The chaotic ratchet effect for Bos-Einstein condensed atoms in an optical lattice is investigated. By using the direct perturbation method we obtain the chaotic solution of the condensed system. Theoretical analysis r...The chaotic ratchet effect for Bos-Einstein condensed atoms in an optical lattice is investigated. By using the direct perturbation method we obtain the chaotic solution of the condensed system. Theoretical analysis reveals that the transport of the condensed atoms in the ratchet potential is a chaotic one, and corresponding numerical results agree well with the theoretical results.展开更多
Using time-dependent Ginzburg-Landau formalism,we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential.In the case of collinear sliding ...Using time-dependent Ginzburg-Landau formalism,we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential.In the case of collinear sliding potential and Lorentz force,vortices are always confined in the channels induced by sliding potential.However,due to the inclination angle of sliding pinning potential with respect to the Lorentz force,vortices could be driven out of the channels,and unexpected results with multiple reversals of vortex rectifications are observed.The mechanism of multiple reversals of vortex rectifications is explored by analyzing different vortex motion scenarios with increasing ac current amplitudes.The multiple reversals of transverse and longitudinal ratchet effects can be highly controlled by ac amplitude and dynamic pinning velocity.What's more,at certain large current the ratchet effect reaches strongest within a wide range of pinning sliding velocity.展开更多
We employed molecular dynamics simulations to investigate the directed transport of a double-stranded oligonucleotide(ds DNA)through a single-walled carbon nanotube(SWNT)powered by external mechanical vibrations.It is...We employed molecular dynamics simulations to investigate the directed transport of a double-stranded oligonucleotide(ds DNA)through a single-walled carbon nanotube(SWNT)powered by external mechanical vibrations.It is thermodynamically favorable for ds DNA to adsorb inside the SWNT,and its transport through the nanotube is challenging due to the high energy barrier.However,we demonstrate that mechanical vibrations at specific frequencies can effectively drive the ds DNA through the nanotube based on a ratchet effect.The system is driven away from thermal equilibrium,and the spatial inversion symmetry is broken by mechanical vibrations.This study provides valuable insights into the mechanisms of mechanically activated DNA transport and highlights the potential of using SWNTs as nanoscale conduits for ds DNA delivery in nanobiotechnology and biomedicine.展开更多
The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was studied.The effects of mean stress and stress amplitude on cyclic deformation,ratcheting e...The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was studied.The effects of mean stress and stress amplitude on cyclic deformation,ratcheting effect and damage mechanism were discussed in detail.The results show that under symmetric stress control,the forward ratcheting deformation is observed.Under asymmetric stress control,the ratcheting strain increases rapidly with mean stress and stress amplitude increasing.Under high stress amplitude,the influence of mean stress is more significant.In addition,by studying the variation of strain energy density,it is found that the stress amplitude mainly promotes the fatigue damage,while the mean stress leads to the ratcheting damage.In addition,fractographic observation shows that the crack initiates in the brittle metal compound at the interface,and the steel has higher resistance to crack propagation.Finally,the accuracy of life prediction model considering ratcheting effect is discussed in detail,and a high-precision life prediction model directly based on mean stress and stress amplitude is proposed.展开更多
This paper proposes to use the related party transactions’(RPT)budget completion ratio(BCR)as indicator of RPT’s execution quality.This paper studies BCR by defining budget ceiling through RPTs announcement and comp...This paper proposes to use the related party transactions’(RPT)budget completion ratio(BCR)as indicator of RPT’s execution quality.This paper studies BCR by defining budget ceiling through RPTs announcement and comparing the amount disclosed in annual report as budget execution result.Through statistical analysis of 285 RPT announcements,we classify RPT’s BCR into four benchmark grades.This paper sums up the BCR of RPT from the samples,and deduces moral obligation and moral judgement curve(OJ curve)in terms of BCR.OJ curve is the real dynamic equilibrium after the struggle agency problems.From our statistical results,we verified that Weitzman’s ratchet effect exists in the budget formulation of RPTs,and it is a solid proof of Weitzman’s ratchet effect applied to real business scenarios.The empirical results show ratchet effect exists in BCR of RPTs before and after the change from GEM board listing to main board listing in Hong Kong(Transfer).This paper also finds that it is significant to find the estimated actual amount in the coming year through the budget completion ratio(BCR)of RPT from last year.This paper is a pioneer to examine the execution quality of RPT by the means of(i)Weitzman’s Truth Inducing Model,(ii)BCR,and(iii)SGR as well as(iv)estimated actual amount.展开更多
Under the theory of ratchet effect for mesoand macro-scale systems, the additional perturbation with a long time correlation and the breaking of spatial inversion symmetry are two main ingredients to bring unidirected...Under the theory of ratchet effect for mesoand macro-scale systems, the additional perturbation with a long time correlation and the breaking of spatial inversion symmetry are two main ingredients to bring unidirected transportations. With the help of a simple model system, we show that a spatially asymmetric system of the nano-scale length may induce biased transportations under thermal noise.展开更多
Time reversal asymmetry and spatial anisotropy are considered two prerequisites for Brownian ratchet.An intriguing realization can be achieved by placing an asymmetric gear in the suspension of motile rod-like bacteri...Time reversal asymmetry and spatial anisotropy are considered two prerequisites for Brownian ratchet.An intriguing realization can be achieved by placing an asymmetric gear in the suspension of motile rod-like bacteria.Usually,alignment interactions caused by anisotropic collisions or hydrodynamics would boost the ratchet effect.Here,we are concerned with a perfectly isotropic system,i.e.,symmetric gear immersed in a bath of spherical active Brownian particles.We find that,under certain conditions,kinetic symmetry-breaking arises spontaneously,i.e.,the symmetric gear keeps rotating in one direction.Unexpectedly,such ratchet phenomenon does not rely on the direct many-particle interactions and moreover the introduction of alignment interaction would counterintuitively prevent it from happening!Further investigation reveals that such spontaneous symmetry-breaking phenomenon shares similarities with the equilibrium phase transition of the Ising model.Our results provide new insights and enhance our understanding of the fundamental aspects of active ratchet phenomena.展开更多
We describe an optomechanical ratchet scheme to realize nonreciprocal transmission of a light field, which is based on the bias of the optical cavity’s frequency spectrum caused by mechanical ratchet interactions. Th...We describe an optomechanical ratchet scheme to realize nonreciprocal transmission of a light field, which is based on the bias of the optical cavity’s frequency spectrum caused by mechanical ratchet interactions. This approach to break the time-reversal symmetry of light propagation is universally valid in various optomechanical systems with ratchet-oscillator structures. We discuss specifically the implementation of an on-chip Casimir-ratchet optomechanical protocol and demonstrate the optical nonreciprocity with an extremely high isolation ratio and flexible controllability, which does not require external additional optical engineering. Our study opens a door for manipulating flexibly light propagation by using mechanical ratchet resonators, and has potential applications in the on-chip integration of nonreciprocal devices and harness of lateral Casimir forces.展开更多
基金the Key Research Foundation of the Education Bureau of Hunan Province of China under Grant No.08A015the Natural Science Foundation of Hunan Province of China under Grant No.06JJ2014 and 04JJ40006the National Natural Science Foundation of China under Grant No.10575034
文摘The chaotic ratchet effect for Bos-Einstein condensed atoms in an optical lattice is investigated. By using the direct perturbation method we obtain the chaotic solution of the condensed system. Theoretical analysis reveals that the transport of the condensed atoms in the ratchet potential is a chaotic one, and corresponding numerical results agree well with the theoretical results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11702034,11972298,and 11702218)the China Postdoctoral Science Foundation(Grant No.2019M663812)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant Nos.300102129104,3102018zy013,and 3102017jc01003)the Young Talent Fund of University Association for Science and Technology in Shaanxi,China(Grant Nos.20180503 and 20180501).
文摘Using time-dependent Ginzburg-Landau formalism,we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential.In the case of collinear sliding potential and Lorentz force,vortices are always confined in the channels induced by sliding potential.However,due to the inclination angle of sliding pinning potential with respect to the Lorentz force,vortices could be driven out of the channels,and unexpected results with multiple reversals of vortex rectifications are observed.The mechanism of multiple reversals of vortex rectifications is explored by analyzing different vortex motion scenarios with increasing ac current amplitudes.The multiple reversals of transverse and longitudinal ratchet effects can be highly controlled by ac amplitude and dynamic pinning velocity.What's more,at certain large current the ratchet effect reaches strongest within a wide range of pinning sliding velocity.
基金supported by the National Natural Science Foundation of China(Grant No.11875237)。
文摘We employed molecular dynamics simulations to investigate the directed transport of a double-stranded oligonucleotide(ds DNA)through a single-walled carbon nanotube(SWNT)powered by external mechanical vibrations.It is thermodynamically favorable for ds DNA to adsorb inside the SWNT,and its transport through the nanotube is challenging due to the high energy barrier.However,we demonstrate that mechanical vibrations at specific frequencies can effectively drive the ds DNA through the nanotube based on a ratchet effect.The system is driven away from thermal equilibrium,and the spatial inversion symmetry is broken by mechanical vibrations.This study provides valuable insights into the mechanisms of mechanically activated DNA transport and highlights the potential of using SWNTs as nanoscale conduits for ds DNA delivery in nanobiotechnology and biomedicine.
基金the financial support from the National Natural Science Foundation of China(Nos.51975271,51675260,51475223)the Starting Research Fund of Nanjing Vocational University of Industry Technology,China(No.YK20-14-05)。
文摘The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was studied.The effects of mean stress and stress amplitude on cyclic deformation,ratcheting effect and damage mechanism were discussed in detail.The results show that under symmetric stress control,the forward ratcheting deformation is observed.Under asymmetric stress control,the ratcheting strain increases rapidly with mean stress and stress amplitude increasing.Under high stress amplitude,the influence of mean stress is more significant.In addition,by studying the variation of strain energy density,it is found that the stress amplitude mainly promotes the fatigue damage,while the mean stress leads to the ratcheting damage.In addition,fractographic observation shows that the crack initiates in the brittle metal compound at the interface,and the steel has higher resistance to crack propagation.Finally,the accuracy of life prediction model considering ratcheting effect is discussed in detail,and a high-precision life prediction model directly based on mean stress and stress amplitude is proposed.
文摘This paper proposes to use the related party transactions’(RPT)budget completion ratio(BCR)as indicator of RPT’s execution quality.This paper studies BCR by defining budget ceiling through RPTs announcement and comparing the amount disclosed in annual report as budget execution result.Through statistical analysis of 285 RPT announcements,we classify RPT’s BCR into four benchmark grades.This paper sums up the BCR of RPT from the samples,and deduces moral obligation and moral judgement curve(OJ curve)in terms of BCR.OJ curve is the real dynamic equilibrium after the struggle agency problems.From our statistical results,we verified that Weitzman’s ratchet effect exists in the budget formulation of RPTs,and it is a solid proof of Weitzman’s ratchet effect applied to real business scenarios.The empirical results show ratchet effect exists in BCR of RPTs before and after the change from GEM board listing to main board listing in Hong Kong(Transfer).This paper also finds that it is significant to find the estimated actual amount in the coming year through the budget completion ratio(BCR)of RPT from last year.This paper is a pioneer to examine the execution quality of RPT by the means of(i)Weitzman’s Truth Inducing Model,(ii)BCR,and(iii)SGR as well as(iv)estimated actual amount.
基金supported by the National Natural Science Foundation of China (Grant No. 10825520)the National Basic Research Program of China (Grant No. 2007CB936000)Shanghai Leading Academic Discipline Project (Grant No. B111), and Shanghai Supercomputer Center of China
文摘Under the theory of ratchet effect for mesoand macro-scale systems, the additional perturbation with a long time correlation and the breaking of spatial inversion symmetry are two main ingredients to bring unidirected transportations. With the help of a simple model system, we show that a spatially asymmetric system of the nano-scale length may induce biased transportations under thermal noise.
基金supported by the National Natural Science Foundation of China(21774091(K.C.)and 21674078(W.T.))
文摘Time reversal asymmetry and spatial anisotropy are considered two prerequisites for Brownian ratchet.An intriguing realization can be achieved by placing an asymmetric gear in the suspension of motile rod-like bacteria.Usually,alignment interactions caused by anisotropic collisions or hydrodynamics would boost the ratchet effect.Here,we are concerned with a perfectly isotropic system,i.e.,symmetric gear immersed in a bath of spherical active Brownian particles.We find that,under certain conditions,kinetic symmetry-breaking arises spontaneously,i.e.,the symmetric gear keeps rotating in one direction.Unexpectedly,such ratchet phenomenon does not rely on the direct many-particle interactions and moreover the introduction of alignment interaction would counterintuitively prevent it from happening!Further investigation reveals that such spontaneous symmetry-breaking phenomenon shares similarities with the equilibrium phase transition of the Ising model.Our results provide new insights and enhance our understanding of the fundamental aspects of active ratchet phenomena.
基金supported by the National Natural Science Foundation of China(Grant No.12065008)the Key Project of Youth Science Foundation of Jiangxi Province(Grant No.20192ACBL21001)+2 种基金the Outstanding Youth Project of Jiangxi Province(Grant No.20192BCBL23007)supported by the National Natural Science Foundation of China(Grant No.11775190)supported by the National Natural Science Foundation of China(Grant No.11775035)。
文摘We describe an optomechanical ratchet scheme to realize nonreciprocal transmission of a light field, which is based on the bias of the optical cavity’s frequency spectrum caused by mechanical ratchet interactions. This approach to break the time-reversal symmetry of light propagation is universally valid in various optomechanical systems with ratchet-oscillator structures. We discuss specifically the implementation of an on-chip Casimir-ratchet optomechanical protocol and demonstrate the optical nonreciprocity with an extremely high isolation ratio and flexible controllability, which does not require external additional optical engineering. Our study opens a door for manipulating flexibly light propagation by using mechanical ratchet resonators, and has potential applications in the on-chip integration of nonreciprocal devices and harness of lateral Casimir forces.
