Global Existence and Regularity for the 3D Stochastic Primitive Equations of the Ocean and Atmosphere with Multiplicative White Noise

The Primitive Equations are a basic model in the study of large scale Oceanic and Atmospheric dynamics. These systems form the analytical core of the most advanced General Circulation Models. For this reason and due to their challenging nonlinear and anisotropic structure the Primitive Equations have recently received considerable attention from the mathematical community. In view of the complex multi-scale nature of the earth's climate system, many uncertainties appear that should be accounted for in the basic dynamical models of atmospheric and oceanic processes. In the climate community stochastic methods have come into extensive use in this connection. For this reason there has appeared a need to further develop the foundations of nonlinear stochastic partial differential equations in connection with the Primitive Equations and more generally. In this work we study a stochastic version of the Primitive Equations. We establish the global existence of strong, pathwise solutions for these equations in dimension 3 for the case of a nonlinear multiplicative noise. The proof makes use of anisotropic estimates, $L^{p}_{t}L^{q}_{x}$ estimates on the pressure and stopping time arguments.Comment: To appear in Nonlinearit

Microscopic defects and homogeneity investigations in 4H-SiC epitaxial wafers by UV scanning photoluminescence spectroscopy

UV scanning photoluminescence spectroscopy is applied to 4H-SiC epitaxy characterization. In a first part, the technique is used for triangular defects characterization. The results show that two kinds of defects are present. Some defects are inclusion of cubic SiC which is confirmed by Raman spectroscopy. The other ones consist of staking faults of different thicknesses acting as quantum wells. In a second part, the effective lifetime profile is mapped for a whole 50 mm epitaxy using the variation of room temperature PL intensity versus excitation intensity

The impact of storms in the morphodynamic evolution of a human-impacted semi-sheltered beach (Agadir Bay, Morocco)

International audienceThis study discusses the morphological changes and evolution of Agadir Bay beach (Morocco) in response to eight storms between January 2014 and March 2014. A comparison is carried out of the evolution and variability of the beach in a sector of the bay protected by the commercial harbour of Agadir relative to a sector down drift of the harbour that is more exposed to waves, and changes affecting the beach following these storms are examined. Wave influence is evaluated using numerical simulations. The results show that despite being of relatively low intensity, the two first storm events, and especially storm 1, are responsible for major beach morphological changes. Three zones were identified as a function of the beach sediment dynamics: (i) a northern zone, representing the sector of the beach protected by Agadir harbour, with a net loss of about 21% of the total sediment, (ii) a southern zone, corresponding to the exposed sector with a net loss reaching74% of the total sediment, and (iii) a sector of residual dune that recorded no significant change during the storms. (C) 2015 Elsevier Ltd. All rights reserved

Multi-decadal shoreline and inner shoreface changes in response to development pressures, Agadir Bay, Morocco: a combined remote sensing, bathymetric-differencing, and wave-current modeling approach

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Optical Characterization of Full SiC Wafer

International audienceDifferent optical characterization tool for mapping of SiC electrical properties (mobility, free carrier concentration, doping, minority carrier effective lifetime) are reviewed. For each technique, advantages and drawbacks are discussed and the domain of use is presented. An original approach to determine the minority carrier lifetime from room temperature PL intensity is more particularly developed