Refractive Index
Mostrando 1-12 de 180 artigos, teses e dissertações.
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1. Frequency Reconfigurable Near-Zero Refractive Index Material for Antenna Gain Enhancement Applications
Abstract In this paper, a planar near-zero refractive index material (NZRIM) consisting of an outer loop with four symmetrical quarter-rings is proposed. The quarter-rings are connected to the outer loop by two symmetrical microstrip lines on the opposite side. The backside of the substrate has mutually central split microstrip lines. By loading adjustable c
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Radially Periodic Metasurface Lenses for Magnetic Field Collimation in Resonant Wireless Power Transfer Applications
Abstract In this paper, a new procedure and topology of magnetic metasurface lens are proposed for improving the performance of Resonant Wireless Power Transfer systems. Firstly, three subwave-length unit cells are optimized in order to get negative magnetic permeability in the same frequency, each one with a different refractive index, and they are experime
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. A High Gain Super Wideband Metamaterial Based Antenna
Abstract The paper proposes a high gain, metamaterial based super wideband (SWB) antenna. The SWB antenna has two inverted U slots which are responsible for two notches at 3.5 GHz and 5.5 GHz frequencies. A flower-shaped slot is etched from the radiator to obtain the SWB characteristics. The super wideband antenna has dimensions of 30×35 ×1.5 mm3 with FR4
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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4. Structure-Physical Properties Relationship of Eutectic Solvents Prepared from Benzyltriethylammonium Chloride and Carboxylic Acids
Deep eutectic solvents (DESs) have attracted the attention of the researchers as alternative solvents due to desirable properties such as easy preparation and high thermal stability. In this work, it was reported the preparation of five DESs from benzyltriethylammonium chloride (BTEAC) as quaternary ammonium salt (QAS) and carboxylic acids (oxalic, malonic o
J. Braz. Chem. Soc.. Publicado em: 2021-03
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5. Optical Fiber Coupler Analysis Using Daubechies Wavelets
Abstract This article presents the theoretical analysis of a signal coupling between a proposed Photonic Crystal Fiber (PCF) and a Conventional Fiber with Step Index (CFSI) system. In this analysis, the Finite Element Method (FEM) and Beam Propagation Method (BPM) are applied together with Daubechies wavelets as basis function and described in the mathematic
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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6. Effect of Metamaterial Cells Array on a Microstrip Patch Antenna Design
Abstract In this paper, a microstrip patch antenna (MPA) design was developed to verify the performance of a metamaterial cell array (MTM) Capacitive Loaded Loop (CLL) immersed in the substrate. The metamaterial was obtained from metal laminates designed inside a dielectric material, with dimensions carefully calculated to have the effective negative permitt
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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7. Determination of Methanol in Gasoline and Ethanol Fuels by High-Performance Liquid Chromatography
Gasoline and ethanol fuels have been adulterated with methanol in Brazil. Methanol is not permitted in concentrations greater than 0.5 vol% due its toxicity but its lower price stimulates the adulteration. A new approach for quantitative analysis of methanol in gasoline and ethanol fuels is reported employing high-performance liquid chromatography coupled wi
J. Braz. Chem. Soc.. Publicado em: 2020-05
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8. Tucum-do-Pantanal (Bactris setosa Mart.): Physicochemical Characterization of Almonds, Press Cake and Crude Oil
Abstract Brazil has high diversity of native fruits with high nutritional and biochemical value. Bactris setosa Mart. (tucum-do-Pantanal) stands out by its oil-rich almond. This study aimed to determine the physicochemical characteristics of tucum-do-Pantanal almond and its by-products: press cake and crude oil. The almond of tucum-do-Pantanal had total wei
Braz. arch. biol. technol.. Publicado em: 25/11/2019
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9. Design of Three-Layer Antireflection Coating for High Reflection Index Lead Chalcogenide
Antireflection coatings (ARC), not only reduce the reflection of the incident radiation but also protect the surface from environmental degradations. In present study, three- layer design was theoretically calculated and experimentally realized on the surface of lead chalcogenide, which had high refractive characteristics. First the theoretical designs of th
Mat. Res.. Publicado em: 11/11/2019
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10. A origem clássica da força do oscilador
Resumo O conceito de força do oscilador é útil em várias áreas da química e da física, tais como emissão e absorção de radiação, constante dielétrica, índice de refração e colisões inelásticas entre partículas carregadas e átomos e moléculas. Na maioria dos livros didáticos, o conceito de força de oscilador é introduzido de forma ad h
Rev. Bras. Ensino Fís.. Publicado em: 07/10/2019
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11. IMPROVEMENT OF AN ANALYTICAL METHOD BASED ON HPLC WITH REFRACTIVE INDEX DETECTION FOR THE ANALYSIS OF GLYCEROL OXIDATION PRODUCTS
The optimized analytical methodology described herein is based on an ion exchange column and an H3PO4 solution (pH 2.24) as the mobile phase, with a flow rate of 0.4 mL min-1 and refractive index detection (RID). On applying the methodology, it was possible to identify 7 products obtained from the oxidation of glycerol with an analysis time of 27 min. The de
Quím. Nova. Publicado em: 26/08/2019
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12. Mineralogical and gemological characterization of emerald crystals from Paraná deposit, NE Brazil: a study of mineral chemistry, absorption and reflectance spectroscopy and thermal analysis
Abstract The Paraná deposit, located at Southwestern Rio Grande do Norte state, in Brazil, is one of the few emerald deposits found at Borborema Province. The mineralization occurs in phlogopite schists and actinolite-phlogopite schists associated with pegmatites and albitites within the Portalegre Shear Zone. Unlike other well-known Brazilian emerald depos
Braz. J. Geol.. Publicado em: 22/08/2019