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:证明了在场强为零势不为零的复连通区域,规范势沿粒子运动闭合路径的不可积积分是Berry几何相位。说明了由规范势构成的不可积相位因子中一部分是几何Berry相因子,并以电磁场为例说明规范场和相位因子的关系。因此不可积Berry相因子最完整地描述了与规范场有关的物理现象
简介:Inthispaper,thetwo-dimensionalMarcinkewiczintegralintroducedbySteinμ(f)(x)=(∫0x|∫|x-y|≤1|x-y|Ω(x-y)f(y)dy|2t-3dt)2isshowntobeofweaktype(1,1)andweightedweaktype(1,1)withrespecttopowerweight|x|"if-1<α<0,whereΩishomogeneousofdegree0.hasmeanvalue0andbelongstoLlog+L(S1).
简介:如果对一个简单图G的每一个与G的顶点数同奇偶的独立集I,都有G-I有完美匹配,则称G是独立集可削去的因子临界图.如果图G不是独立集可削去的因子临界图,而对任意两个不相邻的顶点x与y,G+xy是独立集可削去的因子临界图,则称G是极大非独立集可削去的因子临界图.本文刻画了极大非独立集可削去的因子临界图.
简介:Thereactionof1-phenyl-3-methyl-4-benzoyl-2,5-dihydro-1H-pyrazol-5-one(PMBP)andmethyldithiocarbazate(mdtc)inmethanolresultsinformationofayellowcrystallinesolid,adductof1-phenyl-3-methyl-4benzoyl-2,5-dihydro-lH-pyrazol-5-oneandmethyldithiocarbazate.Whentheyellowsolidsweredissolvedinamixtureofmethanolandether(1:4),aredcrystal,whichisanoxidationproductoftheformer,wasobtainedbyallowingsolventtoevaporateforafewdaysatroomtemperature.TheX-rayanalysisoftheredcrystalindicatesthatitisanoveldisulfidewithaspecialstructurelikea“U”conformationinthesolidstate.
简介:α-Aminonitrileswerepreparedefficientlyfromanodiccyanationofα-aminoester.Theeffectofdifferentsolventsandelectrolyteswasstudied.Theotherbyproductswereanalyzed.