简介：Inthispaper,thedualmixedmethodforanunilateralproblem,whichisthesimplifiedmodellingofscalarfunctionforthefriction-freecontactproblem,isconsidered.Thedualmixedproblemisintroduced,theexistenceanduniqenessofthesolutionoftheproblemarepresented,anderrorboundsO(h^3/4)andO(h^3/2)areobtainedforthedualmixedfiniteelementapproximationsofRaviart-Thomaselementsfork=0andk=1respectively.

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简介：Byintroducingthegeneralizedquasi-symmetryoftheinfinitesimaltransformationfortransformationgroupG,,thispaperstudiestheconservationlawsandsymmetriesofdynamicalsystemswithunilateralconstraintsinphasespace.Noether’stheoremandNoether’sinversetheoremforme-chanicalsystemswithunilateralconstraintsinphasespaceareobtainedandtwokindsofequivalentformsofgeneralizedKillingequationswhichareusedtodeterminethe8eneratorsoftheinfinitesimalgrouptransformationaregiven.

简介：Objective:Toretrospectivelyanalyzetheeffectofunilateralexternalfixatorsinthetreatmentoflowerthirdhumeralshaftfractures.Methods:FromOctober1997toOctober2003,33patientsaged15-70years(average31years)withlowerthirdhumeralshaftfracturesweretreatedwithunilateralexternalfixators.Therewere9spiralfractures(typeA1),1obliquefracture(typeA2),3transversesfractures(typeA3)and20comminutedfractures(11typeB1,9typeB2)accordingtoAOclassification.Fifteencasesweretreatedwithopenreductionandlimitedinternalfixationandfixationwithexternalfixators,10casestreatedwithopenreductionandfixationwithexternalfixators,and8casestreatedwithclosedreductionandfixationwithexternalfixators.Nerveexplorationwasundertakenin9caseswithpreoperativeradialnerveinjury.Externalfixatorswereremovedafterbonehealing.Theaveragefollow-upwas18monthswitharangefrom8to24months.Results:Thetimeofbonehealingranged11-22weeks(average14weeks).Thelatestfollow-upshowedthefunctionsof9casesofpreoperativeradialnerveinjuryandof2casespostoperativeradialnerveinjuryandthefunctionofelbowwererecoveredtonormal.Therewereonly7casesofsuperficialinfectionatpinhole,whichwassubsidedbyusingoralantibioticsandpin-holecarewithmilddisinfectants.Conclusions:Fixationwithunilateralexternalfixatorscombinedwithopenreductionandlimitedinternalfixationhasagoodeffectinthetreatmentoflowerthirdhumeralshaftfractures.