简介:Theinfluenceofinitialstrainstateonthedynamicresponseofanendbearingpileembeddedinisotropicsaturatedsoilisinvestigatedthroughthelinearizedtheoryofsmallelasticperturbationsuperposedonlargelystressedbodies.Thegoverningequationsforsoil,basedonBiot’sporoelasticitytheory,arederivedinthecylindricalcoordinates,andthepileismodeledbyusingtheone-dimensionalelastictheory.Theanalyticalsolutionsofpileimpedance,frequencyresponseofbothtwistangleandtimehistoryofvelocityresponseareobtainedbyusingofseparationofvariablestechnique.Finally,aparametricstudyoftheinfluenceofinitialstrainsonthetorsionalimpedance,twistangle,andvelocityresponseatthetopofthepileiscarriedout.
简介:Fora〈r〈b,theapproachofLiandZhou(2014)isadoptedtofindjointLaplacetransformsofoccupationtimesoverintervals(a,r)and(r,b)foratimehomogeneousdiffusionprocessbeforeitfirstexitsfromeitheraorb.Theresultsareexpressedintermsofsolutionstothedifferentialequationsassociatedwiththediffusionsgenerator.Applyingtheseresults,weobtainmoreexplicitex-pressionsonthejointLaplacetransformsofoccupationtimesforBrownianmotionwithdrift,BrownianmotionwithalternatingdriftandskewBrownianmotion,respectively.
简介:ThesynchrodoublepulsesignalmodeisfreuqentlyusedinShortBaseLine(SBL)underwaterpositioningsystemsoastoobtaintheinforma-tionofbothdistanceanddepthofatargetsimultaneously.Howerer,thissignalmodealsobringsaboutrangingindistinctnessresultinginashorterpositioningdistancemuchlessthanthatlimitedbytheperiodofthesynchrosignal.Thispaperpresentsahardwaredistance-gatedataacquiringscheme.Itputstheoriginaldatasenttothecomputerinorderof"directfirstpulse—depthinformationpulse(orfirstpulsereflectedbywatersurface)…"toguaranteetheeffectivepositioningdistanceofthesystem.Ithastheadvan-tageofreducingtheprocessingtimeofthecomputerthusensuringtherealtimefunctioningofthesystem.Afigureoftheorbitofanunderwatermovingtargetmeasuredinpracticeisattachedtotheendofthepaper.
简介:Pre-stackmigrationimaging(PMI)method,whichisusedingeophysicalexplorationbytheperformanceofsinglesidedetectionandvisuallydisplay,canbeusedtoidentifythelocation,orientation,andseverityofdamagesinconcretestructure.Inparticular,thisletterfocusesontheexperimentalstudybyusingafinitenumberofsensorsforfurtherpracticalapplications.Aconcretestructurewithasurface-mountedlinearPZTtransducersarrayisillustrated.Threetypesofdamages,horizontal,dippingandV-sha...
简介:这份报纸面对一个电的偏导领域与内在的有限变丑在软electroactive柱体学习波浪繁殖。为electroelasticity和联系线性增长理论基于一个最近建议的非线性的框架,管理axisymmetric波浪的基本方程在柱体打手势,它受到同类预先拉长并且先存在的轴的电的排水量,当electroactive材料各向同性、不可压缩时,被介绍。准确波浪答案然后被导出以(修改)Bessel函数。为非线性的electroactive材料的一个原型模型,解说性的数字结果被给。这被显示出效果预先拉长并且电的偏导地能在波浪繁殖特征上是重要的。
简介:AdynamicalLangevinmodelisemployedtoevaluatetheexcessoftheneutronemissioninthefissionofheavynuclei~(240)Cf,~(246)Cf,~(254)Cf,~(240)Urelativetothestandardstatistical-modelpredictionatvarioussaddle-to-scissionfrictionstrengths.Itisshownthatwhentheneutron-to-protonratioN/Zofthesystemincreases,thesensitivityoftheexcesstothefrictiondecreasessubstantially,anditalmostdisappearsfor~(240)U.WesuggestthatusingthosecompoundsystemswithlowN/Zfavorsanaccuratedeterminationforthesaddle-to-scissionfrictionstrengthbasedonthemeasurementofthepre-scissionneutronmultiplicity.
简介:预先滑动的政体典型地在机械系统的动态建模被忽视。然而,处于静态的磨擦引起的接触状态的变化可以减少位置的精确性和控制精确。为了调查在接触之间的关系,地位和接触在预先滑动强迫磨擦,一个光试验性的方法在这份报纸被介绍。与这个方法,在透明材料的接口的真实接触状态能被使用处理技术的一幅图象基于光的全部的思考原则观察。新奇安装,包括一双矩形的trapezoidal块,被建议解决精确地把不同正切、正常的力量用于接触接口的挑战性的问题。改进Otsus方法被用于测量。通过在polymethylmethacrylate(PMMA)上执行的试验性的研究,接触粗糙的数量被证明是影响真实接触区域的主导的因素。在在预先滑动的政体的真实接触区域和接触力量之间的关系被学习,并且在接触接口的静态的磨擦的分发是讨论的品质上。真实接触区域与增加静态的磨擦一起在膨胀的新现象被识别。上述的关系在在一个经常的正常压力下面的接触接口是近似线性的,并且磨擦应力的分发从前缘减少到后面的边。
简介:Inthispaper,anewdevelopedmulti-channelpre-processingcircuitforsignalsfromtemperaturesensorwasintroducedinbrief.Thiscircuitwasdevelopedtocollectandamplifythesignalsfromtemperaturesensor.Thisisauniversalcircuit.Itcanbeusedtoprocessthesignalsfromthermocouplesandalsousedtoprocesssignalsfromthermistors.Thiscircuitwasmountedinastandardbox(440W×405D×125Hmm)asaninstrument.The
简介:Carbon-manganesesteelisoftenappliedincomponentsofpipesinnuclearplant.Ultrasonicfatiguetestsfollowinglowcyclefatigue(LCF)cyclesdamagedareusedtostudythestrengthofveryhighcyclefatigure(VHCF).ThecomparisonoftestresultsofsimpleVHCFandcumulativefatigue(LCFplusVHCF)showsthatLCFloadinfluencesthefollowingVHCFstrength.ContinuumdamagemechanicsmodelisextendedtoVHCFregion.TheeffectofLCFloadonVHCFisstudiedbyanimprovedcumulativedamagemodel.
简介:Wepresentthedesignandexperimentofabroadbandopticalparametricchirped-pulseamplifier(OPCPA)whichprovideshighconversionefficiencyandgoodbeamqualityat808nmwavelength.Usingathree-dimensionalspatialandtemporalnumericalmodel,severaldesignconsiderationsnecessarytoachievehighconversionefficiency,goodbeamqualityandgoodoutputstabilityarediscussed.Toimprovetheconversionefficiencyandbroadentheamplifiedsignalbandwidthsimultaneously,thenonlinearcrystallengthandOPCPAparametersareanalyzedandoptimizedwiththeconceptofdissipatingamplifiedidlerbetweenopticalparametricamplification(OPA)oftwocrystalsconfiguration.Intheexperiment,anamplifierconsistingoftwoOPCPAstagesof‘L’typeconfigurationwasdemonstratedbyusingtheoptimizedparameters.Anamplifiedsignalenergyof160mJwasachievedwithatotalpump-to-signalefficiencyof35%(43%efficiencyfortheOPCPAstage2).Theoutputbandwidthofsignalpulsereached80nmandthesignalpulsewascompressedto24fs.Theenergystabilityreached1.67%RMSat3%pumpenergyvariation.TheoptimizedOPCPAamplifieroperatesatarepetitionrateof1Hzandisusedasafront-endinjectionforthemainamplifierofSG-II5PWlaserfacility.
简介:Twograftingmethods,i.e.solutiongraftingandpre-adsorbing,areintroducedtocovalentlyimmobilizehydrophilicpolymersonsegmentedpolyurethane(SPU)tomodifyitshydrophilicityandtoimproveitscellcompatibility.Solutiongraftingresultsinhigherdegreeofgraftingandroughersurfacemorphology.Cellcultureevaluationdemonstratesthatthemodifiedmembranesthusobtainedaredisadvantageoustotheendothelialcell(ECs)growthprobablybecausethehydrophilicgroupsonthesurfaceareover-crowded.However,pre-absorbinggraftinggenerateslowerdegreeofgrafting,whichisdetectedandconfirmedbyATR-FTIRspectraandwatercontactangle.Scanningelectronmicroscopic(SEM)measurementshowsthatthelattermethodproducesaplaneandsmoothmorphology,whichissimilartotheSPUcontrolsamplecontrolled.Whengraftingwithlowermonomerconcentration,ECscouldgrowonSPU-g-PHEA[poly(2-hydroxyethylacrylate)],SPU-g-PAAm(polyacrylamide),SPU-g-PDMA[poly(2-(dimethylamino)ethylmethacrylate)]orquaternizedSPU-g-PDMAsurfacewithelongatedcellshapes.Hence,thecellcompatibilityofSPUisimprovedandausefulmethodtoconstructacellcompatiblelayeronthepolymersurfacehasbeendeveloped.``
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简介:Differentoxygenandnitrogencontainingfunctionalgroupswerecreatedonthesurfaceofthemultiwalledcarbonnanotubes.Themulti-walledcarbonnanotubesweretreatedinultrasonicbathwithsulfuricornitricacid.Furthermorethesurfacetexturewasmodifiedbyincreaseoftheroughness.Inparticularaftertreatmentwiththeoxidizingnitricacid,incomparisontotheH_2SO_4orultra-sonictreatedsamples,cratersandedgesaredominatingthesurfacestructures.Manganeseoxidewasdepositedonthemultiwalledcarbonnanotubesbyprecipitationmechanism.Variousmanganeseoxidesareformedduringthedepositionprocess.Thesampleswerecharacterizedbyelementalanalysis,microscopy,thermalanalysis,Ramanspectroscopy,andbythezetapotentialaswellasX-raydiffractionmeasurements.Itwasshownthatthedepositedmanganeseoxidesarestabilizedratherbysurfacetextureofthemulti-walledcarbonnanotubesthanbycreatedfunctionalgroups.
简介:Thefirstexperimentalmeasurementsofintense(~7×1019Wcm-2)laser-driventerahertz(THz)radiationfromasolidtargetwhichispreheatedbyanintensepulseoflaser-acceleratedprotonsisreported.ThetotalenergyoftheTHzradiationisfoundtodecreasebyapproximatelyafactorof2comparedtoacoldtargetreference.Thisisattributedtoanincreaseinthescalelengthofthepreformedplasma,drivenbyprotonheating,atthefrontsurfaceofthetarget,wheretheTHzradiationisgenerated.TheresultsshowtheimportanceofcontrollingthepreplasmascalelengthforTHzproduction.
简介:Thispaperintroducesajointnonlinearityandchromaticdispersionpre-compensationmethodforcoherentopticalorthogonalfrequency-divisionmultiplexingsystems.Theresearchresultsshowthatthismethodcanreducethewalk-offeffectandcanthereforeequalizethenonlinearimpairmentseffectively.Comparedwiththeonlyotherexistingnonlinearitypre-compensationmethod,thejointnonlinearityandchromaticdispersionpre-compensationmethodisnotonlysuitableforlow-dispersionopticalorthogonalfrequency-divisionmultiplexingsystem,butalsoeffectiveforhigh-dispersionopticalorthogonalfrequency-divisionmultiplexingtransmissionsystemwithhigherinputpowerbutwithoutopticaldispersioncompensation.Thesuggestedsolutiondoesnotincreasecomputationcomplexitycomparedwithonlynonlinearitypre-compensationmethod.For40Gbit/scoherentopticalorthogonalfrequency-divisionmultiplexing20×80kmstandardsingle-modefibresystem,thesuggestedmethodcanimprovethenonlinearthreshold(forQ>10dB)about2.7,1.2and1.0dB,andthemaximumQfactorabout1.2,0.4and0.3dB,for2,8and16ps/(nm·km)dispersioncoefficients.