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31.
We construct cellular homotopy theories for categories of simplicial presheaves on small Grothendieck sites and discuss applications to the motivic homotopy category of Morel and Voevodsky. 相似文献
32.
In this paper, we present a numerical scheme for solving the coupled system of compressible miscible displacement problem in porous media. The flow equation is solved by the mixed finite element method, and the transport equation is approximated by a discontinuous Galerkin method. The scheme is continuous in time and a priori hp error estimates is presented. 相似文献
33.
M. Frigon 《Journal of Fixed Point Theory and Applications》2007,1(2):189-194
We present results on the global existence of analytic solutions to the Cauchy problem in starshaped or convex complex domains.
No growth conditions are imposed. Our results rely on a notion of solution-tube that we introduce.
à la mémoire de Jean Leray 相似文献
34.
Catherine Cordier-Robert Thierry Grosdidier Gang Ji Jacques Foct 《Hyperfine Interactions》2006,168(1-3):951-957
Microstructured (atomized) and nanostructured (milled) Fe60Al40 powders together with their corresponding coatings synthesized by High Velocity Oxy-fuel (HVOF) or Atmospheric Plasma Spray (APS) thermal spraying techniques have been characterized by Mössbauer Spectroscopy (MS) and X-ray Diffraction (XRD). The evolution of the microstructure and the atomic ordering degree in the powders and coatings are discussed at the light of the various processing conditions. The operational correlation between the parameters of the duplex morphology of coatings and the processing parameters is discussed. 相似文献
35.
S.A. Grigorian 《Topology and its Applications》2006,153(18):3598-3614
Finite-sheeted covering mappings onto compact connected groups are studied. We show that for a covering mapping from a connected Hausdorff topological space onto a compact (in general, non-abelian) group there exists a topological group structure on the covering space such that the mapping becomes a homomorphism of groups. To prove this fact we construct an inverse system of covering mappings onto Lie groups which approximates the given covering mapping. As an application, it is shown that a covering mapping onto a compact connected abelian group G must be a homeomorphism provided that the character group of G admits division by degree of the mapping. We also get a criterion for triviality of coverings in terms of means and prove that each finite covering of G is equivalent to a polynomial covering. 相似文献
36.
3d-metal antimonides: Fe1+x Sb, N+x Sb, Co+x Sb and the (Ni1?y Fe y )Sb solid solution have been studied by the Mössbauer effect method at 57Fe and 119Sn. It was found that the quadrupole interactions at the Fe and Sn nucleus in 3d-metal antimonides are very sensitive to the filling of different crystallographic sites with metal atoms. The metal atoms in trigonal-bipyramidal sites have a strong effect on the quadrupole splitting of 119Sn. They are nearest to anions (Sb or Sn) with the typical axial ratio of c/a = 1.25. The QS(x) dependence of 119 Sn in 3d-metal antimonides in the 0 ≤ x ≤ 0.1 concentration range can be used to determine x – the concentration of transition metal excess relative to the stoichiometric composition. 相似文献
37.
Yu. D. Perfiliev V. S. Rusakov L. A. Kulikov A. A. Kamnev K. Alkhatib 《Hyperfine Interactions》2006,167(1-3):881-885
To explain line broadening in emission Mössbauer spectra as compared to the corresponding absorber measurements, the model of trapped electrons has been proposed. Auger electrons (emitted, e.g. after electron capture by 57Co or after the converted isomeric transition of 119mSn), as well as secondary electrons, may be trapped in the proximity to the nucleogenic ion. Electrons captured by lattice traps at different distances from the daughter ion induce an asymmetric distribution of quadrupole splitting in the resulting emission spectra, as shown in a few examples. This model is supported by estimates of quadrupole splitting values which may be caused by such trapped electrons located at specified distances from the nucleogenic atom. 相似文献
38.
Eliza P. de Jager 《Topology and its Applications》2007,154(10):2117-2126
We show that the infimum of any family of proximally symmetric quasi-uniformities is proximally symmetric, while the supremum of two proximally symmetric quasi-uniformities need not be proximally symmetric. On the other hand, the supremum of any family of transitive quasi-uniformities is transitive, while there are transitive quasi-uniformities whose infimum with their conjugate quasi-uniformity is not transitive. Moreover we present two examples that show that neither the supremum topology nor the infimum topology of two transitive topologies need be transitive. Finally, we prove that several operations one can perform on and between quasi-uniformities preserve the property of having a complement. 相似文献
39.
We prove a conjecture by F. Ferrari. Let X be the total space of a nonlinear deformation of a rank two holomorphic vector bundle on a smooth rational curve, such that X has trivial canonical bundle and has sections. Then the normal bundle to such sections is computed in terms of the rank of the Hessian of a suitably defined superpotential at its critical points. 相似文献
40.
We investigate separability questions for the mapping class group of a surface. While this group is not subgroup separable in general, we prove a large family of interesting subgroups are separable. This includes many classically studied subgroups such as solvable subgroups, Heegaard and Handlebody groups, geometric subgroups, and all the terms in the Johnson filtration. 相似文献