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61.
J. M. Garcia O. Sanchez P. Segovia J. E. Ortega J. Alvarez A. L. Vazquez de Parga R. Miranda 《Applied Physics A: Materials Science & Processing》1995,61(6):609-613
We observe the partial confinement of the twodimensional electron gas of ans-p-like surface state by the regular step distribution of several vicinal Cu(111) surfaces. The spatial distribution of the surface state is visualized by scanning tunneling microscopy. Local tunneling spectroscopy reveals a shift of the maximum of the density of states of the surface state towards the Fermi level, which correlates with the size of the terraces. The average shift is also measured by angle-resolved photoemission and found to be consistent with a one-dimensional Kronig-Penney model. 相似文献
62.
In this paper we study the bilinear problem of characterizing the positive Borel measures μ on S n, satisfying where $H_s^2(w)$ and $H_t^2(w)$ are weighted Hardy‐Sobolev spaces, under adequate conditions on the weight w. 相似文献
63.
N. Jaouen J.M. Tonnerre D. Raoux L. Ortega E. Bontempi M. Münzenberg W. Felsch M. Suzuki H. Maruyama H.A. Dürr E. Dudzik G. van der Laan 《Applied Physics A: Materials Science & Processing》2001,72(6):711-715
The element and electronic shell specificities of X-ray resonant magnetic scattering have been used to investigate the magnetization
of Ce 5d and Fe 3d states in [CeH2(19.6 ?)/Fe(25.4 ?)]*38 a multilayer. We show that the measurement of the magnetic contribution to the intensities reflected
at low angles at the Ce L2 and Fe L2,3 edges allows us to investigate the profile of the Ce 5d and Fe 3d magnetic polarization. The Fe 3d polarization is found
to be uniform across the Fe layer and the Ce 5d polarization appears to be restricted close to the interface with Fe.
Received: 22 May 2001 / Accepted: 4 July 2001 / Published online: 5 October 2001 相似文献
64.
65.
A. Ortega 《国际化学动力学杂志》2001,33(6):343-353
An account of conventional dynamic thermal analysis (TA) with respect to uncertainties, failures, successes, and limitations as applied to solid‐state (s‐s) processes is discussed. A review of some controversial aspects of TA is presented. The scope is to discuss in three parts the adequate understanding of TA and to open a controversy about the dynamic methods and about the necessity of stimulating a consensus between scientists for a better TA. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 343–353, 2001 相似文献
66.
Manuel J. Castro Sergio Ortega Marc de la Asunción José M. Mantas José M. Gallardo 《Comptes Rendus Mecanique》2011,339(2-3):165-184
This article is a review of the work that we are carrying out to efficiently simulate shallow water flows. In this paper, we focus on the efficient implementation of path-conservative Roe type high-order finite volume schemes to simulate shallow flows that are supposed to be governed by the one-layer or two-layer shallow water systems, formulated under the form of a conservation law with source terms. The implementation of the scheme is carried out on Graphics Processing Units (GPUs), thus achieving a substantial improvement of the speedup with respect to normal CPUs. Finally, some numerical experiments are presented. 相似文献
67.
68.
We present a quick review of several reduction techniques for symplectic and Poisson manifolds using local and global symmetries compatible with these structures. Reduction based on the standard momentum map (symplectic or Marsden–Weinstein reduction) and on generalized distributions (the optimal momentum map and optimal reduction) is emphasized. Reduction of Poisson brackets is also discussed and it is shown how it defines induced Poisson structures on cosymplectic and coisotropic submanifolds. 相似文献
69.
Jaime Ortega Jorge San Martín Loredana Smaranda 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2007,58(6):969-993
In this paper, we use the Bloch wave method to study the asymptotic behavior of the solution of the Laplace equation in a
periodically perforated domain, under a non-homogeneous Neumann condition on the boundary of the holes, as the size of the
holes goes to zero more rapidly than the domain period. This method allows to prove that, when the hole size exceeds a given
threshold, the non-homogeneous boundary condition generates an additional term in the homogenized problem, commonly referred
to as “the strange term” in the literature. 相似文献
70.
Evolutionary multi-objective optimization algorithms aim at finding an approximation of the Pareto set. For hard to solve problems with many conflicting objectives, the number of functions evaluations to represent the Pareto front can be large and time consuming. Parallel computing can reduce the wall-clock time of such algorithms. Previous studies tackled the parallelization of a particular evolutionary algorithm. In this research, we focus on improving one of the most time consuming procedures—the non-dominated sorting—, which is used in the state-of-the-art multi-objective genetic algorithms. Here, three parallel versions of the non-dominated sorting procedure are developed: (1) a multicore (based on Pthreads); (2) a Graphic Processing Unit (GPU) (based on CUDA interface); and (3) a hybrid (based on Pthreads and CUDA). The user can select the most suitable option to efficiently compute the non-dominated sorting procedure depending on the available hardware. Results show that the use of GPU computing provides a substantial improvement in terms of performance. The hybrid approach has the best performance when a good load balance is established among cores and GPU. 相似文献