Error estimates of finite volume element method for the pollution in groundwater flow

In this article, we study the finite volume element methods for numerical solution of the pollution in groundwater flow in a two‐dimensional convex polygonal domain. These type flow are uniform transport in a fully saturated incompressible porous media, which may be anisotropic with respect to hydraulic conductivity, but features a direction independent of dispersivity. A fully finite volume scheme is analyzed in this article. The discretization is defined via a planar mesh consisting of piecewise triangles. Optimal order error estimates in H¹ and L² norms are obtained. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009     

Solution and its application of transient stream/groundwater model subjected to time-dependent vertical seepage

Based on the first linearized Boussinesq equation,the analytical solution of the transient groundwater model,which is used for describing phreatic flow in a semi- infinite aquifer bounded by a linear stream and subjected to time-dependent vertical seepage,is derived out by Laplace transform and the convolution integral.According to the mathematical characteristics of the solution,different methods for estimating aquifer parameters are constructed to satisfy different hydrological conditions.Then,the equation for estimating water exchange between stream and aquifer is proposed,and a recursion equation or estimating the intensity of phreatic evaporation is also proposed.A phreatic aquifer stream system located in Hualbei Plain,Anhui Province,China,is taken as an example to demonstrate the estimation process of the methods stated herein.     

电感耦合等离子体原子发射光谱法(ICP-OES)测定地下水中多种元素

应用电感耦合等离子体原子发射光谱法(ICP-OES)测定地下水中钾、钠、钙、镁、铁、锰元素的含量,使用分光光度法测定氟的含量,测定的相对标准偏差为0.7%~2.8%,加标回收率为92.1%~105.2%。结果表明,大部分地区地下水中钠和氟化物的含量均偏高,常量与微量元素的组成含量差别不大。     

液相色谱-原子荧光光谱联用法测定地下水中的三价砷和五价砷

建立了一种利用液相色谱-原子荧光光谱联用法测定地下水中三价砷和五价砷含量的方法。流动相为磷酸二氢钾和磷酸氢二钠,流速1.0mL/min,方法的标准曲线线性相关性好,进样后在10min内分离、测定完毕,操作自动化程度高,重现性好,方法准确可靠,检出限低(As~(3+)、As~(5+)都是0.02μg/L),可同时测定地下水中As~(3+)、As~(5+)的含量。     

基于SAO-VMD-FFT的激光诱导荧光光谱信号信噪比提升方法

针对基于激光诱导荧光光谱法(LIFs)的便携式场地地下水检测技术装备在原位检测地下水中典型重金属时,光传感信号含噪声严重,影响后续定量分析准确度的问题,提出了一种雪消融优化器(SAO)寻优算法优化的变分模态分解(VMD)结合快速傅里叶变换(FFT)的LIFs光传感信号信噪比提升算法。利用SAO算法对VMD分解关键参数分解模态个数K和惩罚因子α进行优化,实现含噪信号的自适应最佳VMD分解,得到一系列本征模态分量。进一步结合FFT算法寻找频率突变点从而筛选出相关模态。累计相关模态得到信噪比提升后的信号。通过仿真和实测信号分析,结果表明与EMD、WTD和S-G等常用算法相比,本文算法能更好地去除LIFs信号中的噪声分量,保留有用信息,验证了该方法的可行性和有效性,可为后续利用LIFs传感信号原位定量分析地下水中重金属元素含量提供支持。