三螺旋蛋白质中孤立子的温度效应

在作者已给出的描述三螺旋蛋白质分子的哈密顿函数基础上，得到了孤立子存在的临界温度和热容器，其结果与实验结果一致。     

A Bose-Einstein condensate wave-packet as a soliton in an ideal potential well

The normalized soliton wave-functions corresponding to Bose-Einstein condensate (BEC) wave-packets are studied by an analogy to the solutions of the optical cubic Schrödinger equation. In addition, the two fundamental invariants associated with BEC are evaluated.     

Simulations of rare events in fiber optics by interacting particle systems

In this paper we study the robustness of linear pulses, solitons, and dispersion-managed solitons, under the influence of random perturbations. First, we address the problem of the estimation of the outage probability due to polarization-mode dispersion. Second, we compare the pulse broadening due to random fluctuations of the group-velocity dispersion. We use an original interacting particle system to estimate the tails of the probability density functions of the pulse widths. A new adaptative Monte Carlo method is applied that enforces the simulations to probe the regions of practical importance by selection and mutation steps.     

Symbolic computation on the Darboux transformation for a generalized variable-coefficient higher-order nonlinear Schrödinger equation from fiber optics

Considering the propagation of ultrashort pulse in the realistic fiber optics, a generalized variable-coefficient higher-order nonlinear Schrödinger equation is investigated in this paper. Under certain constraints, a new 3×3 Lax pair for this equation is obtained through the Ablowitz-Kaup-Newell-Segur procedure. Furthermore, with symbolic computation, the Darboux transformation and nth-iterated potential transformation formula for such a model are explicitly derived. The corresponding features of ultrashort pulse in inhomogeneous optical fibers are graphically discussed by the one- and two-soliton-like solutions.     

Solitary wave solutions for a coupled pair of mKdV equations

Propagation of weakly nonlinear long waves is studied within the framework of a system of two coupled modified Korteweg-de Vries equations. We investigate analytically and numerically the various families of soliton states for the considered model. By scaling the functions and variables we find that the resulting coupled pair of equations has only one combined parameter. This parameter depends on the wave speed and the coupling coefficient. Explicit analytical expressions for both of the symmetric and antisymmetric states are determined. Numerical method is derived to solve the proposed system, many numerical tests have been conducted to study the behavior of the solution, and the existence of the asymmetric soliton states is displayed numerically.     

Semi-discrete breather in a helicoidal DNA double chain-model

The nonlinear dynamics of DNA molecular chain is studied for longitudinal and transversal motions through a new discrete helicoidal zigzag model with four degrees of freedom. We take into account the Stokes and hydrodynamical viscous forces. In the semi-discrete approximation, we show that the coupled nonlinear partial differential equations for the longitudinal and transversal out-of-phase motions can be reduced to the nonlinear Schrödinger equation with complex coefficients, allowing analytical breather soliton solution. We found analytically as well as numerically that increasing the damping constant reduces the amplitude and increases the width of the soliton. When the zigzag angle decreases, the height of the soliton increases, but its width remains constant. The linear stability analysis of the system is performed. The growth rate of the instability and the instability regions are discussed as the functions of damping constant, zigzag angle and system parameters.     

色散缓变光纤中宽带调制不稳定性谱的产生

本文报道色散缓变光纤中调制不稳定性效应研究.从非线性Schrodinger方程出发,获得了增益谱与纵向色散变化参量和光纤传输距离的一般关系.研究发现,色散缓变光纤中调制不稳定性的增益谱较常规光纤中的宽得多.调节光纤色散纵向变化参量,可以得到较宽的增益谱.该文的研究结果为光纤中利用调制不稳定性产生超短孤子脉冲提供了理论根据.     

Surface Manipulation of Conjugated Carbon Materials with Scanning Probe Technique

The atomic force microscope (AFM) was used to manipulate surface structures of conjugated carbon materials (graphite and C₇₀) in the nanometer scale with real space resolution. Soliton superlattice was directly observed on both graphite and C₇₀ single crystals surface. The tip-induced dynamic structural changes were also investigated. 丁he manipulations of both sp³-like line defects on the lattice of graphite and individual C₇₀ molecules on defect-free surface or at molecular layer edges were suggested.