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991.
992.
G. Gonçalves P. Barquinha L. Raniero R. Martins E. Fortunato 《Thin solid films》2008,516(7):1374-1376
In this work we studied indium zinc oxide (IZO) thin films deposited by r.f. magnetron sputtering at room temperature. The films were annealed at high temperature (1100 K) in vacuum, and the oxygen exodiffusion was monitored in-situ. The results showed three main peaks, one at approximately 600 K, other at approximately 850 K and the last one at 940 K, which are probably from oxygen bonded in the film surface and in the bulk, respectively. The initial amorphous structure becomes microcrystalline, according to the X-ray diffraction. The electrical conductivity of the films decreases (about 3 orders of magnitude), after the annealing treatment.This behavior could be explained by the crystallization of the structure, which affects the transport mechanism. Apart from the changes in the material structure, a small variation was observed on the absorption coefficient. 相似文献
993.
Elisabete Almeida Dulcínea Santos Jorge Uruchurtu 《Progress in Organic Coatings》1999,37(3-4):131-140
Among recently developed waterborne coatings, epoxy and acrylic based coatings have a special place. To study this kind of anticorrosive coatings, use is normally made of natural exposure and laboratory tests. The literature has recently reported that the salt spray test is not suitable for selecting/studying anticorrosive waterborne coatings. In this paper, the authors present the main results obtained in an experimental study involving laboratory tests and natural exposure in two atmospheric test sites of different corrosivity categories. The natural exposure and accelerated tests are complemented by other measurements in the laboratory, involving water uptake, adhesion and electrochemical measurements, to understand the anticorrosive performance of the paint systems under study. As accelerated tests, salt spray and prohesion were used. Indirect measurements of adhesion were made using cross-cut and pull-off tests. Electrochemical impedance spectroscopy (EIS) and noise (EN) were used for electrochemical characterization. The study concludes that the best anticorrosive behaviour was shown by epoxy-polyamide paint systems, including zinc-rich primers. The correlation between the results of salt spray and natural exposure in marine test sites was significantly better than that obtained using the prohesion test. The electrochemical results showed that it is very important to pay special attention when interpreting this kind of results. 相似文献
994.
995.
María C. Caracoche Jorge A. Martinez Patricia C. Rivas Fernanda Andreola Federica Bondioli Anna Maria Ferrari Tiziano Manfredini 《Journal of the American Ceramic Society》2008,91(7):2357-2359
This paper deals with the phase stability of an aqueous suspension of tetragonal Zr0.9 Pr0.1 O2 (20 wt%/vol%) at room temperature as a function of the aging time. The suspension is investigated in situ using the highly localized Perturbed Angular Correlations technique. The results indicate that an almost fully reversible degradation process toward monoclinic zirconia takes place through a first-order reaction of rate constant k =0.7 day−1 . Two successive diffusion mechanisms are observed that are interpreted as OH− ions' migration in the grain surface and then, as proton defects' diffusion into the bulk. 相似文献
996.
Replacement strategies to preserve useful diversity in steady-state genetic algorithms 总被引:1,自引:0,他引:1
In this paper, we propose a replacement strategy for steady-state genetic algorithms that considers two features of the candidate chromosome to be included into the population: a measure of the contribution of diversity to the population and the fitness function. In particular, the proposal tries to replace an individual in the population with worse values for these two features. In this way, the diversity of the population becomes increased and the quality of the solutions gets better, thus preserving high levels of useful diversity. Experimental results show the proposed replacement strategy achieved significant performance for problems with different difficulties, with regards to other replacement strategies presented in the literature. 相似文献
997.
998.
We study the contribution of the most important processes leading to the creation of excited states of Cl14+ ions from the ground configurations of Cl ions in an Electron Cyclotron Resonance Ion Source (ECRIS), which lead to the emission of K X-ray lines. Theoretical values for inner-shell excitation, K and KL ionization cross-sections, and energies and transition probabilities for the de-excitation processes are calculated in the framework of the Multi-Configuration Dirac-Fock (MCDF) method. With reasonable assumptions about the electron energy distribution, a theoretical Kα X-ray spectrum is obtained, which reproduces closely a recent experimental result. 相似文献
999.
1000.
Manuel Evaristo Tomas Polcar Albano Cavaleiro 《International Journal of Mechanics and Materials in Design》2008,4(2):137-143
W-S-C films were deposited by non-reactive sputtering from a carbon target incrusted with WS2 pellets in the eroded zone. This process allows depositing coatings with a wide range of compositions, with a precise control
of their carbon content. Before the deposition, a Ti interlayer was interposed between the film and the substrate to improve
the final adhesion. The carbon content in W-S-C system was varied from 29 at.% to 70 at.%, which led to an hardness enhancement
from 4 GPa up to 10 GPa where the maximum hardness was reached in films with a carbon content between 40 at.% and 50 at.%.
The tribological behaviour of the coatings was evaluated by pin-on-disk testing, in environments with different humidity levels.
Generally, the tribological performance of W-S-C coatings in environments with moderate to high humidity is better for coatings
with high carbon content. Friction coefficients, as 0.05 or lower could be reached at low humidity ranges (<7%) to all compositions.
However, for higher humidity values, friction coefficient increased up to 0.30 in the W-S-C film with low carbon content whereas
it was kept approximately constant for the others compositions. 相似文献