简介：Asusersincreasinglybefriendothersandinteractonlineviatheirsocialmediaaccounts,onlinesocialnetworks(OSNs)areexpandingrapidly.Confrontedwiththebigdatageneratedbyusers,itisimperativethatdatastoragebedistributed,scalable,andcost-efficient.Yetoneofthemostsignificantchallengesaboutthistopicisdetermininghowtominimizethecostwithoutdeterioratingsystemperformance.Althoughmanystoragesystemsusethedistributedkeyvaluestore,itcannotbedirectlyappliedtoOSNstoragesystems.Andbecauseusers'dataarehighlycorrelated,hashstorageleadstofrequentinter-servercommunications,andthehighinter-servertrafficcostsdecreasetheOSNstoragesystem'sscalability.Previousstudiesproposedconductingnetworkpartitioninganddatareplicationbasedonsocialgraphs.However,datareplicationincreasesstoragecostsandimpactstrafficcosts.Here,weconsiderhowtominimizecostsfromtheperspectiveofdatastorage,bycombiningpartitioningandreplication.Ourcost-efficientdatastorageapproachsupportsscalableOSNstoragesystems.Theproposedapproachco-locatesfrequentlyinteractiveuserstogetherbyconductingpartitioningandreplicationsimultaneouslywhilemeetingload-balancingconstraints.Extensiveexperimentsareundertakenontworeal-worldtraces,andtheresultsshowthatourapproachachieveslowercostcomparedwithstate-of-the-artapproaches.ThusweconcludethatourapproachenableseconomicandscalableOSNdatastorage.

简介：Here,wereportthesynthesisofhardcarbonmaterials(RH)madefromnaturalricehuskthroughasinglepyrolysisprocessandtheirapplicationasananodeinsodium-ionbatteries.ThestudiesshowthattheelectrochemicalpropertiesofRHsareaffectedbythetreatmenttemperatures,whichdeterminethematerialsmorphology,inparticular,theirdegreeofgraphitizationandextentofcontinuouschannels(nanovoids).Thelatterareaccessibletosodiumionsandsignificantlycontributetochargestoragecapacityoftheproducedanodes.TheRHsobtainedat1600°Cdeliverthehighestreversiblecapacityof276mAhg-1mainlyduetoinsertionofsodiumionsintothenanovoids.Thisworkdeepensthebasicunderstandingoftheinfluenceofthecarbonizationtemperatureonthesodiumstoragemechanism.