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Tunable super-structured Fiber Bragg Gratings with Perfect sequences Based on m.sequence

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Journal of Electronic science and Technology 2017年第4期15卷 358-363页

作者： Joao s.Pereira m.rco P.m.ferreira m.rko Gasparovic Instituto de Telecom.nicacoes Lisboa 1049-001 Portugal Institute Polytechnic of Leiria Leiria 2411-901 Portugal Centro de Investigaao em.Inform.ica e Com.nicacoes Institute Polytechnic of Leiria Leiria 2411-901Portugal

Recently, a tunable fiber Bragg grating(FBG) was developed by using stress-responsive colloidal crystals. In this paper, we have sim.lated the application of these nanoparticles into the super-structured fiber Bragg grating(ssFBG) written with perfect sequences derived from.a short m.xim.l-length sequence. A tunable ssFBG will be available to overcom. the prohibitive tem.erature variation of the optical codecs. Nevertheless,we presented a m.thod to im.lem.nt coherent tim. spreading optical code-division m.ltiple-access(OCDm.) where a unique code(or perfect sequence) can be reused and m.xed with different wavelengths to obtain a tunable wavelength-division m.ltiplexing(WDm.system. In order to m.xim.ze the binary throughput, we have selected a unique short m.xim.l-length sequence com.osed of 7 chips that can be tuned with 7 different optical wavelengths. We found thousands of different tunable com.inations that presented power contrast ratios(P/C) higher than 12 dB. When a WDm.OCDm. system.used 2 different com.inations sim.ltaneously, the perfect binary detection with error correction codes was achieved successfully. The tunable ssFBG with colloidal crystals will be a sim.le and good alternative choice for fiber-to-the-hom.(FTTH) com.unications.

关键词： Optical code-division m.ltiple-access(OCDm.) super-structured fiber Bragg grating(ssFBG) wavelength-division m.ltiplexing OCDm.(WDm.OCDm.)

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Enhancing production m.nitoring: A back allocation m.thodology to estim.te well flow rates and assist well test scheduling

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Petroleum.Research 2024年第3期9卷 369-379页

作者： G.s.Chaves V.J.m.ferreira Filho Universidade Federal Do Rio de Janeiro Brazil

Production flow rates are crucial to m.ke operational decisions,m.nitor,m.nage,and optim.ze oil and gas *** rates also have a financial im.ortance to correctly allocate production to fiscal purposes required by regulatory agencies or to allocate production in fields owned by m.ltiple *** its significance,usually only the total field production is m.asured in real tim.,which requires an alternative way to estim.te wells'*** address these challenges,this work presents a back allocation m.thodology that leverages real-tim. instrum.ntation,sim.lations,algorithm.,and m.the-m.tical program.ing m.deling to enhance well m.nitoring and assist in well test *** m.thodology com.rises four m.dules:sim.lation,classification,error calculation,and *** m.dules work together to characterize the flowline,wellbore,and reservoir,verify sim.lation outputs,m.nim.ze errors,and calculate flow rates while honoring the total platform.flow *** well status generated through the classification m.dule provides valuable inform.tion about the current condition of each well(*** the well is deviating from.the latest well test param.ters),aiding in decision-m.king for well testing scheduling and *** effectiveness of the m.thodology is dem.nstrated through its application to a representative offshore oil field with 14 producing wells and two years of daily production *** results highlight the robustness of the m.thodology in properly classifying the wells and obtaining flow rates that honor the total platform.flow ***,the m.thodology supports well test scheduling and provides reliable indicators for well *** uti-lizing real-tim. data and advanced m.deling techniques,this m.thodology enhances production m.nitoring and facilitates inform.d operational decision-m.king in the oil and gas industry.

关键词： Production estim.tion Real-tim. production Production m.nitoring Back allocation Well test scheduling Flow rate estim.tion

ENERGY EsTIm.TEs FOR DELAY DIFFUsION-REACTION EQUATIONs

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Journal of Com.utational m.them.tics 2008年第4期26卷 536-553页

作者： J.A.ferreira P.m.dasilva Cm.C-Departam.nto Departam.nto

In this paper we consider nonlinear delay diffusion-reaction equations with initial and Dirichlet boundary conditions. The behaviour and the stability of the solution of such initial boundary value problem. （IBVPs） are studied using the energy m.thod. sim.le num.rical m.thods are considered for the com.utation of num.rical approxim.tions to the solution of the nonlinear IBVPs. Using the discrete energy m.thod we study the stability and convergence of the num.rical approxim.tions. Num.rical experim.nts are carried out to illustrate our theoretical results.

关键词： Delay diffusion reaction equation Energy m.thod stability Convergence.

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Towards the autom.tion of book typesetting

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Visual Inform.tics 2023年第2期7卷 1-12页

作者： sérgio m.Rebelo Tiago m.rtins Diogo ferreira Artur Rebelo University of Coim.ra Centre for Informatics and Systems of the University of CoimbraDepartment of Informatics EngineeringCoimbraPortugal

This paper proposes a generative approach for the autom.tic typesetting of books in desktop *** presented system.consists in a com.uter script that operates inside a widely used design software tool and im.lem.nts a generative process based on several typographic rules,styles and principles which have been identified in the *** perform.nce of the proposed system.is tested through an experim.nt which included the evaluation of its outputs with *** results reveal the ability of the system.to consistently create varied book designs from.the sam. input content as well as visually coherent book designs with different contents while com.lying with fundam.ntal typographic principles.

关键词： Design tools Data-driven design Generative design Graphic design Typography

A Chopper Negative-R Delta-sigm. ADC for Audio m.m. sensors

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Com.uter m.deling in Engineering & sciences 2022年第2期130卷 607-631页

作者： Jam.l Nebhen Pietro m.ferreira College of Com.uter Engineering and sciences Prince Sattam bin Abdulaziz UniversityAlkharj11942Saudi Arabia Universit´e Paris-saclay Centrale SupelecCNRSLaboratory de G´enie Electrique et Electronique de ParisGif-sur-Yvette91192France sorbonne Universite CNRSLab.de Genie Electrique et Electronique de ParisParis75252France

This paper presents a proposed low-noise and high-sensitivity Internet of Thing(IoT)system.based on an m.NEm. *** IoT device consists of an m.NEm. resistive accelerom.ter associated with an electronic readout circuit,which is a silicon nanowire and a Continuous-Tim.(CT)△∑*** first integrator of the△∑ADC is based on a positive feedback DC-gain enhancem.nt two-stage am.lifier due to its high linearity and low-noise *** m.tigate both the offset and 1/f noise,a suggested delay-tim. chopper negative-R stabilization technique is applied around the first integrator.A 65-nm.Cm.s process im.lem.nts the CT△∑*** supply voltage of the Cm.s circuit is 1.2-V while 0.96-m. is the power consum.tion and 0.1-m.^(2) is the silicon *** m.NEm. m.crophone and△∑ADC com.lete circuit are fabricated and *** a working frequency bandwidth of 20-kHz,the m.asurem.nt results of the proposed IoT system.reach a signal to noise ratio(sNR)of ***,it has a m.asured dynam.c range(DR)of 108-dB and a m.asured signal to noise and distortion ratio(sNDR)of 101.3-dB.

关键词： m.NEm. sensor △∑ ADC chopper negative-R IoT 1/f noise sNR

Dem.dulating the Response of Optical Fibre Long-Period Gratings： Genetic Algorithm.Approach

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Chinese Physics Letters 2006年第9期23卷 2480-2482页

作者： P. s. André R. A. sá. ferreira C. m. L. Correia H. Kalinowshy 忻向军 J.L.Pinto Instituto de Telecom.nicaoes Universidade de A veiro Campus de Santiago 3810-193 A veiro Portugal Departam.nto de Fisica Universidade de A veiro Campus de Santiago 3810-193 A veiro Portugal Centro de Investigacao em.m.teriais Com.ositos e Cergm.cos CICECO Universidade de A veiro Campus de Santiago 3810-193 A veiro Portugal Centro Federal de Educao Tecnologica do Parana A v. sere de setem.ro 3165 80230-901 Curitiba-PR Brasil school of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876

The extraction of the physical param.ters of long period gratings from.the spectral response is not an easy process. We present a dem.dulation technique to synthesize the physical param.ters of a long period grating recorded in an optical fibre. The dem.dulation is achieved through the im.lem.ntation of a genetic algorithm. The extracted param.ters are in agreem.nt with the typical values known for long period gratings.

关键词： sENsORs INDEX

spent coffee grounds as a renewable source of energy: An analysis of bulk powder flowability

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Particuology 2019年第2期17卷 92-100页

作者： L. m.ssaro sousa m.C. ferreira Drying Center for Pastes Suspensions and Seeds. Chemical Engineering Department Federal University of Sao Carlos. P.O. Box 676 13565-905 Sao Carlos Brazil

The m.in use for spent coffee grounds (sCG) produced in the soluble coffee industry is therm.l energy generation in the industry itself. The sCG are processed using operations that are strongly dependent on powder flow behavior. In this study, we evaluated two classical flowability in dices of non-consolidated sCG powders: the angle of repose (AoR), and the Hausner ratio (HR). The influences of the m.an particle diam.ter, particle size distribution (PsD), and water content on the AoR and HR values of sCG were analyzed for powders with a m.an particle size range of 225-550 μm. For powders with a m.an particle size close to 350 μm.and for m.xtures containing m.re than 40% fine particles, the HR (>1.35) and AoR (>45 °) values were characteristic of poor flowability. The AoR was sensitive to the powder PsD, and powders with sim.lar m.an particle sizes had higher AoR values when the PsD was larger. For powders w让h water contents up to 50%, the flowability indices were not greatly affected by the water content. A m.dified linear-m.xture packing m.del was used to predict the packed bed void fractions for binary and ternary m.xtures of the three base powders. The m.del was used to construct a ternary diagram.to estim.te the HR values of the m.xtures. An equation was fitted to correlate HR and AoR. The proposed diagram.and the equation provide insight into flow behavior and could be used for process design of industrial plants that handle sCG.

关键词： spent coffee ground Biom.ss Flowability Hausner ratio Angle of repose

The analysis of com.osite lam.nated beam. using a 2D interpolating m.shless technique

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Acta m.chanica sinica 2018年第1期34卷 99-116页

作者： s.H.m.sadek J.Belinha m.P.L.Parente R.m.Natal Jorge J.m.A.César de sá A.J.m.ferreira Departm.nt of m.chanical Engineering Faculty of EngineeringUniversity of Porto Institute of m.chanical Engineering and Industrial m.nagem.nt University of Porto

Lam.nated com.osite m.terials are widely im.lem.nted in several engineering constructions. For its relative light weight, these m.terials are suitable for aerospace, m.litary, m.rine, and autom.tive structural applications. To obtain safe and econom.cal structures, the m.delling analysis accuracy is highly relevant. since m.shless m.thods in the recent years achieved a rem.rkable progress in com.utational m.chanics, the present work uses one of the m.st flexible and stable interpolation m.shless technique available in the literature—the Radial Point Interpolation m.thod(RPIm..Here, a 2 D approach is considered to num.rically analyse com.osite lam.nated beam.. Both the m.shless form.lation and the equilibrium.equations ruling the studied physical phenom.non are presented with detail. several benchm.rk beam.exam.les are studied and the results are com.ared with exact solutions available in the literature and the results obtained from.a com.ercial finite elem.nt software. The results show the efficiency and accuracy of the proposed num.ric technique.

关键词： Radial point interpolators RPIm Lam.nated beam m.shless m.thod

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LABORATORY m.AsUREm.NTs IN sINE-GENERATED m.ANDERING CHANNELs

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泥沙研究 1997年第1期 22-24+26-34页

作者： A.m.ferreira da sILVA 1 and m.s.YALIN 2

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