Biomedical subjects

Zhigang Zheng

Publications and source records attributed to Zhigang Zheng.

6 recordsLinked to original sources

PubMed2005

Deterministic directed transport of inertial particles in a flashing ratchet potential.

Deterministic directed transport of inertia particles in a periodically on-off ratchet potential is investigated. We find that the directed transport can be induced by a finite inertia; i.e., in the overdamped case, no directed motion of the system can be observed. It is shown that a critical threshold of the ratchet asymmetry is required for the system to achieve a net current. Directed transport can be greatly enhanced when the coupling strength of particles is increased. An appropriate match of the coupling, the flashing period, and the damping can give rise to the best efficiency of transport. The commensurate effect on the directed transport, which originates from the spatial competition between the period of the potential and the static length of the coupling, is analyzed.

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PubMed2003

Unexpected correspondence between noise-induced and master-slave complete synchronizations.

A comparison between noise-induced synchronization and master-slave (Pecora-Carroll) synchronization is investigated in this paper. We find an interesting correspondence between the effective driving variables of these two kinds of synchronizations in three-dimensional chaotic systems, when the systems have nonlinear terms in more than one equation. A study of the Lorenz model, the Hindmarsh-Rose neuron model, and the Hastings-Powell foodweb model is given to support this claim. It is a somewhat surprising result since these two kinds of synchronizations arise through different mechanisms. We also examine an exceptional case, where the nonlinear term of the system appears in a single equation, as in the Pikovsky-Rabinovich circuit model, and explain why the correspondence fails.

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PubMed2003

Detecting generalized synchrony: an improved approach.

We examine some of the difficulties involved in detecting generalized synchrony (GS) in systems that exhibit noninvertibility and/or wrinkling. These latter features severely hinder identification of GS by conventional techniques. It is shown that it is possible to greatly improve detection by reducing the pseudofalse neighbors effects. Here we propose the delta(p)-neighbor method to overcome the noninvertibility effect and the delta(p,q) method to detect GS in systems with wrinkled structures.

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PubMed2002

Analysis of generalized synchronization in directionally coupled chaotic phase-coherent oscillators by local minimal fluctuations.

The method of local-minimum fluctuation is proposed to analyze generalized synchronization in directionally coupled chaotic phase-coherent oscillators. It is shown that the emergence of generalized synchronization is manifested by the qualitative changes in the statistic of local minimum fluctuations of the receiver oscillator.

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PubMed2002

Collective directed transport of symmetrically coupled lattices in symmetric periodic potentials.

A mechanism responsible for the directed transport of symmetrically coupled lattices in a symmetric periodic potential is proposed. Under the action of an external wave that breaks the spatiotemporal symmetry and introduces inhomogeneities of the lattice, a net unidirectional current can be observed, originating from a collaboration of the lattice (periodic potential and mutual interactions) and the wave (amplitude, frequency, and phase shifts). Mode-locking induced resonant steps are observed and predicted. The directed transport can be optimized and furthermore controlled by suitably adjusting the parameters of the system.

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PubMed2002

Transitions from partial to complete generalized synchronizations in bidirectionally coupled chaotic oscillators.

Generalized synchronization in an array of mutually (bidirectionally) coupled nonidentical chaotic oscillators is studied. Coupled Lorenz oscillators and coupled Lorenz-Rossler oscillators are adopted as our working models. With increasing the coupling strengths, the system experiences a cascade of transitions from the partial to the global generalized synchronizations, i.e., different oscillators are gradually entrained through a clustering process. This scenario of transitions reveals an intrinsic self-organized order in groups of interacting units, which generalizes the idea of generalized synchronizations in drive-response systems.

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