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Global Stability to Steady Supersonic Rayleigh Flows in One-Dimensional Duct

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Chinese Annals of mathematics,Series B 2024年第2期45卷 279-296页

作者： Fenglun WEI Jianli LIU department of mathematics Shanghai University Newtouch Center for mathematics of Shanghai University

Heat exchange plays an important role in hydrodynamical systems,which is an interesting topic in theory and *** this paper,the authors consider the global stability of steady supersonic Rayleigh flows for the one-dimensional compressible Euler equations with heat exchange,under the small perturbations of initial and boundary conditions in a finite rectilinear duct.

关键词： Compressible Euler equations Heat exchange Supersonic Rayleigh fow Steady solution Classical solution

Study of bending angle and shadow in a new Schwarzschild-like black hole affected by plasma and non-plasma mediums

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Chinese Physics C 2024年第5期48卷 309-318页

作者： Riasat Ali Tiecheng Xia Muhammad Awais Rimsha Babar department of mathematics Newtouch Center for Mathematics of Shanghai UniversityShanghai 200444China department of mathematics University of Engineering and Technology Lahore-54890Pakistan department of mathematics GC University Faisalabad Layyah CampusLayyah-31200Pakistan

In this study,we analyze the models of the deflection angle of a new Schwarzschild-like black hole(BH)and employ the optical metric of the *** achieve this,we use the Gaussian curvature of the optical metric and the Gauss-Bonnet theorem,known as the Gibbons-Werner technique,to determine the deflection ***,we examine the deflection angle in the presence of a plasma medium and the effect of the plasma medium on the deflection *** deflection angle of the BH solution in the gauged super-gravity is computed using the Keeton-Petters *** the ray-tracing technique,we investigate the shadow of the corresponding BH and analyze the plots of the deflection angle and shadow to verify the influence of the plasma and algebraic thermodynamic parameters on the deflection angle and shadow.

关键词： new Schwarzschild-like black hole Gibbons-Werner and Keeton-Petters techniques deflection angle ray-tracing approach shadow

Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4.+TiO_(2) between two stretchable rotating disks

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Applied mathematics and Mechanics(English Edition) 2024年第2期45卷 373-388页

作者： M.RAHMAN M.TURKYILMAZOGLU Z.MUSHTAQ department of mathematics Mirpur University of Science and TechnologyMirpur 10250Pakistan department of mathematics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4.+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4.+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the same volume of a *** leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity *** system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4. MATLAB *** outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower *** the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom *** ranges of various parameters taken into account are Pr=6.2,Re=2,M=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number

Evolution of light deflection and shadow from a gauge-potential-like AdS black hole under the influence of a non-magnetic plasma medium

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Communications in Theoretical Physics 2024年第9期76卷 83-94页

作者： Riasat Ali Xia Tiecheng Muhammad Awais Rimsha Babar department of mathematics Shanghai University and Newtouch Center for Mathematics of Shanghai UniversityShanghai-200444China department of mathematics University of Engineering and Technology Lahore-54890Pakistan department of mathematics GC University Faisalabad Layyah CampusLayyah-31200Pakistan

We investigate the light deflection in the weak field approximation from the accelerating charged AdS black *** this purpose,we apply the Gauss–Bonnet theorem to calculate the light deflection in the weak field area and use the Gibbons–Werner approach to analyze the optical geometry of the accelerating charged AdS black hole in the non-magnetic plasma absence/presence of a non-magnetic *** also represent the graphical behavior of the light deflection angle *** impact *** also compute the light deflection angle using Keeton and Petters approximations under the impact of accelerating charged AdS black hole ***,by using the ray-tracing approach,we determine the shadow in the nonmagnetic plasma presence and also demonstrate that graphical shadow has an impact on the gauge potential,non-magnetic plasma frequencies and charge.

关键词： accelerating charged Ad S black hole Gibbons-Werner approach deflection angle ray-tracing approach shadow

Quasi-periodically Forced Logistic Map with Weak Liouvillean Frequency

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2411-2435页

作者： Jin Hao LIANG Lin Lin FU department of Applied mathematics Nanjing Forestry University School of mathematics and Statistics Shaoguan University

Consider a class of quasi-periodically forced logistic maps■whereωis an irrational frequency and c(θ) is a specific bimodal *** prove that under weak Liouvillean condition on frequency,the strange non-chaotic attra... 详细信息

关键词： 37C60 37C70 logistic map Lyapunov exponent Quasi-periodically forced strange non-chaotic attractor weak Liouvillean frequency

The unitary subgroups of group algebras for a class of finite 2-groups with the derived subgroup of order 2

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Science China mathematics 2024年第9期67卷 1989-2018页

作者： Yulei Wang Heguo Liu department of mathematics Henan University of TechnologyZhengzhou 450001China department of mathematics Hainan UniversityHaikou 570228China

Let p be a prime and F be a finite field of characteristic *** that FG is the group algebra of the finite p-group G over the field *** V(FG)denote the group of normalized units in FG and let V_(*)(FG)denote the unitary subgroup of V(FG).If p is odd,then the order of V_(*)(FG)is|F|^((|G-1)/2).However,the case p=2 still is *** this paper,the order of V*(FG)is computed when G is a nonabelian 2-group given by a central extension of the form 1→Z_(2^(n))×Z_(2^(m))→G→Z_(2)×…×Z_(2)→1 and G'≌Z_(2),n,m≥***,a conjecture is confirmed,i.e.,the order of V_(*)(FG)can be divisible by|F|^(1/2(|G|+|Ω1(G)|)-1),where Ω_(1)(G)={g∈G|g^(2)=1}.

关键词： normalized unit unitary subgroup inner abelian p-group central extension

Centered Waves for the Two-dimensional Pseudo-Steady van der Waals Gas Satisfied Maxwell's Law Around a Sharp Corner

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Chinese Annals of mathematics,Series B 2024年第4期45卷 537-554页

作者： Shuangrong LI Wancheng SHENG department of mathematics Shanghai UniversityShanghai 200444China department of mathematics Zhejiang University of Science and TechnologyHangzhou 310023China Corresponding author.department of mathematics Newtouch Center for Mathematics of Shanghai UniversityShanghai UniversityShanghai 200444China

In this paper,the authors study the centered waves for the two-dimensional(2D for short)pseudo-steady supersonic flow with van der Waals gas satisfied Maxwell's law around a sharp *** view of the initial value of the specific volume and the properties of van der Waals gas,the centered waves at the sharp corner are constructed by *** is shown that the supersonic incoming flow turns the sharp corner by a centered simple wave or a centered simple wave with right-contact discontinuity or a composite wave(jump-fan,fan-jump or fan-jump-fan),or a combination of waves and constant ***,the critical angle of the sharp corner corresponding to the appearance of the vacuum phenomenon is obtained.

关键词： Two-dimensional Euler equations Van der Waals gas Centered simple wave Composite wave

SUMS OF DUAL TOEPLITZ PRODUCTS ON THE ORTHOGONAL COMPLEMENTS OF FOCK-SOBOLEV SPACES

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Acta Mathematica Scientia 2024年第3期44卷 810-822页

作者：陈泳 Young Joo Lee department of mathematics Hangzhou Normal UniversityHangzhou311121China department of mathematics Chonnam National UniversityGwangju61186Korea

We consider dual Toeplitz operators on the orthogonal complements of the FockSobolev spaces of all nonnegative real ***,for symbols in a certain class containing all bounded functions,we study the problem of when an operator which is finite sums of the dual Toeplitz products is compact or ***,for bounded symbols,we construct a symbol map and exhibit a short exact sequence associated with the C^(*)-algebra generated by all dual Toeplitz operators with bounded symbols.

关键词： dual Toeplitz operators Fock-Sobolev spaces symbol map

Ambarzumyan's Theorem for the Dirac Operator on Equilateral Tree Graphs

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 568-576页

作者： Dong-Jie WU Xin-Jian XU Chuan-Fu YANG department of mathematics School of Mathematics and StatisticsNanjing University of Science and TechnologyNanjing 210094China

The classical Ambarzumyan’s theorem states that if the Neumann eigenvalues of the Sturm-Liouville operator-d^(2)/dx^(2)+q with an integrable real-valued potential q on[0,π] are {n^(2):n≥0},then q=0 for almost all x∈[0,π].In this work,the classical Ambarzumyan’s theorem is extended to the Dirac operator on equilateral tree *** prove that if the spectrum of the Dirac operator on graphs coincides with the unperturbed case,then the potential is identically zero.

关键词： dirac operator quantum graph Ambarzumyan’s theorem inverse spectral problem