简介：Thispaperpresentstheproblemofcontrolofanti-aircraftmissilelaunchermountedonamovingcarrier-vehicle.Directexcitationsonthevehiclefromtheroadcauseadversevibrationsofthelauncher.Inordertoincreasetheprecisionoftheguidingsystemintheconditionsofself-propelledmovementofthesetuponabumpyroad,theadaptivecontrolalgorithmwasproposed.Someresearchresultsofcomputersimulationarepresentedinagraphicalform.

简介：Theeffectsoftwogeometricrefinementstrategieswidespreadinnaturalstructures,chiralityandself-similarhierarchy,onthein-planeelasticresponseoftwo-dimensionalhoneycombswerestudiedsystematically.Simpleclosed-formexpressionswerederivedfortheelasticmoduliofseveralchiral,antichiral,andhierarchicalhoneycombswithhexagonandsquarebasednetworks.Finiteelementanalysiswasemployedtovalidatetheanalyticalestimatesoftheelasticmoduli.Theresultswerealsocomparedwiththenumericalandexperimentaldataavailableintheliterature.WefoundthatintroducingahierarchicalrefinementincreasestheYoung'smodulusofhexagonbasedhoneycombswhiledecreasestheirshearmodulus.Forsquarebasedhoneycombs,hierarchyincreasestheshearmoduluswhiledecreasingtheirYoung'smodulus.IntroducingchiralitywasshowntoalwaysdecreasetheYoung'smodulusandPoisson'sratioofthestructure.However,chiralityremainstheonlyroutetoauxeticity.Inparticular,wefoundthatanti-tetra-chiralstructureswerecapableofsimultaneouslyexhibitinganisotropy,auxeticity,andremarkablylowshearmodulusasthemagnitudeofthechiralityoftheunitcellincreases.

简介：Inthepresentstudy,theconceptoftheoutputfrequencyresponsefunctionisappliedtotheoreticallyinvestigatetheforcetransmissibilityofmulti-degreeoffreedom(MDOF)structureswithanonlinearanti-symmetricviscousdamping.Theresultsrevealthatananti-symmetricnonlinearviscousdampingcansignificantlyreducethetransmissibilityoverallresonanceregionsforMDOFstructureswhileithasalmostnoeffectonthetransmissibilityovernon-resonantandisolationregions.Theresultsindicat...

简介：Thescatteringproblemofanti-planeshearwavesinafunctionallygradedmaterialstripwithanoff-centercrackisinvestigatedbyuseofSchmidtmethod.Thecrackisverticallytotheedgeofthestrip.ByusingtheFouriertransform,theproblemcanbesolvedwiththehelpofapairofdualintegralequationsthattheunknownvariableisthejumpofthedisplacementacrossthecracksurfaces.Tosolvethedualintegralequations,thejumpofthedisplacementacrossthecracksurfaceswasexpandedinaseriesofJacobipolynomials.Numericalexampleswereprovidedtoshowtheeffectsoftheparameterdescribingthefunctionallygradedmaterials,thepositionofthecrackandthefrequencyoftheincidentwavesuponthestressintensityfactorsofthecrack.

简介：Toinvestigatetheinhibitingeffectsoftheanti-angiogenicfactorandostatinandtheanti-angiogenicdrugendostatinontumourangiogenesisandtumourcells,acoupledmathematicalmodeloftumorangiogenesiswithtumourgrowthandbloodperfusionisdeveloped.Simulationresultsshowthatangiostatinandendostatincanimprovetheabnormalmicroenvironmentinsidethetumourtissuebyeffectivelyinhibitingtheprocessoftumorangiogenesisanddecreasingtumourcells.Thepresentmodelcanbeusedasavalidtheoreticalmethodintheinvestigationofthetumouranti-angiogenictherapy.

简介：Thefatiguebehaviorofahighstrengthsteel300Minthegigacycleregimewasinvestigated.Fullyreversedtension-compressionfatiguetestsatambienttemperaturewereperformedusinganultrasonicfatiguesystemoperatingat20kHz.Thestaircasetestmethodwasemployedtoobtainaccuratevaluesofthemeanfatiguestrengthcorrespondingtofixednumbersofcyclesupto10~9.Theseresultswerecomparedtothecurvewhichisestimatedbythedatatestedinthemid-longliferegimeonconventionalservohydraulictestmachineat20Hz.Resultsindicatethatthefatiguestrengthdeterminedfromultrasonicfatiguetestingislightlyhigherthanconventionaltestingintherangeof10~6-10~7cycles.Itisobviousthatnucleationsoffracturestendtooccurbelowthesurface,iffractureshappenaftermorethan10~7cycles.AllthefracturedspecimensfailsfrominternalSiO_2inclusionsorsmallercarbidesandcarbideclusters.

简介：基于Sigma-deltaModulator（Σ△M）原理的数字闭环微机械加速度计不仅实现了力反馈闭环控制,同时直接完成信号的模数转换。基于全差分式电容微加速度设计了一种2-2级联式（MASH）高阶Σ△M闭环系统——MASH_（2-2）,并与传统的单环路二阶、四阶Σ△M闭环系统（SD2、SD4）进行了仿真分析比较,研制了原理样机。微加速度计是基于结构层厚度50mm的SOI硅片通过DRIE刻蚀、气态HF释放等一系列微加工工艺得到,系统电路以数字化方式集成在FPGA中。常压下测试结果表明,样机的灵敏度为0.876V/g,噪声基底为-110dB,零偏不稳定性为20mg,静态温漂为40.8mg/℃,量程为±20g。

简介：实验研究复杂波形结构引起平面界面变形和反射激波冲击下的R-M不稳定性的问题.在竖直激波管中生成稳定的N2/SF6平面界面,激波在圆柱绕射后,冲击平面界面,由此研究复杂激波引起的界面变形.平面激波在圆柱绕射后的流场,演化成具有初始入射波、三波点、弯曲反射波、Mach波和Mach反射产生的滑移线等复杂结构.研究复杂结构激波对界面的作用,对认识界面扰动的生成具有较大帮助.绕柱激波冲击后,平面界面仅在两对滑移线内部发生变形.绕柱激波冲击界面后,两对滑移线将界面分成＂内界面＂和＂外界面＂,界面变形形态同滑移线和界面相交位置相关.反射激波二次冲击下,界面扰动的增长与Jacobs-Sheeley涡量模型较吻合.

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