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REDUCTIVE PERTURBATION METHOD OF SUPER KdV EQUATIONS
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作者 吕克璞 孙建安 +1 位作者 段文山 赵金保 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第7期846-850,共5页
By using reductive perturbation method, super KdV equations are changed into ordinary KdV equations, small amplitude perturbation solutions are obtained.
关键词 super KdV equation reductive perturbation method KdV equation
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Precise integration method for solving singular perturbation problems 被引量:1
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作者 富明慧 张文志 S.V.SHESHENIN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第11期1463-1472,共10页
This paper presents a precise method for solving singularly perturbed boundary-value problems with the boundary layer at one end. The method divides the interval evenly and gives a set of algebraic equations in a matr... This paper presents a precise method for solving singularly perturbed boundary-value problems with the boundary layer at one end. The method divides the interval evenly and gives a set of algebraic equations in a matrix form by the precise integration relationship of each segment. Substituting the boundary conditions into the algebraic equations, the coefficient matrix can be transformed to the block tridiagonal matrix. Considering the nature of the problem, an efficient reduction method is given for solving singular perturbation problems. Since the precise integration relationship introduces no discrete error in the discrete process, the present method has high precision. Numerical examples show the validity of the present method. 展开更多
关键词 singular perturbation problem first-order ordinary differential equation two-point boundary-value problem precise integration method reduction method
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Approximate direct reduction method:infinite series reductions to the perturbed mKdV equation
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作者 焦小玉 楼森岳 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第9期3611-3615,共5页
The approximate direct reduction method is applied to the perturbed mKdV equation with weak fourth order dispersion and weak dissipation. The similarity reduction solutions of different orders conform to formal cohere... The approximate direct reduction method is applied to the perturbed mKdV equation with weak fourth order dispersion and weak dissipation. The similarity reduction solutions of different orders conform to formal coherence, accounting for infinite series reduction solutions to the original equation and general formulas of similarity reduction equations. Painleve Ⅱ type equations, hyperbolic secant and Jacobi elliptic function solutions are obtained for zeroorder similarity reduction equations. Higher order similarity reduction equations are linear variable coefficient ordinary differential equations. 展开更多
关键词 perturbed mKdV equation approximate direct reduction method series reduction solutions
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THE PERTURBATION PROBLEM OF AN ELLIPTIC SYSTEM WITH SOBOLEV CRITICAL GROWTH
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作者 Qi LI 《Acta Mathematica Scientia》 SCIE CSCD 2020年第5期1391-1404,共14页
In this paper,we study the following perturbation problem with Sobolev critical exponen t:{-Δu=(1+εK(x))u^2*-1+α/2*u^a-1v^3+εh(x)u^pP,x∈R^N,-Δu=(1+εQ(x))v^2*-1+β/2*u^B-1+εl(x)u^q,x∈R^N,u>0,v>0,x∈R^N w... In this paper,we study the following perturbation problem with Sobolev critical exponen t:{-Δu=(1+εK(x))u^2*-1+α/2*u^a-1v^3+εh(x)u^pP,x∈R^N,-Δu=(1+εQ(x))v^2*-1+β/2*u^B-1+εl(x)u^q,x∈R^N,u>0,v>0,x∈R^N where 0<p,q<1,α+β=2*:=2N/N-2,α,β≥3,4.Using a perturbation argument and a finite dimensional reduc tion met hod,we get the exis tence of positive solutions to problem(0.1)and the asymptotic property of the solutions. 展开更多
关键词 perturbation argument finite dimensional reduction method critical exponent
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Space time fractional KdV Burgers equation for dust acoustic shock waves in dusty plasma with non-thermal ions 被引量:2
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作者 Emad K.El-Shewy Abeer A.Mahmoud +2 位作者 Ashraf M.Tawfik Essam M.Abulwafa Ahmed Elgarayhi 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第7期316-322,共7页
The KdV-Burgers equation for dust acoustic waves in unmagnetized plasma having electrons, singly charged non- thermal ions, and hot and cold dust species is derived using the reductive perturbation method. The Boltzma... The KdV-Burgers equation for dust acoustic waves in unmagnetized plasma having electrons, singly charged non- thermal ions, and hot and cold dust species is derived using the reductive perturbation method. The Boltzmann distribution is used for electrons in the presence of the cold (hot) dust viscosity coefficients. The semi-inverse method and Agrawal variational technique are applied to formulate the space-time fractional KdV-Burgers equation which is solved using the fractional sub-equation method. The effect of the fractional parameter on the behavior of the dust acoustic shock waves in the dusty plasma is investigated. 展开更多
关键词 dust-acoustic waves reductive perturbation method modified Riemann-Liouville fractionalderivative space-time fractional KdV-Burgers equation
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Precise integration method for a class of singular two-point boundary value problems 被引量:2
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作者 Wen-Zhi Zhang Pei-Yan Huang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第2期233-240,共8页
In this paper we present a precise integration method based on high order multiple perturbation method and reduction method for solving a class of singular twopoint boundary value problems.Firstly,by employing the met... In this paper we present a precise integration method based on high order multiple perturbation method and reduction method for solving a class of singular twopoint boundary value problems.Firstly,by employing the method of variable coefficient dimensional expanding,the non-homogeneous ordinary differential equations(ODEs) are transformed into homogeneous ODEs.Then the interval is divided evenly,and the transfer matrix in every subinterval is worked out using the high order multiple perturbation method,and a set of algebraic equations is given in the form of matrix by the precise integration relation for each segment,which is worked out by the reduction method.Finally numerical examples are elaboratedd to validate the present method. 展开更多
关键词 Singular two point boundary value problem Precise integration method High order multiple perturbation method Reduction method
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K-P-Burgers equation in negative ion-rich relativistic dusty plasma including the effect of kinematic viscosity
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作者 A N Dev M K Deka +2 位作者 J Sarma D Saikia N C Adhikary 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期215-221,共7页
The stationary solution is obtained for the K–P–Burgers equation that describes the nonlinear propagations of dust ion acoustic waves in a multi-component, collisionless, un-magnetized relativistic dusty plasma cons... The stationary solution is obtained for the K–P–Burgers equation that describes the nonlinear propagations of dust ion acoustic waves in a multi-component, collisionless, un-magnetized relativistic dusty plasma consisting of electrons, positive and negative ions in the presence of charged massive dust grains. Here, the Kadomtsev–Petviashvili(K–P) equation, threedimensional(3D) Burgers equation, and K–P–Burgers equations are derived by using the reductive perturbation method including the effects of viscosity of plasma fluid, thermal energy, ion density, and ion temperature on the structure of a dust ion acoustic shock wave(DIASW). The K–P equation predictes the existences of stationary small amplitude solitary wave,whereas the K–P–Burgers equation in the weakly relativistic regime describes the evolution of shock-like structures in such a multi-ion dusty plasma. 展开更多
关键词 K–P–Burgers equation negative ion relativistic plasma reductive perturbation method
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The Solitary Waves of the Barotropic Quasi-Geostrophic Model with the Large-scale Orography
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作者 陈炯 刘式适 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1998年第3期122-129,共8页
Starting from a modified barotropic quasi-geostrophic model equation, considering the actual situation of the large-orography of the Tibetan Plateau, neglecting its slope in x direction, and using the reductive pertur... Starting from a modified barotropic quasi-geostrophic model equation, considering the actual situation of the large-orography of the Tibetan Plateau, neglecting its slope in x direction, and using the reductive perturbation method, then the solitary waves are obtained. The results show that the orography is essential factor exciting solitary Rossby waves in a flow without shear. 展开更多
关键词 Barotrophic quasi-geostrophic model reductive perturbation method Solitary wave
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Dust Acoustic Compressive Waves in a Warm Dusty Plasma Having Non-Thermal Ions and Non-Isothermal Electrons
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作者 Apul N.DEV Manoj K.DEKA +1 位作者 Rajesh SUBEDI Jnanjyoti SARMA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第9期721-727,共7页
In this article an investigation is presented on the properties of dust acoustic(DA)compressive solitary wave propagation in an adiabatic dusty plasma,including the effect of nonthermal positive and negative ions an... In this article an investigation is presented on the properties of dust acoustic(DA)compressive solitary wave propagation in an adiabatic dusty plasma,including the effect of nonthermal positive and negative ions and non-isothermal electrons.The reductive perturbation method has been employed to derive the lower degree modified Kadomtsev-Petviashivili(mK-P),3D Schamel-Korteweg-de-Vries equation or modified Kadomtsev-Petviashivili(mK-P) equations for dust acoustic solitary waves in a homogeneous,unmagnetized and collisionless plasma whose constituents are non-isothermal electrons,singly charged positive and negative non-thermal ions and massive charged dust particles.The stationary analytical solutions of the lower degree mK-P and mK-P equations are numerically analyzed,where the effect of various dusty plasma constituents on DA solitary wave propagation is taken into account.It is observed that both the ions in dusty plasma play a key role in the formation of DA compressive solitary waves,and also the ion concentration and non-isothermal electrons control the transformation of the compressive potentials of the waves. 展开更多
关键词 dusty plasma reductive perturbation method non-isothermal ions compressive solitary wave
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Approximate Similarity Reduction for Perturbed Kaup-Kupershmidt Equation via Lie Symmetry Method and Direct Method
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作者 刘希忠 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第11期797-802,共6页
The perturbed Kaup-Kupershmidt equation is investigated in terms of the approximate symmetry perturbationmethod and the approximate direct method.The similarity reduction solutions of different orders are obtainedfor ... The perturbed Kaup-Kupershmidt equation is investigated in terms of the approximate symmetry perturbationmethod and the approximate direct method.The similarity reduction solutions of different orders are obtainedfor both methods, series reduction solutions are consequently derived.Higher order similarity reduction equations arelinear variable coefficients ordinary differential equations.By comparison, it is find that the results generated from theapproximate direct method are more general than the results generated from the approximate symmetry perturbationmethod. 展开更多
关键词 perturbed Kaup-Kupershmidt equation approximate symmetry perturbation method approxi-mate direct reduction method series reduction solutions
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Breather solutions of modified Benjamin-Bona-Mahony equation
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作者 G T Adamashvili 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第2期220-226,共7页
New two-component vector breather solution of the modified Benjamin-Bona-Mahony(MBBM)equation is considered.Using the generalized perturbation reduction method,the MBBM equation is reduced to the coupled nonlinear Sch... New two-component vector breather solution of the modified Benjamin-Bona-Mahony(MBBM)equation is considered.Using the generalized perturbation reduction method,the MBBM equation is reduced to the coupled nonlinear Schr¨odinger equations for auxiliary functions.Explicit analytical expressions for the profile and parameters of the vector breather oscillating with the sum and difference of the frequencies and wavenumbers are presented.The two-component vector breather and single-component scalar breather of the MBBM equation is compared. 展开更多
关键词 modified Benjamin-Bona-Mahony equation generalized perturbation reduction method vector breather nonlinear waves
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基于多车状态变化特征的网联车跟驰模型 被引量:1
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作者 史昕 朱健 +2 位作者 赵祥模 惠飞 马峻岩 《汽车工程》 EI CSCD 北大核心 2023年第8期1309-1319,共11页
针对前车速度单双向突变引起的交通流不稳定问题,提出一种基于多车状态变化特征的网联车跟驰模型(MVSCF)。首先引入多前车加速度差变化特征和优化的速度期望估计改进MVCM模型;然后利用微小扰动法和约化摄动法求解MVSCF模型的临界稳定条... 针对前车速度单双向突变引起的交通流不稳定问题,提出一种基于多车状态变化特征的网联车跟驰模型(MVSCF)。首先引入多前车加速度差变化特征和优化的速度期望估计改进MVCM模型;然后利用微小扰动法和约化摄动法求解MVSCF模型的临界稳定条件,同时结合环形道路场景推导多前车加速度差系数k、多前车数q和多前车最优速度权重ε的相对最优值;最后利用直行道路场景对比分析MVSCF模型在前车速度非平稳变化作用下的交通流稳定效果。仿真结果表明:前车速度单双向突变时,MVSCF模型能够较好吸收前车扰动,速度波动峰谷差值和加速度波动幅度均有所减小,有利于提升交通流的稳定性。 展开更多
关键词 网联车 跟驰模型 最优速度 微小扰动法 约化摄动法
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Dust Acoustic Shock Waves with Non-Thermal and Vortex-Like Ions in Dusty Plasma
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作者 Apul N.DEV Jnanjyoti SARMA +1 位作者 Manoj K.DEKA Nirab C.ADHIKARY 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第4期268-275,共8页
A rigorous investigation is presented on the propagation characteristics of non-linear dust acoustic(DA)waves in an unmagnetized dusty plasma system containing non-thermal and vortex-like ions and Maxwellian electro... A rigorous investigation is presented on the propagation characteristics of non-linear dust acoustic(DA)waves in an unmagnetized dusty plasma system containing non-thermal and vortex-like ions and Maxwellian electrons under the effect of a fluctuating charged dust fluid.The three-dimensional(3D)Burgers'equation and a new form of a lower degree modified 3D Burgers'equation with their analytical solutions are derived to study the features of shock waves in such plasmas.The effect of the population of non-thermal ions,the vortex-like ion parameter as well as the temperature ratios of ions and electrons on the evolution of shock waves in the presence of dust charge fluctuation is presented.This theoretical investigation might be effectively utilized to unveil the nature of many astrophysical plasma environments(Saturn's spokes etc.)where such plasmas are reported to have existed. 展开更多
关键词 dusty plasma reductive perturbation method 3D Burgers' equation modified 3D Burgers' equation tan-hyperbolic method
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甲醇详细燃烧反应动力学模型的简化与多目标优化研究
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作者 毛欢 徐志建 朱勇 《能源化工》 CAS 2023年第2期25-33,共9页
采用基于路径通量分析的直接关系图法(DRGPFA)对甲醇详细机理Mech15.34进行了简化,根据敏感性分析法和指数前因子扰动法相结合的优化策略,以层流火焰速度、重要物种浓度和点火延迟时间为优化目标对甲醇简化机理进行了优化,得到并验证了... 采用基于路径通量分析的直接关系图法(DRGPFA)对甲醇详细机理Mech15.34进行了简化,根据敏感性分析法和指数前因子扰动法相结合的优化策略,以层流火焰速度、重要物种浓度和点火延迟时间为优化目标对甲醇简化机理进行了优化,得到并验证了最终优化机理Vt。研究结果表明,基于DRGPFA的简化机理优化为21种组分、106个基元反应,简化误差适中。与DRGPFA机理相比,优化机理Vt的点火延迟时间的平均误差降低了0.3个百分点,最大误差降低了4.3个百分点;层流火焰速度的平均误差降低了1.5个百分点,最大误差降低了9.3个百分点;CO浓度的平均误差降低了2.4个百分点,最大误差降低了0.9个百分点。最终优化机理Vt较简化机理的预测性能得到了一定的提升。 展开更多
关键词 甲醇 机理简化 多目标优化 敏感性分析 指数前因子扰动法
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非线性弦的变分原理与减缩摄动解法 被引量:12
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作者 吕克璞 洪学仁 +1 位作者 石玉仁 孙建安 《西北师范大学学报(自然科学版)》 CAS 2001年第4期35-39,共5页
用变分原理推导出了非线性弦振动方程 ,并用减缩摄动法 (Reductiveperturbationmethod)
关键词 变分原理 非线性弦 KdV方程 减缩摄动法 弦振动方程 数学物理方程 孤立子
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超KdV方程的减缩摄动解法 被引量:4
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作者 吕克璞 孙建安 +1 位作者 段文山 赵金保 《应用数学和力学》 CSCD 北大核心 2001年第7期753-757,共5页
利用减缩摄动法 (ReductivePerturbationMethod)将超KdV方程变换为普通KdV方程 ,并求出了小振幅摄动解·
关键词 超KdV方程 减缩摄动法 KDV方程 摄动解 特征问题 孤波
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梁中非线性弯曲波传播特性的研究 被引量:7
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作者 刘志芳 王铁锋 张善元 《力学学报》 EI CSCD 北大核心 2007年第2期238-244,共7页
研究了梁中的非线性弯曲波的传播特性,同时考虑了梁的大挠度引起的几何非线性效应和梁的转动惯性导致的弥散效应,利用Hamilton变分法建立了梁中非线性弯曲波的波动方程.对该方程进行了定性分析,在不同的条件下,该方程在相平面上存在同... 研究了梁中的非线性弯曲波的传播特性,同时考虑了梁的大挠度引起的几何非线性效应和梁的转动惯性导致的弥散效应,利用Hamilton变分法建立了梁中非线性弯曲波的波动方程.对该方程进行了定性分析,在不同的条件下,该方程在相平面上存在同宿轨道或异宿轨道,分别对应于方程的孤波解或冲击波解.利用Jacobi椭圆函数展开法,对该非线性方程进行求解,得到了非线性波动方程的准确周期解及相对应的孤波解和冲击波解,讨论了这些解存在的必要条件,这与定性分析的结果完全相同.利用约化摄动法从非线性弯曲波动方程中导出了非线性Schrodinger方程,从理论上证明了考虑梁的大挠度和转动惯性时梁中存在包络孤立波. 展开更多
关键词 非线性弯曲波 大挠度 JACOBI椭圆函数 约化摄动法
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庚酸甲酯高温燃烧化学动力学机理的系统简化和分析 被引量:7
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作者 李树豪 方亚梅 +2 位作者 王繁 李萍 李象远 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2013年第7期1714-1722,共9页
采用详细化学反应动力学机理的系统简化方法,对庚酸甲酯高温燃烧化学动力学机理进行了系统简化.首先采用两步直接关系图法(Directed relation graph method,DRG)和主成分分析(Principle componentanalysis,PCA)方法对由1087个物种、459... 采用详细化学反应动力学机理的系统简化方法,对庚酸甲酯高温燃烧化学动力学机理进行了系统简化.首先采用两步直接关系图法(Directed relation graph method,DRG)和主成分分析(Principle componentanalysis,PCA)方法对由1087个物种、4592步可逆反应组成的庚酸甲酯燃烧的详细机理进行框架简化,得到了包含108个物种、547步基元反应的框架机理.在此框架机理基础上,进一步采用计算奇异值摄动法(Computational singular perturbation,CSP)对框架机理进行时间尺度分析,再选取30个准稳态物种,采用准稳态近似(Quasi steady state approximation,QSSA)方法构建了包含78个物种、74步总包反应的全局简化机理.模拟结果表明,在较宽的参数范围内,框架机理和全局简化机理均能重现庚酸甲酯高温燃烧时的点火延迟、物种浓度分布和熄火等燃烧特性.此外,基于框架机理阐明了庚酸甲酯高温燃烧的反应路径和对点火有重要影响的基元反应.与详细机理相比,框架机理保留了良好的精确性和全局性,可以很好地反映庚酸甲酯的燃烧特性,有助于对生物柴油的燃烧过程的理解. 展开更多
关键词 庚酸甲酯 机理简化 直接关系图 主成分分析 计算奇异值摄动法 准稳态近似
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广义奇异摄动降阶方法在控制器降阶中的应用 被引量:2
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作者 张力军 曾建平 程鹏 《航空学报》 EI CAS CSCD 北大核心 2002年第2期125-129,共5页
首先推导了广义奇异摄动降阶和奇异摄动降阶的 Schur方法 ,解决了均衡变换可能出现病态的问题 ,并且算法具有较好的鲁棒性。然后 ,将其应用于控制器降阶 ,并同其它方法比较 ,认为原系统带宽附近的控制器降阶误差对降阶效果影响较大 ,而... 首先推导了广义奇异摄动降阶和奇异摄动降阶的 Schur方法 ,解决了均衡变换可能出现病态的问题 ,并且算法具有较好的鲁棒性。然后 ,将其应用于控制器降阶 ,并同其它方法比较 ,认为原系统带宽附近的控制器降阶误差对降阶效果影响较大 ,而广义奇异摄动降阶法通过参数α的选择 ,能取得较好的降阶效果。可供工程设计参考。 展开更多
关键词 广义奇异摄动降阶 Schur方法 控制器降阶 鲁棒控制器
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耦合非线性波动方程组的约化摄动分析 被引量:2
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作者 易金桥 郭志荣 +1 位作者 吕克璞 段文山 《西北师范大学学报(自然科学版)》 CAS 2006年第3期37-41,共5页
基于远方场理论的思想,应用约化摄动分析方法对耦合KdV方程和耦合mKdV方程进行了近似求解,并得到了它们的几组孤立波解,与已有结论相比,其振幅的物理意义更加丰富.在特殊情况下,所得到的近似解与精确解具有完全相同的形式.分析表明,所... 基于远方场理论的思想,应用约化摄动分析方法对耦合KdV方程和耦合mKdV方程进行了近似求解,并得到了它们的几组孤立波解,与已有结论相比,其振幅的物理意义更加丰富.在特殊情况下,所得到的近似解与精确解具有完全相同的形式.分析表明,所应用的约化摄动方法在研究小振幅扰动问题方面有一定的普适性. 展开更多
关键词 约化摄动方法 耦合KDV方程组 耦合mKdV方程组
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