简介:TheextendedcanonicalNoetheridentitiesandcanonicalfirstNoethertheoremderivedfromanextendedactioninphasespaceforasystemwithasingularLagrangianareformulated.UsingthesecanonicalNoetheridentities,itcanbeshownthattheconstraintmultipliersconnectedwiththefirst-classconstraintsmaynotbeindependent,soaquerytoaconjectureofDiracispresented.BasedonthesymmetrypropertiesoftheconstrainedHamiltoniansysteminphasespace,acounterexampletoaconjectureofDiracisgiventoshowthatDirac'sconjecturefailsinsuchasystem.WepresenthereadifferentwayratherthanCawley'sexamplesandother'sonesinthatthereisnolinearizationofconstraintsintheproblem.Thisexamplehasafeaturethatneithertheprimaryfirst-classconstraintsnorsecondaryfirst-classconstraintsaregeneratorsofthegaugetransformation.
简介:用单辊甩带法制备了不含高生物毒性元素的Ti60Zr10Ta15Si15非晶薄带,并在高于其晶化开始温度的不同温度下对该非晶薄带进行了真空退火,研究了该非晶薄带在磷酸盐缓冲溶液(PBS)中的电化学腐蚀行为及热处理对其显微组织及其电化学行为的影响。结果表明,用单辊甩带法制备的Ti60Zr10Ta15Si15金属薄带为完全的非晶态结构,其玻璃转变温度和晶化开始温度分别为759K和833K,经过878K真空热处理后,薄带发生了部分晶化,在非晶的基底上析出了Ti相;经过938K热处理后,薄带发生了完全晶化,晶化相主要由Ti、Si3Ta5和SiZr以及TiSi组成。动电位极化测试表明,该非晶合金在PBS溶液中可表现出较为优异的耐蚀性能,部分晶化可进一步提高该合金的耐蚀性能,而完全晶化的合金抗腐蚀性能明显下降。
简介:Inordertofacetheexpectedincreaseinstatisticsbetweennowand2005,theBabarexperimentatSLACisevolvingitscomputingmodeltowardadistributedmultitiersystem.ItisforeseenthatdatawillbespreadamongTier-AcentersanddeletedfromtheSLACcenter,Aunifromcomputingenvirommentisbeingdeployedinthecenters,thenetworkbandwidthiscontinuouslyincreasedanddatadistributiontoolshasbeendesignedinordertoreachatransferrateof-100TBofdataperyear,Inparallel,smallerTier-BandCsitesreceivesubsetsofdata,presentlyinKanga-Root[1]formatandlaterinObjectivity[2]format,GRIDtoolswillbeusedforremotejobsubmission.
简介:Asanimportantmulti-functionalmaterialappliedinsurfaceacousticwavedevices,opticalcommunications,laserandoptoelectronicsduetoitsgoodphotoelectricandpiezoelectricproperties,lithiumtantalate(LiTaO3)hasdrawnextensiveinterests[1].NumerousphysicalpropertiesofLiTaO3,suchasacoustical,electronicstructures,opticalpropertiesandeffectivemass,thermodynamicproperties,havebeenreportedinseveralpapers.Pointdefectswillaffecttheelectronicstructurewhichshouldberesponsibleformanyphysicalproperties,especiallyopticalproperties.
简介:Fieldemissionoccurredinsuperconductingradio-frequency(SRF)cavitiesisthemajorobstacleoftheacceleratorsoperatingathighgradient,whichpartlycausedbytheinnersurfacecontamination,suchasthehydrocarbonsandtheabsorbedresidualgas.Theplasmaprocessingcanbeaneffectivemethodtosolvethefieldemissionissues.Thepropertiesoflowtemperatureglowdischarge,whichwasargonplasmawiththechemicallyreactiveoxygen,wereinvestigatedfortheSRFcavitiesusedforCADSproject.
简介:QuantumdynamicscalculationsforthetitlereactionH(2S)+S2(X3-Σg)→SH(X2Π)+S(3P)areperformedbyusingagloballyaccuratedoublemany-bodyexpansionpotentialenergysurface[J.Phys.Chem.A1155274(2011)].TheChebyshevrealwavepacketpropagationmethodisemployedtoobtainthedynamicalinformation,suchasreactionprobability,initialstate-specifiedintegralcrosssection,andthermalrateconstant.Itisfoundnotonlythatthereisareactionthresholdnear0.7eVinbothreactionprobabilitiesandintegralcrosssectioncurves,butalsothatboththeprobabilityandcrosssectionincreasefirstlyandthendecreaseasthecollisionenergyincreases.Theexistenceoftheresonancestructureinboththeprobabilityandcrosssectioncurvesisascribedtothedeeppotentialwell.Thecalculationoftherateconstantrevealsthatthereactionoccurringonthepotentialenergysurfaceoftheground-stateHS2isslowtotakeplace.
简介:Alongwiththedevelopmentsonthehardware'stechniqueoftheLEDelectronicdisplay,thecontrolsoftwarewasalsoaskedtoadvancetoanewlevel.Theoldsoftwareofourcompanycouldn'tdemandnolonger.It'ssatisfythecustomer'snecessarytodesignanewplaysoftwaretoshowtheadvantagesoftheLEDelectronicdisplay.
简介:Theaimofthisexpositionistoprovideadetaileddescriptionoftheuseofcombinatorialalgebrainquantumfieldtheoryintheplanarsetting.ParticularemphasisisplacedontherelationsbetweendifferenttypesofplanarGreen'sfunctions.TheprimaryobjectisaHopfalgebrathatisnaturallydefinedonvariablesrepresentingnon-commutingsources,andwhosecoproductsplitsintotwohalf-coproducts.Thelattergiverisetothenotionofanunshuffiebialgebra.ThissettingallowsadescriptionoftherelationbetweenfullandconnectedplanarGreen'sfunctionstobegivenbysolvingasimplelinearfixedpointequation.Wealsoincludeabriefoutlineoftheconsequencesofourapproachintheframeworkofordinaryquantumfieldtheory.