K Band
Mostrando 1-12 de 1277 artigos, teses e dissertações.
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1. A Compact Dual-Band Self-Diplexing MIMO Patch Antenna for ISM and X-Band Communications
Abstract A compact, dual-band, and self-diplexing MIMO patch antenna with a shared aperture is presented for Industrial scientific medical (ISM) band and X-band communications. The structure consists of two orthogonal feed lines and a rectangular slot in a square patch. The size of the FR4 substrate is 50 × 50 × 1.6 mm3. The designed structure operates at
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Single Port Multimode Reconfigurable UWB-NB Antenna for Cognitive Radio Applications
Abstract In this paper, a compact, single port, multimode reconfigurable UWB-NB antenna with a novel feeding network is presented. The proposed antenna consists of a pentagonal-shaped monopole radiator, a beveled-shaped partial defected ground plane with a rectangular slot, and a reconfigurable bypass feeding network. The antenna realizes a wideband frequenc
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. Synthesis and characterization of α-SnWO4 powders obtained by microwave-assisted hydrothermal method
Abstract The structural, morphological, and optical properties of α-SnWO4 synthesized by microwave-assisted hydrothermal method at 150 °C for different times were investigated. XRD revealed the formation of the orthorhombic phase, without the presence of a secondary phase. The sample processed for 64 min showed a reduction in unit cell volume, suggesting a
Cerâmica. Publicado em: 2022
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4. A Design of a Compact Microwave Diplexer in Microstrip Technology Based on Bandpass Filters Using Stepped Impedance Resonator
Abstract This paper describes the design of a compact microstrip microwave diplexer based on bandpass filters and a stepped impedance resonator for 4G applications. The diplexer is composed of two band-pass filters (BPF) that operate at 1.8 and 2.5 GHz. Both bandpass filters for the receiver at 1.705-1.895 GHZ and the transmitter at 2.41-2.6 GHZ have a -3dB
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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5. X-ray line profile analysis and magnetic and optical properties of FexZn0.95-xCr0.05O nanoparticles fabricated by sol-gel route
Abstract FexZn0.95-xCr0.05O nanoparticles have been obtained for the different concentrations of Fe ions by using the sol-gel method. The hexagonal wurtzite structure of all the samples was confirmed by Rietveld refined X-ray diffraction patterns. The addition of Fe ions decreased lattice constants a and c from 3.2487 to 3.2474 Å and 5.2043 to 5.2029 Å, re
Cerâmica. Publicado em: 2022
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6. Heterogeneous Fenton-like catalytic degradation of phenazine dye over CeO2 (CP-2) nanoscale powder
Abstract A heterogeneous Fenton-like process was explored for oxidation of phenazine dye using ceria polishing material (CP-2). XRD, SEM, FTIR, UV-vis DRS, and pHPZC techniques were applied to characterize the catalyst features. The performance of the heterogeneous Fenton-like process was investigated under various parameters (reaction time, pH, H2O2 concent
Cerâmica. Publicado em: 2022
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7. Effect of Vitiligo on Auditory Functions: Is There Any Association?
Abstract Introduction Vitiligo is an acquired pigmentary disorder of unknown etiology, clinically characterized by whitish macules caused by selective loss of melanocytes. There are many melanocytes in the human cochlea. Recent studies have suggested a direct relation between cochlear dysfunction and decreased amounts of melanin. Objective To determine the
Int. Arch. Otorhinolaryngol.. Publicado em: 2021-04
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8. Low-Overhead Low-Complexity Carrier Phase Recovery Technique for Coherent Multi-Band OFDM-Based Superchannel Systems Enabled by Optical Frequency Combs
Abstract In this paper, we have designed a low-overhead low-complexity carrier phase tracking scheme for OFDM-based superchannel transmission system enabled by optical frequency combs. In this scheme, taking advantage of the broadband phase coherence provided by optical frequency combs among the OFDM-bands, the carrier phase retrieved from pilot-subcarriers
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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9. THEORETICAL INVESTIGATIONS ON DETONATION PERFORMANCE AND STABILITY OF THE DIFLUOROAMINO-PRISMANE DERIVATIVES
The difluoroamino derivatives of prismane were designed and calculated at the B3LYP/6-311G** level. The detonation performances, as well as the band gap, were investigated to look for high energy density compounds. Our calculations showed that difluoroamino group is an effective substitute group for increasing density and heats of formation. All compounds ha
Quím. Nova. Publicado em: 2021-02
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10. 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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11. Classificando cédulas brasileiras (R$) usando análise de imagem por smartphone
A new method to identify the authenticity of Brazilian banknotes (R$) is proposed using digital image analysis by a smartphone application, Photometrix®, associated with chemometric tools. Authentic banknotes (n = 4) obtained in local bank and falsified (n = 12) by the author himself by means of three printers (laser-Deskjet®, wax-Color Qube® and inkjet-D
Quím. Nova. Publicado em: 2020-04
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12. Modular modeling approach for FDM printed structures and piezo disks for metamaterial design
Abstract Research in metamaterials has recently gained interest in the field of noise and vibration control. The ability of creating band gap zones with minimum added mass is the main feature behind its success. In addition, the use of 3D printed parts, particularly the Fused Deposition Modeling (FDM), offers a practical solution for manufacturing parts with
Lat. Am. j. solids struct.. Publicado em: 12/08/2019