简介：Reaction-diffusion(RD)equationwasoftenusedtoinvestigatethepatterndynamics,buttelegraphreaction-diffusion(TRD)systemwasseldomstudied.Inthispaper,theIzhikevichmodelwasmodifiedtoexplainsomebiologicalmechanismsbyRDandTRDinneuronalcluster.Thenanewconditionunderwhichthesystemlosesstabilitywasproposedandtheeffectofparameters,diffusion,memoryandsteadystatewereconsideredontheprocessofneuronalspiking.Themethodpresentedisanovelapproachtoinvestigatethepatterndynamicsofbiologicalsystems.Finally,simulationsarecarriedouttovalidateourtheoreticalresults.

简介：TheArrheniuslawimpliesthatreactionrateisacontinuousfunctionoftemperature.However,thesteadylaminarflameletmodel(SLFM)doesnotexplicitlygivethisfunctionalrelationship.ThepresentstudyaddressesthisrelationintheSLFM.Itisfoundthatreactionrateisnotcontinuousinthemixture-fractionspace.Asaresult,theSLFMisunabletopredictlocalextinctionandreignition.Furthermore,weusetheunstablebranchofthe"S-curve"tofillthegapbetweensteadyburningbranchandextinctio...

简介：NanocrystallineSnO2wassynthesizedbydirectmixingandgrindingofSnCI4-5H2OandNaOHatroomtemperature,followedbycalcinationatdifferenttemperaturesfordifferenttimesinair.ProductsampleswerecharacterizedbyX-raydiffractionandtransmissionelectronmicroscope,revealingthattheamorphousprecursorSnO2wastransformedtocrystalsat200℃for3h,andthattheaverageparticlesizeincreaseduponraisingthecalciningtemperatureorprolongingthecalciningtime.Themechanismofthephasetransformationoftheproductsisdiscussed.

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：Acleanmethodforpreparinglayereddoublehydroxides(LDHs)hasbeendeveloped,featuredbyusingthehydroxidesoftwodifferentmetalsasstartingmaterialsbyatom-economicreactions.Thereactionswerecarriedoutunderhydrothermalconditionsineitherahighpressureautoclaveoramicrowavedigester.Thecompositions,structuralparametersandthermalbehavioroftheresultingLDHsareverysimilartothoseofmaterialsproducedbyusingtheseparatenucleationandagingsteps(SNAS)method.Themajoradvantageofthenewmethodisthatnoby-productisproduced,sothatfiltrationandwashingprocessesareunnecessary.Theconsequentreductioninwaterconsumptionisbeneficialtotheenvironment.

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简介：AnovelHeckreactioncatalystconsistingofapalladium（Ⅱ）complexofmeso-tetra（phydroxyphenyl）porphyrin（MTP）andcross-linkedchloromethylatedpolystyrenemicrospheres（PMs）wassuccessfullypreparedviacovalentetherbondsbetweenthechloridegroupsinthePMsandthehydroxylgroupsinMTP.Thecatalystwascharacterizedusingscanningelectronmicroscopy,Fourier-transforminfraredspectroscopy,andinductivelycoupledplasmaatomicemissionspectroscopy（ICP-AES）.Thispolystyrene-supportedpalladium-complexwasanefficientheterogeneouscatalystforcross-couplingofaryliodideswithethylacrylate.ThereactionofiodobenzeneandethylacrylateunderN2at100℃andacatalystconcentrationof0.1%gaveagaschromatographyproductyieldof99.8%,whichismuchhigherthanthatachievedusingafreepalladium（Ⅱ）complexofMTPasthecatalyst（41.3%）.Thecatalystwasrecycleduptosixtimeswithoutsignificantlossofcatalyticactivity.Theseresultssuggestthattheimmobilizedpalladium（Ⅱ）-MTPcatalysthaspotentialapplicationsinsyntheticandindustrialchemistry.

简介：Thispaperstudiesmixedconvection,doubledispersionandchemicalreactioneffectsonheatandmasstransferinanon-Darcynon-Newtonianfluidoveraverticalsurfaceinaporousmediumundertheconstanttemperatureandconcentration.Thegoverningboundarylayerequations,namely,momentum,energyandconcentration,areconvertedtoordinarydifferentialequationsbyintroducingsimilarityvariablesandthenaresolvednumericallybymeansoffourth-orderRunge-Kuttamethodcoupledwithdouble-shootingtechn...

简介：AnanostructuredNiAPSO-34catalystwashydrothermallysynthesizedandtheeffectofthetemplate（diethylamine（DEA）,tetraethylammoniumhydroxide（TEAOH）andDEA/TEAOH）onthephysicochemicalpropertiesandcatalyticperformanceinthemethanoltoolefin（MTO）reactionwasinvestigated.ThesampleswerecharacterizedbyX-raydiffraction,fieldemissionscanningelectronmicroscopy（FESEM）,particlesizedistributionanalysis,energy-dispersiveX-rayspectroscopy,Brunauer-Emmett-TelleranalysisandFouriertransforminfraredspectroscopy.TheX-raydiffractionpatternsindicatedahighercrystallinityandlargercrystallitesizeforthecatalystsynthesizedusingtheDEAtemplate.TheFESEMresultsindicatedthatthenatureofthetemplatecouldaffectthemorphologyofthenanostructuredNiAPSO-34catalystbecauseofitseffectontherateofcrystalgrowth.ThecatalyticperformanceofthesampleswasstudiedintheMTOreactionatatmosphericpressureandaspacevelocityof4200cm3/(gh-1)inafixedbedreactor.ThestabilityandactivityoftheNiAPSO-34catalystwereimprovedusingtheDEAtemplatebecauseofitshighercrystallinity,surfaceareaandthegreaterextentofNiincorporationintoitsframework.ThepossiblestagesofsynthesisandthereactionmechanismfortheMTOprocessoverNiAPSO-34arediscussedindetail.