简介：

简介：InBaotourareearthtailingsore,thegradeofrareearthisclosetothatoftheraworenearly.Therareearthsarediscardedintailingsdamcausedbyaseriouswasteofresources.Firstofall,thedecompositionproductsofbastnaesite-andmonazite-mixedrareearthtailingsinCaOinreducingatmospherewerestudiedbymeansofX-raydiffraction(XRD).TheresultsshowthatthenormalproductsareCeO_2,Ce_2O_3,Ca_5F(PO_4)_3,andCe_(0.75)Nd_(0.25)O_(1.875),andtherearenoREPO_4andREFCO_3.Secondly,theroastedproductwasextractedinHCl,andtherelationshipamongroastingtime,roastingtemperature,CaOaddition,andextractiontemperaturewasstudiedbythequadraticregression-orthogonalanalysis.Throughanalysis,theoptimumprocessconditionsofmixedrareearthtailingsextractedareobtainedasfollows:roastingtimeof60min,roastingtemperatureof800℃,CaOadditionof30%,extractiontemperatureof80℃,andextractionratioof99.18%.

简介：Soilisheterogeneousandhasdifferentthermalandhydraulicproperties,causingvariedbehaviorinheatandmoisturetransport.Therefore,soilhasanimportanteffectonland–atmosphereinteractions.Inthisstudy,animprovedsoilparameterizationschemethatconsidersgravelandorganicmatterinthesoilwasintroducedintoCLM4.5(CommunityLandModel).ByusingdatafromtheZoigeandMadoisitesontheTibetanPlateau,theabilityofthemodeltosimultaneouslysimulatethedurationoffreeze–thawperiods,soiltemperature,soilmoisture,andsurfaceenergyduringfreeze–thawprocesses,wasvalidated.Theresultsindicatedthat:(1)thenewparameterizationperformedbetterinsimulatingthedurationofthefrozen,thawing,unfrozen,andfreezingperiods;(2)withthenewscheme,thesoilthermalconductivityvaluesweredecreased;(3)thenewparameterizationimprovedsoiltemperaturesimulationandeffectivelydecreasedcoldbiases;(4)thenewparameterizationschemeeffectivelydecreasedthedrybiasesofsoilliquidwatercontentduringthefreezing,completelyfrozen,andthawingperiods,butincreasedthewetbiasesduringthecompletelythawedperiod;and(5)thenetradiation,latentheatflux,andsoilsurfaceheatfluxoftheZoigeandMadoisitesweremuchimprovedbytheneworganicmatterandthermalconductivityparameterization.