精油中挥发性成分GC/FTIR与GC/MS联合分析

采用同时蒸馏萃取(SDE)法获得了香紫苏(Salvia sclarea L.)精油,利用气相色谱/傅里叶变换红外光谱联用(GC/FTIR)和气相色谱/质谱联用(GC/MS)相结合的手段,对其挥发成分进行了定性和定量分析,着重讨论了GC/FTIR在精油分析中的应用研究。通过不同波数官能团(Gram-Schmidt)重建红外光谱图、红外光谱差谱技术及质谱等相互验证的方法,大大提高了香紫苏油挥发成分的定性分析准确性。     

电感耦合等离子体质谱法测定高纯稀土样品中多种非稀土杂质

研究建立了高纯稀土样品中24种非稀土杂质元素的电感耦合等离子质谱法(ICP-MS)测定方法。考察了几类典型金属样品分析中的基体效应,引入内标元素铟,有效补偿了基体效应引起的非质谱干扰。对几种在分析过程中存在质谱干扰的样品,通过分离基体进行测定。方法测定下限为1.8~390 ng.g-1,RSD为2.9%~5.4%,加标回收率为92%~107%。     

Numerical solution of the singularly perturbed problem for the hyperbolic equation with initial jump

In this paper we consider the initial-boundary value problem for a second order hyperbolic equation with initial jump. The bounds on the derivatives of the exact solution are given. Then a difference scheme is constructed on a non-uniform grid. Finally, uniform convergence of the difference solution is proved in the sense of the discrete energy norm.     

An exponentially fitted difference scheme for the hyperbolic-hyperbolic singularly perturbed initial-boundary value problem

In this paper we discuss,an initial-boundary value problem of hyperbolic type with firstderivative with respect to x.The asymptotic solution is constructed and its uniform validityis proved under weader compatibility conditions.Then we develop an exponentially fitteddifference scheme and establish discrete energy inequality.Finally,we prove that thesolution of difference problem uniformly converges to the solution of the original problem.     

我是怎样創造快速乘除計算图的

我是一个统计员,是一个普普通通的青年,只在高中读过一年书。但在党和人民的大力支持下,经过四年多时间的研究,终于创造了快速乘除计算图。这种图的特点是: (1) 速度快:算四,五位除法,可比手摇计算机快一倍以上;比珠算快三,四倍。 (2) 简单易学:十几分钟就可学会。 (3) 比计算尺准确:用大型图能算五位乘除,误差小于万分之一。 (4) 成本低:每套只要几角或一两元。有些图适合于财经部门,还有些小型图适合于工