排序方式: 共有38条查询结果,搜索用时 15 毫秒
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Christina Ranninger Lukas E. Schmidt Marc Rurik Alice Limonciel Paul Jennings Oliver Kohlbacher Christian G. Huber 《Analytica chimica acta》2016
Untargeted metabolomics aims at obtaining quantitative information on the highest possible number of low-molecular biomolecules present in a biological sample. Rather small changes in mass spectrometric spectrum acquisition parameters may have a significant influence on the detectabilities of metabolites in untargeted global-scale studies by means of high-performance liquid chromatography-mass spectrometry (HPLC-MS). Employing whole cell lysates of human renal proximal tubule cells, we present a systematic global-scale study of the influence of mass spectrometric scan parameters and post-acquisition data treatment on the number and intensity of metabolites detectable in whole cell lysates. 相似文献
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《Analytical letters》2012,45(4):289-292
Abstract Magnetically scanned sector mass spectrometers yield excellent spectra, covering a wide mass range. The spectral display is most reproducible if the magnet is cycled continuously in order to establish a constant hysteresis history. We have adapted a single sweep spectrometer to continuous cycling. A simple and flexible control initiates and times the magnetic up- and down-sweep, erases and triggers a storage oscilloscope, advances and arrests the photographic recording chart and actuates an event marker on the recorder of the associated gas chromatograph. 相似文献
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In this article, waiting time distributions of compound patterns are considered in terms of the generating function of the
numbers of occurrences of the compound patterns. Formulae for the evaluation of the generating functions of waiting time are
given, which are very effective computational tools. We provide several viewpoints on waiting time problems associated with
compound patterns and develop a general workable framework for the study of the corresponding distributions. The general theory
is employed for the investigation of some examples in order to illustrate how the distributions of waiting time can be derived
through our theoretical results.
This research was partially supported by the ISM Cooperative Research Program (2006-ISM·CRP-2007). 相似文献
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C.E. Priebe 《Discrete Mathematics》2008,308(10):2034-2037
A scan statistic methodology for detecting anomalies has been developed for application to graphs, where “anomalies” are equated with vertices that exhibit distinctive local connectivity properties. We present an “anomaly graph” construction that illustrates the capabilities of these scan statistics via the behaviour of their associated locality statistics on our anomaly graphs. 相似文献
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钢中残量元素As,Sn,Sb的X射线荧光光谱分析 总被引:1,自引:0,他引:1
本文介绍了用日本理学3530XRF光谱仪扫描道测定钢中痕量元素As、Sn、Sb。由于短波强大的背景破坏了检测线的线性,通过用DATAFLEX 181B背景扣除的数据处理,消除了这些影响,成功地校准了曲线。方法简单;快速;XRFS结果与化学分析一致,该法已用于炼钢的过程控制和原材料分析。 相似文献
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A. Baddeley J. Møller A. G. Pakes 《Annals of the Institute of Statistical Mathematics》2008,60(3):627-649
For any point process in that has a Papangelou conditional intensity λ, we define a random measure of ‘innovations’ which has mean zero. When the
point process model parameters are estimated from data, there is an analogous random measure of ‘residuals’. We analyse properties
of the innovations and residuals, including first and second moments, conditional independence, a martingale property, and
lack of correlation. Some large sample asymptotics are studied. We derive the marginal distribution of smoothed residuals
by solving a distributional equivalence. 相似文献
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In this paper, we propose a test to distinguish between data with cluster pattern where the variables are dependent in a self-exciting fashion versus independently identically distributed random variables. We also developed asymptotic distribution of the test statistic with closed-form covariance structure. Comparisons with scan statistics are discussed in the context of simulated earthquake data. Applications to two data sets are discussed. 相似文献
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The limit behaviour of scan statistics in a form of maxima of moving sum processes with changing window size for detecting a transient change is studied. Approximate critical values obtained from tail behaviour of the limit variables that are maxima of some locally homogeneous Gaussian fields are compared with critical values obtained by simulation. 相似文献
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Dissolved oxygen (DO) is an essential indicator in chemical, biological and biochemical processes and needs to be rapidly measured in many cases. In this work, a rapid, sensitive and simple electrochemical method, first derivative linear sweep voltammetry (FD-LSV), was established for the determination of DO. The peak height of FD-LSV was found to be influenced by scan rate and microelectrode surface area. An empirical formula was proposed to describe the relationship between the FD-LSV peak height and the influencing factors. Compared with other electrochemical methods for DO determination, the FD-LSV method needed lesser time and was more accurate. This method was successfully applied for the determination of the DO levels of various environmental water samples. 相似文献