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61.
62.
T. Domínguez Benavides 《Journal of Mathematical Analysis and Applications》2004,291(1):100-108
Let X be a Banach space whose characteristic of noncompact convexity is less than 1 and satisfies the nonstrict Opial condition. Let C be a bounded closed convex subset of X, KC(X) the family of all compact convex subsets of X and T a nonexpansive mapping from C into KC(X) with bounded range. We prove that T has a fixed point. The nonstrict Opial condition can be removed if, in addition, T is an 1-χ-contractive mapping. 相似文献
63.
J. Barreto J.A. Rodríguez M. Perlvarez A. Morales B. Garrido C. Domínguez 《Superlattices and Microstructures》2008,43(5-6):588
This paper describes a simple method to analyze the photoluminescent characteristics of materials based on embedded light-emitting nanoclusters. Photoluminescence spectra of deposited silicon sub-oxide layers with the same composition and different thicknesses have been obtained. A saturation of the total luminescence intensity is observed with increase in thickness. By analyzing the photoluminescence spectra several optical and structural parameters can be evaluated. We thus propose a model in which the absorption of light from a nanostructure layer implies the possibility of subsequent luminescence and affects the underlying layers as well. By fitting the data to the developed model, two fundamental parameters are extracted: nanostructures absorption probability, which is independent of the emission energy and the spectra of emission probability of an excited nanostructure which fits a Gaussian shape. 相似文献
64.
The fixed point property for multivalued nonexpansive mappings 总被引:1,自引:0,他引:1
T. Domínguez Benavides 《Journal of Mathematical Analysis and Applications》2007,328(2):1471-1483
We show some properties concerning geometrical constants of Banach spaces which imply the existence of fixed points for multivalued nonexpansive mappings and we study the relationship between these properties. 相似文献
65.
66.
Gil Garrote Herminia Domínguez Juan C. Parajó 《Applied biochemistry and biotechnology》2001,95(3):195-207
Milled corncob samples were mixed with water and heated to obtain a liquid phase containing oligosaccharides, sugars, and
acetic acid as main reaction products (autohydrolysis reaction). To hydrolyze the sugar oligomers to the correspondent monomers,
sulfuric acid was added to the autohydrolysis liquors to reach 0.5–2 wt% of solution, and the reaction media were heated at
101.5–135°C. With this operational procedure, sugar solutions suitable as fermentation media (containing xylose as the major
component) were obtained. The kinetics of the posthydrolysis step was characterized on the basis of experimental data concerning
the time courses of the concentrations of xylooligosaccharides, xylose, furfural, and acetic acid. The concentrations of other
reaction byproducts (glucose or arabinose) were also measured. 相似文献
67.
I. Campos-Silva M. Ortiz-Domínguez M. Keddam N. Lpez-Perrusquia A. Carmona-Vargas M. Elías-Espinosa 《Applied Surface Science》2009,255(22):9290-9295
The growth kinetics of Fe2B layers formed at the surface of gray cast iron were evaluated in this study. The pack-boriding process was applied to produce the Fe2B phase at the material surface, and the variables included three temperatures (1173, 1223 and 1273 K) and four exposure times (2, 4, 6 and 8 h). Taking into account the growth fronts obtained at the surface of the material and the mass balance equation at the Fe2B/substrate interface, the boron diffusion coefficient on the borided phase was estimated for the range of treatment temperatures. Likewise the parabolic growth constant, the instantaneous velocity of the Fe2B/substrate interface, and the weight gain in the borided samples were established as a function of the parameters τ(t) and α(C), which are related to the boride incubation time (t0(T)) and boron concentration at the Fe2B phase, respectively. Observation of the growth kinetics of the Fe2B layers in gray cast irons suggest an optimum value of boron concentration that is in good agreement with the set of boriding experimental conditions used in this work. 相似文献
68.
69.
Gabriel Chuchani Ignacio Martín Alexandra Rotinov Rosa M. Domínguez 《国际化学动力学杂志》1990,22(12):1249-1255
Elimination kinetics of 2-bromohexane and 2-bromo-4-methylpentane in the gas phase were examined over the temperature range of 310–360°C and pressure range of 46–213 torr. The reactionsin seasoned, static reaction vessels, and in the presence of the free radical inhibitor cyclohexene, are homogeneous, unimolecular, and follow first order rate laws. The overall rate coefficients are described by the following Arrhenius equations: For 2-bromohexane, log??1(s?1) = (13.08 ± 0.70) ? (185.7 ± 8.2) kJ mol?1 (2.303RT)?1; for 2-bromo-4-methylpentane, log??1(s?1) = (13.08 ± 0.33) ? (183.4 ± 3.8) kJ mol?1 (2.303RT)?1. The electron releasing effect of alkyl groups influences the overall elimination rates. The olefin products isomerize in the presence of HBr gas until an equilibrium mixture is reached. 相似文献
70.
José María Mínguez 《Experimental Mechanics》1986,26(3):238-244
How accurate, simply supported boundary conditions can be obtained experimentally in the testing of rectangular panels subjected
to uniaxial compression has been investigated. Experimental buckling loads are obtained using the Southwell method and are
compared with theoretical predictions. Several support arrangements are examined and compared to the idealized support conditions. 相似文献