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学者姓名:李静
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Abstract :
This study investigates the impact of an inclined magnetic field (MHD) on entropy generation in double diffusive natural convective flow in a wavy enclosure filled with a non-Newtonian Casson fluid. The Galerkin Finite Element Method (GFEM) is employed to numerically solve the standard formulation, utilizing quadratic polynomials for momentum interpolation and a linear interpolating function for model approximation. The discretized system is resolved using Newton's approach and PARDISO's matrix factorization. Through simulations of varying ranges of Rayleigh numbers (1e(3) <= Ra <= 1e(5)), Casson parameter (0.1 <= beta <= 10), Hartmann numbers (0 <= Ha <= 40), Lewis numbers (0.1 <= Le <= 5), and inclined angle gamma (0 <= gamma <= 60o), the study provides valuable insights into the behavior of double diffusive natural convection in the wavy enclosure. Isotherms, iso-concentration contours, and streamlines are analyzed to assess different input distributions, and the study presents graphical representations and tabular data on heat transfer, mass transfer rate, and entropy production.
Keyword :
wavy cavity wavy cavity Casson fluid Casson fluid GFEM GFEM magnetic field (MHD) magnetic field (MHD) double diffusive double diffusive
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GB/T 7714 | Chuhan, Imran Shabir , Li, Jing , Guo, Ziyu et al. Entropy optimization of MHD non-Newtonian fluid in a wavy enclosure with double diffusive natural convection [J]. | NUMERICAL HEAT TRANSFER PART A-APPLICATIONS , 2023 . |
MLA | Chuhan, Imran Shabir et al. "Entropy optimization of MHD non-Newtonian fluid in a wavy enclosure with double diffusive natural convection" . | NUMERICAL HEAT TRANSFER PART A-APPLICATIONS (2023) . |
APA | Chuhan, Imran Shabir , Li, Jing , Guo, Ziyu , Shahzad, Hasan , Yaqub, Muhammad . Entropy optimization of MHD non-Newtonian fluid in a wavy enclosure with double diffusive natural convection . | NUMERICAL HEAT TRANSFER PART A-APPLICATIONS , 2023 . |
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Purpose This paper propose a grounded-type DVA attached to a damped primary system, which can effectively suppress the vibration amplitudes by introducing a lever, focusing on the optimal design of the novel DVA. It can be utilized to the simplified model of a damped spacecraft or stay cable of cable-stayed bridges. Methods The design of DVA considers H-infinity, and H-2 optimization criteria, and defines performance indicators separately. In the H-infinity, optimization, we couple generalized fixed-point theory (GFPT) and perturbation method (PM) with particle swarm optimization (PSO) algorithm to minimize the maximum amplitude amplification factor of primary system, so that the amplitudes at two fixed points are close to the same horizontal line. Nevertheless, in the H-2 optimization, the GFPT and PM are combined with Newton's method to minimize the power input to primary system. Results The numerical results indicate the consistency and effectiveness of the two optimization criteria. Compared with other classical models, the effects of different grounded stiffness ratios on the amplitude frequency responses, time histories, and vibration energies of the primary system subjected to harmonic excitation and random excitation, respectively, as well as the vibration reduction effect, are studied. Conclusions Numerical simulations display with the positive grounded stiffness, the proposed DVA outperform the existing DVAs with same mass, damping, and stiffness under the harmonic excitation and random excitation. The results can provide theoretical and computational guidance for the optimal design of DVA.
Keyword :
Damped primary system Damped primary system Dynamic vibration absorber Dynamic vibration absorber Generalized fixed-point theory Generalized fixed-point theory Optimization algorithm Optimization algorithm
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GB/T 7714 | Li, Jing , Zhao, Hongzhen , Zhu, Shaotao et al. H∞ and H2 Optimization of the Grounded-Type DVA Attached to Damped Primary System Based on Generalized Fixed-Point Theory Coupled Optimization Algorithm [J]. | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES , 2023 . |
MLA | Li, Jing et al. "H∞ and H2 Optimization of the Grounded-Type DVA Attached to Damped Primary System Based on Generalized Fixed-Point Theory Coupled Optimization Algorithm" . | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES (2023) . |
APA | Li, Jing , Zhao, Hongzhen , Zhu, Shaotao , Yang, Xiaodong . H∞ and H2 Optimization of the Grounded-Type DVA Attached to Damped Primary System Based on Generalized Fixed-Point Theory Coupled Optimization Algorithm . | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES , 2023 . |
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Based on the relevant theories of M-matrix and the Lyapunov stability technique, this paper investigates the multistability of equilibrium points and periodic solutions for Clifford-valued memristive Cohen-Grossberg neural networks. With the help of Cauchy convergence criterion, the exponential stability inequality is derived. The system has [Pi(A)(K-A+1)](n) locally exponentially stable equilibrium points and periodic solutions, which greatly increases the number of solutions compared with the existing Cohen-Grossberg neural networks, where the K-A is a Clifford-valued and there is no limitation of linearity and monotonicity for activation functions. Furthermore, the attraction basins of stable periodic solutions are obtained, and it is proved that the basins can be enlarged. It is worth mentioning that the results can also be used to discuss the multistability of equilibrium points, periodic solutions, and almost periodic solutions for real-valued, complex-valued, and quaternion-valued memristive Cohen-Grossberg neural networks. Finally, two numerical examples with simulations are taken to verify the theoretical analysis.
Keyword :
multistability multistability Clifford-valued Clifford-valued equilibrium points equilibrium points memristive Cohen-Grossberg neural networks memristive Cohen-Grossberg neural networks periodic solutions periodic solutions
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GB/T 7714 | Li, Jing , Zhao, Hongzhen , Zhang, Yan et al. Multistability of equilibrium points and periodic solutions for Clifford-valued memristive Cohen-Grossberg neural networks with mixed delays [J]. | MATHEMATICAL METHODS IN THE APPLIED SCIENCES , 2023 , 47 (4) : 2679-2701 . |
MLA | Li, Jing et al. "Multistability of equilibrium points and periodic solutions for Clifford-valued memristive Cohen-Grossberg neural networks with mixed delays" . | MATHEMATICAL METHODS IN THE APPLIED SCIENCES 47 . 4 (2023) : 2679-2701 . |
APA | Li, Jing , Zhao, Hongzhen , Zhang, Yan , Zhu, Shaotao , Zhang, Yuzhan . Multistability of equilibrium points and periodic solutions for Clifford-valued memristive Cohen-Grossberg neural networks with mixed delays . | MATHEMATICAL METHODS IN THE APPLIED SCIENCES , 2023 , 47 (4) , 2679-2701 . |
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In this paper, we investigate the asymptotical stability and synchronization of fractional neural networks. Multiple time-varying delays and distributed delays are taken into consideration simultaneously. First, by applying the Banach's fixed point theorem, the existence and uniqueness of fractional delayed neural networks are proposed. Then, to guarantee the asymptotical stability of the demonstrated system, two sufficient conditions are derived by integral-order Lyapunov direct method. Furthermore, two synchronization criteria are presented based on the adaptive controller. The above results significantly generalize the existed conclusions in the previous works. At last, numerical simulations are taken to check the validity and feasibility of the achieved methods.
Keyword :
Distributed delays Distributed delays Lyapunov-Krasovskii function Lyapunov-Krasovskii function Fractional neural networks Fractional neural networks Asymptotical stability and synchronization Asymptotical stability and synchronization Multiple time-varying delays Multiple time-varying delays
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GB/T 7714 | Zhang, Yufeng , Li, Jing , Zhu, Shaotao et al. Asymptotical stability and synchronization of Riemann-Liouville fractional delayed neural networks [J]. | COMPUTATIONAL & APPLIED MATHEMATICS , 2023 , 42 (1) . |
MLA | Zhang, Yufeng et al. "Asymptotical stability and synchronization of Riemann-Liouville fractional delayed neural networks" . | COMPUTATIONAL & APPLIED MATHEMATICS 42 . 1 (2023) . |
APA | Zhang, Yufeng , Li, Jing , Zhu, Shaotao , Wang, Hongwu . Asymptotical stability and synchronization of Riemann-Liouville fractional delayed neural networks . | COMPUTATIONAL & APPLIED MATHEMATICS , 2023 , 42 (1) . |
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In this paper, we study the bifurcation of periodic orbits for high-dimensional piecewise smooth near integrable systems defined in three regions separated by two switching manifolds. We assume that the unperturbed system has a family of periodic orbits which cross two switching manifolds transversely. The expression of Melnikov function is derived based on the first integral. And the conditions of periodic orbits bifurcated from a family of periodic orbits for the high-dimensional piecewise smooth near integrable system are obtained. The theoretical results are applied to the bifurcation analysis of periodic orbits of two-degree-of-freedom piecewise smooth system of nonlinear energy sink. The periodic orbits configurations are presented with numerical method and the number of periodic orbits is three. (c) 2022 Elsevier B.V. All rights reserved.
Keyword :
High -dimensional systems High -dimensional systems Melnikov method Melnikov method Bifurcation of periodic orbits Bifurcation of periodic orbits Piecewise smooth Piecewise smooth
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GB/T 7714 | Li, Jing , Guo, Ziyu , Zhu, Shaotao et al. Bifurcation of periodic orbits and its application for high-dimensional piecewise smooth near integrable systems with two switching manifolds [J]. | COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION , 2023 , 116 . |
MLA | Li, Jing et al. "Bifurcation of periodic orbits and its application for high-dimensional piecewise smooth near integrable systems with two switching manifolds" . | COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION 116 (2023) . |
APA | Li, Jing , Guo, Ziyu , Zhu, Shaotao , Gao, Ting . Bifurcation of periodic orbits and its application for high-dimensional piecewise smooth near integrable systems with two switching manifolds . | COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION , 2023 , 116 . |
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Abstract :
This paper analytically and numerically investigates the dynamical characteristics of a fractional Duffing-van der Pol oscillator with two periodic excitations and the distributed time delay. First, we consider the pitchfork bifurcation of the system driven by both a high-frequency parametric excitation and a low-frequency external excitation. Utilizing the method of direct partition of motion, the original system is transformed into an effective integer-order slow system, and the supercritical and subcritical pitchfork bifurcations are observed in this case. Then, we study the chaotic behavior of the system when the two excitation frequencies are equal. The necessary condition for the existence of the horseshoe chaos from the homoclinic bifurcation is obtained based on the Melnikov method. Besides, the parameters effects on the routes to chaos of the system are detected by bifurcation diagrams, largest Lyapunov exponents, phase portraits, and Poincare maps. It has been confirmed that the theoretical predictions achieve a high coincidence with the numerical results. The techniques in this paper can be applied to explore the underlying bifurcation and chaotic dynamics of fractional-order models.
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GB/T 7714 | Zhang, Yufeng , Li, Jing , Zhu, Shaotao et al. Bifurcation and chaos detection of a fractional Duffing-van der Pol oscillator with two periodic excitations and distributed time delay [J]. | CHAOS , 2023 , 33 (8) . |
MLA | Zhang, Yufeng et al. "Bifurcation and chaos detection of a fractional Duffing-van der Pol oscillator with two periodic excitations and distributed time delay" . | CHAOS 33 . 8 (2023) . |
APA | Zhang, Yufeng , Li, Jing , Zhu, Shaotao , Zhao, Hongzhen . Bifurcation and chaos detection of a fractional Duffing-van der Pol oscillator with two periodic excitations and distributed time delay . | CHAOS , 2023 , 33 (8) . |
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Abstract :
Dynamic vibration absorbers (DVAs) are widely used in engineering practice because of their good vibration control performance. Structural design or parameter optimization could improve its control efficiency. In this paper, the viscoelastic Maxwell-type DVA model with an inerter and multiple stiffness springs is investigated with the combination of the traditional theory and an intelligent algorithm. Firstly, the expressions and approximate optimal values of the system parameters are obtained using the fixed-point theory to deal with the H infinity optimization problem, which can provide help with the range of parameters in the algorithm. Secondly, we innovatively introduce the particle swarm optimization (PSO) algorithm to prove that the algorithm could adjust the value of the approximate solution to minimize the maximum amplitude by analyzing and optimizing the single variable and four variables. Furthermore, the validity of the parameters is further verified by simulation between the numerical solution and the analytical solution using the fourth-order Runge-Kutta method. Finally, the DVA demonstrated in this paper is compared with typical DVAs under random excitation. The timing sequence and variances, as well as the decreased ratios of the displacements, show that the presented DVA has a more satisfactory control performance. The inerter and negative stiffness spring can indeed bring beneficial effects to the vibration absorber. Remarkably, the intelligent algorithm can make the resonance peaks equal in the parameter optimization of the vibration absorber, which is quite difficult to achieve with theoretical methods at present. The results may provide a theoretical and computational basis for the optimization design of DVA.
Keyword :
dynamic vibration absorber dynamic vibration absorber inerter inerter Maxwell-type Maxwell-type particle swarm optimization algorithm particle swarm optimization algorithm negative stiffness negative stiffness
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GB/T 7714 | Chen, Yuying , Li, Jing , Zhu, Shaotao et al. Further Optimization of Maxwell-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Spring Using Particle Swarm Algorithm [J]. | MATHEMATICS , 2023 , 11 (8) . |
MLA | Chen, Yuying et al. "Further Optimization of Maxwell-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Spring Using Particle Swarm Algorithm" . | MATHEMATICS 11 . 8 (2023) . |
APA | Chen, Yuying , Li, Jing , Zhu, Shaotao , Zhao, Hongzhen . Further Optimization of Maxwell-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Spring Using Particle Swarm Algorithm . | MATHEMATICS , 2023 , 11 (8) . |
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Abstract :
The dynamic vibration absorber (DVA) is widely used in engineering models with complex vibration modes. The research on the stability and periodic motions of the DVA model plays an important role in revealing its complex vibration modes and energy transfer. The aim of this paper is to study the stability and periodic motions of a two-degrees-of-freedom system coupled with an encapsulated nonsmooth dynamic vibration absorber under low-frequency forced excitation. Based on the slow-fast method, the model is transformed into a six-dimensional piecewise smooth system coupling two time scales. The existence and stability of the admissible equilibrium points for the model are discussed under different parameter conditions. Based on the first integrals, the Melnikov vector function of the nonsmooth dynamic vibration absorber model is calculated. The existence and number of periodic orbits bifurcated from a family of periodic orbits under different parameters are discussed. The phase diagram configuration of periodic orbits is given based on numerical simulation. The results obtained in this paper offer a new perspective for vibration analysis and parameter control for nonsmooth dynamic vibration absorbers.
Keyword :
nonsmooth dynamic vibration absorber nonsmooth dynamic vibration absorber periodic motions periodic motions Melnikov function Melnikov function stability stability
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GB/T 7714 | Guo, Ziyu , Li, Jing , Zhu, Shaotao et al. Stability and Periodic Motions for a System Coupled with an Encapsulated Nonsmooth Dynamic Vibration Absorber [J]. | APPLIED SCIENCES-BASEL , 2023 , 13 (15) . |
MLA | Guo, Ziyu et al. "Stability and Periodic Motions for a System Coupled with an Encapsulated Nonsmooth Dynamic Vibration Absorber" . | APPLIED SCIENCES-BASEL 13 . 15 (2023) . |
APA | Guo, Ziyu , Li, Jing , Zhu, Shaotao , Zhang, Yufeng . Stability and Periodic Motions for a System Coupled with an Encapsulated Nonsmooth Dynamic Vibration Absorber . | APPLIED SCIENCES-BASEL , 2023 , 13 (15) . |
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Dynamic vibration absorbers (DVAs) are extensively used in the prevention of building and bridge vibrations, as well as in vehicle suspension and other fields, due to their excellent damping performance. The reliable optimization of DVA parameters is key to improve their performance. In this paper, an H-8 optimization problem of a novel three-element-type DVA model including an inerter device and a grounded negative stiffness spring is studied by combining a traditional theory and an intelligent algorithm. Firstly, to ensure the system's stability, the specific analytical expressions of the optimal tuning frequency ratio, stiffness ratio, and approximate damping ratio with regard to the mass ratio and inerter-mass ratio are determined through fixed-point theory, which provides an iterative range for algorithm optimization. Secondly, the particle swarm optimization (PSO) algorithm is used to further optimize the four parameters of DVA simultaneously. The effects of the traditional fixed-point theory and the intelligent PSO algorithm are comprehensively compared and analyzed. The results verify that the effect of the coupling of the traditional theory and the intelligent algorithm is better than that of fixed-point theory alone and can make the two resonance peaks on the amplitude-frequency response curves almost equal, which is difficult to achieve using fixed-point theory alone. Finally, we compare the proposed model with other DVA models under harmonic and random excitation. By comparing the amplitude-frequency curves, stroke lengths, mean square responses, time history diagrams, variances and decrease ratios, it is clear that the established DVA has a good vibration absorption effect. The research results provide theoretical and algorithm support for designing more effective DVA models of the same type in engineering applications.
Keyword :
three-element-type DVA three-element-type DVA negative stiffness negative stiffness particle swarm optimization algorithm particle swarm optimization algorithm H-8 optimization H-8 optimization inerter-mass inerter-mass
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GB/T 7714 | Gao, Ting , Li, Jing , Zhu, Shaotao et al. H-8 Optimization of Three-Element-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Based on the Particle Swarm Algorithm [J]. | ENTROPY , 2023 , 25 (7) . |
MLA | Gao, Ting et al. "H-8 Optimization of Three-Element-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Based on the Particle Swarm Algorithm" . | ENTROPY 25 . 7 (2023) . |
APA | Gao, Ting , Li, Jing , Zhu, Shaotao , Yang, Xiaodong , Zhao, Hongzhen . H-8 Optimization of Three-Element-Type Dynamic Vibration Absorber with Inerter and Negative Stiffness Based on the Particle Swarm Algorithm . | ENTROPY , 2023 , 25 (7) . |
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Abstract :
Fractional q-calculus plays an extremely important role in mathematics and physics. In this paper, we aim to investigate the existence of triple-positive solutions for nonlinear singular fractional q-difference equation boundary value problems at resonance by means of the fixed-point index theorem and the q-Laplace transform, where the nonlinearity f(t,u,v) permits singularities at t=0,1 and u=v=0. The obtained theorem is well illustrated with the aid of an example.
Keyword :
resonance resonance positive solutions positive solutions fixed-point index theorem fixed-point index theorem q-Laplace transform q-Laplace transform fractional q-difference equation fractional q-difference equation
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GB/T 7714 | Yu, Changlong , Li, Shuangxing , Li, Jing et al. Triple-Positive Solutions for a Nonlinear Singular Fractional q-Difference Equation at Resonance [J]. | FRACTAL AND FRACTIONAL , 2022 , 6 (11) . |
MLA | Yu, Changlong et al. "Triple-Positive Solutions for a Nonlinear Singular Fractional q-Difference Equation at Resonance" . | FRACTAL AND FRACTIONAL 6 . 11 (2022) . |
APA | Yu, Changlong , Li, Shuangxing , Li, Jing , Wang, Jufang . Triple-Positive Solutions for a Nonlinear Singular Fractional q-Difference Equation at Resonance . | FRACTAL AND FRACTIONAL , 2022 , 6 (11) . |
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