Space Structure
Mostrando 1-12 de 1115 artigos, teses e dissertações.
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1. Microstrip 3-Bit Fractal-based Phase Shifter
Abstract This paper presents the implementation of a 3-bit microstrip fractal-based phase shifter operating in the 430 MHz to 470 MHz frequency range. The fractal structure is used to confine different delay line lengths in the same area due to the space-filling properties of the used Hilbert fractal curve. The proposed design has three bits corresponding to
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. A New Miniaturized Low-Profile and Stable Dual-Band FSS with 2.5D Structure for ISM Bands
Abstract Based on 2.5-Dimensional (2.5D) frequency selective surface (FSS) structures, a new miniaturized frequency selective surface structure is proposed in this work to operate as a bandreject filter in the 2.4 GHz (2400 to 2483.5 MHz) and 5 GHz (5150 to 5350 MHz and 5470 to 5725 MHz) ISM (Industrial, Scientific, and Medical) bands. The FSS has the metall
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. Doxazosin adsorption in natural, expanded, and organophilized vermiculite-rich clays
Abstract Vermiculite clays are adsorbent materials that have good chemical adsorption capacity, which makes them applicable in the removal of drugs from aqueous solutions. Their lamellar structure can be easily expanded and organophilized. To assess the efficacy and environmentally-tolerant capacity of the adsorption method, the organophilized vermiculite cl
Cerâmica. Publicado em: 2022
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4. Synthesis and Molecular Modeling Study of Two Bromo-Dimethoxybenzaldehydes
This work describes the synthesis, molecular structure, and packaging of the compounds 6-bromo-2,3-dimethoxybenzaldehyde (6-BRB) and 5-bromo-2,3-dimethoxybenzaldehyde (5 BRB). Characterization in the solid-state was carried out by X-ray diffraction, and the analysis of the interactions was described by the Hirshfeld surface, which helps in understanding the
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. First-Principles Calculations of a New Semi-Conductive Carbon Allotrope Named ABF-Carbon
Carbon is an extremely versatile element and can generate a plethora of structures with distinct properties. Proposing new possible metastable allotropic structures for carbon has been the subject of increasing interest over the past few years. In this contribution, we present a new carbon allotrope, named ABF-Carbon, based on the connection of spiropentadie
J. Braz. Chem. Soc.. Publicado em: 2021-04
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6. Automated Framework for Developing Predictive Machine Learning Models for Data-Driven Drug Discovery
The increasing availability of extensive collections of chemical compounds associated with experimental data provides an opportunity to build predictive quantitative structure-activity relationship (QSAR) models using machine learning (ML) algorithms. These models can promote data-driven decisions and have the potential to speed up the drug discovery process
J. Braz. Chem. Soc.. Publicado em: 2021-01
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7. Optimization of geometrically nonlinear truss structures under dynamic loading
Abstract The goal of this article is to present the formulation of the optimization problem of truss structures with geometric nonlinearity under dynamic loads and provide examples of this problem. The formulated optimization problem aims to determine the cross-sectional area of the bars that minimizes the weight of the structure, imposing constraints on nod
REM, Int. Eng. J.. Publicado em: 2020-09
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8. Crystallographic Changes Accompanying the Verwey Transition in a Magnetite from Steatite
The crystallographic structural analysis of the magnetite of a steatite rock at 298 K, (saturation magnetization, σ = 95.0 J T-1 kg-1) showed two cubic networks and, below Verwey temperature (TV ca.120 K) a monoclinic structure, basing on their cell dimensions and different transitional behaviors when reducing the temperature. A monoclinic structure was ide
J. Braz. Chem. Soc.. Publicado em: 2020-09
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9. Evaluation of the Influence of the Substituting Cation on the Structural and Morphological Properties of the New Garnet Sm3−xREExFe5O12 (REE = Dy, Gd and Lu)
Rare earth garnets (REE3Fe5O12) have magnetic-electric and optical properties that can be used in transmitters, microwave and data storage devices. These properties depend mainly on partial or total substitution of the cationic sites, as well as by the synthesis method used. Therefore, in this work was studied the influence of the substituting cation on the
Mat. Res.. Publicado em: 20/01/2020
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10. Development and validity evidence of the multidimensional scale of sexual selfconcept in a Spanish-speaking context
Abstract Background/objective: STIs and HIV/AIDS are an important public health problem, transmitted by risky sex behaviours. In this context, it is necessary to identify protective factors, of those behaviours, as sexual self-concept. Sexual self-concept is a multidimensional trait (i.e. sexual self-esteem; sexual self-efficacy; and sexual assertiveness),
Psicol. Reflex. Crit.. Publicado em: 13/01/2020
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11. Ultrasound-guided costoclavicular block as an alternative for upper limb anesthesia in obese patients
Resumo Justificativa e objetivos: O bloqueio de plexo braquial via costoclavicular é uma anestesia feita por via infraclavicular, já descrita na literatura como uma via segura e efetiva para anestesia de membro superior distal ao cotovelo. O relato a seguir trata de um paciente em que as técnicas tradicionais para bloqueio de plexo apresentavam dificulda
Rev. Bras. Anestesiol.. Publicado em: 20/12/2019
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12. EXTENSÃO COMO FERRAMENTA DE APROXIMAÇÃO DA UNIVERSIDADE COM O ENSINO MÉDIO
Resumo Este trabalho relata uma experiência de extensão universitária que teve como objetivo integrar e divulgar os cursos de saúde da Universidade Estadual de Roraima (UERR), com foco em estudantes que estão concluindo o ensino médio ou cursando cursinhos pré-vestibulares. Os estudantes convidados têm a oportunidade de conhecer mais sobre os cursos
Cad. Pesqui.. Publicado em: 09/12/2019