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31.
Chouhaïd Souissi 《Archiv der Mathematik》2017,109(1):73-82
We show, under an iterative condition, generalizing that of Ambrosetti–Rabinowitz and using a variational method, the existence of a T-periodic solution for the autonomous superquadratic second order Hamiltonian system with even potential for any prescribed period \(T>0\). Moreover, under a certain symmetry condition, such a solution possesses T or T / 3 as its minimal period.
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$$\begin{aligned} \ddot{z} +V'(z)=0, \qquad z\in \mathbb R^N, \qquad N\in \mathbb N^* \end{aligned}$$
32.
Stéphane Bouchonnet Sophie Bourcier Yasmine Souissi Christophe Genty Michel Sablier Pascal Roche Véronique Boireau Valérie Ingrand 《Journal of mass spectrometry : JMS》2012,47(4):439-452
The degradation of the chloracetamide herbicide acetochlor has been studied under simulated ozonation treatment plant conditions. The degradation of acetochlor included the formation of several degradation products that were identified using GC/ion‐trap mass spectrometry with EI and CI and HPLC/electrospray‐QqTOF mass spectrometry. Thirteen ozonation products of acetochlor have been identified. Ozonation of the deuterated herbicide combined to MSn and high‐resolution mass measurement allowed effective characterization of the degradation products. At the exception of one of them, the product B (2‐chloro‐2', ethyl‐6', methyl‐acetanilide), none of the identified degradation products has been already reported in the literature. Post‐ozonation kinetics studies revealed that the concentrations of most degradation products evolved noticeably with time, particularly during the first hours following the ozonation treatment. This raises concerns about the fate of degradation products in the effluents of treatment plants and suggests the need for a better control on these products if their toxicity was demonstrated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
33.
A. Souissi C. Sartel G. Amiri A. Meftah A. Lusson P. Galtier V. Sallet M. Oueslati 《Solid State Communications》2012,152(18):1729-1733
We present Raman scattering study of wurtzite ZnO nanowires deposited by metal–organic chemical vapor deposition (MOCVD) on (0001) sapphire. It is shown that the misorientation of the nanowires, i.e. the inclination with respect to the vertical direction, mixes A1 and E1 Raman modes, giving rise to new modes for which the propagation directions make various angles with the C-axis of ZnO nanowires. Two particular bands depending on the tilt of the nanowires are observed at 400 and 585 cm?1. They are attributed to TO and LO quasi-phonons, and explained using Loudon's model. Morphological information of the nanowires was extracted and an average orientation of nanowires is calculated. 相似文献
34.
Bouchonnet S Bourcier S Souissi Y Genty C Sablier M Roche P Boireau V Ingrand V 《Journal of mass spectrometry : JMS》2012,47(4):439-452
The degradation of the chloracetamide herbicide acetochlor has been studied under simulated ozonation treatment plant conditions. The degradation of acetochlor included the formation of several degradation products that were identified using GC/ion-trap mass spectrometry with EI and CI and HPLC/electrospray-QqTOF mass spectrometry. Thirteen ozonation products of acetochlor have been identified. Ozonation of the deuterated herbicide combined to MS(n) and high-resolution mass measurement allowed effective characterization of the degradation products. At the exception of one of them, the product B (2-chloro-2', ethyl-6', methyl-acetanilide), none of the identified degradation products has been already reported in the literature. Post-ozonation kinetics studies revealed that the concentrations of most degradation products evolved noticeably with time, particularly during the first hours following the ozonation treatment. This raises concerns about the fate of degradation products in the effluents of treatment plants and suggests the need for a better control on these products if their toxicity was demonstrated. 相似文献
35.
Metal organic chemical vapor deposition (MOCVD) has been used to grow vanadium-doped GaN (GaN:V) on c-sapphire substrate using VCl4 as the V source. The as-grown GaN:V exhibited a saturated magnetic moment (Ms) of 0.28 emu/cm3 at room temperature. Upon high-temperature annealing treatment at 1100 °C for 7 min under N2 ambient, the Ms of the GaN:V increased by 39.28% to 0.39 emu/cm3. We found that rapid thermal annealing leads to a remarkable increase in surface roughness of the V-doped GaN as well as the electron concentration. The annealing also leads to a significant increase in the Curie temperature (TC), we have identified Curie temperatures about 350 K concluded from the difference between the field-cooled and zero-field-cooled magnetizations. Structure characterization by x-ray diffraction indicated that the ferromagnetic properties are not a result of secondary magnetic phases. 相似文献
36.
S. Ktifa A. Souissi F. Saadallah V. Sallet M. Oueslati N. Yacoubi 《Applied Physics A: Materials Science & Processing》2014,114(2):559-563
ZnO thin films were grown by metal-organic chemical vapor deposition on Zn- and O-polar surfaces of ZnO substrate. The effect of Zn- and O-polar substrate on the surface morphology and opto-thermal proprieties has been studied. Hall-measurements were used to determine the carrier concentration of the deposited films. Photothermal deflection spectroscopy (PDS) was used to determine the optical absorption spectrum and the gap energy by comparing experimental amplitude of the photothermal signal to the corresponding theoretical one. Thermal conductivity and diffusivity were also deduced from the photothermal deflection measurements. The found values were very low due to the thermal resistivity of the layer–substrate interface. 相似文献
37.
Souha Kammoun Hajer Souissi Ramzi Maalej Mohamed Dammak Mohamed Kamoun 《Journal of luminescence》2009,129(5):411-415
The experimental studies have provided evidence of the occurrence of transitions from the 3T1g(3F) ground state to the crystal-field levels 3T2g(3F), 3T1g(3P) and 3A2g(3F) for the V3+ centres in Al2O3 crystal; and from the 3A2g(3F) ground state to the crystal-field levels 3T2g(3F), 3T1g(3F) and 3T1g(3P) for the Ni2+ centres in LiNbO3 crystal (levels are assigned to irreps of the Oh point symmetry group). Using the experimental spectroscopic data, theoretical calculations of the crystal-field levels of V3+:Al2O3 and Ni2+:LiNbO3 are carried out based on the Racah theory. The observed crystalline-field splittings of the V3+ and Ni2+ terms were accounted for using a C3 symmetry Hamiltonian. The spin-orbit interaction was taken into account in this work. The Racah, crystal-field and spin-orbit parameters, which fit experimental and theoretical energy levels, have been reliably obtained. A good agreement between the theoretical and experimental results for the energy levels of V3+:Al2O3 and Ni2+:LiNbO3 has been obtained. 相似文献
38.
Boujemâa Achchab Abdellatif Agouzal Khalid Bouihat Adil Majdoubi Ali Souissi 《Numerical Methods for Partial Differential Equations》2017,33(1):218-240
In this article we study a projection‐stabilized nonconforming finite element discretization of the Stokes problem. We present a priori error analysis and give a recovery‐based a posteriori error estimator for the considered problem. Numerical results illustrate the theoretical performance of the error estimator. © 2016 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 33: 218–240, 2017 相似文献
39.
Plackett–Burman experimental design was carried out in order to optimize the experimental conditions of polyaniline (PANI) electrodeposition for Cu10Sn bronze alloy corrosion protection in neutral aerated aqueous 0.5 M chloride medium. Seven factors including scan rate, aniline concentration, hydroxyl ions concentration, cycle number, nature of solvent, starting potential, and final potential for the cyclic voltammetry study were considered. The experimental responses were Ecorr, βa, βc, B, Jcorr, Rp, the percentage of protection efficiency and the coatings porosities. A linear mathematical model was applied to estimate the coefficients related to the different experimental responses. The significance of the different factors was evaluated through Pareto analysis. The optimum conditions for PANI electrodeposition were estimated and discussed. PANI coatings were concluded to offer protection efficiency higher than 90% for Cu10Sn bronze alloy. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
40.
Sarah Coffinet Ahmad Rifai Christophe Genty Yasmine Souissi Sophie Bourcier Michel Sablier Stéphane Bouchonnet 《Journal of mass spectrometry : JMS》2012,47(12):1582-1593
Aqueous solutions of metolachlor and metolachlor‐d6 were photolyzed with UV‐visible radiations. The structures of 15 by‐products of metolachlor were determined through gas chromatography‐mass spectrometry analyses using electron and chemical ionization combined with multistage mass spectrometry. The photolysis by‐products of metolachlor resulted mainly from dehalogenation and hydroxylation, in some cases accompanied by cyclization. In silico tests for toxicity prediction showed that the toxicity of some photolysis products is expected to be greater than that of metolachlor. Persistence studies showed that the by‐product relative abundances vary in large amounts with the irradiation time. The post‐photolysis evolution of the solution was also studied, in order to determine the persistence of the main by‐products. It allowed to establish that most of the by‐products can be found more than 12 h after the end of the photolysis, which is of a great concern as treated water is generally available for consumption only a few hours after treatment in most of industrial processes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献