Inherent peak compression of charged analytes in electrochromatography

This work resolves peak compression of charged analytes in CEC with strong cation‐exchange stationary phase particles. By combining electrochromatographic peak shape analysis with the results of numerical simulations and confocal laser scanning microscopy in the packed capillaries, we identify electrical field‐induced concentration polarization as the key physical phenomenon responsible for the inherent existence of local electrical field gradients on the scale of an individual support particle. Consequently, positive and negative field gradients exist between and inside the particles along the whole packing. Their intensity depends on the particles cation‐selectivity (governed by the particles volume charge density and the mobile phase ionic strength) and the applied field strength. The interplay of these local field gradients with the analytes retention (intraparticle adsorption) determines whether fronting, tailing, or spiked analyte peaks are observed, and it provides a mechanism by which strongly retained analytes can be eluted over long distances with little zone dispersion. Our analysis explains the “anomalous” peak compression effects with strong cation‐exchange particles, which have been reported more than a decade ago (Smith, N. W., Evans, M. B., Chromatographia 1995, 41, 197–203) and since then remained largely unresolved.     

The Limiting Behavior for Observations That Change with Time

Consider a system where units have random magnitude entering according to a homogeneous or nonhomogeneous Poisson process, while in the system, a unit's magnitude may change with time. In this paper, the authors obtain some results for the limiting behavior of the sum process of all unit magnitudes present in the system at time t.     

混合序列矩不等式和非参数估计

对p-混合、(?)-混合序列给出两个矩不等式,它们在加权和序列研究中比邵启满在[6]、[7]中给出的矩不等式更实用.作为应用,这里讨论非参数递归密度核估计的强收敛速度和非参数回归函数加权核估计的强相合性,获得较好结论.     

Strong Minimal Covers for Recursively Enumerable Degrees

We prove that there exists a nonzero recursively enumerable Turing degree possessing a strong minimal cover. Mathematics Subject Classification: 03D30.     

钠化合物洗提钨及混合洗提中共存反离子的加速效应

研究了在季胺Ⅰ型强碱性阴离子交换树脂上用ＮａＯＨ、ＮａＮＯ３、ＮａＣｌ和ＮＨ４Ｃｌ洗提及洗提后的吸附特性。给出了洗提曲线、穿透曲线和工作交换容量。采用ＮａＣｌ和ＮａＯＨ混合洗提的工艺，获得了钨浓度高而过剩洗提剂含量低的洗出液。为由洗出液蒸发结晶制取高纯Ｎａ２ＷＯ４·２Ｈ２Ｏ开辟了途径。混合洗提的宏观结果表明：由于反离子的存在，Ｃｌ－、ＯＨ－和在溶液相或交换剂中的扩散系数发生改变，→Ｃｌ－及→ＯＨ－的交换速度加快了。     

A survey of certain results on strong approximation by orthogonal series

This is a survey of results in a particular direction of the theory of strong approximation by orthogonal series, related mostly with author's contributions to the subject.     

非负整值随机变量序列的一类强偏差定理

设是在中取值的一列随机变量，其联合分布为是S上的一个分布，该文研究对数似然比与之间的若干极限关系，得到了一类用不等式表示的强极限定理（称之为强偏差定理），其偏差界依赖于样本点．证明中结合区间刻分法，提出了将母函数的工具应用于强极限定理研究的一种途径．     

Asymptotic Properties of a Nonparametric Regression Function Estimator with Randomly Truncated Data

In this paper, we define a new kernel estimator of the regression function under a left truncation model. We establish the pointwise and uniform strong consistency over a compact set and give a rate of convergence of the estimate. The pointwise asymptotic normality of the estimate is also given. Some simulations are given to show the asymptotic behavior of the estimate in different cases. The distribution function and the covariable’s density are also estimated.     

Strong convergence of estimators as ε n -minimisers of optimisation problemsof optimisation problems

In the paper we prove strong consistency of estimators as solution of optimisation problems. The approach of the paper covers non-identifiable models, and models for dependent samples. We provide statements about consistency of M-estimators in regression models with random and with non-random design. The research was partially supported by the Deutsche Forschungsgemeinschaft (project number 436TSE113/40) and by the Grant Agency of the Czech Republic under Grant 201/03/1027.     

Luminescence related processes in semiconductor nanocrystals —The strong confinement regime

This paper summarizes systematic studies on the luminescence from CdSe nanocrystals in the situation of strong zero-dimensional confinement. We discuss the role of surface and defect states, the origin of the photo-darkening and demonstrate by calorimetric adsorption measurements that the internal quantum efficiency is in the range of some 10%. The lifetimes of the intrinsic excitations are strongly size-dependent. While the radiative recombination (≈ 1 ns) is dominant for larger nanocrystals, we observe a dramatic increase of the non-radiative rate below 4 nm as a result of the reduced volume to surface ratio. The combination of ultra-fast and size-selective excitation allows us to observe a progression of sharp LO-phonon lines signifying the zero-dimensional character of the nanocrystals and providing information on the strength of the phonon coupling and the homogeneous width of the quantum-confined ground state.