951 resultados para Microstrip lines


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It is a well known fact that librarians, as professionals go, are not among the world's most demonstrative people. I can say that with impunity because I am one. It's one thing for a man to slight his own profession; quite another when someone else presumes to do it. But given that librarians are a placid sort, just mention the phrase "intellectual freedom," or utter the word "censorship," and the usually calm demeanor of the librarian becomes as agitated as the water between Charybdis and Scylla! This article addresses three aspects of the issue of intellectual freedom and attempts to define the difference between the phrases "free speech" and "free expression." First to be explored will be the nature of intellectual freedom as defined by the American Library Association's Intellectual Freedom Manual; second, the underlying philosophy implicit in that expression; and third, an alternative to both the manual, and its philosophical presuppositions.

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SANTANA, André M.; SANTIAGO, Gutemberg S.; MEDEIROS, Adelardo A. D. Real-Time Visual SLAM Using Pre-Existing Floor Lines as Landmarks and a Single Camera. In: CONGRESSO BRASILEIRO DE AUTOMÁTICA, 2008, Juiz de Fora, MG. Anais... Juiz de Fora: CBA, 2008.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A cytogenetic study was carried out with 5-azacytidine (5-azaC) and etoposide (VP-16) in CHO-K1 and XRS-5 (mutant cells deficient for double-strand break rejoining) cell lines to verify the interaction effects of the drugs in terms of induction of chromosomal aberrations. 5-azaC is incorporated into DNA causing DNA hypomethylation, and VP-16 (inhibitor of topoisomerase 11 enzyme) is a potent clastogenic agent. Cells in exponential growth were treated with 5-azaC for I h, following incubation for 7 h, and posttreatment with VP16 for the last 3 h. In K1 cells, the combined treatments induced a significant reduction in the aberrations induced in the X and A (autosome) chromosomes, which are the main target for 5-azaC. However, in XRS-5 cells, the drug combination caused a significant increase in the aberrations induced in those chromosomes, but with a concomitant reduction in the randomly induced-aberrations. In addition, each cell line presented characteristic cell cycle kinetics; while the combined treatment induced an S-arrest in K1 cells, alterations in cell cycle progression were not found for XRS-5, although each drug alone caused a G2-arrest. The different cell responses presented by the cell lines may be explained on the basis of the evidence that alterations in chromatin structure caused by 5-aza-C probably occur to a different extent in K1 and XRS-5 cells, since the mutant cells present a typical hyper-condensed chromosome structure (especially the X- and A chromosomes), but, alternatively, 5-aza-C could induce reactivation of DNA repair genes in XRS-5 cells. Teratogenesis Carcinog. Mutagen. Suppl. 1:171-186, 2003. (C) 2003 Wiley-Liss, Inc.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The microstrip antennas are in constant evidence in current researches due to several advantages that it presents. Fractal geometry coupled with good performance and convenience of the planar structures are an excellent combination for design and analysis of structures with ever smaller features and multi-resonant and broadband. This geometry has been applied in such patch microstrip antennas to reduce its size and highlight its multi-band behavior. Compared with the conventional microstrip antennas, the quasifractal patch antennas have lower frequencies of resonance, enabling the manufacture of more compact antennas. The aim of this work is the design of quasi-fractal patch antennas through the use of Koch and Minkowski fractal curves applied to radiating and nonradiating antenna s edges of conventional rectangular patch fed by microstrip inset-fed line, initially designed for the frequency of 2.45 GHz. The inset-fed technique is investigated for the impedance matching of fractal antennas, which are fed through lines of microstrip. The efficiency of this technique is investigated experimentally and compared with simulations carried out by commercial software Ansoft Designer used for precise analysis of the electromagnetic behavior of antennas by the method of moments and the neural model proposed. In this dissertation a study of literature on theory of microstrip antennas is done, the same study is performed on the fractal geometry, giving more emphasis to its various forms, techniques for generation of fractals and its applicability. This work also presents a study on artificial neural networks, showing the types/architecture of networks used and their characteristics as well as the training algorithms that were used for their implementation. The equations of settings of the parameters for networks used in this study were derived from the gradient method. It will also be carried out research with emphasis on miniaturization of the proposed new structures, showing how an antenna designed with contours fractals is capable of a miniaturized antenna conventional rectangular patch. The study also consists of a modeling through artificial neural networks of the various parameters of the electromagnetic near-fractal antennas. The presented results demonstrate the excellent capacity of modeling techniques for neural microstrip antennas and all algorithms used in this work in achieving the proposed models were implemented in commercial software simulation of Matlab 7. In order to validate the results, several prototypes of antennas were built, measured on a vector network analyzer and simulated in software for comparison

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)