简介:Dopantsanddefectsareimportantinsemiconductorandmagneticdevices.Strategiesforcontrollingdopinganddefectshavebeenthefocusofsemiconductorphysicsresearchduringthepastdecadesandremaincriticaleventoday.Co-dopingisapromisingstrategythatcanbeusedforeffectivelytuningthedopantpopulations,electronicproperties,andmagneticproperties.Itcanenhancethesolubilityofdopantsandimprovethestabilityofdesireddefects.Duringthepast20years,significantexperimentalandtheoreticaleffortshavebeendevotedtostudyingthecharacteristicsofco-doping.Inthisarticle,wefirstreviewthehistoricaldevelopmentofco-doping.Then,wereviewavarietyofresearchperformedonco-doping,basedonthecompensatingnatureofco-dopants.Finally,wereviewtheeffectsofcontaminationandsurfactantsthatcanexplainthegeneralmechanismsofco-doping.
简介:摘要:随着绿建工程的不断普及,绿色工程的验收标准也有了新的定义,即:在全寿命期内、节约资源、保护环境、减少污染,为人们提供健康、适用、高效的使用空间,最大限度地实现人与自然和谐共生的高质量建筑。
简介:Amethodbasedupontheweightedtotalcrosssection(WTCS)theoryisproposedtocalculatethephoto-ionisationcrosssectionsandtheradiativerecombinationratecoefficientsbetweenthefundamentallevelofCOandthemainelectronicstatesofitscorrespondingion.Totalphoto-ionisationcrosssectionsandradiativerecombinationratecoefficientsaredeterminedfromthecalculationofelementaryvibrationalphoto-ionisationcrosssections.TransitionsbetweenCO~+(X,AandB)andCO(X)areconsidered.Totalphoto-ionisationcrosssectionsandrecombinationcoefficientsarecomputedinthetemperatureinterval500-15000K.
简介:Byemployingaradiofrequency(RF)feedbackchain,theself-interferencecanbecanceledefficientlyinco-timeco-frequencyfullduplex(CCFD).However,theevitablesignalcrosstalkwhichiscausedbytheimperfectRFfeedbackchainisolationusuallydamagestheself-interferencecancelation(SIC)performance.Todealwiththisproblem,firstly,weanalyzetheimpactofRFfeedbackchainisolationonSICperformance.ThenadigitalpreprocessingschemewithRFfeedbackchainisproposedinthemultiple-antennaCCFDarchitecture.Usingbothanalyticalandexperimentalmethods,wefindthattheproposedschemeachievesabetterperformanceonSIC.
简介:利用methoxysilyl一半的水解作用和冷凝作用,器官无机的混血儿(N-isopropylacrylamide-co-acrylamide-co-3-(trimethoxysilyl)propylmethacrylate)poly,P(NIPAM-co-AM-co-TMSPMA)microgels经由二个不同方法被准备。第一个方法是microgels是从crosslinkable的fabricated以后线性P(NIPAM-co-AM-co-TMSPMA)terpolymer在terpolymer的更低的批评答案温度(LCST)上面的水的答案。为第二个方法,microgels被常规表面活化剂直接综合NIPAM,AM,和TMSPMA的免费乳剂copolymerization。结果的P(NIPAM-co-AM-co-TMSPMA)microgels的水动力学直径和稳定性强烈取决于microgel的pH和温度水的答案。microgels的水动力学直径与增加测量温度减少了。microgels的阶段转变温度被发现在34附近吗??
简介:<正>EnChine,plusde500enseignantsdefran?aislangueétrangèredispersésdans150universitésontencharge10,000étudiantsquiapprennentl’anglaiscommepremièrelangueétrangèreetlefran?aiscommesecondelangue.Parmanqued’unprogrammenational,l’enseignementduF.L.E.nepouvaitpasatteindrelaqualitédeceluidel’anglaisrégiparunprogrammenationaldepuis1986.L’anglaisrégiparunprogrammenationald’enseignementduF.L.E.nesouffreaucundélai,nousnoussommesmisàl’oeuvreen1988sousladirectionduComiténationalpourl’Educationetavonsmenénotreentrepriseàtermeen1990.
简介:BasedonthetechniqueforpreparingLaCl3viadirectpyrolysisofrareearthchloridesolution,ajetpyrolysisreactorwasdesignedandtheintra-reactortemperatureandchemicalreactionswerenumericallysimulatedusingcomputationalfluiddynamics(CFD)technique.Theresultsshowthattheflowratevariationatthefuelinletdoesnotlargelyaffectthetemperatureinthereactor,whiletheincreaseinexternalpressureatthematerialinletrapidlydecreasestheaveragetemperature,Venturitemperature,andoutlettemperature.TheCH4andO2insidethereactorarecombustedcompletely,andwhenthematerialinletpressureis\90Pa,theLaCl3isfullypyrogenated.ThecontentsofCO2,La2O3,andHClfluctuateneartheVenturitubeandfinallystabilize.La2O3contentattheoutletisinatop-to-bottomgradient.
简介:Theactivatedaluminaasacatalystcarrierwerewidelyusedinautomotiveexhaustcatalystsunderhightemperature,suchas,petroleumrefiningcatalysts,hydrogenationandhydrodesulfurizationcatalystcarrierinChinaandabroad.γ-Al2O3wasthecatalystcarrierthatwasthemostwidelyusedandthebestcarrierofimprovedspecificsurfacearea.However,theactivationofthecoatingconsistedofγ-Al2O3wereusuallytransformedintoα-Al2O3at800oC,causingincreaseddensity,reducedspecificsurfacearea,andthecollapseresultofporestructure.Whilethetemperaturereached1200oC,activationofcoatingdetachedfromthecarrier,theresistanceofflowinggasincreased,catalyticactivitydecreased.AdditionofLa2O3stabilizedtheγ-Al2O3crystalstructure,whichwouldkeeptheactivationstabilityofcoatingatahightemperatureandinhibitactivityloss.Theactivatedaluminacarriertreatedwiththesolid-pore-expandingagentcontaining[La(EDTA)]-thatsynthesizedusingsolidandsolid-hybridapproachwiththethermalstabilizerlanthanaandEDTAatthehigh-temperaturehada10-30μmlargeporeporousnetwork-likestructure,afteraluminawascalcinedat1200oCfor1h.Thespecificsurfaceareaoffourspecimenwerebeyond120m2/g,whilethesamplespecificsurfaceareaofx([La(EDTA)]-)=1%wasupto150.36m2/g.
简介:由于不同的网络服务的不同特点,确定其对网络的要求也不同,一个网络的性能变化,根据服务运行于它。然而,以往的网络性能评价(NPE)开展基于网络参数的评价,而没有考虑从特定的服务在网络上运行。针对这一问题,提出了一种新的面向服务的NPE框架。首先,在不同类型的服务之间的特性差异进行了研究。其次,开展多种业务的综合评价,增强的低复杂度自适应(LA)-模糊层次分析法(FAHP)介绍;同时采用专家直接构造(ECD)算法的一致性检查后,在以往的研究中可以省略,从而显著降低了专家的计算复杂度和评估工作。然后,根据每个服务的特点,修正了各自的隶属函数,从而使该la-fahp适应各种服务的评价方案。与其他NPE方法证明了它的有效性和所提出的框架的高灵敏度的后续比较和分析,验证了该算法的计算复杂度低以及。
简介:此文作者综合运用修辞学、叙述学、精神分析学及结构主义批评方法分析了著名导演爱森斯坦的著名影片《战舰波将金号》,通过这一实例阐述了有关电影隐喻的多种理论问题。作者指出:一、任何电影画面都是多义的,而且由于明喻的句法标志和语言标志过于繁琐,所以电影中隐喻过程压倒了明喻过程。二、画面的多义性可以通过蒙太奇表现,但也可以通过孤立的画面表现,孤立的画面由于配音而产生隐喻效果。三、蒙太奇式的隐喻过程和孤立画面的隐喻过程在电影中同时存在,它们被电影语法组织起来,而电影语法的基础则是对应。四、不论是类比还是对应都同属于隐喻过程,这种隐喻过程是人类理性思维、政治思维或艺术思维的共同基础。
简介:AseriesofLa2O3/MCnylonnanocompositeswerepreparedviainsitupolymerization.Theeffectsofcontentofnano-La2O3onthemechanicalpropertiesofnanocompositeswerestudied.Dispersionofnano-La2O3inMCnylonmatrixwasobservedwithSEM.ThecrystalstructureofnanocompositeswascharacterizedbymeansofXRD.SEManalysisshowsthatLa2O3nanoparticlesareuniformlydispersedinMCnylonmatrixandlittleclusteringexistswhenthecontentofnano-La2O3islowerthan1%,however,whenthecontentofnano-La2O3ismorethan1%,itbeginstocluster.XRDanalysisindicatsthatnano-La2O3doesnotchangethecrystalstructureofMCnylon.Mechanicalpropertiestestsshowthatthetensilestrength,elongationatbreak,impactstrength,flexuralstrength,andflexuralmodulusofnanocompositesfirstincreasethendecreaseasthecontentofnano-La2O3isincreased.Whenthecontentofnano-La2O3is0.5%,thetensilestrengthandelongationatbreakofnanocompositesreachmaximum,whichare17.9%and52.1%higherrespectivelythanthoseofMCnylon.Whenthecontentofnano-La2O3is1.0%,theimpactstrength,flexuralstrengthandflexuralmodulusofnanocompositesreachmaximum,whichare36.6%,12.7%and16.3%higherrespectivelythanthoseofMCnylon.