简介:Thispaperreviewsthestudiesonacoustoelectriceffectinextrinsicsemiconductormaterialsusedinvariousscientificandothermeasurements.Ahistoricalreviewofearlierfindingsisgivenwithspecialreferencetoassociatedmechanisms.Acoustoelectricstudiesinsolidstatedevioesrequirefurtherattentionandtheworkdoneinthisareaisalsodiscussed.
简介:Photoconductiveswitcheswerethekeycomponentsthatallowedthegenerationanddetectionofcoherentbroadbandelectromagneticpulsesatterahertzfrequencies,openingthepossibilityforperformingspectroscopyand,therefore,measuringcomplexdielectricpropertiesofmaterialsinthisband,whichwasmostlyunexplored.Inthispaper,wepresentabriefintroductiontotheoperationprinciplesofthesedevices.Subsequently,wepresentareviewofthecurrentstate-of-the-artinthisfieldanddiscussthechallengestobefacedinfuturedevelopmentofthesedevices.
简介:Wereviewcurrentsiliconphotonicdevicesandtheirperformanceinconnectionwithenergyconsumption.Fourcriticalissuesareidentifiedtolowerenergyconsumptionindevicesandsystems:reducingtheinfluenceofthethermo-opticeffect,increasingthewall-plugefficiencyoflasersonsilicon,optimizingenergyperformanceofmodulators,andenhancingthesensitivityofphotodetectors.Majorconclusionsare(1)Mach–Zehnderinterferometer-baseddevicescanachieveathermalperformancewithoutanyextraenergyconsumptionwhilemicroringsdonothaveanefficientpassiveathermalsolution;(2)whiledirectbondedIII–V-basedSilaserscanmeetsystempowerrequirementfornow,hetero-epitaxialgrownIII–Vquantumdotlasersarecompetitiveandmaybeabetteroptionforthefuture;(3)resonantmodulators,especiallycouplingmodulators,arepromisingforlow-energyconsumptionoperationevenwhenthepowertostabilizetheiroperationisincluded;(4)benefitingfromhighsensitivityandlowcost,Ge/Siavalanchephotodiodeisthemostpromisingphotodetectorandcanbeusedtoeffectivelyreducetheopticallinkpowerbudget.Theseanalysesandsolutionswillcontributetofurtherloweringenergyconsumptiontomeetaggressiveenergydemandsinfuturesystems.
简介:混合象粉末那样的微粒是在包括药品的许多工业的一个重要过程,塑料,家庭产品(例如detergents)并且食物处理。产品的质量取决于他们接着取决于几何设计和操作条件的成分材料混合的度。由于在混合器几何学和小粒的材料之间的相互作用的理解的缺乏,不幸地,有限进步在优化混合器设计被取得了。分离元素方法(DEM)是允许粒子系统被模仿并且混合被预言的一种计算技术。模拟是在困难或昂贵用传统的试验性的途径获得的不同混合器的表演上获得信息的一个有效方法。这里,我们表明DEM怎么能被用来解开流动动力学并且评定在设备的几种不同类型混合。这些设备使用了混合或微粒的使成粒状,当控制的严肃,bladed和高度砍,广泛地被分类。我们也在混合表演和使用DEM测试弗鲁德数字可伸缩是否对预言旋转混合器的规模性能合适探索粒子形状的角色。
简介:Nanostructuredcarbonmaterials,includingcarbonnanotubes,grapheneandnanoporouscarbon,showpromiseforexpandingrenewableenergy.Inparticular,theconfigurationandelectronicpropertiesofgrapheneedgesinrelationwiththeirelectrochemicalactivityhavebecomeamajorissueincarbon-basedenergystoragedevices.Here,wereviewrecentresultsconcerningtheimportantrolesofgrapheneedgesasthegatewayforlithiumionintercalationintheanodeoflithium-ionbatteries,aspromotersofhighcapacitanceincarbon-basedsupercapacitors,andasanchoringsitesforPtnanoparticlesinfuelcells.Weenvisagethatthecontrolledsynthesisofaspecific,clean,andstableedgeconfigurationcouldbeachievedtomaximizetheelectrochemicalperformanceofnanostructuredcarbon-basedenergystoragedevices.
简介:磁性的聚合物粒子在象生物医学的治疗,诊断和分离技术那样的多样的区域发现了应用。这些应用要求粒子控制了尺寸和狭窄的尺寸分布在使用获得更好的控制和重制度。这份报纸在nano规模在磁性的聚合物粒子的准备考察最近的开发并且由包含磁性的部件与微规模溶解或在situ形成了聚合物。用乳化和埋入方法的粒子制造在微规模的尺寸生产磁性的聚合物粒子。然而,在用常规乳化方法的这个范围的粒子的生产在粒子尺寸和多分散性上负担得起很有限的控制。我们在使用膜和microfluidics乳化技术的其他的线路上报导,它有一个能力生产monodisperse乳剂和聚合物microspheres(与不到10%的变化的系数)在到一些100m的从submicrometer的范围。这些生产方法的表演考虑到未来应用被估计。
简介:Ametallicnanostructuredarraythatscattersradiationtowardathinmetalliclayergeneratessurfaceplasmonresonancesfornormallyincidentlight.Thelocationoftheminimumofthespectralreflectivityservestodetectchangesintheindexofrefractionofthemediumunderanalysis.Thenormalincidenceoperationeasesitsintegrationwithopticalfibers.Thegeometryofthearrangementandthematerialselectionarechangedtooptimizesomeperformanceparametersassensitivity,figureofmerit,fieldenhancement,andspectralwidth.Thisoptimizationtakesintoaccountthefeasibilityofthefabrication.Theevaluatedresultsofsensitivity(1020nm/RIU)andfigureofmerit(614RIU-1)arecompetitivewiththosepreviouslyreported.
简介:一般来说,量钥匙分发(QKD)由于量无常原则,量noncloning定理和意味着量不能进一步被划分的量nondividing原则为完美的设备被证明无条件地安全。然而,在系统使用的实际光、电的设备是有瑕疵的,它能被偷听者部分利用到或完全侦察在合法聚会之间的秘密钥匙。在这篇文章,我们简短首先在量关于国际性地执行的有瑕疵的设备砍在一些试验性的QKD系统上上考察最近的工作,然后,我们将在细节介绍我们的最近的砍工作包括被动法拉第镜子攻击,部分随机的阶段攻击,选择波长的photon-number-splitting攻击,频率移动攻击,和single-photon-detector攻击。那些量攻击提醒人改进安全由简单地增加反措施或采用象测量设备独立人士协议那样的一个完全不同的协议避免量砍在测量设备的瑕疵上由于有瑕疵的设备在实际QKD系统存在[Lo,等,Phys。加快。Lett,2012,108:130503]。
简介:Wereviewthestateoftheartandourperspectivesonsiliconandhybridsiliconphotonicdevicesforopticalinterconnectsindatacenters.Afterabriefdiscussionofthekeyrequirementsforintra-datacenteropticalinterconnects,weproposeawavelength-division-multiplexing(WDM)-basedopticalinterconnectforintra-datacenterapplications.Followingourproposedinterconnectsconfiguration,thebulkofthereviewemphasizesrecentdevelopmentsconcerningon-chiphybridsiliconmicrolasersandWDMtransmitters,andsiliconphotonicswitchfabricsforintra-datacenters.ForhybridsiliconmicrolasersandWDMtransmitters,weoutlinetheremainingchallengesandkeyissuestowardrealizinglowpowerconsumption,directmodulation,andintegrationofmultiwavelengthmicrolaserarrays.Forsiliconphotonicswitchfabrics,wereviewvarioustopologiesandconfigurationsofhigh-port-countN-by-NswitchfabricsusingMach–Zehnderinterferometersandmicroringresonatorsasswitchelements,anddiscusstheirprospectstowardpracticalimplementationswithactivereconfiguration.Forthemicroring-basedswitchfabrics,wereviewrecentdevelopmentsofactivestabilizationschemesatthesubsystemlevel.Last,weoutlineseverallargechallengesandproblemsforsiliconandhybridsiliconphotonicstomeetforintra-datacenterapplicationsandproposepotentialsolutions.
简介:Inthispaper,photoexcitationprocessesinthebilayerdevicesbasedoninorganicmaterialsandpoly(N-vinyl-carbazole)(PVK)wereinvestigated.Inordertoclarifytherolesofinorganicmaterialsinphotoconductivepropertiesofbilayerdevices,TiO2andZnSwerechosentocombinewithPVK.Amodelforgenerationofphotocurrent(Iph)insinglelayerdeviceofPVKwasobtained.Itisdeducedthattherecombinationrateconstant(Pcomb)andtheionizationrateconstant(γ)ofexcitonsshouldbeconsideredasthemostimportantfactorsforIph.Forinorganicmaterials(TiO2orZnS)/PVKbilayerdevices,inreversebiasof-4V,thephotocurrentof115mA/cm2intheTiO2/PVKdevicewasobserved,butthephotocurrentintheZnS/PVKdevicewasonly10mA/cm2undertheilluminationlightof340nmandthelightintensityof14.2mW/cm2.TheweakerphotocurrentisattributedtotheabsorptionofZnSwithinUVregionandtheenergyoffsetattheinterfacebetweenPVKandZnS,whichimpedesthetransportofchargecarriers.
简介:Wedemonstratelow-losshydrogenatedamorphoussilicon(a-Si:H)waveguidesbyhot-wirechemicalvapordeposition(HWCVD).Theeffectofhydrogenationina-SiatdifferentdepositiontemperatureshasbeeninvestigatedandanalyzedbyRamanspectroscopy.Weobtainedanopticalqualitya-Si:Hwaveguidedepositedat230°CthathasastrongRamanpeakshiftat480cm-1,peakwidth(fullwidthathalf-maximum)of68.9cm-1,andbondangledeviationof8.98°.Opticaltransmissionmeasurementshowsalowpropagationlossof0.8dB/cmatthe1550nmwavelength,whichisthefirst,toourknowledge,reportforaHWCVDa-Si:Hwaveguide.
简介:Wehavefabricatedatop-emittingorganiclight-emittingdeviceonsiliconsubstratewithhighyellowluminancebasedon5,6,11,12-tetraphenylnaphthacenesub-monolayer.Itconsistsofathinlayerofhighlyconductivesilverasthesemitransparentcathodeandsurfaced-modifiedAgastheanode.Thedeviceturnsonat3Vwiththeluminanceof8.4cd/m^2.Themaximumcurrentefficiencyis1.3cd/Aat6Vandtheluminancereaches14790cd/m^2at14V.Theperformanceofthedeviceisexcellentintop-emittingorganiclight-emittingdevicesaccordingtoourknowledge.