（2+1）维耗散长波方程与(2+1)维Broer-Kaup方程新的类多孤子解

进一步拓广齐次平衡法的应用，并对关键的操作步骤进行了改进，从而简便地求出了（2+1 ）维耗散长波方程和（2+1）维Broer-Kaup方程新的类多孤子解-这种解更具有一般性，它包 含着已有文献给出的类多孤子解- 关键词： 齐次平衡法 类多孤子解 （2+1）维耗散长波方程 （2+1）维Broer-Kaup方程     

(2+1)维Broer-Kaup方程的广义dromion解结构

利用推广的齐次平衡方法,首先将(2+1)维Broer-Kaup方程线性化,然后构造出丰富的广义孤子解,包括单孤子解,单曲线孤子解,单dromion解,多dromion解。此方法直接而简单,可推广应用一大类(2+1)维非线性可积方程。     

变系数(2+1)维Broer-Kaup方程的新精确解

通过一个简单的变换,变系数(2+1)维Broer-Kaup方程被简化为人们熟知的变系数Burgers方程.利用近年来广泛使用的齐次平衡法和tanh-函数法,获得了变系数(2+1)维Broer-Kaup方程的一些新的精确解.     

变系数(2+1)维Broer-Kaup方程的新精确解P

通过一个简单的变换,变系数(2+1)维Broer-Kaup方程被简化为人们熟知的变系数Burgers方程.利用近年来广泛使用的齐次平衡法和tanh-函数法,获得了变系数(2+1)维Broer-Kaup方程的一些新的精确解.     

(2+1)维Broer-Kaup方程的局域分形结构

进一步拓广齐次平衡法的应用，研究了(2+1)维Broer-Kaup方程的局域分形结构.根据齐次平衡原则，得到方程的B?cklund变换，将方程变换为一个线性化的方程，然后由具有两个 任意函数的种子解构造出一个精确解.利用Jacobian椭圆函数得到了特殊的分形结构. 关键词： 齐次平衡法 (2+1)维Broer-Kaup方程 分形结构     

变系数(2+1)维Broer-Kaup系统的特殊孤子结构及孤子的裂变和湮没现象

利用改进的Riccati方程映射法，得到了变系数(2+1)维 Broer-Kaup 系统的孤波解、周期波解和变量分离解.根据得到的孤波解，构造出了系统的几种不同形状的孤子结构，研究了孤子的裂变和湮没现象. 关键词： 变系数(2+1)维 Broer-Kaup 系统 孤子结构 裂变 湮没     

变系数（2＋1）维Broe-Kaup方程的新精确解

通过一个简单的变换，变系数(2 1)维Broer-Kaup方程被简化为人们熟知的变系数Burgers方程。利用近年来广泛使用的齐次平衡法和tanh-函数法，获得了变系数(2 1)维Broer-Kaup方程的一些新的精确解。     

变系数(2+1)维Broer-Kaup方程的精确解

利用齐次平衡原则,导出了变系数(2+1)维Broer-Kaup方程的B?cklund变换(BT),并由该BT,求出了(2+1)维Broer-Kaup方程的各种形式的精确解.     

高阶Broer-Kaup(BK)方程组的新精确解

利用扩展齐次平衡法,我们得到了1+1维和2+1维高阶BK方程组新的孤子解和无穷多有理函数解,尤其是求出了初始值问题解的封闭形式.     

(2+1)维Broer-Kaup方程的局域相干结构

利用推广的齐次平衡方法,研究了(2+1)维BroerKaup方程的局域相干结构.首先根据领头项分析,给出了这个模型的一个变换,并把它变换成一个线性化的方程,然后由具有两个任意函数的种子解构造出它的一个精确解,发现(2+1)维BroerKaup方程存在相当丰富的局域相干结构.合适的选择这些任意函数,一些特殊型的多dromion解,多lump解,振荡型dromion解,圆锥曲线孤子解,运动和静止呼吸子解和似瞬子解被得到.孤子解不仅可以存在于直线孤子的交叉点上,也可以存在于曲线孤子的交叉点或最临近点上.呼吸子在幅度和形状上都进行了呼吸.本方法直接而简单,可推广应用一大类(2+1)维非线性物理模型. 关键词： 浙江师范大学非线性物理研究室 金华321004 浙江海洋学院物理系 舟山316004     

Optical surface modes of lattice vibrations

Two simple methods, based on simple crystal models, for estimating the longitudinal optical surface vibration mode frequencies which lie in a LALO gap are examined. One method consists of deriving and solving a single-variable equation for the surface mode frequency, which depends only on the experimental bulk dispersion curves. The other method consists of fitting the known dispersion curves of a simple one-dimensional model, for which the optical surface mode frequency is given by a simple expression, to experimental bulk dispersion curves of more complex crystals. The results are compared with detailed theoretical surface mode calculations. The latter method is found to give better estimates.     

The Locally Conservative Galerkin (LCG) Method — a Discontinuous Methodology Applied to a Continuous Framework

This paper presents a comprehensive overview of the element-wise locally conservative Galerkin (LCG) method. The LCG method was developed to find a method that had the advantages of the discontinuous Galerkin methods, without the large computational and memory requirements. The initial application of the method is discussed, to the simple scalar transient convection-diffusion equation, along with its extension to the Navier-Stokes equations utilising the Characteristic Based Split (CBS) scheme. The element-by-element solution approach removes the standard finite element assembly necessity, with an face flux providing continuity between these elemental subdomains. This face flux provides explicit local conservation and can be determined via a simple small post-processing calculation. The LCG method obtains a unique solution from the elemental contributions through the use of simple averaging. It is shown within this paper that the LCG method provides equivalent solutions to the continuous (global) Galerkin method for both steady state and transient solutions. Several numerical examples are provided to demonstrate the abilities of the LCG method.     

如何“写”出平面简谐波的波函数

介绍了大学物理课堂中讲授平面简谐波波函数的一种教学设计,其核心是在课堂教学中归纳总结出平面简谐波波函数的一般形式,为学生提供处理波函数问题的简单方法,该方法只要给定任意点的振动方程及波的传播方向,就可依据一般形式"写"出平面简谐波的波函数.     

Simple functional-differential equations for the bound-state wave-function components

We present a new method of a direct derivation of differential equations for the wave-function components of identical-pariticles systems. The method generates in a simple manner all the possible variants of these equations. In some cases they are the differential equations of Faddeev of Yakubovskii. It is shown that the case of the bound states allows to formulate very simple equations for the components which are equivalent to the Schrödinger equation for the complete wave function. The components with a minimal antisymmetry are defined and the corresponding equations are derived.     

AB initio calculations of the electronic properties of polyethylene

Previous studies of simple polymers have produced energy bands and densities of states which are not in good agreement with each other. We present here an accurate non-parametric method for determining the electronic energy levels of simple polymers, and apply this method to several simple polymers, both with and without impurity side groups.     

Generating Simple Random Graphs with Prescribed Degree Distribution

Let F be a probability distribution with support on the non-negative integers. Four methods for generating a simple undirected graph with (approximate) degree distribution F are described and compared. Two methods are based on the so called configuration model with modifications ensuring a simple graph, one method is an extension of the classical Erdös-Rényi graph where the edge probabilities are random variables, and the last method starts with a directed random graph which is then modified to a simple undirected graph. All methods are shown to give the correct distribution in the limit of large graph size, but under different assumptions on the degree distribution F and also using different order of operations.     

Finite-time synchronization for a class of chaotic and hyperchaotic systems via adaptive feedback controller

This Letter investigates chaos synchronization of chaotic and hyperchaotic systems. Based on finite-time stability theory, a simple adaptive control method for realizing chaos synchronization in a finite time is proposed. In comparison with previous methods, the present method is not only simple, but could also be easily utilized in application. Numerical simulations are given to illustrate the effectiveness and validity of the proposed approach.     

Estimation of resonant peak amplitudes

A simple method is proposed for estimating the resonant peak response levels of damped structures, by using an analysis of undamped vibration. The method is based on a simple identity which is exact for a single degree of freedom system and approximate for more general systems. However, since the level of damping in practical structures can seldom be described with any precision, it is argued that a simple approximate method for predicting resonant vibration levels is the most appropriate. A number of examples and applications are described.     

目标落点的视觉测量方法研究

 针对传统视觉测量方法不能用于远距离和大场域目标测量的问题,提出了一种简单的视觉测量方法,可精确地测量远距离、大场域内目标落点的位置。利用简单的现场标校方法,使两相机的横向核平面水平且重合。在此基础上,根据视觉测量原理,建立了简化的落点坐标视觉测量模型。利用该模型,在250 m×350 m的测量区域内对遍布相机视场的44个目标点进行了视觉测量实验。实验数据显示:各点的综合相对测量误差小于0.3%,达到了较高的测量精度,完全适用于远距离、大视场的目标落点测量。     

An investigation of simple methods for assessing reverberation time

There is considerable interest in the development of a simple test for sound insulation between dwellings. The assessment of reverberation time is the most difficult part of the procedure to simplify. In this paper six alternative methods are described and evaluated. The first three require no electronic apparatus but are not accurate enough for general use. The fourth involves using sufficient absorbing material in the receiving room to effectively determine the RT. This approach appears worth further development. The fifth approach requires a source of known sound power and the final method employs a simple meter giving a direct reading of the decay time. The last two methods appear to be accurate enough for inclusion in a simplified test method but the simple meter seems to have some advantage.