含线性阻尼的2D非自治g-Navier-Stokes方程的拉回吸引子

讨论了无界区域上含线性阻尼的2D非自治g-Navier-Stokes方程的拉回吸引子,通过验证共圈的拉回公.吸收集的存在性和拉回公一渐近紧性,证明了含线性阻尼的2D非自治g-Navier-Stokes方程的拉回吸引子的存在性,并给出了拉回吸引子的Fractal维数估计.     

Adaptive mixed least squares Galerkin/Petrov finite element method for stationary conduction convection problems

An adaptive mixed least squares Galerkin/Petrov finite element method (FEM) is developed for stationary conduction convection problems. The mixed least squares Galerkin/Petrov FEM is consistent and stable for any combination of discrete velocity and pressure spaces without requiring the Babuska-Brezzi stability condition. Using the general theory of Verfürth, the posteriori error estimates of the residual type are derived. Finally, numerical tests are presented to illustrate the effectiveness of the method.     

时滞惯性流形及近似时滞惯性流形族

时滞惯性流形是对耗散系统惯性流形、近似惯性流形的最新发展,它基于对 大小涡分量间相互作用更细致的观察,即改变了惯性流形和近似惯性流形方法中大小 涡分量间相互作用为瞬时行为的隐含假定,而认为这种作用与系统的历史相关的．本 文结出了一类耗散系统时滞惯性流形的存在性证明,由于其存在性不需要“谱间隔条 件”保证,因而时滞惯性流形是广泛存在的．随后我们引出了一类离散的时滞惯性流 形,并在此基础上构造了一种近似时滞惯性流形族,分别给出了它们近似时滞惯性流 形的误差估计,结果显示这种新方法为构造稳定和高精度的算法提供了可能．     

Local and parallel finite element algorithms for time-dependent convection-diffusion equations

Local and parallel finite element algorithms based on two-grid discretization for the time-dependent convection-diffusion equations are presented. These algorithms are motivated by the observation that, for a solution to the convection-diffusion problem, low frequency components can be approximated well by a relatively coarse grid and high frequency components can be computed on a fine grid by some local and parallel proce- dures. Hence, these local and parallel algorithms only involve one small original problem on the coarse mesh and some correction problems on the local fine grid. One technical tool for the analysis is the local a priori estimates that are also obtained. Some numerical examples are given to support our theoretical analvsis.     

Pullback attractor of 2D non-autonomous <Emphasis Type="Italic">g</Emphasis>-Navier-Stokes equations on some bounded domains

The existence of the pullback attractor for the 2D non-autonomous g-Navier- Stokes equations on some bounded domains is investigated under the general assumptions of pullback asymptotic compactness. A new method to prove the existence of the pullback attractor for the 2D g-Navier-Stokes eauations is given.     

Pullback attractor of 2D nonautonomous <Emphasis Type="Italic">g</Emphasis>-Navier-Stokes equations with linear dampness

The pullback attractors for the 2D nonautonomous g-Navier-Stokes equations with linear dampness are investigated on some unbounded domains. The existence of the pullback attractors is proved by verifying the existence of pullback D-absorbing sets with cocycle and obtaining the pullback D-asymptotic compactness. Furthermore, the estimation of the fractal dimensions for the 2D g-Navier-Stokes equations is given.     

非定常对流扩散方程的局部和并行有限元算法

对基于两重网格的非定常对流扩散方程的局部和并行有限元算法进行了研究.算法的理论依据是两重网格的思想,解的低频分量可以用一个整体的粗网格空间来逼近,高频分量可以用局部和并行的细网格空间来逼近.因此,这种局部和并行算法仅仅涉及一个粗网格上的整体逼近和细网格上的局部校正.得到了算法的误差估计,一些数值例子验证了算法的有效性.     

GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS

1. IntroductionIn the numerical simulation of the Navier-Stokes equations one encounters three seriousdifficulties in the case of large Reynolds numbers f the treatment of the incomPressibility con-dition divu = 0, the treatment of the noIilinear terms and the large time integration. For thetreatment of the incoInPressibility condition, one use the penalty method in the case of finiteelemellts [1--2l and for the treatmen of the noulinar terms and the large tfor integration, oneuse the nonlin…     

水相终止-溶剂萃取/气相色谱法分析氢氧化锆对VX的消毒率

建立了水相终止－溶剂萃取/气相色谱/火焰光度检测法（GC/FPD）测定氢氧化锆粉末对维埃克斯（VX）消毒率的分析方法,以保留时间定性分析,内标法定量。对液－固消毒样品的前处理方法进行了优化,考察了萃取剂、萃取方式、终止剂和静置时间对氢氧化锆消毒VX回收率的影响,发现样品采用10 mL 0.05 mol/L硼砂水溶液终止、50 mL二氯甲烷萃取、振荡20 s、静置10 min的萃取效果最好,回收率为87.8%～90.3%,相对标准偏差（RSD）不高于1.2%。优化条件下,在9.7～388.0 μg/mL线性范围内呈现良好的线性关系,相关系数（r2）为0.996 9,方法检出限（LOD）为0.05 μg/mL,定量下限（LOQ）为0.15 μg/mL。VX的消毒率随反应时间的变化关系满足拟一级动力学过程,反应速率常数（k）为0.019 2 min－1。该方法前处理简单、快速、安全,灵敏度和准确度高,可为两性氢氧化物类物质水解消毒反应的评价提供方法参考。