简介:Offshoredrillingandproductionoperationscanresultinspillsorleaksofhydrocarbonsintoseabedsediments,whichcanpotentiallycontaminatethesesedimentswithoil.Ifthisoillatermigratestothewatersurfaceithasthepotentialfornegativeenvironmentalimpacts.Forpropercontingencyplanningandtoavoidlargerconsequencesintheenvironment,itisessentialtounderstandmechanismsandratesforhydrocarbonmigrationfromoilcontainingsedimentstothewatersurfaceaswellashowmuchwillremaintrappedinthesediments.Itisbelievedthattheamountofoiltransportedoutofthesedimentcanbeaffectedbytidalpumping,acommonformofsubterraneangroundwaterdischarge(SGD).However,wecouldfindnostudyexperimentallyinvestigatingthephenomenonoffluidflowinsubseasedimentscontainingoilandtheeffectsoftidalpumping.Thisstudypresentsanexperimentalinvestigationoftidalpumpingtodetermineifitisapossiblemechanismthatmaycontributetotheappearanceofanoilsheenontheoceansurfaceaboveasedimentbedcontainingoil.AnexperimentalapparatuswasconstructedofclearPVCpipeallowingforoilmigrationtobemonitoredasitflowedoutofasandpackcontainingoil,whiletidalpressureoscillationswereappliedinthreedifferentmanners.Theeffectoftidalpumpingwassimulatedviacompressionofairabovethewater(whichsimulatedtheincreasingstaticheadfromtidalexchange).Experimentalresultsshowthatsustainedoilreleaseoccurredfromalltests,andtestswithoscillatingpressureproducedforlongerperiodsoftime.Furthermore,theexperimentalresultsshowedthattheoilmigrationratewasaffectedbygrainsize,oilsaturation,andoscillationwavetype.Inalloscillatingexperimentstherateandultimaterecoverywaslessthanthecomparablestaticexperiments.Fortheconditionsstudied,theexperimentalresultsindicatethatwithanoscillatingpressureontopofasandpack,movementofanon-replenishingsourceofoilissuppressed
简介:TheStokesspectruminthestimulatedRamanscattering(SRS)isverycomplicated.Inthisarticle,weusebothGaussianandLorentzapproximationtoinvestigatethegainpropertiesofmulti-pumpingbroadbandRamanamplifier,andpresentsomeschemesforflatteningthegain.Alltheresultsshowthattheflatnessofthegainspectrumiscloselyrelatedtothepumpingfrequencygrid.ByresearchingthegainpropertiesofRamanamplifiersofsuchITU-TfibersasG.652,G.653,G.655andlargeeffectiveareanon-zerodispersionflatteningfiber,wefindthattheRamangainisassociatedwiththefibertypeanditstransmissioncharacteristics,especiallyitdecreaseswiththeincreaseoftheeffectivecorearea.
简介:Comparedwithendpumpingfibercombiner,oneoftheadvantagesforsidepumpingcombineristheunlimitedpumpingpoints,whichmeansmulti-pointorcascadedsidepumpingcanberealized.However,thelossmechanismofthecascadedstructureisrarelydiscussed.Inthispaper,wepresentthenumericalandexperimentalinvestigationaboutthelossmechanismofatwo-stage-cascadedsidepumpingcombinerbasedontapered-fusedtechnique.Theinfluenceoflossmechanismonthecouplingefficiencyandthermalloadofthefibercoatingisanalyzedaccordingtosimulationsandexperimentswithdifferenttaperingratiosforthefirststage.Basedontheanalysis,acascadedcomponentwithtotalpumpcouplingefficiencyof96.4%handlingapumppowerof1088Wisachievedbyemploying1018nmfiberlaserasthepumpsource.Futureworktofurtherimprovetheperformanceofacascadedsidepumpingcombinerisdiscussedandprospected.
简介:Itispresentedthatthereisapumpingeffectatitsbaseinthedevelopmentprocessofacumulus.Inthestrongeststageofcumulusdevelopment,thepumpingismainlyproducedbythebuoyanceatthebase,andmaybetakenasthefirstapproximationoftheascendingspeedatthebase.Theresultsofnumericalcalculationsandsimulationsoffourobservedradarechoesshowthatasthefirstapproximation,theheightofair-masscumulusmaybesimulatedbyHaltinermodelintheabsenceofob-servedascendingspeedsatthebase,andtheHaltinermodelcanbecharacterizedbythesensitivityofthecumulusdevelopmenttothevirtualtemperatureexcessoverenvironmentatthebase.
简介:A2-DLatticeBoltzmannMethod(LBM)coupledwithaSub-GridStress(SGS)modelisproposedandvalidatedbyflowsaroundanon-submergedspurdikeinachannel.AndthentheLBM-SGSmodelisfurtherappliedtoflowsinapumping-stationforebay.ShallowwaterequationsarenumericallysolvedbytheLBMandtheturbulencecanbetakenintoaccountandmodeledefficientlybytheLargeEddySimulation(LES)model.Thebounce-backschemeofthenon-equilibriumpartofthedistributionfunctionisusedattheinletboundary,thenormalgradientofthedistributionfunctionissetaszeroattheoutletboundaryandthebounce-backschemeisappliedtothesolidwalltoensurenon-slipboundaryconditions.Firstly,themodelsuccessfullypredictstheflowcharacteristicsaroundaspurdike,suchascirculatingflow,velocityandwaterdepthdistributions.TheresultsareverifiedbytheexperimentaldataandcomparedtotheresultsobtainedbyconventionalSmagoringskyModel(SM)ofLES.Finally,theLBM-SGSmodelisusedtofurtherpredicttheflowcharacteristicsinaforebay,suchassecondaryflowandwaterlevel.Thecomparisonsshowthatthemodelschemehasthecapacitytosimulatecomplexflowsinshallowwaterwithreasonableaccuracyandreliability.
简介:ThewaveCoriolis-Stokes-Force-modifiedoceanmomentumequationsarereviewedinthispaperandthewaveStokestransportispointedouttobepartoftheoceancirculations.UsingtheEuropeanCentreforMedium-RangeWeatherForecasts40-yearreanalysisdata(ERA-40data)andtheSimpleOceanDataAssimilation(SODA)version2.2.4data,themagnitudeofthistransportiscomparedwiththatofwind-drivenSverdruptransportanda5-to-10-precentcontributionbythewaveStokestransportisfound.Bothtransportsarestrongerinborealwinterthaninsummers.Thewaveeffectcanbeeithercontributionorcancellationindifferentseasons.ExaminationwithKuroshiotransportverifiessimilarseasonalvariations.Theclarificationoftheefficientwaveboundaryconditionhelpstounderstandtheroleofwavesinmasstransport.Itactsassurfacewindstressandcanbefunctionaldowntothebottomoftheageostrophiclayer.Thepumpingvelocitiesresultingfromwave-inducedstressarezonallydistributedandaresignificantinrelativelyhighlatitudes.Furtherworkwillfocusonthemodelperformanceofthewave-stress-changed-boundaryandtheroleofswellsintheeasternpartoftheoceans.
简介:BackgroundThrombocytopeniaisacommoncomplicationofIABP.Untilnow,thereisnounifiedconclusionsabouttheincidence,characteristics,riskfactorsandtheprognosisofIABPrelatedthrombocytopenia.MethodsInthisstudy,thedataofpatientswithACSundergoingPCIandIABPwereretrospectivelyanalyzed.Allenrolledpatientsweredividedintothrombocytopeniagroupandnon-thrombocytopeniagroupaccordingtotheoccurrenceofthrombocytopeniaafterinsertionofIABP.Thebaselinedataofthetwogroupswerecompared,andthepossibleriskfactorsofthrombocytopeniaandtheirimpactonprognosiswereanalyzedbychi-squaretestandlogisticregressionanalysis.ResultsSixty-twopatientswereenrolledinthisstudy.TherateofIABPassociatedthrombocytopeniawas25.8%(16/62)ofallpatients.OlderagewasanindependentriskfactorofIABPassociatedthrombocytopenia(OR:3.625;95%confidenceinterval:1.016-12.935;P=0.047).TheincidenceofTIMIbleedingeventswashigherinthrombocytopeniagroup[75.0%(12/16)vs.43.5%(20/46),P=0.042].Therateofin-hospitaldeathwassimilarbetweenthetwogroups[18.8%(3/16)vs.17.4%(8/46),P=1.0].ConclusionIABPassociatedthrombocytopeniaoccursin25.8%ofpatientswithACSundergoingPCIandcorrelateswithincreasedTIMIbleedingevents.OlderagemaypredictIABPassociatedthrombocytopenia.
简介:RelativerolesofEkmantransportandEkmanpumpingindrivingsummerupwellingintheSouthChinaSea(SCS)areexaminedusingQuikSCATscatterometerwinddata.ThemajorupwellingregionsintheSCSarethecoastalregionseastandsoutheastofVietnam(UESEV),eastandsoutheastofHainanIsland(UESEH),andsoutheastofGuangdongprovince(USEG).ItisshownthattheEkmantransportduetoalongshorewindsandEkmanpumpingduetooffshorewindstresscurlplaydifferentrolesinthethreeupwellingsystems.InUESEV,EkmanpumpingandEkmantransportareequallyimportantingeneratingupwelling.TheEkmantransportincreaseslinearlyfrom0.49SvinMayto1.23SvinAugust,whiletheEkmanpumpingincreasesfrom0.36to1.22Svduringthesameperiod.InUESEH,themeanestimatesofEkmantransportandEkmanpumpingare0.14and0.07Sv,respectively,indicatingthat33%ofthetotalwind-drivenupwellingisduetoEkmanpumping.InUSEG,themeanEkmantransportis0.041SvwiththepeakoccurringinJuly,whileEkmanpumpingismuchsmaller(0.003onaverage),indicatingthattheupwellinginthisareaisprimarilydrivenbyEkmantransport.Inthesummersof2003and2007followingElNio-SouthernOscillation(ENSO)events,bothEkmantransportandEkmanpumpingdecreaseinUESEVduetotheabnormallyweaksouthwestmonsoon.Duringthesameevents,however,EkmantransportisslightlyenhancedandEkmanpumpingisweakenedinUESEHandUSEG.
简介:backgroundToinvestigatetheeffectofintra-aorticballoonpumping(IABP)onno-reflowphenomenoninprimarypercutaneouscoronaryintervention(PCI)forST-ElevationMyocardialInfarction(STEMI).MethodsClinicaldataof22acutemyocardialinfarctionpatientsafterPCIwithangiographicno-reflowphenomenonwereretrospectivelyanalyzedbetweenJanuary2006andDecember2009.12patientsunderwentIABP,other10patientsascontrolgroup.Weobserveddifferenceofcardiacstructure,brainnatriureticpeptide(BNP)andventricularsystolicfunctionbetweentwogroup,aswellascardiacinjurymarkers(MYO,CK-MB,cTnI)inbothgroupsonthedaysof1,2,3,5,7,10afterthedifferentinterventions.Inaddition,cardiacstructureandventricularsystolicfunctionincludingleftatriummedialdiameter(LAMD),leftventricularmedialdiameter(LVMD),leftventricularejectionfraction(LVEF)wasevaluatedafter10days,3months,6months.Finally,statisticswasusedtoanalysisthedata.ResultsTheseveralvasoactivesubstancesaswellascardiacinjurymarkersandLAMD,LVMD,LVEFof10days,3months,6monthsofIABPgroupweresignificantdifferencewithcontrolgroup(P<0.05).BNPtargetsofIABPgroupcomparedwiththecontrolgroupnosignificantdifference(P>0.05).ConclusionsIABPhaseffectsonprognosisinSTEMIpatientswhoperformedPCIwithangiographicno-reflowphenomenon,whichisconducivetorecoveryofheartfunction.
简介:Steelproductionremainsanenergy-intensiveindustryinaworldwherethereisanever-increasingemphasisonloweringenergycosts,reducinggreenhousegasemissions,ensuringenvironmentalcompliance,andimprovingproductionrates.Asthegrowthindemandforspecialitysteelscontinuesitssteadyincrease,andnewmarketopportunitiesforeverhighersteelperformanceappear,significantglobalattentionisfocusedonsecondarysteelprocessing,andontheVD,VODandRHprocesses.Onenewtechnologyisabletoaddressalloftheseissuesandconcernstogether-theintegratedladletankvacuumdegassingstationequippedwiththenewmodularmechanicalvacuumpumpingsystems.Thispaperwillexaminetheeconomicandenvironmentalbenefits,operationalcharacteristics,andrecentresultsprovidedbysuchsteeldegassinginstallations.
简介:Anall-fiberizedandnarrow-bandwidthmasteroscillatorpoweramplification(MOPA)systemwithrecordoutputpowerof4kWlevelandslopeefficiencyof78%isdemonstrated.Tandempumpingstrategyistentativelyintroducedintothenarrow-bandwidthMOPAsystemforthermallyinducedmodeinstability(TMI)suppression.ThestimulatedBrillouinscattering(SBS)effectisbalancedbysimplyusingone-stagephasemodulationtechnique.Withdifferentphasemodulationsignals,SBSlimitedoutputpowersof336W,1.2kWand3.94kWarerespectivelyachievedwithspectralbandwidthsaccountingfor90%powerof~0.025,0.17and~0.89nm.Comparedwithourprevious976nmpumpingsystem,TMIthresholdisoverallboostedtobe>5timesinwhichtandempumpingincreasestheTMIthresholdof>3times.Thebeamquality(M~2factor)oftheoutputlaseriswellwithin1.5belowtheTMIthresholdwhileitisultimatelysaturatedtobe1.86withtheinfluenceofTMIatmaximaloutputpower.ExceptforSBSandTMI,stimulatedRamanscattering(SRS)effectwillbeanotherchallengeforfurtherpowerscaling.InsuchahighpowerMOPAsystem,multidetrimentaleffects(SBS,SRSandTMI)willcoexistandmaybemutual-coupled,whichcouldprovideawellplatformforfurthercomprehensivelyinvestigatingandoptimizingthehighpower,narrow-bandwidthfiberamplifiers.
简介:TheaveragepoweroffiberlasershasbeenscaleddeeplyintothekWregimeinthepastyears.However,stimulatedRamanscattering(SRS)isstillamajorfactorlimitingfurtherpowerscaling.Here,wehavedemonstratedforthefirsttime,tothebestofourknowledge,thesuppressionofSRSinahalf10kWtandempumpingfiberamplifierusingchirpedandtiltedfiberBragggratings(CTFBGs).Withspeciallyself-designedandmanufacturedCTFBGsinsertedbetweentheseedlaserandtheamplifierstage,amaximumSRSsuppressionratioof>15dBinspectrumisobservedwithnoreductioninlaserefficiency.WithoneCTFBG,theeffectiveoutputpowerisimprovedto3.9kWwithabeamqualityM2factorof~1.7from<3.5kWwithanM2factorof>2;withtwoCTFBGs,theeffectivelaserpowerreaches4.2kWwithanincreasingratioof20%andanM2factorof~1.8,andfurtherpowerimprovementislimitedbythepowerandperformanceofthe1018nmpumpsources.ThisworkprovidesaneffectiveSRSsuppressionmethodforhigh-powerall-fiberlasers,whichisusefulforfurtherpowerscalingofthesesystems.
简介:40-GHzclockmodulatedsignalasapumptoimprovetheefficiencyoffour-wavemixing(FWM)-basedwavelengthconversionina26.5-kmdispersionshiftedfiber(DSF)isinvestigated.TheexperimentalresultsdemonstratethattheconjugatedFWMcomponenthashigherintensitywiththeclockpumpingthanthatwiththecontinuous-wave(CW)lightpumping.TheimprovementofFWM-basedwavelengthconversionefficiencyisnegligiblewhenthepumppowerislessthanBrillouinthreshold.ButwhenthepumppowerisgreaterthanBrillouinthreshold,theimprovementbecomessignificantandincreaseswiththeincrementofpumppower.Theimprovementcanincreaseupto9dBifpumppowerreaches17dBm.