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91.
In the context of non-abelian gerbes, we define a cubical version of categorical group 2-bundles with connection over a smooth manifold. We address their two-dimensional parallel transport, study its properties, and construct non-abelian Wilson surface functionals. 相似文献
92.
Starting with a non-abelian gerbe represented by a non-abelian differential cocycle, with values in a given crossed-module, this paper explicitly calculates a formula for the derivative of the associated surface holonomy of squares mapped into the base manifold; with spheres later considered as a special case. While the definitions in this paper used for gerbes, their connections, and the induced holonomy will initially be simplicial, translations into a cubical setting will be provided to aide in explicit coordinate-based calculations. While there are many previously published results on the properties of these non-abelian gerbes, including some calculations of the derivative over a single open set, this paper endeavors to take these local calculations and glue them together across multiple open sets in order to obtain a single expression for the change in surface holonomy with respect to a one-parameter family of squares. 相似文献
93.
V. A. Pestunovich S. N. Tandura M. G. Voronkov V. P. Baryshok G. I. Zelchan V. I. Glukhikh 《光谱学快报》2013,46(5):339-344
1H, 13C, 19F and 29Si NMR chemical shifts and coupling constants for Si-substituted silatranes, XSi(OCH2CH2)3N, and triethoxysilanes, XSi(OCH2CH3)3, where X = H, CH3, and F have been studied. Expansion of the coordination numbers of silicon and tin leads to similar changes in the NMR parameters. 相似文献
94.
Jeffrey D. Achter 《Journal of Pure and Applied Algebra》2006,204(2):316-333
For any sufficiently general family of curves over a finite field Fq and any elementary abelian ?-group H with ? relatively prime to q, we give an explicit formula for the proportion of curves C for which Jac(C)[?](Fq)≅H. In doing so, we prove a conjecture of Friedman and Washington. 相似文献
95.
J. M. Carnicer 《Advances in Computational Mathematics》1995,3(1):395-404
A set of multivariate data is called strictly convex if there exists a strictly convex interpolant to these data. In this
paper we characterize strict convexity of Lagrange and Hermite multivariate data by a simple property and show that for strict
convex data and given smoothness requirements there exists a smooth strictly convex interpolant. We also show how to construct
a multivariate convex smooth interpolant to scattered data.
Partially supported by DGICYT PS93-0310 and by the EC project CHRX-CT94-0522. 相似文献
96.
This paper considers monotonic (or causal) homotopy between trajectories of control systems. The main result is the construction of an analogue of the simply connected covering space. The constructed covering Γ(Σ,x) has the structure of a manifold and satisfies the property that two trajectories are monotonic homotopic if and only if the end points of their liftings coincide. 相似文献
97.
Nonexponential spin-lattice relaxation is often observed for rare spin nuclei in the solid state. Deviation from single-component decay may be amplified by the coupling of rare spin nuclei to paramagnetic centers. Nonexponential spin-lattice relaxation was observed in derivatized silica gels resins. This phenomenon was localized and enhanced when paramagnetic transition metal cations were bound to surface functional groups. A stretched exponential analysis method was determined to be robust in fitting nonexponential relaxation curves for silica gels both with and without bound paramagnetic ions. Spin-lattice relaxation rates (T1−1) for functional group nuclei increased as a function of percent surface coverage with metal ion. The magnitude of the relaxation rate increase was dependent upon internuclear distances from the paramagnetic center. At low surface coverages, a semi-random distribution of paramagnetic centers increased the degree of stretching of spin-lattice relaxation decays, as measured by decreases in the calculated stretching parameter β. At higher surface coverages, calculated β values reached a limiting value, indicating that while the spin-diffusion mechanism in metal-ex-changed silica gels is restricted, it is not completely diminished. 相似文献
98.
99.
Iwao Kimura 《manuscripta mathematica》1998,97(1):81-91
We consider class numbers of quadratic extensions over a fixed function field. We will show that there exist infinitely many
quadratic extensions which have class numbers not being divisible by 3 and satisfy prescribed ramification conditions.
Received: 24 October 1997 / Revised version: 26 February 1998 相似文献
100.
29Si MAS NMR spectra of natural melanophlogite as well as of synthetic melanophlogite indicate that the room temperature lattice structure has lower symmetry than expected from its proposed crystal structure. On heating the samples to temperatures above room temperature, the structure undergoes a reversible phase transition with a transition temperature characteristic of the locality. For the synthetic melanophlogite, the transition is over the range 298 K to 338 K. From low temperature NMR spectra it is concluded that the low temperature forms of synthetic melanophlogite and of melanophlogite from Sicily differ in their crystal lattice symmetries due to their characteristic guest species.Dedicated to Dr D. W. Davidson in honor of his great contributions to the sciences of inclusion phenomena.On leave Mineralogisches Institut, CAU KIEL, FRG 相似文献