激发媒质中的非线性波动力学

本文报道了激发媒质中非线性动力学的最新进展,特别以心室纤维性颤动、化学涡波和大脑皮层扩布性阻抑作为例子。对于进一步的研究和应用也作了讨论。     

New Explicit Solitary Wave Solutions and Periodic Wave Solutions for the Generalized Coupled Hirota－Satsuma KdV system

In this paper,we study the generalized coupled Hirota-Satsuma KdV system by using the new generalized transformation in homogeneous balance method.As a result,many explicit exact solutions,which contain new solitary wave solutions,periodic wave solutions,and the combined formal solitary wave solutions,and periodic wave solutions ,are obtained.     

Bifurcation,Bi—instability and Area Principle for the Solitary Waves of the Nonlinear Wave Equation with Quartic Polynomial Potential

For the nonlinear wave equation with quartic polynomial potential,bifurcation,bi-instability and solitary waves are investigated.An area principle based on the bifurcation diagram is found for the existence of bright and dark solitary waves and shock waves.The simple forms of solitary wave solutions are given by an approximate analytic method.     

Parametrically Driven Solitons in a Chain of Nonlinear Coupled Pendula with an Impurity

The system consisting of a chain of parametrically driven and damped nonlinear coupled pendula with a mass impurity is studied by means of a discrete version of the envelope function approach. An analogue of the parametrically driven damped nonlinear Schodinger equation with an impurity term is derived from the original lattice equation. Analytical solutions of impurity pinned high-frequency breathers and kinks are obtained. The results show that the mass impurity has striking influence on the high-frequency modes. In addition, we perform numerical simulations, showing that the light mass impurity has a stabilizing effect on the chain. The breathers seeding chaos in the homogeneous chain are pinned on a suitable light impurity to pull the chain from the chaotic state.     

线性与非线性波的Chebyshev广义有限谱模拟

给出求解二维线性与非线性波的Chebyshev广义有限谱模拟方法.结合时间层次的高精度预报-校正方法，模拟了二维线性浅水驻波和波在浅滩的非线性变形.方法能够准确模拟水波的物理特征. 关键词： Chebyshev广义有限谱 线性波 非线性波     

非线性振动、非线性波与Jacobi椭圆函数

介绍用较易懂且简捷的Jacobi椭圆函数解法求非线性振动与非线性波的解析解,并以单摆,达芬(Duffing)振子,KdV方程,正弦戈登(Gordon)方程(SG方程),非线性薛定谔方程(NLS方程)的椭圆函数解,钟形孤立波解,扭结与反扭结波解,呼吸子解,扭结波与反扭结波迎头碰撞及包络型孤立子波解等重要实例,给出了说明．     

反常波海面参数计算方法及其色散关系

提出了一种计算反常波海面参数及色散关系的数值方法.将反常波海面看成变幅变频的波列,在各个具体时间、空间点用不同参数的延拓正弦波进行插值.在具体的时间、空间点处,根据海面及其一阶、二阶导数关系,求出相应的延拓正弦波各个参数.数值模拟出的振幅结果表明该方法有效,利用该方法计算的反常波海面参数进行海面重构的结果与原海面完全符合.比较非线性海面波数和角频率的关系式ω²/k与重力加速度g值,发现反常波海面的主要非线性色散区域不是位于反常波区域,而是位于 关键词： 反常波 非线性 色散     

无所不在的波动

文章从自然、科学领域到人文、社会领域论述了一种共有的运动规律形式——波动，认为波动是一种基本的运动形式，它存在于人类几乎所有的认识领域中。     

Electron Single and Double-slit Diffraction in the Temporal Domain

Few-cycle pulses with stable and controllable relative phase between the carrier wave and the envelope （CE phase） have become available as research tools. The actual shape of the electric field of such a pulse strongly depends on this phase, and so do the physical processes the pulse generates. Owing to its pronounced nonlinearity, above-threshold ionization （ATI） provides an excellent example. In particular, the rescattering-induced high- energy part of the ATI spectrum exhibits a dramatic dependence on the value of the CE phase. Moreover, the backward/forward symmetry of the ATI spectrum generated by a, long pulse is broken by a few-cycle pulse. Therefore, analyzing the spectrum in two opposite directions provides a very accurate means of measuring the CE phase.     

一维非线性点阵中的孤子

报道在带阻尼参数激励下的一维非线性点阵中所观察到的非传播孤子现象。并在理论上采用多重尺度展开法把同相和错相的孤子与扭结实验结果归入立方非线性Schr?dinger方程的理论框架。根据非线性Schr?dinger方程,我们预言在这种实验点阵中,自局域结构的波型只取决于点阵的固有参量,而与激励参数无关。 关键词：     

聚（2,5—二丁氧基）苯撑的三阶非线性光学性质

报道了一种新的同可溶性好的，具有连苯结构的共轭有机聚合物；聚（２，５－二丁氧基）苯撑，采用四波混频方法测量了它在５３２ｎｍ和１０６４ｎｍ处的三阶非线性光学系数，由此推算出了非线性折射率，并讨论了的优质因子，指出了材料最适用的光波段。     

各向同性固体介质中的高阶非线性系数

到目前为止,人们对自然界岩石非线性系数的量级范围甚至它们的符号都没有确定的结论。本文作者对他以前的理论作了进一步研究,结果表明,奇阶非线性系数只与奇阶非线性谐波的振幅有关;偶阶非线性系数只与偶阶谐波振幅有关,各阶谐波存在积累解,它的振幅与距离一次方成正比的。应用已发表的波谱测量数据对Berea砂石样品的2~5阶非线性系数做了计算。结果表明,2阶和3阶非线性系数的符号为负,4阶和5阶非线性系数的符号为正。由于非线性系数与声场频谱测量的精度密切相关,本文认为对测得的声场频谱需要作探针接收器灵敏度和测量位置变化的修正。      

Interactions between Solitons and Cnoidal Periodic Waves of the Gardner Equation

The Gardner equation is one of the most important prototypic models in nonlinear physics. Many scholars pay much attention to the Gardner equation and various nonlinear excitations of the Gardner equation have been found by many methods. However, it is very difficult to find interaction solutions among different types of nonlinear excitations. In this work, with the help of the Riccati equation, the Gardner equation is solved by the consistent Riccati expansion. Furthermore, we obtain the soliton-cnoidal wave interaction solutions of the Gardner equation.     

载流有界等离子体柱中的剪切阿尔芬波涡旋

本文采用二流体方程组，研究低β（ｍｅ／ｍｉ＜＜β＜＜１）载流有界等离子体柱中的非线性剪切阿尔芬波，求得一类新的电磁涡旋解。在这类解中，扰动电场和扰动磁场的局域结构由单极部分和多极部分组成，而扰动密度是多极涡旋结构。这些相干结构以一定的角速度整体地绕等离子体柱轴运行。对于本文所取的参数，平衡电流对扰动电磁场和密度的涡旋结构无影响。     

非线性漂移波在行波扰动下的绕数分岔与超级结构

在文献[1]中,数字计算揭示出在时空周期场驱动下,有阻尼的非线性漂移波方程其分岔图显示出某种标度的超级结构。本文指出,漂移波方程的扰动解与未扰系统的解之间的共振和因此而引起的绕数分岔,是出现这种超级结构的原因。由此计算的波数与频率之间的标度关系,与数字实验结果符合。 关键词：     

四波混频在长距离相干光纤传输中的影响

本文研究光纤非线性现象之一的四波混频对长距离相干多路光纤传输系统的影响.通过对一条长度为550km,采用9个掺铒光纤放大器的频分复用系统的实验,清楚地观察到了四波混频这一光纤非线性.实验的结果符合对四波混频的理论分析与计算.结果表明:对信息容量在每秒10~9bit数量级,采用常规的不归零码作信号方式的多路传输,光纤中的四波混频现象将严重地影响其传输性能.     

New Cnoidal and Solitary Wave Solutions of Coupled Higher-Order Nonlinear SchrSdinger System in Nonlinear Optics

The coupled higher-order nonlinear Schroedinger system is a major subject in nonlinear optics as one of the nonlinear partial differential equation which describes the propagation of optical pulses in optic fibers. By using coupled amplitude-phase formulation, a series of new exact cnoidal and solitary wave solutions with different parameters are obtained, which may have potential application in optical communication.     

Asymmetry in Negative Refraction of Nonlinear Waves

Recently, inwardly propagating waves （called antiwaves, AWs） in nonlinear oscillatory systems have attracted much attention. An interesting negative refraction phenomenon has been observed in a bidomain system where one medium supports forwardly propagating waves （normal waves, NWs） and the other AWs. In this paper we find that negative refraction （NR） in nonlinear media has an asymmetric property, i.e., NR can be observed only by applying wave source with proper frequency to one medium, but not the other. Moreover, NR appears always when the incident waves are dense and the refractional waves are sparse. This asymmetry is a particular feature for nonlinear NR, which can neither be observed in linear refraction processes （both positive and negative refractions） nor in nonlinear positive refraction. The mechanism underlying the asymmetry of nonlinear NR are fully understood based on the competition of nonlinear waves.