学科分类
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500 个结果
  • 简介:WehavestudiedtheangularmagnetoresistanceofironpnictidesBaFe2-xNixAs2,whichshowsclear180degreeperiodicityasfittedbyacosinefunction.Inthex=0.065sample,thephaseofthetwo-foldsymmetrychanges90degreesabovethetetragonal-to-orthorhombicstructuraltransitiontemperatureTs.Sincethephaseatlowtemperatureisassociatedwiththerotationoforthorhombicdomainsbymagneticfield,weshowthatevenvacuumgreasecanpushthepresenceoforthorhombicdomainsattemperaturesmuchhigherthanTs.Ourresultssuggestthatresidualstressmayhavesignificanteffectsinstudyingthenematicordersanditsfluctuationsinironpnictides.

  • 标签: 残余应力 磁电阻 转变温度 函数拟合 斜方晶系 周期性
  • 简介:Wereporteddiversesolitonoperationsinathulium/holmium-dopedfiberlaserbytakingadvantageofataperedfiber-basedtopologicalinsulator(TI)Bi2Te3saturableabsorber(SA).TheSAhadanonsaturablelossof53.5%andamodulationdepthof9.8%.Stablefundamentallymode-lockedsolitonsat1909.5nmwithdistinctKellysidebandsontheoutputspectrum,apulserepetitionrateof21.5MHz,andameasuredpulsewidthof1.26pswereobservedinthework.Byincreasingthepumppower,bothbunchedsolitonswithsolitonnumberupto15andharmonicallymode-lockedsolitonswithharmonicorderupto10wereobtained.Toourknowledge,thisisthefirstreportofbothbunchedsolitonsandharmonicallymode-lockedsolitonsinafiberlaserat2μmregionincorporatedwithTIs.

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  • 简介:Mode-andpolarization-divisionmultiplexingoffernewdimensionstoincreasethetransmissioncapacityofopticalcommunications.Selectiveswitchesarekeycomponentsinreconfigurableopticalnetworknodes.Anon-chipsilicon2×2mode-andpolarization-selectiveswitchthatcanroutefourdatachannelsontwomodesandtwopolarizationssimultaneouslyisproposedandexperimentallydemonstratedforthefirsttime,tothebestofourknowledge.Theoverallinsertionlossesarelowerthan8.6dB.Toreducetheinter-modalcrosstalk,polarizationbeamsplittersareaddedtofiltertheundesiredpolarizationsormodes.Themeasuredinter-modalandintra-modalcrosstalkvaluesarebelow-23.2and-22.8dBforallthechannels,respectively.

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  • 简介:TheAlkalineThermalTreatment(ATT)ofbiomassisoneofthefewbiomassconversionprocessesthathasapotentialforBECCS(bio-energywithcarboncaptureandstorage).Combiningin-situcarboncapturewithcreatesacarbon-neutralprocessthathasthepotentialtobecarbon-negative.Thisstudyhasshownthattheconversionofcellulosetosuppressedcanbeachievedthroughthereformingofgaseousintermediatesinafixedbedof10%Ni/ZrO2.Reformingoccursatlowtemperatures≤773K,whichcouldallowforimprovedsustainability.

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  • 简介:TheapplicationofLanthanumBromide(LaBr3)detectorsprovidesauniqueopportunitytomeasurelifetimeofexcitedstatesinpicosecond-nanosecondregion.Reducingthebackgroundisofcriticalimportancetogetpreciseresults.Forsomeexcitedstatesfeedingfromisomerswithlifetimelongerthan1μs,itcanbeachievedbytheSpectrometerforHeavyAtomandNuclearStructure(SHANS)[1].143Eunucleiwerepopulatedviathe123Sb(24Mg,4n)fusion-evaporationreaction.Mostoftheevaporationresiduesatgroundstateorlong-livedisomersweretransferredtodetectionterminalafteraflightofabout1.4μsinSHANS.Inthecaseof143Eu,threetransitionshavebeenobserved(Fig.1).

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  • 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.

  • 标签: 反应概率 动力学计算 上海 量子 表面 截面曲线
  • 简介:Therearetwokindsofchargingmodeoftheohmpowersupply.Whenthedeviceworksnormallyandtheplasmabreakdownvoltageislow,theohmpowersupplywillruninthelogicalnon-loopcurrentmodewhichcurrentissymmetrical,butwhenthedischargingconditionisnotverywellandtheplasmabreakdownvoltageishigh,theunsymmetricalmodewillbeadopt,i.e.switchingoffthepositiverectifier,

  • 标签: HL-2A 欧姆击穿电源 放电设计 反向整流器
  • 简介:1.如图所示,将码货放在玻璃杯的塑料盖板上。用塑料尺快速地敲出塑料板,鸡蛋没有随塑料板一起运动,而是向下落进杯子里,原因是鸡蛋和塑料板原来均处于________状态,塑料板受力改变运动状态后,鸡蛋要保持________状态。鸡蛋下落是受到__________力的作用.

  • 标签: 牛顿第一定律 运动状态 塑料板 玻璃杯 鸡蛋