3,015 research outputs found
Generalized Synchronization with Uncertain Parameters of Nonlinear Dynamic System via Adaptive Control
An adaptive control scheme is developed to study the generalized adaptive chaos synchronization with uncertain chaotic parameters behavior between two identical chaotic dynamic systems. This generalized adaptive chaos synchronization controller is designed based on Lyapunov stability theory and an analytic expression of the adaptive controller with its update laws of uncertain chaotic parameters is shown. The generalized adaptive synchronization with uncertain parameters between two identical new Lorenz-Stenflo systems is taken as three examples to show the effectiveness of the proposed method. The numerical simulations are shown to verify the results
Nonlinear Dynamic Analysis and Synchronization of Four-Dimensional Lorenz-Stenflo System and Its Circuit Experimental Implementation
Recently many chaotic systems’ circuits are designed to generate phenomenon of chaos signals. The ability to synchronize chaotic circuits opens a great number of ways to use them in application signals masking. In this paper, first a new nonlinear chaotic dynamical system had be design, analyze and build circuit. Second, using GYC, partial region stability theory is applied to adaptive control for two identical chaotic systems with uncertain parameters. The results of numerical simulation are performed to verify examples of the proposed nonlinear controllers
An Application of Nash-Moser Theorem to Smooth Solutions of One-Dimensional Compressible Euler Equation with Gravity
We study one-dimensional motions of polytropic gas governed by the
compressible Euler equations. The problem on the half space under a constant
gravity gives an equilibrium which has free boundary touching the vacuum and
the linearized approximation at this equilibrium gives time periodic solutions.
But it is not easy to justify the existence of long-time true solutions for
which this time periodic solution is the first approximation. The situation is
in contrast to the problem of free motions without gravity. The reason is that
the usual iteration method for quasilinear hyperbolic problem cannot be used
because of the loss of regularities which causes from the touch with the
vacuum. Interestingly, the equation can be transformed to a nonlinear wave
equation on a higher dimensional space, for which the space dimension, being
larger than 4, is related to the adiabatic exponent of the original
one-dimensional problem. We try to find a family of solutions expanded by a
small parameter. Applying the Nash-Moser theory, we justify this expansion.The
application of the Nash-Moser theory is necessary for the sake of conquest of
the trouble with loss of regularities, and the justification of the
applicability requires a very delicate analysis of the problem
Seismic Fragility Analysis for Sheet Pile Wharves — Case Study of the Hualien Harbor in Taiwan
The seismic fragility curves represent the conditional probabilities that the structural damage meets or exceeds the specified damage states at various levels of the ground motion parameters, such as peak ground acceleration (PGA). In this study, the seismic fragility analysis for the sheet pile wharves of the Hualien Harbor in Taiwan was performed. The finite element analysis software PLAXIS was adopted for the nonlinear dynamic analysis. The time histories of several representative earthquake events that actually occurred in Taiwan, including the 1999 Chi-Chi Earthquake, were scaled to various PGA levels as the input motions. Then the seismic responses of the sheet pile wharves subjected to these earthquakes of different intensities were obtained. It is assumed that the maximum residual displacement at the top of the sheet pile wall is lognormal distributed. Thus, the conditional exceedance probabilities of each specified damage state at different levels of PGA were estimated according to the displacement threshold value of each damage state, and the fragility curves were deduced. Moreover, these fragility curves were parameterized assuming they can be well approximated by the lognormal cumulative probability function, which is important for the rapid estimation of earthquake loss
Travelling wave solutions for Kolmogorov-type delayed lattice reaction–diffusion systems
[[abstract]]This work investigates the existence and non-existence of travelling wave solutions for Kolmogorov-type delayed lattice reaction–diffusion systems. Employing the cross iterative technique coupled with the explicit construction of upper and lower solutions in the theory of quasimonotone dynamical systems, we can find two threshold speeds c∗ and c∗ with c∗≥c∗>0. If the wave speed is greater than c∗, then we establish the existence of travelling wave solutions connecting two different equilibria. On the other hand, if the wave speed is smaller than c∗, we further prove the non-existence result of travelling wave solutions. Finally, several ecological examples including one-species, two-species and three-species models with various functional responses and time delays are presented to illustrate the analytical results.[[notice]]補æ£å®Œç•¢[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]紙本[[countrycodes]]GB
Antcin K, a Triterpenoid Compound from Antrodia camphorata
The purpose of this study was to screen firstly the potential effects of antcin K (AnK), the main constituent of the fruiting body of Antrodia camphorata, in vitro and further evaluate the activities and mechanisms in high-fat-diet- (HFD-) induced mice. Following 8-week HFD-induction, mice were treated with AnK, fenofibrate (Feno), metformin (Metf), or vehicle for 4 weeks afterward. In C2C12 myotube cells, the membrane GLUT4 and phospho-Akt expressions were higher in insulin and AnK-treated groups than in the control group. It was observed that AnK-treated mice significantly lowered blood glucose, triglyceride, total cholesterol, and leptin levels in AnK-treated groups. Of interest, AnK at 40 mg/kg/day dosage displayed both antihyperglycemic effect comparable to Metf (300 mg/kg/day) and antihypertriglyceridemic effect comparable to Feno (250 mg/kg/day). The combination of significantly increased skeletal muscular membrane expression levels of glucose transporter 4 (GLUT4) but decreased hepatic glucose-6-phosphatase (G6 Pase) mRNA levels by AnK thus contributed to a decrease in blood glucose levels. Furthermore, AnK enhanced phosphorylation of AMP-activated protein kinase (phospho-AMPK) expressions in the muscle and liver. Moreover, AnK treatment exhibited inhibition of hepatic fatty acid synthase (FAS) but enhancement of fatty acid oxidation peroxisome proliferator-activated receptor α (PPARα) expression coincident with reduced sterol response element binding protein-1c (SREBP-1c) mRNA levels in the liver may contribute to decreased plasma triglycerides, hepatic steatosis, and total cholesterol levels. The present findings indicate that AnK displays an advantageous therapeutic potential for the management of type 2 diabetes and hyperlipidemia
Effects Of Dispersive 2-Photon Transitions On Femtosecond Pulse-Propagation In Semiconductor Wave-Guides
It is demonstrated that the frequency spectrum of femtosecond pulses becomes highly asymmetric when propagating as transverse magnetic modes in semiconductor multiple quantum well channel waveguides at photon energies near half the band gap. Calculations based on the frequency dispersion in two-photon transitions provide results consistent with the experiment
Role of fibronectin deposition in cystogenesis of Madin-Darby canine kidney cells
Role of fibronectin deposition in cystogenesis of Madin-Darby canine kidney cells.BackgroundMadin-Darby canine kidney (MDCK) cells cultured within collagen I gel exhibit clonal growth and form spherical multicellular cysts. The cyst-lining epithelial cells are polarized with the basolateral surface in contact with the collagen gel and the apical surface facing the lumen. To understand whether MDCK cysts construct the basal lamina, we characterized the composition of the extracellular matrix deposited by MDCK cysts. The cyst-lining cells produced an apparently incomplete basal lamina containing a discontinuous laminin substratum. In addition, the basal cell surface of the cyst was surrounded by a thick layer of fibronectin. This study was conducted to delineate the role of fibronectin deposition in cystogenesis.MethodsMDCK cells cultured in collagen gel were employed. We first used Arg-Gly-Asp (RGD) peptides containing disintegrin rhodostomin to disturb the interaction between fibronectin and the cell surface integrin. We then established several stable transfectants expressing the fibronectin antisense RNA and with which to directly examine the role of fibronectin in cystogenesis.ResultsRhodostomin markedly decreased the growth rates of the MDCK cyst, suggesting the importance of a normal interaction between fibronectin and integrins. The stable transfectants overexpressing the fibronectin antisense RNA exhibited relatively lower levels of fibronectin and markedly lower cyst growth rates than the control clone. The lower growth rate was correlated with an increase in collagen gel-induced apoptosis.ConclusionsThe results indicate that the deposition of fibronectin underlying the cyst-lining epithelium serves to prevent apoptosis induced by three-dimensional collagen gel cultures, and hence facilitates cyst growth of MDCK cells
Holographic Gauge Theory with Maxwell Magnetic Field
We first apply the transformation of mixing azimuthal with wrapped coordinate
to the 11D M-theory with a stack N M5-branes to find the spacetime of a stack
of N D4-branes with magnetic field in 10D IIA string theory, after the
Kaluza-Klein reduction. In the near-horizon limit the background becomes the
Melvin magnetic field deformed . Although the solution
represents the D-branes under the Melvin RR one-form we use a simple
observation to see that it also describes the solution of D-branes under the
Maxwell magnetic field. As the magnetic field we consider is the part of the
background itself we have presented an alternative to previous literature,
because our method does not require the assumption of negligible back reaction.
Next, we use the found solution to investigate the meson property through D4/D8
system (Sakai-Sugimoto model) and compare it with those studied by other
authors. Finally, we present a detailed analysis about the Wilson loop therein
and results show that the external Maxwell magnetic field will enhance the
quark-antiquark potential.Comment: Latex 14 pp, add fi
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