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Vol. 51, No. 1 (2002)

2002-01-05
GENERAL
Li Ren-Jie, Qiao Yong-Fen, Meng Jun
2002, 51 (1): 1-5. doi: 10.7498/aps.51.1
Abstract +
Inthispaper,theGibbs Appell (G A)equationsforvariablemassholonomicsystemswereestablished ,thenthedefinitionandcriterionoftheforminvarianceofG Aequationsundertheinfinitesimaltransformationsofgroupsweregiven .Next,acon servedquantitycanbededucedbyusingthisforminvarianceundercertainconditions,andanexamplewasgiven
Liu Tian-Gui, Yan Jia-Ren, Pan Liu-Xian
2002, 51 (1): 6-9. doi: 10.7498/aps.51.6
Abstract +
Inthispaper,inafirst orderapproximation ,weobtaintheeffectsofperturbationsonastationarysolitonforTDGLE (timedependentginzburg landauequation) .Namely ,weobtainthesolitonparametervariationandthegeneralexpressionofthefirst or dercorrection .Atthesametime,wegivetheexactexpressionofaspecialexample
Liu Shi-Kuo, Fu Zun-Tao, Liu Shi-Da, Zhao Qiang
2002, 51 (1): 10-14. doi: 10.7498/aps.51.10
Abstract +
InthispapertheJacobiellipticfunctionexpansionmethodisextendedtothefiniteexpansionfortheappliedJacobicosineellipticfunctionorthethirdkindofJacobiellipticfunctiontoconstructthenewperiodicsolutionsofnonlinearwaveequations.Theperiodicsolutionsobtainedbythismethodcanbereducedtothesolitarywavesolutionsunderthelimitcondition.
Zhang Quan, Tang Chao-Jing, Gao Feng
2002, 51 (1): 15-20. doi: 10.7498/aps.51.15
Abstract +
Quantumerrorcorrectioncodingtechnologyisofgreatimportanceforquantumcommunicationaswellasquantumcomputa tion .Nearlyalloftheclassicalerrorcorrectioncodingschemeshave ,forthetimebeing,beentransplantedtothedomainofquantuminformation ;nevertheless,themostoutstandingschemeinclassicalcodingregion ,turbocode ,stilllacksthequantumanalo gytillnow .Wehavecompletedasimpleschemeofquantumrecursivesystematicconvolutionalcodebymeansofquantumregisternetwork .Atthesametime,akindofefficientquantuminterweaverisconstructedusingonlyquantumSWAPgates.AlsoaseriallyconcatenatedquantumTurbocodeisdevelopedbyanalogytotheclassicalTurbocode .Aslimitedbythequantumnon -cloningtheorem ,theproposedquantumturbocodeisseriallyconcatenated .Quantumturbocodemaynotonlyextendtheresearchareaofquantumerrorcorrectioncodingtechnology,butalsosolvethepuzzleinclassicalcodingtheory.
Zhao Ren, Zhang Chun-Li
2002, 51 (1): 21-24. doi: 10.7498/aps.51.21
Abstract +
Byusingthemethodofquantumstatistics,wedirectlyderivethepartitionfunctionofthebosonicandermionicfieldonblackplaneandobtaintheintegralexpressionoftheblackplane’sentropy,whichavoidsthedifficultyinsolvingthewaveequationofvariousparticles.Thenviatheimprovedbrick -wallmethod,membranemodel,wecalculatetheblackplane’sentropyandfindoutthatifwelettheintegralupperandlowerlimitsbothtendtothehorizon ,theentropyoftheblackplaneisproportionaltotheareaofhorizon.Inourresult,thestrippedtermandthedivergentlogarithmictermintheoriginalbrick -wallmethodnolongerexist.Inthewholeprocess,wedonottakeanyapproximation .Weofferanewsimpleanddirectwayofcalculatingtheentropyofdifferentcomplicatedblackholes.
Cao Zhi-Jue
2002, 51 (1): 25-30. doi: 10.7498/aps.51.25
Abstract +
Dynamicdescriptionisgivenofthephenomenaofdropletcondensation .Thechangeofthechemiclpolentialisdiscussedfortwotypesofliquiddroplets.TheconditionfortheBrownaggregationtooccurisalsoobtained .Combiningallthesewiththedropoffradius,theoptimalcomtactanglecanthenbedetermined.
Chen Guang
2002, 51 (1): 197-200. doi: 10.7498/aps.51.197
Abstract +
ThecollapsesolutionofastarwithuniformdensityandzeropressuregivenintheclassicpaperofOppenheimerandSnyderisprovedtobeincomplete;itcannotcorrectlyconnecttheFriedmannandSchwarzschildmetricsastheinteriorandexteriorsolutions.Bytheextensionofsolutionparameterinthediscretespacetime,weconstructacompletegravitationalsolution ,whichcouldmakeanequivalenceconnectionbetweentheFriedmannandSchwarzschildmetricsandisprovestobesingularity free.Thesolutionshowsthatthereexistsarelationshipamongmatter,gravitationanddiscretespacetimeconfiguration .
ATOMIC AND MOLECULAR PHYSICS
Xu Xiu-Lian, Wang Feng, Zhang Feng-Shou, Zeng Xiang-Hua
2002, 51 (1): 31-35. doi: 10.7498/aps.51.31
Abstract +
Usingthedistance dependenttight bindingmoleculardynamicsmodel(DDTB MD) ,theNa6 (2D) +Na8,Na6 (3D) +Na8collisiondynamicprocesseshavebeenstudiedfordifferentincidentenergiesanddifferentimpactparameters.Differentreactionmechanismshavebeenobserved ,suchasfusionreaction ,deepinelasticandquasi elasticcollisions,whicharesimilartothenuclearheavy ioncollisions.Thisshowsthattheclusterswithdifferentgeometricstructurescollidingwithidenticalclusterscanproducedifferentnewclusters.Atlowerincidentenergycentralcollisions,Na6 (3D)canformastablecluster;atleV nhalfcentralcollision ,Na6 (3D)iseasytoformalargercluster.
Zhang Xiang-Yang, Li Yong-Fang, Sun Jian-Feng, Wang Yong-Chang
2002, 51 (1): 36-41. doi: 10.7498/aps.51.36
Abstract +
WepresentanewQuasi Λ model four levelsystembasedonageneralthree levelΛ modelandinvestigatetheresonantfluorescencespectroscopyindetail.Therearethreeultra narrowspectrallinesinthespontaneousemissionspectrafromupperleveltolower lyinglevelsofthetwoemissionchannels,whichoccuroverawiderangeoftheparameters.Theappearanceofthethreeultra narrowspectrallinesiscloselyrelatedwithRabifrequencyofthetwocoherencedrivingfields;andthelargertheRabifrequency ,thenarrowerthelines.Theeffectoflinenarrowingdoesn’toccurwhenthereisonlyacoherencedrivingfield .Whiletheincoherenttransitionandthecollisionaldecaybetweentheenergylevelsdestroythefeatureofthespectralnarrowingwhichmaybeconsideredtobetheresultofthemulti channelquantuminterference.
Wei Ji-Lin, Zhang Li-Min, Yu Shu-Qin, Jiang Zhi-Peng
2002, 51 (1): 42-48. doi: 10.7498/aps.51.42
Abstract +
WehavecalculatedtheintensitydistributioninthefocalregionofalaserbeamwithasuperGaussianprofiletruncatedbyacircularaperture.Usingthecalculatedtheoreticalionizationvolumeversusthelaserintensity ,themultipleionizationyieldsofatomsproducedbythetruncatedlaserbeamisstudied .Asanexample,theyieldsofmultiplychargedionsofxenonarecalculat edforfocusedintensitiesintherangeof1 0 1 3 to 1 0 1 6 W cm2 .OscillationsandsuppressionsintheyieldcurvesbecomeobviouslywiththeincreaseofthetruncationsofasupperGaussianbeam .Foralargen,suchasn >2 ,orforstrongtruncations,suchasρa=1 ,ofthesupperGaussianbeam ,theshapeofmultipleionizationyieldsshowslessdependenceonn.Theseoscillationsandsuppressionsinthecalculatedyieldcurvesmaybeusedtoexplaintheexperimentalresultformultiplychargedionsofxenon.
Liang Hai-Chun, Rong Min-Zhi, Zhang Ming-Qiu, Zeng Han-Min
2002, 51 (1): 49-54. doi: 10.7498/aps.51.49
Abstract +
Silvernanoparticleswithdifferentdiametersweresynthesizedbymicroemulsionmethod ,inwhichtheeffectoftolueneorcyclohexaneasanoilphaseontheparticlesizeanditsdistributionwasdetected .Silvernanoparticleswerenear spherical,bothmulticrystalsandtwinswereobserved.Latticedeformationsexistedindifferentdegreesbecausetheinterplanarspacedwasincreased.Thefluorescencespectrafordifferentsizesilvernanoparticlesdispersedinorganicsolventsweremeasured.Therearethreeemissionpeaksforsilvernanoparticles chloroformsystems,whilenofluorescenceemissionwasfoundwhensilvernanoparticlesdispersedintoluene .Thefluorescenceintensityvarieswithparticlesizeofthesilvernanoparticles,whichoriginatesfromAg2 ,Ag3 clustersonthesilverparticlesurfaceproducedbytheinteractionbetweensilverandchloroformunderUVradiation .Thereactivityandthenumberofsurfacereactivecentersvarywithsilverparticlesize,resultinginthedifferentfluorescencephenomena.
Yang Bai-Fang, Miao Jing-Wei, Yang Chao-Wen, Shi Mian-Gong, Tang A-You, Liu Xiao-Dong
2002, 51 (1): 55-62. doi: 10.7498/aps.51.55
Abstract +
TheyieldsofH~-,H ,H_2 ,H_2~ +andH_3 ~+forH_3~ +clusterspassingthroughcarbonfoilshavebeenmeasured .TheresultsshowedthatthechargeexchangeprocessintheinteractionofH3 +ionswithsolidsplaysakeyroleintheformationoftheseproducts.TheclustereffectsandwakeeffectsofH3 +ionsinsolidsarealsodiscussedindetail.
Wang Wei, Huang Lan, Zhang Yu, Li Chang-Min, Zhang Hai-Qian, Gu Yu, Shen Hao-Ying, Chen Tang-Sheng, Hao Li-Ping, Peng Li, Zhao Li-Xin
2002, 51 (1): 63-67. doi: 10.7498/aps.51.63
Abstract +
Singleelectrondeviceshavebeenpreparedbythemolecularself assemblytechniqueandtheirvoltage currentcharacteristicsmeasured .Ontheotherhand,singleelectrondeviceswerestudiedbytheMonteCarlosimulationbasedonasemi classicaltheoryofsingleelectronphenomena.Thesimulatdvoltage currentcurveissimilartothemeasuredone.Thisshowsthattheabovemethodmaybeusedtostudysingleelectrondevices.Furthermore ,thesimulatdresultsindicatethatthevoltage currentcharacteristicofasingleelectrondeviceisdeterminedonlybythesmallquantityofnanoparticlesinthelowvoltageregionthoughtherearealargenumberofnanoparticlesbetweenthetwoelectrodes.
CLASSICAL AREA OF PHENOMENOLOGY
Zhou Chuan-Hong, Wang Lei, Nei Ya, Wang Zhi-Heng
2002, 51 (1): 68-73. doi: 10.7498/aps.51.68
Abstract +
Guided moderesonanceinadielectricgratingresultsfromaredistributionofenergyinpropagatingwaveswhenhigh orderspatialharmonicsarecoupledtotheleakywave guidemodessustainedbythegrating.Inthispaper,wehaveanalyzedtheguided wavemodesinawaveguidewitharigorouscoupled waveapproach .Fromtheanalyzedresults,wehaveestimatedproperlythelocationoftheguided moderesonanceinaweaklymodulateddielectricgrating .Wealsodiscussedtherelationsamongtheguided moderesonance,gratinglayerthickness,substratethickness,andtheincidentangle.Byadoptingadesignforanti refection ,thesymmetricguided moderesonancewithlowsidebandwasachieved .
Chang Mei, Jin Ya-Qiu
2002, 51 (1): 74-83. doi: 10.7498/aps.51.74
Abstract +
TheMuellermatrixsolutionofthevectorradiativetransferequationwithtimedependenceisderivedinthispaper.Itisappliedtothesimulationofpolarimetricbistaticscatteringfromalayerofrandomnon sphericalscatterersnonuniformlyorientedwhenaGaussianplanepulseisincidentuponit.Co polarizedandcrosspolarizedbistaticscatteringarenumericallycalculated .Thepulseechoesarecomparedwiththeincidentpulse.Wedemonstratethefunctionaldependenceofthepulseonthephysicalparametersofarandommedium ,suchasspatialorientationandfractionalvolumeofscatterers,incidenceangleandpolarization ,thelayerdepthetc.
Wan Lin, Liu Su-Mei, Liu San-Qiu
2002, 51 (1): 84-90. doi: 10.7498/aps.51.84
Abstract +
Inthispaper,thesqueezingeffectsofalightfieldintheT CmodelisstudiedbymeansofthequantumtheoryintheCounter Rotating Wave Approximation (C RWA) .Ithasbeenshownthat:thelittleindentationwhichrepresentsthequantum noiseofthesystemappearsintheevolutioncurvesofQundertheC RWA ;thequantumnoisewhichiscausedbyvirtualphotonfieldgraduallybecomesweakwhenωincreases;thequantumnoiseincreaseswhen nincreases;thevirtualphotonprocesscanstrengthenthesqueezingeffectobviously .Besides,thedependenceoftheatom fieldcouplingconstantλandtheatom atomcouplingconstantgonthesqueezingeffectsofthefieldisobservedinourresults.
Xue Ting, Yu Jian, Yang Tian-Xin, Ni Wen-Jun, Li Shi-Chen
2002, 51 (1): 91-98. doi: 10.7498/aps.51.91
Abstract +
Thecharacterizationofall opticalwavelengthconverterbasedonthecascadedsecond ordernonlinearitiesinLiNbO3waveguideshasbeencarriedoutinthisworkinordertofindrulestooptimizethefabricationparametersforstableandhigh efficiencyall opticalwavelengthconvention.Firstly,thecomparisonofnumericalanalysisresultsandthesmall signalanalysisresultsisgivenbasedonthecoupledmodeequation.Secondly,usingthenumericalresults,thedependenceofthefundamentalwavelengthandtheQPMgratingperiodonthebulktemperatureisgivenrespectively.Finally ,therelationshipbetweentheoutputpowerofaconvertedlightandthe 3dBbandwidthoffundamentalwavelength ,bulktemperature ,gratingperiodisanalyzed .
Wei Qing, Wang Qi, Shi Jie-Long, Chen Yuan-Yuan
2002, 51 (1): 99-103. doi: 10.7498/aps.51.99
Abstract +
Inthispaper,theexplicitformulaofJostfunctionpairsinthecaseofpureradiationisderivedbyusingthedressingmethodand,theanalysisoftheinteractionbetweensolitonsandradiationismade.Itisfoundthatinthecourseoftransmission ,theopticalpulse,whoseamplitudedecaysaccordingtothelawofthenegativesquarerootofpowerindexalongthepropagatingdirection ,ultimatelyevolvesintotheformofsoliton likewaveintheabsenceofradiation .Itisrevealedthatthefactorγplaysanimportantroleinthespectrumpropertiesfortheoutputoftheopticalpulse .Thedynamicalbehaviouroftheevolutionofsoliton likewavesduringtheinteractionofsolitonsandradiationisalsoanalyzed.
Wu Guang-Ming, Lu Hong-Yan, Wang Yu, Shen Jun, Zhou Bin, Zhang Qin-Yuan, Deng Zhong-Sheng
2002, 51 (1): 104-110. doi: 10.7498/aps.51.104
Abstract +
Scratch resistantsilicaaerogelfilmswitha 77%porosityand 1 . 1 2refractiveindexatambientpressureisreportedusingtheexchangeofsolventandmodificationof—CH3 group.Thesilicafilmswerepreparedinasol gelprocessbyadip coatingmethod ,andthenwerepostannealedinairandamixedgasatmosphere.Thefilmswerecharacterizedwithtransmissionelectronmicroscope,scanningelectronmicroscope,FourierTransforminfraredspectroscope,anellipsometer,andtheabrasiontest,respectively.Withthepostannealing,thefrequencyshiftofFTIRabsorptionω4(TO3 )peakofthefilmstoalowerwavenumberresultsfromadecreaseintheaverageSi—O—Sibridgingangle.Anincreaseinthefullwidthathalf maximum (FWHM)oftheω4peakisascribedtoawidedistributionofthebridginganglebecauseoftheformationofstrainedSi—O—Sibondscausedbythepostannealing.Theabrasionandadhesiontestsindicatethatthemixedgastreatmentnoticeablystrengthensthesilicanetwork .TheincreaseinstrengthisattributedtomoreSi—O—Sibondcross linkagesbetweensilicaparticlesformedbythemixedgastreatment.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
Zhang Shi-Bin, Kong Guang-Lin, Xu Yan-Yue, Wang Yong-Qian, Diao Hong-Wei, Liao Xian-Bo
2002, 51 (1): 111-114. doi: 10.7498/aps.51.111
Abstract +
Transientphotoconductivityanditslight inducedchangewereinvestigatedbyusingaModel440 0boxcaraveragerandsignalprocessorforlightlyboron dopeda Si∶Hfilms.Thetransientphotoconductivitiesofthesampleweremeasuredatanannealedstateandlight soakedstates.Thetransientdecayprocessofthephotoconductivitycanbefittedfairlywellbyasecond orderexponentialdecayfunction ,whichindicatesthatthedecayprocessisrelatedwithtwodifferenttraps.Itisnoteworthythatthephotoconductivityofthefilmincreasesafterlight soaking.ThismaybeduetothedeactivityoftheboronacceptorB-4,andthussomeoftheboronatomscannolongeractasacceptorsanddrivesEFtoshiftsupward .Consequently,thenumberofeffectiverecombinationcentersmaybereducedandsothephotoconductivityincreases.
Li Xiao-Na, Nie Dong, Dong Chuang, Ma Teng-Cai, Jin Xing, Zhang Zhe
2002, 51 (1): 115-124. doi: 10.7498/aps.51.115
Abstract +
Iron silicidefilmshavebeensynthesizedbymetalvaporvacuumarc (MEVVA)ionimplantationofironinto (1 1 1 )and (1 0 0 )orientedsiliconwafers.Thestructureevolutionwascharacterizedusingtransmissionelectronmicroscopy (TEM)andhighresolutionelectronmicroscopy (HREM) .TheβFeSi2filmsandburiedlayerswithdifferentdepthandthicknesswereobtainedbyadjustingtheimplantationenergyanddose .Theformationofα,β,γandCsCl FeSi2 phaseshavebeenobserved .ThephasetransitionorderisγFeSi2→βFeSi2→αFeSi2,CsClFeSi2→βFeSi2→αFeSi2 or βFeSi2→αFeSi2.Anamorphouslayerwasformedat60kVand 4× 1 0 1 7ions cm2 ,thephasetransitionorderisamorphous→β FeSi2 →α FeSi2 .Themorphologyandpositionofthesilicidefilmschangewiththeannealingtemperature.Thesilicidegrainsgrowwithincreasingannealingtemperaturewithfurtherincreaseoftemperature ,thecontinuoussilicidelayersshrinkintoisolatedislandsandtheinterfaceβ FeSi2 Sibe comesrougher.Inthispaper,thecomplicatedorientationrelationshipsexistingbetweenβ FeSi2 andSiwerealsoinvestigated
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
Yao Ming-Zhen, Liang Ling, Gu Mu, Duan Yong, Ma Xiao-Hui
2002, 51 (1): 125-128. doi: 10.7498/aps.51.125
Abstract +
ThispaperpresentsastudyonelectronicstructuresofdefectsassociatedwithoxygenvacancyVOandleadvacancyVPbinleadtungstatecrystals (PbWO4) ,bytherelativisticself consistentdiscretevariationalembeddedclustermethod .Furthermore,theexcitationenergyisalsocalculated.WefoundthatWO3 +VOcouldbetheabsorptioncenterat3 50nmand 42 0nm ,andtheexistenceofVPbcandiminishthebandgapofWO42 -.
Meng Ji-Bao, Chen Zhao-Jia, Luo Jian-Lin, Bai Hai-Yang, Wang Wei-Hua, Zheng Ping, Zhang Jie, Shu Shao-Kui, Jin Duo, Wang Yu-Peng
2002, 51 (1): 129-133. doi: 10.7498/aps.51.129
Abstract +
Inthispaper,theexperimentalresultsofthelow temperatureresistancebetween 0.1Kto 2 50Kandspecificheatbetween5Kto 70KofheavyfermioncompoundsCeCu6 xNix(x =0.0 ,0.0 5,0.1 ,0.15,0.2 )arereported .ThedopingeffectoftheNicontentonthelow temperaturepropertiesofCeCu6 isstudied .Thetemperaturesofresistancemaximuasofthesamplesreducedramaticallywiththeincreaseofthedopingcontentx.ThisindicatestheenhancementofmagneticmomentofminorCeionsthatareneighboringNiatomandthedecreaseofthecoherentscatteringbetweenthewholeCeionlatticeandtheconductionelectrons.Thelow temperatureelectronicspecificheatcoefficientγ(CE T ,whereCEistheelectronicspecificheat)isnearlyaconstantatlowtemperatures,butitapparentlyincreasesbelow 8Kduetotheincreaseofitseffectivemass.However,thetem peratureatwhichγbeginstoincreaseisnotsensitivetothecontentofNi,indicatingthatthestatusofmostceriumionsarenotaffected.
Zhang Xi-Juan, Li Guang-Qi, Sun Xin
2002, 51 (1): 134-137. doi: 10.7498/aps.51.134
Abstract +
Howtoexcitethebiexctionsinapolymerisanessentialsubject,sincethebiexcitonpossessesaneffectofphoto inducedpolarizationreversion.Thispaperproposesanewchanneltoproducethebiexcitonthroughtwo electronexcitation.Therelaxationprocessesofbothlatticedistortionandelectronicstatesaresimulatedbystudyingitsdynamics,andtherelaxationtimeofbiexcitonformationandpolarizationreversionisdetermined .
Xiao Xi-Feng, Kang Jun-Yong
2002, 51 (1): 138-142. doi: 10.7498/aps.51.138
Abstract +
VoltagetransientsduetothethermalelectroncaptureandemissionofDXcentersinn typeSn dopedAl0 . 2 6 Ga0 .74Aswere measuredbytheconstantcapacitancetechniqueandtransformedbyLaplacedefectspectroscopy (LDS) .Byanalyzingthevariationsofdiscreteemissionrateswithdifferentcaptureperiods,correspondingrelationsbetweendiscretecaptureandemissionratesandcapturecoefficientsweredetermined .ThefinestructuresofelectroncapturebarriersoftheSn relatedDXcenterswereobtainedbylinearfittingthedataoftemperature dependencesofthecapturecoefficients.TheresultscalcuatedbyusingthefirstprinciplepseudopotentialmethodshowthatthefinestructuresofthecapturebarriersmainlycontributetoAl GaatdifferentlocalconfigurationsnearSnatomsduetothealloyrandomeffect.
Xu Hui, Song Wei-Pu, Li Xin-Mei
2002, 51 (1): 143-147. doi: 10.7498/aps.51.143
Abstract +
Aconductancemodelofelectronictunnelingtransferissetup,andanewD .Cconductanceformulainone dimensionaldisorderedsystemisderived .BycalculatingtheD .Cconductivity,therelationshipamongtheelectricfield、temperatureandconductivityisanalyzed ,andtheeffectofdisordereddegreeontheD .Cconductanceisdiscussed .Theresultshowsthattheconductivityofadisorderedsystemdecreaseswiththeincreaseofdisordereddegree.Whentheelectricfieldisweak ,itsconductivityishighandhasaseriesofpeakvalues.Hewever,whentheelectricfieldisstrong,itsconductivityisweak.Inthelow temperatureregion,thedisorderedsystemshowsacharacteristicofnegativedifferentialdependenceofresistanceandtemperature.Onthecontrary,itsconductivitydecreaseswiththeriseoftemperatureinthehigh temperatureregion.Thisresultisingoodagreementwiththeexperiments.
Yang Lin-An, Zhang Yi-Men, Gong Ren-Xi, Zhang Yu-Ming
2002, 51 (1): 148-152. doi: 10.7498/aps.51.148
Abstract +
Alarge signalanalyticalmodelwithtemperatureconsideredfor4H SiCradiofrequencypowerMESFETI Vcharacteristicsisproposedbasedonthetheoryofsaturatedcarriervelocity,bymeansofwhichtheself heatingeffectistakenintoaccountsoastoanalyzethetemperatureperformanceofSiCpowerMESFET .Theheattransportbetweenthechannelandthesubstrateismodeledwithnon constanttemperatureT0 atthebottomof4H SiCsubstrateinordertofittherealactionsofdevices.Agoodagree mentbetweensimulationandmeasurementisobtained.
He Guo-Gang, Wang Xiao-Sheng, She Wei-Long, Tao Meng-Xian, Lin Li-Peng
2002, 51 (1): 153-158. doi: 10.7498/aps.51.153
Abstract +
Wehaveobservedthataweaklightbeamwillexperienceadefocusing contractprocessbeforeitcomestosteadystatewhenpassingthroughaCu:KNSBNcrystalwithatransientspatialelectricfield.Thisprocessbecamefastbyincreasingintensityofthelightbeam .Webelievethatthedefocusing contractprocessresultsfrombotheffectsofthetransientelectricfieldinthecrystalsandthephotovoltaicandrefocusingfieldsgeneratedbythebeamitself.
Long Chao-Yun, Liu Bo, Wang Xin-Fu
2002, 51 (1): 159-162. doi: 10.7498/aps.51.159
Abstract +
Thequantumwavefunctionandthecorrespondingenergylevelsofthedissipativemesoscopiccapacitancecouplingcircuitsareobtainedbyusingunitaryandlineartransformations.Thequantumfluctuationofchargeandcurrentinanarbitraryeigenstateofthesystemhavebeenalsogiven.Theresultsshowthatthefluctuationofchargeandcurrentdependsonnotonlytheeigenstatebutalsotheelectronicdeviceparameters.
Liu Hong-Xia, Zheng Xue-Feng, Hao Yao
2002, 51 (1): 163-166. doi: 10.7498/aps.51.163
Abstract +
Thispaperpresentsanexperimentalmethodformeasuringthedensityoftrappingcharges.Thismethodisbasedonthedy namicequilibriumequationfortheprocessoftrappedcharges.WecanobtainthedensityandthelocationoftrappingchargesbymeasuringthehighfrequencyC VcurveofMOScapacitancebeforeandafterstress,andthechangeofgatevoltageunderconstantcurrentstress.Theanalyticalexpressionofthedensityoftrappingchargesisproposed .Themethodandtheresultsofparametersextractionarealsopresented .Experimentalresultsshowthatthismethodisconvenientandprecise .
Jiang Wen-Hong, Luo Si-Wei, ZhongcunQingjiu
2002, 51 (1): 167-170. doi: 10.7498/aps.51.167
Abstract +
Inmeasurementsoftimedecayinaperpendiculardouble layeredmedium ,alargeoutputdecaywasobservedwhenaregularsingle poleheadwasusedforbothwritingandreading .Investigationsofthisphenomenonrevealedthatthedemagnetizationofthemediumwascausedbytheinstabilityofthedomainwallofthemainpolefilmandalsobytheconcentrationofstrayfieldsbythemainpoleduringthereadingprocess.Severalcountermeasureswereproposed .
Wang Yuan-Xu, Zhong Wei-Lie, Wang Chun-Lei, Zhang Pei-Lin
2002, 51 (1): 171-173. doi: 10.7498/aps.51.171
Abstract +
InordertoobtainthefinestructureoftetragonalferroelectricPbFe0.5Nb0.5O3 ,wecalculateditstotalenergybyfull potentiallinearizedaugmentedplanewavemethod .TheequilibriumconfigurationofB sitecations(FeandNb)wasdetermined .ThedisplacementofFeionsalong [0 0 1 ]directioninthefinestructureis0 .0 2 2nmandthatofNbionsis0 .0020nm .Theferroelec tricinstabilityresultsmainlyfromthedisplacementofFeions.
Gao Yu-Lin, Lu Yi-Jun, Zheng Jian-Sheng, Chai Zhi-Gang, Sang Hai-Yu, Zeng Xue-Ran
2002, 51 (1): 174-177. doi: 10.7498/aps.51.174
Abstract +
Thetime resolvedphotoluminescence (TRPL)spectraoforderedGa0 .5In0 . 5Palloysgrownbymetalorganicvaporphaseepitaxywereinvestigated .Theleast squarefittingoftheluminescencedecayspectrashowsthatthereexisttwoexponentialprocesses:forthequickprocessthelifetimeτ1 isabout1 2 8ps— 2 50psand 1 86ps— 546psatroomtemperatureand77K ,respectively;andfortheslowprocessthelifetimeτ2 is,about3 0 8ps— 1 83 2ps,atroomtemperatureandat77K ,aslongasnanosecondandevenmorethan 2 8ns.Theshortlifetimeprocessbelongstotherecombinationofcarriersintheordereddomains,correspondingtothehigh energypeakinthePLspectra.Thelonglifetimeprocesscorrespondstothelow energypeakinthePLspectra.Thestrongexcitationintensitydependenceofτ2 atafixedenergyindicatesthatthelonglifetimeprocesscouldnotbeexplainedintermsofdonor acceptorpair(DAP) .Weattributetheemissiontotherecombinationbetweenthespatiallyseparatedcentersoftheelectronsinordereddomainsandtheholesindisorderedregions.TheTRPLspectraat77Kexhibitablue shiftwithtimedelay ,indicatingthatthecarrierstransferfromdisorderedregionstoordereddomains.
Yang He-Qing, Wang Xuan, zhang Bang-Lao, Li Yong-Fang, Zhang Liang-Ying, Yao Xi
2002, 51 (1): 178-182. doi: 10.7498/aps.51.178
Abstract +
TheGeO2 SiO2 gel glasseswerepreparedbythesol gelmethodwithtetraethoxysilane (Si(OC2 H5) 4)and 3 trichloroger maniumpropanoicaci (Cl3 GeCH2 CH2 COOH)asstartingmaterials.Thegel glassesshowastrongroom temperaturephotoluminescencewithpeaksat575and 62 4nmundertheexcitationofthe 53 2nmlineofaNd∶YAGlaser.Thephotoluminescence spectraarecausedbyGeO2 nanoparticlesembeddedingel glasses.TheGeO2 SiO2 gel glassesarecharacterizedbytheopticalabsorption,X raydiffraction (XRD)andtransmissionelectionmecroscopy.ThesizeofGeO2 nanoparticlesembeddedingelglassesbecomeslargerastheGeO2 contentincreases,andthustheopticalabsorptionedgeofthegel glassshiftstothelower energyside .TheGeO2 nanoparticlestructuresarefoundtobeamorphousGeO2 inthegel glassesbytheXRDandtheelectrondiffractionpattern .
Liu Fa-Min, Wang Tian-Min, Zhang Li-De
2002, 51 (1): 183-186. doi: 10.7498/aps.51.183
Abstract +
NanocrystallineGaSbParticlesembeddedinSiO2 filmsweregrownbyradiofrequencymagnetronco sputtering .ThetransmissionabsorptionofthecompositefilmwasrecordedwithCary 5Espectrophotometeratroomtemperature.Thetwo photonopticalnonlinearitiesoftheGaSb SiO2 compositethinfilmsat63 2 .8nmweremeasuredbyZ scanmethod,andtheresultsare:twophotonabsorptioncoefficientβ≈ 0 . 0 82m W ,nonlinearrefractiveindexγ≈ 3 .76× 1 0 -9m2 Wandthenonlinearsusceptibilityχ(3 )≈ 7.84× 1 0 -9esu .
Cui Da-Fu, Wang Huan-Hua, Dao Shou-Yu, Zhou Yue-Liang, ChenZheng Hao, Yang Guo-Zheng, Liu Feng-Qin, K .Ibrahim, Qian Hai-Jie
2002, 51 (1): 187-191. doi: 10.7498/aps.51.187
Abstract +
OpticallytransparentSb dopedSrTiO3 (SrTi1-xSbxO3 )thinfilmswithatransmittancehigherthan 90 %invisibleregion havebeengrownonSrTiO3 (0 0 1 )substratesbypulsedlaserdepositionmethodusinganXeCllaserunderoxygenpartialpressureof2 0Pa.ThethinfilmwithSbdopingconcentrationofx=0 .0 5showsmetallic likeconductivitywitharesistivityρ~ 6.99×1 0 -3 Ω·cmatroomtemperature.XPSandsynchrotronradiationphotoelectronspectroscopy (SR PES)measurementfromtheSrTi0 . 95Sb0 .0 5O3 thinfilmrevealsthattheshallowanddeepimpuritydonorlevelswithinthebandgapoftheparentcompoundSrTiO3 areinducedbytheSbdoping.ThedelocalizedelectronswithintheshallowlevelsneartheFermilevelcanbeexcitedtotheconductionbandasfreecarriersforelectricalconductionbythermalionization.Thewidebandgap ,smalltransitionprobabilityandweakabsorptionduetothelowdensityofstatesintheimpuritylevelsresultintheopticaltransparencyofthefilm .
Yao Jiang-Hong, Chen Ya-Hui, Xu Jing-Jun, Zhang Guang-Yin, Zhu Sheng-Xing
2002, 51 (1): 192-196. doi: 10.7498/aps.51.192
Abstract +
Thedomainreversalcharacteristicsofnear stoichiometricLiNbO3 singlecrystals,whichwerepreparedbytheCzochralskimethodwithK2 Ofluxandthevaportransportequilibration,wereinvestigated.Theresultsshowthattheswitchfieldfor1 80°ferroelectricdomainreversalinthenear stoichiomentLiNbO3 crystaldecreaseswith [Li] [Nb]ratio.Wesuccessfullyachieved1 80°domainreversalinthenear stoichiometricLiNbO3 samplesof1 . 0mmthicknessbyusinga4. 0kV mmswitchfield .ApreliminaryexplanationforexperimentalresultsisgivenbasedontheLi sitevacancypointdefectmodel.