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551.
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Rodrigo D. Euzébio Jaume Llibre Claudio Vidal 《Mathematical Methods in the Applied Sciences》2015,38(17):4289-4299
We characterize the values of the parameters for which a zero‐Hopf equilibrium point takes place at the singular points, namely, O (the origin), P+, and P? in the FitzHugh–Nagumo system. We find two two‐parameter families of the FitzHugh–Nagumo system for which the equilibrium point at the origin is a zero‐Hopf equilibrium. For these two families, we prove the existence of a periodic orbit bifurcating from the zero‐Hopf equilibrium point O. We prove that there exist three two‐parameter families of the FitzHugh–Nagumo system for which the equilibrium point at P+ and at P? is a zero‐Hopf equilibrium point. For one of these families, we prove the existence of one, two, or three periodic orbits starting at P+ and P?. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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On the Origin of the Inertial Force and Gravitation 总被引:1,自引:0,他引:1
Jaume Giné 《International Journal of Theoretical Physics》2011,50(2):607-617
In this paper we study the state of the art of the inertia theory, the gravity and the cosmology constant and their current
open problems. 相似文献
555.
Núria Crivillers Marta Mas-Torrent Stefan T Bromley Klaus Wurst Jaume Veciana Concepció Rovira 《Chemphyschem》2007,8(10):1565-1571
We study the assemblies that tetra(carbomethoxy)tetrathiafulvalene (TCM-TTF) forms in solution and when deposited on a surface depending on intermolecular interactions and on the interactions with the substrate and the solvent. Its organization on graphite and mica substrates was studied by atomic force microscopy, and different molecular assemblies were observed depending on the prevailing interactions. The promotion of molecule-molecule interactions gave rise to the formation of molecular fibers. The investigation of the influence of the solvent-molecule interactions on TCM-TTF molecular organizations was carried out by UV/Vis spectroscopy, and a new TCM-TTF polymorph was obtained by changing the nature of the solvent. Finally, an explanation for all these phenomena, supported by computational modeling, is put forward. 相似文献
556.
This article deals with an example of nonlinear control systems and the interlacing between a biochemical system, the mathematical model and the constrains derived from the discrete implementation of a continuous control policy. The theory is developed on a simplified model of a bioreactor to be regulated, and the sliding mode control is presented as a robust control technique. The biological interpretation of the results derived from the mathematical model is pointed out, especially of those more closely involved with the implementation, as is the case of sample period, which seems to be very enough with respect to the minimum time needed for sample analysis. 相似文献
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Treatment of 3-aminobenzo-as-triazines with bromoacetaldehyde ethylene acetal give linear tricyclic imidazobenzo-as-triazines, where 3-amino-7-methylbenzo-as-triazine 1-oxide yields the angular isomer. The structures of these compounds have been established by comparing their nmr spectra to those of pyrazolo [5,1-c]- and s-triazolo[5,1-c]benzo-as-triazines obtained form the appropriate azo derivatives by intramolecular cyclization. 相似文献