Acta Physica Sinica
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Acta Physica Sinica  
  Acta Physica Sinica--2002, 51 (12)   Published: 15 December 2002
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CLASSICAL AREA OF PHENOMENOLOGY

Three stage polarization mode dispersion compensator capable of compensating second order polarization mode dispersion

Zheng Yuan, Yu Li, Yang Bo-Jun, Zhang Xiao-Guang
Acta Physica Sinica. 2002, 51 (12): 2745 doi: 10.7498/aps.51.2745
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The impacts of polarization\|dependent dispersion on systems are investigated brefly, based on which we propose a threestage higherorder polarization mode dispersion(PMD) compensation scheme. Theoretical analysis shows that it is capable of compensating polarization\|dependent dispersion and principal states of polarization rotation rate at the same time. The two possible operating points of this compensator are proposed. Numerical results show that the maximum tolerable PMD value after threestage compensation has been improved by 17% per bitslot than that using twostage compensator.

Output characteristics of tunable fiber ring-laser:modeling and experimentation

Dong Xin-Yong, Zhao Chun-Liu, Guan Bai-Ou, Tan Hua-Yao, Yuan Shu-Zhong, Kai Gui-Yun, Dong Xiao-Yi
Acta Physica Sinica. 2002, 51 (12): 2750 doi: 10.7498/aps.51.2750
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Output characteristics of a tunable fiber ring laser are studied both by theoretical modeling and by experimentation. Dependencies of laser output power on lasing wavelength, pump power, erbiumdoped fiber (EDF) length, output coupling ratio, and intracavity loss are demonstrated by using a simple theoretical model. It is shown that a wide tunable range over 130nm (i.e.1500—1630nm) can be obtained through parameter optimization. As a result, the laser with a tunable range up to 100nm, high output power, and high signaltonoise ratio in most of the tunable range has been achieved in experimentation. The experimental data are in good agreement with the theoretical modeling results.

Study on passive Q switched Nd∶YVO—4 laser with GaAs asa passive Q switched component and output coupler

Liu Qiang, Gong Ma-Li, Yan Ping, Jia Wei-Fu, Cui Rui-Zhen, Wang Dong-Sheng
Acta Physica Sinica. 2002, 51 (12): 2756 doi: 10.7498/aps.51.2756
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Passive Q switched operation of a laser diodepumped laser is studied with a saturable absorber GaAs as a passive Q switched component and F-P output coupler. The Q switched pulse duration is 47ns, pulse repetition rate is 1183 kHz, pulse average power is 430mW, beam quality M 2 is equal to 1 13 and the laser threshold of passive Q switching is 1700mW. We performed numerical calculations of coupled wave equations for the case of GaAs playing the role as mentioned above, discussed the passive Q switched mechanism and the dependence of pulse duration, pulse repetition rate and average power on the pumping rate and laser cavity length, which was in good agreement with the experimental results. A brief and effective technique is provided for compact Q switched solidstate laser having multiple functions.

The dynamic conversion from self-defocusing to self-focusing and the phase conjugate bright spatial soliton*

Liu Si-Min, Wang Da-Yun, Zhao Hong-E, Li Zhu-Bin, Guo Ru, Lu Yi, Huang Chun-Fu, Gao Yuan-Mei
Acta Physica Sinica. 2002, 51 (12): 2761 doi: 10.7498/aps.51.2761
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We have further studied experimentally and theoretically the process of conversion from self-defocusing to self-focusing in LiNbO—3:Fe crystals, which was reported in Acta Phys.Sin.[STHZ]50[STBZ] 483. Based on our experimental result, we have proposed a new type of theoretical model of phase conjugate resonant cavity, analyzed the role of the cavity in the process of conversion from self-defocusing to selffocusing. We have also proposed a new type of bright spatial soliton, i.e.,the phase conjugate bright spatial soliton, and indicated that the bright spatial soliton is a mode in the phase conjugate resonate cavity.

The influence of the ratio of seed to pump energy on Brillouin amplification*

Ding Ying-Chun, Lv Zhi-Wei, He Wei-Ming
Acta Physica Sinica. 2002, 51 (12): 2767 doi: 10.7498/aps.51.2767
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Brillouin amplifier was numerically simulated by using the theoretic model of transient stimulated Brillouin scattering. Wehave oblained the depleted pump energy extract efficiency, Stokes seed amplification factor, seed beam pulse\|width compression ratio and pump beam pulse\|width compression ratio versus the ratio of seed to pump energy. Experiment was done so as to verify the theory. The theoretical calculation was in good agreement with experimental results.

Modulation on dynamical evolution of Gaussian beam in an unbiased serial photorefractive crystal circuit*

Hao Zhong-Hua, Liu Jin-Song
Acta Physica Sinica. 2002, 51 (12): 2772 doi: 10.7498/aps.51.2772
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Based on the theory of one\|dimensional separate spatial soliton pair formed in an unbiased serial photorefractive(PR) crystal circuit consis-ting of two PR crystals connected by electrodes, the mutual dependences of the two solitons are investigated. When a dark soliton beam and a Gaussian beam are incident on the two PR crystals, respectively, the effects of changing the peak intensity of the dark soliton on the propagating property of the Gaussian beam are discussed by numerical calculations. The result shows that the dynamical evolution of Gaussian beam in one crystal can be modulated by changing the intensity of the dark soliton in the other in the circuit. By this way one can determine whether the Gaussian beam could evolve into a solitary wave or ont.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

Surface energy of the biaxial nematic liquid crystal

Liu Hong
Acta Physica Sinica. 2002, 51 (12): 2786 doi: 10.7498/aps.51.2786
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In this paper, two forms of surface energy of the biaxial nematic liquid crystal are derived. One is related to the deviation of surface directors with respect to the easy axes0,0 and0in the surface. The other is related to the surface order parameter matrix Q. The relations between the two forms are derived. In the former one, four independent coefficients are involved while in the latter one, only two independent coefficients are involved. In order to inspect the physical meaning of these coefficients, a simple model of molecular interaction between liquid crystal and boundary plate is proposed. In the model, the biaxial orientation of molecules along0and 0 is assumed to arise from two perpendicular mean fields along 0,0competing with each other. In three geometric features of Freedericksz transition where and rotate around 0, [WTHX][AKb^][WTBZ] and [WTHX][AKc^D][WTBZ] around [WTHX][AKa^D][WTBZ]0,[WTHX][AKc^D][WTBZ] and [WTHX][AKa^D][WTBZ] around [WTHX][AKb^][WTBZ]0 respectively, possible experimental measurements of surface anchoring coefficients [WTBX]Wa,Wb[WTBZ] and [WTBX]Wc[WTBZ] involved in the distortions are explored.

Influence of metal ions on the morphology and phase composition of titanium dioxide in TiO-2 muscovite nanocomposites*

Song Gong-Bao, Liu Fu-Sheng, Peng Tong-Jiang, Liang Jing-Kui, Rao Guang-Hui
Acta Physica Sinica. 2002, 51 (12): 2793 doi: 10.7498/aps.51.2793
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SomesamplesofTiO2 muscovitenanocompositeundopedanddopedwithmetalionswerepreparedbychemicalliquidphasa deposition .ThemorphologyandphasecompositionofTiO2 filmwerestudiedbyscanningelectronmicroscopyandx raydiffraction.TheresultsshowedthatthegrainsizeoftheTiO2 particlesrangesfrom 1 5to 50nm .Besidescirculargrains,thereweresomeeuhedralrutilegrainsinthesamplesdopedwithZn2 +andMn2 +ions.RutileandanatasewerefoundintheTiO2 film .TheinfluenceofdopedmetalionsonthephasecompositionofTiO2 filmwasdeterminedbyradius,chargeandligandofmetalions

Moleculardynamicssimulationsoflow energyPtclusterdeposition

Ye Zi-Yan, Zhang Qing-Yu
Acta Physica Sinica. 2002, 51 (12): 2798 doi: 10.7498/aps.51.2798
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Moleculardynamicssimulationshavebeenappliedtotheinvestigationofthedepositionoflow energyPt3 8,Pt1 41 ,andPt2 6 6clustersonPt(0 0 1 )surface .Theevolutionprocessofclusterdepositionwithatomicaveragekineticenergies (Ea)of0 .1 ,1 .0and 1 0eVandtheeffectsonthesubstratesurfacemorphologyhavebeenanalyzed.SimulationresultsshowthatEaisanimportantparametertodescribebehavioursoftheclustes.ClusterswithlowEacannotdamagethesurfacelatticeseriouslyandtheclusterscanbeconsideredasadepositioncluster.ThepowerofclusterdamagingsurfacelatticeincreaseswiththeincreaseofEa.WhenEa=1 0eV ,theclusterscanimplantintothesubstrate.TheeffectsoflowenergeticclustersonsubstratesurfacemorphologyarealsodeterminedbyEa.Theeffectsofclusterswithmoreatoms,however,arestrongerthanthatwithfeweratoms.Themecha nismsoftheinteractionsbetweenlow energyclustersandsubstratesurfacearealsodiscussedinthispaper
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

First principlesstudyonα SiC (1 0 1 0 )surfacestructure

Xie Chang-Kun, Xu Peng-Shou, Xu Fa-Qiang, Pan Hai-Bin
Acta Physica Sinica. 2002, 51 (12): 2804 doi: 10.7498/aps.51.2804
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Wepresentatheoreticalcalculationontheatomicandelectronicstructureofα SiCanditsnon polar(1 0 1 0 )surfaceusingthefull potential linear augmented plane wave (FPLAPW)approach.Thecalculatedlatticeconstantsandbulkmodulusofα SiCcrystalareinexcellentagreementwithexperimentaldata .Theatomicandelectronicstructureofα SiC (1 0 1 0 )surfacehavebeencalculatedbyemployingslabandsupercellmodels.Itisfoundthatthesurfaceischaracterizedbyatop layerbond length contractingrotationrelaxationinwhichbothSiandCatomshavethetendencytomovedowntowardthebulktoformplanarconfigu rationwiththeirneighboursandSimovesfurthertowardthebulkthanCdoes.Furthermore ,surfacerelaxationinducesthetransformationfromsemi metallictosemiconductingcharacterization

Theeffectofdoped Znonthelow temperaturepropertiesofheavyelectroncompoundsCeCu6 -xZnx

Meng Ji-Bao, Chen Zhao-Jia, Luo Jian-Lin, Bai Hai-Yang, Wang Nan-Lin, Wang Yu-Peng
Acta Physica Sinica. 2002, 51 (12): 2812 doi: 10.7498/aps.51.2812
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Wereporttheparticularsamplepreparationmethodandtheexperimentalresultsofthelow temperatureresistanceandspe cificheatofheavyelectronmetalsCeCu6 -xZnx(x=0 .0 5,0 .1 0 ,0 .1 5,0 .2 0 ,0 . 3 0 ) .ThephysicaloriginfortheeffectoftheZncontentonthelow temperaturepropertiesofCeCu6 -xZnxarestudied.WefindthatboththecoefficientcofKondoscatteringtermandtheTmaxcorrespondingtothemaximalresistancedecreaseswithincreasingZncontent.WhiletheDebyetemperatureofCeCu6 -xZnxslightlygoupwithincreasingZncontent.

Solitonpropertiesoflighttransportationinioniccrystalsgeneratedbynonlineareffects

Niu Jia-Sheng, Ma Ben-Kun
Acta Physica Sinica. 2002, 51 (12): 2818 doi: 10.7498/aps.51.2818
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Inthispaper,wediscusstheoreticallythesolitonpropertiesoflightpulsetransportationoriginatingfromstrongnonlinearin teractionsbetweenionsinunitcellsofioniccrystals,andanalyzeindetailthebrightsolitonsanddarksolitonswhenthenonlinearcoefficientgispositiveandnegative.Itisfoundthatwhetherthenonlinearcoefficientgispositiveornegative,thebrightsolitonscanbeobtainedoverthelongitudinalopticalphononfrequencyωLO.Forg >0 ,darksolitonscanbeformedunderthetransverseopticalphononfrequencyωTO,whatshouldbepayedattentiontoisthatbetweenωTOandωLO,thelightpulsecanformadvanceddarksolitons.Forg <0 ,thereisaswitchingareafromtheadvancedbightsolitontoretardeddarksolitonnearbutbelowωTO.Wealsodiscusstheeffectsofhighernonlineardispersionsonthesolitons.

Thermoelectricpropertiesofn typeBayNixCo4-xSb1 2

Tang Xin-feng, Chen Li-Dong, T Goto, T Hiral, Yuan Run-Zhang
Acta Physica Sinica. 2002, 51 (12): 2823 doi: 10.7498/aps.51.2823
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EffectsofBafillingfractionandNicontentonthethermoelectricpropertiesofn typeBayNixCo4-xSb1 2 (x =0— 0.1 ,y= 0— 0.4)wereinvestigated .ThermalconductivitydecreasedwithincreasingBafillingfractionandtemperature.Whenywasfixedat0 .3 ,thethermalconductivitydecreasedwithincreasingNicontent,andreachedaminimumvalueataboutx=0 . 0 5.LatticethermalconductivitydecreasedwithincreasingNicontent,monotonically (y≤ 0 .1 ) .Electronconcentrationandelectri calconductivityincreasedwithincreasingBafillingfractionandNicontent.SeebeckcoefficientdecreasedwithincreasingBafill ingfractionandNicontent.ThemaximumZTvalueof1 .2wasobtainedatabout90 0Kforn typeBa0 . 3 Ni0 . 0 5Co3 . 95Sb1 2

Stabilitydiagramsforsingle electrontransistors

Wu Fan, Wang Tai-Hong
Acta Physica Sinica. 2002, 51 (12): 2829 doi: 10.7498/aps.51.2829
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Basedonanequivalentcircuitforsingle electrontransistors,theelectrostaticenergyonthechargesisdeduced .ThetransistorcanbeeitheratCoulombblockadeorconductingundervariousgatevoltagesandbiasvoltagesalongthesingle electrontransistor.Itsstabilitydiagramsaregivenanddiscussed.

Aunifiedmodelfor 1 fnoiseand 1 f2 noiseduetoelectromigrationinmetalfilm

Du Lei, Zhuang Yi-Qi, Xue Li-Jun
Acta Physica Sinica. 2002, 51 (12): 2836 doi: 10.7498/aps.51.2836
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Basedontheconceptoffreevolumeingrainboundary ,aunifiedmodelfor1 fnoiseand 1 f2 noiseinmetalfilmispro posed.Itisshownfromthemodelthatthenoiseinthemetalfilmwithperfectpolycrystallinestructureappearstobe 1 ftype,while 1 f2 componentisintroducedwhenthefilmissubjectedtoacertaineletromigrationstressandthevoidsthusinduced.Itisobservedintheelectromigrationstresstestconductedbypresentauthorsthatγis1 0orsoforthemeasured 1 fγ noiseinthemetalfilmintheinitialstagesofthetest,butγabruptlyincreasedtoover1 6assoonasthevoidsareformed .Thisagreeswiththepredictionofthedevelopedmodel.

EffectofthedepositiontemperatureonthesuperconductivityofMgB2 thinfilms

Wang Shu-Fang, Zhu Ya-Bin, Zhang Qing, Zhou Yue-Liang, Chen Zheng-Hao, Lu Hui-Bin, Yang Gul-Zheng
Acta Physica Sinica. 2002, 51 (12): 2842 doi: 10.7498/aps.51.2842
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SuperconductingMgB2 thinfilmswerefabricatedbyatwo stepmethod.Boronthinfilmsweredepositedbypulsedlaser depositionfollowedbyanex situannealingprocess.Scanningelectronmicroscopy ,x raydiffraction ,resistanceandmagneticmeasurementswerecarriedouttostudytheeffectofthedepositiontemperatureofBfilmsonthesuperconductivityofMgB2 thinfilms.TheTonsetc andJcoftheMgB2 thinfilmsincreasewiththedecreaseofthedepositiontemperature.TheMgB2 thinfilmspre paredat3 0 0℃appeartohaveaTonsetc of3 9 5KandaJcof1 . 3× 1 0 7A·cm-2 at1 5Kinzerofield .

ThemagnetocrystallineanisotropyofEr3 Ga5O1 2underhighmagneticfield

Wang Wei, Zhang Xi-Juan, Yang Cui-Hong, Cheng Hai-Ying
Acta Physica Sinica. 2002, 51 (12): 2846 doi: 10.7498/aps.51.2846
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Magnetizationiscalculatedat4 2Kunderahighmagneticfieldusingquantumtheorywhenthemagneticfieldisapplied parallelto[0 0 1 ],[1 0 0 ],[1 1 0 ]and [1 1 1 ]directions.Astronganisotropyofmagnetizationisobserved .Atlowtemperature,themagnetizationisalinearfunctionofthemagneticfieldappliedwhenthefieldisweak

Theinfluenceof(Ni0 81 Fe0 1 9)1 -xCrxseedlayerontheexchangebiasofNiFe FeMnbilayers

Teng Jiao, Cai Jian-Wang, Xiong Xiao-Tao, Lai Wu-Yan, Zhu Feng-Wu
Acta Physica Sinica. 2002, 51 (12): 2849 doi: 10.7498/aps.51.2849
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Li Ming-Hua, Yu Guang-Hua, He Ge, Zhu Feng-Wu, Lai Wu-Yan
Acta Physica Sinica. 2002, 51 (12): 2854 doi: 10.7498/aps.51.2854
Full Text: [PDF 156 KB] Download:(771)
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Xiao San-Shui, Shen Lin-Fang, He Sai-Ling
Acta Physica Sinica. 2002, 51 (12): 2858 doi: 10.7498/aps.51.2858
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Zhuang Fei, Wu Liang, He Sai-Ling
Acta Physica Sinica. 2002, 51 (12): 2865 doi: 10.7498/aps.51.2865
Full Text: [PDF 234 KB] Download:(809)
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Yang Xiu-Jian, Shi Chao-Shu, Xu Xiao-Ling
Acta Physica Sinica. 2002, 51 (12): 2871 doi: 10.7498/aps.51.2871
Full Text: [PDF 169 KB] Download:(714)
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Peng Hong-Shang, Song Hong-Wei, Chen Biao-Jiu, Wang Ji-Wei, Lv Shao-Zhe, Kong Xiang-Gui, Li Dian-Chao
Acta Physica Sinica. 2002, 51 (12): 2875 doi: 10.7498/aps.51.2875
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Zhang Chun-Xiang, Tang Qiang, Luo Da-Ling
Acta Physica Sinica. 2002, 51 (12): 2881 doi: 10.7498/aps.51.2881
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Zhao Hui, Dong Bao-Zhong, Guo Mei-Fang, Wang Liang-Shi, Qiao Jin-Liang
Acta Physica Sinica. 2002, 51 (12): 2887 doi: 10.7498/aps.51.2887
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INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

Wang Yin-Shu, Sun Ping, Ding Shuo, Luo Xu-Hui, Li Na, Wang Ruo-Zhen
Acta Physica Sinica. 2002, 51 (12): 2892 doi: 10.7498/aps.51.2892
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Dong Zheng-Gao, Shen Ming-Rong, Xu Run, Gan Zhao-Qiang, Ge Shui-Bing
Acta Physica Sinica. 2002, 51 (12): 2896 doi: 10.7498/aps.51.2896
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Zhang Hong-Rui, Liang Er-Jun, Ding Pei, Du Zhu-Liang, Guo Xin-Yong
Acta Physica Sinica. 2002, 51 (12): 2901 doi: 10.7498/aps.51.2901
Full Text: [PDF 168 KB] Download:(864)
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Sun Mei-Sheng, Zheng Nan-Fang, Fang Xing-Hao, Kang Qiang, Li Zhong-Hai, Wang Lei, Sun Zhi, Yao Cheng-Gang
Acta Physica Sinica. 2002, 51 (12): 2906 doi: 10.7498/aps.51.2906
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null
GENERAL

The self-organized segregation effect of evolutionary minority game with imitation

Quan Hong-Jun, Wang Bing-Hong, Yang Wei-Song, Wang Wei-Ning, Luo Xiao-Shu
Acta Physica Sinica. 2002, 51 (12): 2667 doi: 10.7498/aps.51.2667
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A variant of the evolutionary minority game is proposed. Agents' strategies given by probabilities p can be changed by imitation. Numerical results show that the agents evolve into a state in which they selfsegregate into opposite groups characterized by extreme behaviours. The evolution by imitation can considerably enhance the system's coordination.

Application of fuzzy set theory to color image retrieval*

Liang Yan-Mei, Zhai Hong-Chen, Mu Guo-Guang
Acta Physica Sinica. 2002, 51 (12): 2671 doi: 10.7498/aps.51.2671
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We report an application of fuzzy relations in fuzzy set theory to the calculation of the similarity between colors, and apply it to the color image retrieval, where only a membership function is used as a measure of the similarity between the characteristic color vectors of a query image and of the images in the database. A match between two colors is defined as the α-cut fuzzy relation.In the comparison process, screening with decreasing by orders for comparisons and a method of regional color vector comparison are developed, which effectively reduce the color correlation in the red-green-blue (RGB) space and save from massive unnecessary calculations. Our theoretical and experimental results show clearly the advantages of our approach in both accuracy and speed of the color image retrieval.

Coherent soliton structures of a new (2+1) dimensional evolution equation

Zhang Jie-Fang, Huang Wen-Hua, Zheng Chun-Long
Acta Physica Sinica. 2002, 51 (12): 2676 doi: 10.7498/aps.51.2676
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null

Stability of the equilibrium state in relativistic Birkhoff systems*

Fu Jing-Li, Chen Li-Qun, Xue Yun, Luo Shao-Kai
Acta Physica Sinica. 2002, 51 (12): 2683 doi: 10.7498/aps.51.2683
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The stabilities of the equilibrium state in relativistic Birkhoff autonomous systems, relativistic Birkhoff semiautonomous systems and relativistic Birkhoff nonautonomous systems are studied .The equilibrium state equations are given. The disturbance equation and the first approximate equation are established. The stability criteria for the equilibrium state are obtained. The relationship between the stabilities of the equilibrium state in relativistic Birkhoff systems and classical Birkhoff systems is discussed. Several examples are presented to illustrate the results.

Four kinds of raising and lowering operators of the Landau system

Chen Chang-Ju, Tian Xu
Acta Physica Sinica. 2002, 51 (12): 2690 doi: 10.7498/aps.51.2690
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Using the centre operator and the initial mechanical momentum operator, four kinds of raising and lowering operators of a Landau system (planar charged particle moving in a uniform magnetic field) were derived and corresponding selection rules and conserved quantum number were discussed.

A Study on the double crisis vertex in a twoparameter plane*

Hong Ling, Xu Jian-Xue
Acta Physica Sinica. 2002, 51 (12): 2694 doi: 10.7498/aps.51.2694
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By means of GCMD method, a double crisis of sinusoidally forced oscillators is studied. A double crisis vertex in a two-parameter plane is determined, at which two curves of boundary crisis and two curves of interior crisis meet and four distinct crises coincide. Physically, small parameter perturbation (noise) about such a vertex induces drastic changes in the dynamical behaviour.

Unilaterally coupled synchronization of spatiotemporal chaos

Zhang Xu, Shen Ke
Acta Physica Sinica. 2002, 51 (12): 2702 doi: 10.7498/aps.51.2702
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Based on a coupled map lattice model, we present an approach of unilateral coupling to implement the synchronization of spatiotemporal chaos. Our numerical simulations show that the two spatiotemporal systems can accurately become synchronized by appropriately selecting the coupling strength and the equilibrium coefficient. We calculate the largest conditional Lyapunov exponent,so as to give the minimum coupling strength that can achieve the synchronization,and the functional relationship between the minimum coupling strength and the system parameters. The simulation results also indicate that this method is robust against noise.

Nonlinear continuous predictive variable structure control and synchronization of chaotic systems

Liu Fu-Cai, Wang Juan, Shi Miao, Gao Xiu-Wei
Acta Physica Sinica. 2002, 51 (12): 2707 doi: 10.7498/aps.51.2707
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This paper presents a predictive variable structure control method for the control and synchronization of chaotic nonlinear dynamic systems based on a unified frame for both the control and the synchronization. Two controllers are designed. One is the predictive controller for nominal model, and the other is a variable structure controller for system perturbation. The tracking control of reference signal is realized, and the method has the merit of robustness of variable structure control. The effectiveness of the proposed method are proved by numerical simulations.

A study on an improved Nagel-Schreckenberg traffic flow -model with open boundary conditions

Tian Hui-Li, Liu Mu-Ren, Kong Ling-Jiang
Acta Physica Sinica. 2002, 51 (12): 2713 doi: 10.7498/aps.51.2713
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Using the improved Nagel-Schreckenberg traffic model with open boundary conditions,we present the fundamental diagrams of traffic flow under different parameters by numerical simulation.It turns out that the traffic flow of the improved Nagel-Schrec-kenberg model is greater than that of the Nagel-Schreckenberg model,then we analyse the characters and critical points of the transition from free flow phase to maximum current phase and the transition from jamming phase to free flow phase.

Grassberger-Procaccia algorithm for evaluating the fractal characteristic of strange attractors

Wang An-Liang, Yang Chun-Xin
Acta Physica Sinica. 2002, 51 (12): 2719 doi: 10.7498/aps.51.2719
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Based on the three general strange attractors generated by the Lorenz equation, the Rssler equation and the Hénon map, the Grassberger-Procaccia algorithm is analyzed. For a finite time series, the sampling number, delay time, embedding dimension and the length of scaling region affect the precision of evaluating the correlation dimension D—2 and the 2nd-order Kolmogorov entropy K—2 by G-P algorithm. In the analysis of the trend of a correlation integral, the impression for a continuous dynamical system is different from that of a discrete dynamical system in delay time and embedding dimension. The criterion of delay time chosen by mutual information is unnecessary for calculating the correlation dimension D—2. The applicable conditions for G-P algorithm is also indicated.

Pressure difference between inside and outside of a drop and its critical radius in dropwise condensation

Min Jing-Chun
Acta Physica Sinica. 2002, 51 (12): 2730 doi: 10.7498/aps.51.2730
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It was proved using the thermodynamic method that the pressure difference between the inside and outside of a liquid drop sitting on a solid surface follows the classical Laplace equation, and this was further validated using the mechanics method. Such a pressure difference depends only on the surface tension of the liquid and the radius of the drop but is independent of the liquidsolid contact angle.Similarly, the critical radius of a drop in dropwise condensation is also independent of the contact angle and can be calculated using the classical Kalvin equation.
ATOMIC AND MOLECULAR PHYSICS

Theoretical calculation of the fine-structure and term energy of the excited states 1s~2 nd(n=3,4,5 of lithium-like systems

Ge Zi-Ming, Lv Zhi-Wei, Wang Zhi-Wen, Zhou Ya-Jun
Acta Physica Sinica. 2002, 51 (12): 2733 doi: 10.7498/aps.51.2733
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The fullcore plus correlation (FCPC) and the minimiziation of the expectation value of the Hamiltonian method is extended to calculate the nonreltivistic energies and the wave functions of 1s~2 nd(n=3,4,5) states for the lithium like systems from Z=11 to 20. The mass-polarization and the relativistic correction including the kinetic-energy correction, the Darwin term, the electron-electron contact term, and the orbitorbit interaction are calculated perturbatively as the first-order correction. The contribution from quantum electrodynamics (QED) is also included by using the effective nuclear charge formula. The excited energies, finestructure, and the termenergy are given and compared with other theoretical calculation and experimental results. It is shown that the correlative wave in the FCPC method embodies very well the strong correlation effect between the 1s~2 core and the valence electron.

Dielectronic recombination from Fe like Au^53+ to Ga like Au^47+ ions*

Yi You-Gen, Zheng Zhi-Jian, Yan Jun, Li Ping, Fang Quan-Yu, Qiu Yu-Bo
Acta Physica Sinica. 2002, 51 (12): 2740 doi: 10.7498/aps.51.2740
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Ab initio calculations of the rate coefficients for dielectronic recombination from Felike Au53+ to Galike Au48+ ions are performed based on Cowan's quasirelativistic multiconfiguration HartreeFockRelativistic code and distorted wave approaches. A large number of single excited states and doublyexcited states are included in the present calculation. Because of the extensive distribution of autoionization state energy levels and complicated cascade effects, the dielectronic recombination rate coefficients at higher Z are different from those at lower Z's. The results indicate that the error between our work and other theories is less then 10% in the diagnosed electron temperature and density. It is feasible to simulate the average ionized state and charge state distributions in a well characterized highly ionized Au plasma.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

Possibility of atmospheric pressure glow discharge in air

Wang Xin-Xin, Lu Ming-Ze, Pu Yi-Kang
Acta Physica Sinica. 2002, 51 (12): 2778 doi: 10.7498/aps.51.2778
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The atmospheric pressure discharge in an air gap between two dielectric barrier electrodes has been studied experimentally and the development of an electron avalanche in such an air gap was simulated numerically. The results show that, while it is possible to obtain glow discharge in an air gap not longer than 2 mm, the streamer discharge could only be obtained in an air gap longer than 5 mm if no methods could be used to lower the electric field when discharging. The "iontrapping mechanism", which was said to be responsible for the atmospheric pressure glow discharge, was not verified in the experiments.
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