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108 个结果
  • 简介:采用共孔径发射和接收技术可使激光信标系统结构紧凑、控制简单。在激光的共孔径发射和接收中使用偏振耦合分光方法有分光效率高、简单可靠等优点。但是,组成地平式折轴望远镜的反射镜对s光和p光的相位延迟有差异,望远镜旋转造成的激光偏振态变化更严重地影响了偏振分光的接收效率。要保持较高的接收效率,就需要对激光相位进行动态补偿。

  • 标签: 相位延迟 分光系统 偏振耦合 反射镜 孔径 测量
  • 简介:Asimplemethodisappliedtocalculatingtheisotopeshifts(ISs)on5S1/2→4D3/2,5/2transitionsof87,88Sr+.FirstwehavecalculatedtheISsoflowertransitionsonaseriesofalkali-likesystemssuchasB2+,Ca+andBa+,whichareinagreementwithotherworks.ThentheISson5S1/2→4D3/2,5/2transitionsof87,88Sr+,whichareusefultostudytheSr+opticalfrequencystandard,areevaluated.

  • 标签: 原子物理 同位素位移 5S1/2→4D3/2 5/2 精细结构
  • 简介:AnewlayeredCu-basedoxychalcogenideBa3Fe2O5Cu2S2hasbeensynthesizedanditsmagneticandelectronicpropertieswererevealed.Ba3Fe2O5Cu2S2isbuiltupbyalternativelystacking[Cu2S2]2-layersandironperovskiteoxide[(FeO2)(BaO)(FeO2)]2-layersalongthecaxisthatareseparatedbybariumionswithFe3+fivefoldcoordinatedbyasquare-pyramidalarrangementofoxygen.Fromthebondvalencearguments,weinferredthatinlayeredCuCh-based(Ch=S,Se,Te)compoundsthe+3cationinperovskiteoxidesheetprefersasquarepyramidalsite,whilethelowervalencecationprefersthesquareplanarsites.Thestudiesonsusceptibility,transport,andopticalreflectivityindicatethatBa3Fe2O5Cu2S2isanantiferromagneticsemiconductorwithaNe′eltemperatureof121Kandanopticalbandgapof1.03eV.Themeasurementofheatcapacityfrom10Ktoroomtemperatureshowsnoanomalyat121K.TheDebyetemperatureisdeterminedtobe113K.TheoreticalcalculationsindicatethattheconductionbandminimumispredominantlycontributedbyO2pand3dstatesofFeionsthatantiferromagneticallyarrangedinFeO2layers.TheFe3dstatesarelocatedatlowerenergyandresultinanarrowbandgapincomparisonwiththatoftheisostructuralSr3Sc2O5Cu2S2.

  • 标签: 钙钛矿型氧化物 铁磁半导体 光学带隙 德拜温度 电子性质 阳离子
  • 简介:Wehavedevelopedacost-effectiveandhighlycompact100-Gb/scoarsewavelengthdivisionmultiplexing(CWDM)transmitteropticalsubassembly(TOSA)usinglens-freehybridintegration.Toachievelargealignmenttolerances,distributedfeedbacklaserdiodes(DFB-LDs)arebutt-coupledtoafour-channelsilica-basedplanarlightwavecircuit(PLC)arrayedwaveguidegrating,withthesiliconsub-mountsandPLCadhesivelybonded.Then,aflexibleprintedcircuitisemployedtoconnecttheinternalDFB-LDsandtheexterioroftheTOSApackageforradiofrequencysignaltransmission,eliminatingtheexpensiveceramicfeed-through.ThepackagedCWDMTOSA,whichis15.8mm×7.0mm×6.0mminsize,showsaside-modesuppressionratioof>40dB,a3dBbandwidthof>18GHz,anderror-freetransmissionwithanaverageopticaloutputpowerof>0dBmanddynamicextinctionratioof>4.0dBat25.78125Gb/sovera10kmsingle-modefiberforallfourlanes.

  • 标签: DFB PLC AWG Figure LOW-COST HYBRID
  • 简介:Inthispaper,asurfacepotentialbasedthresholdvoltagemodeloffully-depleted(FD)recessed-source/drain(Re-S/D)silicon-on-insulator(SOI)metal-oxidesemiconductorfield-effecttransistor(MOSFET)ispresentedwhileconsideringtheeffectsofhigh-kgate-dielectricmaterialinducedfringing-field.Thetwo-dimensional(2D)Poisson’sequationissolvedinachannelregioninordertoobtainthesurfacepotentialundertheassumptionoftheparabolicpotentialprofileinthetransversedirectionofthechannelwithappropriateboundaryconditions.Theaccuracyofthemodelisverifiedbycomparingthemodel’sresultswiththe2DsimulationresultsfromATLASoverawiderangeofchannellengthsandotherparameters,includingthedielectricconstantofgate-dielectricmaterial.

  • 标签: MOSFET 电压模型 SOI 金属氧化物半导体场效应晶体管 空间 阈值
  • 简介:研究目的:研究新型磁性回热填料Gd2O2S对液氦温区高频脉管制冷机多级回热器损失特性的影响。创新要点:确定了不同回热填料以及运行参数(频率、平均压力)下液氦温区多级脉管制冷机的制冷温度和各级预冷量,进一步明确了4K高频回热损失机理。研究方法:采用理论研究与实验验证相结合的方法,基于一台两级G-M型低频脉管制冷机预冷的单极斯特林型高频脉管制冷机,研究多级回热器在高频以及4K温区下的损失特性。选取新型回热填料Gd2O2S替代部分回热填料HoCu2,比较回热器采用两种填料时在不吲运行频率及平均压力下的冷端制冷温度(图10)、各级预冷量和预冷温度(图1112)。重要结论:采用孔隙率较小的新型磁性回热填料Gd2O2S可显著改善第一级回热器内压力波与质量流的相位关系,从而减小该级回热损失。减小平均压力可以降低制冷机无负荷制冷温度并减小第二级预冷量,但制冷工质氦的体积比热容会急剧增大,从而使低温级回热器的换热对频率非常敏感。此外,频率对高温级回热器的回热特性影响不明显。该方法可以为三级斯特林型4K多级脉管制冷机提供设计依据。

  • 标签: 斯特林型脉管制冷机 回热填料 4K 高频 预冷 低温惯性管
  • 简介:Thereisagrowingsupportforthelowlyingscalarmesonsf0(500),f0(980),a0(980),and(800)tobegenerateddynamicallyfromtheinteractionofpseudoscalarmesons,whilethecaseofthenextsetofscalarresonancesathigherenergies,f0(1370),f0(1710),K0(1430)ismoreaquestionofdebate.Soisthecaseofthetensorresonancesf2(1270),f′2(1525),K2(1430).AnewperspectiveonthesestateshasbeenofferedinRef.[1]wherethef0(1370)andf2(1270)resonancesareshowntobegeneratedfromtheinteractionprovidedbythelocalhiddengaugeLagrangiansimplementingunitarization.Itisshownthattheideaofthenatureofthesestatesasvectormeson-vectormesoncompositestateshasbeentestedinmanyreactions.Yet,thepermanentdiscussionoftheissuedemandsextrachecksforotherobservablesand,inthissense,theweakdecaysbringanewsourceofvaluableinformationthatshouldservetotestdifferentmodels.

  • 标签: J/Ψ source case SENSE NEXT IDEA
  • 简介:ThephysicalmodeldescribingtheYin-Yangbalanceinthetai-chidiagramviathemeltingandfreezingprocessesinarotatingdevicepresentedinparts1and2isfurtherdevelopedforthecontemporarytai-chidiagramandintheyuan-chidiagram.Thecontemporarytai-chidiagramshowninFig.1isasimplificationformoftheancienttai-chidiagrampresentedinReference[2].Therearetwosemi-circlesformingtheinterfacecurvebetweentheyinandyanginthecontemporarytai-chidiagram.Byknowingthelocationoftheinterfacebetweentheyinandyanginthecontemporarytai-chidiagram,therequirementforthesimulationmodelistofindtheconditiontomatchtheinterfacelocation.Thesimplificationchangesnotonlythestructurebutalsothephysicalinsightoftheancienttai-chidiagram,whichwillbedescribedinthepresentstudy.Theyuan-chidiagramshowninFig.2isthecombinationoftheMasterChen’stai-chidiagrampresentedinReferences[1,2]andthecontemporarytai-chidiagram.Th

  • 标签: Tai-chi DIAGRAM Yuan-chi DIAGRAM Fu Xi’s