Reconstruction of closely spaced small inhomogeneities via boundary measurements for the full time-dependent Maxwell’s equations

We consider for the full time-dependent Maxwell’s equations the inverse problem of identifying locations and certain properties of small electromagnetic inhomogeneities in a homogeneous background medium from dynamic boundary measurements on the boundary for a finite time interval.     

Nonlinear Degenerate Anisotropic Elliptic Equations with Variable Exponents and L1 Data

This paper is devoted to the study of a nonlinear anisotropic elliptic equation with degenerate coercivity, lower order term and L¹ datum in appropriate anisotropic variable exponents Sobolev spaces. We obtain the existence of distributional solutions.     

Effect of Preparation Conditions on the Stability of Pt/Al2O3 Catalysts in Methane Combustion

Alumina supported platinum catalysts were prepared by sol-gel method using aluminum-sec-butoxide, platinum acetylacetonate and sec-butanol. Various gelation process were performed either by the help of a gelation agent (water or acetic acid) or by a slow condensation without hydrolysis source. The textural and the structural study of the catalysts using the nitrogen physical adsorption and the hydrogen chemisorption showed that the BET surface area and the metal dispersion varied when the hydrolysis and the gelation processes were modified. The catalytic activities for methane combustion performed on the fresh and aged catalysts were correlated to the metal dispersion values. In addition the catalytic activity loss under reaction mixture seemed to be caused by the metal dispersion decrease. When the catalysts were aged under the reaction mixture at 600°C for 72 h, a BET surface area decrease and a metallic surface area loss were observed. The resistance to sintering observed to be dependant on the hydrolysis and the gelation processes was in favor of the catalyst prepared by acetic acid.     

Asymptotic behaviour of the energy for electromagnetic systems in the presence of small inhomogeneities

In this article we consider solutions to the time-harmonic and time-dependent Maxwell's systems with piecewise constant coefficients with a finite number of small inhomogeneities in ?³. In time-harmonic case and for such solutions, we derive the asymptotic expansions due to the presence of small inhomogeneities embedded in the entire space. Further, we analyse the behaviour of the electromagnetic energy caused by the presence of these inhomogeneities. For a general time-dependent case, we show that the local electromagnetic energy, trapped in the total collection of these well-separated inhomogeneities, decays towards zero as the shape parameter decreases to zero or as time increases.     

Asymptotic property and convergence estimation for the eigenelements of the Laplace operator

In this article, we provide a rigorous derivation of asymptotic expansions for eigenfunctions and we establish convergence estimation for both eigenvalues and eigenfunctions of the Laplacian. We address the integral equation method to investigate the interplay between the geometry, boundary conditions and spectral properties of the eigenelements of the Laplace operator under deformation of the domain. The asymptotic formula and convergence estimation are tested by numerical examples.     

New Gelation Process for Pt/Al2O3 Catalysts Preparation

Gel of platinum and aluminum was prepared by an anhydrous gelation process using a mixture of aluminum sec butoxid, platinum acetylacetonate and Butanol-2. The investigation of this gelation by FTIR, UV-vis and ²⁷Al NMR spectroscopies suggest that a slow polymerization of aluminum precursors occurs according to an etheration mecanism likely catalysed by metallic platinum which could be formed by the reduction of platinum in Pt(acac)₂ by sBuOH in the mixture during aging.     

Characterization and comparison between Ig(Vgs) structures HEMT AlInN/GaN and AlGaN/GaN

In this paper, we have studied the Schottky contact of two structures AlInN/GaN and AlGaN/GaN in transistors HEMTs. The current–voltage Igs(Vgs) of AlInN/GaN and AlGaN/GaN structures were investigated at room temperature. The electrical parameters such as ideality factor (2.3 and 1.96), barrier height (0.72 and 0.71 eV) and series resistance (33 and 153 $\Omega $ ) were evaluated from I–V data. The comparison of the performance of the two structures AlInN/GaN and AlGaN/GaN in transistors HEMTs have been analyzed and discussed.     

Electronic states of CsLi and CsLi<Superscript>+</Superscript> molecules

Configuration interaction calculations have been carried out on electronic states of the CsLi molecule and the CsLi⁺ cation. Adiabatic potential energy, spectroscopic constants, dipole moments, and vibrational levels are presented for the lowest states of ^1,3Σ⁺, ^1,3Π, and ^1,3Δ symmetries of the alkali dimer CsLi molecule dissociating into Cs (6s, 6p, 5d, 7s, and 7p) + Li (2s, 2p, 3s, 3p, and 3d) as well as for the lowest ²Σ⁺, ²Π, and ²Δ electronic states of the CsLi⁺ cation dissociating into Li (2s, 2p, 3s, 3p, and 3d) + Cs⁺ and Li⁺ + Cs (6s, 6p, 5d, 7s, and 7p). The results of the present many-electron configuration interaction calculations on the cation support the previous core-polarization effective potential calculations. The present calculations on the CsLi molecule are complementary to previous theoretical work on this system, including recently observed electronic states that had not been calculated previously. We have used an ab initio approach involving a nonempirical pseudopotential for the Li (1s²) and Cs cores and a core-valence correlation correction. A very good agreement of data from spectroscopic constants for some of the lowest states of the CsLi and CsLi⁺ molecules with those available in recent theoretical works has been obtained. The existence of numerous avoided crossings between electronic states of ²Σ⁺ and ²Π symmetries is related to a charge transfer process between the two ionic CsLi⁺ and LiCs⁺ systems.