Angular Stability
Mostrando 1-12 de 54 artigos, teses e dissertações.
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1. 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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2. Double Layer Frequency Selective Surface for Ultra Wide Band Applications with Angular Stability and Polarization Independence
Abstract In this paper, a double layer stopband Frequency Selective Surface (FSS) for Ultra-Wide Band (UWB) applications is presented. The proposed FSS consists of two cascaded conventional FSS, one with double square loops and other with square loops. The − 10dB frequency band from 3.00 GHz to 11.64 GHz is achieved, with a fractional bandwidth of 149 %. E
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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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. Design of Attitude Control Servomechanisms with Fluid Ring and CMG for Rigid Satellite
ABSTRACT: Satellites cover a wide range of space missions as remote sensing. Accomplishment of the mission depends on satellite's stability maintenance and direction. The main task of the attitude control system is to provide stability to the satellite against external disturbances. Such perturbations are caused due to aerodynamic drag, solar radiation and m
J. Aerosp. Technol. Manag.. Publicado em: 08/11/2018
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5. Polarization Insensitive Compact Wide Stop-band Frequency Selective Surface
Abstract A compact, polarization insensitive, wide stop band frequency selective surface is presented. The unit cell is designed by modifying the basic square loop FSS. The simulated value of bandwidth for transmission < ‒ 20 dB for TE incident wave is 7.7 GHz from 4.71 GHz to 12.41 GHz which is 89.95% corresponding to the center frequency of this range. I
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-03
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6. Reducing the Effects of Inaccurate Fault Estimation in Spacecraft Stabilization
ABSTRACT Reference Governor is an important component of Active Fault Tolerant Control. One of the main reasons for using Reference Governor is to adjust/modify the reference trajectories to maintain the stability of the post-fault system, especially when a series of actuator faults occur and the faulty system can not retain the pre-fault performance. Fault
J. Aerosp. Technol. Manag.. Publicado em: 2017-12
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7. Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing
A [211]-oriented niobium single crystal was deformed by equal channel angular pressing (ECAP) at room temperature using the route Bc to a total strain of 9.2. A sharp cube texture develops after ECAP processing. The deformed samples were annealed in vacuum from 400ºC (673 K) to 900ºC (1173 K) for 1 h to evaluate their microstructural stability. Scanning el
Mat. Res.. Publicado em: 13/07/2017
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8. A Novel Simple Convoluted Geometry to Design Frequency Selective Surfaces for Applications at ISM and UNII Bands
Abstract In this paper, we use a novel convoluted geometry to design a dual-band FSS with angular stability and independent polarization operation. The geometry allows the design of a dual-band FSS to block ISM and UNII radio bands. We performed a parametric study with the commercial software ANSYS HFSS. A prototype of our proposed FSS design was built and i
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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9. Comparison of 2 types of treatment of skeletal Class II malocclusions: a 5-year post-retention analysis
Aim: To compare 2 types of treatment for Class II malocclusion assessing mandibular behavior in subjects submitted to full orthodontic treatment with standard edgewise appliance and cervical headgear (Kloehn appliance) and those who used cervical headgear in the first period and with full orthodontic appliance in the second period. Methods: The sample consis
Braz. J. Oral Sci.. Publicado em: 2014-12
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10. Proposal of Fuzzy Control Based on Robust Stability Criteria: An approach in terms of transfer function applied to continuos time dynamic systems with time delay. / PROPOSTA DE CONTROLE BASEADO EM CRITÉRIO DE ESTABILIDADE ROBUSTA: UMA ABORDAGEM EM TERMOS DE FUNÇÃO DE TRANSFERÊNCIA APLICADA A SISTEMAS DINÂMICOS NO TEMPO CONTÍNUO COM ATRASO
Nesta dissertação é proposta uma metodologia de controle PID nebuloso robusto baseado nas especificações das margens de ganho e fase, para sistemas dinâmicos com atraso, no domínio do tempo contínuo. Um modelo nebuloso com estrutura Takagi-Sugeno é utilizado para representar o sistema dinâmico a ser controlado. Assim, a partir dos dados de entrada
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2012
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11. Investigação experimental e analítica do escoamento ao redor de cilindro circular com supressores de VIV. / Experimental and analytical investigation of the flow around circular cylinder with VIV suppressors.
The fluid flow around bluff bodies is one of the main problems in fluid mechanics. The investigations of this phenomenon are based on analytical, numerical and experimental techniques. Each technique presents advantages and disadvantages, being impossible the comprehensive characterization of the flow though only one technique for the majority of body geomet
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/09/2011
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12. Caracterização e aplicação de duas câmaras de extrapolação em feixes padronizados de radiação X / Characterization and application of two extrapolation chambers in standard X radiation beams
The extrapolation chambers are ionization chambers with variable volume, and they are mainly utilized as beta radiation detectors. In this work two extrapolation chambers were characterized, a commercial PTW extrapolation chamber and another extrapolation chamber developed at the Calibration Laboratory of IPEN, for application as reference systems in mammogr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/03/2011