学科分类
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74 个结果
  • 简介:Wedemonstrateanintegratedall-fibermid-infrared(mid-IR)supercontinuum(SC)sourcegeneratedbya1.95μmmasteroscillatorpoweramplifiersystemandasingle-modeZBLAN(ZrF4–BaF2–LaF3–AlF3–NaF)fiber.Themaximumaverageoutputpoweris10.67Wwithspectralbandwidthcoveringfrom~1.9to4.1μm.Thesingle-modeZBLANfiberandsilicafiberarethermal-splicedtoenhancetherobustnessandpracticabilityofthesystem.Itis,tothebestofourknowledge,thefirsthigh-powerintegratedcompactedall-fibermid-IRSCsourcebasedonthermal-splicedsilicafiberandZBLANfiber.

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  • 简介:WedemonstrateastableconventionalsolitoninaTm-dopedhybridmode-lockedfiberlaserbyemployingahomemadeall-fiberLyotfilter(AFLF)andasingle-wallcarbonnanotube.TheAFLF,designedbysandwichingapieceofpolarization-maintainedfiber(PMF)withtwo45°tiltedfibergratingsinscribedbyaUVlaserinPMFwithaphase-maskscanningtechnique,showslargefilterdepthof~9dBandsmallinsertionlossof~0.8dB.ByoptimizingthefreespectralrangeoftheAFLF,theKellysidebandsofaconventionalsolitoncenteredat1966.4nmcanbedramaticallysuppressedwithoutimpairingthemainshapeofthesolitonspectrum.Itgivesthepulsedurationof1.18psandbandwidthof3.8nm.ByadjustingthetemperatureofthePMFoftheAFLFfrom7°Cto60°C,wavelengthtunablesolitonpulsesrangingfrom1971.62nmto1952.63nmarealsoobtained.Thegeneratedsolitonpulsescanbepreciselytunedbetween1971.62nmand1952.63nmbycontrollingthetemperatureoftheAFLF.

  • 标签: KELLY SUPPRESSION WAVELENGTH
  • 简介:Byusingtheultrasound-assistedliquidphaseexfoliationmethod,Bi2Te3nanosheetsaresynthesizedanddepositedontoaquartzplatetoformakindofsaturableabsorber(SA),inwhichnonlinearabsorptionpropertiesaround2μmareanalyzedwithahome-mademode-lockedlaser.Withtheas-preparedBi2Te3SAemployed,astablepassivelyQ-switchedall-solid-state2μmlaserissuccessfullyrealized.Q-switchedpulseswithamaximumaverageoutputpowerof2.03Waregeneratedunderanoutputcouplingof5%,correspondingtothemaximumsingle-pulseenergyof18.4μJandpeakpowerof23W.Thedeliveredshortestpulsedurationandmaximumrepetitionrateare620nsand118kHzunderanoutputcouplingof2%,respectively.ItisthefirstpresentationofsuchBi2Te3SAemployedinasolid-stateQ-switchedcrystallinelaserat2μm,tothebestofourknowledge.Incomparisonwithother2Dmaterialssuitableforpulsed2μmlasers,thesaturableabsorptionperformanceofBi2Te3SAisprovedtobepromisingingeneratinghighpowerandhigh-repetition-rate2μmlaserpulses.

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  • 简介:Theeffectandmechanismofcarmustine(BCNU)combinedwithall-transretinoicacid(ATRA)ontheapoptosisofhumanglioblastomaU251cellswereinvestigatedbymeansof3-(4,5-dimethylthiazol-2-yl)-2,5-diphe-nyltetrazoliumbromide(MTT)assay,flowcytometry,reversetranscription-polymerasechainreaction(RT-PCR)andWesternblotanalysis.TheresultsshowthatBCNUorATRAshowstime-anddose-dependentinhibitioneffectsonhumanglioblastomaU251cellsandthecombinationofBCNUwithATRAshowsansynergisticinhibitioneffectonhumanglioblastomaU251cells,andthecombinedBCNUandATRAcansignificantlyinhibittheproliferationofhumanglioblastomaU251cells,andinducetheapoptosisofthem,makingthecellsarrestinthestageofG1phase,thestageofSandG2phasesdecline,therateoftheapoptosisofhumanglioblastomaU251cellsincrease,thecorrespondingmRNAexpressionofcyclinEandcyclin-dependentkinase2(CDK2)downregulatedandthecorrespon-dingmRNAexpressionofp27kip1unregulated.Inaddition,thecombinedBCNUandATRAreducedtheproteinexpressionofnuclearfactorkappaB(NF-κB).Takentogether,theseresultssuggestthatthetreatmentofhumanglioblastomaU251cellswithacombinationapplicationofATRAandBCNUcanexertsynergisticeffect,thecourseofthiskindofcombinationchemotherapymaylikelybeassociatedwithmultiplemolecularmechanismsforapoptosis,furthermore,thecyclinEandp27kip1shouldbeconsideredasnoveltargetsforcontrollingthegrowthofglioblastomacells.

  • 标签: 全反式维甲酸 脑胶质瘤 细胞凋亡 细胞周期素 卡莫司汀 细胞周期蛋白依赖性激酶
  • 简介:在旅行波浪转变下面,一些非线性的部分微分方程例如Camassa河边肥沃的低地方程,高顺序的KdV方程,等等,被归结为u″表示的一首integrable颂诗+p(u)(u')2+q(u)=0答案能被给其将军。而且,为多项式联合完全的辨别系统,这些方程的所有单个旅行波浪答案的分类被获得。方程u″0包括的+p(u)(u')2+q(u)=是的方程(u')2=f(u)一种特殊情况,建议方法能也因此被用于很多非线性的方程。这些完全的结果不能被任何间接方法获得。

  • 标签: 数学物理方法 非线性数学物理方程 孤波解 对称群 非线性偏微分方程
  • 简介:Thesuppressionoftherecombinationofelectronsandholes(e–h)andtheenhancementofthelightabsorptionofsemiconductorsaretwokeypointstowardefficientphotocatalyticdegradation.Here,wereportafew-layerg-C3N4/α-MoO3nanoneedles(flg-C3N4/α-MoO3NNs)all-solid-stateZ-schememechanismphotocatalystsynthesizedviaatypicalhydrothermalmethodinacontrolledmanner.Therecombinationofthephoto-inducede–hpairscouldbeeffectivelyrestrainedbytheZ-schemepassagewaybetweentheflg-C3N4andα-MoO3NNsinthecomposite,whichcouldalsopromiseahighredoxabilitytodegradepollutants.Anditbecamepossibleforthepreparedphotocatalysttoabsorblightinawiderangeofwavelengths.Thedetailedmechanismwasstudiedbyelectronspin-resonancespectroscopy(ESR).Thelow-dimensionalnanostructureofthetwoconstituents(α-MoO3NNswithone-dimensionalstructureandflg-C3N4withtwo-dimensionalstructure)endowedthecompositewithvarietiesofexcellentphysicochemicalproperties,whichfacilitatedthetransferanddiffusionofthephotoelectronsandincreasedthespecificsurfaceareaandtheactivesites.The10wt%flg-C3N4/α-MoO3NNsshowedthebestphotocatalyticperformancetowardRhBdegradation,therateofwhichwas71.86%,~2.6timeshigherthanthatofα-MoO3NNs.

  • 标签: Flg-C3N4 α-MoO3 NANONEEDLES ALL-SOLID-STATE Z-scheme mechanism
  • 简介:本文在对1990~1999年安徽医科大学第一附属医院收治的3450例0~7岁儿童因发生伤害而住院治疗的病例进行归纳整理的基础上,运用模糊综合评价的方法,分析了不同年龄段儿童伤害原因与康复状况的关系,针对性地提出了预防儿童伤害事故发生的有效措施。

  • 标签: 儿童 伤害 预防 模糊综合评价
  • 简介:WereportQ-switchedandmode-lockederbium-dopedall-fiberlasersusingternaryReS2(1-x)Se2xassaturableabsorbers(SAs).ThemodulationdepthandsaturableintensityofthefilmSAare1.8%and0.046MW∕cm2.InQ-switchedmechanismoutput,thepulsewascenteredat1531.1nmwithmaximumpulseenergyandminimumpulsewidthof28.29nJand1.07μs,respectively.Inmode-lockedoperation,thepulsewascenteredat1561.15nmwithpulsewidthof888fs,repetitionrateof2.95MHz,andmaximumpulseenergyof0.275nJ.Tothebestofourknowledge,thisisthefirstreportonthemode-lockedEr3+-dopedfiberlaserusingternarytransitionmetaldichalcogenides.Thisworksuggestsprospective2D-materialSAscanbewidelyusedinversatilefieldsduetotheirattractiveoptoelectronicandtunableenergybandgapproperties.

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  • 简介:麦兜是一只单纯乐观,资质平平的猪,他也有很多梦想,在最新上映的《春田花花同学会》里,哪怕是最微不足道的快乐,好比简简单单一个“斋卤味”都可以被当成奥运冠军般浓墨重彩地歌颂。在麦兜的世界里,快乐就是这样单纯的事情,

  • 标签: 儿童 单纯
  • 简介:自20世纪90年代以来,脑科学在人类社会进步中正在起着越来越重要的作用,也受到越来越广泛的重视。从美国"脑的10年",到日本"脑科学时代计划",无一不显示出脑与认知科学在国际生命科学研究领域中的重要地位。在我国,脑与认知科学的研究也受到了应有的重视。杨雄里院士主持的"脑功能和脑重大疾病的基础研究"(1999-2004)、郭爱克院士主持的"脑发育和可塑性的基础研究"(2000-2005)等重大课题均取得了重大进展。

  • 标签: 珠心算 脑科学 脑机制研究 儿童智能 基础研究 杨雄里
  • 简介:儿童珠心算教育与人类的智力开发(下)谢大文苑玉敏三、儿童早期珠心算教育,是培育人脑机能的最佳时期和优良方法为什么是“最佳时期”。我国各地珠心算教育的实践揭示,在4岁—12岁之间的儿童中最适合实施珠心算教育。一般都选择在幼儿园的儿童和小学的学生中施教。...

  • 标签: 珠心算教育 智力开发 幼儿园儿童 教育与人 人类智力 脑功能
  • 简介:《义务教育数学课程标准(2011)》在其总体目标阐述中写道:“获得适应未来社会生活和进一步发展所必需的重要数学知识(包括数学事实、数学活动经验)以及基本的数学思想方法和必要的应用技能.”在这一目标的阐述中数学知识不仅包括客观的、事实性的知识,还包括学习过程中产生的带有鲜明个体认知特征的、属于个人的数学活动经验.教学中关注数学活动经验,是课程标准的要求,也是提高数学课堂教学有效性的策略.

  • 标签: 数学知识 教材 数学课程标准 数学课堂教学 解读 儿童
  • 简介:参照欧盟玩具安全(2009/48/EC号)指令的要求,应用电感耦合等离子体原子发射光谱法(ICP-AES)测定儿童用品材料中17种元素迁移量.样品主要有儿童玩具、童车、学生用品和儿童家具四大类别.共计测试样品337批,测试样品数为1029个.实验结果表明,部分样品中有铝、钡、镉、铬、铜、铅、锰、锶和锌检出,部分样品中铅、镉迁移量超过欧盟玩具安全新指令限量要求.

  • 标签: 欧盟 儿童用品 元素迁移