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排序方式: 共有238条查询结果,搜索用时 11 毫秒
21.
Djamel Ait-Akli & Abdelkader Merakeb 《偏微分方程(英文版)》2020,33(1):64-92
In this paper we consider the Lamé system on a polygonal convex domain
with mixed boundary conditions of Dirichlet-Neumann type. An explicit L2 norm
estimate for the gradient of the solution of this problem is established. This leads to an
explicit bound of the H1 norm of this solution. Note that the obtained upper-bound is
not optimal. 相似文献
22.
Abdelkader Intissar 《Journal of Mathematical Analysis and Applications》2005,305(2):669-689
The Reggeon field theory is governed by a non-self adjoint operator constructed as a polynomial in A, A*, the standard Bose annihilation and creation operators. In zero transverse dimension, this Hamiltonian acting in Bargmann space is defined by
Hλ′,μ=λ′A*2A2+μA*A+iλA*(A*+A)A, 相似文献
23.
A direct computational approach for lifetime prediction of fibre-reinforced polymer (FRP) composites is presented. The approach is based on a direct method which allows predicting the fatigue life from the stabilised damage state. The classical direct method is generalised to the case of coupled plasticity with damage mechanics of the UD-FRP composite materials [1]. The constitutive model is based on a continuous damage meso-scale approach [2]. By analysing damage variables and thermodynamical forces associated with damage at the stabilised state, fatigue life prediction law is proposed as a power law function of stabilised thermodynamic forces. The obtained numerical results have been validated by experimental test results on standard glass-fibre/epoxy angle-ply and cross-ply laminate plates. The proposed approach could serve as a useful tool for the design of FRP composites. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
24.
The optimal control of water quality model is considered. We analyze a regularized version of the pointwise control. A numerical algorithm is presented. The solution approach is a combination of a TVD scheme for the shallow water equations and a purley deterministic particle method for the pollutant problem. We present some computational results. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
25.
We consider a simple but representative model incorporating the main behavior of the electromagnetic field near the edge of a patch antenna. Recall that this kind of antenna is obtained by a metal patch laying on a dielectric substrate covering a ground metallic plane. The functioning principle of such an electric device is based on the matching of an N-dimensional behavior of the field outside the antenna with an (N-1)-dimensional one inside the zone limited by the patch and the ground plane, N = 3 or 2 according to the considered model. In this study, we make use of the technique of matched asymptotic expansions and computation of singularities to describe this behavior for the two-dimensional case. Proved error estimates enable us to give a rigorous background to the underlying asymptotic analysis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
26.
Let A be a Banach algebra which does not contain any nonzero idempotent element, let γ > 0, and let
. We show that if
then
. We also show, assuming a suitable spectral condition on x, that if
, then
Received: 12 July 2006 Revised: 31 January 2007 相似文献
27.
In this paper, we calculate the band gap and the band discontinuities of a GaN
y
AsBi
x
structure lattice matched to GaAs substrate using the conduction and the valence band anticrossing models at the same time.
The results obtained show a good agreement with experiment. The nitrogen and the bismuth concentrations leading to a wavelength
emission of 1.55 μm have been determined (x = 3.5%, y = 2%). This structure shows a good electron confinement resulting in a high characteristic temperature. 相似文献
28.
Ayoub Abdelkader Mekkaoui Abderrazak Aberkouks Lahcen Fkhar Mustapha Ait Ali Larbi El Firdoussi Soufiane El Houssame 《应用有机金属化学》2020,34(11):e5917
Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction. 相似文献
29.
On the Reactivity of (−)‐(R)‐Carvone and (−)‐4aα,7α,7aβ‐Nepetalactone: Synthesis of New Heterocycles
Aziz El Mebtoul Mohamed Rouani Malika Chammache Houcine Bouidida Abdelkader Ilidrissi 《Helvetica chimica acta》2011,94(3):433-437
The 1,3‐dipolar cycloaddition of 4‐chlorobenzonitrile oxide to the unsaturated system of (?)‐(R)‐carvone occurred exclusively at C(8) to give a new isoxazoline derivative. This derivative reacts with NH2OH to yield a new heterocycle, observed for the first time. On the other hand, the addition of 4‐chlorobenzonitrile oxide to the unsaturated lactone (?)‐4aα,7α,7aβ‐nepetalactone gave, in a good yield, also a new heterocycle, again obtained for the first time. The terpenoid (?)‐(R)‐carvone and iridoid (?)‐4aα,7α,7aβ‐nepetalactone were isolated from Moroccan species Mentha viridis (L.) and Nepeta tuberosa (L.), respectively. The new heterocycles obtained were identified by combination of chromatographic and spectroscopic methods. 相似文献
30.
Bouzennada Tarek Mechighel Farid Filali Abdelkader Kolsi Lioua 《Journal of Thermal Analysis and Calorimetry》2020,141(5):1769-1784
Journal of Thermal Analysis and Calorimetry - The present study summarizes a two-dimensional (2D) numerical simulation of a phase change material (PCM) melting/solidification processes in a square... 相似文献