L Band
Mostrando 13-24 de 864 artigos, teses e dissertações.
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13. Metamaterial-Fractal-Defected Ground Structure Concepts Combining for Highly Miniaturized Triple-Band Antenna Design
Abstract In this paper, a novel method is proposed to increase the gain and radiation efficiency of a compact patch antenna. By employing a combination of three efficient techniques, we have developed a multi-resonance L-DGS antenna with a high gain of 5 dB and an efficiency of 99.6%. Furthermore, a novel compact Double Negative metamaterial unit cell and it
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-12
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14. Carbeto de molibdênio dopado com níquel nanoestruturado para aplicação na degradação de corantes reativos
Resumo Materiais cerâmicos do tipo carbeto, como carbeto de molibdênio dopado com níquel, têm promissora atividade de degradação fotocatalítica. A adição de níquel ao carbeto de molibdênio visa aumentar seu rendimento de reação e também suas características. Este trabalho teve por objetivo estudar a atividade fotocatalítica dos materiais Mo2C
Cerâmica. Publicado em: 2020-12
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15. Caracterização de flogopita para processamento de filtros cerâmicos porosos pelo método da réplica
Resumo Descreve-se a caracterização da matéria-prima flogopita [KMg3(AlSi3O10)(OH)2] e o processo de fabricação de filtros cerâmicos porosos (FCPs) a partir desta, via método da réplica (esponja polimérica) de forma simples e eficaz. A flogopita foi caracterizada por difratometria de raios X (DRX), espectroscopia no infravermelho com transformada de
Cerâmica. Publicado em: 2020-12
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16. Blue-Emitting MWO4:Tm3+ (M: Sr, Ba) Phosphors Prepared by Coprecipitation Method at Room Temperature
MWO4 host matrices (M: Sr, Ba) doped with different Tm3+ concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 mol%) have been successfully prepared by the coprecipitation method at room temperature. The as-prepared nanophosphors were characterized by infrared spectroscopy showing intense absorption bands in the range of 700-1000 cm-1 attributed to the symmetrical
J. Braz. Chem. Soc.. Publicado em: 2020-11
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17. Hypotension and Bradycardia Produced by Transthoracic Application of Low-Intensity Ultrasound Therapy in Hearts of Healthy Rats - A Preclinical Study
Abstract Objective: To investigate the cardiovascular effects produced by transthoracic application of low-intensity pulsed ultrasound therapy (LIPUST). Methods: Three-month-old male Wistar rats (± 300 g, N=16) were randomly allocated in two groups, namely SHAM (control group, faked procedures) and UST (animals treated with LIPUST). These animals, under a
Braz. J. Cardiovasc. Surg.. Publicado em: 2020-10
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18. A Novel Fully Integrated 4-Bit IFM Subsystem Using Band-Stop Filters
Abstract In this paper a 2-4 GHz microstrip IFM (Instantaneous Frequency Measurement) subsystem that uses Wilkinson power dividers, frequency discriminators based on band-stop filters and a DC arduino section is reported. The device uses band-stop filters as an alternative to delay lines, commonly used for IFM. The resonators are responsible for frequency ad
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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19. A Compact, Wideband, Dual Polarized CPW-Fed Asymmetric Slot Antenna for Wireless Systems
Abstract Wideband, dual sense circularly polarized (CP), asymmetric circular slot fed by coplanar waveguide is proposed and designed. Dual polarizations are obtained by using a horizontal stub to the feed line and embedding the L-shaped strip onto the slotted ground plane. The simulated result of impedance bandwidth shows wideband performance is produced by
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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20. STUDY OF SPECTROPHOTOMETRIC CHARACTERISTICS OF THE CHARGE TRANSFER COMPLEX OF TAURINE DRUG WITH 7,7,8,8-TETRACYANOQUINODIMETHANE
A new spectrophotometric method was developed for the determination of taurine using 7,7,8,8-tetracyanoquinodimethane (TCNQ). The method was based on the formation of charge transfer (CT) complex of this drug as n-electron donor with the π-acceptor TCNQ. TCNQ was found to react with taurine to produce a kind of yellow complex. The spectrum obtained for taur
Quím. Nova. Publicado em: 2020-09
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21. Spatial Diversity Effect on the Experimental Gain of Capacity of the Outdoor Mobile Radio Channel in the 700 MHz Band
Abstract From measurements performed in the 700 MHz band, this paper analyzes the effect of spatial diversity on the channel capacity through the propagation of an OFDM mobile radio signal and compares with the results of a single branch providing what improvement of the capacity is attained with the SIMO system.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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22. DEVELOPMENT OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF LEAD BASED ON LOCAL SURFACE PLASMON RESONANCE OF SILVER NANOPARTICLES
Lead is environmental pollutant that even in low trace is harmful for human health and wildlife. In this study we presented a colorimetric method for determination of Pb2+ in water by aggregation of silver nanoparticles capped citrate in the presence of deferoxamine as chelating agent. Silver nanoparticles were prepared by reduction of AgNO3 with NaBH4. In t
Quím. Nova. Publicado em: 2020-06
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23. METHOD DEVELOPMENT AND VALIDATION FOR THE FLUOROQUINOLONES DETERMINATION BY STABILIZED SILVER NANOPARTICLES
Silver nanoparticles (AgNPs) stabilized with glutathione (GSH) were used as nanosensors for the determination of fluoroquinolones such as ciprofloxacin (CIP), norfloxacin (NOR) and enrofloxacin (ENRO) in aqueous systems. The AgNPs were stabilized with GSH (Ag-GSH NPs), whereas the decrease of the surface plasmon resonance (SPR) band at 400 nm and the bathoch
Quím. Nova. Publicado em: 2020-03
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24. Mutual Coupling Reduction in Phased Array Antennas Applying High-Impedance Surface at X Band
Abstract This paper presents a microstrip phased array using High Impedance Surface - Electromagnetic Bandgap (HIS-EBG) in order to minimize the effects of mutual coupling among the antenna elements. Each element of the array is fed by a coaxial cable allowing the beam steering by controlling the signal of the input port of each element. This phased array op
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-03