Z. Q. Wu

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A self-excited system involving a van der Pol-type damping and a hysteretic damper representing restoring force is investigated in this paper. The influence of external force on the dynamic behavior of the hysteretic system is analyzed in detail. Numerical simulations show that, under an external force, the original hysteretic system can exhibit the(More)
In this paper, a new method is proposed for controlling bifur-cations of nonlinear dynamical systems. This approach employs the idea used in deriving the transition variety sets of bifurca-tions with constraints to find the stability region of equilibrium points in parameter space. With this method, one can design, via a feedback control, appropriate(More)
LRP16 gene has been characterized as an estrogen-responsive gene. One 1/2ERE/GC-rich site was previously identified to be indispensable for -676/-214 (region A) fragment within LRP16 regulatory region to confer E2 action. Here, we report that -213/-24 fragment (region B) has higher E2-responsiveness than that of region A in MCF-7 cells, but not in HeLa(More)
A checklist of the fish of Poyang Lake Basin based on an extensive survey and literature review is presented. A total of 220 species and subspecies belonging to12 orders, 27 families and 100 genera, have been recorded. Of these, 131 species are endemic to China. Based on cluster analysis with presence-absence data, freshwater ecosystems in Jiangxi Province(More)
Morphometry of numerical density and electron probe X-ray quantitative microanalysis were used to measure the alterations in the number and calcium content of chromaffin granules in adrenal medulla cells during emergency reaction of restrained rats. It was found that both the alterations showed monotonic decrease during the period of restraint, but the rate(More)
In this paper, we introduce the concepts of cyclic weakly (ψ, φ)-contractive mappings and cyclic weakly (C, ψ, ϕ)-contractive mappings, and prove some fixed point theorems for such two types of mappings in complete partially ordered Menger PM-spaces. Some new results are obtained, which extend and generalize some fixed point results in metric and(More)
Some medical images have significantly high levels of brightness contrast: parts of the image may be very bright while others may be very dark. Global contrast enhancement often fails to provide clinicians with an image that facilitates the easy visualisation of all the required information, while traditional local contrast enhancement is computationally(More)
In this paper, we prove some new fixed point theorems for multi-valued mappings under new contractions by proposing a new class of functions. The results of this paper improve several results in the litera-tures. And we extend the results into metric-like spaces, which expand the application range of the results. In 1992, Matthews [13] proposed the concept(More)