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ON THE EXISTENCE OF POSITIVE SOLUTIONS TO SECOND ORDER PERIODIC BVPS 被引量:28
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作者 蒋达清 《Acta Mathematica Scientia》 SCIE CSCD 1998年第S1期31-35,共5页
The existence of positive solutions to second-order periodic BVPs-u'+Mu =j(t, u),t(0) = u(2π),u'(0) = '(2π) and u'+ Mu = I(t, u), u(0) = u(2π), u'(0) = u'(2π)is proved by a simple appliCati... The existence of positive solutions to second-order periodic BVPs-u'+Mu =j(t, u),t(0) = u(2π),u'(0) = '(2π) and u'+ Mu = I(t, u), u(0) = u(2π), u'(0) = u'(2π)is proved by a simple appliCation of a Fixed point Theorem in cones due to Krasnoselskii. 展开更多
关键词 Periodic BVP. positive solutions. the fixed point theorem
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Error Estimations, Error Computations, and Convergence Rates in FEM for BVPs
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作者 Karan S. Surana A. D. Joy J. N. Reddy 《Applied Mathematics》 2016年第12期1359-1407,共49页
This paper presents derivation of a priori error estimates and convergence rates of finite element processes for boundary value problems (BVPs) described by self adjoint, non-self adjoint, and nonlinear differential o... This paper presents derivation of a priori error estimates and convergence rates of finite element processes for boundary value problems (BVPs) described by self adjoint, non-self adjoint, and nonlinear differential operators. A posteriori error estimates are discussed in context with local approximations in higher order scalar product spaces. A posteriori error computational framework (without the knowledge of theoretical solution) is presented for all BVPs regardless of the method of approximation employed in constructing the integral form. This enables computations of local errors as well as the global errors in the computed finite element solutions. The two most significant and essential aspects of the research presented in this paper that enable all of the features described above are: 1) ensuring variational consistency of the integral form(s) resulting from the methods of approximation for self adjoint, non-self adjoint, and nonlinear differential operators and 2) choosing local approximations for the elements of a discretization in a subspace of a higher order scalar product space that is minimally conforming, hence ensuring desired global differentiability of the approximations over the discretizations. It is shown that when the theoretical solution of a BVP is analytic, the a priori error estimate (in the asymptotic range, discussed in a later section of the paper) is independent of the method of approximation or the nature of the differential operator provided the resulting integral form is variationally consistent. Thus, the finite element processes utilizing integral forms based on different methods of approximation but resulting in VC integral forms result in the same a priori error estimate and convergence rate. It is shown that a variationally consistent (VC) integral form has best approximation property in some norm, conversely an integral form with best approximation property in some norm is variationally consistent. That is best approximation property of the integral form and the VC of the integral form is equivalent, one cannot exist without the other, hence can be used interchangeably. Dimensional model problems consisting of diffusion equation, convection-diffusion equation, and Burgers equation described by self adjoint, non-self adjoint, and nonlinear differential operators are considered to present extensive numerical studies using Galerkin method with weak form (GM/WF) and least squares process (LSP) to determine computed convergence rates of various error norms and present comparisons with the theoretical convergence rates. 展开更多
关键词 Finite Element Error Estimation Convergence Rate A Priori A Posteriori BVP Variationally Consistent Integral Form Variationally Inconsistent Integral Form Differential Operator Classification SELF-ADJOINT NON-SELF-ADJOINT Nonlinear
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Legendre-Weighted Residual Methods for System of Fractional Order Differential Equations
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作者 Umme Ruman Md. Shafiqul Islam 《Journal of Applied Mathematics and Physics》 2024年第9期3163-3184,共22页
The numerical approach for finding the solution of fractional order systems of boundary value problems (BPVs) is derived in this paper. The implementation of the weighted residuals such as Galerkin, Least Square, and ... The numerical approach for finding the solution of fractional order systems of boundary value problems (BPVs) is derived in this paper. The implementation of the weighted residuals such as Galerkin, Least Square, and Collocation methods are included for solving fractional order differential equations, which is broadened to acquire the approximate solutions of fractional order systems with differentiable polynomials, namely Legendre polynomials, as basis functions. The algorithm of the residual formulations of matrix form can be coded efficiently. The interpretation of Caputo fractional derivatives is employed here. We have demonstrated these methods numerically through a few examples of linear and nonlinear BVPs. The results in absolute errors show that the present method efficiently finds the numerical solutions of fractional order systems of differential equations. 展开更多
关键词 Fractional Differential Equations System of Fractional Order bvps Weighted Residual Methods Modified Legendre Polynomials
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Numerical Analysis of the Magnetic Dipole Effect on a Radiative Ferromagnetic Liquid Flowing over a Porous Stretched Sheet 被引量:1
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作者 G.Dharmaiah F.Mebarek-Oudina +1 位作者 K.S.Balamurugan N.Vedavathi 《Fluid Dynamics & Materials Processing》 EI 2024年第2期293-310,共18页
The effects of a magnetic dipole on a nonlinear thermally radiative ferromagnetic liquidflowing over a stretched surface in the presence of Brownian motion and thermophoresis are investigated.By means of a similarity t... The effects of a magnetic dipole on a nonlinear thermally radiative ferromagnetic liquidflowing over a stretched surface in the presence of Brownian motion and thermophoresis are investigated.By means of a similarity transformation,ordinary differential equations are derived and solved afterwards using a numerical(the BVP4C)method.The impact of various parameters,namely the velocity,temperature,concentration,is presented graphically.It is shown that the nanoparticles properties,in conjunction with the magnetic dipole effect,can increase the thermal conductivity of the engineered nanofluid and,consequently,the heat transfer.Comparison with earlier studies indicates high accuracy and effectiveness of the numerical approach.An increase in the Brow-nian motion parameter and thermophoresis parameter enhances the concentration and the related boundary layer.The skin-friction rises when the viscosity parameter is increased.A larger value of the ferromagnetic para-meter results in a higher skin-friction and,vice versa,in a smaller Nusselt number. 展开更多
关键词 Brownian motion thermo-phoresis radiation magnetic dipole BVP4C NON-LINEAR
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Computational Investigation of Brownian Motion and Thermophoresis Effect on Blood-Based Casson Nanofluid on a Non-linearly Stretching Sheet with Ohmic and Viscous Dissipation Effects
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作者 Haris Alam Zuberi Madan Lal +1 位作者 Shivangi Verma Nurul Amira Zainal 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第11期1137-1163,共27页
Motivated by the widespread applications of nanofluids,a nanofluid model is proposed which focuses on uniform magnetohydrodynamic(MHD)boundary layer flow over a non-linear stretching sheet,incorporating the Casson mod... Motivated by the widespread applications of nanofluids,a nanofluid model is proposed which focuses on uniform magnetohydrodynamic(MHD)boundary layer flow over a non-linear stretching sheet,incorporating the Casson model for blood-based nanofluid while accounting for viscous and Ohmic dissipation effects under the cases of Constant Surface Temperature(CST)and Prescribed Surface Temperature(PST).The study employs a twophase model for the nanofluid,coupled with thermophoresis and Brownian motion,to analyze the effects of key fluid parameters such as thermophoresis,Brownian motion,slip velocity,Schmidt number,Eckert number,magnetic parameter,and non-linear stretching parameter on the velocity,concentration,and temperature profiles of the nanofluid.The proposed model is novel as it simultaneously considers the impact of thermophoresis and Brownian motion,along with Ohmic and viscous dissipation effects,in both CST and PST scenarios for blood-based Casson nanofluid.The numerical technique built into MATLAB’s bvp4c module is utilized to solve the governing system of coupled differential equations,revealing that the concentration of nanoparticles decreases with increasing thermophoresis and Brownian motion parameters while the temperature of the nanofluid increases.Additionally,a higher Eckert number is found to reduce the nanofluid temperature.A comparative analysis between CST and PST scenarios is also undertaken,which highlights the significant influence of these factors on the fluid’s characteristics.The findings have potential applications in biomedical processes to enhance fluid velocity and heat transfer rates,ultimately improving patient outcomes. 展开更多
关键词 Brownian motion boundary layer flow THERMOPHORESIS bvp4c module viscous dissipation ohmic dissipation partial slip
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Galerkin-Bernstein Approximations for the System of Third-Order Nonlinear Boundary Value Problems
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作者 Snigdha Dhar Md. Shafiqul Islam 《Journal of Applied Mathematics and Physics》 2024年第6期2083-2101,共19页
This paper is devoted to find the numerical solutions of one dimensional general nonlinear system of third-order boundary value problems (BVPs) for the pair of functions using Galerkin weighted residual method. We der... This paper is devoted to find the numerical solutions of one dimensional general nonlinear system of third-order boundary value problems (BVPs) for the pair of functions using Galerkin weighted residual method. We derive mathematical formulations in matrix form, in detail, by exploiting Bernstein polynomials as basis functions. A reasonable accuracy is found when the proposed method is used on few examples. At the end of the study, a comparison is made between the approximate and exact solutions, and also with the solutions of the existing methods. Our results converge monotonically to the exact solutions. In addition, we show that the derived formulations may be applicable by reducing higher order complicated BVP into a lower order system of BVPs, and the performance of the numerical solutions is satisfactory. . 展开更多
关键词 System of Third-Order BVP Galerkin Method Bernstein Polynomials Nonlinear BVP Higher-Order BVP
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MULTIPLE POSITIVE SOLUTIONS TO BVPS FOR HIGHER ORDER NONLINEAR DIFFERENTIAL EQUATIONS IN BANACH SPACES
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作者 戚仕硕 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2001年第2期271-278,共8页
In this article, the author employs the conical expansion and compression fixed point principle and the fixed point index theory to show that there exist at least two positive solutions for a higher order BVP.
关键词 Multiple positive solutions higher order BVP nonlinear differential equation fixed point index Banach space
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Efficient Decomposition Shooting Method for Solving Third-Order Boundary Value Problems
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作者 Nawal Al-Zaid Kholoud Alzahrani +1 位作者 Huda Bakodah Mariam Al-Mazmumy 《International Journal of Modern Nonlinear Theory and Application》 2023年第3期81-98,共18页
The present paper proposes a mathematical method to numerically treat a class of third-order linear Boundary Value Problems (BVPs). This method is based on the combination of the Adomian Decomposition Method (ADM) and... The present paper proposes a mathematical method to numerically treat a class of third-order linear Boundary Value Problems (BVPs). This method is based on the combination of the Adomian Decomposition Method (ADM) and, the modified shooting method. A complete derivation of the proposed method has been provided, in addition to its numerical implementation and, validation via the utilization of the Runge-Kutta method and, other existing methods. The method has been applied to diverse test problems and turned out to perform remarkably. Lastly, the simulated numerical results have been graphically illustrated and, also supported by some absolute error comparison tables. 展开更多
关键词 Linear Third Order bvps Shooting Method Adomian Decomposition Method Two-Point Boundary Value Problem
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Mathematical Study of HD Micropolar Fluid Flow with Radiation and Dissipative Impacts over a Permeable Stretching Sheet:Slip Effects Phenomena
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作者 Pudhari Srilatha Ahmed M.Hassan +1 位作者 B.Shankar Goud E.Ranjit Kumar 《Frontiers in Heat and Mass Transfer》 EI 2023年第1期539-562,共24页
The purpose of this research is to investigate the influence that slip boundary conditions have on the rate of heat and mass transfer by examining the behavior of micropolar MHD flow across a porous stretching sheet.I... The purpose of this research is to investigate the influence that slip boundary conditions have on the rate of heat and mass transfer by examining the behavior of micropolar MHD flow across a porous stretching sheet.In addition to this,the impacts of thermal radiation and viscous dissipation are taken into account.With the use of various computing strategies,numerical results have been produced.Similarity transformation was utilized in order to convert the partial differential equations(PDEs)that regulated energy,rotational momentum,concentration,and momentum into ordinary differential equations(ODEs).As compared to earlier published research,MATLAB inbuilt solver solution shows an extremely good correlation in exceptional instances.In exceptional instances,the present MATLAB inbuilt solver solution has a very excellent connection with the findings of the previously published investigations.A variety of flow field factors impact the Nusselt number,the wall couple shear stress,the friction factor,Sherwood numbers the dimensionless distributions discussed in detail.When the Eckert number rises,the temperature rises,and the Schmidt number falls,the concentration falls.Velocity increases with increases in the material factor but drops with increases in the magnetic parameter and the surface condition factor. 展开更多
关键词 MICROPOLAR RADIATION bvp4c MHD suction/injection
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MHD(SWCNTS+MWCNTS)/H_(2)O-Based Williamson Hybrid Nanofluids Flow Past Exponential Shrinking Sheet in Porous Medium
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作者 Hamzeh Taha Alkasasbeh Muhammad Khairul Anuar Mohamed 《Frontiers in Heat and Mass Transfer》 EI 2023年第1期265-279,共15页
The present study numerically investigates the flow and heat transfer of porous Williamson hybrid nanofluid on an exponentially shrinking sheet with magnetohydrodynamic(MHD)effects.The nonlinear partial differential e... The present study numerically investigates the flow and heat transfer of porous Williamson hybrid nanofluid on an exponentially shrinking sheet with magnetohydrodynamic(MHD)effects.The nonlinear partial differential equations which governed the model are first reduced to a set of ordinary differential equations by using the similarity transformation.Next,the BVP4C solver is applied to solve the equations by considering the pertinent fluid parameters such as the permeability parameter,the magnetic parameter,the Williamson parameter,the nanoparticle volume fractions and the wall mass transfer parameter.The single(SWCNTs)and multi-walled carbon nanotubes(MWCNTs)nanoparticles are taken as the hybrid nanoparticles.It is found that the increase in magnetic parameter in SWCNT+MCWNT hybrid nanofluid results in an increase of 72.2%on skin friction compared to SWCNT nanofluid while maintaining reducing a small number of Nusselt number.This shows the potential of the Williamson hybrid nanofluid for friction application purposes especially in transportation like braking system,flushing fluid and mechanical engineering. 展开更多
关键词 Hybrid nanofluid MHD porous medium BVP4C method
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Existence and Uniqueness Results for a Fully Third-Order Boundary Value Problem
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作者 Xiaoming Liu Yongxiang Li 《Advances in Pure Mathematics》 2023年第8期495-503,共14页
The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have stud... The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained. 展开更多
关键词 Fully Third-Order BVP SOLUTION Positive Solution Existence and Uniqueness Inequality Conditions
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猪2型圆环病毒核酸疫苗免疫效应研究 被引量:13
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作者 宋云峰 肖少波 +2 位作者 金梅林 张松林 陈焕春 《畜牧兽医学报》 CAS CSCD 北大核心 2005年第10期1049-1054,共6页
PCR扩增PCV2 ORF2和BVP22基因。将ORF2基因克隆入真核表达载体pCDNA3.1(+),构建了pCORF2作为核酸疫苗免疫小白鼠。同时将具有蛋白转导功能的BVP22基因分别克隆到ORF2基因的上游和下游,使二者融合表达,命名为pCORF2BVP22和pCBVP22ORF2。... PCR扩增PCV2 ORF2和BVP22基因。将ORF2基因克隆入真核表达载体pCDNA3.1(+),构建了pCORF2作为核酸疫苗免疫小白鼠。同时将具有蛋白转导功能的BVP22基因分别克隆到ORF2基因的上游和下游,使二者融合表达,命名为pCORF2BVP22和pCBVP22ORF2。分4组肌肉免疫BALB/c小白鼠,分别注射pCD-NA3.1(+)、pCORF2、pCORF2BVP22和pCBVP22ORF2,共免疫2次,间隔2周,分别于首免后2周和二免后4周采血,ELISA法检测体液抗体。同时为在体外验证ORF2和BVP22基因的真核表达,将ORF2和BVP22基因分别克隆入pEGFP-N1载体,构建了pNORF2和pNBVP22,转染Hela细胞后在荧光显微镜下观察到了ORF2和BVP22在体外的瞬时高效表达。结果显示,通过两次免疫后,各疫苗组均产生了针对ORF2的体液抗体,同时证明BVP22可增强核酸疫苗的免疫效果,其中以BVP22在ORF2上游效果更好。本研究为防制猪2型圆环病毒感染提供了较为理想的侯选疫苗。 展开更多
关键词 猪2型圆环病毒ORF2 BVP22 蛋白转导 核酸疫苗
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天然气水合物抑制剂BVP性能研究 被引量:6
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作者 全红平 李强 +2 位作者 鲁红升 黄志宇 蔡馨 《科学技术与工程》 北大核心 2013年第6期1442-1445,1452,共5页
随着国内天然气开采规模的日益扩大和深海开采的进行,由天然气水合物所引起的问题,日益受到了石油天然气研究人员的重视。为抑制天然气水合物的生成,急需研究开发出加量少、效率高的水合物抑制剂。为此,自主合成了新型动力学水合物抑制... 随着国内天然气开采规模的日益扩大和深海开采的进行,由天然气水合物所引起的问题,日益受到了石油天然气研究人员的重视。为抑制天然气水合物的生成,急需研究开发出加量少、效率高的水合物抑制剂。为此,自主合成了新型动力学水合物抑制剂BVP。采用自制评价设备,以四氢呋喃法[THF]对其性能进行了评价。评价结果:BVP加量为0.5%~0.75%时,水合物结冰温度为-8℃,过冷度为-10℃。结合天然气水合物抑制剂PVP做性能对比,BVP的性能明显优于PVP;BVP浊点较PVP浊点提高了27.2℃,相同加量条件下BVP承受过冷度较PVP承受过冷度低2~3℃。结合热力学抑制剂复配,最优复配方案:5%~10%NaCl+0.5%BVP,该复配方案下溶液能够承受过冷度达-12℃~-16℃。 展开更多
关键词 天然气水合物 动力学抑制剂 过冷度THF BVP PVP
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双状态切换下BVP振子的复杂行为分析 被引量:3
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作者 陈章耀 王亚茗 +1 位作者 张春 毕勤胜 《力学学报》 EI CSCD 北大核心 2016年第4期953-962,共10页
非线性切换系统具有广泛的工程背景,而传统的非线性理论不能直接用来解决其中的问题,因而成为当前国内外热点和前沿课题之一.目前相关工作大都是围绕固定时间或单状态切换开展的,而实际工程系统大都属于多状态切换问题,同时多状态切换... 非线性切换系统具有广泛的工程背景,而传统的非线性理论不能直接用来解决其中的问题,因而成为当前国内外热点和前沿课题之一.目前相关工作大都是围绕固定时间或单状态切换开展的,而实际工程系统大都属于多状态切换问题,同时多状态切换涉及到更为丰富的动力学行为.本文基于两广义BVP振子,通过引入双向切换开关,构建了双状态切换下的非线性动力学模型,进而研究状态切换导致的各种运动模式及其相应的产生机制.应用非光滑系统的Poincar′e映射理论,推导了双状态切换下的Lyapunov指数的计算公式,结合子系统的分岔分析,得到了切换系统随分岔参数变化的动力学演化过程及其相应的最大Lyapunov指数的变化情况.得到了双状态切换条件下系统存在着各种形式的振荡行为,分析了诸如周期突变等现象及通往混沌的倍周期分岔道路,揭示了不同运动模式的产生机制及倍周期序列的本质.与固定时间切换和单状态切换系统不同,双临界状态切换系统存在着更为丰富的非线性现象,其主要原因在于双状态切换会产生更多的切换点,且切换点的位置更加多变.同时切换系统的倍周期分岔序列与光滑系统中的倍周期分岔序列不同,切换系统的倍周期分岔序列只对应于切换点数目的成倍增加,而其相应的周期一般不对应于严格的周期倍化过程. 展开更多
关键词 切换系统 广义BVP振子 双状态切换 LYAPUNOV指数
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BVP丙烯酸复合型涂料的研究 被引量:2
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作者 郭文录 崔明兰 马登军 《化学世界》 CAS CSCD 1997年第6期318-320,共3页
以BC-01乳液为主要成膜物,VAC乳液及PVA树脂溶液为辅助成膜物,研制成BVP丙烯酸复合型涂料,其性能优于BC-01外墙涂料。本文介绍了该涂料的配方,生产工艺,并列举了涂料的性能指标。
关键词 BVP 复合型 涂料 丙烯酸
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切换断路时间对非线性切换系统振荡特性的影响 被引量:4
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作者 陈章耀 王亚茗 《河南科技大学学报(自然科学版)》 CAS 北大核心 2016年第5期87-90,95,共5页
针对切换断路时间对非线性切换系统影响的问题,构建了非线性混合切换系统数学模型,并以广义Bohffer-Vander Pol(BVP)切换电路为例,进一步画出了不同切换断路时间的切换系统分岔图。对分岔图的分析表明:切换断路时间对切换系统的各种... 针对切换断路时间对非线性切换系统影响的问题,构建了非线性混合切换系统数学模型,并以广义Bohffer-Vander Pol(BVP)切换电路为例,进一步画出了不同切换断路时间的切换系统分岔图。对分岔图的分析表明:切换断路时间对切换系统的各种振荡行为如混沌解和周期解等会产生不同程度的影响。另外,考虑切换断路时间情况下,切换系统还会产生一种特殊的倍周期分岔行为。 展开更多
关键词 非线性动力系统 混合切换 切换断路时间 广义BVP系统
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关于奇摄动拟线性系统 被引量:4
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作者 刘光旭 《应用数学和力学》 EI 1987年第11期967-976,共10页
本文目的在于对非线性两点边值问题(1.1)证明其解存在的充分条件。并利用这一结果研究拟线性弱耦合奇摄动系统(DP)_q的边界层现象。
关键词 奇摄动系统 边界层 定义 附面层 流体层 BVP 边值问题 数学问题 拟线性 退化解 定理 分量 右导数 左导数
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耦合连续BVP振子中的分支现象 被引量:1
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作者 饶明贵 冯广庆 《河南科学》 2008年第9期1017-1020,共4页
对有阻尼的耦合的连续BVP振子,利用平衡点理论和分支定理,分析系统平衡点的存在和稳定性以及存在的分支现象,通过matlab程序对振子数值模拟,给出图像并验证理论结果.
关键词 BVP振子 平衡点 分支
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“工程电磁场”课程教学方法探讨 被引量:5
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作者 卢斌先 《电气电子教学学报》 2012年第3期96-98,共3页
"工程电磁场"课程基本概念抽象,对数学知识要求高,课程涉及问题复杂。笔者从边值问题BVP入手,应用Matlab软件和ANSYS软件,以课堂仿真例子来展示建立边值问题的基本概念,通过仿真作业提高学生对边值问题求解过程的系统了解,以... "工程电磁场"课程基本概念抽象,对数学知识要求高,课程涉及问题复杂。笔者从边值问题BVP入手,应用Matlab软件和ANSYS软件,以课堂仿真例子来展示建立边值问题的基本概念,通过仿真作业提高学生对边值问题求解过程的系统了解,以实验的方式提高学生学习兴趣,巩固其理论知识,并结合工程问题为仿真作业和实验建立了丰富的边值问题库。 展开更多
关键词 工程电磁场 边值问题BVP 数值仿真
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离散的改进型BVP振子混沌行为研究
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作者 夏清华 苏小义 +1 位作者 畅兴平 马华玲 《湖北大学学报(自然科学版)》 CAS 北大核心 2011年第2期139-142,共4页
在BVP方程的基础上,提出一个改进型BVP振子模型,并研究该模型在离散化后的动力学行为.同时利用Matlab进行数值模拟,描绘该模型在离散化后的分岔图以及不同参数情况下的相图、Lyapunov指数图,其结果证实理论分析.
关键词 BVP振子 分岔 混沌 数值模拟
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