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41.
42.
M. Gadella M. L. Glasser L. M. Nieto 《International Journal of Theoretical Physics》2011,50(7):2144-2152
We study a one-dimensional singular potential plus two types of regular interactions: constant electric field and harmonic
oscillator. In order to search for the bound state energies, we shall use the Lippman-Schwinger Green function technique.
Another direct method will be mentioned for the harmonic oscillator. In the electric field case the unique bound state coincides
with that found in an earlier study as the field is switched off. For non-zero field the ground state is shifted and positive
energy “quasibound states” appear. The harmonic oscillator demonstrates the general result that for a symmetric potential
the odd states are not altered whereas the even states energies are lowered or raised accordingly as the delta perturbation
is attractive or repulsive. No states are created or annihilated. 相似文献
43.
A pneumatic suspension that can adapt itself to the incoming vibration is presented in this paper. A switching control strategy between two different configurations is proposed and studied. The objective is to avoid undesirable resonant frequencies. The control procedure is based on the pre-knowledge of the incoming vibration frequency, and when this frequency is unknown, a very efficient prediction technique is used. The results show that the adaptable suspension has improved performance as compared to any of its passive counterparts. The transient response when switching typically takes less than three cycles and does not hinder the suspension performance. 相似文献
44.
We introduce a new metric in the space of fuzzy polynucleotides. 相似文献
45.
J. Nieto T. Oswald F. Blanco Joao B. P. Soares Benjamin Monrabal 《Journal of Polymer Science.Polymer Physics》2001,39(14):1616-1628
The effect of molecular weight and long‐chain branching on the crystallization analysis fractionation (CRYSTAF) of ethylene homopolymers was investigated. Several ethylene homopolymers were prepared with different molecular weights and levels of long‐chain branching to isolate these effects from the dominant effect of comonomer content on crystallizability measured by CRYSTAF. Molecular weight effects might be significant for samples with number‐average molecular weights below 5000, but this effect can be corrected if terminal methyl groups are taken into account. Long‐chain branching has only a very small effect on the CRYSTAF profile of the samples investigated in this study. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1616–1628, 2001 相似文献
46.
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48.
Roberto Floreanini Javier Negro Luis Miguel Nieto Luc Vinet 《Letters in Mathematical Physics》1996,36(4):351-355
Discrete versions of the heat equation on two-dimensional uniform lattices are shown to possess the same symmetry algebra as their continuum limits. Solutions with definite symmetry properties are presented. 相似文献
49.
Existence and Uniqueness of Fixed Point in Partially Ordered Sets and Applications to Ordinary Differential Equations 总被引:1,自引:0,他引:1
We prove some fixed point theorems in partially ordered sets, providing an extension of the
Banach contractive mapping theorem. Having studied previously the nondecreasing case, we consider
in this paper nonincreasing mappings as well as non monotone mappings. We also present some
applications to first–order ordinary differential equations with periodic boundary conditions, proving
the existence of a unique solution admitting the existence of a lower solution.
Research partially supported by Ministerio de Educación y Ciencia and FEDER, Project MTM2004-06652-C03-01, and by Xunta de
Galicia and FEDER, Projects PGIDIT02PXIC20703PN and PGIDIT05PXIC20702PN 相似文献
50.
We study a periodic boundary value problem for a nonlinear ordinary differential equation of second order when the nonlinearity is given by a Carathéodory function. We generalize the monotone iterative method to cover the fully nonlinear case. 相似文献