简介：<正>Foranyintegersa1,a2,a3,a4andcwitha1a2a3a40（modp）,thispapershowsthatthereexistsasolutionX=（x1,x2,x3,x4）∈Z4ofthecongruencea1x12+a2x22+a3x32+a4x42≡c（modp）suchthat‖X‖=max{|x1|,|x2|,|x3|,|x4|}《p1/2logp.
简介：Wereportthatβ’-Gd2(MoO4)3crystalshavebeengrownbytheCzochralski(CZ)method.Westudiedthegrowthconditionsfoβ’-Gd2(MoO4)3crystal.Acompatisonbetweentheresistance-heatedmethodandradiofrequencyinduction-heatedmethodisdescribed.Also,theinsituobservationofthedomainstructurebythemicroscopeandbysynchrotronradiationX-raytopographyundertheconditionsofDCpolarizationvoltageandtempertaturechangewerecarriedout.Experimentsshowedthatmultidomainstructureincludingferroelectricandferroelasticdomainsoccurredinβ’-Gd2(MoO4)3cystal.Usuallyferroeletiricdomainsappearedintheas-growncrystalandferroelasticdomainsappearedinthepolishedthinnerpiece.BothferroelectricandferroelasticdomainsdisappearedwhenthetemperatureofthecrystalpiecewashigherthantheCurietempperatureTcandtheycouldbereproducedwhenthetemperatureofthecrystalpiecewasloweredbelowTC.WhenaDCpolarizationvoltagerangingfrom150to500Vwasappliedonac-axisβ’-Gd2(MoO4)3piecehavingathicknessof0.5mm,themultidomainwouldgraduallytransformtoasingledomain.Thisresualmeansthatitispossibletomakeaperiodicallypoledβ’-Gd2(MoO4)3crystal.2001ElsevierScienceB.V.Allrightsreserved.
简介：ＥＬＥＣＴＲＯＮ ＴＲＡＮＳＦＥＲ ＢＥＴＷＥＥＮ Ｅｕ３＋ ＡＮＤ Ｃｅ３＋ ＩＮ ＳｒＭｇＦ４ ＭＡＴＲＩＸＥＬＥＣＴＲＯＮＴＲＡＮＳＦＥＲＢＥＴＷＥＥＮＥｕ３＋ＡＮＤＣｅ３＋ＩＮＳｒＭｇＦ４ＭＡＴＲＩＸ￥ＹｉｎｇＷＵ；Ｃｈ...
简介：YbxY1-xAl3(BO3)4(x=0.1,0.07and0)crystalshavebeengrownbythefluxmethod.ThegrowthdefectsofYbxY1-xAl3(BO3)4crystalsweredetectedbyX-raytopography.ItisfoundthattheperfcetionofYbYABcrystalwithlowYbdopantisbetterthanthatwithhighYbdopant.InYb0.1Y0.9Al3(BO3)4crystal,growhtbands,growthboundaries,grown-indislocationsandinclusionswereobserved.Howver,thedensitiesofgrowthdefectsforYb0.07Y0.93Al3(BO3)4andYAl3(BO3)4arelowandnoobviousinclusionsareobservedinthesecrytals.Inaddition,growthtwinswrerdetectedinYbxY1-xAl3(BO3)4crystalbyusingthechemicaletchingmethod.ItisfoundthatthegrowthtwinsoccurfrequentlyinYb0.01Y0.9Al3(BO3)4crystalwhereasnogrowthtwinappearsinYAl3(BO3)4crystal.Basedontheexperimentalobservations,theformationmechanismofgrowthtwinsisdiscussed.Inthemeantime,theeffectivemeasuresforreducingthegrowthtwinsanddefectsareproposed.2001ElsevierScienceB.V.Allrightsreserved.
简介：
简介：Thestructureofpolyimidefrom1,4-bis(3’,4’-dicarboxyphenoxy)benzeneand4,4’-oxydianilinefilmspecimensbeforeandafterhotstretchinghasbeeninvestigatedbyWAXD,DSCandFTIR.AsevidencedbyboththeWAXDandDSCresults,itcouldbebelievedthatstraininducedcrystallizationdidtakeplaceafterhotstretching.Meanwhile,shiftingpositionandsplittingofsomebandpeaksexistedontheFTIRspectrogramswereexplainedintermsoftheclosepackingofchainsandthechangesofinter-molecularcharge-transferinteractionbetweenimidegroupsandaromaticgroupsuponcrystallization.
简介：Theground-stateandthermodynamicpropertiesofquantummixed-spinchainsof1/2-1/2-1-1and3/2-3/2-1-1areinvestigatedbyaquantumMonteCarlosimulationwiththeloop-clusteralgorithm.For1/2-1/2-1-1chain,wefindithastwophasesseparatedbyanenergy-gapvanishingpointintheground-state.For3/2-3/2-1-1chain,thenumericalresultsshowtwoenergy-gapvanishingpointsisolatedbydifferentphasesinitsground-state.Ourcalculationsindicatethatallthesegroundstatephasescanbeunderstoodbymeansofvalence-bond-solidpicture,andthethermodynamicbehavioratfinitetemperaturesiscontinuousasafunctionofparameterα=J2/J1.
简介：Anovelsupportedliquidphasefilmcatalyst:SupportedPdCl2-(n-C4H9)4N+Cl-moltensaltswasfoundtobeaneffectivecatalystwithgoodstabilityforselectivehydrodechlorinationofCCl2F2(CFC-12)toitsalternativesCH2F2andCHClF2.AdditionofCoCl2,GaCl3andCuCl2toPdCl2-(n-C4H9)4N+Cl-modifiesthecatalyticperformanceofsupportedmoltensalts.
简介：
简介：本文探讨（CH3Li）4中键的作用,通过计算,发现（CH3Li）4分子的面甲基结构比顶甲基结构要稳定;指出Li—Li间的成键作用相当强,约为Li2分子中键作用的40%左右,估计（CH3Li）4中的J7Li-6Li值约为1Hz。
简介：这篇论文介绍各向异性的损坏理论的应用程序给形成A12024T3铝合金表的限制图的学习。在限制铝板结构的紧张的预言，一个有限元素房间模型被构造了。房间模型由二个阶段，铝合金矩阵和金属间化合的簇组成。铝合金矩阵的材料行为与充分联合的elasto塑料的损坏被描述组成的方程。金属间化合的簇被假定有弹性、易碎。由改变拉长的比率，在二轴的拉长下面的表的限制紧张被使用建议的necking标准预言了。预言在对试验性的调查结果的好同意。而且，有限元素房间模型能为理解铝合金的显微镜的损坏机制提供信息。如果材料损坏的效果在形成学习的表金属被忽略，限制紧张的在评价上可以结果。
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：Yb3+complexeswithtwonitrilotriaceticacidmoleculeswerepreparedandtheircompositionsweredeterminedasK3[Yb(nta)2(H2O)]*5H2OandNa3[Yb(nta)2]*6H2Obyelementalanalyses.Theirstructureswerecharacterizedbysingle-crystalX-raydiffractionanalyses.IncomplexK3[Yb(nta)2(H2O)]*5H2O,theYbN2O7partformsanine-coordinatemonocappedsquareantiprismaticstructure.IncomplexNa3[Yb(nta)2]*6H2O,theYbN2O6partformsaneight-coordinatesquareantiprismaticstructure.Itcanbeseenthattheoutercations(K+andNa+)greatlyaffectthecoordinationnumberandcoordinatestructurefromtheseresults.
简介：ConsideringthatKBe2BO3F2(KBBF)isanoutstandingdeepultravioletcrystalwhichcangeneratetheshortestwavelengthsinsecondharmonicgenerationandsum-frequencygeneration,wereportthedeterminationofthenonlinearopticalcoefficientsoftheKBBFcrystal.Thed11coefficientwasdeterminedtobe0.49pm/VbytheMakerfringesmethodatthewavelength1064nm,whichisinagreementwellwiththetheoreticalvalue.
简介：The2-C,methylenegroupof1-aroyl-1,2-dihydro-3H-naphtho[2,1-b]pyran-3-ones(2)havebeenshowedtopossessasuperiorreactivitytowardsmanyoforganicreagents.Thena-phthopyrones(2)condensedwitharomaticaldehydestogivethe2-arylidinederivatives(3).Bromin-ationof2gave1,2-dibromo(4)or5-bromo(5)derivativesdependingonthereactionconditions.Thebasecatalyzedadditionorcycloadditionofnaphthopyrones(2)to4-methoxybenzalacetophenonegavetheexpectedMichaeladduct(6)orthecyclicadducts(7-9)dependingonthetypeofcatalyticbaseandreactionconditions.Structuresoftheproductshavebeenestablishedbyelementalanalyses,IRand~1HNMRspectroscopicmethods.
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4-alkoxy-2,3,5,6-tetrafluorophenyl)ethynyl]benzoates" title="The synthesis and phase transition of 4’-methylphenyl 4"-[(4-alkoxy-2,3,5,6-tetrafluorophenyl)ethynyl]benzoates">
![Synthesis and Characterization of Surfactant-encapsulated Polyoxoanions: [(CnH<b style='color:red'>2</b>n+1)<b style='color:red'>2</b>N（CH<b style='color:red'>3</b>）<b style='color:red'>2</b>]12[Mo36（NO）<b style='color:red'>4</b>O108（H）<b style='color:red'>2</b>O)16] （n=12, 18）](/image/thesis9 "Synthesis and Characterization of Surfactant-encapsulated Polyoxoanions: [(CnH<b style='color:red'>2</b>n+1)<b style='color:red'>2</b>N（CH<b style='color:red'>3</b>）<b style='color:red'>2</b>]12[Mo36（NO）<b style='color:red'>4</b>O108（H）<b style='color:red'>2</b>O)16] （n=12, 18）")
![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）<b style='color:red'>2</b>](/image/thesis16 "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）<b style='color:red'>2</b>")
![Syntheses and Structural Researches of Yb^<b style='color:red'>3</b>＋ Complexes with Nitrilotriacetic Acids—Nine—coordinate K<b style='color:red'>3</b>[Yb（nta）<b style='color:red'>2</b>（H<b style='color:red'>2</b>O）]·5H<b style='color:red'>2</b>O and Eight—coordinate Na<b style='color:red'>3</b>[Yb（nta）<b style='color:red'>2</b>]·6H<b style='color:red'>2</b>O complexes](/image/thesis17 "Syntheses and Structural Researches of Yb^<b style='color:red'>3</b>＋ Complexes with Nitrilotriacetic Acids—Nine—coordinate K<b style='color:red'>3</b>[Yb（nta）<b style='color:red'>2</b>（H<b style='color:red'>2</b>O）]·5H<b style='color:red'>2</b>O and Eight—coordinate Na<b style='color:red'>3</b>[Yb（nta）<b style='color:red'>2</b>]·6H<b style='color:red'>2</b>O complexes")
![A novel <b style='color:red'>2</b>-C reactivity studies of 1-aroyl-l,<b style='color:red'>2</b>dihydro-<b style='color:red'>3</b>H-naphtho[<b style='color:red'>2</b>,1-b]pyran-<b style='color:red'>3</b>-ones](/image/thesis19 "A novel <b style='color:red'>2</b>-C reactivity studies of 1-aroyl-l,<b style='color:red'>2</b>dihydro-<b style='color:red'>3</b>H-naphtho[<b style='color:red'>2</b>,1-b]pyran-<b style='color:red'>3</b>-ones")