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In this article, we apply the renormalization technique, used possibly in theorical physics, for electromagnetic studying of bi dimensional fractal structures. A recurrence relation based on the auto-similar nature of structures and on the model of the surface impedance, has permitted, thanks to the convergence to a fixed point, to determine the input impedance of these structures at any scale. Though, the suggested method has been validated by calculus of one-dimensional structures (Iris de Cantor) it may be applied easily to the analysis of planar circuits as the Sierpensky antenna. 相似文献
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JL Van Laethem M Cremer MO Peny M Delhaye J Devière 《Canadian Metallurgical Quarterly》1998,43(6):747-751
Microcapsules are used for the formulation of drug controlled release and drug targeting dosage forms. Encapsulated hydrophobic drugs are often applied as their solutions in plant oils. The uptake of the oils in the complex coacervate microcapsules can be improved by the addition of surfactants. In this study, soybean, olive and peanut oils were chosen as the representatives of plant oils. The well characterized complex coacervation of gelatin and acacia has been used to produce the microcapsules. The amount of encapsulated oil has been determined gravimetrically. The encapsulation of the oils was high (75-80%). When the surfactants with HLB values from 1.8 to 6.7 were used, the amount of encapsulated oil was high (65-85%). A significant decrease of the oil content in the microcapsules was found when Tween 61 with HLB = 9.6 had been added into the mixture. No oil was found inside the microcapsules from the coacervate emulsion mixture containing Tween 81 (HLB = 10) and Tween 80 (HLB = 15), respectively. The results of the experiment confirm the dependence of hydrophobic substance encapsulation on the HLB published recently for Squalan. 相似文献
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Reviews the book, Psychologie de la famille by Monique V. G. Morval (1985). Morval presents a book with two views: the first looks at the axis of the family in light of systemic approaches and the second centers on the cycle of family life. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Hybrid Approach for Addressing Uncertainty in Risk Assessments 总被引:3,自引:0,他引:3
Dominique Guyonnet Bernard Bourgine Didier Dubois Hélène Fargier Bernard C?me Jean-Paul Chilès 《Canadian Metallurgical Quarterly》2003,129(1):68-78
Parameter uncertainty is a major aspect of the model-based estimation of the risk of human exposure to pollutants. The Monte Carlo method, which applies probability theory to address model parameter uncertainty, relies on a statistical representation of available information. In recent years, other uncertainty theories have been proposed as alternative approaches to address model parameter uncertainty in situations where available information is insufficient to identify statistically representative probability distributions, due in particular to data scarcity. The simplest such theory is possibility theory, which uses so-called fuzzy numbers to represent model parameter uncertainty. In practice, it may occur that certain model parameters can be reasonably represented by probability distributions, because there are sufficient data available to substantiate such distributions by statistical analysis, while others are better represented by fuzzy numbers (due to data scarcity). The question then arises as to how these two modes of representation of model parameter uncertainty can be combined for the purpose of estimating the risk of exposure. This paper proposes an approach (termed a hybrid approach) which combines Monte Carlo random sampling of probability distribution functions with fuzzy calculus. The approach is applied to a real case of estimation of human exposure, via vegetable consumption, to cadmium present in the surficial soils of an industrial site located in the north of France. The application illustrates the potential of the proposed approach, which allows the uncertainty affecting model parameters to be represented in a way that is consistent with the information at hand. Also, because the hybrid approach takes advantage of the “rich” information provided by probability distributions, while retaining the conservative character of fuzzy calculus, it is believed to hold value in terms of a “reasonable” application of the precautionary principle. 相似文献
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