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Jelliummodel377●JJJacobi,MoritzHermannvon(Photo)(Sep.,,Potsdam,Germany–Mar.,,St.Petersburg,Russia)JacobiwasaGermanphysicistandengineerwhoworkedmainlyinRussiaonpracticalap-plicationsofelectricity.Hisresearchonelectromagnetsandtheirapplicationsinelectro-generatorsandelectro-motorswasofgreatpracticalimportance[i].Inhedesignedoneofthefirstelectro-motorsandinheconstructeda-ftboatpropelledbyanelectricmotorwithalargenumberofbatterycells.Itcarriedpassen-gersontheNevaRiver,St.Petersburg,ataspeedofthreemilesperhour.In,Jacobidevelopedgalvanoplas-tics(alsocalledelectrotyping)[ii]–themethodformak-ingduplicateplatesforrelief,letterpress,orprinting.Healsocontributedtothedevelopmentofwiretelegraphy.Refs.:[i]JacobiMH()Mémoiresurl’applicationdel’électro-magnetismeaumouvementdesmachines.EggersetCie,SanktPeters-burg;[ii]JacobiMH()DieGalvanoplastik.EggersetCie,SanktPe-tersburgEKJacobicurrentstrength(intensity)—Obsoletedefini-tionofthestrengthofcurrent.Jacobihassuggestedtouseasaaunitofcurrentstrengththatcurrentwhichpro-ducescmofdetonatinggas(oxygen-hydrogenmix-ture)inoneminute(underdryconditions,atC,andmmHgpressure).FSJander,Gerhart(Universitätsarchiv,TechnischeHochschuleBerlin)(Oct.,,Alt-Döbern,Germany–Dec.,,Berlin,Germany)Janderstudiedchemistryfrom–inMunichandBerlin,wherehereceivedhisPh.D.in.From–hewasassistantofZsig-mondyinGöttingen,wherehehabilitatedinforin-organicchemistry.In/hewasdeputydirectoroftheKaiser-Wilhelm-InstituteofPhysicalChemistryinBerlin(thepositionwasvacantbecausetheNazisforcedtheformerdirectorHabertoleave).JanderhadthechairofchemistryattheUniversityofGreifswaldfrom–,andfromtohewasdirectoroftheInstituteofInorganicChemistryattheTechnicalUni-versityofBerlin(West-Berlin).Janderisknownforhisworkonelectrolytes,nonaqueoussolvents,andde-velopmentofconductometrictitration.Hecontributedtotheacid-basetheoriesbyadvocatingageneralizedsolvo-acid–solvo-basetheory.Ref.:[i]JanderG()DieChemieinwasserähnlichenLösungsmitteln.Springer,BerlinFSJelliummodel—Jelliumisasimplemodelformetals:Thechargeonthemetalionsissmearedintoacon-stantpositivebackgroundcharge,whichdropstozeroatthesurface;theelectronsaretreatedwithindensity-functionaltheory.Duetotheirsmallmasstheelectronsspilloverthesurfaceintotheadjacentphase,andtheirdensityrespondstoanexternalfield.Jelliumhasbeenusedasamodelforthemetalindouble-layertheoryinordertoexplainthedependenceoftheinterfacialca-pacityonthenatureofthemetal.Refs.:[i]BadialiJP,GoodismanJ,RosinbergM()JElectroanalChem:;[ii]SchmicklerW()JElectroanalChem:;[iii]SchmicklerW,HendersonD()ProgSurfSci:WS378Jost,WilhelmFriedrich●JJelliummodel—Figure.Normalizedelectronicdensityn(x)nearthejelliumsurface(fullline);nbisthebulkdensityJost,WilhelmFriedrich(June,,Friedberg,Hessen,Germany–Sep.,,Göttingen,Germany)JoststudiedchemistryattheUniversityofHallefrom–(partlyalsoinMu-nich).InhereceivedhisPh.D.inHalle,andfromtohewasprivateassistanttoM.E.A.Boden-steininBerlin.nhehabilitatedinHannover,andin/heworkedattheMIT,Cambridge.InhewasappointedProfessorofAppliedPhysicalChem-istryattheUniversityofLeipzig,Germany.HeheldPro-fessorpositionsattheUniversityofMarburg(–),atTHDarmstadt(–),andGöttingen(–).Jostcontributedtovariousfieldsofphysicalchemistry;however,forelectrochemistryhisworkondiffusioninsolidsismostimportant.Inthatfieldhepublishedtwoimportantbooks[i,ii].Refs.:[i]JostW()Diffusion.MethodenderMessungundAuswer-tung.Steinkopf,Darmstadt;[ii]JostW()Diffusioninsolids,liquids,gases,rdedn.AcademicPress,NewYorkFSJoule,JamesPrescott(Dec.,,Salford,GreaterManchester,GreatBritain–Oct.,,SalenearManchester,GreatBritain)Joulestudiedthenatureofheatanditsrelation-shiptomechanicalwork(mechanicalequivalentofheat)atManchesterUniversityunderJohnDalton,developedthefirstlawofthermodynamics,madeobservationsonmagnetostriction,foundtherelationshipbetweenelec-tricalcurrentflowingthrougharesistorandthedissi-patedheat(Joule’slaw).BetweenandhestudiedwithWilliamThomson(laterLordKelvin)theexpansionofgasesanddiscoveredtheeffectlaternamedJoule–Thomsoneffect.TheSIunitofenergy(SIde-rivedunits)wasnamedafterhimtohonorhisaccom-plishments.Refs.:[i]CrystalD(ed)()TheCambridgebiographicalencyclope-dia.CambridgeUniversityPress,Cambridge;[ii]LaidlerKJ()Theworldofphysicalchemistry.OxfordUniversityPress,Oxford;[iii]JouleJP()PhilosMag:;[iv]JouleJP()ProcRSoc:RHJoule’slawpower(electrical)Junctionpotentialliquid–junctionpotential