Universality principle and the development of classical density functional theory

The universality principle of the free energy density functional and the ‘test particle' trick by Percus are combined to construct the approximate free energy density functional or its functional derivative. Information about the bulk fluid radial distribution function is integrated into the density functional approximation directly for the first time in the present methodology. The physical foundation of the present methodology also applies to the quantum density functional theory.     

纤维管内固相微萃取-原子荧光光度法测定水中痕量As(Ⅴ)

用聚丙烯纤维作为基体,利用高能电子辐照接枝制备了叔铵化纤维,并采用溴代乙烷季铵化得到季铵型离子交换纤维。将制备的季铵型离子交换纤维用于纤维固相微萃取方法中的吸附剂,与原子荧光光度法相结合,建立了一种简单、快速的测定溶液中痕量As(Ⅴ)的方法。研究了溶液pH、流速、溶液浓度对吸附的影响,并对洗脱剂的种类、洗脱剂的流速和体积进行了优化。在最佳反应条件下,As(Ⅴ)的定量限为0.1μg/L,富集因子为50,相对标准偏差为4.5%(n=6)。该方法可测定复杂基质中痕量As(Ⅴ)。