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981.
Lukas Vaclavik 《Talanta》2010,82(5):1950-1957
Direct analysis in real time (DART) ionization coupled to an (ultra)high resolution mass spectrometer based on orbitrap technology (orbitrapMS) was used for rapid quantitative analysis of multiple mycotoxins isolated from wheat and maize by modified QuEChERS procedure. After initial evaluation of ionization efficiencies for major groups of mycotoxins achievable with DART technology, sample preparation procedure and instrument parameter settings were optimized to obtain sensitive and accurate determination of most intensively ionizing toxins (deoxynivalenol, nivalenol, zearalenon, actyldeoxynivalenol, deepoxy-deoxynivalenol, fusarenon-X, altenuene, alternariol, alternariolmethylether, diacetoxyscirpenol, sterigmatocystin). The lowest calibration levels (LCLs) estimated for the respective analytes ranged from 50 to 150 μg kg−1. Quantitative analysis was performed either with the use of matrix-matched standards or by employing commercially available 13C-labeled internal standards (available for deoxynivalenol, nivalenol and zearalenon). Good recoveries (100-108%) and repeatabilities (RSD 5.4-6.9%) were obtained at spiking level 500 μg kg−1 with isotope dilution technique. Based on matrix-matched calibration, recoveries and repeatabilities were in the range 84-118% and 7.9-12.0% (RSD), respectively. The trueness of data obtained for deoxynivalenol and zearalenon in wheat/maize by DART-orbitrapMS was demonstrated by analysis of certified reference materials (CRMs). Good agreement of these results with data generated by validated ultra-high pressure liquid chromatography-time-of-flight mass spectrometry method was documented. 相似文献
982.
针对微波散射计资料的海面风场反演,本文首先利用QuikSCAT卫星散射计的近实时资料,借助荷兰皇家气象学会的SeaWinds散射计数据处理模式,在不同风速和海域的情况下,采用多解方案结合二维变分同化方法进行风向的模糊去除,达到消除解的不唯一性的目的,且对4种反演结果(低速风、中速风、高速风和近海岸风)与美国国家海洋和大气管理局卫星资料中心的近实时风场数据的对比分析,说明了该技术的有效性.在此基础上,对反演得到的中速风场利用广义变分最佳分析方法进行了调整,调整后的风场结构有了进一步的改善.此方法可为我国散射计资料反演海面风场的研究提供新的思路和方法.
关键词:
多解方案
二维变分同化
广义变分最佳分析
正则化方法 相似文献
983.
984.
985.
范德瓦尔斯方程的分子平均场理论推导 总被引:1,自引:0,他引:1
利用气体分子动理论和分子平均场理论,导出了真实气体物态方程--范德瓦尔斯方程,并与统计力学严格的理论推导结果作比较,得到了反映真实气体分子作用域大小的一个较为具体的参考值. 相似文献
986.
The article presents a proposal for a new method of automatic quality control of microlenses arrays, which is based on a semiderivative
real filter. The use of the semiderivative filter for examining pure-phase objects involves modifying the spatial frequency.
The basis of the proposed setup is a 4f correlator setup with coherent light. The phase object examined is placed in the input
plane of the correlator. Next, the light passes through a filter located in the frequency plane, which gives an intensity
signal. In the output plane a charge-coupled device (CCD) camera registers the light intensity, the range of which informs
the shape of the phase object. The proposed method is shift invariant, so it allows for examination of single elements or
a set of micro-optical elements simultaneously. Additionally, the same setup allows for measuring the phase of objects whose
thickness is either considerably smaller or much bigger than 2π. 相似文献
987.
Christopher D. Sinclair 《Journal of statistical physics》2009,136(1):17-33
Using the method of Tracy and Widom we rederive the correlation functions for β=1 Hermitian and real asymmetric ensembles of N×N matrices with N odd.
This research was supported in part by the National Science Foundation (DMS-0801243). 相似文献
988.
S. Hu and Y. Sun[1] defined the fixed point index for weakly inward mappings, investigated its properties and studied fixed points for such mappings. In this paper, following S. Hu and Y. Sun, we further investigate boundary conditions, under which the fixed point index for i(A,Ω, p) is equal to nonzero, where i(A,Ω, p) is the completely continuous and weakly inward mapping. Correspondingly, we can obtain many new fixed point the-orems of the completely continuous and weakly inward mapping, which generalize... 相似文献
989.
A nonassociative algebra is defined to be zeropotent if the square of any element is zero. In this paper, we give a complete classification of three-dimensional zeropotent algebras over the real number field up to isomorphism. By restricting the result to the subclass of Lie algebras, we can obtain a classification of three-dimensional real Lie algebras, which is in accordance with the Bianchi classification. Moreover, three-dimensional zeropotent algebras over a real closed field are classified in the same manner as those over the real number field. 相似文献
990.
Let T be a consistent o-minimal theory extending the theory of densely ordered groups and let be a consistent theory. Then there is a complete theory extending T such that T is an open core of , but every model of interprets a model of . If is NIP, can be chosen to be NIP as well. From this we deduce the existence of an NIP expansion of the real field that has no distal expansion. 相似文献