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INTRODUCTIONAnAdeno associatedvirus(AAV)particleiscomposedofthreestructuralproteinsandalin ear ,single strandedDNA (ssDNA)genomeofapproximately 4 .7kb .AAVisadefectivehu manparvovirusthatnormallyreplicatesproduc tivelyonlyinthepresenceofhelperfunctionsprovide… 相似文献
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INTRODUCTIONRibozymewasfirstdescribedbyCechandAltmanin 1 981 .ThisformofRNAhadhighlyspecificendonucleaseactivitiestoRNA (Krugeretal.,1 982 ) .Ribozymeshavethreestructures:hammerhead ,hairpinandaxeribozymes.Amongthem ,thehammerheadribozymehasasimplersecondarystruc… 相似文献
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浅议计算机辅助教学 总被引:1,自引:0,他引:1
孔文 《山东教育学院学报》2002,17(6):86-88
ComputerAssistedlnstruction (CAI)isthetermusedtodescribecomputerprogramsdesignedforteaching .ItisimportantnottoconfusethistermwithCALL(ComputerAssistedLanguageLearning)———thecatchalltermfordiffer entformsofL2instructionaccomplishedwiththeuseofcomputers.Fo… 相似文献
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OBSTACLE DETECTION BY ALV USING TWO 2D LASER RANGE FINDERS 总被引:6,自引:0,他引:6
INTRODUCTIONObstacleavoidanceisanessentialtaskoftheALV .Toachievethis,aquickandreliablede tectionofobstaclesisveryimportant.Severalclassesofactivesensorscanbeusedforthispur pose .Alaserrangefinder (LRF)cansuitablybeusedtodetectobstaclesaheadoftheALV .3DLRFs… 相似文献
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ThevarietyofEnglishspokenintheUSAiscalledAmericanEnglish .AmericanEnglishgrewoutofBritishEnglishofthe 17thcentury.WiththefurthergrowthoftheUnitedStates,AmericanEnglishhasevolvedfroma“colonialbranch”toavariantorna tionalstandardofEnglish .Thecharacteristic… 相似文献
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TomwasfollowingUncleSamtotherainforestinBrazil’sAmazonregion①.AshewalkeddeepinsidetherainforestwithUncleSam ,hesawthetreetopstoucheachother,creatingashaded②forestinside .Allofasudden ,Tomheardtheraindropspatting③onthetreeleaves.Tomputonhisraincoatassoona… 相似文献
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贺国强 《上海大学学报(英文版)》2000,4(2)
1 Introduction LetX ,YbetwoHilbertspacesandletAbeaboundedlinearoperator,i.e .,A∈B(X ,Y) .Consid ertheoperatorequationAx=y . (1)IfR(A) ,therangeofA ,isnonclosedinY ,Eq .(1)isill posed[1] .Manyimportantproblemsinappliedsci encesresultinthiskindofequations[2 ,3] .Inthispaperwec… 相似文献
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从一个例子谈起 已知△ABC的三个内角A、B、C满足 :A C =2B ,secA secC =- 2secB ,求cos A -C2 的值 .解 由A C =2B ,得A C =12 0° ,B =6 0° .∵ secA secC =- 2secB ,∴ cosA cosC =- 2 2cosAcosC ,2cos A C2 cos A -C2=- 2〔2cos2 A -C2 - 1 cos(A C)〕 ,即 4 2cos2 A -C2 2cos A -C2 - 32 =0 .因 - 324 <- 1,故解得cos A -C2 =22 .1 关于解题思维表现的分析上例中 ,条件是三角形三内角的一个关系式和有关这些角的一… 相似文献
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NTRODUCTIONAftermuchresearchandsomesuccessfulap plicationsofArtificialNeuralNetwork (ANN)tocontrolsystems,ANNhasbecomeoneoftheim portanttoolstoshowtheintelligenceofthehu manbrain .SinceANNcanbeusedtodescribeanynonlinearcontinuousfunction ,ithasdrawnmuchat… 相似文献
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1 —Whichofthetwotieswillyoutake ?—I’lltake ,forachangesome times.A .either B .both C .neither D .all2 .Thepolicecouldn’tseewhichthecarwent.A .path B .way C .street D .road3.Thebusdriverwasbadlyinbothlegsinthetrafficaccident.A .damaged B .woundedC .injuredD .destroye… 相似文献
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INTRODUCTIONItiswellknownthatinfreeradicalpolymerization,thediffusioncontrolledprocessesstronglyinfluencetherateofpolymerizationandthepropertiesoftheproducedpolymer.Anumberofmodelsweredevelopedtodescribethisphenomenaquantitatively(Achiliasetal.,1988;Achil… 相似文献
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INTRODUCTIONAntisenseoligodeoxynucleotides (ASODN )caninhibittranscriptionandinterferewithspe cialgeneexpression .AfixedpointontheK rasgenewithhighmutationrateinpancreaticcarci nomaoffersanintracellulartargetforpancreaticcarcinomagenetherapywithASODN (Cai… 相似文献
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AlthoughmydearbrotherFrankisalreadyeight 1 .yearsold ,hetriestobehaveasifheisolder.Heis 2 .rathershort,andhasblackhair.Ibringhimtoschool 3.everymorning .Anditiseasytopickouthimfromthe 4.crowdwhileIgoandfetchhimafterschool.Hewears 5 .hishairwildlyandoftenhashisbut… 相似文献
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1 Introduction LetX ,YbetwoHilbertspacesandletA∈B(X ,Y) ,i .e .,aboundedlinearoperator .ConsidertheoperatorequationAx =y (1.1)IfR(A) ,i .e .,therangeofA ,isnon closedinY ,Eq .(1.1)isill posed[1] .Manyimportantproblemsinappliedsciences ,especiallyinverseproblems ,resultinthiski… 相似文献
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INTRODUCTIONTocopewiththemoreandmoreserioushar monicproblemsmainlycausedbypowerelec tronicequipmentapplication ,variouskindsofactivefiltershavebeenproposedandputintofieldapplicationsrecently.Amongthem ,aSeri alHybridActivePowerFilter (SHAPF)asshowninFig.1 (… 相似文献
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朱宣东 《内蒙古师范大学学报(哲学社会科学版)》2001,(Z1)
IntroductionMostofustakeitfor grantedthatunderstandinganutterancemeansthecomprehensionofthetotalmeaningconveyedbythespeaker.Asamatteroffact,itusuallyturnsoutthatitisfarfromenoughforustounderstandandinterpretthemeaningfullyandcorrectly .AnEnglishwordusu… 相似文献
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《上海大学学报(英文版)》2000,(4)
1 Introduction Withthedevelopmentofthe powerelectronicstechnology ,stationarypowerconvertingdevicessuchasAC DCconvertersandDC ACinvertersareappliedinvariousindustrialareas .However ,thishasledtosomeproblems ,e .g .theincreaseofharmonicsinpowersupply ,andtheEM… 相似文献
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1 Introduction Itiswellknownthatmetalhydridesareanidealmediumforhydrogenstorageduetotheirhighdensityandhigh purityofhydrogen .However ,allknownconventionalmetalhydrides ,includingintermetalliccompoundsAB5,AB2 ,andAB ,havereversiblegravi metricH densitiesnomo… 相似文献
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ISTHENOVELDEAD ?Therehasbeennolackofpropheciesofthedeathofthenovelsincethebeginningofthe2 0thcentury .Manyprestigiouscritics,suchasT .S .Eliot,OrtegaY .Gasset,AlbertoMoraviaandCyrilConnolly ,haverelentlesslypronounceddeathsentenceonthenovel.Althoughthousandso… 相似文献