非均匀交换各向异性铁磁介质的非线性表面自旋波

利用Landau-Lifshitz 方程，研究了具有非均匀交换各向异性的半无限大铁磁体的非线性表 面自旋波理论。导出了部分钉扎纯交换铁磁介质的磁化强度所满足的边界条件和非线性表面 自旋波的色散关系，并获得了自旋波振幅沿z方向驻波的一维非线性Schrdinger方程和包 络振幅沿平面传播的二维非线性Schrdinger方程，结果表明铁磁体磁化强度的包络振幅随时空变化的性质是由二维非线性Schrdinger方程决定的。因此预言铁磁介质的表面非线性激发应是二维孤波的形式。对于弱非线性表面自旋波，对非线性Schrdinger方程存在孤子形式解的可能性作了讨论. 关键词： 表面自旋波 Landau-Lifshitz方程 非线性Schrdinger方程 孤子     

准连续光抽运光子晶体光纤产生超连续谱中的调制不稳定性(英文)

报道了应用准连续光抽运光子晶体光纤产生超连续谱时的一种现象,并根据调制不稳定和数值解薛定谔方程证明此现象为调制不稳定性.在实验中发现有两个波峰,与中心波长之间的距离分别为27 .08 nm和32 .72 nm,经过对比和分析数值结算和实验结果非常吻合,说明调制不稳定性在准连续光抽运光子晶体光纤产生超连续谱过程中起着重要的作用.     

Optical solitons and modulation instability analysis of the (1+1)-dimensional coupled nonlinear Schrödinger equation

This study successfully reveals the dark, singular solitons, periodic wave and singular periodic wave solutions of the (1+1)-dimensional coupled nonlinear Schrödinger equation by using the extended rational sine-cosine and rational sinh-cosh methods. The modulation instability analysis of the governing model is presented. By using the suitable values of the parameters involved, the 2-, 3-dimensional and the contour graphs of some of the reported solutions are plotted.     

基于复Ginzburg-Landau方程的双核光纤中调制不稳定性的仿真研究

在双核光纤光学系统中,应用复Ginzburg-Landau方程,研究了连续波的不稳定性问题.双核光纤光学系统是由一个非线性离散主核和一个线性附核构成的.研究发现,在线性微扰下存在调制不稳定性.系统仿真结果表明：如果充分考虑调制不稳定性,则该系统将产生规则或者不规则的脉冲序列.反之,如果不考虑调制不稳定性它将产生一连串具有连续增长振幅的离散峰.这表明在反常群速度色散情况下,一串归零脉冲的峰值或者单一归零脉冲峰值仍然是增强的.在光纤中产生归零序列脉冲源,这一研究结果对全光纤通信有一定的价值,对光纤光学及物理学 关键词： 光孤子 复Ginzburg-Landau方程 双核光纤 调制不稳定性     

Nonautonomous solitons in the continuous wave background of the variable-coefficient higher-order nonlinear Schro¨dinger equation

We reduce the variable-coefficient higher-order nonlinear Schrdinger equation (VCHNLSE) into the constantcoefficient (CC) one. Based on the reduction transformation and solutions of CCHNLSE, we obtain analytical soliton solutions embedded in the continuous wave background for the VCHNLSE. Then the excitation in advancement and sustainment of soliton arrays, and postponed disappearance and sustainment of the bright soliton embedded in the background are discussed in an exponential system.     

用数字示波器观测拍与调幅波

介绍了拍与调幅波的原理,提出了利用数字示波器观测拍与调幅波的方法.通过实验观测,加深了对拍和调幅波原理的理解.     

时空调制引起的漫游螺旋波与旅行螺旋波共存现象

以Barkley模型为研究对象, 研究了在时空调制作用下螺旋波时空动力学行为特性. 发现在适当的调制参数的作用下, 能够在同一系统中同时观察到漫游螺旋波与旅行螺旋波. 通过数值模拟研究分析, 给出了能产生漫游螺旋波与旅行螺旋波共存现象的潜在机理, 并详细讨论了在Barkley 模型中要产生这种共存现象的两个必要条件. 关键词： 时空调制 漫游螺旋波 旅行螺旋波     

Singular solitons and other solutions to a couple of nonlinear wave equations

This paper addresses the extended （G′/G）-expansion method and applies it to a couple of nonlinear wave equations. These equations are modified the Benjamin-Bona-Mahoney equation and the Boussinesq equation. This extended method reveals several solutions to these equations. Additionally, the singular soliton solutions are revealed, for these two equations, with the aid of the ansatz method.     

Novel device to measure critical point "Onset" of capillary wave and interpretation of Faraday instability wave by numerical analysis

A capillary wave was created on a surface by vibrating from the bottom of a container. When the amplitude of the container vibration approached the critical point, called the onset state, the surface broke up and bursted into very small drops on the air. The numerical analysis was used to determine the amplitude of the onset. The onset point was found to be 0.349 μm at f = 500 kHz. The critical amplitude h_cr was determined by using a multi-Fourier horn nozzle (MFHN) device. The onset point was measured to be 0.37 μm using a laser Doppler vibrometer (LDV) with the MFHN at f = 486 kHz. These drops indicate that particle size distributions of 10.8 μm and 7.0 μm were produced by the MFHN at f = 289 kHz and f = 486 kHz, respectively. These results agreed with those obtained using Kelvin’s equation, which predicted D = 0.34λ.     

二阶孤子的传输和相互作用

用分步傅里叶变换法求解二阶孤子传输的非线性薛定谔方程, 得到了在此条件下孤子传输的数值图形, 发现二阶孤子在传输中被压缩, 幅值振荡变化。2个二阶孤子在传输过程中没有出现象2个一阶孤子那样周期性碰撞, 但2个二阶孤子时间间隔较小时, 随传输距离在2个二阶孤子中间周期性地衍生出第3个孤子。研究证明：二阶孤子的传输具有与一阶孤子明显不同的特征。     

扩展的(2+1)维浅水波方程的尖峰孤子解及其相互作用

利用改进的 Riccati方程映射法和变量分离法, 得到了扩展的(2+1)维浅水波方程的变量分离解(包括孤波解, 周期波解和有理函数解). 根据得到的孤波解, 构造出了方程的几种不同形状的尖峰孤子结构, 研究了孤子的相互作用.     

Impacts of higher-order dispersions and saturable nonlinearities on modulation instability in negative-refractive metamaterials

On the basis of the standard linear stability analysis and Drude electromagnetic model,the impacts of higher-order dispersions and three kinds of typical saturable nonlinearities on modulation instability(MI) have been analyzed and calculated for negative-refractive metamaterials(MMs).Our results show that the MI gain spectra consist of only one spectral region instead of one or two regions in ordinary materials,which may be close to or far from the zero point.Particularly,the spectrum far from the zero point has a high cut-off frequency but a narrow spectral width,which is obviously beneficial to the generation of high-repetition-rate pulse trains.Moreover,MI characteristics here will vary with the normalized angular frequency which can be modified by adjusting the structures of negative-refractive MMs,signifying the controllability of bistable solitons and MI based applications.The effects of saturable nonlinearities are similar to those in ordinary materials.