Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11799
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Item Multiple positive solutions for semilinear Dirichlet problems with sign-changing weight function in infinite strip domains(Nonlinear Analysis: Theory, Methods & Applications, 2009-10-01) Miyagaki, O. H.; Miotto, M. L.In this paper, existence and multiplicity results to the following Dirichlet problem −∆u + u = λf (x)|u|q−1 + h(x)|u|p−1 , u > 0, u = 0, in Ω in Ω on ∂ Ω are established, where Ω = Ω × R, Ω ⊂ RN −1 is bounded smooth domain and N ≥ 2. Here 1 < q < 2 < p < 2∗ 2∗ = N2N2 if N ≥ 3, 2∗ = ∞ if N = 2 , λ is a positive real − parameter, the function f , among other conditions, can possibly change sign in Ω , and the function h satisfies suitable conditions. The study is based on the comparison of energy levels on Nehari manifold.Item On positive solution for a class of degenerate quasilinear elliptic positone/semipositone systems(Nonlinear Analysis: Theory, Methods & Applications, 2009-01-01) Miyagaki, O. H.; Rodrigues, R. S.This paper deals with the existence and nonexistence of positive weak solutions of degenerate quasilinear elliptic systems with subcritical and critical exponents. The nonlinearities involved have semipositone and positone structures and the existence results are obtained by applying the lower and upper-solution method and variational techniques.Item Smoothing properties for the higher-order nonlinear Schrödinger equation with constant coefficients(Nonlinear Analysis: Theory, Methods & Applications, 2009-08-15) Alves, Margareth; Sepúlveda, Mauricio; Vera, OctavioWe study local and global existence and smoothing properties for the initial value problem associated to a higher-order nonlinear Schrödinger equation with constant coefficients which appears as a model for propagation of pulse in an optical fiber.Item Exponential stability in thermoviscoelastic mixtures of solids(International Journal of Solids and Structures, 2009-12-01) Alves, Margareth S.; Rivera, Jaime E. Muñoz; Sepúlveda, Mauricio A.; Villagrán, Octavio Paulo VeraIn this paper we investigate the asymptotic behavior of solutions to the initial boundary value problem for a one-dimensional mixture of thermoviscoelastic solids. Our main result is to establish the exponential stability of the corresponding semigroup and the lack of exponential stability of the corresponding semigroup.Item Exponential decay in a thermoelastic mixture of solids(International Journal of Solids and Structures, 2009-04) Alves, M .S.; Rivera, J. E. Muñoz; Quintanilla, R.In this paper, we investigate the asymptotic behaviour of solutions to the initial boundary value problem for a one-dimensional mixture of thermoelastic solids. Our main result is to establish a necessary and sufficient condition over the coefficients of the system to get the exponential stability of the corresponding semigroup. We also prove the impossibility of time localization of solutions.Item Spinning strings, black holes and stable closed timelike geodesics(International Journal of Theoretical Physics, 2009-12-01) Rosa, Valéria M.; Letelier, Patricio S.The existence and stability under linear perturbation of closed timelike curves in the spacetime associated to Schwarzschild black hole pierced by a spinning string are studied. Due to the superposition of the black hole, we find that the spinning string spacetime is deformed in such a way to allow the existence of closed timelike geodesics.