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  • 简介:教学反思是教师成长永恒的主题,是教师成长的催化剂.美国心理学家波斯纳提出:“教师成长一经验+反思.”自我反思是反省、思考、探索和解决教育教学过程中各个方面存在的问题,具有研究的性质.通过反思,教师不断更新教学观念,改善教学行为,提升教学水平;同时形成自己对教学现象、教学问题的独立思考和创造性见解.可见教学反思犹如一位向导,引领教师走出“机械”运动,走向专业发展.反思不仅是提高教育教学质量的需要,也是教师专业成长的需要.对此结合本人的教学实践,谈谈自己的一些看法.

  • 标签: 教学反思 心理学家 教学过程 教学观念 教学行为 教学水平
  • 简介:当堂反馈1.压强是反映——的物理量.一辆“东风牌”汽车对地面的压强是1.8×10^4Pa它所表示的物理含义是——.

  • 标签: 压强 物理量 东风牌
  • 简介:Carbonsurfacewithlargeoxygenandcarbonratio(O/C)indicatedanoutstandingelectro-catalyticactivitytowardL-ascorbicacidoxidation,comparedtoplatinumgroupmetals.However,interrelationofsurfacefunctionalgroupsanditselectro-catalyticactivityisstillunclear.Inthispaper,weprepareddifferentlevelsofoxidizedcarbonsbyasimpleacidtreatmentandinvestigatedthecorrelationbetweenthesurfaceoxygenfunctionalgroupsofacid-treatedcarbonandelectro-catalyticactivityinanelectrooxidationofL-ascorbicacid.Positivelychargedcarbonwasdemonstratedbylonepairelectronofoxygenfromvalencebandspectrastudy.Itwasrevealedthatthepositivelychargedcarbon,especiallyinvolvedincarbonyl,showedenhancedtheelectro-catalyticactivitythroughbothbetteradsorptionofnegativelychargedreactantsandloweredLUMObyelectronegativityofoxygen.

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  • 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:数学是人们生活、劳动和学习必不可少的工具,为其它科学提供了语言、思想和方法,是一切重大技术发展的基础。要学好数学,就得激励学生的数学学习动机。本人通过多年的教学实践,在文中从个部分阐述了对学生数学学习动机的激励的认识:一、学生对学习的正确认识,是激发学习动机的前提;、应用恰当的方法,激发学生的学习动机,以期对激励学生的数学学习动机的进一步开展有所助益。

  • 标签: 数学 学习动机 激励前提 激励措施
  • 简介:Inthisarticle,theSm-dopingsinglecrystalsCa1-xSmxFe2As2(x=00.2)werepreparedbytheCaAsfluxmethod,andfollowedbyarapidquenchingtreatmentafterthehightemperaturegrowth.Thesampleswerecharacterizedbystructural,resistive,andmagneticmeasurements.ThesuccessfulSm-substitutionwasrevealedbythereductionofthelatticeparameterc,duetothesmallerionicradiusofSm3+thanCa2+.SuperconductivitywasobservedinallsampleswithonsetTcvaryingfrom27Kto44KuponSm-doping.ThecoexistenceofacollapsedphasetransitionandthesuperconductingtransitionwasfoundforthelowerSm-dopingsamples.ZeroresistivityandsubstantialsuperconductingvolumefractiononlyhappeninhigherSm-dopingcrystalswiththenominalx>0.10.Thedopingdependencesofthec-axislengthandonsetTcweresummarized.Thehigh-TcobservedinthesequenchedcrystalsmaybeattributedtosimultaneoustuningofelectroncarriersdopingandstraineffectcausedbylatticereductionofSm-substitution.

  • 标签: 掺杂晶体 超导电性 SM 单晶 晶格参数 淬火温度
  • 简介:Theground-stateandthermodynamicpropertiesofquantummixed-spinchainsof1/2-1/2-1-1and3/2-3/2-1-1areinvestigatedbyaquantumMonteCarlosimulationwiththeloop-clusteralgorithm.For1/2-1/2-1-1chain,wefindithastwophasesseparatedbyanenergy-gapvanishingpointintheground-state.For3/2-3/2-1-1chain,thenumericalresultsshowtwoenergy-gapvanishingpointsisolatedbydifferentphasesinitsground-state.Ourcalculationsindicatethatallthesegroundstatephasescanbeunderstoodbymeansofvalence-bond-solidpicture,andthethermodynamicbehavioratfinitetemperaturesiscontinuousasafunctionofparameterα=J2/J1.

  • 标签: 蒙特卡罗模拟 混合自旋链 铁磁性 基态 热力学性质 能隙
  • 简介:Thedipole-length,velocityandaecelerationabsorptionoscillatorstrengthsforthe1s^22p-ls^2nd(3_2=11to20arecalculatedusingtheenergiesandthemulticonfiguratloninteractionwavefunctionsobtainedfromafullcorepluscorrelationmethod.Theagreementbetweenthef-valuescalculatedfromthelength,velocityandaccelerationformulaeisexcellent.Ourresultsagreecloselywiththeexperimentaldataavailableintheliterature.Combiningthesediscreteoscillatorstrengthswiththesingle-channelquantumdefecttheory,thediscreteoscillatorstrengthsforthetransitionsfrom1s^22pstatetohighlyexcitedstates(n_>10)andtheoscillatorstrengthdensitiescorrespondingtothebound-freetransitionsareobtained.

  • 标签: 类锂系统 振荡器 量子缺陷 电离化原子系统 原子物理学
  • 简介:AnewgeneralizedJacobiellipticfunctionmethodisusedtoconstructtheexacttravellingwavesolutionsofnonlinearpartialdifferentialequations(PDEs)inaunifiedway.Themainideaofthismethodistotakefulladvantageoftheellipticequationwhichhasmorenewsolutions.Morenewdoublyperiodicandmultiplesolitonsolutionsareobtainedforthegeneralized(3+1)-dimensionalKronig-Penny(KP)equationwithvariablecoefficients.Thismethodcanbeappliedtootherequationswithvariablecoefficients.

  • 标签: 椭圆方程 孤立解 行波解 非线性偏微分方程 计算数学