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Adriana Buica Armengol Gasull 《Journal of Mathematical Analysis and Applications》2007,331(1):443-454
We study quadratic perturbations of the integrable system , where H=(x2+y2)/2. We prove that the first three Melnikov functions associated to the perturbed system give rise at most to three limit cycles. 相似文献
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George O. Buica Christophe Bucher Jean‐Claude Moutet Guy Royal Eric Saint‐Aman Eleonora M. Ungureanu 《Electroanalysis》2009,21(1):77-86
Complexing polymer‐coated electrodes have been synthesized by oxidative electropolymerization of ethylenediamine tetra‐N‐(3‐pyrrole‐1‐yl)propylacetamide (monomer L ). The presence of four polymerizable pyrrole fragments on the same EDTA skeleton was thought to confer enhanced rigidity and controlled dimensionality to the resulting complexing materials, which were used for the electrochemical detection of Hg(II), Cu(II), Pb(II) and Cd(II) ions by means of the chemical preconcentration‐anodic stripping technique. The polyamide electrode material showed particularly a significant selectivity towards mercury ions, even in the presence of a large excess of other metal cations. Moreover, the use of imprinted polymer‐coated electrodes prepared by electropolymerization of L in the presence of metal cations turned out to significantly improve the detection limits, down to 5×10?10 mol L?1 for Hg(II) and Cu(II) species. 相似文献
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Buica George-Octavian Soare Maria-Laura Inel Georgiana Anca Razus Alexandru C. Birzan Liviu Oprisanu Alexandra Ungureanu Eleonora-Mihaela 《Journal of Solid State Electrochemistry》2016,20(11):3151-3164
Journal of Solid State Electrochemistry - The electrochemical behavior of substituted 1-phenylselanyl azulenes has been established by cyclic, differential pulse, and rotating disk electrode... 相似文献
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George-Octavian?Buica Liviu?Birzan Luisa-Roxana?Popescu Alexandru?Anton?Ivanov Eleonora-Mihaela?Ungureanu 《Journal of Solid State Electrochemistry》2016,20(2):401-411
In order to understand the essential processes/interactions between the metal ions and modified electrodes which are based on complexing polymeric films, access to thermodynamic characteristics is compulsory. The paper enlarges the information concerning the sorption of metal ions within complexing polymer films, particularly based on azulene, which can be involved in metal detection sensors. Interactions between lead(II) or cadmium(II) ions and complexing polymer films have been studied using chemical preconcentration–anodic stripping method. The films have been obtained by controlled potential electrolysis in millimolar solutions of 4-azulen-1-yl-2,6-bis(2-thienyl)pyridine (L) in acetonitrile. PolyL films affinities towards these metal ions have been quantified at different temperatures by means of sorption isotherms. Parameters for sorption of lead(II) and cadmium(II) ions within polyL films have been calculated for Freundlich, Langmuir and Redlich–Peterson isotherms. The best fit was obtained when using Langmuir isotherm. The results evidence that lead ions are better sorbed than cadmium within polyL film. Thermodynamic parameters for the chemical sorption of lead(II) and cadmium(II) ions within polyL films have been calculated. 相似文献
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Adriana Buica Aris Daniilidis 《Proceedings of the American Mathematical Society》2007,135(10):3317-3327
Existence and asymptotic stability of the periodic solutions of the Lipschitz system is hereby studied via the averaging method. The traditional dependence of on is relaxed to the mere strict differentiability of at for , giving room to potential applications for structured nonsmooth systems.
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