Fractal Structures
Mostrando 1-12 de 24 artigos, teses e dissertações.
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1. Broadband Antennas Based on the Double Moebius Strip
Abstract The family of new antenna designs based on the double Moebius strip principle is proposed in this article. Three possible options of the power supply port location had been reviewed in this respect: the cut external strip with the signal port located directly in the cut area is used; the continuous rings without discontinuities are applied, with the
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Design and Performance Study of Single and Multi-Layered Fractal Based Miniaturized Patch Antennas for 2.4 GHz Applications
Abstract The design and characterization of single and multi-layered miniaturized microstrip antennas resonating at 2.4 GHz are proposed. The miniaturization is accomplished by fractal Defected Ground Structure (DGS). The DGS used for miniaturization is a Modified Minkowski Fractal DGS (M-MFDGS). The proposed size reduction process with M-MFDGS follows the s
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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3. A Novel Fractal Multi-band Frequency Selective Surface
Abstract In this paper, a new multiband fractal frequency selective surface (MF-FSS) is proposed. The work presents a new fractal design methodology for FSSs with Swastika fractal patch elements. The proposed MF-FSS includes periodic arrays of metallic patches, printed on a single layer substrate. The structure parametric analysis is carried out in terms of
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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4. Insights on Structuration of Peroxotungstic Acid in Aqueous Media
Recent studies on tungsten oxide preparation are mainly motivated by its applications in smart windows, energy harvesting and, recently, in cancer therapy. Peroxotungstic acid (PTA) is an important precursor to obtain tungsten oxide in an environmentally-friendly way, through the colloidal synthesis in aqueous media. Despite giving chemically pure products,
J. Braz. Chem. Soc.. Publicado em: 2019-04
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5. An Investigation on Morphology and Fractal Dimension of Diesel and Diesel-Biodiesel Soot Agglomerates
In this study, it is reported the fractal dimension and morphology of ultrafine particles emitted by a diesel engine run with B4, B50, and B100. Transmission electron micrographs evidenced two main groups of particles with characteristic and distinct morphological behaviors: (i) particle agglomerate structures self-organized within a fractal-like geometry, a
J. Braz. Chem. Soc.. Publicado em: 2017-08
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6. Multiband frequency selective surfaces with a modified multifractal cantor geometry
Self-affine property of a modified multifractal Cantor geometry is exploited to design frequency selective surfaces (FSS) with multiband response. The main advantage of the proposed structure is to design multiband FSS with multiple frequency ratios between the adjacent bands and easily-built structures. In addition, the proposed structure increases the degr
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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7. Study of different shape Electromagnetic Band Gap (EBG) structures for single and dual band applications
In this paper, single and dual band EBG structures for wider bandwidth are proposed. In each of the discussed EBGs, a metallic patch of regular geometry is chosen for the unit element. The patch is further modified by cutting slots to get extra inductance and capacitance which results into lower cut-off frequency and larger bandwidth. The proposed EBG struct
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-06
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8. Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites
Nanocomposites of poly (methyl methacrylate) (PMMA) and carbon nanotubes have a high potential for applications where conductivity and low specific weight are required. This piece of work concerns investigations of the level of dispersion and morphology on the electrical properties of in situ polymerized nanocomposites in different concentrations of multi-wa
Mat. Res.. Publicado em: 09/05/2014
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9. The role of nonequilibrium thermo-mechanical statistics in modern technologies and industrial processes: an overview
The nowadays notable development of all the modern technology, fundamental for the progress and well being of world society, imposes a great deal of stress in the realm of basic Physics, more precisely on Thermo-Statistics. We do face situations in electronics and optoelectronics involving physical-chemical systems far-removed-from equilibrium, where ultrafa
Brazilian Journal of Physics. Publicado em: 2010-03
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10. Aspectos dinâmicos de espalhamento caótico clássico / Dynamical aspects of classical scattering
In this thesis we study different scattering systems with chaos. Chaotic scattering, present in a large variety of physical systems, is a type of transient chaos. While the phase-space of such systems is unbounded, irregular motion occurs only in a bounded area, called the scattering region. Still, any (nontrivial) scattering function relating initial condit
Publicado em: 2009
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11. Geometry, dynamics and fractals
Consider a collection of elastic wires folded according to a given pattern induced by a sequence of fractal plane curves. The folded wires can act as elastic springs. Therefore it is easy to build up a corresponding sequence of simple oscillators composed by the elastic springs clamped at one end and carrying a mass at the opposite end. The oscillation perio
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2008-03
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12. Dois problemas em análise de formas de estruturas de ramificação / Two Problems in Shape Analysis of Branching Structures
O presente texto descreve métodos e apresenta resultados do projeto de pesquisa de mestrado intitulado "Dois Problemas em Análise de Formas de Estruturas de Ramificação". Ambos os problemas abordados estão relacionados às sub-áreas da Análise de Formas denominadas Caracterização e Descrição de Formas. O primeiro problema consiste na investigaçã
Publicado em: 2008