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Super modules-based active QR codes for smart trackability and IoT:a responsive-banknotes case study

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npj Flexible Electronics 2020年第1期4卷 93-101页

作者： João F.C.B.Ramalho Sandra F.H.Correia Lianshe Fu Lília M.S.Dias Pedro Adão Paulo Mateus Rute A.S.Ferreira Paulo S.André department of Physics and CICECO-Aveiro Institute of Materials University of Aveiro3810-193 AveiroPortugal department of Computer Science and Engineering and instituto de telecomunicações Instituto Superior TécnicoUniversidade de Lisboa1049-001 LisbonPortugal department of Mathematics and instituto de telecomunicações Instituto Superior TécnicoUniversidade de Lisboa1049-001 LisbonPortugal department of Electrical and Computer Engineering and instituto de telecomunicações Instituto Superior TécnicoUniversidade de Lisboa1049-001 LisbonPortugal

The general use of smartphones assigns additional relevance to QR codes as a privileged tool to the Internet of Things(IoT).Crucial for QR codes is the evolution to IoT-connected smart tags with enhanced storage capacity and secure *** the concept of super-modules(s-modules)built from adjacent spatial multiplexed modules with regular geometrical shapes,assisted by colour multiplexing,we modelled and design a single QR code with,at least,the triple storage capacity of an analogous size black/white QR code,acting as a smart-tag ensuring restrict access and *** s-modules are printed using luminescent low-cost and eco-friendly inks based on organic-inorganic hybrids modified by lanthanides with multiplexed colour emission in the orthogonal RGB *** access to the restrict information is attained only under UV irradiation and encrypted for secure *** concept of active QR codes for smart trackability and IoT was materialised through the development of a free friendly-user mobile app.

关键词： IoT smart modules

OFDM-WDM LR-PON with ultra-bendable fiber for last-mile distribution of quintuple-play service

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Chinese Optics Letters 2013年第8期11卷 18-23页

作者： Tiago M. F. Alves Rakesh Sambaraju Adolfo V. T. Cartaxo Anthony Ng'oma instituto de telecomunicao es Department of Electrical and Computer Engineering Instituto Superior Tcnico Technical University of Lisbon1049-001 Lisbon Portugal Science and Technology department Corning Incorporated One Riverfront PlazaCorning NY 14831 USA

The provision of quintuple-play services along wavelength division multiplexed （WDM） long-reach passive optical networks （LR-PONs） employing an ultra-bendable fiber in last-mile distribution is demonstrated experimentally. Particularly, the simultaneous transmission of three 100-GHz-spaced optical channels for the provision of double sideband orthogonal frequency-division multiplexing （OFDM） wireless and wired quintuple-play services to the premises of users located at 75, 85, and 100 km away from the central office is demonstrated. The OFDM-WDM LR-PON is tested considering the last-mile fiber distribution suffering from severe bending conditions without optical dispersion compensation. The experiments are performed for a worst last-mile fiber bending case emulated by considering a Corning ClearCurve fiber experiencing 20 bends and a bend radius of 7.5 mm. All the OFDM signals received at the premises of users present error vector magnitude （EVM） levels compliant with the EVM thresholds of the corresponding standards. An EVM degradation in the OFDM signals received by each user not exceeding 0.8 dB due to the last-mile distribution fiber is achieved.

关键词： WDM PON OFDM-WDM LR-PON with ultra-bendable fiber for last-mile distribution of quintuple-play service LR

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Gain and ultrafast optical switching in PMMA optical fibers and films doped with luminescent conjugated polymers and oligomers

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Frontiers of Optoelectronics 2010年第1期3卷 45-53页

作者： Ana CHARAS Ana L.MENDON?A Jenny CLARK Juan CABANILLAS-GONZALEZ Luca BAZZANA Alessandro NOCIVELLI Guglielmo LANZANI Jorge MORGADO instituto de telecomunica??es department of Chemical and Biological Engineering Instituto Superior Técnico department of Physics Politecnico di Milano Luceat S.p.A.

Conjugated luminescent polymers and oligomers, exhibiting stimulated emission(SE), are dispersed in polymethylmethacrylate(PMMA), films and optical fibers,either by blending or upon copolymerisation. With this PMMA doping, we aim to achieve gain and ultrafast optical switching. The modification of the dopant's chemical structure allows the tuning of the SE spectral region. Furthermore, we aim to achieve dopant chain isolation while maximising their concentration. In this paper, we present an overview of the research done in this area in the context of the European Union(EU)-funded research project “plastic optical fibers with embedded active polymers for data communications——POLYCOM”.

关键词： plastic optical fibers optical gain and switching conjugated luminescent polymers dopants

Real-time ultra-wideband video streaming in long-reach passive optical networks with wireless radiation in the 10 and 60 GHz bands

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Chinese Optics Letters 2013年第10期11卷 33-38页

作者： Tiago M.F.Alves Maria Morant Adolfo V.T.Cartaxo Roberto Llorente Pierre Cluzeaud Rakesh Sambaraju instituto de telecomunica co es Department of Electrical and Computer EngineeringInstituto Superior T'ecnico Universidade de Lisboa 1049-001 Lisbon Portugal Nanophotonics Technology Centre Universitat Polit`ecnica de Val`encia 46022 Valencia Spain THALes Communications Gennevilliers France Science and Technology department Corning Incorporated One Riverfront Plaza Corning NY 14831 USA

Real-time video streaming using ultra-wideband(UWB) technology is experimentally demonstrated along long-reach passive optical networks(LR-PONs) with different wired and wireless reaches. Experimental tests using external and direct modulation with UWB wireless radiation in the 10- and 60-GHz bands are performed. An ultra-bendable fiber is also considered for a last-mile distribution. The video quality at the output of the optical fiber infrastructure of the LR-PON is assessed using the error vector magnitude(EVM), and the link quality indicator(LQI) is used as a figure of merit after wireless radiation. An EVM below –17 dB is achieved for both externally and directly modulated LR-PONs comprising up to 125 km of optical fiber. EVM improvement is observed for longer LR-PONs when directly modulated lasers(DMLs) are used because of the amplitude gain provided by the combined effect of dispersion and DML's chirp. Compared with optical back-to-back operation, the LQI level degrades to the maximum around 20% for LR-PONs ranging between 75 and 125 km of fiber reach and with a wireless coverage of 2 m in the 10-GHz UWB band. The same level of LQI degradation is observed using the 60-GHz UWB band with a LR-PON integrating 101 km of access network, a last-mile distribution using ultra-bendable fiber, and a 5.2-m wireless link.

关键词： PON LR LQI Real-time ultra-wideband video streaming in long-reach passive optical networks with wireless radiation in the 10 and 60 GHz bands EVM UWB OFDM time

Uniform-velocity spacetime crystals

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Advanced Photonics 2019年第5期1卷 17-42页

作者： Zoé-Lise deck-Léger Nima Chamanara Maksim Skorobogatiy Mário G.Silveirinha Christophe Caloz Polytechnique Montréal Department of Electrical EngineeringMontréalQuebecCanada Polytechnique Montréal Department of Engineering PhysicsMontréalQuebecCanada Universidade de Lisboa-instituto Superior Técnico and instituto de telecomunicações Department of Electrical EngineeringLisbonPortugal

We perform a comprehensive analysis of uniform-velocity bilayer spacetime crystals,combining concepts of conventional photonic crystals and special *** that a spacetime crystal consists of a sequence of spacetime discontinuities,we do this by solving the following sequence of problems:(1)the spacetime interface,(2)the double spacetime interface,or spacetime slab,(3)the unbounded crystal,and(4)the truncated *** these problems,we present the following results:(1)an extension of the Stokes principle to spacetime interfaces,(2)an interference-based analysis of the interference phenomenology,(3)a quick linear approximation of the dispersion diagrams,a description of simultaneous wavenumber and frequency bandgaps,and(4)the explanation of the effects of different types of spacetime crystal truncations and the corresponding scattering *** work may constitute the foundation for a virtually unlimited number of novel canonical spacetime media and metamaterial problems.

关键词： crystals special relativity Lorentz transformations spacetime bandgap structures

Performance Evaluation of Wavelength Division Multiplexing Photonic Analogue-to-Digital Converters for High-Resolution Radar Systems

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Optics and Photonics Journal 2019年第12期9卷 219-234页

作者： Pedro E. D. Cruz Tiago M. F. Alves Adolfo V. T. Cartaxo instituto de telecomunicações Lisboa Portugal instituto Universitário de Lisboa (ISCTE-IUL) Lisboa Portugal

The performance of the wavelength division multiplexing (WDM) photonic analogue-to-digital converter (ADC) used for digitization of high-resolution radar systems is evaluated numerically by using the peak signal-to-noise ratio (SNR) metric. Two different WDM photonic ADC architectures are considered for the digitization of radar signals with 5 GHz of bandwidth (spatial resolution of 3 cm), in order to provide a comprehensive study of the compromises present when deploying radar signals with high-resolution: 1) a four-channel architecture with each channel employing an ADC with 5 GSamples/s, and 2) an eight-channel architecture with each channel employing an ADC with 2.5 GSamples/s. For peak powers of the pulsed source between 10 and 20 dBm and a distance between the radar antenna and the sensing object of 2.4 meters, peak SNR levels between 29 and 39 dB are achieved with the eight-channel architecture, which shows higher peak SNR levels when compared with the four-channel architecture. For the eight-channel architecture and for the same peak powers of the pulsed source, peak SNR levels between 11 and 16 dB are obtained when the distance increases to 13.5 meters. With this evaluation using the peak SNR, it is possible to assess the performance limits when choosing a specific radar range, while keeping the same resolution.

关键词： Analogue-to-Digital Converter Radar Signal-to-Noise Ratio Wavelength Division Multiplexing

A Cell-Based Smoothed Finite Element Method for Modal Analysis of Non-Woven Fabrics

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Computers, Materials & Continua 2021年第6期67卷 2765-2795页

作者： Nguyen T.Quyen N.Dourado A.J.P.Gomes F.B.N.Ferreira C2T—Centro de Ciência e Tecnologia Têxtil Departamento de Engenharia TêxtilUniversidade do MinhoCampus de AzurémGuimarães4804-533Portugal CMEMS-UMinho Departamento de Engenharia MecânicaUniversidade do MinhoCampus de AzurémGuimarães4804-533Portugal department of Computer Science Universidade da Beira InteriorConvento de Sto.AntónioCovilhã6201-001Portugal instituto de telecomunicações R.Marquês deÁvila e BolamaCovilhã6201-001Portugal

The combination of a 4-node quadrilateral mixed interpolation of tensorial components element(MITC4)and the cell-based smoothed finite element method(CSFEM)was formulated and implemented in this work for the analysis of free vibration and unidirectional buckling of shell *** formulation was applied to numerous numerical examples of non-woven *** CSFEM schemes do not require coordinate transformation,spurious modes and numerical instabilities are prevented using bilinear quadrilateral element subdivided into two,three and four smoothing *** improvement of the original CSFEM formulation was made regarding the calculation of outward unit normal vectors,which allowed to remove the integral operator in the strain smoothing *** procedure conducted both to the simplification of the developed formulation and the reduction of computational cost.A wide range of values for the thickness-to-length ratio and edge boundary conditions were *** developed numerical model proved to overcome the shear locking phenomenon with success,revealing both reduced implementation effort and computational cost in comparison to the conventional FEM *** cell-based strain smoothing technique used in this work yields accurate results and generally attains higher convergence rate in energy at low computational cost.

关键词： Mindlin-Reissner theory of plates shear-locking gradient/strain smoothing technique non-woven fabric

Photonics of time-varying media

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Advanced Photonics 2022年第1期4卷 30-61页

作者： Emanuele Galiffi Romain Tirole Shixiong Yin Huanan Li Stefano Vezzoli Paloma A.Huidobro Mário G.Silveirinha Riccardo Sapienza Andrea Alù J.B.Pendry City University of New York Photonics InitiativeAdvanced Science Research CenterNew YorkUnited States Imperial College London Blackett LaboratoryDepartment of PhysicsLondonUnited Kingdom Nankai University School of PhysicsTianjinChina instituto de telecomunicações Instituto Superior Técnico-University of LisbonLisboaPortugal City University of New York Physics ProgramGraduate CenterNew YorkUnited States

Time-varying media have recently emerged as a new paradigm for wave manipulation,due to the synergy between the discovery of highly nonlinear materials,such as epsilon-near-zero materials,and the quest for wave applications,such as magnet-free nonreciprocity,multimode light shaping,and ultrafast *** this review,we provide a comprehensive discussion of the recent progress achieved with photonic metamaterials whose properties stem from their modulation in *** review the basic concepts underpinning temporal switching and its relation with spatial scattering and deploy the resulting insight to review photonic time-crystals and their emergent research avenues,such as topological and non-Hermitian *** then extend our discussion to account for spatiotemporal modulation and its applications to nonreciprocity,synthetic motion,giant anisotropy,amplification,and many other ***,we conclude with a review of the most attractive experimental avenues recently demonstrated and provide a few perspectives on emerging trends for future implementations of time-modulation in photonics.

关键词： time-varying media temporal modulation metamaterials switching optics photonics light

Property mapping of polycrystalline diamond coatings over large area

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Journal of Advanced Ceramics 2014年第1期3卷 56-70页

作者： Awadesh Kumar MALLIK Sandip BYSAKH Monjoy SREEMANY Sudakshina ROY Jiten GHOSH Soumyendu ROY Joana Catarina MENdeS Jose GRACIO Someswar DATTA CSIR-Central Glass&Ceramic Research Institute Kolkata 700032West BengalIndia department of Physics Indian Institute of Technology BombayPowaiMumbai 400076MaharashtraIndia instituto de telecomunicações Campus Universitário de Santiago3810-193Portugal Nanotechnology Research Division Centre for Mechanical Technology and AutomationUniversity of Aveiro3810-193Portugal

Large-area polycrystalline diamond(PCD)coatings are important for fields such as thermal management,optical windows,tribological moving mechanical assemblies,harsh chemical environments,biological sensors,*** plasma chemical vapor deposition(MPCVD)is a standard technique to grow high-quality PCD films over large area due to the absence of contact between the reactive species and the filament or the chamber ***,the existence of temperature gradients during growth may compromise the desired uniformity of the final diamond *** the present work,a thick PCD coating was deposited on a 100-mm silicon substrate inside a 915-MHz reactor;the temperature gradient resulted in a non-uniform diamond *** attempt was made to relate the local temperature variation during deposition and the different properties of the final *** was found that there was large instability inside the system,in terms of substrate temperature(as high asΔT=212℃),that resulted in a large dispersion of the diamond coating’s final properties:residual stress(-15.8 GPa to+6.2 GPa),surface morphology(octahedral pyramids with(111)planes to cubo-octahedrals with(100)flat top surfaces),thickness(190μm to 245μm),columnar growth of diamond(with appearance of variety of nanostructures),nucleation side hardness(17 GPa to 48 GPa),quality(Raman peak FWHM varying from 5.1 cm^(-1) to 12.4 cm^(-1) with occasional splitting).This random variation in properties over large-area PCD coating may hamper reproducible diamond growth for any meaningful technological application.

关键词： plasma-enhanced chemical vapor deposition(CVD) diamond film mechanical properties nanostructures