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简介:ThispaperdiscusseshowtoputintooperationamidrangecomputingclusterfortheNuclearChemistryGroup(NCG)oftheStateUniversityofNewYorkatSTONYBrook(SUNY-SB).TheNCGispartandoneofthecollaboratorswithintheRHIC/PhenixexperimentlocatedattheBrookhavenNationalLaboratory(BNL).ThePhenixdetectorsystemproducesabouthalfaPB(or500TB)ofdataayearandourgoalwastoprovidetothisremotecollaboratingfacilitythemeanstobepartoftheanalysisprocess.Thecomputinginstallationwasputintooperationatthebeginningoftheyear2000.Theclusterconsistsof32peripheralmachinesrunningunderLinuxandcentralserverAlpha4100underDIgitalUnix4.of(formallyTrueUnix64),Inthepapertherealizationprocessisunderdiscussion.
简介:Thispapertreatstheflowinstabilitiesinamixedflowpumpwithavaneddiffuser.Testpumphasapositiveslopeofahead-flowperformancecurveat65%flowrateofBEP(BestEfficiencyPoint)becauseofarotatingstall.DynamicParticleImageVelocimetry(PIV)andpressurefluctuationmeasurementsareusedforinvestigatingthepropagationmechanismofarotatingstall.Itwasfoundthatunstableperformancewascausedbyperiodicallargescaleabruptbackflowgeneratedfromthevaneddiffusertotheoutletofimpeller.Further,therelationbetweenthestaticpressureattheinletofdiffuservaneandtheinternalflowconditionwasclarified.Fromtheseexperimentalresults,inordertoimprovethepositiveslopeofahead-flowperformancecurve,tosuppressthegrowthofstrongvortextowardtheinletofdiffuservanewasprovedtobeakeypoint.
简介:WeinvestigateinthispapertheinfluenceofslowlightonthebalancebetweentheKerrandtwo-photonabsorption(TPA)processesinsiliconslottedhybridnonlinearwaveguides.Threetypicalsiliconphotonicwaveguidegeometriesarestudiedtoestimatetheinfluenceofthelightslow-downfactoronthemodefieldoverlapwiththesiliconregion,aswellasonthecomplexeffectivenonlinearsusceptibility.Itisfoundthatslottedphotoniccrystalmodestendtofocalizeintheirhollowcorewithincreasinggroupindex(n_G)values.Consideringahybridintegrationofnonlinearpolymersinsuchslottedwaveguides,arelativedecreaseoftheTPAprocessbymorefactorof2ispredictedfromn_G=10ton_G=50.Asawhole,thisworkshowsthattherelativeinfluenceofTPAdecreasesforslottedwaveguidesoperatingintheslowlightregime,makingthemasuitableplatformforthird-ordernonlinearoptics.
简介:Inthepresentstudy,weinvestigatedtheeffectofceriumanderbiumdopingofthezirconiumdioxidematrix.Wesynthesizeddopedsamplesusinghydrothermalprocess.Theamountsofdopantusedwere0.5%,1%and5%molar(rareearthoxideoverzirconiumdioxide)respectively.ThesampleshavebeenstudiedviaX-rayDiffractionmeasurementsforthestructuralcharacterization.UVvisiblediffusereflectancewasusedfortheopticalanalysis,Brunauer-Emmett-Teller(BET)modelforthemeasurementofthesurfacearea.Finallythesampleshavebeenanalysedviaelectronparamagneticresonance(EPR)fortheelectroniccharacterization.Thenwetestedthenewsynthetizedmaterialstodeterminetheirphotocatalyticactivityinthereactionofdegradationofmethyleneblueperformedunderirradiationbydiodes(LEDs)emittingexclusivelyvisiblelight.
简介:FERMI,theseededfreeelectronlaser(FEL)inoperationinItaly,isprovidingtheUserCommunitywithuniquefullycoherentradiation,inthewavelengthrange100–4nm.FERMIisthefirstFELfullysynchronizedbymeansofopticalfibers.Theopticaltimingsystemensuresanultra-stablephasereferencetoitsdistributedclients.Severalfemtosecondlongitudinaldiagnosticsverifytheachievedperformance;thebunchlengthmonitor(BLM)andthebuncharrivalmonitor(BAM)willbepresentedinthispaper.Feedbacksystemsplayacrucialroletoguaranteetheneededlongtermelectronbeamstability.Areal-timeinfrastructureallowsshot-to-shotcommunicationbetweenfront-endcomputersandtheservers.Orbitfeedbacksareusefulinmachinetuning,whereaslongitudinalfeedbackscontrolelectronenergy,compressionandarrivaltime.Aflexiblesoftwareframeworkallowsarapidimplementationofheterogeneousmultiinput–multi-output(MIMO)longitudinalloopssimplybyselectingtheappropriatesensorsandactuators.