简介：Thetime-domainequalizerofADSLChannelplaysanimportantroleinwholereceivingprocesstohighspeedbitstreams.Inthispaper,anovelADSLchannelequalizationmethodbasedonevolutionaryalgorithmisproposed,inwhichweestablishtheequalizerthroughthemethodofchannelidentification.Theproposedmethodiscapableofsimultaneouslyevolvingbothcoefficientsandtheranksoftheequalizerandthereforeitcanbeappliedtodifferentcharacteristicsofloops.Experimentalresultsshowourmethodhasbetterperformance(shortsearchtimeandhighmodelingprecision).

简介：稳定河槽几何学在相当很长时间吸引了水力的工程师的注意。各种各样的标准被建议了解释一条隧道的自我形成的几何学。基于流动系统，和使用的几何编程的最佳的费用结构，现在的调查提出客观功能产出Lacey的稳定河槽尺寸。功能可能是有用的披露稳定河槽几何学的许多详情。

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简介：Anewall-opticaldemultiplexerbasedonnonlineareffectinsemiconductorlaseramplifier(SLA)isproposed.ItcandemultiplexallchannelsoftheOTDMsignalconcurrently.anditcanalsobeintegratedonasinglechip.TheproposeddeviceconsistsofaseriesshortFabry-Perotamplifiers(FPSLA)settingonthepathverticsally,throughwhichthepreamplifiedopticalsignaltravels.Perpendicularlytothesignal,K(channelnumber)paralleledbeamsoflightpulse,whichactasprobeswithrepetitionatthebitrateofonechannel,irradiateontheseFP-SLAs,respectively,justwhenthecorrespondingsignalchannelpulsepassesthroughtheactiveregionfromlateralside.Thetransmissivitydependsonthesignalpulse.Theoreticalanalysishasbeengiven.Asademonstratingexample,Adeviceoperatedatthespeedof25Gbit/s(2.5Gbit/s×10)issimulatedandtheresultsshowthattheabout9.24dBextinctionratiocanbeachievedeasily.

简介：Responseofadaptivematchedfilter,alsocalledadaptivecorrelator,tomultipathchannelisdiscussedinthispaper.Ithasbeenprovedthatthenewtypeprocessorcanbettermatchwithmultipathchan-nel.Theresultsofexperimentcarriedoutonlakeandinlaboratoryarepresented.Itshowsthattheprocessorhasgooddetectingperformanceintimedomain.

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简介：ThispaperdescribesafullchannelTVmodulatorforallTVsystems,whichhasbeendevelopedsuccessfully.ItemploysadvancedtechniquesuchasPLLfrequencysynthesizerwithmicrowaveintegratedcircuit,andwidebandmicrostripVCOanddigital-analogcombinedintegratedcircuits.Thekeytechniqueofthemodulatorissettledsuccessfully.AllthespecificationsofthemodulatoragreewithTechnicalStandardofChina,whicharetestedbytheauthorityofChina.

简介：Basedontheperiodicstructureofcodeworksoflinearblockcodes,anewideaoflength-varyingcodingdigitalcommunicationssystemisproposedtosavethechannel.Itisshown,byexample,thatupto1/3ofchannelcapacitycanbesavedbythenewsysteminsomespecialsituations.Inordertofindwhichblockcodeissuitabletouseinlength-varyingcodingsystem,theperioddistributionofthecodehastobecal-culated.Newrwsultsabouttheperioddistributionarepresentedwhilemanyopenproblemsremain.

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简介：Thispaperpresentstheexperimentalresultsonthedistributionofsedimentsatchannelbifurcation.Theexperimentshavebeenconductedinaphysicalmodelofchannelbifurcation.Itconsistsofastraightmainchannelwhichbifurcatesintotwobranchchannelsofdifferentwidths.Thetestrigisamobilebedwithfixedbank.Fourdifferentnoseshavebeenusedtostudythephenomenon.Foreachnose,threeupstreamdischargesviz.20l/s,30l/sand40l/shavebeenemployed.Fromthemeasureddata,dischargesandsedimenttransportratiosperunitwidtharecalculatedinthedownstreambranches.Thesedatahavebeensettothegeneralnodalpointrelationandasetofequationshasbeendevelopedtodescribethedistributionofsedimentstothedownstreambranchesfordifferentnoseangles.

简介：Innormalfluvialprocessestheriverchannelisdeterminedbyriverflowswhilethemovementofriverflowsiscontainedbyriverchannels.Therelationshipbetweentherivermorphologyanditsbendcurvatureshowsthatriverswithlargebendcurvaturesalwayshavenarrowanddeepchannelsandthosewithshallowandwidechannelsarealwaysstraight.Theplanformofariverreachesisdeterminedbythecross-sectionalmorphology.Ameanderingriverreachmaybedevelopedundervariouswater-sedimentconditionsaslongasthenarrowanddeepchannelsareformed.

简介：Thesum-ratecapacityofCDMAandTDMAinvectorbroadcastchannelisresearched.Anupperboundofsum-ratecapacityinCDMAsystemandalowerboundofsum-ratecapacityinTDMAsystemarederivedrespectively.Accordingtothesetwobounds,theratioofthetwoboundsatmostcanachievemin(M,K).HereMistheantennanumberofthetransmitterandKisthenumberoftheuserinthisvectorbroadcastchannel.

简介：大木质的碎片和木质的植被能对隧道水力学和形态学施加主要影响，在特别地更小(<30m宽)溪流。尽管碎片和植被长被用于河槽冲刷和沉积控制，为设计者的科学地基于的指南是少见的。最近

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简介：Theoreticalandexperimentalinvestigationsofheattransferinflatcurvilinearchannelhavebeencarriedout.Linearandnon-lineareffectsofDeanvortexesonintensityofheattransferweretakenintoaccount.Thelineareffect,whichdescribeharmonic(sinuous)variationoftheheattransfercoefficientneartheconcavesurfaceofthechannelandthenon-lineareffectcausesthegeneralincreaseoftheheattransfercoefficientduetoaugmentationofheattransferengenderedbytheDeanvortexes.Forbotheffects,mathematicalrelationswereobtainedintheformofquadratures.Thesenumericalresultsweremodifiedtotheformconvenientinengineeringcalculations.TheinvestigationshaveshownthatbothlinearandnonlinearcomponentsgrowupwiththeDeannumber.NonlinearcomponentQ0Tincreasesmoreabruptly,whilethelinearoneQ1Tismoreconservative.Thisisaconfirmationofstabilityofvortexstructures.

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简介：-BasedonthefeasibilitystudyofdevelopingthenavigationresourcesoftheGuanheRiverandthemodeltestresultsofthemouthbarregulation,thispaperpresentssomebasicprinciplesfortheregulationofthechannelonthemouthbar,forinstance,thedirectionofnavigationchannelshouldbeidenticalwiththatoftheebbtidecurrentandthemainwaves,andperpendiculartothebathymetriccontours.Theprinciplesforregulatingmouthbarsarealsodiscussedinthispaper.

简介：Amulti-channelACpowerSupplycontrolerdevelopedrecentlybyuswasintrodueedbrieftyinthispaper.Thiscontrollerisacomputercontrolledmulti-electronic-switchdevice.Thecontrollercontains16independentchannelsinastandardbox(440W×405D×125Hmm).Thereisanelectronicswitchineachchannel,theratedloadpoweris≤1kW.Themainfunctionofthecontrolleristosetthestateofelectronicswitch(ON/OFF)

简介：Tostudythepossibilityofdetectingthecrossingchannelbyusingatraditionalloggingtool,acousticfieldgeneratedbyamonopolesourceinacasedwellwithacrossingchannelofvariousanglesissimulatedby2.5-DFiniteDifferenceMethod(FDM).Snapshotsofnormalstressandsynthetictime-domainwaveformsaredisplayed.Thetwo-dimensionalspectruminwave-numberandfrequencydomainsisalsocalculated,wheretheinfluenceofthechannelisclearerthanthatinthewaveforms.Numericalstudydemonstratedthatacrossingchannelcanbedetectedandsizedifitsangleisgreaterthan30degree,andlargerspacingandlowerfrequencysourcearefavorabletodetectandsizethecrossingchannel.

简介：ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.