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简介：Thispaperpresentsthedesignandsimulationofseveralfixed-tunedsub-harmonicmixerscoverfrequenciesfrom110GHto130GHz,215GHto235GHz,310GHto350GHz,and400GHto440GHz.Amongthem,120GHz,225GHz,330GHzsubharmonicmixersaredesignedwithflip-chippedplanarschottkydiodemountedontoasuspendedquartz-basedsubstrate,the225GHzand425GHzsubharmonicmixersareGaAsmembraneintegrated,andthe115GHzsubharmonicmixerhasbeenfabricatedandtestedalready.

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简介：Inordertoreducenursingintensityandimprovefreedomoftheelderlyandthedisabled,amulti-functionnursingwheelchairwhichcanswitchchairtobedandrealizemanykindsofposturetransformationisdesigned.Thispaperintroducesthemechanicalstructuredesign(positionadjustmentmechanismandvariablewheelbasemechanism)andcontroldesignofposturetransformationunitofmultifunctionalnursingwheelchair.

简介：On-orbitservicespacecraftorbitproblemhasbeenaddressedfordecades.Theresearchofon-orbitservicespacecraftorbitcanberoughlydividedintoorbitdesignandorbitoptimization.Thepapermainlyfocusesontheorbitdesignproblem.Wesimplysummarizeofthepreviousworks,andpointoutthemaincontentoftheon-orbitservicespacecraftorbitdesign.Weclassifycurrenton-orbitservicespacecraftorbitdesignproblemintoparking-orbitdesign,maneuvering-orbitdesignandservicing-orbitdesign.Then,wegiveadetaildescriptionofthethreespecificorbits,andputforwardourownideasontheexistedachievements.Thepaperwillprovideameaningfulreferencefortheon-orbitservicespacecraftorbitaldesignresearch.

简介：Forthepurposeofachievinghigh-resolutionoptimalsolutionsthispaperproposesanodaldesignvariablebasedadaptivemethodfortopologyoptimizationofcontinuumstructures.Theanalysismesh-independentdensityfield,interpolatedbythenodaldesignvariablesatagivensetofdensitypoints,isadaptivelyrefined/coarsenedaccordingtoacriterionregardingthegray-scalemeasureoflocalregions.Newdensitypointsareaddedintothegrayregionsandredundantonesareremovedfromtheregionsoccupiedbypurelysolid/voidphasesfordecreasingthenumberofdesignvariables.Apenalizationfactoradaptivitytechniqueisemployedtopreventprematureconvergenceoftheoptimizationiterations.Suchanadaptiveschemenotonlyimprovesthestructuralboundarydescriptionquality,butalsoallowsforsufficientfurthertopologicalevolutionofthestructurallayoutinhigheradaptivitylevelsandthusessentiallyenableshigh-resolutionsolutions.Moreover,comparedwiththecasewithuniformlyandfinelydistributeddensitypoints,theproposedadaptivemethodcanachieveahighernumericalefficiencyoftheoptimizationprocess.

简介：Crashworthinessofcellularmetalswithalineardensitygradientwasanalyzedbyusingcell-basedfiniteelementmodelsandshockmodels.Mechanismsofenergyabsorptionanddeformationofgradedcellularmetalswereexploredbyshockwavepropagationanalysis.Resultsshowthatapositivedensitygradientisagoodchoiceforprotectingtheimpactingobjectbecauseitcanmeetthecrashworthinessrequirementsofhighenergyabsorption,stableimpactresistanceandlowpeakstress.

简介：AnapproachisproposedtorealizeadigitalchannelizedreceiverinthefractionalFourierdomain(FRFD)forsignalinterceptapplications.ThepresentedarchitecturecanbeconsideredasageneralizationofthatinthetraditionalFourierdomain.Sincethelinearfrequencymodulation(LFM)signalhasagoodenergyconcentrationintheFRFD,bychoosinganappropriatefractionalFouriertransform(FRFT)order,thepresentedarchitecturecanconcentratethebroadbandLFMsignalintoonlyonesub-channelandthatwillpreventitfromcrossingseveralsub-channels.Thustheperformanceofthesignaldetectionandparameterestimationafterthesub-channeloutputwillbeimprovedsignificantly.Thecomputationalcomplexityisreducedenormouslyduetotheimplementationofthepolyphasefilterbankdecomposition,thustheproposedarchitecturecanberealizedasefficientlyasintheFourierdomain.Therelatedsimulationresultsarepresentedtoverifythevalidityofthetheoriesandmethodsinvolvedinthispaper.

简介：Digitalcircuitsoperatinginthesub-thresholdregimeconsumetheleastenergy.Thestrictenergyconstraintsaredesiredintheapplicationswhichworkatthelowestpossiblesupplyvoltage.Ontheotherhand,theconventionaldesignflowutilizesthetechnologylibraryprovidedbythefoundrywithafixedvoltageboundary,whichcausesproblemswhenthesupplyscalesdowntothesub-thresholdregime.Inthispaper,wepresentadesignmethodologytocharacterizetheexistingcelllibrarywithLibertyNCXtofacilitatethestandarddesignflow.Itisdemonstratedin0.13mcomplementarymetal-oxide-semiconductor(CMOS)technologywiththesupplyvoltageof300mV.

简介：Withthedevelopmentofcleanenergy,switchinganddistributionissuesinaphotovoltaicsystemaregettingmuchattentioninrecentyears.ThispaperdesignsaDCtoACinverterandpowerswitchinganddistributionsystembetweenasolarpowersystemandthemunicipalsystembyusingtheDarlingtonamplifierstructurewiththephotosensitiveresistorandaccompanyingrelays,anddetailsthesystemcircuits.Theproposedsystemcanachieveastableoutputof110VAC,aswellasself-generatingdrivingvoltageandswitchingbetweenthemunicipalelectricalsystemandthesolarpowersystem.Themathematicanalysisandactuallytestresultsdemonstratethattheproposedmethodisaneasy,inexpensive,andlowcostwaytobuildasolarpowerswitchinganddistributionsystem.

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简介：Thispaperpresentedacontroldesignmethodologyforaprotonexchangemembranefuelcell(PEMFC)generationsystemforresidentialapplications.Thedynamicbehaviorofthegenerationsystemiscomplexinsuchapplications.Acomprehensivecontroldesignisveryimportantforachievingasteadysystemoperationandefficiency.Thecontrolstrategyfora60kWgenerationsystemwasproposedandtestedbasedonthesystemdynamicmodel.Atwo-variablesingleneuronproportional-integral(PI)decouplingcontrollerwasdevelopedforanodepressureandhumiditybyadjustingthehydrogenflowandwaterinjection.Asimilarcontrollerwasdevelopedforcathodepressureandhumiditybyadjustingtheexhaustflowandwaterinjection.Thedesiredoxygenexcessratiowaskeptbyafeedbackcontrollerbasedontheloadcurrent.Anoptimalseekingcontrollerwasusedtotracetheuniqueoptimalpowerpoint.TwonegativefeedbackcontrollerswereusedtoprovideACpowerandasuitablevoltageforresidentialloadsbyapowerconditioningunit.Controlsimulationtestsshowedthat60kWPEMFCgenerationsystemrespondedwellforcomputer-simulatedstepchangesintheloadpowerdemand.Thiscontrolmethodologyfora60kWPEMFCgenerationsystemwouldbeacompetitivesolutionforsystemleveldesignssuchasparameterdesign,performanceanalysis,andonlineoptimization.

简介：Opportunisticarrayradar(OAR)isanewgenerationradarsystembasedonthestealthoftheplatform,whichcanimprovethemodernradarperformanceeffectively.Designingtheorthogonalcodesetswithlowautocorrelationandcross-correlationisakeyissueforOAR.Thispaperproposesanovelhybridgeneticalgorithm(HGA)anddesignsthepolyphaseorthogonalcodesetswithlowautocorrelationandcross-correlationproperties,whichcanbeusedintheOARsystem.Thenovelalgorithmcombineswithsimulatedannealing(SA)andgeneticalgorithm(GA),addsinkeepingbestindividualsandcompetitioninsmallscope,andintroducesgreycorrelationevaluationtoevaluatefitnessfunction.TheseavoidtheprematureconvergenceproblemexistedinGAandenhancetheglobalsearchingcapability.Atlast,thegeneticresultsareoptimizedtoobtainthebestsolutionbyusinggreedyalgorithm.ThesimulationresultsshowthattheproposedalgorithmiseffectiveforthedesignoforthogonalphasesignalsusedinOARsystems.

简介：在上一期（2013年11期）本刊对BlackmagicDesignUltraStudio4K盒子进行了初步测评．从外观工业设计到各种应用接口的介绍，带大家初步认识了这个4K盒子的强大功能．很多读者对4K盒子表现出浓厚的兴趣，尤其对目前最为火热的4K后期环节处理尤为关注。本文从4K后期剪辑角度，UltraStudio4K进行的索尼AX14K摄像机的后期进阶体验。

简介：Anovelcompactelectromagneticbandgap(EBG)structureconstructedbyetchingtworeversesplitrings(RSRs)andinsertinginterleavingedge(IE)onthepatchofconventionalmushroom-likeEBG(CML-EBG)isinvestigated.SimulateddispersiondiagramsshowthattheproposedEBGstructurepresentsa13.6%sizereductioninthecenterfrequencyofthebandgap.TwocomparisonshavebeencarriedoutfortheanalysisoftheeffectoftheRSRsandIEconfiguration.Then,asampleofthisnovelEBGisfabricatedandtested,furtherexperimentaldataagreewellwiththesimulatedresults.Thus,thisEBGstructuremakesagoodcandidatetodecreasemutualcouplingincompactmicrostrippatcharray.

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简介：OneofthekeychallengesforimplementingRFIDsystemsinsupplychainmanagementisthedifficultyineconomicjustification.Suchdifficultyisfurtheramplifiedbyitspublicparticipationnatureasmultipleself-interestbeneficiariesmayreceivediversepaybacks,andtheirincentivestojointhesystemaredifficulttoalign.Thispaperaimstoaddresstheseproblemsbyacollaborativedesignfromtwoaspects.First,weproposetointroduceacentralizedplanningmechanisminthechaintofacilitatetheparticipation,sothatthecostoftheoverallsystemcanbeminimized.Second,weproposetoanalyzethemulti-faceteconomicreturnfrommulti-purposeapplicationstoachievethefullpotentialofRFIDsystems.Toillustrateourapproach,itsapplicationforinventoryinaccuracyandproductrecallinRFIDsystemispresented.

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