简介:Background:RunningisbecominganincreasinglypopularactivityamongAmericanswithover50millionparticipants.Runningshoeresearchandtechnologyhascontinuedtoadvancewithnodecreaseinoverallrunninginjuryrates.Agrowinggroupofrunnersaremakingthechoicetotrytheminimalorbarefootrunningstylesofthepre-modemrunningshoeera.Thereissomeevidenceofdecreasedforcesandtorquesonthelowerextremitieswithbarefootrunning,butnocleardataregardinghowthiscorrespondswithinjuries.Thepurposeofthissurveystudywastoexaminefactorsrelatedtoperformanceandinjuryinrunnerswhohavetriedbarefootrunning.Methods:TheUniversityofVirginiaCenlcrforEnduranceSpor!createda10-questionsurveyregardingbarefootrunningthaiwa.spo.stedonavarietyofrunningblogsandFacebookpages.Percentageswerecalculatedforeachquestionacrossallsurveys.Fivehundredandnineparticipantsrespondedwithover93%ofthemincorporatingsometypeofbarefootrunningintotheirweeklymileage.Results:Amajorityoftheparticipants(53%)viewedbarefootrunningasatrainingtooltoimprovespecificaspectsoftheirrunning.However,closetohalf(46%)viewedbarefoottrainingasaviablealternativetoshoesforloggingtheirmiles.Alargeportionofrunnersinitiallytriedbarefootrunningduetothepromiseofimprovedefficiency(60%).anattempttogetpastinjury(53%)and/ortherecentmediahypearoundthepractice(52%).Alargemajority(68%)ofrunnersparticipatinginthestudyexperiencednonewinjuriesafterstartingbarefootrunning.Infact,mostrespondents(69%)actuallyhadtheirpreviousinjuriesgoawayafterstartingbarefootrunning.Runnersrespondedthattheirpreviousknee(46%),foot(19%),ankle(17%),hip(14%),andlowback(14%)injuriesallproceededtoimproveafterstartingbarefootrunning.Conclusion:Priorstudieshavefoundthatbarefootrunningoftenchangesbiomechanicscomparedtoshodrunningwithahypothesizedrelationshipofdecreasedinjuries.Thispaperreports
简介:Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.
简介:阶段地水晶(陆军)模型被用来模仿premelting脱臼运动对称当系统温度在时,在紧张行动下面倾斜谷物边界(STGB)远非,到融化的融化的点和结束分别地指。结果证明当premelting温度被接近到,本地premelting发生包围脱臼从在温度下面。STGB的premelting脱臼能在紧张行动下面滑行,并且premelting区域是为脱臼滑行的一个同伴。STGB腐烂的过程以二个高温度条件是很类似的。当premelting介绍,它减少为脱臼的滑行抵抗并且导致脱臼的一个更快的运动,并且也在STGB的腐烂过程期间引起系统的更多的精力减小。尽管有把紧张用于这些,premelting在STGB的整个腐烂过程取样,premelting脱臼区域显然不发展并且延长。这显示外部紧张行动不在高温度支持premelting,并且不能导致更多的premelting脱臼,它能在脱臼展览附近被欠到premelting阶段像液体的性质并且到容易滑行并且放松紧张精力的premelting脱臼;这与实验和分子的动力学的结果一致。
简介:Melt-spunribbonswhicharetheimportantrawmaterialforhot-deformedmagnetscanbepreparedbysingle-rollermelt-spinning.Inordertopreparewell-structuredribbons,themodeloftemperaturefieldforsingle-rollermelt-spinningprocesswasconstructedinthiswork.Theheatconductioninthisprocesswassimplifiedasonedimensionalheatconductionproblem.Itwasshownbymodelingthat,thetemperaturefieldinthemelt-spinningbeforesolidificationinthismodelcouldbedescribedasthisequationT(x,t)=Tmoexp[–k(x–x0)–k2αt]+T0.ThetemperatureT(x,t)ofthealloymeltsdecreasedwithincreasedpositionxandcoolingtimetexponentiallyfromthewheel-freesurfacetothewheel-sidesurface.TheconstantkdeterminedthedecreasespeedofalloytemperatureT(x,t),whichwasproportionaltotheinterfacialheattransfercoefficienthandtheinterfacialareaofheatconductionA0,butinverselyproportionaltothethermalconductivityK.x0wasthethicknessofthealloymelt.Withincreasedx0,thetemperaturedifferencebetweenwheel-freesurfaceandthewheel-sidesurfacebecamelarger,whichwouldleadtolargerdifferenceingrainsize.Inexperiments,theinfluenceofmelt-spinningprocessparametersonthetemperaturefieldmodelwasdiscussed,suchascoolingrollermaterials,wheelspeed,andsoon.Melt-spunribbonspreparedbysingle-rollermeltspinningatdifferentwheelspeedwereinvestigatedandmagneticpropertiesofdie-upsetmagnetsfrommelt-spunribbonsondifferentcoolingrollerwereanalyzed.Thevariationofgrainsizeinthedepthdirectionconsistedwithtemperaturefieldmodel.Thismodelprovideddirectionsforthepreparationofmelt-spunribbonswithuniformlydistributedfinegrains,whichwereverynecessaryforproducinghot-deformedmagnetswithhighmagneticperformance.
简介:Thereciprocitymeasurementtheoryinanomalousreverberantsoundfieldswasinvestigated.AnimprovedmethodWasproposedduetotheinterrelatederrors.ThesourcevolumevelocityWascorrectedbyspatialaverageofmeasurementresultsandevaluationofthereverberantsoundfieldinfluenceonacousticenergydensity.Theresultwasvalidatedinunderwaterexperiment,correctedreciprocitymeasurementresultswerealmostthesameasdirectmeasurementresults.Itindicatesthatreverberantsoundfielddoesnotaffectthevaliditvoftheprinciple,butinfluencestheobtainmentofsourcevolumevelocity,theninfluencesthemeasurementoftransferfunctionswiththeprinciple.Theproposedmethodissimpleandeffectiveinanomalousreverberantsoundfields.Thestudymavbevaluablefortheapplicationswhicharebasedontheprinciple.
简介:Toremovethescatteringeffectofthedisturbingsoundonthetargetsourcewhenimplementingnearfieldacousticholographyinanon-freefield,afreefieldrecoverytechniquebasedonthesphericalwavesuperpositionmethodisproposed.Inthemethod,thesoundfieldseparationtechniquebasedonthesphericalwavesuperpositionmethodisfirstusedtoseparatetheincomingandoutgoingfields,andafurtherstepforseparatingtheradiatedandscatteredfieldsisperformedbyutilizingthesurfaceadmittanceofthetargetsourceastheboundaryconc1ition.Thetechniquemakesitpossibletocorrectlyidentifynoisesourcesinanon-freesoundfeld.Thebasicprincipleofthetechniqueisdescribedfirstly,amethodforchoosingtheoptimalnumberofsphericalwaveexpansiontermsisgiven,andtwonumericalsimulationsareusedtodemonstratethevalidityofthistechnique.Itisshownthat,forthelowerfrequency,thescatteringeffectcanbeneglected,andtheradiatedfieldofthetargetsourcecanbeobtainedbythesoundfieldseparationtechnique,however,astheincreasingofthefrequcncy,thescatteringeffcctcannotbeneglected,andthefrecfieldrecoverytechniquehastobeusedtoobtaintheradiatedfieldofthetargetsource.
简介:阶段地水晶(陆军)模型被雇用与格子失配和一个小倾斜角度在飞机凸的底层上模仿取向附生的层的生长的过程。系统的免费精力,取向附生的层的全部的原子序数,和弯曲和底层的角度的效果的变化被分析。结果证明当底层的表面是飞机时,免费精力随底层倾斜角度的增加增加,并且也,取向附生的层的全部的原子序数增加;当底层的表面是凸的时,免费精力随底层角度并且那么也的增加减少取向附生的层减少的全部的原子序数。这是取向附生的层的表面的边疆与增加凸的底层的倾斜角度从步bunching改变到hill-and-valley方面结构的原因。这些结果在对另外的方法结果的好同意。
简介:ToretrievewindfieldfromSARimages,thedevelopmentforsurfacewindfieldretrievalfromSARimagesbasedontheimprovementofnewinversionmodelispresent.GeophysicalModelFunctions(GMFs)havebeenwidelyappliedforwindfieldretrievalfromSARimages.AmongthemCMOD4hasagoodperformanceunderlowandmoderatewindconditions.AlthoughCMOD5isdevelopedrecentlywithamorefundamentalbasis,ithasambiguityofwindspeedandashapegradientofnormalizedradarcrosssectionunderlowwindspeedcondition.ThisstudyproposesamethodofwindfieldretrievalfromSARimagebycombiningCMOD5andCMOD4FiveVV-polarisationRADARSAT2SARimagesareimplementedforvalidationandtheretrievalresultsbyacombinationmethod(CMOD5andCMOD4)togetherwithCMOD4GMFarecomparedwithQuikSCATwinddata.Theroot-mean-squareerror(RMSE)ofwindspeedis0.75ms-1withcorrelationcoefficient0.84usingthecombinationmethodandtheRMSEofwindspeedis1.01ms-1withcorrelationcoefficient0.72usingCMOD4GMFaloneforthosecases.TheproposedmethodcanbeappliedtoSARimageforavoidingtheinternaldefectinCMOD5underlowwindspeedcondition.
简介:Energystorageplaysanincreasinglyimportantroleinmodernpowersystems.Itcanaddvaluetopowersystemsinvariousaspects.Thispaperdiscussespossibleenergystoragesystem(ESS)applicationsandtheirbenefitstopowersystems.Thesystemconfiguration,converterdesign,andrecentfieldinstallationsofanLVconverterbasedESSarepresented.
简介:Regardforthefuzzinessandtherandomnessinsomeacousticfields,amethodforthenumericalanalysisofthe2DacousticfieldwithFuzzy-Randomparameterswasproposedbasedontheequivalentconversionofinformationentropy.Intheproposedmethod,afuzzyrandomacousticfieldwastreatedasapurefuzzyacousticfieldorapurerandomacousticfieldbytransformingallthevariablesintofuzzyvariablesorrandomvariables.Perturbationfiniteelementmethodsforanalyzingthetwo-dimensionalacousticfuzzyandrandomfieldarededuced.Thesoundpressureresponseofa2Dacoustictubeandthe2Dacousticcavityofacarwithfuzzy-randomparameterswereanalyzedbytheproposedmethodandtheMonteCarlomethod,theresultsshowthattheproposedmethodcanbewellappliedtothenumericalanalysisofthe2Dacousticfieldwithfuzzy-randomparameters,andhasgoodprospectofengineeringapplication.
简介:Inthisstudy,themainfactorsinfluencingthemeasurementsbymeansoftheoff-linelow-field1HNMRinthelabwerediscussedbaseonarobustcalibrationmodelestablishedbythePLSalgorithmusing255crudeoilsamples.Thepreheatingtemperaturehadagreatinfluenceontheviscosityofoilsamplesandtheresolutionofspectralanalysis.Therepeatabilityofspectralmeasurementswasimpactedbythemetalandwaxcontentoftheoilsamples.Forthecaseofhighwaxcontentoils,thewaxspeciesbegantocrystallizeinthecourseofdeterminationthatcouldaffecttherepeatabilityofspectralmeasurements.ThesefactorshaveevidencedwhythepreheatingdevicesandfilterunitarenecessarywhenlowfieldNMRsystemisusedintheonlineanalysisprocess.Theinvestigationisveryimportantfortheon-lineapplicationofthelowfieldNMR.
简介:Foracompression-shearmixedmodeinterfacecrack,itisdifficulttosolvethestressandstrainfieldsconsideringthematerialviscosity,thecrack-tipsingularity,thefrictionaleffect,andthemixedloadinglevel.Inthispaper,amechanicalmodelofthedynamicpropagationinterfacecrackforthecompression-shearmixedmodeisproposedusinganelastic-viscoplasticconstitutivemodel.Thegoverningequationsofpropagationcrackinterfaceatthecrack-tiparegiven.Thenumericalanalysisisperformedfortheinterfacecrackofthecompression-shearmixedmodebyintroducingadisplacementfunctionandsomeboundaryconditions.Thedistributedregularitiesofstressfieldoftheinterfacecrack-tiparediscussedwithseveralspecialparameters.Thefinalresultsshowthattheviscosityeffectandthefrictionalcontacteffectonthecracksurfaceandthemixed-loadparameterareimportantfactorsinstudyingthemixedmodeinterfacecracktipfields.Thesefieldsarecontrolledbytheviscositycoefficient,theMachnumber,andthesingularityexponent.
简介:Thecreationandpropagationoflongitudinalacousticphonons(LAPs)inhighqualityhematitethinfilms(α-Fe2O3)epitaxiallygrownondifferentsubstrates(BaTiO3,SrTiO3,andLaAlO3)areinvestigatedusingthefemtosecondpump–probetechnique.Transientreflectionmeasurements(?R/R)indicatethephoto-excitedelectrondynamics,andtheinitialdecaylessthan1psandtheslowdecayof~500psareattributedtotheelectron-LOphononcouplingandelectron–holenonradiativerecombination,respectively.LAPsinα-Fe2O3filmcanbecreatedbyultrafastexcitationoftheligandfieldstate,suchastheligandfieldtransitionsunder800-nmexcitationaswellastheligandtometalcharge-transferwith400-nmexcitation.Thestrainmodulationsofthesoundvelocityandtheout-of-planeelasticpropertiesaredemonstratedinα-Fe2O3filmondifferentsubstrates.
简介:这研究检验从一种蚊虫quinquefasciatus的一张领域人口在单个蚊子涉及permethrin抵抗的开发的基因变化和机制,HAmCqG0,并且与领域HAmCqG0紧张。六upregulated细胞色素P450基因,CYP9M10,CYP9J34,CYP6P14,CYP9J40,CYP6AA7,和CYP4C52v1,以前作为是在抵抗HAmCqG8蚊子在3紧张的幼虫被检验(易受影响的平板,父母HAmCqG0和选择permethrin的高度抵抗的HAmCqG8)和8HAmCqG0单个鸡蛋的木排殖民地,盖住危险性/抵抗的层次的一个范围到permethrin并且在t展出不同变化有到permethrin的最低忍耐的2根线并且从殖民地Cx_SERC5和Cx_SERC8,完全在钠隧道的L-to-Fkdr地点忍受易受影响的A等位基因显示出与平板紧张相比测试的所有6P450基因的更低或类似的层次,建议这2排队能在在HAmCq蚊子描绘杀虫药剂抵抗的未来研究被用作参考蚊子。这研究也提供在一张人口以内在个人涉及杀虫药剂抵抗的机制的详细调查:有到permethrin的抵抗的提高的层次的个人都显示了提高的抵抗机制任何一个在钠隧道,或两个P450基因表示,或L-to-F变化铺平的至少一个潜力。