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171.
Analytical methods applied to the determination of pesticide residues in foods of animal origin. A review of the past two decades 总被引:5,自引:0,他引:5
LeDoux M 《Journal of chromatography. A》2011,1218(8):1021-1036
Pesticides are widely used in agriculture and can be transferred to animals in a number of ways. Consequently, reliable analytical methods are required to determine pesticide residues in foods of animal origin. The present review covers published methods and research articles (1990-2010) in which pesticide residues have been extracted from meat and meat products, milk and dairy products, fish and seafood, and eggs, then cleaned up, and isolated by chromatographic techniques to be identified and quantified by various detection methods. Recovery rates, quantification limits, the matrix effect and related parameters have all been considered. Lastly, future developments in this field are outlined. 相似文献
172.
In Peller (1980) [27], Peller (1985) [28], Aleksandrov and Peller (2009) [2], Aleksandrov and Peller (2010) [3], and Aleksandrov and Peller (2010) [4] sharp estimates for f(A)−f(B) were obtained for self-adjoint operators A and B and for various classes of functions f on the real line R. In this paper we extend those results to the case of functions of normal operators. We show that if a function f belongs to the Hölder class Λα(R2), 0<α<1, of functions of two variables, and N1 and N2 are normal operators, then ‖f(N1)−f(N2)‖?const‖fΛα‖‖N1−N2α‖. We obtain a more general result for functions in the space for an arbitrary modulus of continuity ω. We prove that if f belongs to the Besov class , then it is operator Lipschitz, i.e., . We also study properties of f(N1)−f(N2) in the case when f∈Λα(R2) and N1−N2 belongs to the Schatten–von Neumann class Sp. 相似文献
173.
We refine the cyclic cohomological apparatus for computing the Hopf cyclic cohomology of the Hopf algebras associated to infinite primitive Cartan–Lie pseudogroups, and for the transfer of their characteristic classes to foliations. The main novel feature is the precise identification as a Hopf cyclic complex of the image of the canonical homomorphism from the Gelfand–Fuks complex to the Bott complex for equivariant cohomology. This provides a convenient new model for the Hopf cyclic cohomology of the geometric Hopf algebras, which allows for an efficient transport of the Hopf cyclic classes via characteristic homomorphisms. We illustrate the latter aspect by indicating how to realize the universal Hopf cyclic Chern classes in terms of explicit cocycles in the cyclic cohomology of étale foliation groupoids. 相似文献
174.
175.
We give new bounds and asymptotic estimates on the largest Kronecker and induced multiplicities of finite groups. The results apply to large simple groups of Lie type and other groups with few conjugacy classes. 相似文献
176.
The present article is focused on the study of a special class of systems of non-linear transcendental equations for which classical algebraic and symbolic methods are inapplicable. For the purpose of study of such systems we develop a method for computing residue integrals with integration over certain cycles. We describe conditions under which the mentioned residue integrals coincide with power sums of the inverses to the roots of a system of equations (i.e. multidimensional Waring’s formulas). Based on this, we develop an algorithm that computes such power sums without computing the roots. As an application of the suggested method, we consider a problem of finding sums of multi-variable number series. 相似文献
177.
On a Comparative Study on Some Trigonometric Classes of Distributions by the Analysis of Practical Data Sets 下载免费PDF全文
The aim of this paper is twofold. Firstly, we elaborate and investigate a new trigonometric class of distribution, called the type II Tan-G class. Secondly, we perform a practical comparative evaluation of certain trigonometric classes; the Sin-G, Cos-G, Tan-G classes and the new one, with each other and with their common baseline distribution. More specifically, the usefulness and flexibility of these trigonometric classes are demonstrated through twelve practical data sets, by using the Weibull distribution as baseline. Among the data sets, two of them concern the Covid-19 pandemic in France from March to June 2020. As main results, it is shown that the related trigonometric models can outperform the former Weibull model in various cases and that the proposed type II Tan Weibull model can be, in certain situations, the best of them. The main lines of the code written in the \textsf{R} software language are provided. 相似文献
178.
H. France-Jackson 《Acta Mathematica Hungarica》2002,93(3):249-251
Two special classes are said to be similar if they determine the same upper radical. A necessary and sufficient condition for a special radical to be generated by distinct similar special classes is given and all similar special classes generating a given special radical are described. 相似文献
179.
M. -B. A. Babaev 《Mathematical Notes》1997,62(1):15-29
We study the approximation of functions of several variables by bilinear forms that are the pairwise products of functions
of fewer variables. The order of approximation of Sobolev classesW
q
r
by bilinear forms inL
p
for 2≤q≤p≤∞ is found.
Translated by N. K. Kulman
Translated fromMatematicheskie Zametki, Vol. 62, No. 1, pp. 18–34, July, 1997. 相似文献
180.
合成乳酸乙酯精馏残液的分析张青枝,华国雄,鲁富贵,张深松,赵根锁(河南师范大学化学系新乡453002)(河南省化学研究所郑州)关键词乳酸乙酯,精馏残液,红外光谱,电子轰击质谱采用乳酸、乙醇直接酯化法[1],有机溶剂共沸法[2],合成乳酸乙酯收率较低。... 相似文献