A Calculation of the Electron Temperature of Complex Plasma of Noble Gases Mixture in CCRF Discharge

In this paper the results of studying of the electron temperature of buffer and complex plasmas in mixtures of noble gases (helium + argon) in capacitively coupled radiofrequency (CCRF) discharge are presented. The optical properties of dusty plasma in argon, helium and their mixtures have been studied using optical diagnostic methods. Based on spectral lines of plasma forming gases, the dependence of the electron temperature on gas pressure and discharge power has been determined. The axial distribution of electron temperature in the interelectrode gap has been measured. Measurements have been made using an RF compensated electric probe. The comparison of the experimental results shows that admixture of a small amount of argon to helium leads to a decrease in the electron temperature of buffer plasma. The presence of dust particles in the plasma causes an increase in the electron temperature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

基于改进高斯混合模型的运动目标检测与跟踪算法

针对传统高斯模型存在的不足,为了搞高运动目标跟踪精度,提出一种基于改进高斯混合模型的目标检测与跟踪算法。首先提取目标特征建立目标分类器,并将目标从前景是标记出来;然后通过多目标跟踪将目标为多种运动模式;最后采用高斯混合模型对跟踪与分类的结果进行融合,获得最终目标的位置。结果表明,本文方法不仅提高了目标检测与跟踪精度,而且可高斯模型以较好的满足目标跟踪的实时性要求。     

Mixture models for two-dimensional baseline correction,applied to artifact elimination in time-resolved spectroscopy

Baseline correction and artifact removal are important pre-processing steps in analytical chemistry. We propose a correction algorithm using a mixture model in combination with penalized regression. The model is an extension of a method recently introduced for baseline estimation in the case of one-dimensional data. The data are modeled as a smooth surface using tensor product P-splines. The weights of the P-splines regression model are computed from a mixture model where a datapoint is either allocated to the noise around the baseline, or to the artifact component. The method is broadly applicable for anisotropic smoothing of two-way data such as two-dimensional gel electrophoresis and two-dimensional chromatography data. We focus here on the application of the approach in femtosecond time-resolved spectroscopy, to eliminate strong artifact signals from the solvent.     

Mass spectrometry-based metabolomics applied to the chemical safety of food

Mass spectrometry (MS)-based metabolomics is emerging as an important field of research in many scientific areas, including chemical safety of food. A particular strength of this approach is its potential to reveal some physiological effects induced by complex mixtures of chemicals present at trace concentrations. The limitations of other analytical approaches currently employed to detect low-dose and mixture effects of chemicals make detection very problematic. Besides this basic technical challenge, numerous analytical choices have to be made at each step of a metabolomics study, and each step can have a direct impact on the final results obtained and their interpretation (i.e. sample preparation, sample introduction, ionization, signal acquisition, data processing, and data analysis). As the application of metabolomics to chemical analysis of food is still in its infancy, no consensus has yet been reached on defining many of these important parameters. In this context, the aim of the present study is to review all these aspects of MS-based approaches to metabolomics, and to give a comprehensive, critical overview of the current state of the art, possible pitfalls, and future challenges and trends linked to this emerging field.     

基于逆检索-非负最小二乘法的拉曼混合物分析方法研究

拉曼光谱因它可以提供非常丰富的结构信息而被看作是一项"指纹"技术,因此拉曼光谱可以被用作物质的定性识别。并且拉曼光谱具有制样简单,不破坏样品,在几乎所有的环境下都可以采集。通常认为拉曼光谱只能提供纯物质的结构信息,故利用拉曼光谱分析混合物的成分是有难度的。在便携式拉曼光谱仪、光谱数据库和化学计量学的基础上,开发了一种快速的混合物鉴别方法。根据基于小波域的自动精确峰值检测拉曼光谱的特点,对经典的逆搜索过程进行了改进。匹配质量可以用计算混合物和数据库中相减光谱中的负比率(按最小比例计算反向匹配峰的比值),提出一种基于改进的逆搜索和非负最小二乘法(Reverse searching and non-negative least squares,RSearch-NNLS),用于混合物分析。方法包括以下步骤:1)通过Whittaker平滑、ariPLS基线校正以及连续小波变换建立纯物质的拉曼光谱库;2)通过逆检索法对采集到的混合物拉曼光谱进行定性分析;3)根据第2步的结果,使用非负最小二乘法对候选化合物进行比例估算。方法是一种鉴别混合物的方法,具有一定的应用前景。