| Active Brownian Particles(ABPs)have the ability to absorb,to transform,and to dissipate energy.In recent years,studies on the characteristics of active Brownian par-ticles have attracted much attention in scientific researches.The transport properties of active Brownian particles in a modified stochastic energy-depot model with different mechanisms has been researched.At first,the background and significance of this research has been introduced in our paper.Then,in the second chapter,the theoretical basis of nonlinear dynamics has been elaborated,and in the third chapter,the theory of stochastic simulation is explained theoretically.Further,in order to explore the transport character-istics of active movements,we research these with Rayleigh-Helmholtz(RH)model and Schweitzer-Ebeling-Tilch(SET)model in this paper.In the fourth chapter,the modified stochastic energy storage model which driven by random action has been detailed described.By numerical simulating and numerical analyzing,it is compared with the model which was not modified before the linear term being added.We investigate the effects of multiplicative noise K1,additive noise K2,and correlated noise A on the transport of active Brownian particles,respectively,and the results show that:(1)The transport velocity<v1>of the ABPs are always positive whether the correlation intensity A = 0.0 or not;(2)for a small value of the multiplicative noise intensity k1 the variation of<v1>with λ shows a minimum,there exists an optimal value of the correlation intensity λ at which the<v1>of the ABPs is minimized.But for a large value of k1 the<v1>monotonically decreases;(3)the transport velocity<v1>increases with the increase of the k1 or k2,i.e.,the multiplicative or additive noise can facilitate the transport of the ABPs;and(4)the effective diffusion increases with the increase ofα1,namely,the linear term in modified energy conversion model of the ABPs can enhance the diffusion of the ABPs.The fifth chapter of this paper,the transport characteristics of ABPs in the modified stochastic energy storage model with RH model and SET model has been studied,and the results show that:(1)The linear term can break the symmetry of the effective potential function of the two models;(2)when two types of noise are not correlated and there is no periodic signal,the mean first-pass time(MFPT)always decreases with the increasing of k1 and k2,and the state of ABPs transport is unstabled.It indicates that the correlated noise can enhance or weak the stability of particles;(3)when λ≠0,MFPT increases asλ increases.When λ is small,the stability of ABPs in SET model is stronger than that in RH model,and vice versa;when k1 is small and λ is large,MFPT has a maximum value,which indicated that the noises can enhance the stability with this system driven on certain conditions;(4)in the figure of the relationship between MFPT and k1,there appears the phenomenon that the noise enhances the stability(NES)in both models;(5)when considering the periodic signal,there appears the phenomenon of stochastic resonance(SR)both in the RH model and SET model,and both are single resonance;while in the figures that the SNR changes with k1 or SNR changes with k2,the SR phenomenon only occurs in the figure of SNR changes with k1 and only when λ takes a large value.That is,correlated noise can enhance and weak the system’s stochastic resonance. |
PDF Full Text Request