Based on MNLS,by using the method of variational principle,the influence of fifth-order nonlinearity on the propagation of soliton-like pulses in fiber is investigated,the evolution equations for the parameters are deduced,the relations between width and distance, chirp and width,are calculated and the evolution equations for frequency and phase are studied by using Runge-Kutta algorithm.

Based on modified nonlinear Schr(?)dinger equation,the differential equations for evolution of parameters of bright-soliton-like pulses in optical fibers were derived by using variational method,and the differential equations were numerically solved by Runge-Kutta algorithm.

The fourth order Runge-Kutta method is used to transform the mathematics model into discrete simulation model,using MATLAB7.

Based on analyzing several numerical method commonly used in digital simulation of power systems,this paper present a new digital simulation method-R-K-T method,which combines Runge-Kutta method with trapezoidal integeration one.

A Simple Application of Runge-kutta in Fuzzy Control;

The Improvement of the Variational Step Method Based on Runge-Kutta;

The 4th order Runge-Kutta and differential approaches combined with spline or polynomial fit were used to work out these parameters, and the effects of deviation and amount of experimental data on the calculated results were analyzed in detail.