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991.
Damien Vergnaud 《Journal of Number Theory》2009,129(6):1212-1233
A linear independence measure over Q is obtained for values of some generalized hypergeometric functions at rational points and for the squares of real periods and quasi-periods of elliptic curves in Legendre form y2=x(x−1)(x−1/q) for almost every q∈Z. 相似文献
992.
M. A. Navascués 《Acta Appl Math》2009,106(1):93-104
A very general method of fractal interpolation on T
1 is proposed in the first place. The approach includes the classical cases using trigonometric functions, periodic splines,
etc. but, at the same time, adds a diversity of fractal elements which may be more appropriate to model the complexity of
some variables. Upper bounds of the committed error are provided. The arguments avoid the use of derivatives in order to handle
a wider framework. The Lebesgue constant of the associated partition plays a key role. The procedure is proved convergent
for the interpolation of specific functions with respect to some nodal bases. In a second part, the approximation is then
extended to bidimensional tori via tensor product of interpolation spaces. Some sufficient conditions for the convergence
of the process in the Fourier case are deduced.
相似文献
993.
Franki Dillen Johan Fastenakels Joeri Van der Veken 《Annals of Global Analysis and Geometry》2009,35(4):381-396
We show a way to choose nice coordinates on a surface in and use this to study minimal surfaces. We show that only open parts of cylinders over a geodesic in are both minimal and flat. We also show that the condition that the projection of the direction tangent to onto the tangent space of the surface is a principal direction, is equivalent to the condition that the surface is normally
flat in . We present classification theorems under the extra assumption of minimality or flatness.
J. Fastenakels is a research assistant of the Research Foundation—Flanders (FWO).
J. Van der Veken is a postdoctoral researcher supported by the Research Foundation—Flanders (FWO).
This work was partially supported by project G.0432.07 of the Research Foundation—Flanders (FWO). 相似文献
994.
From J-action point of views, slant surfaces are the simplest and the most natural surfaces of a (Lorentzian) Kähler surface (\(\tilde M,\tilde g\), J). Slant surfaces arise naturally and play some important roles in the studies of surfaces of Kähler surfaces (see, for instance, [13]). In this article, we classify quasi-minimal slant surfaces in the Lorentzian complex plane C 1 2 . More precisely, we prove that there exist five large families of quasi-minimal proper slant surfaces in C 1 2 . Conversely, quasi-minimal slant surfaces in C 1 2 are either Lagrangian or locally obtained from one of the five families. Moreover, we prove that quasi-minimal slant surfaces in a non-flat Lorentzian complex space form are Lagrangian. 相似文献
995.
996.
We derive interior L
p
-estimates for solutions of linear elliptic systems with oscillatory coefficients. The estimates are independent of ε, the small length scale of the rapid oscillations. So far, such results are based on potential theory and restricted to periodic
coefficients. Our approach relies on BMO-estimates and an interpolation argument, gradients are treated with the help of finite
differences. This allows to treat coefficients that depend on a fast and a slow variable. The estimates imply an L
p
-corrector result for approximate solutions.
相似文献
997.
The structures, energetics, spectroscopies, and stabilities of the doublet [Si, C, N, O] radical are explored at the density functional theory and ab initio levels. Sixteen isomers are located, connected by 29 interconversion transition states. At the CCSD(T)/6-311+G(2df)//QCISD/6-311G(d)+ZPVE level, the lowest lying isomer is a linear SiNCO 1 (0.0 kcal/mol) mainly featuring a cumulene | . Si = N = C = O. The second and third low-lying isomers are bent OSiCN 2 (8.8) and bent OSiNC 3 (11.1), respectively. All the three low-lying isomers 1, 2, 3, and another high-lying species 5 (75.4) with a linear SiCNO structure are shown to have considerable kinetic stability and may be experimentally observable. The predicted results of isomers 1 and 2 are consistent with the previous mass spectrometry experiments. Moreover, the fourth low-lying species SiOCN 4 (23.9) with bent structure is expected to be observable in low-temperature environments. The bonding nature of the five isomers 1, 2, 3, 4, and 5 is analyzed. The calculated results are compared with those of the analogous molecules C(2)NO and Si(2)NO. Implications in interstellar space and N,O-doped SiC vaporization processes are also discussed. 相似文献
998.
F. J. Ló pez Francisco Martin Santiago Morales 《Transactions of the American Mathematical Society》2006,358(9):3807-3820
The existence of complete minimal surfaces in a ball was proved by N. Nadirashvili in 1996. However, the construction of such surfaces with nontrivial topology remained open. In 2002, the authors showed examples of complete orientable minimal surfaces with arbitrary genus and one end. In this paper we construct complete bounded nonorientable minimal surfaces in with arbitrary finite topology. The method we present here can also be used to construct orientable complete minimal surfaces with arbitrary genus and number of ends.
999.
We prove that many complete, noncompact, constant mean curvature (CMC) surfaces
are nondegenerate; that is, the Jacobi operator Δf + | Af |2 has no L2 kernel. In fact, if ∑ has genus zero with k ends, and if f (∑) is embedded (or Alexandrov immersed) in a half-space, then we find an explicit upper bound for the dimension of the L2 kernel in terms of the number of non-cylindrical ends. Our main tool is a conjugation operation on Jacobi fields which linearizes
the conjugate cousin construction. Consequences include partial regularity for CMC moduli space, a larger class of CMC surfaces
to use in gluing constructions, and a surprising characterization of CMC surfaces via spinning spheres.
R.K. partially supported by NSF grants DMS-0076085 at GANG/UMass and DMS-9810361 at MSRI, and by a FUNCAP grant in Fortaleza,
Brazil. J.R. partially supported by an NSF VIGRE grant at Utah.
Received: January 2005; Accepted: June 2005 相似文献
1000.
On the chemical structure of phosphorus compounds in phosphoric acid-activated carbon 总被引:1,自引:0,他引:1
Chemical structure of phosphorus species in polymer-based phosphoric acid-activated carbon SP800 was investigated by X-ray photoelectron spectroscopy. It has been shown that most probable structure for phosphorus species is condensed phosphates bound to carbon lattice via COP bonding. 相似文献