层结流体中具有β效应与地形效应的强迫Rossby孤立波

层结流体中,从绝热位涡的扰动方程出发采用摄动方法和时空伸长变换推导了具有β效应和地形效应的强迫Rossby孤立波方程,得到孤立Rossby波振幅的演变满足带有地形强迫的非齐次mKdV方程的结论. 通过分析孤立Rossby波振幅的演变,即使基本气流没有切变,仍可能激发出Rossby孤立波.指出了科氏力效应、地形效应以及Vaisala-Brunt频率都是诱导Rossby孤立波产生的重要因素,说明了在地形强迫效应和非线性作用相平衡的假定下,Rossby孤立波振幅的演变满足非齐次的mKdV方程.讨论 关键词： 非齐次mKdV方程 β效应')" href="#">β效应 地形 Vaisala-Brunt 频率     

切变纬向流中β效应与缓变地形Rossby波

正压流体中,从有外源的准地转位涡方程出发,采用摄动方法和时空伸长变换推导了具有β效应、缓变地形和外源的Rossby孤立波方程,得到Rossby波振幅满足带有缓变地形与外源强迫的非齐次mKdV-Burgers方程的结论.通过分析孤立Rossby波振幅的演变,指出了β效应、地形效应以及外源都是诱导Rossby孤立波产生的重要因素;说明了在缓变地形强迫效应和非线性作用相平衡的假定下,Rossby孤立波振幅的演变满足非齐次mKdV-Burgers方程;给出在切变基本气流下缓变地形和正压流体中Rossby波的相互作用关系.     

层结流体中在热外源和β效应地形效应作用下的非线性Rossby孤立波和非齐次Schrödinger方程

在层结流体中, 从带有地形、热外源耗散的下边界条件以及带有热外源的准地转位涡方程开始, 使用小参数展开方法和多尺度时空伸长变换推导出了具有热外源、β效应和地形效应的强迫Rossby孤立波方程, 得到孤立Rossby振幅满足的带有地形与热外源的非齐次非线性的Schrödinger方程. 通过分析Rossby孤立波振幅的变化, 指出了热外源、β效应和地形效应都是诱导Rossby孤立波产生的重要因素, 给出了切变基本流下地形、热外源和层结流体中Rossby的相互作用.     

强迫耗散与β效应地形效应作用下的非线性Rossby波包

正压流体中,从有外源的准地转位涡方程出发采用摄动方法和时空伸长变换推导了具有β效应、地形效应和外源的强迫Rossby孤立波包方程,得到孤立Rossby波振幅的演变满足带有地形与外源强迫的非齐次非线性Schrödinger方程的结论. 通过分析孤立Rossby波包振幅的演变,指出了β效应、地形效应以及外源都是诱导Rossby孤立波产生的重要因素,说明了在地形强迫效应和非线性作用相平衡的假定下,Rossby孤立波包振幅的演变满足非齐次非线性Schrödinger 关键词： Rossby波包 β效应')" href="#">β效应 地形 Schrödinger方程     

切变基本纬向流中β效应的赤道Rossby孤立波包

从描写赤道Rossby 波的正压大气位涡方程出发,采用多重尺度摄动方法推导出在切变基本纬向流中具有β效应的非线性赤道Rossby波包演变满足非线性Schrdinger方程,并得到单个包络孤立子波解,分析了基本切变流,β效应对非线性赤道Rossby波的影响. 关键词： 赤道Rossby波 β效应 非线性Schrö dinger方程 包络孤立子     

缓变下垫面和耗散作用的非线性Rossby波

从准地转位涡方程出发,采用摄动方法和时空伸长变换推导了在缓变下垫面和耗散共同作用的Rossby代数孤立波方程,得到Rossby波振幅满足带有缓变下垫面的非齐次Benjamin-Davis-Ono-Burgers(BDOBurgers)方程的结论.指出地形效应和耗散是诱导非线性Rossby波产生的重要因素,说明了在缓变下垫面强迫效应和非线性作用相平衡的假定下,Rossby孤立波振幅的演变满足非齐次BDO-Burgers方程,给出在切变基本气流下缓变下垫面和正压流体中Rossby波的相互作用.     

缓变地形下Rossby波振幅演变满足的带有强迫项的KdV方程

运用非线性方法与摄动法,讨论了当地形随时间缓变时Rossby波振幅的演变问题.从均值流体准地转涡度方程推导,得到Rossby波振幅演变满足带有强迫项的KdV方程的结论,而地形随时间的缓慢变化诱导了该方程的强迫项. 关键词： 非线性Rossby波 带有强迫项的KdV方程 摄动法 缓变地形     

非静水压条件下铁从α到ε结构相变的第一性原理计算

采用基于密度泛函理论的平面波赝势方法,研究了三轴加载的非静水压力和静水压力对铁从体心立方结构（bcc,α相）到六角密排结构（hcp,ε相）相变压力和磁性的影响,结果发现：在0—18 GPa压力范围内,相对静水压力条件,随着压力的升高,bcc结构的原子磁矩在非静水压力下降低得更快;在非静水压力下,相变更容易发生,相变压力随着非静水压力程度的增加而降低;并且对非静水压力对相变压力影响的物理机理进行了讨论. 关键词： 相变 非静水压力 第一性原理 铁     

两个非线性发展方程的双向孤波解与孤子解

采用分步确定拟解的原则, 对齐次平衡法求非线性发展方程孤子解的关键步骤作了进一步改 进. 以广义Boussinesq方程和bidirectional Kaup-Kupershmidt方程为应用实例, 说明使用 该方法可有效避免“中间表达式膨胀”的问题, 除获得标准Hirota形式的孤子解外, 还能获 得其他形式的孤子解. 关键词： 齐次平衡法 孤子解 孤波解 广义Boussinesq方程 bidirectional Kaup-Kupershmi dt方程     

核子-核子碰撞截面对同位素标度参数α的介质效应

核子能量在40—60MeV能区范围,对在两对重离子中心碰撞系统⁴⁰Ca+⁴⁸Ca和⁶⁰Ca+⁴⁸Ca以及¹¹²Sn+¹¹²Sn和¹²⁴Sn+¹²⁴Sn 的反应中就同位素标度参数α对于核子-核子碰撞截面σ^med_NN(α_m)的介质 关键词： 同位素标度行为 介质效应 核子-核子碰撞截面 重离子碰撞     

Forced solitary Rossby waves under the influence of slowly varying topography with time

By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg-de Vries (KdV)-Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influence of dissipation and slowly varying topography with time. The analysis indicates that dissipation and slowly varying topography with time are important factors in causing variation in the mass and energy of solitary waves.     

Forced solitary Rossby waves under the influence of slowly varying topography with time

By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg-de Vries (KdV)-Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influence of dissipation and slowly varying topography with time. The analysis indicates that dissipation and slowly varying topography with time are important factors in causing variation in the mass and energy of solitary waves.     

Modified KdV equation for solitary Rossby waves with β effect in barotropic fluids

This paper uses the weakly nonlinear method and perturbation method to deal with the quasi-geostrophic vorticity equation, and the modified Korteweg-de Vries(mKdV) equations describing the evolution of the amplitude of solitary Rossby waves as the change of Rossby parameter β(y) with latitude y is obtained.     

Algebraic Rossby Solitary Waves Excited by Non-Stationary External Source

The paper deals with the effects of non-stationary external source forcing and dissipation on algebraic Rossby solitary waves.From quasi-geostrophic potential vorticity equation,basing on the multiple-scale method,an inhomogeneous Korteweg-de Vries-Benjamin-Ono-Burgers(KdV-B-O-Burgers) equation is obtained.This equation has not been previously derived for Rossby waves.By analysis and calculation,four conservation laws associated with the above equation are first obtained.With the help of pseudo-spectral method,the waterfall plots are obtained and the evolutional characters of algebraic Rossby solitary waves are studied.The results show that non-stationary external source and dissipation have great effect on the generation and evolution of algebraic solitary Rossby waves.     

Algebraic Rossby Solitary Waves Excited by Non-Stationary External Source

The paper deals with the effects of non-stationary external source forcing and dissipation on algebraic Rossby solitary waves. From quasi-geostrophic potential vorticity equation, basing on the multiple-scale method, an inhomogeneous Korteweg-de Vries-Benjamin-Ono-Burgers (KdV-B-O-Burgers) equation is obtained. This equation has not been previously derived for Rossby waves. By analysis and calculation, four conservation laws associated with the above equation are first obtained. With the help of pseudo-spectral method, the waterfall plots are obtained and the evolutional characters of algebraic Rossby solitary waves are studied. The results show that non-stationary external source and dissipation have great effect on the generation and evolution of algebraic solitary Rossby waves.     

正压大气环流中的曲面周期波和孤波

大尺度正压大气环流的波动特征对理解气候变化具有重要的意义,而非线性浅水波方程组是描述大尺度正压大气环流的原始控制方程.本文对线性方程的复变函数解,通过二次适当的移植,求得浅水波方程组的发展方程的扰动位势的实变函数解,该实变函数解析解由基流项和波动项两部分组成.其中基流由波数、波速、β效应、变形半径和时间的任意函数共同决定;波动项与β效应有关.分析表明,在大尺度正压大气环流中扰动位势存在曲面的周期波和孤波的现象,周期波与孤波相互调制而呈现不稳定性;当多个周期孤波同时出现时,则彼此独立传播;扰动位势波动项中的时间任意函数对曲面周期孤波的波幅有调制作用,可控制波的产生、发展和消失.所得结果对研究大气波动现象和气候变化具有一定的理论参考价值.     

A(2+1)-dimensional nonlinear model for Rossby waves in stratified fluids and its solitary solution

In this paper,we investigate a(2+1)-dimensional nonlinear equation model for Rossby waves in stratified fluids.We derive a forced Zakharov–Kuznetsov(ZK)–Burgers equation from the quasigeostrophic potential vorticity equation with dissipation and topography under the generalized beta effect,and by utilizing temporal and spatial multiple scale transform and the perturbation expansion method.Through the analysis of this model,it is found that the generalized beta effect and basic topography can induce nonlinear waves,and slowly varying topography is an external impact factor for Rossby waves.Additionally,the conservation laws for the mass and energy of solitary waves are analyzed.Eventually,the solitary wave solutions of the forced ZK–Burgers equation are obtained by the simplest equation method as well as the new modified ansatz method.Based on the solitary wave solutions obtained,we discuss the effects of dissipation and slowly varying topography on Rossby solitary waves.