简介:Thedistributionofrareearthelement(REE)formsinsoilsisgiveninthepresentpaperonthebasisofsequentialfractionationanddeterminationof34representativesurfacesoilscollectedfromallpartsofChina.ResultsobtainedshowthattheextractionrateofwatersolubleandexchangeableREEhadtheodd-evenphenomenonandthatoforganicallyboundREEfromLatoLutendedtoreducegraduallywiththeincreaseofatomicnumber.ThestabilityofScandtheactivityandenrichmentofTminsoilsareproposed.Furthermore,thepapermakesapreliminarydiscussiononthedifferencesintheconcentrationdistributionofvariousformsofindividualREEinsomesoils.
简介:Chinesefir(Cunninghamialanceolata)andpoplar(Populusspp.)woodmealwerephenolatedinthepresenceofsulfuricacidusedasacatalyst.Theeffectsofreactiontimeandreactiontemperatureonthewoodliquefactionwereinvestigated.Theresultsshowedthatthereactiontemperaturehadthegreaterinfluenceontheresiduecontentthanreactiontime.Additionally,theliquefactioncurvefortheChinesefirandPoplarweresimilaringeneral.
简介:Adsorptionanddesorptionofexogenousrareearthelements(REE)insoilswerestudied.ResultsshowedthatsoilshadstrongadsorbabilityforREEandtherateofadsorptionofREEwasover95%oftheaddedREEinthesetests.ThecharacteristicsofadsorptionisothermscorrespondedwellwiththebothFreundlichandTemkinequations,butdeviatedfromtheLangmuirequation.TheadsorptionofREEtendedtoincreasewiththerisingofsoilpH.AsequentialextractionmethodusedforstudingthedesorptionanddistributionofREEsorbedinsoilsarealsodiscussed.
简介:Endophyticfungiarewidelyfoundinalmostallkindsofplants.Manyendophyticfungicanproducesomephysiologicalactivecompounds,whicharesametooranalogtothoseisolatedfromtheirhosts.Producingphysiologicalactivecompoundsthroughmicrobialfermentationcangiveanewwaytoresolveresourcelimitationandtofindoutalternativesource.Throughthemethodsoforganicsolventextraction,thinlayerchromatography(TLC)andcolumnchromatography,compoundIwasisolated,purifiedfromtheliquidfermentationmetabolitesofthetaxoids-producedendophyticfungi(Alternaria.alternatavar.taxi1011Y.XiangetLUAn-guo)thatwasscreenedfromthebarkofTaxus.cuspidataSieb.etZucc..CompoundIwasidentifiedasonekindoftaxoidstypeIII,basedontheanalyzingresultsbyusingthemethodsofultravioletspectroscopy(UV),infraredspectroscopy(IR),massspectrometry(MS)andnuclearmagneticresonancespectroscopy(NMR).Thisstudyprovidesacompletedmethodforseparationandpurificationoftheendophyticfungiaswellasstructureidentificationofitsfermentationmetabolite