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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 {1. Mirpur University of Science and TechnologyMirpur 10250Pakistan department of {1. 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 bvp4c 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

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 {1. Henan University of TechnologyZhengzhou 450001China department of {1. 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

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 {1. Hangzhou Normal UniversityHangzhou311121China department of {1. 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

Nonlocal symmetries,soliton-cnoidal wave solution and soliton molecules to a(2+1.-dimensional modified KdV system

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Communications in Theoretical Physics 2024年第4期76卷 14-21页

作者： Jianyong Wang Bo Ren department of {1. and Physics Quzhou UniversityQuzhou 324000China department of {1. Zhejiang University of TechnologyHangzhou 310014China

A(2+1.-dimensional modified KdV(2DmKdV)system is considered from several ***,residue symmetry,a type of nonlocal symmetry,and the Bäcklund transformation are obtained via the truncated Painlevéexpansion ***,the residue symmetry is localized to a Lie point symmetry of a prolonged system,from which the finite transformation group is ***,the integrability of the 2DmKdV system is examined under the sense of consistent tanh expansion ***,explicit soliton-cnoidal wave solutions are ***,abundant patterns of soliton molecules are presented by imposing the velocity resonance condition on the multiple-soliton solution.

关键词： soliton-cnoidal wave solution nonlocal symmetry soliton molecule (2+1.-dimensional modified KdV system

SOME LIOUVILLE-TYPE THEOREMS FOR THE STATIONARY 3D MAGNETO-MICROPOLAR FLUIDS

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Acta Mathematica Scientia 2024年第6期44卷 2296-2306页

作者： Jae-Myoung KIM Seungchan KO department of {1. Education Andong National University department of {1. Inha University

In this paper,we prove some Liouville-type theorems for the stationary magnetomicropolar fluids under suitable conditions in three space *** first prove that the solutions are trivial under the assumption of certain growth conditions for the mean oscillations of the *** then we show similar results assuming that the solutions are contained in Lp（R3） with p ∈ [2,9/2).Finally,we show the same result for lower values of p ∈ [1.9/4) with the further assumption that the solutions vanish at infinity.

关键词： Liouville-type theorem stationary magneto-micropolar equations

Uniform decomposition of velocity gradient tensor

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Journal of Hydrodynamics 2024年第1期36卷 24-34页

作者： Chenxi Ma Chaoqun Liu department of {1. University of Texas at ArlingtonArlingtonTXUSA

In this paper,the principal decomposition of the velocity gradient tensor[∇v]is discussed in 3 cases based on the discriminant∆:∆0 with 3 distinct real eigen values,and∆=0 with 1.or 2 distinct real eigen *** velocity ... 详细信息

In this paper,the principal decomposition of the velocity gradient tensor[∇v]is discussed in 3 cases based on the discriminant∆:∆1.real eigen value and a pair of conjugate complex eigen values,∆>0 with 3 distinct real eigen values,and∆=0 with 1.or 2 distinct real eigen *** velocity gradient tensor can also be classified as rotation point,which can be decomposed into three parts,i.e.,rotation[R],shear[S]and stretching/compression[SC],and non-rotation point,we defined a new resistance term[L],and the tensor can be decomposed into three parts,i.e.,resistance[L],shear[S]and stretching/compression[SC].Example matric are also displayed to demonstrate the new *** of principal decomposition between 3 different cases,and between Resistance and Liutex will also be discussed.

关键词： Velocity gradient Liutex resistance fluid kinematics

Classification of Rings Associated with the Genus of Clean Graphs

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Algebra Colloquium 2024年第3期31卷 451-466页

作者： V.Ramanathan C.Selvaraj Aaqib Altaf S.Pirzada department of {1. Periyar UniversitySalem 636011Tamil NaduIndi department of {1. University of KashmirHazratbalSrinagarKashmirIndia

Let R be a ring(not necessarily commutative)with identity 1.and let CL(R)be its clean *** this paper,we investigate the genus number of the compact Riemann surface in which CL(R)can be embedded and explicitly determine all commutative rings R(up to isomorphism)such that CL(R)has genus at most *** is shown that for any Artinian ring R,CL(R)is a projective graph if and only if R is isomorphic to ***,we determine all isomorphism classes of commutative rings whose clean graphs have crosscap two.

关键词： clean graph commutative ring planar graph genus crosscap

Double stabilizations and convergence analysis of a second-order linear numerical scheme for the nonlocal Cahn-Hilliard equation

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Science China mathematics 2024年第1期67卷 187-210页

作者： Xiao Li Zhonghua Qiao Cheng Wang department of Applied {1. The Hong Kong Polytechnic UniversityHong KongChina department of {1. The University of MassachusettsNorth DartmouthMA 02747USA

In this paper,we study a second-order accurate and linear numerical scheme for the nonlocal CahnHilliard *** scheme is established by combining a modified Crank-Nicolson approximation and the Adams-Bashforth extrapolation for the temporal discretization,and by applying the Fourier spectral collocation to the spatial *** addition,two stabilization terms in different forms are added for the sake of the numerical *** conduct a complete convergence analysis by using the higher-order consistency estimate for the numerical scheme,combined with the rough error estimate and the refined *** regarding the numerical solution as a small perturbation of the exact solution,we are able to justify the discrete?^(∞)bound of the numerical solution,as a result of the rough error ***,the refined error estimate is derived to obtain the optimal rate of convergence,following the established?∞bound of the numerical ***,the energy stability is also rigorously proved with respect to a modified *** proposed scheme can be viewed as the generalization of the second-order scheme presented in an earlier work,and the energy stability estimate has greatly improved the corresponding result therein.

关键词： nonlocal Cahn-Hilliard equation second-order stabilized scheme higher-order consistency analysis rough and refined error estimate

Critical observability of partially observed discrete event systems under cyber attacks

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Science China(Information Sciences) 2024年第2期67卷 333-334页

作者： Liyun TONG Jinling LIANG Yang LIU department of {1. School of SciencesHangzhou Dianzi University School of mathematics Southeast University College of mathematics and Computer Science Zhejiang Normal University

The discrete event system(DES) is a dynamic system driven by asynchronous/sudden events and has been widely used in many critical infrastructures, such as electric transportation networks and intelligent transportatio...

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