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海洋内波垂向结构求解的几种数学方法 被引量:2
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作者 叶春生 蒋晶晶 《河南科学》 2009年第10期1200-1205,共6页
海洋内波垂向结构的求解有不同的数学方法.首先,简述了利用两次Sturm变换,将内波控制方程转化为Sturm-liouville标准型的主要过程.其次,给出了由一般二阶变系数常微分方程的通用变换方法,将内波控制方程转化为Sturm-liouville标准型的方... 海洋内波垂向结构的求解有不同的数学方法.首先,简述了利用两次Sturm变换,将内波控制方程转化为Sturm-liouville标准型的主要过程.其次,给出了由一般二阶变系数常微分方程的通用变换方法,将内波控制方程转化为Sturm-liouville标准型的方法.随后,通过直接差分法,给出了将内波控制方程离散化为矩阵特征值问题的一般过程.最后,详述了Thomson-Haskell方法求解内波垂向结构的过程. 展开更多
关键词 海洋内波 垂向结构 两次Sturm变换 Sturm-liouville标准型 二阶变系数常微分方程 直接差分法 Thomson-Haskell方法
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SECOND ORDER BVPS ON THE REAL LINE
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作者 Zakia Benbaziz Smal Djebali 《Annals of Differential Equations》 2015年第1期1-14,共14页
This paper is concerned with the solvability of a second-order integro-differential equation with Dirichlet boundary conditions on the real line. Under some conditions on the real parameters and coefficients, some exi... This paper is concerned with the solvability of a second-order integro-differential equation with Dirichlet boundary conditions on the real line. Under some conditions on the real parameters and coefficients, some existence results are presented. We mainly use fixed point arguments. 展开更多
关键词 second order ode interative method positive solutions whole line
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二阶变系数齐线性常微分方程的求解 被引量:6
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作者 方辉平 叶鸣 《重庆工商大学学报(自然科学版)》 2011年第1期14-17,共4页
给出了二阶变系数齐线性常微分方程一种新的求解方法.将二阶变系数齐线性常微分方程问题转化为Riccati方程来求解,讨论了二阶变系数齐线性常微分方程的通解和初值问题,得到初值问题近似解的理论基础、计算方法和误差估计.
关键词 二阶变系数齐线性常微分方程 RICCATI方程 误差估计
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An Attempt to Make Non-Elementary Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs 被引量:2
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第1期56-67,共12页
In this paper, we define an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, desc... In this paper, we define an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. The key is to start with a non-elementary integral function, differentiating and inverting, and then define a set of functions. Differentiating these functions twice give second-order nonlinear ODEs that have the defined set of functions as solutions. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ode
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Six New Sets of the Non-Elementary Jef-Family-Functions that Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2023年第4期1077-1097,共21页
In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are usi... In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. The key is to start with a non-elementary integral function, differentiating and inverting, and then define a set of three functions that belong together. Differentiating these functions twice gives second-order nonlinear ODEs that have the defined set of functions as solutions. We will study some of the second-order nonlinear ODEs, especially those that exhibit limit cycles. Using the methods described in this paper, it is possible to define many other sets of non-elementary functions that are giving solutions to some second-order nonlinear autonomous ODEs. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ode Limit Cycle
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The Extended Non-Elementary Amplitude Functions as Solutions to the Damped Pendulum Equation, the Van der Pol Equation, the Damped Duffing Equation, the Lienard Equation and the Lorenz Equations
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2023年第11期3428-3445,共18页
In this paper, we define some non-elementary amplitude functions that are giving solutions to some well-known second-order nonlinear ODEs and the Lorenz equations, but not the chaos case. We are giving the solutions a... In this paper, we define some non-elementary amplitude functions that are giving solutions to some well-known second-order nonlinear ODEs and the Lorenz equations, but not the chaos case. We are giving the solutions a name, a symbol and putting them into a group of functions and into the context of other functions. These solutions are equal to the amplitude, or upper limit of integration in a non-elementary integral that can be arbitrary. In order to define solutions to some short second-order nonlinear ODEs, we will make an extension to the general amplitude function. The only disadvantage is that the first derivative to these solutions contains an integral that disappear at the second derivation. We will also do a second extension: the two-integral amplitude function. With this extension we have the solution to a system of ODEs having a very strange behavior. Using the extended amplitude functions, we can define solutions to many short second-order nonlinear ODEs. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ode Damped Pendulum Equation Van der Pol Equation Damped Duffing Equation Lienard Equation Lorenz System
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On Two New Groups of Non-Elementary Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第3期703-713,共11页
In this paper, we define a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We will also define a group of solutions x(t) that are ... In this paper, we define a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We will also define a group of solutions x(t) that are equal to the amplitude. This is a generalized amplitude function. We are using Abel’s methods, described by Armitage and Eberlein. And finally, we define an exponential function whose exponent is the product of a complex number and the upper limit of integration in a non-elementary integral that can be arbitrary. At least three groups of non-elementary functions are special cases of this complex function. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ode
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Four New Examples of the Non-Elementary Expo-Elliptic Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第4期1304-1324,共21页
In this paper, we define four new examples of the non-elementary expo-elliptic functions. This is an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elem... In this paper, we define four new examples of the non-elementary expo-elliptic functions. This is an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. We will study some of the second-order nonlinear ODEs, especially those that exhibit limit cycles, and systems of nonlinear ODEs that these functions are giving solutions to. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ode
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