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简介：In4-strokeinternalcombustionengines,air-fuelratiocontrolisachallengingtaskduetotherapidchangesofenginethrottle,especiallyduringtransientoperation.Toimprovethetransientperformance,managingthecycle-to-cycletransientbehaviorofthemassoftheair,thefuelandtheburntgasisakeyissueduetotheimbalanceofcycliccombustionprocess.Thispaperaddressthemodel-basedestimationandcontrolproblemforcyclicair-fuelratioofspark-ignitionengines.Adiscrete-timemodelofair-fuelratioisproposed,whichrepresentsthecycle-to-cycletransientbehaviorofin-cylinderstatevariablesundertheassumptionsofcyclicmeasurabilityofthetotalin-cylinderchargemass,combustionefficiencyandtheresidualgasfraction.Withthemodel,aKalmanfilter-basedair-fuelratioestimationalgorithmisproposedthatenableustoperformafeedbackcontrolofair-fuelratiowithoutusinglambdasensor.Finally,experimentalvalidationresultisdemonstratedtoshowtheeffectivenessofproposedestimationandcontrolschemethatisconductedonafull-scaledgasolineenginetestbench.

简介：社会的发展,信息技术的进步,要求我们更新教育认识的同时,也为教育新模式的发展和实现提供了契机.以可汗学院为代表的,风靡全球的微型网络教学视频的出现激发了教育研究者对以微视频为载体运用于课堂的教学探索,滋生了一批新的名词,如翻转课堂,慕课,微课,微课程等.[1]在进一步学习可汗学院微课程后,笔者开始反思其与传统教学的反差,希望以其中——比例（Ratio）为例,通过分析比例及比例习题课中微课程的特点、结构,为我们反思教学提供启示.

简介：Theproblemofair-fuelratio(AFR)controloftheportinjectionsparkignition(SI)engineisstillofconsiderableimportancebecauseofstringentdemandsonemissioncontrol.Inthispaper,thestaticAFRcalculationmodelbasedonin-cylinderpressuredataandontheadaptiveAFRcontrolstrategyispresented.Themodelutilisestheintakemanifoldpressure,enginespeed,totalheatrelease,andtherapidburnangle,asinputvariablesfortheAFRcomputation.Thecombustionparameters,totalheatrelease,andrapidburnangle,arecalculatedfromin-cylinderpressuredata.ThisproposedAFRmodelcanbeappliedtothevirtuallambdasensorforthefeedbackcontrolsystem.Inpracticalapplications,simpleadaptivecontrol(SAC)isappliedinconjunctionwiththeAFRmodelforport-injectedfuelcontrol.TheexperimentalresultsshowthattheproposedmodelcanestimatetheAFR,andtheaccuracyoftheestimatedvalueisapplicabletothefeedbackcontrolsystem.Additionally,theadaptivecontrollerwiththeAFRmodelcanbeappliedtoregulatetheAFRoftheportinjectionSIengine.

简介：Ammoniumsulfateresidueisaparticulatesolidandisproducedduringthemanufactureofammoniumsulfatefertilizer.Theresidueusedinthisstudycontainedalargeportionofcalciumcarbonate,fromwhichactivelime（CaO）wasrecoveredviathermaldecomposition.Weusedapurpose-builtdevicetodecomposetheresidueinasemi-suspensionstate.WefoundthatCaOhadthehighestactivitywhenresiduewasdecomposedat850-900℃.OurexperimentsindicatedthatammoniumsulfateresidueshouldbedecomposedinasuspensionstatetoproduceactiveCaO.Basedonourlaboratorytestfindings,anindustrial-scaleproductionlinewithahighsolid/gasratioinasuspensionstatewasdevised.TheoptimaloperatingconditionsforthedecompositionoftheammoniumsulfateresiduetoproducehighqualityCaOwerealsoinvestigated.WefoundthattheCaCO3decompositionratewashighandtheCaOproductwashighlyactive,averaging170sbythecitricacidmethod.MorphologymeasurementsshowedthattheCaOproducthadaporousstructureandalargespecificsurfaceensuringhighactivity.

简介：Forsyngasproduction,thecombustionoffossilfuelsproduceslargeamountsofCO2asagreenhousegasannuallywhichintensifiesglobalwarming.Inthisstudy,chemicalloopingcombustion(CLC)hasbeenutilizedfortheeliminationofCO2emissiontoatmosphereduringsimultaneoussyngasproductionwithdifferentH2/COratioinsteamreformingofmethane(SR)anddryreformingofmethane(DR)inaCLC-SR-DRconfiguration.InCLC-SR-DRwith184reformertubes(similartoanindustrialscalesteamreformerinZagrosPetrochemicalCompany,Assaluyeh,Iran),DRreactionoccursoverRh-basedcatalystsin31tubes.Also,SRreactionishappenedoverNi-basedcatalystsin153tubes.CLCviaemploymentofMn-basedoxygencarrierssuppliesheatforDRandSRreactionsandproducesCO2andH2Oasrawmaterialssimultaneously.AsteadystateheterogeneouscatalyticreactionmodelisappliedtoanalyzetheperformanceandapplicabilityoftheproposedCLC-SR-DRconfiguration.Simulationresultsshowthatcombustionefficiencyreached1attheoutletoffuelreactor(FR).Therefore,pureCO2andH2OcanberecycledtoDRandSRsides,respectively.Also,CH4conversionreached0.2803and0.7275attheoutletofSRandDRsides,respectively.Simulationresultsindicatethat,3223kmolh-1syngaswithaH2/COratioequalto9.826wasproducedinSRsideofCLC-SR-DR.Afterthat,1844kmolh-1syngaswithaH2/COratioequalto0.986wasachievedinDRsideofCLC-SR-DR.ResultsillustratethatbyincreasingthenumberofDRtubesto50tubesandconsidering184fixedtotaltubesinCLC-SR-DR,CH4conversionsinSRandDRsidesdecreased2.69%and3.31%,respectively.However,thissubjectcausedtotalsyngasproductioninSRandDRsides(inallof184tubes)enhanceto5427kmolh-1.Finally,thermalandmolarbehaviorsoftheproposedconfigurationdemonstratethatCLC-SR-DRisapplicableforsimultaneoussyngasproductionwithhighandlowH2/COratiosinanenvironmentalfriendlyprocess.

简介：Thelowfrequencylinecomponentsoftheradiatednoisefromanunderwatertargetusuallyhavebothhighspectrumlevelandsustainedstability.Thisfeaturecouldbeusedtoincreasethedetectionperformanceofconventionalbroadbandenergyintegrationmethod.Therequiredspectrumlevelistheoreticallydiscussedwhenthedetectionperformanceoftheknownlinedetectionisbetterthanthatofbroadbandenergyintegrationmethod.Undertheconditionofthetargetcanbedetectedinlinespectrumband,therelationshipbetweenthelinespectrumlevelandsignaltonoiseratio(SNR)isalsodiscussed.ThispaperproposesalinespectrumtargetdetectionmethodthatamatrixusingDCjumptofluctuationsratiosofsub-bandspatialspectrumandbeamspaceoutputisconstructed.Thismatrixactsasafilterthatthelinespectrumtargetwithcertainfrequencyandazimuthispassedatmost.Byfusingwiththeothersubbandresults,theconventionaldetectionperformancecanbeimproved.Atthesametime,theapplicableconditionanddetectionperformanceareanalyzedinthepaper.Thesimulationandtheseatrialdataprocessingresultsshowthatthealgorithmcaneffectivelyextractweakgoallinespectrumtargetundertheconditionofmulti-interference.Thealgorithmdoesn’tneedmulti-framestatisticsandthedetectionperformanceisclosertotheoptimallinespectrummethod.