Mathematical Methods in the Applied Sciences最新文献

筛选
英文 中文
Normalized solutions for critical Choquard equations involving logarithmic nonlinearity in the Heisenberg group
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-30 DOI: 10.1002/mma.10528
Sihua Liang, Xuechun Zheng, Lifeng Guo
{"title":"Normalized solutions for critical Choquard equations involving logarithmic nonlinearity in the Heisenberg group","authors":"Sihua Liang,&nbsp;Xuechun Zheng,&nbsp;Lifeng Guo","doi":"10.1002/mma.10528","DOIUrl":"https://doi.org/10.1002/mma.10528","url":null,"abstract":"<p>In this paper, we consider the existence and multiplicity of normalized solutions for critical Choquard equations involving logarithmic nonlinearity in the Heisenberg group. Under suitable assumptions, combined with the truncation technique, the concentration-compactness principle, and the genus theory, we obtain the existence and multiplicity of the normalized solutions in the \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {L}&amp;amp;amp;#x0005E;p $$</annotation>\u0000 </semantics></math>-subcritical case. As far as we know, the result of the paper is completely new in the Euclidean case.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3966-3978"},"PeriodicalIF":2.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Traveling front in a diffusive predator–prey model with Beddington–DeAngelis functional response
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-30 DOI: 10.1002/mma.10508
Huimiao Dong, Xingbo Liu
{"title":"Traveling front in a diffusive predator–prey model with Beddington–DeAngelis functional response","authors":"Huimiao Dong,&nbsp;Xingbo Liu","doi":"10.1002/mma.10508","DOIUrl":"https://doi.org/10.1002/mma.10508","url":null,"abstract":"<p>In this paper, we consider a singular diffusive predator–prey model with Beddington–DeAngelis functional response, employing geometric singular perturbation theory and Bendixson's criteria. Our investigation revolves around transforming the reaction–diffusion equation into a multi-scale four-dimensional slow–fast system with two different orders of small parameters. Through once singular perturbation analysis, our focus shifts towards exploring the existence of heteroclinic orbits in a three-dimensional system. We analyze these dynamics through the perspective of the Fisher–KPP equation in two limit cases. In the first case, only the normal to the two-dimensional slow manifold is unstable. This allows for the deduction of existence of heteroclinic orbits in the three-dimensional system through investigating the dynamics on the two-dimensional slow manifold. Consequently, we obtain both monotonic traveling fronts and non-monotonic fronts with oscillatory tails. In the second case, the normal to the one-dimensional slow manifold exhibits both stable and unstable directions, then it is impossible to restrict the dynamics of the three-dimensional system entirely to the slow manifold. Instead, we integrate the slow orbits of the reduced system with the fast orbits of the layer system to construct a singular heteroclinic orbit. According to Fenichel's theorem, we discover the existence of exact heteroclinic orbits of three-dimensional system and derive the monotonic traveling fronts under weaker parameter conditions. Additionally, we also discuss the nonexistence of traveling fronts. Finally, we demonstrate our theoretical results with numerical simulations.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3682-3711"},"PeriodicalIF":2.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Mathematical analysis and optimal control of age-structured social interaction model with law enforcement
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-29 DOI: 10.1002/mma.10509
Manoj Kumar, Soniya Dhama, Faez A. Alqarni, Syed Abbas, Khaled A. Aldwoah
{"title":"Mathematical analysis and optimal control of age-structured social interaction model with law enforcement","authors":"Manoj Kumar,&nbsp;Soniya Dhama,&nbsp;Faez A. Alqarni,&nbsp;Syed Abbas,&nbsp;Khaled A. Aldwoah","doi":"10.1002/mma.10509","DOIUrl":"https://doi.org/10.1002/mma.10509","url":null,"abstract":"<p>Optimal use of available resources is one of the major issues in many situations. Apart from this, age is also an important factor in modeling social interaction in a society. In this article, we consider an age-dependent social interaction model and study the stability and optimal control. Law enforcement is an important factor in controlling crime, and the deployment of police to enforce it is important. Now cost is a major issue, so optimal deployment is very important to study. Stability results are derived in terms of threshold parameters. Basic reproduction number is calculated for stability analysis. Using the adjoint system, the form of the law enforcement factor is obtained in terms of state space variables. We see that the cost functional increases with the increase in the population density of criminal population. Numerical results are also added to visually illustrate our theoretical results.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3712-3725"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On a class of generalized capillarity system involving fractional ψ#x02010;Hilfer derivative with p(·)-Laplacian operator
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-29 DOI: 10.1002/mma.10495
Elhoussain Arhrrabi, Hamza El-Houari
{"title":"On a class of generalized capillarity system involving fractional ψ#x02010;Hilfer derivative with p(·)-Laplacian operator","authors":"Elhoussain Arhrrabi,&nbsp;Hamza El-Houari","doi":"10.1002/mma.10495","DOIUrl":"https://doi.org/10.1002/mma.10495","url":null,"abstract":"<p>This research delves into a comprehensive investigation of a class of \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ψ</mi>\u0000 </mrow>\u0000 <annotation>$$ psi $$</annotation>\u0000 </semantics></math>-Hilfer generalized fractional nonlinear differential system originated from a capillarity phenomena with Dirichlet boundary conditions, focusing on issues of existence and multiplicity of nonnegative solutions. The nonlinearity of the problem, in general, does not satisfy the Ambrosetti–Rabinowitz type condition. We use minimization arguments of Nehari manifold together with variational approach to show the existence and multiplicity of positive solutions of our problem with respect to the parameter \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ξ</mi>\u0000 </mrow>\u0000 <annotation>$$ xi $$</annotation>\u0000 </semantics></math> in appropriate fractional \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ψ</mi>\u0000 </mrow>\u0000 <annotation>$$ psi $$</annotation>\u0000 </semantics></math>-Hilfer spaces. Our main result is novel, and its investigation will enhance the scope of the literature on coupled systems of fractional \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ψ</mi>\u0000 </mrow>\u0000 <annotation>$$ psi $$</annotation>\u0000 </semantics></math>-Hilfer generalized capillary phenomena.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3448-3470"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Traveling waves reflecting various processes represented by reaction–diffusion equations
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-29 DOI: 10.1002/mma.10493
Murat Sari, Asif Yokus, Serbay Duran, Hulya Durur
{"title":"Traveling waves reflecting various processes represented by reaction–diffusion equations","authors":"Murat Sari,&nbsp;Asif Yokus,&nbsp;Serbay Duran,&nbsp;Hulya Durur","doi":"10.1002/mma.10493","DOIUrl":"https://doi.org/10.1002/mma.10493","url":null,"abstract":"<p>The aim of this paper is to discover analytically the interactional responses of populations in a dynamic region where the reaction–diffusion process with forcing effects takes place through traveling wave solutions. An expansion method is considered here to properly capture the responses for the first time. In order to profoundly analyze the physical and mathematical discussions, some illustrative behavioral results are exhibited for various values of physical parameters. Especially for the different values of diffusion coefficients in the model under consideration, their effects on the behavior of the solitary wave are discussed and observationally supported by considering various illustrations. It is also seen that the solutions representing the diffusion seen to be in the form of the behavior of hexagonal Turing patterns in different time periods. The application of this study in mathematical biology is to analyze the relationship between the population density of certain species in any local region and the specific population density with invasion characteristics. In addition, the formation of the extinction vortex of the invading population, depending on the characteristics of the solutions presented, is also descriptively discussed.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3414-3433"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On a Dirichlet problem related to anisotropic fluid flow in bidisperse porous media
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-29 DOI: 10.1002/mma.10506
Andrei Gasparovici
{"title":"On a Dirichlet problem related to anisotropic fluid flow in bidisperse porous media","authors":"Andrei Gasparovici","doi":"10.1002/mma.10506","DOIUrl":"https://doi.org/10.1002/mma.10506","url":null,"abstract":"<p>This paper is concerned with the study of a Dirichlet boundary value problem for a system of two coupled anisotropic Darcy–Forchheimer–Brinkman equations on a bounded Lipschitz domain in \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mrow>\u0000 <mi>ℝ</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>n</mi>\u0000 </mrow>\u0000 </msup>\u0000 <mo>(</mo>\u0000 <mi>n</mi>\u0000 <mo>=</mo>\u0000 <mn>2,3</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$$ {mathrm{mathbb{R}}}&amp;amp;amp;#x0005E;nleft(n&amp;amp;amp;#x0003D;2,3right) $$</annotation>\u0000 </semantics></math>. Using variational methods and fixed point techniques, we obtain a well-posedness result in \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {L}&amp;amp;amp;#x0005E;2 $$</annotation>\u0000 </semantics></math>-based Sobolev spaces for sufficiently small data. As an application, we investigate numerically the lid-driven flow problem in a square cavity saturated with a bidisperse porous medium and analyze the effect of various physical parameters on the fluid motion.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3652-3669"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mma.10506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Partially extended oscillation and nonoscillation theorems for half-linear Hill-type differential equations with periodic damping
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-29 DOI: 10.1002/mma.10511
Kazuki Ishibashi
{"title":"Partially extended oscillation and nonoscillation theorems for half-linear Hill-type differential equations with periodic damping","authors":"Kazuki Ishibashi","doi":"10.1002/mma.10511","DOIUrl":"https://doi.org/10.1002/mma.10511","url":null,"abstract":"<p>This study addressed the oscillation problems of half-linear differential equations with periodic damping. The solution space of any linear equation is homogeneous and additive. Generally, by contrast, the solution space of half-linear differential equations is homogeneous but not additive. Numerous oscillation and nonoscillation theorems have been devised for half-linear differential equations featuring periodic functions as coefficients. However, in certain cases, such as applying Mathieu-type differential equations to control engineering, which is a typical example of the Hill equation, some oscillation theorems cannot be applied. In this study, we established oscillation and nonoscillation theorems for half-linear Hill-type differential equations with periodic damping. To prove the results, we used the Riccati technique and the composite function method, which focuses on the composite function of the indefinite integral of the coefficients of the target equation and an appropriate multivalued continuously differentiable function. Furthermore, we discuss the special case of the oscillation constant of a damped half-linear Mathieu equation.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3748-3758"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hermite solution for a new fractional inverse differential problem
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-28 DOI: 10.1002/mma.10516
Mohammed Elamine Beroudj, Abdelaziz Mennouni, Carlo Cattani
{"title":"Hermite solution for a new fractional inverse differential problem","authors":"Mohammed Elamine Beroudj,&nbsp;Abdelaziz Mennouni,&nbsp;Carlo Cattani","doi":"10.1002/mma.10516","DOIUrl":"https://doi.org/10.1002/mma.10516","url":null,"abstract":"<p>Mathematics, mathematical modeling of real systems, and mathematical and computer methodologies aimed at the qualitative and quantitative study of real physical systems interact in a nontrivial way. This work aims to examine a new class of inverse problems for a fractional partial differential equation with order fractional \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>0</mn>\u0000 <mo>&lt;</mo>\u0000 <mi>ρ</mi>\u0000 <mo>≤</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$$ 0&amp;amp;lt;rho le 1 $$</annotation>\u0000 </semantics></math>, which leads to the spectral problem involving Hermite's differential equation. We introduce proven theorems on the existence and uniqueness of solutions to the current problem. We obtain solutions in the form of series expansion using the Hermite orthogonal basis. Finally, we discuss the convergence analysis of the obtained solutions.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3811-3824"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mma.10516","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Global-in-time well-posedness of solutions for the 2D hyperbolic Prandtl equations in an analytic framework
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-28 DOI: 10.1002/mma.10523
Xiaolei Dong
{"title":"Global-in-time well-posedness of solutions for the 2D hyperbolic Prandtl equations in an analytic framework","authors":"Xiaolei Dong","doi":"10.1002/mma.10523","DOIUrl":"https://doi.org/10.1002/mma.10523","url":null,"abstract":"<p>In this paper, we consider the 2D hyperbolic Prandtl equations on the half plane. Firstly, we obtain the global existence of solutions by using the classical energy methods in an analytic framework. Then, we prove the uniqueness of solutions. Besides, we also obtain a time exponential decay in analytic regularity norm of the solutions for any time \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>t</mi>\u0000 <mo>≥</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$$ tge 0 $$</annotation>\u0000 </semantics></math>.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3895-3906"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Bifurcation, quasi-periodic, chaotic pattern, and soliton solutions for a time-fractional dynamical system of ion sound and Langmuir waves
IF 2.1 3区 数学
Mathematical Methods in the Applied Sciences Pub Date : 2024-09-28 DOI: 10.1002/mma.10517
Adel Elmandouh
{"title":"Bifurcation, quasi-periodic, chaotic pattern, and soliton solutions for a time-fractional dynamical system of ion sound and Langmuir waves","authors":"Adel Elmandouh","doi":"10.1002/mma.10517","DOIUrl":"https://doi.org/10.1002/mma.10517","url":null,"abstract":"<p>This paper strives to investigate the time fractional system that characterizes the ion sound wave influenced by the ponderomotive force induced by a high-frequency field, as well as the Langmuir wave in plasma. Initially, based on the qualitative theory for planar integrable systems, four-phase portraits are found in the \u0000<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>u</mi>\u0000 <mo>,</mo>\u0000 <mi>y</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$$ left(u,yright) $$</annotation>\u0000 </semantics></math> phase plane under certain conditions on the physical parameters. These conditions are used to prove analytically the existence of solitary, kink (anti-kink), periodic, super-periodic, and unbounded wave solutions. The correspondence between the energy levels, phase orbits, and consequently the type of the solution is announced. We derived the bounded wave solutions associated with the phase orbits, which are shown to be consistent with the qualitative analysis of the types of solutions. Moreover, we studied the consistency between the obtained solutions by investigating the degeneracy of the solutions through the transmission between the phase orbits, or equivalently, through the dependence on the initial conditions. With the presence of perturbed periodic terms, the quasi-periodic behavior and chaotic patterns are investigated.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"48 3","pages":"3825-3841"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信