排序方式: 共有79条查询结果,搜索用时 46 毫秒
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Rodolphe Alchaar Houssin Makhlouf Nadine Abboud Sophie Tingry Radhouane Chtourou Matthieu Weber Mikhael Bechelany 《Journal of Solid State Electrochemistry》2017,21(10):2877-2886
A new process enabling the synthesis of zinc oxide (ZnO) and Al-doped ZnO nanowires (NWs) for photosensing applications is reported. By combining atomic layer deposition (ALD) for the seed layer preparation and electrodeposition for the NW growth, high-quality ZnO nanomaterials were prepared and tested as ultraviolet (UV) sensors. The obtained NWs are grown as arrays perpendicular to the substrate surface and present diameters between 70 and 130 nm depending on the Al doping, as seen from scanning electron microscopy (SEM) studies. Their hexagonal microstructure has been determined using X-ray diffraction and Raman spectroscopy. An excellent performance in UV sensing has been observed for the ZnO NWs with low Al doping, and a maximal photoresponse current of 11.1 mA has been measured. In addition, initial studies on the stability have shown that the NW photoresponse currents are stable, even after ten UV on/off cycles. 相似文献
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Melamine salt of pentaerythritol phosphate kaolin (MPPK) was synthesized by the reaction of pentaerythritol phosphate with kaolin (K) and melamine. The structure of MPPK was confirmed by EDXS, 1H NMR, FTIR, and XRD. MPPK was blended with polypropylene (PP) at different loading levels. Thermogravimetric analysis (TGA) results showed that MPPK improved the thermal stability of PP at high temperatures in all PP composites. Vertical burning rate test manifested that PP composites can achieve V0 at 20% and 25% MPPK loading levels. Cone calorimeter data exhibited that addition of 25% MPPK to PP reduced peak of heat release rate (pHRR) and total heat release (THR) by 86% and 76% and increased the char residue after test to 67%. The results of PP/25% MPPK composite were compared with the data obtained from PP containing 25% K and 25% of traditional intumescent flame retardant composed of melamine phosphate (MP), pentaerythritol (PE), and K. The outcomes indicated that MPPK was more efficient in flame retardancy than the other systems. The digital photographs and SEM images for char residue demonstrated that MPPK succeeded in forming cellular and coherent char layer on the PP surface. The main advantage of adding 25% MPPK to PP was its ability to preserve nearly the inner half of the sample without burning after cone calorimeter test. 相似文献
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In this paper we study a four-dimensional linear center. Based on the averaging theory, we investigate the existence of limit cycles of the system. 相似文献
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A nonlinear inequality and application to global asymptotic stability of perturbed systems 下载免费PDF全文
The goal of this work is to present a new nonlinear inequality which is used in a study of the Lyapunov uniform stability and uniform asymptotic stability of solutions to time‐varying perturbed differential equations. New sufficient conditions for global uniform asymptotic stability and/or practical stability in terms of Lyapunov‐like functions for nonlinear time‐varying systems is obtained. Our conditions are expressed as relation between the Lyapunov function and the existence of specific function which appear in our analysis through the solution of a scalar differential equation. Moreover, an example in dimensional two is given to illustrate the applicability of the main result. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Makhlouf Amoura Cécile Roux Sylvie Masse Nathalie Steunou Thibaud Coradin 《Comptes Rendus Chimie》2010,13(1-2):52-57
Zirconium oxyhydroxide nanoparticles prepared by an aqueous route were evaluated for Escherichia coli bacteria encapsulation. A low viability rate was measured 24 hours after immobilization that could be attributed to nanoparticle cytotoxicity. Moreover, the presence of glycerol, a long-term cell-preserving molecule, hindered gel formation, probably due to its adsorption on the nanoparticle surface. A comparison with boehmite and ferrihydrite gels previously synthesized following a similar aqueous colloidal route suggests that the generalization of this method will rely on a careful control of the nanoparticle surface reactivity and may require surface chemical modification. 相似文献
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Aly Ashraf A. Hassan Alaa A. Mohamed Nasr K. El-Shaieb Kamal M. Makhlouf Maysa M. Bräse Stefan Nieger Martin 《Research on Chemical Intermediates》2019,45(2):613-631
Research on Chemical Intermediates - The reaction of N-substituted hydrazinecarbothioamides with both 2-(bis(methylthio)methylene)malononitrile and ethyl 2-cyano-3,3-bis(methylthio)acrylate... 相似文献
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Hala Samaha Nathalie Chahine Anatoly Petrovich Sobolev Luigi Menghini Hassane Makhlouf 《Molecules (Basel, Switzerland)》2021,26(16)
Despite the beneficial health properties shown by Lebanese saffron, its qualitative and quantitative composition has never been investigated before. In the present study, NMR spectroscopy, together with antioxidant activity assays, were applied to evaluate the chemical composition of saffron samples of different geographical origins (Lebanon, Italy, Iran, and India) and to categorize the Lebanese saffron for the first time. The distinction between Lebanese saffron and that produced in other countries was attributed to its higher linolenic and linoleic fatty acids, glucose and picrocrocin contents. Moreover, spices produced in three different regions of the Lebanese territory have been clearly differentiated. Saffron cultivated in the Qaa region displayed a high glucose, fatty acids and polyphenols content, whereas Hermel saffron exhibited the largest rate of picrocrocin and glycosylated carotenoids. Finally, samples from Baalbeck showed lower rates for the majority of metabolites. Moreover, Lebanese saffron showed a high antioxidant activity in ABTS and DPPH assays. A low dose of saffron extract (10 µg/mL) inhibited the growth of human lung adenocarcinoma cells, probably due to the high polyphenolic content. This study highlights the quality and peculiarity of Lebanese saffron cultivated in Northern Beqaa district and allows for a good discrimination between spices produced in relatively close territory. 相似文献
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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
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