Preparation and Long Persistence Red Luminescence of M_ (0.2)Ca_(0.8)TiO_3∶Pr ~(3 ) (M=Mg~(2 ), Sr~(2 ), Ba~(2 ), Zn ~(2 )

Inthe 1990s ,newaluminatelongafterglowphos phorswerereported ,theluminescenceintensityandtheafterglowpersistencearemuchhigherthanthatofthetraditionalsulfide .Moreover ,theydonotcontainradiativeelementandhasgoodstructuralstability .Therehasbeenincreasinginterestonthenewphos phorsovertheworld .Thewideanddeepresearchonthisnewmaterialhasbeenmadeinrecentyears[1～ 3] .Nowadays ,thegreenandbluephosphorescencephos phorscanbesuccessfullypreparedwhichlastsmorethan 30and 12hrespectively[4 ] .Ithasalread…     

Effect of TSL and PSL in Al~(3+)-Doped BaFBr∶Eu~(2+) at Difference Synthesis Conditions

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…     

A Study of Two-Phase Nanocrystalline Nd_(8.5)Fe_(75)Co_5Cu_1Zr_3Nb_1B_(6.5)Permanent Magnet

Materialswithenhancedremanentmagneticpo larizationwereinitiallypreparedbyCoehoorn[1] frommelt spunNd3.8Fe77B19.2 ribbonsbyheattreatment .Thesimilarbehaviorwasalsoobservedfrommelt spuntwo phasesamplesofNd2 Fe14 Bandα Fe[2 ] .Themag neticpropertiesofisotropicnanocrystallinetwo phasepermanentsdependsensitivelyonmicrostructuralfea tures,suchasdistributionofmagneticallyhardandsoftphases ,meangrainsize ,particleshapeandgrainboundarytype[3] .Inordertoobtainhighmaximumenergyproduct ,itisnecessaryt…     

Conductivity of K_(10)H_3[Dy(SiW_4Mo_7O_(39))_2] Treated by Chemistry-Heated Diffusion of Sm and Gd Permeation

Inthelastfewyears ,theapplicationsofpolyox ometalates (POMs)havereceivedmuchattention[1～ 3]fortheiruniquestructuresandproperties ,however ,thepreparationofthemareallofsolid solidorliquid liquidreactions[1] .Fromtheknowledgeoffundamen taltheory ,wethinkthatrareearthelementscanbepermeatedintoPMOsthroughthesolid gasinterfacereaction ,andtoourknowledgethiskindofexperi menthasnotbeencarriedoutuntilnow .Inthispaper ,thechemistry heateddiffusedperme ationmethod[4 ] wasusedtotreatK10 H3[Dy(SiW4 M…     

Study on Spectra of La_2CaB_(10)O_(19)∶Eu~(3 ) in VUV-VIS Range

Manyboratesareexcellenthostsforrareearthlu minescence ,forexample ,nowbestredphosphorinplasmadisplaypanel (PDP )is (Y1-xGdx)BO3∶Eu[1] .Boratephosphorsdopedwithrareearthionshavebeenrichlystudiedinthepastfewdecades[2 ,3] .RecentlyWuYichengetal .[4 ] synthesizedanewbo rateLa2 CaB10 O19,whichispotentialnonlinearopticalmaterials.InthisworkweselectedLa2 CaB10 O19ashostofluminescencematerialsbecauseitprobablyisabetterhostforrareearthluminescence .Duetotherequirementofplasmadisplaypenal(PDP)…     

A New Combustion Process for Nanosized BaCe_(0.95)Y_(0.05)O_(3-δ) Powders

ABO3perovskite typeoxidesdopedwithsometrivalentcationsarenowwellknownashightempera turetypeprotonconductorswithhightransportnumberofprotons .Especially ,theserareearthelement dopedABO3perovskiteoxideswithA =Ca ,Sr ,Ba ,B =Ce ,Zr ,andTi ,etc .havebeenstudiedindetail[1～ 4 ] .Suchperovskitematerialshavereceivedgreatinterestinmanyapplicationareassuchasfuelcells ,sensors ,steamelectrolyzers ,hydrogenseparationfromhydro gencontaininggasmixturesandmembranereactorsforthetransportofprotons[5～ 8]…     

SrAl_2O_4∶Eu~(2+),Nd~(3+) and Dy~(3+) Long Afterglow Phosphor

Longafterglowphosphorabsorbingenergyfromsolar,lampandotherlightsourcesforashorttimestorestheenergyandexhibitsbrightandlong lastingphosphorescencewhichsuitsthevisualperceptionofthehumaneyewithminimumbrightness 0 32mcd·m- 2 andlastingtimemorethan 8h) .TheSrAl2 O4 ∶Eu2 +,Dy3+phosphorhasbeenknowntobeagreenlongafterglowphosphorwithanemissionpeakat 5 2 0nm[1～ 7] .ThepropertiesofthephosphorwerefurtherexaminedbythegroupofTangMingdaoandMatsuzawaTindetailin 1995and 1996respectively[1,2 ] .Inorde…     

问与答——测量与控制(二)

问题1.压力测量图示U型管中压力差P_1-P_2是多少?[Ⅰ]约300mbar:[Ⅱ]约270mbar;[Ⅲ]约222mbar; [Ⅳ]约30mbar;[Ⅴ]约27mbar2.压力测量下列压力计中,哪种适于测显微小压     

Research of Colossal Magnetoresistance in La_(0.67)Ca_(0.33)Mn_(1-x)Cr_xO_3 (0.00x0.15)

Inthelastfewyears ,agreatdealofworkhasbeendevotedtothemixed valencemanganitesLn1-yAyMnO3(Ln =rareearthelements ,A =Ca ,Sr ,Ba)exhibitingcolossalmagnetoresistance (CMR ) [1～ 3] .Aprominentfeatureofthesematerialsisametallic insu latingtransitionassociatedwiththeferromagnetic paramagnetictransition .Earlyworkhadrevealedthesignificanceofthedouble exchangeinteractionthroughMn3 O Mn4 networkintheclosecorrelationbe tweenthetransportandthemagnetism[4 ,5] .However ,recentdetailedstudieshaves…     

Luminescence Properties of (Y, Gd)Al_3(BO_3)_4∶Eu ~(3 ) under VUV excitation

Thephosphorsasanimportantpartofplasmadis playpanel (PDP)deviceemitvisiblelightundervac uumultraviolet (VUV)excitationof 14 7nmand/or172nmfromXe/Hegasplasma[1] .Untilrecently ,Y2 O3∶Eu3 and (Y ,Gd)BO3∶Eu3 havebeenusedascommercialred emittingphosphorsforPDP[2 - 3] .Butthesematerialsstillhaveshortcomingstobeim proved :lowlightoutputofY2 O3∶Eu3 uponVUVex citationandbadcolorpurityof (Y ,Gd )BO3∶Eu3 [4～ 5] .AluminoborateshavestrongabsorptionintheVUVregion ,andexhibitexcellentma…     

Giant Low-Field Magnetoresistance in Polycrystalline La_(2/3)Ca_(1/3)Mn_(1-x)Cu_x O_3 Sintered at 1100 ℃

Themixed valenceperovskitemanganiteRE1-yAyMnO3(RE =rareearth ,A =alkalineearth)systemisoneofthemoststudiedtopicsduetoitsunusualmagneticandtransportproperties ,especiallythecolossalmagnetoresistance (CMR)effect[1,2 ] .CMRisfoundonamagneticfieldscaleofseveralteslas ,whichisnotveryappealingforapplications .Accord ingly ,manyresearchgroupsfocusedontheinvestiga tionofextrinsicmagnetoresistanceeffectsfoundinvar iousmagneticoxides[3,4 ] ,sincethesepromisedalargemagnetoresistanceratioinlowfields …     

Synthesis,Characterization and Luminescent Properties of Complexes of Rare Earth Nitrates with Tris{2-[N-(pyridine-methanoyl)amino]ethyl} amine

Duringthelastdecade ,thedesignandsynthesisoftripodalligandsandtheirmetalcomplexeshaveattractedconsiderableattentionduetotheirpotentialusesaslumi nescentprobesinmedicineandbiochemistry[1～ 7] ,ascatalysts[8] andelectrochemicalmaterials[9] .However ,thecomplexesofrareearthmetalwithtripodalligandshavefewreported[10 ] .Asanextensionofourstudiesoncomplexesofmetalwithtripodalligands ,anewtripodalligand (tris { 2 [N (pyridine methanoyl)amino]ethyl}amine ,L)anditscomplexeswithrareearthnitratesweresyn…     

Luminescence and Energy Transfer Properties of Ca_2Gd_8(SiO_4)_6O_2∶A(A=Pb~(2 ), Tm~(3 ))Phosphors

Compoundswiththeapatitestructureareverysuit ablehostlatticesforvariousluminescentions .ThemostwellknownexampleisSb3 andMn2 coactivatedcalci umhalophosphateCa5(PO4 ) 3(F ,Cl)∶Sb ,Mn ,whichhasfoundapplicationsinfluorescentlampsforalongtime[1] .Ca2 R8(SiO4 ) 6 O2 (R =Y ,Gd ,La)isakindofternaryrare earth metalsilicatewiththeoxyapatitestructure ,whichhasbeenusedashostmaterialsfortheluminescenceofvariousrareearthandmercury likeions[2～ 4 ] .Themostprominentstructuralcharacteristicisthetwos…     

Synthesis and Luminescence Properties of Gd_2O_3∶Eu~(3+) Phosphors

Gd2 O3∶Eu3+ isanefficientredemittinglumines centmaterial ,whichcanbeappliedindisplays[1,2 ] .TheconventionalcommercialGd2 O3∶Eu3+ ismainlysynthesizedbyhightemperaturesolid statereactionandchemicalco precipitationmethods .Anadvancedperformanceofdisplaysrequireshighqualityphospho rssuchashighbrightnessandefficiency ,monodisper sityandfinegrainsize .Muchresearchhasanticipatedthatsubmicrometer sizedandnanometerluminescentmaterialswillhavethesepotentialadvantages[3～ 8] ,sosubmicrometer sizedan…     

问与答——测量与控制(四)

1.温度测量 下面对热电偶温度计的叙述哪个是正确的? [Ⅰ] 与电阻温度计相比,抗振动性差。 [Ⅱ] 与电阻温度计相比,检测滞后小。 [Ⅲ] 与电阻温度计相比,允许误差小。 [Ⅳ] 热电偶和接收仪表联接时,若设法补偿冷端温度变化(采用带有冷端补偿装置的仪表),则可以不用补偿导线而用普通导线。     

Preparation and Luminescence Properties of the New Long Phosphorescent Phosphors Ba_(1-x)Ca_xAl_2O_4∶Eu ~(2 ), Dy~(3 )

Inrecentyears ,SrAl2 O4 ∶Eu2 ,Dy3 ,CaAl2 O4 ∶Eu2 ,Nd3 [1～ 8] andBaAl2 O4 ∶Eu2 ,Dy3 [9]havebeenconsideredasusefulblueandgreenphos phorsbytheirlongdurationphosphorescence .Howev er ,toourknowledge ,thephosphorBa1-xCaxAl2 O4 ∶Eu2 ,Dy3 hasnotbeeninvestigated .TheluminescenceofEu2 isverystronglydepen dentonthehostlattice ,whichcanoccurfromtheul traviolettotheredregionoftheelectromagneticspec trum .Itiswellknownthatthepersistentluminescenceisduetothetrappingofenergyinthed…     

用取代二烷基的二膦酸萃取U(Ⅵ)和Sr(Ⅱ)

E.O.Otu等通过测定 2 5～ 60℃温度范围内的金属的分配比 ,研究了用 P,P’-二 (2 -乙基己基 )亚甲基二膦酸 (H2 DEH[MDP] ) ,P,P’-二 (2 -乙基己基 )亚乙基二膦酸 (H2 DEH[EDP] )和 P,P’-二 (2 -乙基己基 )亚丁基二膦酸 (H2 DEH[Bu DP] )的邻二甲苯溶液从硝酸溶液中萃取 U ( )和 Sr( )的热力学。研究结果表明 ,萃取剂的团聚和萃取计量不随温度变化而改变。对 3种萃取剂 ,U( )的萃取受熵与焓的变化驱动 ,而 Sr( )的萃取 ,用 H2 EDH[MDP]时受焓变驱动 ,用 H2 DEH[EDP]和 H2 DEH[Bu DP]时受熵变驱动。这与萃取 Am( )…     

Ce_xTi_(1-x)O_2 Mixed Oxides Supported CuO Catalyst for NO Reduction by CO

Uptodate ,numerousstudieshaveshownthatrareearthoxidesaretheexcellentstructuralandelec tronicpromoterstoimprovetheactivity ,selectivityandthermalstabilityofcatalysts[1,2 ] .Themostwidelyappliedrareearthoxideinindustrialcatalysisiscer tainlyCeO2 .However ,amajordrawbackofCeO2 isthelossofoxygenstoragecapability (OSC)duetoitssinteringathighertemperature (>75 0℃ ) ,whichleadstothedeactivationofthecatalyst[3 ,4] .Oneap proachpreviouslyusedtostabilizeceriaagainstsinter ingwastodopeitwithotheranti…     

Effects of Interlayer Composition on Bond Strength and Interfacial Microstructure of Green Joined CePO_4-ZrO_2 Ceramics

Themethodsinceramicjoiningincludeactivemetalbrazing[1,2 ] ,diffusionbonding[3] ,pyrolysisofpreceramicpolymers[4 ,5] ,combustionreaction[6 ] ,andjoiningbymicrowaveheating[7～ 9] .Atpresent ,twopromisingmethodsforjoiningadvancedceramicsarebrazinganddiffusionbonding[10 ] .Thefillingmaterialscanbemetals ,alloysorglasses[11] .However ,thestrengthofthejointsatelevatedtemperatureisratherlowbecauseoftherelativelylowsofteningtemperatureofthemostcommonlyusedalloyinterlayermaterials .Formaterialsjoinedwi…     

Lanthanum Relieved Toxic Effects Caused by Nickel in Hydrocharis dubia B L. Backer Leaves

Rareearthelementshaveextensivelybiologicaleffectsonplants ,animalsandhumanbeingsinthebiosphere[1,2 ] .Researchershavefoundthatrareearthelementscouldpromotetheresistanceofplantagainstsalt[3] ,inundation[4 ] ,aridity[5] andacidrain[6 ] etal .However ,fewreportswereontheirabilityofrelievingthestressofheavymetaltotheplant .Lanthanum(La) ,asanimportantrareearthelement ,alwayspar ticipatesinorinterfereswiththeprocessofbiologicalreactions[7] .ThispapermainlydealtwiththeeffectsofLaonHydrocharisdubia…