共查询到20条相似文献,搜索用时 15 毫秒
1.
The transport properties of coupled Brownian particles in a two-dimensional rocking ratchet are investigated via Langevin simulation. The results show that the average center-of-mass velocity is multi-peaks function of the frequency of the driving force. Furthermore, in the 2D coupled Brownian motor system there are the collective effect and ratchet behavior, which can switch depending on the frequency of driving force. It turns out that the cooperative effect between the interaction of coupled particles and external rocking driving force facilitates collective directional motion and energy conversion. 相似文献
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《Physica A》2005,350(1):122-130
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We theoretically study the cooperative behavior of cytoskeletal filaments in motility assays in which immobilized motor proteins bind the filaments to substrate surfaces and actively pull them along these surfaces. Because of the mutual exclusion of the filaments, the coupled dynamics of filaments, motor heads, and motor tails leads to a nonequilibrium phase transition which generalizes the isotropic-nematic phase transition of the corresponding equilibrium system, the hard-rod fluid. Langevin dynamics simulations show that the motor activity enhances the tendency for nematic ordering. We develop a quantitative theory for the location of the phase boundary as a function of motor density. At high detachment forces of motors, we also observe filament clusters arising from blocking effects. 相似文献
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F. Ziebert M. Vershinin S. P. Gross I. S. Aranson 《The European physical journal. E, Soft matter》2009,28(4):401-409
We study the alignment of polar biofilaments, such as microtubules and actin, subject to the action of multiple molecular
motors attached simultaneously to more than one filament. Focusing on a paradigm model of only two filaments interacting with
multiple motors, we were able to investigate in detail the alignment dynamics. While almost no alignment occurs in the case
of a single motor, the filaments become rapidly aligned due to the collective action of the motors. Our analysis shows that
the alignment time is governed by the number of bound motors and the magnitude of the motors’ stepping fluctuations. We predict
that the time scale of alignment is in the order of seconds, much faster than that reported for passive crosslink-induced
bundling. In vitro experiments on the alignment of microtubules by multiple-motor covered beads are in qualitative agreement. We also discuss
another mode of fast alignment of filaments, namely the cooperation between motors and passive crosslinks. 相似文献
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We study the chaotic behavior of order parameters in two coupled ensembles of self-sustained oscillators. Coupling within each of these ensembles is switched on and off alternately, while the mutual interaction between these two subsystems is arranged through quadratic nonlinear coupling. We show numerically that in the course of alternating Kuramoto transitions to synchrony and back to asynchrony, the exchange of excitations between two subpopulations proceeds in such a way that their collective phases are governed by an expanding circle map similar to the Bernoulli map. We perform the Lyapunov analysis of the dynamics and discuss finite-size effects. 相似文献
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Xiao-Bin Dai 《Physica A》2007,383(2):624-630
Using molecular dynamics (MD) simulation and evolutionary game theory, we incorporate the spacial structure of individuals into the study of the behaviors of cooperation, by adopting the prisoner's dilemma and snowdrift game as metaphors of cooperation between unrelated individuals. The results show that the introduction of spacial structure enhances cooperation using the strategy of prisoner's dilemma while does not make much changes to the cooperation if the strategy of snowdrift game is used. It is also found that our model is a meta-phase between regular ring graph model and complex network model. And the “activity of players” T* we introduced makes our simulation much more closer to real world problems. 相似文献
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O. Petracic X. Chen S. Bedanta W. Kleemann S. Sahoo S. Cardoso P.P. Freitas 《Journal of magnetism and magnetic materials》2006
Discontinuous magnetic multilayers [CoFe/Al2O3] are studied by use of magnetometry, susceptometry and numeric simulations. Soft ferromagnetic Co80Fe20 nanoparticles are embedded in a diamagnetic insulating a-Al2O3 matrix and can be considered as homogeneously magnetized superspins exhibiting randomness of size (viz. moment), position and anisotropy. Lacking intra-particle core-surface ordering, generic freezing processes into collective states rather than individual particle blocking are encountered. With increasing particle density one observes first superspin glass and then superferromagnetic domain state behavior. The phase diagram resembles that of a dilute disordered ferromagnet. Criteria for the identification of the individual phases are given. 相似文献
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Jens Michaelis Adam Muschielok Joanna Andrecka Wolfgang Kügel Jeffrey R. Moffitt 《Physics of life reviews》2009,6(4):250-266
Most of the essential cellular processes such as polymerisation reactions, gene expression and regulation are governed by mechanical processes. Controlled mechanical investigations of these processes are therefore required in order to take our understanding of molecular biology to the next level. Single-molecule manipulation and force spectroscopy have over the last 15 years been developed into extremely powerful techniques. Applying these techniques to the investigation of proteins and DNA molecules has led to a mechanistic understanding of protein function on the level of single molecules. As examples for DNA based molecular machines we will describe single-molecule experiments on RNA polymerases as well as on the packaging of DNA into a viral capsid—a process that is driven by one of the most powerful molecular motors. 相似文献
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Elastically coupled molecular motors 总被引:3,自引:0,他引:3
A. Vilfan E. Frey F. Schwabl 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,3(4):535-546
We study the influence of filament elasticity on the motion of collective molecular motors. It is found that for a backbone
flexibility exceeding a characteristic value (motor stiffness divided through the mean displacement between attached motors),
the ability of motors to produce force reduces as compared to rigidly coupled motors, while the maximum velocity remains unchanged.
The force-velocity-relation in two different analytic approximations is calculated and compared with Monte-Carlo simulations.
Finally, we extend our model by introducing motors with a strain-dependent detachment rate. A remarkable crossover from the
nearly hyperbolic shape of the Hill curve for stiff backbones to a linear force-velocity relation for very elastic backbones
is found. With realistic model parameters we show that the backbone flexibility plays no role under physiological conditions
in muscles, but it should be observable in certain in vitro assays.
Received: 27 November 1997 / Revised: 20 February 1998 / Accepted: 27 March 1998 相似文献
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The European Physical Journal E - 相似文献
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B.L. Feringa N. Koumura R.A. van Delden M.K.J. ter Wiel 《Applied Physics A: Materials Science & Processing》2002,75(2):301-308
Technology is omnipresent in our modern-day society and it is hard to imagine a world without machines, computers or robots.
One of the main current scientific challenges is the bottom-up construction of systems that represent nanosize analogues of
switches, devices and motors. Our efforts in this area have focussed on the construction of devices based on sterically overcrowded
alkenes. In this paper, we present our ongoing research on the construction of binary molecular switches, which has recently
led to genuine molecular motors. The control of chirality in a molecular switching system allows interconversion between molecules
of opposite helicity using different wavelengths of light. Such bistable chiral switches are of potential use in optical data
storage and processing at the molecular level. The control of molecular chirality is even more subtle in the case of molecular
motor systems. The exquisite control of chirality using light as an energy source has resulted in a controlled, repetitive
360° unidirectional rotation in two generations of molecular motor systems.
Received: 21 January 2002 / Accepted: 11 February 2002 / Published online: 22 April 2002 相似文献
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An outstanding open problem in nanoscience is how to control the motion of tiny particles. Ratchetlike devices, inspired by biological motors, have been proposed as a way to achieve this goal. However, the net directed transport is almost suppressed if the diffusing particles are weakly coupled to the underlying spatially asymmetric substrate. Here we show how adding particles of an auxiliary species, that interact with both the primary particles of interest and the substrate, provides a controlled enhancement of the flow for both species. These can move either together or in opposite directions, depending upon the strength of the interaction, and whether it is attractive or repulsive. 相似文献
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S. Taneri M. Cemal Yalabık 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(3):403-407
We implement a model to represent the effect of the deformation of the backbone of a system of motor proteins while sliding
on a track filament. This model incorporates a nearest neighbor interaction term among the motors for the deformation energy.
Correlations induced by this term result in increased motor force for inter-particle distances small compared to the ratchet
period.
Received 20 February 2001 and Received in final form 31 May 2001 相似文献
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N. Xu 《Acta Physica Hungarica A》2003,17(2-4):229-235
We discuss the strong collective flow effects, 〈v 2〉 and 〈β t 〉, observed at RHIC (√ s NN=130 GeV). We argue that part of the collectivity could have already developed at partonic stage. To ‘see’ the partonic effects directly, measurements of multi-strange baryons like Ξ, Ω and charmed particles like J/ψ transverse momentum distributions are important. They provide one of the possible keys to the discovery of collective modes with the partonic (quarks and gluons) degrees of freedom. 相似文献
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A statistical two-dimensional interacting line model is defined in terms of three parameters describing the line stiffness, the line-line interaction and an external restoring force. It describes the collective properties of various physical systems like reconstructing surfaces, disordering stepped surfaces and adsorbed interacting polymers. The statistical properties are calculated by a Monte-Carlo method. The resulting phase diagram is presented for various parameters and an Ising critical behaviour at the phase boundaries is established. For the case of competing interactions a disorder line is found. 相似文献
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We have studied the collective behaviour of a one-dimensional ring of cells for conditions when the individual uncoupled cells
show stable, bistable and oscillatory dynamics. We show that the global dynamics of this model multicellular system depends
on the system size, coupling strength and the intrinsic dynamics of the cells. The intrinsic variability in dynamics of the
constituent cells are suppressed to stable dynamics, or modified to intermittency under different conditions. This simple
model study reveals that cell–cell communication, system size and intrinsic cellular dynamics can lead to evolution of collective
dynamics in structured multicellular biological systems that is significantly different from its constituent single-cell behaviour. 相似文献