excitable system.Motion of spiral tip changes regularly with external force period in domains,which can be explained with corresponding Fourier spectrum.A regular change is due to the existence of frequency-locking.Lévy noise sequence contains large-scale noise with a small probability.Large-scale noise has main effect on the motion of spiral tips.We pointed out that effect of Lévy noise on tip motion depends on period of external force.At appropriate parameters,the Lévy noise leads to the disappearance of spiral waves,and it offer a methold of controling and eliminating spiral waves.The locking behavior between internal period of the system and external modulation period is analyzed.Arnold tongues is obtained at various noise intensities.They indicate existance of stochastic resonances.