简介:TheflowofrurallabortourbanisasignificantphenomenoninChinaduringthelast20years.Inspiteofmanyresearchesfocusonthedrivingforceofeconomy,terrainisanimportantindexintheruraldevelopment.Thereisaquestionthatwhethertheflowofrurallaborhassomerelationshipswithterrain.Thestudyusedthereliefdegreeoflandsurface(RDLS)asterrainindex,andthecostdistancemodelandthecenterofgravitymodeltoanalyzetherelationshipbetweenterrainandlaborflows.Theresultsindicated:(1)Inthelast20years,therurallaborforcewasnotsimplyflowingtothelowterrainregioninShaanxiprovince.AndtheRDLSwasconstantlystrengtheningtheinfluenceonthemovement.(2)TheRDLSwaslowinGuanzhongregion,andthetranslationofrurallaborsrelativelywasnotsignificant.SinceNorthShaanxiactastheenergyindustrybase,thenumberofrurallaborsthereincreasedfasterthaninSouthShaanxi.(3)Themovementsofeconomicalcenterstookanimportantroleinthechangeofrurallaborcenters,andterrainfactorsalsoshowedahighcorrelationwiththem.Itisfoundthattheloweroftheterrainindex,thehigherofthelandintensivedegree,themoreintensiveofnonagriculturalizationprocess.
简介:Thispapercontinuesourrecentworkontherelationshipbetweendiscretecontactinteractionsatthemicroscopicscaleandcontinuumcontactinteractionsatthemacroscopicscale(Hulikaletal.,J.Mech.Phys.Solids76,144–161,2015).Thefocusofthisworkisonadhesion.Weshowthatacollectionofalargenumberofdiscreteelementsgovernedbyathreshold-forcebasedmodelatthemicroscopicscalecollectivelygivesrisetocontinuumfracturemechanicsatthemacroscopicscale.Akeystepistheintroductionofanefficientnumericalmethodthatenablesthecomputationofalargenumberofdiscretecontacts.Finally,whilethisworkfocusesonscalinglaws,themethodologyintroducedinthispapercanalsobeusedtostudyroughsurfaceadhesion.
简介:Inthepresentpaper,thegroundreactionforce(GRF)actingonfootinslowsquatwasdeterminedthroughaforcemeasuringsystem,andatthesametime,thekinematicdataofhumansquatwereobtainedbyanalyzingthephotographedimagesequences.Accordingtotheheightandbodyweight,sixhealthyvolunteerswereselected,threemeninonegroupandtheotherthreewomeninanothergroup,andthefundamentalparametersofsubjectswererecorded,includingbodyweight,heightandage,etc.Basedontheanatomycharacteristics,somemarkerswereplacedontherightsideofjoints.Whilethesubjectsquattedatslowspeedontheforceplatform,thegroundreactionforcesontheforefootandheelforeachfootwereobtainedthroughcalibratedforceplatform.Theanalysisresultsshowthatthereactionforceonheelisgreaterthanthatonforefoot,anddoublefeethavenearlyconstantforce.Moreover,fromprocessingandanalyzingthesynchronouslyphotographedimagesequencesinsquat,thekinematicdataofhumansquatwereacquired,includingmainlythecurvesofangle,angularvelocityandangularaccelerationvariedwithtimeforknee,hipandanklejointsinasagittalplane.Theobtainedresultscanofferinstructivereferenceforphotographingandanalyzingthemovementsofhumanbodies,diagnosingsomediseases,andestablishinginthefutureappropriatemathematicalmodelsforthehumanmotion.
简介:摘要:文中主要介绍了VERICUT 9.1软件中FORCE模块的优化方法方式、操作流程及基于该软件生成的优化文件在数控机床上的应用情况。VERICUT软件中FORCE模块根据加工材料、刀具、机床、参数来生成高效的数控程序,不改变原程序的运行轨迹,最终实现节省加工时间,提高生产效率,降低加工成本。
简介:无意剽窃戴望舒先生的诗歌《雨巷》来做自己文章的标题,但正是在读了他的《雨巷》后才知道:原来一条"悠长、悠长,而又寂寥的雨巷"里可以发生这么浪漫的事.可惜我所写的这条雨巷看起来是不太希冀一位"撑着油纸伞,独自彷徨"的怨女出现了,只要不在行走间被突然冲出的吠犬吓得步履踉跄就已算万幸.但无论如何,两条风格迥异的巷都有雨,所以我就姑且把接下来要写的这条称为"半雨巷"吧!