共查询到20条相似文献,搜索用时 343 毫秒
1.
I.IntroductionApostbeamformernoisecancel1erisasing1e-channeladaptiveprocessorinbeamspace['l.Ithasnotonlysimplerstructure,buta1sobetterpropertiesthane1ementspaceprocessorinimp1ementation.L.C.GodaraandA.Conto1ihavestudiedthesignaltonoiseratioofthebroadbandPIC[1].Theauthorshavesolvedtheprob1emofapplicationconditionsofnarrowbandPIC['],andproposedthatRMGSEFa1gorithmistheoptimuma1gorithminthenarrowbandPICadaptiveprocessing['1.Atpresent,thepfob1emofadaptivecance11ingofbroadbandtowing-shipnoi… 相似文献
2.
QIAN Menglu 《声学学报:英文版》1995,(2)
I.IntroductionNondestructiveeva1uationofstressdistributioninmaterialandmovingor1oadedcompo-nentsisveryimportantinmaterialscienccandengineering.Theultrasonictechnique['l,Ramanspectroscope['l,X-ray['landneutrondiffrac1iontcchnique[4]areusua1lyusedtodetectthestressdistributioninanopaquesample.RecentlytheScanningE1ectronAcousticMicroscopy(SEAM)[s]andphotoacoustictcchniquc[6]havebccnrcportedasncwtechniquetodeterminetheresidualstressdistribution.Itisshownthatthethermalwavealsocanbeusedtomcasure… 相似文献
3.
SupportedbytheNationalNatureScienceFoundationofChina.1.Intr0ducti0nExcimcrlasersareonekindofthemostefficientsourcesofUVcoherentlight.Theyareusedinmanyficldssuchasn2atcrialpr0ccssing[lJ,photolitography['J,laserfusion[3Jetal..Inmany0ftheseapplicationstheshort-x`,avelcngthexcimerlaserswith1aserbeamsofhighqua1ityarenecessary.Mostoftheexci113crlasersi1regcncra11yfedbydischargecircuitswhichpumpthegasvol-umebutcausedischargeinstabiliticsinthedischargevolume['1j.Thislastphenomenonisduetothepresen… 相似文献
4.
QIN Yuwen GE BaozhenCHEN Ximing ZHANG Yimol JIAN Shuisheng 《Chinese Journal of Lasers》1997,6(2):122-130
l.IntroductionJointtransformcorrelation[1]hasbeeninvestigatedwidelyinrecentyears[2~4]be-causeitsreferenceimagesandobjectimagescanbeuPdatedinreal-time[5J.Nonlinearjointtransformcorre1ationtheoretica1ana1ysis[']showsthatcomparedwiththelinearjointtransformcorrelation,non1inearjointtransformcorrelationcanproducemorehighautcacorre1ationPeakintensity,andthelargerPeaktosideloberatiothataregoodforelectronicdevicestodetectandana]yze.Onthebasisofthemodu1ationprincipleana1ysisoftheliq-uidcrysta11ightva… 相似文献
5.
ZHANG Yongkang 《Chinese Journal of Lasers》1997,6(1):81-85
1.IntroductionThewideapplicationsoflaser-inducedshockwaveshadbeendeveloPed,forexam-ple,materialprocessing[1~'J,mediCaltreatment[4],measuring['J,etc.Alltheseinvesti-gationswerestronglyrelatedtotheprofi1eofpressurepulseinducedbythelaserradiationandthePeakpressureonthesurfaceoftargetmaterials.InthisP8Per,theshockpressuremeasurementshavebeenPerformedbyusingaNd-glasslaserwithapulsedurationof5onsasanexcitingbeamandaPVDFtransducerasadetector.2.ExPeriments2.lhoerAhighpowerNd-glass1aserisusedint… 相似文献
6.
Ultrasonic detection of interface in multilayers: Theory and adaptive noise canceling 总被引:1,自引:0,他引:1
《声学学报:英文版》1999,(3)
1IlltroductionIoterfaceevaluationhasbeendiscussedwidely[1-6].ZHANGJPperfomedNDEofinter-faceofmultilayersintheoryanalysis,computersimulationandexPerimentl1l.fuckBaPplieddigitalimageeIiliancementtechniquestotheultrasonicNDEofmateriaIs[2l.ScilaidJstud-iedtheultrasoulcmeasurementmethodsl31.'TatersallHGappliedultrasonicpulsetobondadhesivetesting[4].Themultilayerswithsteelasthefirstlay6risusedinmanyengineeringaPplications.Forexample,oilwellisthemultilayersofsteel,concreteandstratum;solidro… 相似文献
7.
1.IntroductionSqueezedstates0fradiati0nficlds[1avebeenstudicdc0nsiderablyinrecentyears.Besidesthen0rma1lsqueezing,itisals0possibletodefinehigl1pr-ordersqueezings.HongandMan-de1[1Jdefinedthe'2Nth-ordersqueezing,andHillery[2]intr0ducedtheamp1itudesquared.squeezing.Morerecently,Zhangclal.[3JsuggcstedtheamplitudeNth-p0wersqueezingwhichincludosthenorma1squeezingandtheamplitude-squaredsqueezingassPecialcases.Allthese:higher-ordersqueezingshavebeensho`\)ntobeindependentnonclassica1features0f.radi… 相似文献
8.
I.IntroductionWheczesareatypeofabnormallungsoundswhichisclinica11yeqmmon.Althoughwheezesareeasytodistinguishinc1inic,someprob1emsremainunknownsuchastheirmecha-nismofgeneration,theirphysio1ogica1significance['l.AccordingtoForgacs['l,wheezesaregencratedfromthcselfvibrationofairwaywallandarcvividlyanalogizedtothesoundsresu1tedfromtheactionofairflowinthctubeofwindin-strument.Thefrequencyofvibrationisonlyrelatedtotheacousticcharacteristicsoftheairwaywal1,andhasnothingtodowiththevelocityofairflowin… 相似文献
9.
1IntroduCionRecentiytherehasbeenagreatinterestindeVelopingpolymeroPhcalfibersforaPPlicationsinCOInInwhcatiosysterns['],especiallyinlocal..tWorks[']-PoymroPticalfiliersohampadVan8gesoverglasefiberS,suchasnekibilityandalnyecorediameter,whihallOWlowerinStallatiOnandhandingCOS.WhenapPropriaeadditivesareiITtrodUCdintothefibercore,foreXam1e,organicdyemoeculeS,theaPplicatiOnforthesepolyrnerfilierscanbeevenbroaderranginfrOInbocandstOrage.1ernen[31tooPhcalfiberlasersandamghfiers['-'].HoWv… 相似文献
10.
MENG Zhicong ZHANG Guiyan SONG Xiudong JIANG Jianhua LIN Fucheng 《Chinese Journal of Lasers》1997,6(1):91-96
l.IntroductionTheideaofusingahigh-gainactivemediumtoformbrightness-enhancedmicroscofr-.icimageswasproposedmorethan2oyearsago[1:.Introductionofbrightnessamplifierintousua1oPticalsystemwouldPermittoovercomethewellknownrestrictionaccordingtowhichthebrightnessattheoutputoftheopticalsystemcannotexceedthatatthein-put[zJ.SomepulsedmetalvaporlaserssuchasthecopPervaPOrlaser(CVL)havebeenusedasimage-brightnessamplifiersinvariousopticalprojectionsystem[3j-lnthiscase,wecanbenefitfromthattheactivemedium… 相似文献
11.
1.IntroductionSequentia1multisteplaserexcitationhasbeenextensivelyusedtostudydoublyexcit-edstatesofa1ka1ine-earthatoms.Mostoftheinvestig8tionsconcernedthedoublyexcitedstatesinwhichoneofthetwovalenceelectronsishighlyexcitedandtheotherisweaklyexcited[1].Inthecasewhenbothvalenceelectronarehighlyexcited(doubleRydbergstates),onlyafewresultswereobtainedduetothelimitutioninexPerimentaltech-nique['j.ThelimitationarosefromvariousaSpectS.First,duringthesequentiallaserex-citationofdoubleRydbergstatesw… 相似文献
12.
WANG Yaojun 《声学学报:英文版》1994,(3)
I.IntroductionWiththerapiddevelopmentoffiberreinforeedcompositematerials,muchattcntionhasbeenpaidtothecva1uationofthefiber/matrixinterfaces[1-51wheredefectSmayemergeafterlongusageofthecomposites.Foraweakenedinterface,twostiffnessconstantsareusuallyin-tfoducedtomodc1theboundaryconditionsforthestressesanddisNacementsatbothsidesandtheyareclose1yrclatedtotheultrasonicattenuationduetoscattering['].However,sofarnopublishedrcportsarcavai1ab1e.Whitemadeadetailedinvestigationofsoundwavescatteringatac… 相似文献
13.
InPastdecadesseveralformsoflight-inducedscatteringhavebeenobservedfromBaTiossinglecrystali1luminatedbyalinear,polarizedlaserbeam[1~7j.Ingeneral,thescattteringPatterncanbeisotropicoranisotropicdependingonthepropagationdirectionofthelightbomrelativetothecrystallographicaxesandthebeampolarization,itiscom-monlyacceptedthatthephysicaloriginofthisphenomenonistherandomrecordingofParasiticgratingswrittenbyanincidentbeamanditsscatteredbeamfromcrystalinhomo-geneities[1J.Recently,anewtyPeofnonlinearopt… 相似文献
14.
《声学学报:英文版》1997,(4)
I.IntroductionOneoftheimportantfactorsinthepropagationofunderwatersoundinshallowwateristheeffectofinteractionwiththesurfaceandbottom.Inpreviousliterature,thereweremuchdiscussionontherelationshipbetweenmodeattenuationpercycleandreflectionlossinthebottom.KornhauserandRaney[1]usedthesimp1emodelofanisovelocityfluidlayeroveranisove-locityabsorbinghalfspacetoshowatfirstthatfornearhorizontalraystherayandmodeattenuationwereinagreement.Shang[']deducedtherelationshipbetweenthereflectionlossinthebottoma… 相似文献
15.
1.IntroductionInrecentyears,intenselaserphysicshasbecomeanactivefield[1'2].WiththelaserintensityincreasingmanynewPerformanceshaveemerged,suchasabovethresholdion-ization(ATI)[3J,high-orderopticalharmonicemission[4~6Jandstabilizationofatomsinintenselaserfield[7~9J.Uptodate,thelaserint6nsityoflO"W/cm'hasbeenobtained.ItismuchgreaterthantheIimitationoflO"W/cm'forwhichthePerturbativetheoryisva1id.Therefore,nonperturbativemethodshavebeenemployedtodealwiththeintensefieldphysicalproblems.Generall… 相似文献
16.
《核聚变与等离子体物理》2009,29(2)
1. 专著、论文集、学位论文、报告 [序号]主要责任者.文献题名[文献类型标识].出版地:出版者,出版年.起止页码(任选). [1]刘国均,陈绍业,王凤翥,等.图书馆目录[M].北京:高等教育出版社,1957.15-18. [2]辛希孟.信息技术与信息服务国际研讨会论文集:A集[C].北京:中国社会出版社,1994. [3]张筑生.微分半动力系统的不变集[D].北京:北京大学数学系数学研究所,1983. 相似文献
17.
1.IntroductionDuringpastdecades,therehavebeenmanyproposalsforimplementingopticalParallelbinarylogicalprocuring.Thesemethodsmaybedividedintotwocategoriesaccordingtothenonlinearityintheprocessingsteps[1].(i)LinearencodingofinputvariablesandlogicoperationsarePerformedbymeansofnonlinearopticaldevices,suchasSSEEDslz].(n)NonlinearspatialencodingofvariablesandlogicoperationsPerformedbylinearopticalsystems,suchaspolarizationencodinginanimagingsystem['J,spatialcellcodinginashadow-castingsystem[4),t… 相似文献
18.
《声学学报:英文版》1995,(4)
I.IntroductionAsforthedomainoftonesinStandardChinese,Ho.ie[llc1aimedthatthebasiccontoursofStandardChinesetoneswerecocxtcnsiveon1ywiththesyllabicvowe1andanyvoicedsegmentthatmayfollowit.Thisclaimwasbascdontheacousticana1ysisoftheF,curvesinthecita-hontones.Howevcr,ShenandLin[']inapcrceptua1studyontona1coarticu1ationfoundthatinconnectedspeech,fundamentalfrequencyatintertonemiconsetwasperturbed----thisin-cludedinitialvoicedconsonantSandvowels(sy11abicvowe1andnon-sy11abicvowelwerealike)andconclu… 相似文献
19.
ZHONG Guangwu ZHANG Jiquan SONG Xianming LU Jie ZHENG Yinjia ZHANG Guangyang WANG Quanming TANG Nianyi DENG Zhongchao DING Xuantong LIU Yong WANG Enyao 《核聚变与等离子体物理》2003,23(3):161-169
1 IntroductionConfinementandheatingofplasmasareele mentarytopicsinfusionresearch .Tocharacterizethefusionplasmasinauxiliaryheatingexperimentsaswellasinohmicheatingexperiments,measure mentofionenergyinplasmasbecomesnecessary .Neutralparticleanalyzersaresuchdevicesthatareaimedatdirectanalysisofneutralparticlesemittedfromfusionplasmasandareusedinmanyfusionresearchlaboratories[1~ 4] .Detailsofparticledi agnosticprincipleforfusionplasmacanbefoundinReference [5].Emissionofneutralparticlesisintrin… 相似文献
20.
SUN Xiudong ZHOU Zhongxiang ZHAO Hua LI Yanqiu JIANG Yongyuan XU Kebin 《Chinese Journal of Lasers》1997,6(1):71-75
1.IntroductionMutuallypumPedphaseconjugatemirrorsarenonlineardevicesthatsimultaneouslyproducephaseconjugatereplicasoftwomutuallyincoherentbeams.TheyattractedgreatattentionbecauseoftheirnumerousPotentialapplicationsinadaptiveoptics,opticalinfor-mationprocessing,laserlocking,optica1communication,opticalneuralnetwork,andsoon[l~s1.Variousschemesleadingtomutualphaseconjugationhavebeendemonstrated,includingdoub1ephaseconjugatemirror(DPCM)['J,mutua1lyincoherentbeamcou-pler[:J,birdwingphaseconjugat… 相似文献