Characterlife
HeikeKamelinOnnes’fatherownsatilefactory,butheHismother'sartisticliteracywasquitegood,whichdeeplyinfluencedhim.Hisbrother-in-lawwasafamouspainterinLeidenatthetime.
BorninGroningenonSeptember21,1853.Healsodabbledinpoetrywhenhewasyoung.
In1870,heenteredtheUniversityofGroningentostudyphysics,andthentransferredtotheUniversityofHeidelberginGermanythefollowingyear,wherehehadtheopportunitytoconsultthechemistRobertWilhelmBunsenandthephysicistKirchhoff..
ReturnedtoGroningenin1873.Receivedadoctoratein1879.
In1882,heservedasprofessorofexperimentalphysicsatLeidenUniversityandfoundedtheworld-famouscryogenicresearchcenter-LeidenLaboratory.
In1911,Onnisusedliquidheliumtocoolgoldandplatinumbelow4.3Kandfoundthattheresistanceofplatinumwasaconstant.Thenhecooledthemercurytobelow4.2Kandmeasuredthatitsresistancedroppedtoalmostzero.Thisisthesuperconductivityoftheobject.
In1913,Onnisdiscoveredthattinandleadareassuperconductingasmercury.
In1913,OnniswasawardedtheNobelPrizeinPhysicsforhisresearchonthepropertiesofmatteratlowtemperaturesandliquefiedhelium.UndertheleadershipofOnnis,thePhysicsLaboratoryofLeidenUniversitybecametheresearchcenteroflow-temperaturephysicsintheworld.
In1923,OnnisretiredanddiedinLeidenonFebruary21,1926.
Scientificresearch
Attheendofthe19thcenturyandthebeginningofthe20thcentury,therewasaworldwidecompetitionintheexperimentalresearchoflowtemperature.Inthissensationalsciencecompetition,theleaderisthecryogeniclaboratoryinLeiden,asmallcountryinNorthwesternEurope.
Inthesecondhalfofthe19thcentury,Dutchphysicistsmadeimportantcontributionstothestudyoftherelationshipbetweengaspropertiesandchangesinpressureandtemperature.In1873,inhisdoctoraldissertation"TheContinuityofGasandLiquid",VanderWaalsproposedthe"EquationofState"includinggasandliquid,namelytheVanderWaalsequation.In1880,VanderWaalsputforwardthe"LawofCorrespondenceState",furtherobtainingthegeneralformoftheequationofstate.Underhistheoreticalguidance,theBritishJ.Dewarrealizedtheliquefactionofhydrogenin1898.TheUniversityofLeidenwhereheworkshasdevelopedcryogenicexperimenttechnologyandestablishedacryogeniclaboratory.Thefounderofthislaboratoryisthefamouslow-temperaturephysicistKamerlinOnnes.
SinceFarafirstobservedliquefiedchlorinein1823,theliquefactionofvariousgasesandtherealizationoflowertemperatureshavealwaysbeenimportantsubjectsofexperimentalphysics.However,thescaleoftheexperimenthasneverbeenabletomeettheneeds.
In1877,L.P.CaillettetandP.P.PictetrealizedtheliquefactionofoxygensimultaneouslyinFranceandSwitzerland.In1895,GermanC.V.LindeandBritishW.HampsonusedtheJoule-Thomsoneffect(thethrottlingexpansioneffect)tostartlarge-scaleproductionofliquidoxygenandliquidnitrogen.ThefamousLindemachinebecamethebasicequipmentofcryogenictechnology.Afewyearslater,theDewaroftheRoyalInstituteofEnglandachievedtheliquefactionandsolidificationofhydrogen.Hethoughthehadreachedthelimitoflowtemperature,butthenfoundthatheliumwasstillintheresidualgas.However,afteryearsofhardwork,manymethodshavenotbeenusedtoachievetheliquefactionofhelium.KamerlinOnnesisdeterminedtoconquerthiscryogenicfortress,hepayscloseattentiontotheconstructionofcryogenicequipment.
Atthattime,thelowtemperaturewasmainlyobtainedbyliquidevaporationandgasthrottlingexpansion.Togetaverylowtemperature,itisoftennecessarytoadoptacascademethod,thatis,firstcompressthegastobeliquefied,andatthesametimeusetheevaporationofanotherliquidtotakeawaytheheat,andthenallowthegastothrottleandexpand,andthegasconsumesexternalwork.Abletocooldown.Thisprinciplehasbeensolvedphysicallyandthereisnothingnew,buttherearemanytechnicalproblemsinpractice.Designersmustconsidervariousphysicalproblemsandthetechnicalequipmentneededtosolvetheseproblems.Manyinstrumentsneedtobemanufacturedbythemselves,andevenelectricityneedstobeprovidedbythemselvesatthebeginning.KamerlinOnnesimprovedthelaboratoryequipmentwithgreatenergy,makingitdevelopfromaninitialscaletoalatecomer.Buthepaysmoreattentiontotalenttraining.Hefoundedatechnicalschool,allowingstudentstostudyatnightandworkinthelaboratoryduringtheday.Theglasstechnicianshetrainednotonlymettheneedsofhiscountry,butwerealsohiredtoworkinphysicslaboratoriesinmanycountriesandcontributedtothedevelopmentofcryogenicphysicsandvacuumtechnology.HecultivatedtalentsforindustryandhadacertaininfluenceonthedevelopmentofindustryintheNetherlands.KamerlinOnnesalsorecruitedscienceandtechnologypersonnel,includingvisitingscholarsfromabroad,togatheraroundhim.Underhisorganizationandleadership,theLeidenCryogenicLaboratoryestablishedin1894afactorycapableofmassproductionofliquidhydrogenandothergases(includinghelium)andalarge-scalelaboratorybuilding.Hesetupalaboratoryonanindustrialscaleforthefirsttimeinhistory.Itstartsfromhere.Physicshasmovedfromahandicraftapproachtoamodernlarge-scalelevel.
July10,1908isadayofhistoricalsignificance.Onthisday,aftercarefulpreparation,KamerlinOnnesandhiscolleaguesworkedcollectivelyonkeyproblemsandfinallyliquefiedhelium.Itmarkedthefirststageof"bigscience"inthe20thcentury,andthefirstvictorywasachieved.Inordertodothisexperiment,Kamerlin-Onness'spreparationswereextremelymeticulous.Hemadeatheoreticalestimateoftheliquefactiontemperatureofheliuminadvance,whichisexpectedtobe5Kto6K.Thereisalargereserveofhelium,andthereisanadequatesupply.Liquidhydrogenishomemade.Onedaybeforetheexperiment,75Lofliquidairwaspreparedforstandby.At5o'clockinthemorning,20Lofliquidhydrogenwasreadyandgraduallypouredintotheheliumliquefier.Pre-coolingwithliquidhydrogenmustbeextremelycareful,ifaverysmallamountofairismixedintothesystem,allpreviouseffortswillbelost.Athalfpastoneintheafternoon,allheliumwaspouredintotheheliumliquefierandtheheliumgaswascirculated.Thethermostatinthecenteroftheliquefierbegantoenteralowtemperaturethathasneverbeenreached,andthistemperaturecanonlybeindicatedbyaheliumthermometer.However,nochangeintheindicatorcanbeseenforalongtime.Peopleadjustthepressure,changetheexpansionpiston,andusevariouspossiblemeasurestopromotetheoperationoftheliquefier.Thethermometersseemtobemovinganditisdifficulttomakejudgments.Atthistime,theliquidhydrogenwasnearlyexhausted,andtherewasstillnosignofliquidhelium.At7:30intheevening,seeingthattheexperimentwasabouttoendinfailure,aprofessorwhocametowatchthenewssuggestedtoKamerlinOnneswhethertheheliumgasoftheheliumthermometeritselfwasalsoliquefied,coulditbedonefromIlluminatethecontainerbelowandseehowitis?Onnestonopenedthemossandimmediatelyfollowedsuit.Asaresult,hewasoverjoyed.Itturnedoutthatthecentralthermostatwasalmostfilledwithliquid,andthereflectionoflightmadepeopleseetheliquidsurface.Thistime,KamerlinOnnesobtainedatotalof60cmofliquidhelium,reachingalowtemperatureof4.3K.Aftermanyexperiments,theyreached1.38K～1.04Kinthesecondyear.
However,KamerinOnnes’sgoalisnotonlytoobtainalowertemperature,toachievetheliquefactionandsolidificationofgas,butalsotoexplorethevariouspropertiesofsubstancesunderextremelylowtemperatureconditions.Theresistanceofmetalsisoneofhisresearchobjects.Atthattime,thereweredifferentopinionsandspeculationsaboutthechangeofmetalresistancewhenitwasclosetoabsolutezero.Accordingtotheclassicaltheory,theresistanceofpuremetalsshouldgraduallydecreaseasthetemperaturedecreases,reachingzeroatabsolutezero.Somepeoplethinkthatthistheoryisnotnecessarilyapplicabletoextremelylowtemperatures.Whenthetemperaturedecreases,theresistanceofthemetalmayfirstreachaminimumvalueandthenincreaseagain,becausefreeelectronsmaycondenseonatoms.Accordingtothisview,theresistanceofmetalsatabsolutezeromayincreaseindefinitely.Thepredictionsofthetwoviewsarediametricallyopposite.Onlyexperimentscanmakeajudgment.
KamalinOnnesfirstusedplatinumwireasatestsample,andmeasuredresistancebyaWheatstonebridge.Themeasuredplatinumresistancefirstdecreasedwiththetemperature,butwhenitfellbelowtheliquidheliumtemperature(4.3K),theresistancechangedsmoothly.SoKamerlinOnnesandhisstudentClay(Clay)publishedapaperin1908todiscussthisphenomenon.Theybelievethatimpuritieshaveaneffectonplatinumresistance,whichmakesplatinumresistanceindependentoftemperature;ifthemetalissopurethattherearenoimpurities,itsresistanceshouldslowlyapproachzero.
Inordertotestwhetherhisjudgmentiscorrect,KamerlinOnneshopesthatmercuryispurerthanplatinumandgold.Mercurywasthemetalwiththehighestpurityatthetime,andcontinuousdistillationwasusedtodothis.OnedayinApril1911,KamerlinOnnesaskedhisassistantG.Holsttoconductthisexperiment.Themercurysampleisimmersedinaheliumthermostat,andaconstantcurrentflowsthroughthesample.Measurethepotentialdifferencebetweenthetwoendsofthesample.Unexpectedly,whenthetemperaturedroppedbelowtheboilingpointofhelium(4.2K),thepotentialdifferencesuddenlydroppedtozero.Couldtherebeashortcircuitintheline?Intheprocessoffindingthecauseoftheshortcircuit,Holstfoundthatwhenthetemperatureroseabove4K,theshortcircuitdisappearedimmediately.Oncethetemperaturedropsagain,theshort-circuitphenomenonstilloccurs.Evenreconnectingthelinewillnothelp.SoheimmediatelyreportedtoKamelinOnnes.KamerlinOnnesdidn'tbelieveitatfirst,butherepeatedthisexperimentmanytimes,andfinallyrealizedthatthiswastherealeffectofthedisappearanceoftheresistance.
KamelinOnnesannouncedthisdiscoveryonApril28,1911.Atthistime,hehadn'tseentheuniversalsignificanceofthisphenomenon,justregardeditasaspecialphenomenonrelatedtomercury.OnNovember25th,hemadeareporton"SuddenChangeintheRateofDisappearanceofMercuryResistance",clearlygivingthecurveofmercuryresistance(comparedwithresistanceatroomtemperature)withtemperature.Hesaidinthereport:"Between4.21Kand4.19K,theresistancedecreasedextremelyfast,anddisappearedcompletelyat4.19K."
Between1912and1913,KamelinOnnesItwasalsodiscoveredthattheresistanceoftin(Sn)droppedtozeroat3.8K,andthenitwasdiscoveredthatleadalsohadasimilareffect.Thetransitiontemperaturewasestimatedtobe6K(laterconfirmedtobe7.2K).In1913,KamerlinOnnesdeclaredthatthesematerials"haveenteredanewstateatlowtemperatures,andthisstatehasspecialelectricalproperties."Theterm"superconductivity"isnamedafterKamelinOnnes.
TheresearchresultsofKamelinOnnesarepublishedinthe"JournaloftheRoyalAcademyofSciencesAmsterdam"and"CommunicationsofthePhysicsLaboratoryofLeidenUniversity".Thelatterpublicationwasfoundedbyhimhimselfandmainlypublishedacademicliteratureoncryogenics.
Forhisoutstandingcontributionstolow-temperaturephysics,KamerinOneswontheNobelPrizeinPhysicsin1913.
CharacterEvaluation
Attheendofthe19thcenturyandthebeginningofthe20thcentury,therewasaworldwidecompetitionintheexperimentalresearchoflowtemperature.Inthissensationalsciencecompetition,thecryogeniclaboratoryinLeiden,asmallDutchcity,istheleader.OnesreceivedtheNobelPrizeinPhysicsin1913inrecognitionofhisresearchonthepropertiesoflow-temperaturematerials,especiallythosethatledtotheproductionofliquidhelium.
CommemorationofLaterGenerations
Tocommemoratehim,thePhysicsLaboratoryofLeidenUniversitywasnamed"KamelinOnesLaboratory"in1932.