学科分类
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108 个结果
  • 简介:我们由在固定联合盒子中在LHC/ALICE使用颜色玻璃冷凝物动力学学习高精力Pb+Pb碰撞的强子复合的伪快分发。在包括pomeron循环在中央快完成控告的强子复合以后,它被发现那比浸透基于计算的为中央Pb+Pb碰撞是大约1500,它显著地小,[?]1700/2500并且与那兼容基于在破碎区域的复合的研究。[从作者抽象]

  • 标签: 大型强子对撞机 高能强子碰撞 POMERON 子环 重数
  • 简介:在旅行波浪转变下面,一些非线性的部分微分方程例如Camassa河边肥沃的低地方程,高顺序的KdV方程,等等,被归结为u″表示的一首integrable颂诗+p(u)(u')2+q(u)=0答案能被给其将军。而且,为多项式联合完全的辨别系统,这些方程的所有单个旅行波浪答案的分类被获得。方程u″0包括的+p(u)(u')2+q(u)=是的方程(u')2=f(u)一种特殊情况,建议方法能也因此被用于很多非线性的方程。这些完全的结果不能被任何间接方法获得。

  • 标签: 数学物理方法 非线性数学物理方程 孤波解 对称群 非线性偏微分方程
  • 简介:theAlternatingSegmentCrank-Nicolsonschemeforone-dimensionaldiffusionequationhasbeendevelopedin[1],andtheAlternatingBlockCrank-Nicolsonmethodfortwo-dimensionalproblemin[2].Themethodshavetheadvantagesofparallelcomputing,stabilityandgoodaccuracy.Inthispaperforthetwo-dimensionaldiffusionequation,thenetregionisdividedintobands,aspecialkindofblock.ThismethodiscalledthealternatingBandCrank-Nicolsonmethod.

  • 标签: 二维空间 分布函数 有限微分方程 边界条件
  • 简介:Thestudyonthedecaypropertiesofnewisotopeslocatedfarfromthebetastabilitylineiscurrentthefocusofnuclearphysics.ForisotopesintheregionZ>82andN<126,-emissionprevailsasradioactivedecaymodeand-spectroscopyisthemostimportanttooltoobtaininformationonthenuclearstructure.IntheheavynucleiregionwithN=124and126isotones,anintruderstate(h9=2.f7=2)8+basedontheattractiveinteractionoff7=2protonsandf5=2neutronshasbeensignificantlyobserved,whichincreasesthebindingenergyofthisconfigurationwithincreasingprotonnumber.

  • 标签: Multi-nucleon TRANSFER REACTIONS
  • 简介:Inthisarticle,thegeneralcentrallimittheoremandBerry-Esseenboundsforfinite-populationU-statisticswithdegreemareestablishedundertheveryweakconditions,TheseresultssubstantiallyimprovethoseofZhaoandChen’s(1987).

  • 标签: BOUNDS BERRY BOREL KERNEL proof FORMULAE
  • 简介:ThepropertiesofPbn(n=2―30)clustersincludingbindingenergies,seconddifferencesinenergy,andHOMO-LUMOgaps,especiallyfragmentationenergiesandionizationpotentials,havebeenstudiedbyabinitiocalculation.ThemainfragmentationproductsofPbn+areshowntobePb+Pbn-1+forn≤14andtwosmallclusterfragmentsforlargeroneswithn>14.ThePb13+appearsfrequentlyastheproductsinthefragmentationsoflargeclusters.Also,thecalculatedionizationpotentialsoftheclustersareconsistentwiththeexperimentdata.

  • 标签: 电离势 碎裂 集群计算 HOMO LUMO 从头计算
  • 简介:Asoneofcandidatesforthefuelcladdingorstructurematerialusedinfourthgenerationfissionandfusiondemonstratereactor,MAXphasehasthepropertiesofbothceramicandmetal,suchashighmeltingpoint,hightemperaturestability,gooderosionresistanceandradiation-damagetolerance[1;2].Maxphaseisaseriesofceramicsofnanolamellarandhexagonalstructure.Mrepresentstransitionelement.Arepresentsthethirdorfourthmaingroupelement.XrepresentNandC.Inthedesignoflead-cooledfastreactor,itisrequiredthatthematerialshouldendurethecorrosionofliquidPb-Bialloy.Therefore,understandingoftheoxidelayersandtheirgrowthmechanismsinLBEisfundamentallyimportantforthedevelopmentofcandidatematerials.

  • 标签: LIQUID Pb-Bi ALLOY
  • 简介:本文针对核辐射探测实验中所获取的实验数据量大、处理复杂的问题,提出了用实验教学软件通过计算机判断所获取的核辐射探测实验数据,为学生做实验时所获取的实验数据的正确与否做出直观、方便、快速的判断,从而提高实验教学质量.

  • 标签: 实验教学软件 核辐射探测 PB8.0 开发 实验数据 计算机判断
  • 简介:UltrasonicvelocitieshavebeenmeasuredinsinglephaseBi1.7Pb0.3Sr2CaCu2O8+xandBi1.7Pb0.3Sr2Ca2O10+xpolycrystallinesamples.Anomalouschangesofbothlongitudinalandtransversevelocitieswereobservednear200K,whichindicatesthatsomestructuralphasetransitiomightoccur.Theelasticconstantsofthesesampleshavebeendeterminedfromthemeasuredultrasonicvelocitydata,whicharemuchsmallerthanthoseofYBa2Cu3O7-yandBaTiO3,manifestingthattheinterlayercoup-lingwilldramaticallydecreasewhenthec-axesoftheunitcellsoftheseperovstite-likemultilayerceramicsincrease.ThevaluesofPoissonratio,however,ofthoseceramicsareveryclose,implyingsimilarinteratomicbondingforces.Correctedtovoid-freestate,theDebyetemperatureofthesematerialsisestirnatedas270±20k.ThetemperaturedependenceofDebyetemperaturesforthesematerialsisalsocalculatedbyusingthesamemethodandreportedforthefirsttime.

  • 标签: ceramic INTERLAYER multilayer longitudinal CONSTANTS Poisson
  • 简介:U-shapedmicro-nanochannelscangeneratesignificantflowdisturbanceaswellaslocallyamplifiedelectricfield,whichgivesitselfpotentialtobemicrofluidicmixers,electrokineticpumps,andevencelllysisprocess.NumericalsimulationisutilizedinthisworktostudythehiddencharacteristicsoftheU-shapedmicro-nanochannelsystem,andtheeffectsofkeycontrollingparameters(theexternalvoltageandpressure)onthedeviceoutputmetrics(current,maximumvaluesofelectricfield,shearstressandflowvelocity)wereevaluated.Alargeportionofcurrentflowingthroughthewholesystemgoesthroughthenanochannels,ratherthanthemiddlepartofthemicrochannel,withitsvalueincreasinglinearlywiththeincreaseofvoltage.Duetothelocaliondepletionnearmicro-nanofluidicjunction,significantlyenhancedelectricfield(asmuchas15foldatV=1VandP0=0)aswellasstrongshearstress(leadingtoelectrokineticflow)isgenerated.Withincreasingexternalpressure,bothelectricfieldandshearstresscanbeincreasedinitially(duetoshorteningofdepletionregionlength),butaresuppressedeventuallyathigherpressureduetothedestructionofiondepletionlayer.Insightsgainedfromthisstudycouldbeusefulfordesigningnonlinearelectrokineticpumpsandothersystems.

  • 标签: U-SHAPED micro-nanochannels ELECTROKINETIC flow MAXIMUM SHEAR
  • 简介:Modelinglog-mortalityratesonO-UtypeprocessesandforecastinglifeexpectanciesareexploredusingU.S.data.IntheclassicLee-Cartermodelofmortality,thetimetrendandtheage-specificpatternofmortalityoveragegrouparelinear,thisisnotthefeatureofmortalitmodel.Toavoidthisdisadvantage,O-Utypeprocesseswillbeusedtomodelthelog-mortalityinthispaper.Infact,thismodelisanAR(1)process,butwithanonlineartimedriftterm.BasedonthemortalitydataofAmericafromHumanMortalitydatabase(HMD),mortalityprojectionconsistentlyindicatesapreferenceformortalitywithO-UtypeprocessesoverthosewiththeclassicalLee-Cartermodel.Bymeansofthismodel,thelowboundsofmortalityratesateveryagearegiven.Therefore,lengtheningofmaximumlifeexpectanciesspanisestimatedinthispaper.

  • 标签: MORTALITY STOCHASTIC forecasting O-U TYPE process
  • 简介:TheelectronicpropertiesandtopologicalphasesofThXY(X=Pb,Au,Pt,PdandY=Sb,Bi,Sn)compoundsinthepresenceofspin–orbitcoupling,usingdensityfunctionaltheoryareinvestigated.TheThPtSncompoundisstableintheferromagneticphaseandtheotherThXYcompoundsarestableinnonmagneticphases.Bandstructuresofthesecompoundsintopologicalphases(insulatorormetal)andnormalphaseswithingeneralizedgradientapproximation(GGA)andEngel–Voskogeneralizedgradientapproximation(GGAEV)arecompared.TheThPtSn,ThPtBi,ThPtSb,ThPdBi,andThAuBicompoundshavetopologicalphasesandtheotherThXYcompoundshavenormalphases.Bandinversionstrengthsandtopologicalphasesofthesecompoundsatdifferentpressurearestudied.Itisseenthatthebandinversionstrengthsofthesecompoundsaresensitivetopressureandforeachcompoundasecond-orderpolynomialfittedonthebandinversionstrengths–pressurecurves.

  • 标签: 结构拓扑 化合物 电子性质 PB AU BI
  • 简介:Threeheterobinuclearcomplexesweresynthesized,namely[Cu(oxpn)Co(L)2](ClO4)2·xH2O(L=2,2’-bipyridyl(bpy),1,10-phenanthroline(phen),and5-nitro-1,10-phenanthroline(NO2-phen)),whereoxpnrepresentsN,N’-bis(3-aminopropyl)oxam-ido.Basedon1R,elementalanalysis,conductivitymeasurementandelectronicspectra,thesecomplexeswerecharacterizedbyanextendedoxamido-bridgedstructurewithCu(Ⅱ)inaplanarenvironmentandCo(Ⅱ)inaoctahedralenvironment.ThesymmetryofthecationisveryclosetoC2v.Thecomplexeswerealsocharacterizedwithvariabletemperature(4~300K)magneticsusceptibility,andthedatawerefitforthesusceptibilityequationderivedfromspinHamilton,H=-2JS1.S2-DSx12byleastsquarestrategy.Theexchangeintegral,J,wasfoundtobe-22.36cm-1(forbpy);-15.45cm-1(forphen);-19.10cm-1(forNO2-phen),indicatingthatthereisaweakantiferromagneticspin-exchangeinteractionbetweenthemetalions.

  • 标签: Oxamido-bridge Copper(Ⅱ)-cobalt(Ⅱ) COMPLEXES MAGNETISM
  • 简介:Anewdi-functionadsorbent(JN-3)waspreparedbysulfhydrylmodified.ComparingwithAmberliteXAD-4andNDA-150,theequilibriumadsorptionforphenolontheJN-3fromaqueoussolutionswastested,perfectadsorptioncapacitywasshown.Pb2+canbealsoremovedbyJN-3becauseofthechelateinteractionbetweensulfhydrylgroupsandmetalions.Thisadsorbentcouldbeusedinremovalofcombinepollutantssuchasphenoliccompoundsandheavymetalionsfromwastestreams.

  • 标签: 氢硫基 化学元素 表面现象 石碳酸 吸附实验
  • 简介:Usingfirst-principlescalculations,wesystematicallystudythedissociationsofO2moleculesondifferentultrathinPb(111)films.AccordingtoourpreviousworkrevealingthemolecularadsorptionprecursorstatesforO2,wefurtherexplorewhytherearetwonearlydegenerateadsorptionstatesonPb(111)ultrathinfilms,butnoprecursoradsorptionstatesexistingatallonMg(0001)andAl(111)surfaces.Thereasonisconcludedtobethedifferentsurfaceelectronicstructures.FortheO2dissociation,weconsiderboththereactionchannelsfromgas-likeandmolecularlyadsorbedO2molecules.WefindthattheenergybarrierforO2dissociationfromthemolecularadsorptionprecursorstatesisalwayssmallerthanthatfromO2gas.ThemostenergeticallyfavorabledissociationprocessisfoundtobethesameondifferentPb(111)films,andtheenergybarriersarefoundtobeinfluencedbythequantumsizeeffectsofPb(111)films.

  • 标签: 第一原理计算 超薄膜 氧分子 无铅 平面波 表面电子结构