In this paper, the travelling wave solutions for the generalized Burgers-Huxley equation with nonlinear terms of any order are studied. By using the first integral method, which is based on the divisor theorem, some e...In this paper, the travelling wave solutions for the generalized Burgers-Huxley equation with nonlinear terms of any order are studied. By using the first integral method, which is based on the divisor theorem, some exact explicit travelling solitary wave solutions for the above equation are obtained. As a result, some minor errors and some known results in the previousl literature are clarified and improved.展开更多
In this paper, based on a new more general ansitz, a new algebraic method, named generalized Riccati equation rational expansion method, is devised for constructing travelling wave solutions for nonlinear evolution eq...In this paper, based on a new more general ansitz, a new algebraic method, named generalized Riccati equation rational expansion method, is devised for constructing travelling wave solutions for nonlinear evolution equations with nonlinear terms of any order. Compared with most existing tanh methods for finding travelling wave solutions, the proposed method not only recovers the results by most known algebraic methods, but also provides new and more general solutions. We choose the generalized Burgers-Fisher equation with nonlinear terms of any order to illustrate our method. As a result, we obtain several new kinds of exact solutions for the equation. This approach can also be applied to other nonlinear evolution equations with nonlinear terms of any order.展开更多
SUN Da-peng BAO Wei-bin, WU Hao and LI Yu-cheng （ In this paper the 0-1 combined BEM is adopted to subdivide the computational domain boundary, and to discretize the Green＇s integral expression based on Laplace equ...SUN Da-peng BAO Wei-bin, WU Hao and LI Yu-cheng （ In this paper the 0-1 combined BEM is adopted to subdivide the computational domain boundary, and to discretize the Green＇s integral expression based on Laplace equation. The FEM is used to subdivide the wave surface and deduce the surface equation which satisfies the nonlinear boundary conditions on the surface. The equations with potential function and wave surface height as an unknown quantity by application of Taylor expansion approach can be solved by iteration within the time step. In m-time iteration within the computational process of time step （n-1）At to nat, the results of the previous iteration are taken as the initial value of the two-order unknown terms in the present iteration. Thus, an improved tracking mode of nonlinear wave surface is estabIished, and numerical results of wave tank test indicate that this mode is improved obviously and is more precise than the previous numerical model which ignored the two-order unknown terms of wave surface location and velocity potential function in comparison with the theoretical values.展开更多
We study a class of nonlinear elliptic equations with nonstandard growth condition.The main feature is that two lower order terms,a non-coercive divergence term divΦ(x,u)and a gradient term H(x,u,▽u)with no growth r...We study a class of nonlinear elliptic equations with nonstandard growth condition.The main feature is that two lower order terms,a non-coercive divergence term divΦ(x,u)and a gradient term H(x,u,▽u)with no growth restriction on u,appear simultaneously in the variable exponents setting.These characteristics prevent us from directly obtaining the existence of solutions by employing the classical theory on existence results.By choosing some appropriate test functions in the perturbed problem,some a priori estimates are obtained under the variable exponent framework.Based on these estimates,we prove the almost everywhere convergence of the gradient sequence{▽u^(ε)}_(ε),which helps to pass to the limit to find a weak solution.展开更多
In the setting of variable exponent,an existence result to a class of parabolic equations with zero order term is proved.The proof of existence relies essentially on selecting some suitable test functions based upon t...In the setting of variable exponent,an existence result to a class of parabolic equations with zero order term is proved.The proof of existence relies essentially on selecting some suitable test functions based upon the integrability of the source term and the zero order term simultaneously.By virtue of a priori estimates and some limit analyses,the weak limit of the nonlinear principal term is identified via the Young measures method.展开更多
We consider a class of nonlinear parabolic equations whose prototype is ut-Δu=b(x,t)·■+γ|■u|^(2)-divF(x,t)+f(x,t),(x,t)∈ΩT,u(x,t)=∈ГT,u(x,0)=u0(x),x∈Ω where the functions|b(x,t)|^(2),|F(x,t)|^(2),f(x,t)...We consider a class of nonlinear parabolic equations whose prototype is ut-Δu=b(x,t)·■+γ|■u|^(2)-divF(x,t)+f(x,t),(x,t)∈ΩT,u(x,t)=∈ГT,u(x,0)=u0(x),x∈Ω where the functions|b(x,t)|^(2),|F(x,t)|^(2),f(x,t)lie in the space Lr(0,T;Lq(Ω)),γis a positive constant.The purpose of this paper is to prove,under suitable assumptions on the integrability of the space Lr(0,T;Lq(Ω))for the source terms and the coefficient of the gradient term,a priori L^(∞)estimate and the existence of bounded solutions.The methods consist of constructing a family of perturbation problems by regularization,Stampacchia’s iterative technique fulfilled by an appropriate nonlinear test function and compactness argument for the limit process.展开更多
By using the theory of compensated compactness,we prove that there exists a sequence {uδε} converges nearly everywhere to the solution of the initial-value problem of generalized KdV equation with high order perturb...By using the theory of compensated compactness,we prove that there exists a sequence {uδε} converges nearly everywhere to the solution of the initial-value problem of generalized KdV equation with high order perturbation terms,namely we prove the existence of the weak solution.展开更多
The higher order asymptotic fields at the tip of a sharp V-notchin a power-hardening material for plane strain problem of Mode I arederived. The order hierarchy in powers of r for various hardeningexponents n and notc...The higher order asymptotic fields at the tip of a sharp V-notchin a power-hardening material for plane strain problem of Mode I arederived. The order hierarchy in powers of r for various hardeningexponents n and notch angles β is obtained. The angulardistributions of stress for several cases are plotted. Theself-similarity behavior between the higher order terms is noticed.It is found that the terms with higher Order can be neglected for theV-notch angle β>45°.展开更多
Polynomial composition is the operation of replacing variables in a polynomial with other polynomials. λ-Grgbner basis is an especial Grobner basis. The main problem in the paper is： when does composition commute wi...Polynomial composition is the operation of replacing variables in a polynomial with other polynomials. λ-Grgbner basis is an especial Grobner basis. The main problem in the paper is： when does composition commute with λ-Grobner basis computation？ We shall answer better the above question. This has a natural application in the computation of λ-Grobner bases.展开更多
Abstract. In this paper we contribute with one main result to the interesting probleminitiated by Hong(1998) on the behaviour of Groebner bases under composition of polyno-mials. Polynomial composition is the operatio...Abstract. In this paper we contribute with one main result to the interesting probleminitiated by Hong(1998) on the behaviour of Groebner bases under composition of polyno-mials. Polynomial composition is the operation of replacing the variables of a polynomialwith other polynomials. The main question of this paper is: Does there exist a decisionprocedure that will determine whether a given composition is comPatible with a given termordering? If so, find one. We will give a better answer.展开更多
Composition is the operation of replacing variables in a polynomial with other polynomials. The main question in this paper is: when does composition commute with universal Groebner basis computation? We prove that th...Composition is the operation of replacing variables in a polynomial with other polynomials. The main question in this paper is: when does composition commute with universal Groebner basis computation? We prove that this happens iff the composition is single variable. This has a natural application in the computation of universal Groebner bases of composed polynomials.展开更多
A frozen orbit is beneficial for observation owing to its stationary apsidal line.The traditional gravitational field model of frozen orbits only considers the main zonal harmonic terms J_(2) and limited high-order te...A frozen orbit is beneficial for observation owing to its stationary apsidal line.The traditional gravitational field model of frozen orbits only considers the main zonal harmonic terms J_(2) and limited high-order terms,which cannot meet the stringent demands of all missions.In this study,the gravitational field is expanded to J_(15) terms and the Hamiltonian canonical form described by the Delaunay variables is used.The zonal harmonic coefficients of the Earth are chosen as the sample.Short-periodic terms are eliminated based on the Hori-Lie transformation.An algorithm is developed to solve all equilibrium points of the Hamiltonian function.A stable frozen orbit with an argument of perigee that equals neither 90°nor 270°is first reported in this paper.The local stability and topology of the equilibrium points are obtained from their eigenvalues.The bifurcations of the equilibrium points are presented by drawing their global long-term evolution of frozen orbits and their orbital periods.The relationship between the terms of the gravitational field and number of frozen points is addressed to explain why only limited frozen orbits are found in the low-order term case.The analytical results can be applied to other Earth-like planets and asteroids.展开更多
In overcoming the drawbacks of traditional interval perturbation method due to the unpredictable effect of ignoring higher order terms,a modified parameter perturbation method is presented to predict the eigenvalue in...In overcoming the drawbacks of traditional interval perturbation method due to the unpredictable effect of ignoring higher order terms,a modified parameter perturbation method is presented to predict the eigenvalue intervals of the uncertain structures with interval parameters.In the proposed method,interval variables are used to quantitatively describe all the uncertain parameters.Different order perturbations in both eigenvalues and eigenvectors are fully considered.By retaining higher order terms,the original dynamic eigenvalue equations are transformed into interval linear equations based on the orthogonality and regularization conditions of eigenvectors.The eigenvalue ranges and corresponding eigenvectors can be approximately predicted by the parameter combinatorial approach.Compared with the Monte Carlo method,two numerical examples are given to demonstrate the accuracy and efficiency of the proposed algorithm to solve both the real eigenvalue problem and complex eigenvalue problem.展开更多
Pan and Wang presented a method for computing uniform GrSbner bases for certain ide- als generated by polynomials with parametric exponents in 2006, and two criteria were proposed to determine if a uniform GrSbner bas...Pan and Wang presented a method for computing uniform GrSbner bases for certain ide- als generated by polynomials with parametric exponents in 2006, and two criteria were proposed to determine if a uniform GrSbner basis can be obtained. This paper gives a new algorithmic approach for computing tile uniform GrSbner basis such that Pan and Wang＇s method could be concluded as a special case. The authors use the method of reduced term order under ring homomorphisnl to get the reduced uniform GrSbner basis. Also the authors point and correct a mistake in Pan and Wang＇s method. The result is a generalization of approach of Pan and Wang and one could compute the uniform GrSbner basis more efficiently by the new approach.展开更多
Insa and Pauer presented a basic theory of Grbner bases for differential operators with coefficients in a commutative ring and an improved version of this result was given by Ma et al.In this paper,we present an algor...Insa and Pauer presented a basic theory of Grbner bases for differential operators with coefficients in a commutative ring and an improved version of this result was given by Ma et al.In this paper,we present an algorithmic approach for computing Grbner bases in difference-differential modules with coefficients in a commutative ring.We combine the generalized term order method of Zhou and Winkler with SPoly method of Insa and Pauer to deal with the problem.Our result is a generalization of theories of Insa and Pauer,Ma et al.,Zhou and Winkler and includes them as special cases.展开更多
基金supported by the Research Foundation of Education Bureau of Hubei Province,China (Grant No Z200612001)the Natural Science Foundation of Yangtze University (Grant No 20061222)
文摘In this paper, the travelling wave solutions for the generalized Burgers-Huxley equation with nonlinear terms of any order are studied. By using the first integral method, which is based on the divisor theorem, some exact explicit travelling solitary wave solutions for the above equation are obtained. As a result, some minor errors and some known results in the previousl literature are clarified and improved.
基金The project partially supported by the State Key Basic Research Program of China under Grant No. 2004CB318000
文摘In this paper, based on a new more general ansitz, a new algebraic method, named generalized Riccati equation rational expansion method, is devised for constructing travelling wave solutions for nonlinear evolution equations with nonlinear terms of any order. Compared with most existing tanh methods for finding travelling wave solutions, the proposed method not only recovers the results by most known algebraic methods, but also provides new and more general solutions. We choose the generalized Burgers-Fisher equation with nonlinear terms of any order to illustrate our method. As a result, we obtain several new kinds of exact solutions for the equation. This approach can also be applied to other nonlinear evolution equations with nonlinear terms of any order.
基金supported by the National Natural Science Foundation of China (Grant No. 50921001)
文摘SUN Da-peng BAO Wei-bin, WU Hao and LI Yu-cheng （ In this paper the 0-1 combined BEM is adopted to subdivide the computational domain boundary, and to discretize the Green＇s integral expression based on Laplace equation. The FEM is used to subdivide the wave surface and deduce the surface equation which satisfies the nonlinear boundary conditions on the surface. The equations with potential function and wave surface height as an unknown quantity by application of Taylor expansion approach can be solved by iteration within the time step. In m-time iteration within the computational process of time step （n-1）At to nat, the results of the previous iteration are taken as the initial value of the two-order unknown terms in the present iteration. Thus, an improved tracking mode of nonlinear wave surface is estabIished, and numerical results of wave tank test indicate that this mode is improved obviously and is more precise than the previous numerical model which ignored the two-order unknown terms of wave surface location and velocity potential function in comparison with the theoretical values.
基金Supported by the National Natural Science Foundation of China(Grant No.11901131)the University-Level Research Fund Project in Guizhou University of Finance and Economics(Grant No.2022KYYB01)。
文摘We study a class of nonlinear elliptic equations with nonstandard growth condition.The main feature is that two lower order terms,a non-coercive divergence term divΦ(x,u)and a gradient term H(x,u,▽u)with no growth restriction on u,appear simultaneously in the variable exponents setting.These characteristics prevent us from directly obtaining the existence of solutions by employing the classical theory on existence results.By choosing some appropriate test functions in the perturbed problem,some a priori estimates are obtained under the variable exponent framework.Based on these estimates,we prove the almost everywhere convergence of the gradient sequence{▽u^(ε)}_(ε),which helps to pass to the limit to find a weak solution.
基金Supported by the National Natural Science Foundation of China(Grant No.11901131)the University-Level Research Fund Project in Guizhou University of Finance and Economics(Grant No.2022KYYB01)。
文摘In the setting of variable exponent,an existence result to a class of parabolic equations with zero order term is proved.The proof of existence relies essentially on selecting some suitable test functions based upon the integrability of the source term and the zero order term simultaneously.By virtue of a priori estimates and some limit analyses,the weak limit of the nonlinear principal term is identified via the Young measures method.
基金Supported by the National Natural Science Foundation of China(Grant No.11901131)the University-Level Research Fund Project in Guizhou University of Finance and Economics(Grant No.2019XYB08)。
文摘We consider a class of nonlinear parabolic equations whose prototype is ut-Δu=b(x,t)·■+γ|■u|^(2)-divF(x,t)+f(x,t),(x,t)∈ΩT,u(x,t)=∈ГT,u(x,0)=u0(x),x∈Ω where the functions|b(x,t)|^(2),|F(x,t)|^(2),f(x,t)lie in the space Lr(0,T;Lq(Ω)),γis a positive constant.The purpose of this paper is to prove,under suitable assumptions on the integrability of the space Lr(0,T;Lq(Ω))for the source terms and the coefficient of the gradient term,a priori L^(∞)estimate and the existence of bounded solutions.The methods consist of constructing a family of perturbation problems by regularization,Stampacchia’s iterative technique fulfilled by an appropriate nonlinear test function and compactness argument for the limit process.
基金Supported by the Innovation Talents of Science and Technology of Henan University(2009-HASTIT-007)Supported by the Natural Science Program of Department of Education(2011A110006)
文摘By using the theory of compensated compactness,we prove that there exists a sequence {uδε} converges nearly everywhere to the solution of the initial-value problem of generalized KdV equation with high order perturbation terms,namely we prove the existence of the weak solution.
基金the National Natural Science Foundation of China (Nos.10132010 and 10072033).
文摘The higher order asymptotic fields at the tip of a sharp V-notchin a power-hardening material for plane strain problem of Mode I arederived. The order hierarchy in powers of r for various hardeningexponents n and notch angles β is obtained. The angulardistributions of stress for several cases are plotted. Theself-similarity behavior between the higher order terms is noticed.It is found that the terms with higher Order can be neglected for theV-notch angle β>45°.
基金The research is supported by the National Natural Science Foundation of China under Grant No. 10771058, Hunan Provincial Natural Science Foundation of China under Grant No. o6jj20053, and Scientific Research Fund of Hunan Provincial Education Department under Grant No. 06A017.
文摘Polynomial composition is the operation of replacing variables in a polynomial with other polynomials. λ-Grgbner basis is an especial Grobner basis. The main problem in the paper is： when does composition commute with λ-Grobner basis computation？ We shall answer better the above question. This has a natural application in the computation of λ-Grobner bases.
基金the Foundation of Nature Science of Hunan Province(98JJY2052)
文摘Abstract. In this paper we contribute with one main result to the interesting probleminitiated by Hong(1998) on the behaviour of Groebner bases under composition of polyno-mials. Polynomial composition is the operation of replacing the variables of a polynomialwith other polynomials. The main question of this paper is: Does there exist a decisionprocedure that will determine whether a given composition is comPatible with a given termordering? If so, find one. We will give a better answer.
基金This paper is aided financially by Youth Item in the Education Department of Hunan Province(03B047) Natural Science Fund in China( 10371036).
文摘Composition is the operation of replacing variables in a polynomial with other polynomials. The main question in this paper is: when does composition commute with universal Groebner basis computation? We prove that this happens iff the composition is single variable. This has a natural application in the computation of universal Groebner bases of composed polynomials.
基金supported in part by the National Natural Science Foundation of China(Nos.11772024 and 11432001)Qian Xuesen Youth Innovation Foundation of China Aerospace Science and Technology Corporation.
文摘A frozen orbit is beneficial for observation owing to its stationary apsidal line.The traditional gravitational field model of frozen orbits only considers the main zonal harmonic terms J_(2) and limited high-order terms,which cannot meet the stringent demands of all missions.In this study,the gravitational field is expanded to J_(15) terms and the Hamiltonian canonical form described by the Delaunay variables is used.The zonal harmonic coefficients of the Earth are chosen as the sample.Short-periodic terms are eliminated based on the Hori-Lie transformation.An algorithm is developed to solve all equilibrium points of the Hamiltonian function.A stable frozen orbit with an argument of perigee that equals neither 90°nor 270°is first reported in this paper.The local stability and topology of the equilibrium points are obtained from their eigenvalues.The bifurcations of the equilibrium points are presented by drawing their global long-term evolution of frozen orbits and their orbital periods.The relationship between the terms of the gravitational field and number of frozen points is addressed to explain why only limited frozen orbits are found in the low-order term case.The analytical results can be applied to other Earth-like planets and asteroids.
基金supported by the National Natural Science Foundation of China(Grant No.90816024)Defense Industrial Technology Development Program(Grant Nos.A2120110001 and B2120110011)111 Project(Grant No.B07009)
文摘In overcoming the drawbacks of traditional interval perturbation method due to the unpredictable effect of ignoring higher order terms,a modified parameter perturbation method is presented to predict the eigenvalue intervals of the uncertain structures with interval parameters.In the proposed method,interval variables are used to quantitatively describe all the uncertain parameters.Different order perturbations in both eigenvalues and eigenvectors are fully considered.By retaining higher order terms,the original dynamic eigenvalue equations are transformed into interval linear equations based on the orthogonality and regularization conditions of eigenvectors.The eigenvalue ranges and corresponding eigenvectors can be approximately predicted by the parameter combinatorial approach.Compared with the Monte Carlo method,two numerical examples are given to demonstrate the accuracy and efficiency of the proposed algorithm to solve both the real eigenvalue problem and complex eigenvalue problem.
基金supported by the National Natural Science Foundation of China under Grant No.11271040Science and Technology Foundation of Gui Zhou Province LKM[2013]16
文摘Pan and Wang presented a method for computing uniform GrSbner bases for certain ide- als generated by polynomials with parametric exponents in 2006, and two criteria were proposed to determine if a uniform GrSbner basis can be obtained. This paper gives a new algorithmic approach for computing tile uniform GrSbner basis such that Pan and Wang＇s method could be concluded as a special case. The authors use the method of reduced term order under ring homomorphisnl to get the reduced uniform GrSbner basis. Also the authors point and correct a mistake in Pan and Wang＇s method. The result is a generalization of approach of Pan and Wang and one could compute the uniform GrSbner basis more efficiently by the new approach.
基金supported by National Natural Science Foundation of China (Grant No.10871017)Natural Science Foundation of Beijing (Grant No. 1102026)
文摘Insa and Pauer presented a basic theory of Grbner bases for differential operators with coefficients in a commutative ring and an improved version of this result was given by Ma et al.In this paper,we present an algorithmic approach for computing Grbner bases in difference-differential modules with coefficients in a commutative ring.We combine the generalized term order method of Zhou and Winkler with SPoly method of Insa and Pauer to deal with the problem.Our result is a generalization of theories of Insa and Pauer,Ma et al.,Zhou and Winkler and includes them as special cases.
