简介:Background:Athleteshavebeenshowntoexhibitbetterbalancecomparedtonon-athletes(NON).However,fewstudieshaveinvestigatedhowthesurfaceonwhichathletestrainaffectsthestrategiesadoptedtomaintainbalance.Twodistinctathletegroupswhoexperiencedifferenttypesofsport-specificbalancetrainingarestablesurfaceathletes(SSA)suchasbasketballplayersandthosewhotrainonunstablesurfaces(USA)suchassurfers.ThepurposeofthisstudywastoinvestigatetheeffectsoftrainingsurfaceondynamicbalanceinathletescomparedtoNON.Methods:EightNON,eightSSA,andeightUSAperformedfive20-strialsineachoffiveexperimentalconditionsincludingastaticconditionandfourdynamicconditionsinwhichthesupportsurfacetranslatedintheanteroposterior(AP)ormediolateral(ML)planesusingpositiveornegativefeedbackparadigms.Approximateentropy(ApEn)androotmeansquaredistance(RMS)ofthecenterofpressure(CoP)werecalculatedfortheAPandMLdirections.Four3×5(group×condition)repeatedmeasuresANOVAswereusedtodeterminesignificanteffectsofgroupandconditiononvariablesofinterest.Results:USAexhibitedsmallerApEnvaluesthanSSAintheAPsignalswhilenosignificantdifferenceswereobservedintheMLCoPsignals.Generally,thenegativefeedbackconditionswereassociatedwithsignificantlygreaterRMSvaluesthanthepositivefeedbackconditions.Conclusion:USAexhibituniqueposturalstrategiescomparedtoSSA.Theseuniquestrategiesseeminglyexhibitadirection-specificattributeandmaybeassociatedwithdivergentmotorcontrolstrategies.
简介:Fatiguecuttingisanewapproachforseparatingmaterial.Man-madefatiguecanberealizedbyapplyingarotatingbendingloadtoanotchedbar.Tobetterutilizethenewmethod,lasertreatmentisadoptedinthisstudy.Afterlaserradiationatthenotchroot,thefatiguecycleofthebardropsdramatically.Basedontheexperimentalresult,wedrawtheconclusionthatthefatigueofthebarisinfluencedbytheshapeofthehardenedarea.Ahardenedareathathasasmallaxialdimensionandarelativelylargeradialdimensionfacilitatesthefatigue.Thedesirablehardenedareacanbeobtainedbycontrollingthelasertreatmentparameters.
简介:
简介:Microbe-inducedcalciteprecipitationisasustainableimprovementtechniqueforsandysoil,whichcanalterthepropertiesofsandviamicrobialactivity.Inthisstudy,weinvestigatedtheloose-sand-consolidationeffectbycontrollingtheinjectionvelocity,bacterialandcementingsolutionconcentrations,andholdtimes.Theresultsdemonstratethat,asthecyclicbatchincreases,theutilizationrateofthebacterialfluidincreasesandboththeopticaldensity(OD600)ofthebacteriaandureaseactivitydecrease.Moreover,itwasdeterminedthata3-hholdtimefora0.5mol/Lcementingsolutionwithacementingfluidvelocityof2mL/minhasthegreatestbondingeffect.Thefinalstrengthoftheloosesandwithanincreaseincalciumcarbonatecontentwasfurtherdiscussed.
简介:Osteoarthritis(OA)isthemostcommonformofarthritis.ThekneeandhipjointsarethemostcommonsitesforOA,andkneeOAismoreprevalentthanhipOA.1KneeOApatientsoftensufferpain,functionaldisability,articularcartilagewearandrelatedjointspacenarrowing.AmongU.S.adults,46.4millionhavephysician-diagnosedarthritisrepresenting
简介:
简介:
简介:摘要:住宅项目地下停车库已成为拓展城市空间利用率的重要举措,地下车库作为车辆停、行主要场所,对地面使用功能、安全耐久的提出了更高的需求,金刚砂+固化剂一体化成型地面的技术逐渐普及。建设工程的前期的发展阶段,大量采用普通的混凝土地坪,项目实际的操作人员对金刚砂地坪工艺存在质量控制、技术要求的盲区,导致质量问题频发,主要体现在金刚砂完成面产生裂缝、工序安排不当造成成品破坏、多种颜色金刚砂混淆致使感观差、渗水处理不到位四方面的主要问题。实践表明,金刚砂施工采用凿毛、结浆工艺、不同颜色金刚砂施工时间流水搭接、定板取样、不同情况采取不同治理渗漏措施等一系列的技术措施,能够大幅度的提高金刚砂地面的成型质量和耐久性,满足感观和使用要求。