检索结果-内蒙古大学图书馆

Nonlinear multi-point impacts of the bi-stable functional gradient magneto-electro-elastic plate: Interaction analysis and active control strategy based on bistable configuration

引用

Communications in Nonlinear science and Numerical simulation 2025年 148卷

作者： Li, Lizhi Ren, Yiru Nie, Lu State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Hunan Changsha410082 China College of Mechanical and Vehicle Engineering Hunan University Hunan Changsha410082 China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of Education Hunan University Hunan Changsha410082 China China Academy of Aerospace Science and Innovation Beijing 100086 China

Revealing the coupling correlations between stiffness nonlinearity and magneto-electro-mechanical effect in multi-point impacts contributes significantly to the advancement of intelligent morphing structures. Multi-point impact responses and active control of bi-stable functional gradient magneto-electro-elastic (FG-MEE) plates are investigated, focusing on influence mechanism of the active control performance and the bi-stable characteristics. Based on the Reddy high-order shear plate theory model, the nonlinear geometric relationship considering the bi-stable configuration is established, and the multi-point impact model is extended. To achieve efficient structural design in multi-point impacts, the active control strategy in multi-physics fields is introduced. In the multi-physical field, the nonlinear dynamic model for multi-point impact involving the bi-stable functionally graded magneto-electro-elastic plate is established. The expanded two-step perturbation method is proposed to solve the bi-stable configuration driven by the magneto-electro-mechanical effect. To obtain the approximate solution for the multi-point impact of the bi-stable FG-MEE plate, the extended two-step perturbation method-Galerkin method is further developed to the higher-order form. Ultimately, coupling correlations between stiffness nonlinearity and magneto-electro-mechanical effect in the multi-point impacts are systematically revealed, and the active control performance is evaluated under the influence of multi-point impact. © 2025 Elsevier B.V.

关键词： Galerkin methods

来源：评论

学校读者我要写书评

暂无评论

A SECOND-ORDER DYNAMICAL LOW-RANK MASS-LUMPED FINITE ELEMENT METHOD FOR THE ALLEN-CAHN EQUATION

arXiv

引用

arXiv 2025年

作者： Yang, Jun Yi, Nianyu Yin, Peimeng School of Mathematics and Computational Science Xiangtan University Xiangtan411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Xiangtan411105 China Department of Mathematical Sciences The University of Texas at El Paso El PasoTX79968 United States

In this paper, we propose a novel second-order dynamical low-rank mass-lumped finite element method for solving the Allen-Cahn (AC) equation, a semilinear parabolic partial differential equation. The matrix differential equation of the semi-discrete mass-lumped finite element scheme is decomposed into linear and nonlinear components using the second-order Strang splitting method. The linear component is solved analytically within a low-rank manifold, while the nonlinear component is discretized using a second-order augmented basis update & Galerkin (BUG) integrator, in which the S-step matrix equation is solved by the explicit 2-stage strong stability-preserving Runge-Kutta method. The algorithm has lower computational complexity than the full-rank mass-lump finite element method. The dynamical low-rank finite element solution is shown to conserve mass up to a truncation tolerance for the conservative Allen-Cahn equation. Meanwhile, the modified energy is dissipative up to a high-order error and is hence stable. Numerical experiments validate the theoretical results. Symmetry-preserving tests highlight the robustness of the proposed method for long-time simulations and demonstrate its superior performance compared to existing *** Codes 35K58, 65F55, 65M60, 65Y20 © 2025, CC BY-NC-ND.

关键词： Runge Kutta methods

来源：评论

学校读者我要写书评

暂无评论

Designing a minimal Landau model to stabilize desired quasicrystals

引用

Physical Review Research 2025年第2期7卷 023021-023021页

作者： Wei Si Shifeng Li Pingwen Zhang An-Chang Shi Kai Jiang School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Hunan 411105 China School of Mathematics and Statistics Wuhan University Wuhan 430072 China LMAM CAPT and School of Mathematical Sciences Peking University Beijing 100871 China Department of Physics and Astronomy McMaster University Hamilton L8S 4M1 Canada

Interparticle interactions with multiple length scales play a pivotal role in the formation and stability of quasicrystals. Choosing a minimal set of length scales to stabilize a given quasicrystal is a challenging problem. To address this challenge, we propose a symmetry-preserving screening method (SPSM) to design a Landau theory with a minimal number of length scales—referred to as the minimal Landau theory—that includes only the essential length scales necessary to stabilize quasicrystals. Based on a generalized multiple-length-scale Landau theory, SPSM first evaluates various spectral configurations of candidate structures under a hard constraint. It then identifies the configuration with the lowest free energy. Using this optimal configuration, SPSM calculates phase diagrams to explore the thermodynamic stability of desired quasicrystals. SPSM can design a minimal Landau theory capable of stabilizing the desired quasicrystals by incrementally increasing the number of length scales. Our application of SPSM has not only confirmed known behaviors in 10- and 12-fold quasicrystals but also led to a significant prediction that quasicrystals with 8-, 14-, 16-, and 18-fold symmetry could be stable within three-length-scale Landau models.

关键词： Quasicrystals

来源：评论

学校读者我要写书评

暂无评论

An integrated framework for river assimilative capacity allocation based on environmental fairness and efficiency trade-offs with a modified optimization model in a river basin

引用

Environmental Modelling and Software 2025年 191卷

作者： Yang, Zhimin Wang, Jiangying Li, Xiaoxuan Li, Chunhui Pu, Zaohong Hu, Jing Yi, Yujun Wang, Xuan Liu, Qiang Key Laboratory for Water and Sediment Sciences of Ministry of Education School of Environment Beijing Normal University Beijing100875 China School of Information Science and Engineering Hunan Normal University Hunan 410081 China State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing100875 China

The allocation of river assimilative capacity (RAC) remains a complex challenge due to the trade-offs between environmental fairness and efficiency. To address these issues, a novel integrated framework for the optimal allocation of RAC was proposed. The Luan River Basin in Chengde City, China, was selected as a case study. Hydrodynamic and advection-dispersion modules from the MIKE 11 model were implemented and then integrated into the RAC model. An orthogonal experimental method was used to identify significant factors influencing RAC, and three regulatory scenarios were designed. The environmental Gini coefficient (EGC) was modified using a probability distribution function to evaluate fairness-based allocation of RAC, and the environmental benefits were used to quantitatively measure efficiency-based allocation. Subsequently, a modified optimization model was developed to determine the optimal RAC allocation under three regulatory scenarios based on environmental fairness and efficiency trade-offs. Results showed that the initial state was the least favorable, with the lowest RAC and highest modified EGC. Under high regulation, the average modified EGC decreased by 68.97 %, 53.49 %, and 18.22 % compared to the initial state, low, and moderate regulation, respectively. High regulation was ideal for environmental fairness. However, when considering the trade-offs between fairness and efficiency, moderate regulation achieved the optimal allocation, minimizing the objective function by 68.64 % compared to high regulation. The study provides new insights into targeted RAC allocation strategies to promote fairness and maintain efficiency. © 2025 Elsevier Ltd

关键词： Normal distribution

来源：评论

学校读者我要写书评

暂无评论

Fractional coupled Halanay inequality and its applications

arXiv

引用

arXiv 2025年

作者： Van Thinh, La Tuan, Hoang The Wang, Dongling Yang, Yin Academy of Finance Le Van Hien Street Duc Thang Ward Bac Tu Liem District Hanoi Viet Nam Institute of Mathematics Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Hanoi10307 Viet Nam Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China

This paper introduces a generalized fractional Halanay-type coupled inequality, which serves as a robust tool for characterizing the asymptotic stability of diverse time fractional functional differential equations, particularly those exhibiting Mittag-Leffler type stability. Our main tool is a sub-additive property of Mittag-Leffler function and its optimal asymptotic decay rate estimation. Our results further optimize and improve some existing results in the literature. We illustrate two significant applications of this fractional Halanay-type inequality. Firstly, by combining our results in this work with the positive representation method positive representation of delay differential systems, we establish an asymptotic stability criterion for a category of linear fractional coupled systems with bounded delays. This criterion extends beyond the traditional boundaries of positive system theory, offering a new perspective on stability analysis in this domain. Secondly, through energy estimation, we establish the contractility and dissipativity of a class of time fractional neutral functional differential equations. Our analysis reveals the typical long-term polynomial decay behavior inherent in time fractional evolutionary equations, thereby providing a solid theoretical foundation for subsequent numerical investigations. © 2025, CC BY.

关键词： Asymptotic stability

来源：评论

学校读者我要写书评

暂无评论

A BDDC method for three-dimensional advection-diffusion problems with an adaptive coarse space

arXiv

引用

arXiv 2025年

作者： Peng, Jie Shu, Shi Wang, Junxian Zhong, Liuqiang College of Mathematics and Statistics Hengyang Normal University Hengyang421010 China School of Mathematical Sciences South China Normal University Guangzhou510631 China School of Mathematics and Computational Science Xiangtan University Xiangtan411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan411105 China

The solution of nonsymmetric positive definite (NSPD) systems for advection-diffusion problems is an important research topic in science and engineering. The adaptive BDDC method is a significant class of non-overlapping domain decomposition methods, which is often used for solving symmetric positive definite problems. In this paper, we apply the adaptive BDDC method to solve the NSPD systems of te advection-diffusion problems. Moreover, by designing a class of edge generalized eigenvalue problems based on prior selected primal constraints, the number of primal unknowns is further reduced. Numerical experiments have verified the effectiveness of the proposed methods. Copyright © 2025, The Authors. All rights reserved.

关键词： Domain decomposition methods

来源：评论

学校读者我要写书评

暂无评论

Lattice Boltzmann simulation reveals supercritical bifurcation in flow mode transitions of power-law fluids in the four-roll mill

arXiv

引用

arXiv 2025年

作者： Yu, Yuan Jiang, Xiao Gu, Qingqing Lin, Chuandong Zhu, Qingyong Yuan, Hai-Zhuan School of Mathematics and Computational Science Xiangtan University Xiangtan411105 China National Center for Applied Mathematics in Hunan Xiangtan411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan411105 China School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai519082 China School of Aeronautics and Astronautics Sun Yat-sen University Shenzhen518107 China

The four-roll mill has been traditionally viewed as a device generating simple extensional flow with a central stagnation point. Our systematic investigation using a two-relaxation-time regularized lattice Boltzmann (TRT-RLB) model reveals unexpected richness in the flow physics, identifying two previously unreported supercritical bifurcation modes: a quadrifoliate vortex mode featuring four symmetrical counter-rotating vortices, and a dumbbell-shaped quad-vortex mode where vortices detach from but remain symmetric about the stagnation point. The numerical framework, representing the first successful extension of TRT-RLB method to power-law fluid dynamics, enables comprehensive mapping of flow characteristics across Reynolds numbers (1 ≤ Re ≤ 50), power-law indices (0.7 ≤ n ≤ 1.3), and geometric configurations. The transition from quadrifoliate vortex mode exhibits distinct pathways depending on the power-law index: at relatively small n, the flow undergoes a direct supercritical bifurcation to simple extensional flow, while at relatively large n, it evolves through an intermediate dumbbell-shaped state. Among geometric parameters, the roller radius r emerges as the dominant factor controlling bifurcation points and vortex dimensions, whereas the roller-container gap δ exerts minimal influence on flow regimes. The transitions between flow modes can be precisely characterized through the evolution of vortex dimensions and velocity gradients at the stagnation point, providing quantitative criteria for flow regime identification. These findings enrich our fundamental understanding of bifurcation phenomena in extensional devices and provide quantitative guidelines for achieving desired flow patterns in four-roll mill applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Vortex flow

来源：评论

学校读者我要写书评

暂无评论

Magnetic Fluid Flows in Porous Media

引用

Chinese Physics Letters 2011年第8期28卷 198-201页

作者： LI Ming-Jun CHEN Liang Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105

The seepage law under a magnetic field is obtained by up-scaling the flow at the pore scale of rigid porous media,and the macroscopic equivalent model is also *** is proved that the macroscopic mass flow depends on the macroscopic magnetic force and the gradients of pressure and of magnetic pressure,as Zahn and Rosensweig have described in their *** permeability tensor is symmetric and positive.

关键词： macroscopic Porous magnetic

来源：评论

学校读者我要写书评

暂无评论

Mesh Quality and More Detailed Error Estimates of Finite Element Method

引用

高等学校计算数学学报（英文版） 2017年第2期10卷 420-436页

作者： Yunqing Huang Liupeng Wang Nianyu Yi Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Xiangtan Hunan 411105 China

In this paper,we study the role of mesh quality on the accuracy of linear finite element *** derive a more detailed error estimate,which shows explicitly how the shape and size of elements,and symmetry structure of mesh effect on the error of numerical *** computable parameters Ge and Gv are given to depict the cell geometry property and symmetry structure of the *** compare with the standard a priori error estimates,which only yield information on the asymptotic error behaviour in a global sense,our proposed error estimate considers the effect of local element geometry properties,and is thus more *** certain conditions,the traditional error estimates and supercovergence results can be derived from the proposed error ***,the estimators Ge and Gv are computable and thus can be used for predicting the variation of *** tests are presented to illustrate the performance of the proposed parameters Ge and Gv.

关键词： Finite element methods error estimation cell geometry mesh quality

来源：评论

学校读者我要写书评

暂无评论

Orientation construction and comparison of mercury removal sites by physical and chemical adsorption on cotton stalk biochar

引用

Fuel 2025年 398卷

作者： Li, Guoliang Wang, Shuxiao Wu, Qingru Yue, Tao Gao, Jiajia Tong, Yali Zhang, Mingyu Zhang, Lin Zhang, Chenyang Xie, Sizhe School of Energy and Environmental Engineering University of Science and Technology Beijing Beijing100083 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China Changsha County Urban Management Bureau Hunan Province Changsha410100 China

The capture of elemental mercury (Hg0) is the crucial step for synergetic control of mercury emission via dust removal equipment. Micropore structure, oxygen-containing groups and adding active elements are three key factors in the biochars activation for mercury capture. Previous studies usually focused on single modification factor. This study aims to evaluate and contrast the influence of the three key factors on the mercury capture of biochars. Physical activation (microwave and steam), H2O2 modification and NH4Cl impregnation were used to directionally develop pore structure, form new oxygen-containing groups and introduce halogen active sites. The testing results showed that physical activation causes distinct increase in the Vmicro ratio by 420 % yet just modest increase in the highest mercury removal efficiency (η) of C6W by only 43.0 %. The 30 % H2O2 modification and 5 % NH4Cl impregnation distinctly increased η by 82.6 % and 116.2 %, respectively. Moreover, synergetic activation of H2O2 modification with physical activation and that of NH4Cl impregnation with physical activation further increased η by 159.5 % and 180.6 %, respectively. The pore structure development was not the key factor in mercury removal, yet it improved the chemical modification effectiveness. Physicochemical characterization methods, molecular adsorption kinetic models and mercury desorption energy calculation were used to analyze the mercury capture active sites and investigate the mercury adsorption mechanism. The H2O2 modification and NH4Cl impregnation formed chemisorption sites of C-O, C=O and C-Cl groups. The mercury desorption energy increased from 32.2-33.0 kJ∙mol−1 of physisorption to 60.2–70.7 kJ∙mol−1 of chemisorption. This paper provides guides for future preparation of highly effective mercury removal sorbents. © 2025

关键词： Dust control

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：