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81.
申明金 《广东微量元素科学》2011,18(6):33-36
采用数量化理论的方法.以金银花中微量元素含量作为变量,进行了产地分类,分析结果表明,金银花按产地可分3类:新密、封丘和平邑为一类;南京为一类;昆明和桂林为一类.结果与生产实际一致. 相似文献
82.
A method for determining the orbit types of the action of the group of gauge transformations on the space of connections for gauge theories with gauge group SU(n) in spacetime dimension d4 is presented. The method is based on the one-to-one correspondence between orbit types and holonomy-induced reductions of the underlying principal SU(n)-bundle. It is shown that the orbit types are labelled by certain cohomology elements of spacetime satisfying two relations. Thus, for every principal SU(n)-bundle the corresponding stratification of the gauge orbit space can be explicitly determined. As an application, a criterion characterizing kinematical nodes for physical states in Yang–Mills theory with the Chern–Simons term proposed by Asorey et al. is discussed. 相似文献
83.
H. W. Schffer P. H. Mokler R. W. Dunford C. Kozhuharov A. Krmer A. E. Livingston T. Ludziejewski H. -T. Prinz P. Rymuza L. Sarkadi Z. Stachura Th. Sthlker P. Swiat A. Warczak 《Physics letters. A》1999,260(6):331-494
The photon energy differential shape of the second order matrix element for the two-photon (2E1) decay of the 1s2s1S0 level in He-like gold has been measured. The results are in agreement with a recent fully relativistic calculation. The corresponding 2E1 matrix element deviates from those in lighter He-like systems due to the strong central field in a heavy two-electron ion. 相似文献
84.
Recently, linear programming problems with special structures have assumed growing importance in mathematical programming.
It is well known that exploiting network structures within linear programs can lead to considerable improvement of the computational
solution of large-scale linear programming problems. A linear program is said to contain an embedded network structure provided
that some subset of its constraints can be interpreted as specifying conservation of flow. If a column of the constraint matrix
has at most two non-zeros, then it leads to embedded generalized network structure and if these non-zeros are unit elements
and of opposite signs, then it leads to embedded pure network structure.
In this paper, we are concerned with algorithms for detecting embedded pure network structures within linear programs. The
network extraction methods are presented in two groups. The first group covers deletion and addition based algorithms and
the second group covers GUB based algorithms. We have extended the GUB based algorithm appearing in the second group by introducing
Markowitz merit count approach for exploiting matrix non zeros. A set of well known test problems has been used to carry out
computational experiments which show that our extensions to the GUB based algorithms give better results than the algorithms
reported earlier. 相似文献
85.
Christopher?J.?FewsterEmail author Izumi?ojima Martin?Porrmann 《Letters in Mathematical Physics》2005,73(1):1-15
In this Letter we try to settle some confused points concerning the use of the notion of p-nuclearity in the mathematical and physical literature, pointing out that the nuclearity index in the physicists’ sense vanishes for any p> 1. Our discussion of these issues suggests a new perspective, in terms of ε-entropy and operator spaces, which might permit connections to be drawn between phase space criteria and quantum energy inequalities.Mathematics Subject Classification (2000): 81T05, 47B10, 47L25. 相似文献
86.
Loc Teyssier 《Journal of Differential Equations》2004,205(2):390-407
We consider germs of holomorphic vector fields near the origin of with a saddle-node singularity, and the induced singular foliations. In a previous article we described the invariants addressing the analytical classification of these vector fields. They split into three parts: a formal, an orbital and a tangential component. For a fixed formal class, the orbital invariant (associated to the foliation) was obtained by Martinet and Ramis; we give it an integral representation. We then derive examples of non-orbitally conjugated foliations by the use of a “first-step” normal form, whose first-significative jet is an invariant. The tangential invariant also admits an integral representation, hence we derive explicit examples of vector fields, inducing the same foliation, that are not mutually conjugated. In addition, we provide a family of normal forms for vector fields orbitally equivalent to the model of Poincaré-Dulac. 相似文献
87.
G-protein coupled receptors (GPCRs) play a key role in different biological processes, such as regulation of growth, death and metabolism of cells. They are major therapeutic targets of numerous prescribed drugs. However, the ligand specificity of many receptors is unknown and there is little structural information available. Bioinformatics may offer one approach to bridge the gap between sequence data and functional knowledge of a receptor. In this paper, we use a bagging classification tree algorithm to predict the type of the receptor based on its amino acid composition. The prediction is performed for GPCR at the sub-family and sub-sub-family level. In a cross-validation test, we achieved an overall predictive accuracy of 91.1% for GPCR sub-family classification, and 82.4% for sub-sub-family classification. These results demonstrate the applicability of this relative simple method and its potential for improving prediction accuracy. 相似文献
88.
In this paper, we prove that the linearized elasticity system has
no eigenvalues in two geometric situations: the whole space
and a local perturbation of the half-space. We consider the Lamé coefficients and the
density varying in an unbounded part of the domain. For the whole space,
we use the operations curl and div
to reduce our system to a scalar problem
and use a limiting absorption principle for the reduced scalar equation
given by the partial Fourier transform. For the perturbed half-space, this
decompositions being no longer valid, we give an other method based on a
pseudo-decomposition using the operations div
and curl in the horizontal
direction. In contrast to the whole space case, the reduced problems depend
strongly on the dual Fourier variable which do not enable us to use same
techniques. To study these reduced problems, we use the analytic theory of
linear operators. 相似文献
89.
We establish a discrepancy theorem for signed measures, with a given positive part, which are supported on an arbitrary convex
curve. As a main application, we obtain a result concerning the distribution of zeros of polynomials orthogonal on a convex
domain. 相似文献
90.
M. I. Ganzburg 《Constructive Approximation》2001,17(2):275-306
We study Pólya-and Remez-type inequalities for univariate and multivariate polynomials and discuss their applications to Nikolskii-type
inequalities and upper estimates of trigonometric integrals. 相似文献