共查询到20条相似文献,搜索用时 78 毫秒
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面向边界限制的自聚焦振荡型响应函数系统建立了二阶和三阶非线性共同作用时的二次孤子理论模型.在此基础上,通过数值模拟对有三阶非线性效应和无三阶非线性效应情况下的孤子解进行对比,研究了三阶非线性效应对该系统中二次孤子的影响.结果表明,在孤子波形方面,三阶非线性影响较小,仅轻微改变其横向分布.但是在孤子的存在区间方面,三阶非线性导致孤子只存在于强非局域和一般非局域情况,在弱非局域情况下找不到相应的孤子.此外,三阶非线性的存在还减少了孤子拓展半周期的个数.而在孤子稳定性方面,三阶非线性则缩减了孤子的稳定区间. 相似文献
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研究了非宇称时间对称复数势下非线性耦合器中多类型非局域孤子的存在性和稳定性,发现基态孤子、偶极孤子、多极孤子分别从线性谱中不同的离散特征值分叉出来形成孤子族,其功率受非局域程度和传播常数的影响.在相变以下,各个类型孤子均在相对较低功率区间是稳定的.随着非局域程度的增加,基态孤子族的稳定区域变小,其他孤子族的稳定区域则变大.在相变以上,基态孤子则在相对中功率区是稳定的,并且从第二大离散特征值分叉出的偶极孤子不存在稳定区域.孤子线性稳定性分析结果中的特征值总是以共轭对的形式出现.此外,还研究了耦合系数对孤子态的影响. 相似文献
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研究了一维非局域非线性耦合器中多极亮孤子的存在条件和稳定传输.用牛顿迭代法得到了二极和三极亮孤子.由于较强的非局域响应诱导孤子间的吸引作用比排斥作用大,此时二极孤子不能稳定传输,两孤子相互吸引,融合成一个孤子.随着非局域参数的减小,非线性效应和衍射效应达到平衡时,二极孤子能稳定传播.随着传播常数的减小,孤子的幅值减小,束宽变窄,使得孤子能稳定传播.对于三极亮孤子,在非局域参数较小的时候,耦合的两个三极孤子都不能进行稳定传输.传输一段距离后三极孤子发生碰撞,融合成两极孤子,两极孤子继续传输,最终融合成为一束振荡的光束.随着非局域参数的增大,三极孤子传播的稳定性增强.当传播常数取负数时,随着其绝对值的减小,三极亮孤子的幅值增大,束宽减小,孤子传播的稳定性增强.最后,通过加入白噪声进一步验证了这些亮孤子传播稳定性. 相似文献
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光束在非局域非线性介质中传输由非局域非线性薛定谔方程描述.讨论了在不同非局域程度 条件下,空间光孤子的传输特性.提出了一个基于分步傅里叶算法数值求解孤子波形和分布 的迭代算法.假定介质的非线性响应函数为高斯型,得出了在不同非局域程度条件下空间光 孤子的数值解,并数值证明了它们的稳定性.结果表明,不论非局域程度如何,光束都能以 光孤子态在介质中稳定传输.光孤子的波形是从强非局域时的高斯型过渡到局域时的双曲正 割型,形成孤子的临界功率随非局域程度的减弱而减小,光孤子相位随距离线性增大,相位 的变化率随非局域程度的减弱而减小.
关键词:
非局域非线性薛定谔方程
空间光孤子
临界功率
相位 相似文献
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利用扩展的双曲函数法得到了combined KdV-mKdV (cKdV)方程的几类精确解,其中一类为具有扭结—反扭结状结构的双扭结单孤子解.在不同的极限情况下,该解分别退化为cKdV方程的扭结状或钟状孤波解.理论分析表明,cKdV方程既有传播型孤立波解,也有非传播型孤立波解.文中对双扭结型孤立波解的稳定性进行了数值研究,结果表明,cKdV方程既存在稳定的双扭结型孤立波,也存在不稳定的双扭结型孤立波.
关键词:
cKdV方程
双扭结单孤子
稳定性 相似文献
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本文构造了耦合自散焦饱和非线性薛定谔方程,通过改变势函数参数再利用功率守恒的平方算符法,得到偶极-偶极、三极-偶极以及偶极-三极矢量孤子解.随着孤子功率的增大,这3类矢量孤子均能存在,它们的存在性明显受到势函数的调制.本文给出了3类矢量孤子由势函数调制的存在区域.3类矢量孤子的稳定区域受每个分量的孤子功率调制.随着两分量孤子功率的增大,3类矢量孤子的稳定域均逐渐扩大.当饱和非线性强度增大时,三极-偶极和偶极-三极矢量孤子由稳定状态到不稳定状态临界点对应的孤子功率值逐渐降低.而偶极-偶极矢量孤子由稳定状态到不稳定状态临界点对应的孤子功率值并不会因为饱和非线性强度增大而变化. 相似文献
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Raman spectroscopy is shown to be useful as a tool for long‐term stability studies. The stability of a novel submicron‐size γ‐polymorph form of the explosive HMX (octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine) was monitored up to 1 year using Raman spectroscopy. The preparation and characterization of this submicron HMX has been previously discussed. It is important to know the long‐term stability of this submicron γ‐polymorph material under ambient conditions for its eventual utilization. This submicron HMX material has been found to be stable both chemically and polymorphically (to the order of 1% impurity level), even though HMX normally converts to the β‐polymorph at ambient conditions. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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以力学系统(非线性振动),热力学系统(气液相变与铁磁相变)及光学系统中的几种双稳现象为实例,采用初等方法阐明系统的稳定性与双稳的基本原理。 相似文献
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Summary Some results obtained introducing two-unit generalized complex numbers to determine Mandelbrot and Julia sets for quadratic
maps are presented. We also highlight some analogies and differences between classic complex numbers and one of the proposed
extensions.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Capanello, Italy, July 4–8, 1994. 相似文献
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Summary It is observed that Hartmann flow sustains wave propagation in its centre region for waves whose phase speed is less than
the maximum flow speed. Similar to the previous observations it is found that viscous boundary layers around the critical
level and at the wall replace the exponential regions and wave sinks required for over-reflection in the inviscid flow. The
uniform magnetic field stabilizes the flow for small-wave-number disturbances along thez-direction. Over-reflection is confined to a few ranges of phase speeds for which the two boundary layers are close together
rather than widely separated. These ranges correspond exactly to those for which unstable eigenmodes exist. Over-reflection
is associated with a wave phase tilt opposite in direction to the shear.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
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Summary Suitable transformations are used to convert the two-component Lorenz model for double-diffusion, Soret-driven convection
and the laser with saturable absorber into either a Duffing oscillator equation or a system of two coupled Duffing oscillators.
Then we discuss the range of parameter values where complete integration is possible. 相似文献
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We study the viscous and inviscid stability of shock waves in barotropic and full magnetohydrodynamics. We show that there are magnetohydrodynamic shock waves that are one-dimensionally stable as viscous shock profiles while they are multidimensionally strongly unstable as planar shock discontinuities. 相似文献
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Summary The oscillatory motion of a liquid-liquid interface induced by the Marangoni effect,i.e. the variation of surface tension with the concentration of a surfactant, is described as the harmonic oscillation of the
surfactant concentration at the interface. Then, at vanishing damping, threshold values and parameter regions for sustainedlongitudinal (Marangoni-Lucassen) waves are given in terms of the transport coefficients of the two liquids.
To speed up publication, the authors of this paper have agreed to not receive the proofs for correction. 相似文献
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