高效液相色谱—核磁共振联用技术

本文简要地综述了高效液相色谱与核磁共振联用技术,并列举了该技术在药物、天然产物以及异构体研究中的应用。     

短波近红外光谱的盐酸环丙沙星粉末药品的定量分析

利用漫反射法获得环丙沙星短波近红外光谱(700-1100nm),采用化学计量学中的偏最小二乘法(PLS),选取不同的波长范围及不同的光谱预处理方法(一阶导数和和二阶导数)对光谱进行信息提取和分析,对盐酸环丙沙星粉末药品进行了无损非破坏定量分析,以样品中盐酸环丙沙星为活性成分建立了最佳的数学校正模型。讨论了主成分数对PLS模型定量预测能力的影响,并做了比较。     

有机同系物的一个同系线性规律

对有机同系物的同系线性规律进行了探讨,提出了有机同系物的一种同系线性规律,其表达式为,并用有机共轭体系和双向共轭同系物的光电子能谱数据对该线性规律进行了验证。     

运用表面光电压技术对半导体表面光电特性的研究

对运用表面光电压技术(SPS)对半导体材料光电性质的研究进行了综述,系统阐述了表面光电压谱(SPS)和场诱导表面光电压谱(FISPS)在测定半导体类型、表面态及其能级位置、表面电荷分布、半导体的能带隙等方面所表现出的优越性质.研究了半导体能带隙所表现出的特有性质.     

Integrated marked Poisson processes with application to image correlation spectroscopy

Image correlation spectroscopy (ICS) is an experimental technique used in the study of cell tissue, specifically to obtain information about protein aggregates. This paper discusses a filtered Poisson process model of ICS, and uses this to obtain the sampling distribution of an estimator of interest, using spectral methods. Integrals of third- and fourth-order spectra are involved, and methods proposed in the literature are studied numerically. They are found to be infeasible methods, requiring months of computing time. An alternative method is proposed and is illustrated on some actual ICS experiments. A novel feature in this study is the use of a SIMD-class parallel computer, a MasPar MP-2 machine, to obtain some statistical properties of the estimation method.     

Using unlabelled data to update classification rules with applications in food authenticity studies

Summary.  An authentic food is one that is what it purports to be. Food processors and consumers need to be assured that, when they pay for a specific product or ingredient, they are receiving exactly what they pay for. Classification methods are an important tool in food authenticity studies where they are used to assign food samples of unknown type to known types. A classification method is developed where the classification rule is estimated by using both the labelled and the unlabelled data, in contrast with many classical methods which use only the labelled data for estimation. This methodology models the data as arising from a Gaussian mixture model with parsimonious covariance structure, as is done in model-based clustering. A missing data formulation of the mixture model is used and the models are fitted by using the EM and classification EM algorithms. The methods are applied to the analysis of spectra of food-stuffs recorded over the visible and near infra-red wavelength range in food authenticity studies. A comparison of the performance of model-based discriminant analysis and the method of classification proposed is given. The classification method proposed is shown to yield very good misclassification rates. The correct classification rate was observed to be as much as 15% higher than the correct classification rate for model-based discriminant analysis.     

用累积法确定光子相关光谱测量中的超细颗粒粒度

本文扼要介绍了应用光子相关光谱法(PCS)确定超细颗粒粒度的基本理论,详细讨论了PCS测量中用累积法确定超细颗粒粒度的基本方法,分析了这一方法的特点和适应性。并给出了用Pearson I型分布模拟数据的考核计算和对聚苯乙烯标准粒子实测结果。     

火焰原子吸收分析中表面活性剂对铬吸收信号的增敏作用及机理研究

通过研究火焰原子吸收分析中表面活性剂对铬吸收信号的增敏作用 ,建立表面活性剂的增敏作用机理模型     

GeH2分子振转光谱常数的从头算研究

用B3LYP,B3PW91和MP2方法分别在cc-pVTZ和cc-pVQZ基组水平下计算了GeH2分子的光谱常数,将计算得到的平衡几何结构、基态转动常数、基频和谐频、部分四次离心畸变常数和振转相互作用常数与相应的实验数据或理论值进行了比较,并对其它的四次离心畸变常数、六次离心畸变常数、平衡转动常数及非谐性常数进行了预测.结果显示,由密度泛函理论计算的数据与实验值吻合得很好,因此,用密度泛函理论预测GeH2分子的光谱常数是可靠的.     

光子相关光谱法测量超细颗粒的理论研究

光子相关光谱学(PCS)是一项近年来取得较大进展的新应用技术,该技术利用悬浮于介质中的散射体的布朗运动所引起的散射光强涨落现象,能测量粒径范围为3nm～3μm的超细颗粒。本文详述了PCS测粒法的基本理论,综述了各种预测颗粒粒径分布的数据处理方法,并提出了对PCS进一步研究的若干问题。