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arXiv 2018年

作者： Mazor, Yarden Alu, Andrea Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical Engineering City College of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10026 United States

Hyperbolic propagation offers exciting opportunities in nanophotonics, from sub-diffraction imaging to enhanced local density of states. This transport regime is typically induced by strong modulation of conductivity, i.e., with alternating metallic and dielectric material properties. Here, we analyze a moving impedance surface, showing that suitably tailored homogeneous metasurfaces can support one-way hyperbolic propagation when in motion, adding non-reciprocity to hyperbolic propagation phenomena, and without suffering from nonlocal effects stemming from discretization or finite granularity of the surface. Copyright © 2018, The Authors. All rights reserved.

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Angular-Momentum Selectivity and Asymmetry in Highly Confined Wave Propagation along Sheath-Helical Metasurface Tubes

arXiv

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arXiv 2018年

作者： Mazor, Yarden Alù, Andrea Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10026 United States Department of Electrical Engineering City College of New York New YorkNY10031 United States

Highly confined surface waves present unique opportunities to enhance light interactions with localized emitters or molecules. Hyperbolic dispersion in metasurfaces allows us to tailor and manipulate surface waves, enhancing the local density of states over broad bandwidths. So far, propagation on this platform was mainly studied in planar geometries, which facilitates the analysis but somehow limits the realm of possibilities. Here we show that "wrapping" hyperbolic metasurfaces into tubes may greatly enrich the wave propagation dynamics along their axis. This system shows strong interaction with fields and sources carrying optical angular momentum, pronounced field asymmetries, and opens pathways to valley-specific excitation and routing. In addition, we demonstrate that various parameter regimes enable strong spin/helicity – momentum locking. Copyright © 2018, The Authors. All rights reserved.

关键词： Surface waves

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Proposal for a Brazilian regulation of electromagnetic compatibility applied to automotive vehicles

Proposal for a Brazilian regulation of electromagnetic compa...

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2016 IEEE International Symposium on Electromagnetic Compatibility, EMC 2016

作者： De São José, Artur N. Resende, Úrsula C. De Menezes, Magno A. Ferreira, José H. Electrical Engineering Post Graduate Program Federal Center for Technological Education of Minas Gerais Belo Horizonte Brazil Electrical Engineering Post Graduate Program Pontifical Catholic University of Minas Gerais Belo Horizonte Brazil

ISBN: (纸本)9781509014415

For the last two decades, electro-electronic components have become more and more integrated into automotive vehicles, with an increasing importance in essential functions implying the safe overall operation of the car. Although these innovations come as a car performance improvement, it can also have adverse effects (some related to safety) in case of malfunction. These undesirable behaviors can be caused by Electromagnetic Interferences (EMI), and the probability increases when a large number of electro-electronic components act together in the same environment, causing failures that may damage part or the whole system. In Brazil, the Electromagnetic Compatibility (EMC) validation of these systems is currently a relative option and the decision of testing or not (and how deep) is up to each car manufacturer. Moreover, most of these validations are still realized out of Brazil, turning developments more expensive, more time-consuming and underusing Brazilian metrology chain. This paper proposes a study of the Brazilian automotive EMC validation context and a comparison with the worldwide scenario, taking into account its technical, economic and social impacts and bringing arguments to discuss a possible federal regulation. This electronic document is a 'live' template and already defines the components of your paper [title, text, heads, etc.] in its style sheet. © 2016 IEEE.

关键词： Electromagnetic compatibility

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A high-order log barrier-based mesh generation and warping method

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Procedia engineering 2017年 203卷 180-192页

作者： Mike Stees Suzanne M. Shontz Department of Electrical Engineering and Computer Science Information and Telecommunication Technology Center The University of Kansas Lawrence KS 66045 USA Department of Electrical Engineering and Computer Science Bioengineering Graduate Program Information and Telecommunication Technology Center The University of Kansas Lawrence KS 66045 USA

The ability to generate high-order meshes that conform to the boundary of curved geometries is a hurdle in the adoption of high-order computational methods for the numerical solution of partial differential equations. In this paper, we propose a method for generating and warping second-order Lagrange triangular and tetrahedral meshes based on a log barrier method. In the case of generation, the approach consists of modifying an initial linear mesh by first, adding nodes at the midpoint of each edge; second, displacing the newly added boundary midpoints to the curved boundary, and third, solving for the final positions of the interior nodes based on the boundary deformation. By allowing all of the boundary nodes to move, the approach can also be used to warp second-order triangular and tetrahedral meshes. We present several numerical examples in both two and three dimensions which demonstrate the capabilities of our method in generating and warping second-order curvilinear meshes.

关键词： high-order mesh generation curvilinear high-order mesh high-order mesh warping numerical optimization

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Optical-electrical probe for two-phase flow investigation

Optical-electrical probe for two-phase flow investigation

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IEEE Sensors

作者： Rosangela Winter Jean Carlos Cardozo da Silva Cicero Martelli Eduardo Nunes dos Santos Marco Jose da Silva Graduate Program in Electrical and Computer Engineering (CPGEI) Federal University of Technology - Parana 3165 Curitiba Parana Brazil 80230-901

ISBN: (纸本)9781509010134

Experimental investigation of two-phase flows is important in many areas of research and industrial application. We introduce a probe based on electrical impedance and Fiber Bragg Grating-based strain measurements, which is able to monitor two-phase flow in pipes. The prototype probe presented consists of an optical fiber with a FBG for sensing encapsulated by a hollow stainless-steel cylinder, which is interrogated for strain and conductance measurements. Raw data is converted to flow parameters such as gas bubble length and velocity. Initial results in a two-phase flow test bench show that the combined optical-electrical technique is feasible and promising to be applied in two-phase flow monitoring.

关键词： flow measurement fiber Bragg grating impedance sensor optical sensor Fiber Bragg gratings TWO PHASE FLOW Flow measurement Probes optical sensors Strain measurement impedance Optical Fibers

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Correction to: Comparison of 12 surrogates to characterize CT radiation risk across a clinical population

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European radiology 2021年第10期31卷 8068页

作者： Francesco Ria Wanyi Fu Jocelyn Hoye W Paul Segars Anuj J Kapadia Ehsan Samei Carl E. Ravin Advanced Imaging Labs Duke University Health System 2424 Erwin Road Suite 302 Durham NC 27710 USA. francesco.ria@duke.edu. Clinical Imaging Physics Group Duke University Health System 2424 Erwin Road Suite 302 Durham NC 27710 USA. francesco.ria@duke.edu. Carl E. Ravin Advanced Imaging Labs Duke University Health System 2424 Erwin Road Suite 302 Durham NC 27710 USA. Clinical Imaging Physics Group Duke University Health System 2424 Erwin Road Suite 302 Durham NC 27710 USA. Medical Physics Graduate Program Departments of Radiology Physics Biomedical Engineering and Electrical and Computer Engineering Duke University 2424 Erwin Road Suite 302 Durham NC 27710 USA.

A Correction to this paper has been published: https://***/10.1007/s00330-021-07903-z

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Nonlocal Metasurfaces for Optical Signal Processing

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Physical Review Letters 2018年第17期121卷 173004-173004页

作者： Hoyeong Kwon Dimitrios Sounas Andrea Cordaro Albert Polman Andrea Alù Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Institute of Physics University of Amsterdam Science Park 904 1098 XH Amsterdam Netherlands Center for Nanophotonics AMOLF Science Park 104 1098 XG Amsterdam Netherlands Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA Department of Electrical Engineering City College of The City University of New York New York New York 10031 USA

Optical analog signal processing has been gaining significant attention as a way to overcome the speed and energy limitations of digital techniques. Metasurfaces offer a promising avenue towards this goal due to their efficient manipulation of optical signals over deeply subwavelength volumes. To date, metasurfaces have been proposed to transform signals in the spatial domain, e.g., for beam steering, focusing, or holography, for which angular-dependent responses, or nonlocality, are unwanted features that must be avoided or mitigated. Here, we show that the metasurface nonlocality can be engineered to enable signal manipulation in the momentum domain over an ultrathin platform. We explore nonlocal metasurfaces performing basic mathematical operations, paving the way towards fast and power-efficient ultrathin devices for edge detection and optical image processing.

关键词： Geometrical & wave optics Imaging & optical processing Metamaterials Nanophotonics Photonics Transformation optics

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Bio-inspired antenna for UWB systems 1

Bio-inspired antenna for UWB systems

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1st International Symposium on Instrumentation Systems, Circuits and Transducers, INSCIT 2016

作者： Da Silva, Paulo Fernandes Freire, Raimundo Carlos Silverio Serres, Alexandre Jean Rene Da Fonseca Silva, Paulo Henrique Costa E Silva, Jefferson Post-Graduate Program in Electrical Engineering -COPELE Federal University of Campina Grande UFCG Campina Grande Brazil Post-Graduate in Electrical Engineering PPGEE Federal Institute of Paraiba João Pessoa Brazil

ISBN: (纸本)9781509033027

In this paper is presented a new printed monopole antenna, bio-inspired by jasmine flower, that meets the Federal Communications Commission parameters for ultra-wideband systems. The design of the printed monopole antenna in jasmine flower has developed from a printed monopole antenna with circular geometry, with comparison results. The measured results of bio-inspired antenna in the jasmine flower showed compatibility with the parameters required by the FCC for ultra-wideband technology. It obtained bandwidth of 9.75 GHz, half-power beamwidth of 148 degrees, omnidirectional radiation pattern, gain of 5.99 dBi, power spectral density below -41.3 dBm across the bandwidth of ultra-wideband technology, small pulse distortion, and constant group delay, with variations of less than 2ns. © 2016 IEEE.

关键词： Bandwidth

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Magnetic-free nonreciprocal photonic platform based on time-modulated graphene capacitors

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Physical Review B 2018年第16期98卷 165428-165428页

作者： D. Correas-Serrano A. Alù J. S. Gomez-Diaz Department of Electrical and Computer Engineering University of California Davis One Shields Avenue Kemper Hall 2039 Davis California 95616 USA Photonics Initiative Advanced Science Research Center City University of New York 85 St. Nicholas Terrace New York City New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA and Department of Electrical Engineering City College of the City University of New York New York New York 10031 USA

We propose a paradigm for the realization of nonreciprocal photonic devices based on time-modulated graphene capacitors coupled to photonic waveguides, without relying on magneto-optic effects. The resulting hybrid graphene-dielectric platform is low loss, silicon compatible, robust against graphene imperfections, scalable from terahertz to near-infrared frequencies, and it exhibits large nonreciprocal responses using realistic biasing schemes. We introduce an analytical framework based on solving the eigenstates of the modulated structure and on spatial coupled mode theory, unveiling the physical mechanisms that enable nonreciprocity and enabling a quick analysis and design of optimal isolator geometries based on synthetic linear and angular momentum bias. Our results, validated through harmonic-balance full-wave simulations, confirm the feasibility of the introduced low-loss (<3 dB) platform to realize large photonic isolation through various mechanisms, such as narrow-band asymmetric band gaps and interband photonic transitions that allow multiple isolation frequencies and large bandwidths. We envision that this technology may pave the wave to magnetic-free, fully integrated, and CMOS–compatible nonreciprocal components with wide applications in photonic networks and thermal management.

关键词： Photonics Plasmonics Graphene Waveguides Lorentz symmetry

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Single-Phase AC-DC-AC Current Source Converter With Reduced DC-Link Oscillation

Single-Phase AC-DC-AC Current Source Converter With Reduced ...

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Applied Power Electronics Conference and Exposition

作者： Louelson A. Costa Montiê A. Vitorino Maurício B. R. Corrêa Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Federal University of Campina Grande (UECG) Campina Grande - PB - Brazil Department of Electrical Engineering Federal University of Campina Grande (UECG) Campina Grande - PB - Brazil

ISBN: (纸本)9781509053674

In this work it is presented an AC-DC-AC synchronization technique that aims to reduce the DC-link current oscillation. The technique is applied to a reduced component count single-phase back-to-back Currente Source Converters (CSC). The deduction of how the DC-link oscillation is influenced by both input and output angles is presented. Experimental and simulation results are provided to validate the theoretical approach and to illustrate the synchronization phenomenon.

关键词： CSC illustrate synchronization phenomenon

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