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60 个结果
  • 简介:Walkingwithoutimpactshasbeenconsideredindynamicsasamotion/forcecontrolproblem.Inordertoavoidimpacts,anapproachforboththespecifiedmotionofthebipedanditsgroundreactionforceswaspresentedyieldingacombinedmotionandforcecontrolproblem.Asanapplication,awalkeronahorizontalplanehasbeenconsidered.Inthispaper,itisshownhowthecontrolofthegroundreactionforcesandtheenergyconsumptiondependonthegradientofaslope.Thebipeddynamicsandtheconstraintswithinthebipedsystemandonthegroundarediscussed.Amotioncontrolsynthesisisdevelopedusingtheinversedynamicsprincipleproventobemostefficientforhumanwalkingresearch,too.Theimpactlesswalkingwithcontrolledlegsisillustratedbyaseven-linkbiped.The'flying'bipedhasninedegreesoffreedom,withsixcontrolinputs.Duringlocomotion,thestandingleghasthreescleronomicconstraints,andthetrunkhasthreerheonomicconstraints.However,therearethreerheonomicconstraintsfortheprescribedlegmotionorthreescleronomicconstraintsforreactionforcesofthetrailingleg,respectively.Thenominalcontrolactionforimpactlesswalkingcanbeprecomputedandstored.Themodelproposedallowstheinvestigationofseveralproblems:uphillanddownhillwalking,optimizationofsteplength,stictionofthefeetontheslopeandmanymore.Allthesefindingsarealsoofinterestinbiomechanics.更多还原

  • 标签: 运动和力 控制问题 反作用力 时间无关 动力学原理 应用程序
  • 简介:特别为道路线住所,马来西亚切割斜坡对侵蚀和山崩敏感。这些问题主要由于植被盖子和强壮的腐蚀力量的缺乏发生。另外,地形学因素也成为了影响土壤降级的一个主要因素。因此,这研究针对决定种选择的种的密度的效果,也就是Melastomamalabathricum;一,二,和三棵幼苗每盒子在在在Guthrie走廊高速公路的不同取向(早上和晚上阳光)的选择斜坡的侵蚀率上,Selangor。在六月观察内,有早上阳光斜坡上的三个幼苗/盒子的处理在晚上阳光斜坡上与一样的处理比那些在69.2%显示出更低的侵蚀率。另外,在月六点记录的三棵幼苗(最后的观察)的处理有土壤浸透水平(STL)的最高的减小,在23.6%。而且,种类的生理的价值学习了,在早上阳光斜坡上成年,分别地由12.1%and15.8%(三个幼苗/盒子)以有气孔的传导力和光合的率是更高的。全面结果证明那植物密度是相反地在斜坡上与STL和侵蚀有关评价。在结论,三个幼苗/盒子和早上阳光取向的种的密度在植物上给了积极效果斜坡的生理的性能,减少STL,以及减轻斜坡土壤的侵蚀率。

  • 标签: 土壤侵蚀速率 种植密度 野牡丹 坡向 生理表现 STL
  • 简介:自从环境能力并且象陆地实际上联系了的居民一样可耕全部的平衡,斜坡为各种各样的工程构造正在成为越来越重要的选择。因为斜坡的地质的复杂性,设计和基于斜坡的设计的决策仍然不是实际的完全依靠理论分析和数字计算,但是主要在专家的经验上。因此,它有重要实际意义把一些成功的经验变成数学方程。在在云南设计构造盒子的丰富的典型斜坡之上基于,西南的中国,为分析斜坡稳定性的3个方法在这篇论文被开发了。首先,为分析斜坡稳定性的通信类似的数学方程通过案例研究被建立了。然后,当7个主要影响因素被采用时,人工的神经网络和multivariate回归分析也被建立了。

  • 标签: 斜坡稳定性 地质工程 多元衰退分析 人造神经网络
  • 简介:Thispaperinvestigatesthedifferencesthatresultfromapplyingdifferentapproachestouncertaintymodelingandreportsanexperimentalexaminingerrorestimationandpropagationinelevationandslope,withthelatterderivedfromtheformer.Itisconfirmedthatsignificantdifferencesexistbetweenuncertaintydescriptors,andpropagationofuncertaintytoendproductsisimmenselyaffectedbythespecificationofsourceuncertainty.

  • 标签: DEMS 数字高程模型 斜面模型 误差 测绘工作
  • 简介:Basedonmeteorological,hydrological,forest,andgrasslanddatacollectedbylocationobservation,remotesensing,fieldsurveysandrelevantliteratureduring1956to2009,theecologicalenvironmentchangeinnorthernslopeoftheQilianshanMountainswasanalyzedsyntheticallyusingregressionandcorrelationanalyses.Theresultsshowedthatthetemperaturehadanannualvariationrateof0.0334℃·a-1innorthernslopeoftheQilianshanMountainssince1960,andexhibitedaraisingtrend,especiallysince1987.Theannualvariationrateofannualprecipitationwas0.5702mm·a-1,indicatingthattheprecipitationtendedtoincrease.Theclimatehadchangedfromaridtohumidinthisregionsince1976.From1956to2006,theglacierareaofsixinlandriverbasin(Shiyangheriver,Heiheriver,Beidaheriver,Shuleheriver,DangheriverandHalternheriver)andDatongheriverbasininnorthernslopeofQilianshanmountainsdecreasedby17.7%.Thicknessoftheglacierreducedabout5-20m,andthesnowlineroseabout100-140m.TheGlaciericereservesininlandriverbasinofHexidecreasedby11.4%.From1972to2007,27glaciersintheeasternsectionoftheQilianshanMountainsdisappeared.From1956to2009,therunoffchangeinthenorthernslopeoftheQilianshanMountainswasdifferentindifferentregions.TherunoffwasreducedsignificantlyinShiyangheriverbasin,increasedslightlyinHeiheriverbasin,andincreasedobviouslyinShuleheriverbasin.From1958to1988,theareaofdeforestationandfarmingwasmorethan10.0millionha,andtheforestareawasreduced0.6millionha.SincetheQilianshanMountainNatureReservewasestablishedin1989,theforestwasrestoringgraduallybecauseofcontinualprotectionandcultivating,andtheforestareawasincreased9.4millionhafrom1989to2008.Duetohumaninterference,especiallyover-grazingimpact,thequalityofthewood-land,shrub-landandgrass-landinnorthernslopeoftheQilianshanMountainswereinadegradedcondition,whichre

  • 标签: northern SLOPE of Qilianshan MOUNTAINS ECOLOGICAL
  • 简介:Theeffectsofstabilizingpilesonthestabilityofanembankmentslopeareanalyzedbynumericalsimulation.Theshearstrengthreductionmethodisusedfortheanalysis,andthesoil-pileinteractionissimulatedwithzero-thicknesselasto-plasticinterfaceelements.Effectsofpilespacingandpilepositiononthesafetyfactorofslopeandthebehaviorofpilesundertheseconditionsaregiven.Thenumericalanalysisindicatesthatthepositionsofthepilehavesignificantinfluenceonthestabilityoftheslope,andthepileneedstobeinstalledinthemiddleoftheslopeformaximumsafetyfactors.Intheend,thesoilarchingeffectcloselyassociatedwiththespacebetweenstabilizingpilesisanalyzed.Theresultsarehelpfulfordesignandconstructionofstabilizingpiles.

  • 标签: 路堤边坡 桩基加固 抗滑桩 稳定性 数值分析
  • 简介:Inthiswork,westudiedthedimensionsofstreamtubeintheverticalaswellasinclinedbankconditions.Datawerecollectedfrombothaphysicalmodelanda3-Dnumericalmodel(SSIIM2).Equationsforpredictingstreamtubedimensionswerepresentedandcomparedwithexistingformulae.Incomparisonwithverticalbank,itisfoundthatincliningbankcausesthebottomstreamtubewidthtobegreaterthanatthesurface.Thestrengthofsecondarycurrentformedattheentranceofbranchchannelisreduced.Thesechangesinflowpatterncanreducetheamountofsedimentdeliveryintotheintake.

  • 标签: 流动模式 取水口 河流 岸坡 三维数字模型 尺寸方程
  • 简介:实验与1.5m和四个不同斜坡的经常的长度在一个2-dimentional水池上被执行。速度,雷纳兹压力和骚乱紧张的分布在这份报纸被学习了。结果证明当流动在出口斜坡上面继续,流动速度在隧道床附近增加,减少接近水表面。流动分离没被副词在床形式的冠观察。另外,分离地区的长度与增加入口和出口斜坡增加。最大值使正常化的最大的斜坡角度原因砍应力。基于实验,雷纳兹的形状强调分发通常依赖于入口和水池的出口斜坡,这被结束。另外,雷纳兹压力分发的形状被速度并且加速流动影响。随斜坡角度的增加,另外,第二等的水流被开发并且变得更稳定。在流动和床形式之间的动量主要被转由的象限分析表演的结果扫并且喷射事件。

  • 标签: 湍流强度 坡度 人工 应力分布 分布规律 二次电流
  • 简介:RillerosionisadominantprocessofmorphologicalevolutionoftheLoessPlateauinChina,anddeliveriesmuchloesssedimenttorivers.Datafromtwoflumeexperimentsconductedonthebareandglass-coveredbedsindicatedthatthefillflowdevelopsintoaseriesofrollingwaves.Theshearstressontherillbeddistributesunevenlybothspatiallyandtemporally.Anewmethodbasedontheenergyconservationlawisproposedinthisstudy.Thustherelationshipbetweentherunoffenergyconsumptionfromtheinteractionofwaterflowandslopebedandsoildetachmentisformulated.Theresultsshowedthatthedataforthesoildetachmentrateonslope(Dr)andtheenergyconsumptionofrunoff(E1)fittedwellwithnewly-developedfunction.Therillerosionoccurswhentherunoffenergyconsumptionexceedsacriticalvalue.

  • 标签: Soil DETACHMENT rate RILL erosion RUNOFF
  • 简介:-Generallythetoeofthebankslopeinfrontofthepile-supportedpierhastobedredgedtomeettherequirementsofwaterdepthfortheberthofships,whilethetopoftheslopeinrearofthepiermustbebackfilledandelevatedtomakeconnectionswithlandtransportation.Thenthenaturalstateofequilibriumoftheslopeisdestroyed,andsomedeformationanddisplacementareunavoidablyinducedinthesoilmasswhichwillexertanundesirableinfluenceonthepilefoundationofthepier.Thisisatypicalproblemoftheinteractionbetweentheso-called"passivepile"andsurroundingsoil,andhasbeenscarcelystudiedintheliteratureofgeotechnicalengineering.Inthispaper,fieldobservation,modeltestsandnumericalanalysisconductedbytheauthorstostudytheinteractionbetweenpile-supportedpierandbankslopearebrieflydescribedandsomepreliminaryresultsarepresented.

  • 标签: INTERACTION PASSIVE PILE PIER SLOPE
  • 简介:Recentandpaleo-submarinelandslidesarewidelydistributedwithinstrataindeep-waterareasalongcontinentalslopes,uplifts,andcarbonateplatformsonthenorthcontinentalmarginoftheSouthChinaSea(SCS).Inthispaper,high-resolution3Dseismicdataandmultibeamdatabasedonseismicsedimentologyandgeomorphologyareemployedtoassistinidentifyingsubmarinelandslides.Inaddition,depositionmodelsareproposedthatarebasedonspecificgeologicalstructuresandfeatures,andwhichillustratethelocalstressfieldoverentiresubmarinelandslidesindeep-waterareasoftheSCS.TheSCSisoneofthelargestfluvialsedimentsinksinenclosedorsemi-enclosedmarginalseasworldwide.Itthereforeprovidesasetofpreconditionsfortheformationofsubmarinelandslides,includingrapidsedimentaccumulation,formationofgashydrates,andfluidoverpressure.Anewconceptinvolvingtemporalandspatialanalysesistestedtoconstructarelationshipbetweensubmarinelandslidesanddifferenttimescaletriggermechanisms,andthreemechanismsarediscussedinthecontextofspatialscaleandtemporalfrequency:evolutionofslopegradientandoverpressure,globalenvironmentalchanges,andtectonicevents.Submarinelandslidesthataretriggeredbytectoniceventsarethelargestbutoccurlessfrequently,whilesubmarinelandslidestriggeredbythecombinationofslopegradientandoverpressureevolutionarethesmallestbutmostfrequentlyoccurringevents.Insummary,analysisshowsthattheformationofsubmarinelandslidesisacomplexprocessinvolvingtheoperationofdifferentfactorsonvarioustimescales.

  • 标签: SOUTH China Sea SUBMARINE LANDSLIDES SEISMIC
  • 简介:Anempiricalformulaforestimatingtheovertoppingdischargeofwind-wavesonasmooth-impermeable-simpleslopedykeisderivedthroughmodeltestsinthispaper,itcanbeadoptedbyrelateddesigndepartmentsinthedeterminationofthecrestelevationofthedyke.

  • 标签: OVERTOPPING DISCHARGE design WAVE check WAVE
  • 简介:Themild-slopeequationisfamiliartocoastalengineersasitcaneffectivelydescribewavepropagationinnearshoreregions.However,itscomputationalmethodinCartesiancoordinatesoftenrendersthemodelinaccurateinareaswithirregularshorelines,suchasestuariesandharbors.Basedonthehyperbolicmild-slopeequationinCartesiancoordinates,thenumericalmodelinorthogonalcurvilinearcoordinatesisdeveloped.ThetransformedmodelisdiscretizedbythefinitedifferencemethodandsolvedbytheADImethodwithspace-staggeredgrids.Thenumericalpredictionsincurvilinearcoordinatesshowgoodagreementwiththedataobtainedinthreetypicalphysicalexperiments,whichdemonstratesthatthepresentmodelcanbeusedtosimulatewavepropagation,fornormalincidenceandobliqueincidence,indomainswithcomplicatedtopographyandboundaryconditions.

  • 标签: 正交曲线坐标系 缓坡方程 数值模拟 双曲型 直角坐标系 数值模型
  • 简介:这份报纸考虑在一个温和斜坡(1:40)上宣传的不规则的波浪的非线性的转变。不规则的波浪的二个盒子,机械地基于JONSWAP系列被产生,被用于这个目的。结果显示波浪高度服从瑞利分发在近海地点;在变浅的区域,然而,最大的波浪的高度被理论分布低估。在波浪地区,波浪高度能被合成Weibull分发接近。另外,在不规则的波浪以内联合的非线性的阶段被基于小浪的bicoherence调查。bicoherence系列思考参予联合的阶段的频率模式的数字与减少的水深度增加,,,这做阶段联合的度。在早期的碎以后,尽管阶段联合的度减少,很多更高的泛音波浪模式也涉及非线性的相互作用。而且,加的bicoherence显示与最强壮的本地非线性的相互作用有关的频率模式与减少的水深度变到更高的泛音。

  • 标签: 非线性变换 缓坡 非线性相位耦合 非线性相互作用 WEIBULL分布 相干性分析
  • 简介:Theconventionalpseudo-staticapproachoftenneglectstheeffectoftheverticalseismicaccelerationonthestabilityofaslope,butsomeanalysesunderplane-strain(2D)conditionsshowasignificanteffectontheslopestability.Thepurposeofthisstudyistoinvestigatetheeffectoftheverticalaccelerationonthesafetyofthree-dimensional(3D)slopes.Inthestrictframeworkoflimitanalysis,a3Dkinematicallyadmissiblerotationalfailuremechanismisadoptedherefor3Dhomogeneousslopesinfrictional/cohesivesoils.Asetofstabilitychartsispresentedinawiderangeofparametersfor3Dslopesundercombinedhorizontalandverticalseismicloadingconditions.Accountingfortheeffectsoftheverticalseismicacceleration,thedifferenceinsafetyfactorsfor3Dslopescanexceed10%,whichwillsignificantlyoverestimatethesafetyofthe3Dslopes.

  • 标签: 边坡稳定性 三维运动学 地震加速度 垂直加速度 拟静力法 平面应变