Chaos Solitons & Fractals最新文献

{"title":"Thermosolutal magneto-convection in an anisotropic porous medium under oblique magnetic field modulation","authors":"Vivek Lodwal,&nbsp;A. Benerji Babu","doi":"10.1016/j.chaos.2025.116723","DOIUrl":"10.1016/j.chaos.2025.116723","url":null,"abstract":"<div><div>This study explores the linear and weakly nonlinear stability of thermosolutal magneto-convection in an anisotropic porous medium, subjected to a modulated oblique magnetic field comprising steady and time-periodic components. A linear stability analysis, employing the normal mode technique, examines the effects of the Chandrasekhar number, separation parameter, mechanical and thermal anisotropy parameters, Darcy number, and inclination angle on convective motion. Results reveal that an increase in the Chandrasekhar number enhances system stability by elevating the critical thermal Rayleigh number and stabilizing the system. For weakly nonlinear analysis, a power series expansion in the small amplitude of oblique magnetic field modulation is used, leading to the derivation of the nonlinear cubic Ginzburg–Landau equation via the regular asymptotic perturbation method. The Nusselt and Sherwood numbers are calculated to assess heat and mass transfer, with findings indicating that the Chandrasekhar number, magnetic Prandtl number, anisotropic parameters, and modulation frequency significantly stabilize the system. The modulation of the oblique magnetic field results in a maximum enhancement of 19% in heat transfer and 21% in mass transfer, compared to the unmodulated case. These results demonstrate the considerable impact of obliquely applied, time-varying magnetic field on the regulation of convective phenomena in porous medium.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116723"},"PeriodicalIF":5.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"q-state modified Potts model on a Cayley tree and its phase transition in antiferromagnetic region","authors":"Hasan Akın","doi":"10.1016/j.chaos.2025.116746","DOIUrl":"10.1016/j.chaos.2025.116746","url":null,"abstract":"<div><div>We introduce a modified version of the Potts model, characterized by a new Hamiltonian that assigns energy <span><math><mrow><mo>+</mo><mi>J</mi></mrow></math></span> when two nearest neighboring spins are identical, and <span><math><mrow><mo>−</mo><mi>J</mi></mrow></math></span> when interacting spins differ. This research initializes the <span><math><mi>q</mi></math></span>-state modified Potts model on a semi-infinite Cayley tree of order <span><math><mi>k</mi></math></span>, utilizing a newly proposed Hamiltonian that promotes dissimilar neighboring spins. This modification, which diverges from the traditional Potts model, addresses the influence of competing interactions pertinent to the antiferromagnetic phase transition regime. Using the cavity method, we construct limiting Gibbs measures by analyzing the associated recurrence equations. The existence of translation-invariant solutions to these relations are further explored using Preston’s approach. Our results demonstrate the existence of phase transitions exclusively in the antiferromagnetic region. Furthermore, through a stability analysis of the dynamical system, we uncover both chaotic and periodic behaviors, highlighting the rich complexity induced by the interplay of non-trivial interactions and the non-amenable geometry of the Cayley tree.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116746"},"PeriodicalIF":5.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamical modeling reveals the pivotal regulatory role of direct glutamatergic subthalamic-striatal projections in modulating basal ganglia activity during absence epilepsy","authors":"Bing Hu,&nbsp;Xingmei Wang,&nbsp;Xijian Ying,&nbsp;Jindong Zhao","doi":"10.1016/j.chaos.2025.116677","DOIUrl":"10.1016/j.chaos.2025.116677","url":null,"abstract":"<div><div>Increasing anatomical evidence suggests the existence of direct glutamatergic projections originating from the subthalamic nucleus (STN) to the striatum. However, due to the complex structure of the striatum, unraveling the impact of these subthalamostriatal projections on the functionality of the basal ganglia remains a critical and urgent task. In this paper, we conduct a comprehensive investigation into the potential role of subthalamostriatal projections in regulating absence epilepsy (AE) within a dynamic computational framework. Our findings reveal that, when the subthalamostriatal projections are disconnected within the model, the striatal output exhibits no notable regulatory influence on AE. Interestingly, the subthalamostriatal projections play a significant role in managing AE. Moreover, the directly striatum-connected pathways, which significantly influence striatal output, actively participate in the control of AE through modulation by the subthalamostriatal projections. And, the control effects of other indirectly striatum-connected basal ganglia pathways on AE are significantly influenced by the subthalamostriatal projections. Furthermore, the biologically plausible range of coupling weights on subthalamostriatal projections can be effectively estimated within the model. Crucially, our analysis indicates that striatal-related pathways regulate AE by significantly influencing the activation levels of basal ganglia nuclei. The striatal nuclei exhibit distinct high and low triggering average discharge rates, thus making it a potential effective target for clinical treatment of AE. Taking AE as an exemplar, we underscore the pivotal and non-negligible role played by subthalamostriatal projections in modulating basal ganglia functionality, potentially serving as a source of inspiration for future experimental research endeavors.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116677"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of a nonlocal dispersal multi-group epidemic model with media-related nonlinear incidence in heterogeneous environment","authors":"Yantao Luo ,&nbsp;Pengfei Liu ,&nbsp;Peng Wu ,&nbsp;Zhidong Teng","doi":"10.1016/j.chaos.2025.116713","DOIUrl":"10.1016/j.chaos.2025.116713","url":null,"abstract":"<div><div>In order to investigate the combined impact of multi-group structure and media coverage on disease transmission dynamics in heterogeneous environments, this paper develops a nonlocal diffusion multi-group SVIR epidemic model with nonlinear incidence and nonlinear contact rates driven by media coverage. Initially, we establish the well-posedness of the solution, define the threshold parameter <span><math><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>m</mi></mrow></msubsup></math></span>, and confirm the existence problem of the principal eigenvalues of the model. Subsequently, we obtain the threshold dynamics of the system, indicating that when <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>m</mi></mrow></msubsup><mo>&lt;</mo><mn>1</mn></mrow></math></span>, the disease becomes extinct, whereas when <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>m</mi></mrow></msubsup><mo>&gt;</mo><mn>1</mn></mrow></math></span>, the disease persists. Specifically, we examine a single-group degenerate diffusion model, addressing the basic reproduction number <span><math><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>s</mi></mrow></msubsup></math></span> and the presence of compact global attractors for the semi-flow. Furthermore, for <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>s</mi></mrow></msubsup><mo>&gt;</mo><mn>1</mn></mrow></math></span>, we demonstrate the existence of a unique positive steady state in the system and establish the global asymptotic stability of the endemic steady state by constructing a suitable Lyapunov functional. In the numerical simulation section, we validate the states of disease extinction and persistence by approximating the estimated basic reproduction number <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn><mo>,</mo><mi>m</mi></mrow></msub></math></span>. Our findings indicate that the disease dynamics are heavily influenced by the nonlocal diffusion kernel function. Additionally, the treatment rate plays a pivotal role in determining the ultimate outcome of the disease. While media reports may not alter the final outcome of the disease, they can effectively impede its spread and reduce the infection density.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116713"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prescribed-time bipartite synchronization for directed higher-order networks","authors":"Linlong Xu,&nbsp;Xiwei Liu","doi":"10.1016/j.chaos.2025.116733","DOIUrl":"10.1016/j.chaos.2025.116733","url":null,"abstract":"<div><div>We investigate the prescribed-time complete and bipartite synchronization problems for directed higher-order networks (DHNs). At first, a hypergraph is employed to describe the network’s topological structure, where each hyperedge connects multiple nodes. Different from many existing studies, we introduce generalized coupling matrices and a weighted coupling function, where the elements of the coupling matrices can take positive or negative values, and the nodes in the coupling function are weighted differently. To address synchronization and control problems in DHNs, we then apply the rearranging variables’ order technique to link DHNs and multiweighted networks. Next, a time-varying regulatory function is introduced, and the coupling matrices are combined from a dimensional perspective to derive the prescribed-time bipartite synchronization criteria. Finally, some numerical simulations are provided.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116733"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of communication delay and environmental uncertainties on the evolution of love model","authors":"Xiuying Guo ,&nbsp;Caiyun Huang ,&nbsp;Zikun Han ,&nbsp;Rong Wang ,&nbsp;Qiubao Wang","doi":"10.1016/j.chaos.2025.116732","DOIUrl":"10.1016/j.chaos.2025.116732","url":null,"abstract":"<div><div>This paper aims to study the effect of communication delay(the time of the first exchange in which the conflict occurred) and stochastic disturbance on human emotional relationship based on love model. It is characterized by nonlinear stochastic delay differential equations. The delay term and the random term represent the communication interval between two people and the uncertainty of the environment, respectively. Firstly, the characteristic root analysis of linear equation is carried out. Then, the system is effectively reduced by combining the central manifold theory and stochastic averaging method. On this basis, the stochastic dynamic behavior of the system is studied using <span><math><mi>τ</mi></math></span> as the bifurcation parameter. The results of theoretical analysis are verified by numerical analysis. In addition, using the communication interval of two people as a parameter, the variance graph of love between two people is obtained. As you can see, regardless of romantic style, when the communication interval exceeds the threshold, the relationship will fluctuate. So in order for the love to last long, timely communication and frequent meeting is very important. Although this paper is a simple binary relationship model, it lays a foundation for the study of more complex human emotional relationships model.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116732"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synchronization dynamics of Colpitts circuits under resistive couplings reproduced by energy constraint","authors":"Huimin Qi ,&nbsp;Fengjun Li ,&nbsp;Qingyun Wang ,&nbsp;Fuqiang Wu","doi":"10.1016/j.chaos.2025.116780","DOIUrl":"10.1016/j.chaos.2025.116780","url":null,"abstract":"<div><div>Synchronizations, one of collective behaviors, has been found in various interesting systems such as electronic devices and neuron-inspired circuits. The dynamical mechanism of nonlinear circuits remains to be an attracting topic. This paper focuses on the synchronization dynamics of Colpitts circuits. The circuit regarded as a bi-membrane neuron can exhibit complex dynamical characteristics under different parameter settings by combining theoretical analysis and numerical simulation. Based on the Lyapunov stability theory, it is proved that the drive-response circuit can achieve global exponential synchronization under unidirectional resistive and inductive couplings. A Hamilton energy function of the Colpitts circuit is deduced by employing the Helmholtz's theorem. The drive-response circuit with energy constraint is also able to show the synchronization. Finally, the synchronization mechanism of Colpitts circuit networks is investigated. It is found that the resistive coupling or the energy constraint has ability to promote the synchronization of the network. Compared to previous studies on Colpitts circuits with resistive or inductive couplings, our work uniquely integrates energy constraint to reveal a dual synchronization mechanism. This approach not only addresses the gap in understanding energy-driven synchronization in nonlinear circuits but also provides a novel framework for energy-efficient electronic system design. This study not only enriches the theoretical basis in the synchronization of nonlinear dynamics, but also provides important guidance for the design and optimization of corresponding electronic systems.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116780"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy level and coherence resonance in two memristive neurons in polarized electric field","authors":"Yixuan Chen ,&nbsp;Yitong Guo ,&nbsp;Chunni Wang ,&nbsp;Zhigang Zhu","doi":"10.1016/j.chaos.2025.116799","DOIUrl":"10.1016/j.chaos.2025.116799","url":null,"abstract":"<div><div>Applied external electric field on excitable media can modify the propagation of intracellular ions; as a result, the energy level and firing modes of the neuron are affected because of shift in membrane potential generated by the polarized field. When neurons are exposed to external electric field, the membrane potential seldom shows linear shift and physical explanation for this effect become interesting. In neural networks, each neuron suffers from the collective electric field as similar the polarized field effect. In this work, a bias voltage is applied to the branch circuit for capacitor in a simple neural circuit for estimating the polarization field effect on the cell membrane, and then energy characteristic, firing patterns and coherence resonance in its equivalent neuron model. Furthermore, a Josephson junction is incorporated into the branch circuit for replacing a nonlinear resistor with cubic term in the current-voltage relation, circuit equations and field energy are obtained, and further dynamics analysis is provided in its equivalent neuron model coupled with Josephson junction. The bias voltage for the neural circuit is mapped dimensionless parameter for the capacitive channel, and its effect on energy level and mode transition in neural activities is explored in detail. The results reveal that external electric field has important impact on the neural activities and energy levels, and a reliable neuron model is obtained to estimate the physical field effect in clear way.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116799"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phonon spectrum and gap quasi-breathers in B2 (CsCl) structure","authors":"D.U. Abdullina ,&nbsp;I.V. Kosarev ,&nbsp;R.A. Evarestov ,&nbsp;A.A. Kudreyko ,&nbsp;S.V. Dmitriev","doi":"10.1016/j.chaos.2025.116724","DOIUrl":"10.1016/j.chaos.2025.116724","url":null,"abstract":"<div><div>Discrete breathers can exist in nonlinear lattices as exact time-periodic solutions only in the absence of perturbations. In reality, long-lived spatially localized vibrational modes, called quasi-breathers (QBs), are of interest because they contribute to the macroscopic properties of crystals. Crystals with complex structure may have a gap in the phonon spectrum, and gap QBs may exist, vibrating at frequencies in the gap. Here, a binary crystal with B2 (CsCl) structure is analyzed taking into account interactions up to the fourth neighbor. The atoms of two spices have masses <span><math><msub><mrow><mi>m</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. The pairwise interatomic interactions with hard or soft cubic anharmonicity are considered. The conditions on the mass ratio <span><math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><msub><mrow><mi>m</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></math></span> and the stiffness of the interatomic bonds are derived under which the gap appears in the phonon spectrum and short- or long-lived gap QBs can exist. Short-lived QBs have the main frequency in the gap, but higher harmonics fall in the optical band of the phonon spectrum. Long-lived QBs have the main frequency and all higher harmonics outside the phonon spectrum. Examples of numerically found gap QBs are given. Our results provide a theoretical background for finding gap QBs in B2 crystals with components whose difference in atomic mass is large enough to open a gap in the phonon spectrum; examples of such crystals are given.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116724"},"PeriodicalIF":5.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation and control of grid multi-vortex attractors in memristive Hopfield neural network","authors":"Lilian Huang,&nbsp;Fangyi Chen,&nbsp;Feiyi Geng,&nbsp;Lei Zheng,&nbsp;Xihong Yu","doi":"10.1016/j.chaos.2025.116717","DOIUrl":"10.1016/j.chaos.2025.116717","url":null,"abstract":"<div><div>The grid multi-vortex attractors previously generated have typically been derived by integrating the multi-piecewise nonlinear magnetron memristor model into neural network frameworks, with limited exploration of alternative operational mechanisms. To solve this problem, a method for constructing meshed multi-vortex attractors using a memristor-based Hopfield neural network is introduced by this paper. Firstly, a trineuron-based memristor Hopfield neural network is proposed, which can generate and regulate multi-vortex attractors. At the same time, the influence of multilayer logic pulses on the dynamics of the memristor-based Hopfield neural network is focused on by this paper, and it discusses how different pulse modes regulate the attractor state of the network, thereby revealing the profound influence of pulse regulation on network behavior. In addition, the migration control behavior of the multi-vortex attractor and the grid multi-vortex attractor is studied from multiple dimensions. Ultimately, by developing an analog circuit, the numerical simulation results of the MHNN with multi-level logic pulses were replicated. The simulation results indicate the feasibility of implementing the method based on hardware.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"199 ","pages":"Article 116717"},"PeriodicalIF":5.3,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}