简介：Anewμ3-Otriiron（Ⅲ）complex[Fe3O（OBz）6（CH3OH）3]（NO3）（CH3OH）2（HOBZ=benzoicacid）hasbeensynthesized,itsstructurehasbeendeterminedandvariabletemperaturemagneticsusceptilityhasalsobeenmeasured.Inthemolecule,threeironatomsformedanequilateraltrianglewithu3-Oincenter.ThefittingtothemagneticsusceptibilityshowedthatanintramolecularantiferromagneticexchangeinteractionoccurredbetweenironatomswithJ=-25.51cm-1,andaweakerintermolecularantiferromagneticexchangeinteractionoccurredwithzJ’=-2.30cm-1.
简介：Pureandneodymium-dopedgadoliniumcalciumoxoboratecrystalsofhighqualityweregrownbytheCzochralskimethod.Theorientationofcrystalwaspreciselydetermined,andthesamplesformeasurementswereprepared.Throughsynchrotronx-raytopographyandhigh-resolutionx-raydiffractometry,thetwinstructurewasdiscovered.Somepropertiessuchasthefigureofmeritvalue,anddielectric,piezoelectric,andelasticconstantsweremeausuredalongwithadiscussionoftheanisotropyofthelaserproperties.
简介：At-hyperwheel(t≥3)oflengthl(orW(t)lforbrevity)isat-uniformhypergraph(V,E),whereE={e1,e2,...,el}andv1,v2,...,vlaredistinctverticesofV=∪eii=1lsuchthatfori=1,...,l,vi,vi+1∈eiandei∩ej=P,j∈/{i1,i,i+1},wheretheoperationonthesubscriptsismodulolandPisavertexofVwhichisdifferentfromvi,1≤i≤l.Inthispaper,theminimumcoveringproblemofMCλ(3,W(3)4,v)isinvestigated.DirectandrecursiveconstructionsonMCλ(3,W(3)4,v)arepresented.Thecoveringnumbercλ(3,W(3)4,v)isfinallydeterminedforanypositiveintegersv≥5andλ.
简介：Europium（Ⅲ）-dopedYF3ispreparedbyahydrothermalprocessat200℃.X-raydiffraction（XRD）patternidentifiestheformationofYF3phasewithoutdetectableimpurity.Environmentscanningelectronmicroscopy（ESEM）imageshowstheevensizedistributionofthesampleswithcubicmorphology.TheexcitationandemissionspectraoftherareearthionsdopedYF3areinvestigatedbyfluorescencespectrophotometer.Theexcitationspectrumfor591nmemissionhasseveralexcitationbandsat320,365,386,397and467nm,andthemainpeakvaluewas397nm.TypicalEu3+emissionpeaksat591nm（5D0→7F1）and612nm（5D0→7F2）areobservedwhenexcitedby397nm,andthestrongestemissionis591nm,demonstratingthattherareearthionsoccupythecentrosymmetricalsitesinYF3.
简介：Ca3Y2(BO3)(4):Eu3+黄磷被高温度solid-statereaction方法综合，并且光特征被调查。排放光谱在相应于电的dipoleD-5(0)的613和621nm展出二强壮的红排出物在365nm刺激下面的Eu3+的-F-7(2)转变，原因是Eu3+代替forY3+在Ca3Y2(BO3)(4)的水晶结构占据非中心对称的位置。为613nm的Theexcitation光谱显示黄磷能是有效地激动的由紫外(紫外)(254nm，365nm和400nm)并且蓝色(470nm)光。Ca3Y2(BO3)(4)的排放紧张上的Eu3+集中的效果:Eu3+黄磷被测量，排放紧张与增加Eu3+集中增加的结果表演，然后减少。Ca3Y2(BO3)(4)的CIE颜色坐标:Eu3+黄磷是(0.639，0.357)在15mol%Eu3+。
简介：[Co3(1,2-S2C6H4)3(PPh3)3][CoBr3(DMF)].sol(1,sol=CHCl3,O(C2H5)2,H2O)wasobtainedfromthereactionofCoBr(PPh3)3withNa2(S2C6H4)inchloroform.TheCo3coreinthecationof1exhibitsametal-metalbondedisoscelestriangle,inwhichthetwolongerCo-CobondsarebothbridgedbyS2C6H4ligandsontwosidesofthetriangleplanerespectively,whilethebottomshortCo-CobondisbridgedbythethirdbidentateS2C6H4ligand.Aseriesofpolynu-clearcobaltclustercompoundswithphosphine,thiolateand/orsulphurligandswerepreparedbylowoxidationstateCo+withthiolatesinorganicsolvents.Thesetri-,tetra-,hexa-,heptanuclearclustercompounds1-8withvarioustypesofcrystalstructurescanbeviewedasthecondensedpolynuclearcobaltcomplexesthatthecobaltatomframeworkswithsulphurbridgedwerebuiltthroughthesmalltriangularunitsof[Co3S3nL3](n=1,2)withorwithout[CoL](L=PR3,Br,Cl,5-C5H5)fragments.
简介：Asanimportantmulti-functionalmaterialappliedinsurfaceacousticwavedevices,opticalcommunications,laserandoptoelectronicsduetoitsgoodphotoelectricandpiezoelectricproperties,lithiumtantalate(LiTaO3)hasdrawnextensiveinterests[1].NumerousphysicalpropertiesofLiTaO3,suchasacoustical,electronicstructures,opticalpropertiesandeffectivemass,thermodynamicproperties,havebeenreportedinseveralpapers.Pointdefectswillaffecttheelectronicstructurewhichshouldberesponsibleformanyphysicalproperties,especiallyopticalproperties.
简介：Reactionsofthe6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrilederivative1withα-halo-carbonylcompoundsgavetheortho-substitutedintermediates2a-cwhichwereconvertedintofuro[2,3-b]thiopyrano[4,3-d]pyridines3a-cbyfusionofafuranmoietyunderbasicconditions.Furthercyclizationof3a-cledtoafusionofapyrimidinering,yieldingthetetracyclicproducts6,7and8.Inaddition,condensationof6withvariousaromaticaldehydesaffordedthecorrespondingimines9a,b.Mannichreactionof7gaveproducts10a,b.
简介：R778.32002032307莫尔条纹法(溶液中)测量角膜接触镜后顶焦度的原理分析=PrincipleanalysisonthemeasurementofbackvertexpowerofcontactlensusingMoirefringemethod(insolution)[刊,中]/张吉焱,王莉茹(中国计量科学研究院.北京(100013))//现代计量测试.-2001,9(6).-17-20详述了莫尔条纹法测量角膜接触镜后顶焦度的基本原理以及相应的理论计算,对目前测量角膜接触镜后顶焦度的两种方法即空气中(传统的焦度计)和溶液中(莫尔条纹法)作了比较,并提出了对角膜接触镜后顶焦度量值综合展望。图2参4(李瑞琴)
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![The structure and magnetic properties of μ<b style='color:red'>3</b>-oxotriiron（Ⅲ） complex [Fe<b style='color:red'>3</b>O（OBz）6（CH<b style='color:red'>3</b>OH）<b style='color:red'>3</b>]（NO<b style='color:red'>3</b>）（CH<b style='color:red'>3</b>OH）2](/image/thesis3 "The structure and magnetic properties of μ<b style='color:red'>3</b>-oxotriiron（Ⅲ） complex [Fe<b style='color:red'>3</b>O（OBz）6（CH<b style='color:red'>3</b>OH）<b style='color:red'>3</b>]（NO<b style='color:red'>3</b>）（CH<b style='color:red'>3</b>OH）2")
![[Co<b style='color:red'>3</b>（1,2-S2C6H4）<b style='color:red'>3</b>（PPh<b style='color:red'>3</b>）<b style='color:red'>3</b>]+, A basic triangle unit of some polynuclear molecules](/image/thesis13 "[Co<b style='color:red'>3</b>（1,2-S2C6H4）<b style='color:red'>3</b>（PPh<b style='color:red'>3</b>）<b style='color:red'>3</b>]+, A basic triangle unit of some polynuclear molecules")
![Synthesis of thiopyrano[4',<b style='color:red'>3</b>':4',5']pyrido[<b style='color:red'>3</b>',2':4, 5]furo[<b style='color:red'>3</b>,2-d]pyrimidines](/image/thesis15 "Synthesis of thiopyrano[4',<b style='color:red'>3</b>':4',5']pyrido[<b style='color:red'>3</b>',2':4, 5]furo[<b style='color:red'>3</b>,2-d]pyrimidines")
