Investigation On The Transport Properties Of Coupled Ratchet With Asymmetric Friction

At present,researches about biomolecular motors has generally attracted peoples’ interests.First of all,biological molecular motors are kinds of zymoprotein macromolecule that exist in cells widely and the size of molecular motors is nanoscale.Secondly,biomolecular motors can make use of intracellular free energy to complete all kinds of internal biological transports by transforming chemical energy into mechanical energy.For example,F-action motors,myosin motors and cross-linking protein can finish mechanical motion,furthermore,dynein and kinesin can carry out cargo when dragging vesica by moving step by step.The kind of directional movement of biological molecular motors plays a very important role in intracellular material transportation.Researchers investigate the character of motors by simulating biomolecular motors’ motion with Brownian particles which existed in heating bath,therefore,people put forward plenty of Brownian ratchets to investigate motors’ transports.Till now,a large number of relevant experiments show that the conversion efficiency of biomolecular motors are generally high when motors moving collectively step by step with dragging loads,but the theoretical calculating energy conversion of ratchet models are generally low,so how to improve the energy conversion of Brownian motors with dragging loads is still a significant subject.Until now,most researches of ratchet models considered damping frictional coefficient as unit.In fact,the concentration and impurity of cell sap affects the actual frictional damping conditions,the real damping friction is always changing,therefore,investigating on transport properties of frictional Brownian ratchets with external force and loads is necessary.By investigating transport properties of frictional ratchets we can not only improve energy conversion of Brownian ratchets theoretically,but also can provide theoretical reference for manufacturing informative and sensitive nanometer devices.In this paper we investigated coupled Brownian motors’ directed transports andenergy conversion efficiency with asymmetric frictional damping conditions according to random energy theory.In addition,we discussed the relevant results that how damping friction,periodic external force and coupling strength affect Brownian motors’ transport property.On the basis of the investigation,we found that under specific asymmetry of frictional damping,the transport of frictional ratchet will be enhanced,furthermore,an appropriate frictional damping coefficient ratio can reach coupled ratchets’ transport maximum,the energy conversion efficiency can obtain two maximum.In addition,under certain frictional damping condition,the external force can obtain coupled particles multimodal structure.The research also found that the transport property can be enhanced under appropriate free length and coupling strength.All results obtained in this paper can not only be used in enlightening selecting appropriate frictional damping experimentally to improve Brownian motors’ directional transport properties and offer relevant reference in investigating how frictional damping affect Brownian motors’ transport,but can also be used in ATP procession and digital delivery.