显生宙以来海水组分变化对海相钾盐蒸发岩的制约作用

过去550Ma大洋中脊热液流体对海水主要组分的演化起重要作用,地幔对流和板块运动引起两个显生宙超级大循环,使海水组分发生长期连续变化,并决定了不同时期的蒸发岩矿物组合。通过海相蒸发岩矿物学特征、海相蒸发岩底部石盐Br含量特征、海相蒸发岩基底石盐流体包裹体卤水组分特征等的详尽阐述,证实显生宙以来海水组分经历了"文石海"和"方解石海"的交替振荡模式;Mg/Ca值的变化造成"文石海"以MgSO4型蒸发岩为主,"方解石海"以KCl型蒸发岩为主;Mg/Ca值的变化主要受海底扩张速率、大洋中脊热液流体循环、碳酸盐岩盐沉积循环等因素影响。海水组分变化特征控制着海相钾盐蒸发岩的形成类型,亦为海相钾盐蒸发岩的物源与成因提供更多的科学依据。

海水中动态污垢组成及影响因素的实验研究

海水冷却水有诸多优势,但是存在结垢的弊端。本文搭建了一套海水动态结垢实验装置;通过污垢热阻的变化来表征加热管外表面污垢结垢量的变化,并使用X射线衍射(X-ray Diffraction,XRD)、扫描电镜(Scanning Electron Microscope,SEM)和X射线能谱(Energy Dispersive X-Ray,EDX)法对海水动态污垢进行物相与形态分析;通过实验研究分析热流密度、Re数、进口温度和不同材料对海水结垢的影响。结果发现,动态海水在不锈钢表面形成污垢的主要成分是水合氢氧化镁铝;最长诱导期出现的工况是进口温度为50℃,Re数为1,600,热流密度为1×10~5 W/m^2;100 h内1×10~5 W/m^2热流密度下的平均热阻是0.5×10~5 W/m^2的1.93倍;Re数为6,283的海水污垢热阻大于Re数为1,600的海水污垢热阻;随着海水流体温度升高,结垢量下降;铜管的抗垢性能优于不锈钢管。

A DISCONTINUOUS GALERKIN METHOD COMBINED WITH MIXED FINITE ELEMENT FOR SEAWATER INTRUSION PROBLEM

Seawater intrusion problem is considered in this paper.Its mathematical model is anonlinear coupled system of partial differential equations with initial boundary problem.It consistsof the water head equation and the salt concentration equation.A combined method is developedto approximate the water head equation by mixed finite element method and concentration equationby discontinuous Galerkin method.The scheme is continuous in time and optimal order estimates inH^1-norm and L^2-norm are derived for the errors.