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1.
TiO2 andCeO2 aresemiconductormaterials .TiO2hasthepropertiesofphoto catalysis[1] whileCeO2 hastheabilityofoxygenstorageandcanpromotethedispersionofprecionsmetalsonthesupporter[2 ] .CeO2 TiO2 com plexcompoundwasusedascatalystandspecialfunction almaterial[3~ 5] .ThetraditionalsynthesisofCeO2 TiO2complexcompoundisbyceramicmethodthatusesoxidesasrawmaterialsanditiscalcinedabove 130 0℃[6~ 8] .However ,thestructureandmicrostructureofthecomplexcompoundarenotsuitableforcatalystandfunctionalm… 相似文献
2.
H2 Sisakindofdeadlypoisonousgaswhichex istsextensivelyinpetroleumandchemicalengineeringproductionline .Itsmassconcentrationintheairisre strictedbelow 0 .0 1mg·dm- 3inindustry (≈ 7× 10 - 4volumefraction) [1] .AcertainquantityofH2 SintheLPG (liquefiedpetroleumgas)resultsinthecontainerinvalidatingeasily (Nationalstandardisthatthecon tentofH2 SintheLPGcannotexceed 340× 10 - 6 vol umefraction) [2 ] .ThecontentofH2 Sinsomemineraldepositsisinconnectionwiththetypeofmineralde posits[3] ,soitc… 相似文献
3.
Distribution and Accumulation of Neodymium and Its Effect on Secretion of Progesterone in Mice 总被引:2,自引:0,他引:2
Rareearthelementshavebeenincreasinglyusedinagriculture ,animalhusbandryandfisheryinChinasinceREcanpromotegrowthofcropsandani mals[1,2 ] .However ,studieshaveshownthatoverex posureofREmayhavenegativeortoxiceffectsonor ganisms ,forexample ,inhibitingenzymeactivityandinterferinginmetabolism ,havinghighaffinitytoCa2 bindingsitesanddown regulatingabsorptionandfunc tionofCa2 ,blockingbloodclotting ,inducingpatho histologicallesionsofliver ,aswellasaffectinggo nadalfunction[3~6 ] .Furthermore ,… 相似文献
4.
M 2highspeedsteel (M 2steel)isamaterialwidelyusedintoolsanddies[1,2 ] .M 2steelischarac terizedbyalongsolidificationrangeandcomplexeu tecticreactions ,whichresultsinsegregationofalloy ingelementsandformationofseveraldifferenttypesofcarbidesduringsolidification[3,4 ] .Forconventionallyprocessedhigh speedsteels ,itisinevitablethatacoarsecarbidenetworkwillbeformedduringsolidifi cation .Coarseprimarycarbidestendtoresultinun evencarbidebandsdistributionafterasubstantialamountofhotprocessing[5] .Ma… 相似文献
5.
ДрицМ .Е .[1,2 ] reportedthatscandium ,com paringwiththeotherrareelements ,isthemosteffec tiveadditiontopromotethestrengthofaluminumal loys .Thestrengthofas extrusionAl 6 5Mgalloyrodcontaining 0 .2 %Screaches 4 0 0MPa (σb)and 2 5 0MPa (σ0 .2 ) ,higherthanAl 6 5Mgalloywithoutscandiumonetime .Willey[3] fromAluminumCompa nyofAmericapatentedthefirstaluminumscandiumalloyin 1971.Since 70′soflastcentury ,theformerSovietUnionengagedcompletelyresearchonthepro ductionandapplicationofalum… 相似文献
6.
RE2 Fe14 Ccompoundswithtetragonalcrystalstructureareformedforalmostallrareearthelements(RE ) .Theirmagneticpropertiesareveryclosetothoseofthecorrespondingborides[1~ 5] .Formostofthelightrare earthelements ,La ,Ce ,ProrNd ,itisdifficulttoproducetheRE2 Fe14 Cphase[5~ 7] .Thereasonisthefairlylowtemperature (Tt)ofthesolidstatephasetransformationinthesecompounds .TheydecomposeeasilyintoRE2 Fe17Cxcompoundsathighertemperatures[8,9] .Highcoercivitiescanbeobtainedthroughacontrolledtransformat… 相似文献
7.
MolybdenumDisilicide (MoSi2 )intermetallicspossessesmetallic likeandceramic likeproperties .Studyonitsfrictionandwearcharacteristicshasim portanttheoreticalandpracticalsignificance[1~ 5] .ItisusefultoreinforcetheMoSi2 materialbyusingthesec ondphaseforimprovementofthefrictionandwearcharacteristics[3 ,6] .Hawketal.[3 ] comparedthewearresistanceofMoSi2 withthatofMoSi2 Nbcomposites ,Nb ,aluminides (Fe3 Al,TiAl)andoxidationceramics(Al2 O3 andPS ZrO2 ) ,andfoundthatthewearresis tanceofMoS… 相似文献
8.
Rareearthelements (REEs)areofcertainphysi ologicalactivity .Theycanimprovetheproductivityandqualityofcropsiftheyareusedaptly[1] .Howev er ,thebasicltheoriesneedtobeexploreddeeplythatREESwereapplicated .inagriculture .SomeREEsaresimilartoCainchemicalproper ties ,andtheyhavebeendescribedasCaanalogs[2 ] .Forexample ,thecrystalradiusoflanthanidecationsisin 96 1 1 5 pm ,whichissimilartothatoftherangeofCa2 (99pm) ,especiallythecrystalradiusofNd3 (99.5pm )isclosesttothatofCa2 .REEsoften… 相似文献
9.
Study of Spatial and Temporal Processes of Soil Erosion on Sloping Land Using Rare Earth Elements As Tracers 总被引:2,自引:0,他引:2
Inrecentyears ,tracertechniqueshavebeenshowntobeveryusefulforstudyingtheratesandpat ternsofsoilerosion .Initially ,nuclidetracerswereused[1] .Sincethenthetypesoftracershavebeenex pandedtoincludeatomicbombfalloutradionuclides ,naturallyoccurringradionuclidesandstablerareearthelements (REE) [2~ 5] .Recently ,Burch[6 ] andWallbrinketal.[7] suc cessivelyusedmutipletracersincluding137Cs ,2 10 Pb ,and7Betostudysoilerosionandsedimentsources .Thismethodwaseffectiveforstudyingmediumorlong termaver… 相似文献
10.
Scientistshavepaidmuchattentiontotherareearthelementswithpharmaceuticalactivity[1] .Hydra zonesandtheircomplexeswithtransitionmetalshavebeenstudiedwidelyfortheirpossessionofadiversespectrumofbiologicalandpharmaceuticalactivities ,suchasanticancer ,antitumourandantioxidativeactiv ities ,aswellastheinhibitionoflipidperoxidationandsoon[2 ] .Metalcomplexesofacylhydrazones ,particu larlythecopper(Ⅱ )complexesof 2 pyridinecarboxy laldehyde 2′ pyridylhydrazoneandsalicylaldehydebenzoylhydrazoneshow… 相似文献
11.
BaFBr∶Eu2 +,asphoto gatedholeburningmateri al[1] ,scintillatorcrystallinematerialandX rayimagestoragematerial ,iscalledphotostimulatedluminescence(PSL)material[2 ] .Theimagingplate (IP)madeofthesephosphorsisnowusedwidelyasdisplayoftwo dimen sionalimagescausedbyionizationradiation[3] .Thecommercialapplicationofthesematerialsbe ganin 1983.Becauseofapplicationofthesephospho rs ,theconventionalX rayfilmmaybereplacedbythescreenmadeofPSLphosphors (alsocalledimagingplate ,IP) [4 ] .IPhasnotab… 相似文献
12.
Themetalcomplexesofhydrazideshaveattractedconsiderableinterestowingtotheirantifungalandantibacterialactivities[1 ,2 ] .Theycanalsobeusedasanalyticalreagents[3 ]andextractingagentsformetalsalts[4 ] .Manycomplexesofhydrazideshavebeensynthesizedandcharacterized[5]… 相似文献
13.
Effect of Rare Earths on Fractionation and Transformation of Soil Available Nitrogen 总被引:1,自引:0,他引:1
Chinahasthelargestreservesandproductionofrareearths (RE )intheworld ,andadvancedre searchesonapplicationofREinagriculturehavebeencarriedoutthroughoutthecountry[1] .Moreandmoreattentionhasbeenpaidtotheenvironmentaleffectofthelong termREapplicationsinagriculture ,andtheaccumulationofREintheplant soilsystemhasbe comeoneofthehotresearchtopics[2 ] .Previousstud iesshowthatlessthan 10 %ofthetotalREexistintheexchangeableformwhentheextraneousREareaddedtosoils ,asmostofthemarequicklyabsorbedandfixe… 相似文献
14.
Itiswellknownthatrareearthsesquisulfides(RE2 S3,whereRE =La~Lu)existinseveralpoly morphicstructures[1] .WhileTb2 S3existsintwopoly morphicstructures :αandγ ,Ho2 S3existsinpolymor phicstructure :δandγ[1,2 ] .Theα phasebelongstotheorthorhombicPnmaspacegroup .Theδ phasebe longstothemonoclinicP2 1/mspacegroup .Althoughthethermoelectricandmagneticpropertieshavebeeninvestigatedforα Tb2 S3[3,4 ] ,thosepropertiesarenotofprimaryimportanceforindustry .Incontrast,theγ phase ,whichhasthecu… 相似文献
15.
Influence of Lanthanum on Phosphorus Uptake and Its Chemical Fractions in Rice Crop (Oryza Sativa) 总被引:1,自引:0,他引:1
Plantgrowthisrelatednotonlytothetotalphos phoruscontentinplantbutalsotoitschemicalfrac tions .Someresearchersbelievedthatdifferentchemi calfractionsplayeddifferentrolesinplantgrowth ,andthatplantwithlowerinorganic Pcontenthashigherphosphorusmetabolicpotential[1] .Wang[2 ] foundrareearthelements nitrateincreasesphosphorusuptakebywheat (TritcumaestvicumL .)inHoaglandnutrientsolutionculture .Wahidetal .[3] showedthatrareearthelementsappliedinsoildecreasesphosphoruscontentofcoconutseedlings .Dia… 相似文献
16.
MelttexturingYBCObulksuperconductorexhibitsthecriticalcurrentdensity(Jc)exceeding 1× 10 4 A·cm 2at 77Kandhaspotentialforvariousengineeringappli cations .Recently ,itwasfoundthatREBa2 Cu3Oy(RE :lightrareearthelement)canexhibithigherJcvaluesun derrelativelyhighfieldsduetoasecondpeakthanthatofYBCO[1] .Anditiswidelyacceptedthatthesecondpeakoriginatesfromthepresenceoffield inducedpin ningbyRE rich(12 3)clusters[2 ,3] .MelttexturinggrowthofRE Ba Cu Odependsonthereducedoxygenatmo sphere ,… 相似文献
17.
Thesecondgenerationofhigh temperaturesuper conductingtapesusingYBCO 12 3superconductorhavebeenanattractivesubjectinrecentyears .IncomparisonwithBibasedsuperconductors ,YBCOshowsbetterirreversibility ,lowAClosscapabilityandhighcriticalcurrentdensityJC inhighmagneticfields[1] .However ,owingtoitspropertyofphysicalmetallurgy ,YBCOtapescannotbeproducedbyOPIT(OxidePowderinTube)technique ,whichhasbeenusedinBibasedsuperconductorsuccessfully[2 ] .Fur thermore ,poorintergrainbondinginpolycrys… 相似文献
18.
Gd2 O3isagoodhostmaterialforluminescenceandhasbeenstudiedwelltheseyears .Gd2 O3dopedwithrareearth (RE)ionsisanidealsystemforfunda mentalresearchsuchasenergytransfer[1] .Moreover ,Gd2 O3∶REhasextensiveuse .Especially ,asahighefficientred emissionluminescentmaterial ,cubicGd2 O3∶EuhasbeenwidelyusedinX rayscintillatormaterial ,highdefinitionprojectiontelevisions ,flatpaneldisplaysandphotoelectronicapparatus[2 ,3] .Inthepastcoupleofdecades ,therehasbeenadramaticgrowthofinterestinnanocrystal… 相似文献
19.
Preparation and Characterization of Microporous Nano-Tungsten Trioxide and Its Photocatalytic Activity after Doping Rare Earth 总被引:6,自引:1,他引:5
Recently,heterogeneousphotocatalyticoxidation decompositionoforganiccontaminantshasbeenstud iedkeenlyinvariousfields.WO3isknownasamulti functionalmaterialapplicableforelectrochromicdis playdevice(ECD),semiconductorgassensor,cata lystetal.WO3,whosebandgapenergyhasbeenesti matedtobe2.5eV,hasthepotentialabilitytophoto catalyzeunderirradiationofvisiblelightofwavelength相似文献
20.
CeO2 findswideapplicationsinfuelcells ,andasapromoterinthree waycatalyst(TWC)forautomotiveexhaustcontrol.Thestabilityandoxygenstorageca pacityofCeO2 makeitanidealpromoterinTWCfo rmulations[1,2 ] .Ithasbeenreported[3 ] thatmicrostruc turalstabilityofCeO2 i… 相似文献