简介:Anovelhighlyporous3-Dpoly(ε-caprolactone)(PCL)scaffoldwithmicro-channelswasfabricatedbyinjectionmoldinganddiluentaceticacidsleachingtechnologies.Inthisstudy,thechitosanfiberwasemployedtoformthemicrochannelinPCLmatrix.Themorphology,porosityandmechanicalpropertiesofthescaffoldswerestudiedandcalculated.Itwasfoundthatthelargerthecontentofchitosanfiberis,thehighertheporositywouldbe,duetothevolumetricexpansionofchitosanfiberinPCLmatrixduringitbeingleached.Inaddition,thelessthecontentofchitosanfiberis,thehigherthecompressivemoduluswouldbe.
简介:Amodifiedtorsionpendulumapparatusisdevelopedformeasuringtheshearmodulusofsinglefilamentswithuniformmicro-sizeddiameter.Asinglefilamentfixedatbothendsandwitharing-shapedmassattachedatthemiddleisusedasaclamped-clampedtorsionpendulum.Theshearmodulusofsinglefilamentscanbeexpressedasafunctionoftheoscillationfrequencyofthetorsionpendulum.TheoscillationmotionismeasuredwithaCCDlaserdisplacementsensor,anditsfrequencyisdeterminedbytheFastFourierTransform(FFT)method.Theshearmoduliofthreetypesoffilaments:copperwires,tungstenwiresandcarbonfibersareaccuratelymeasuredwiththistechnique.Itisfoundthatthesizeeffectinshearmoduliofbothcopperwiresandtungstenwiresisminor.Finally,theerroranalysisofourmeasurementtechniqueispresentedindetail.
简介:Fuelwoodisoneofthemajorsourcesofenergyinthedomesticsectoracrosstheruralareas,especiallyinthedevelopingregionsacrosstheworld.TheNortheasternHimalayanstateofManipurisdominatedbythetribalpopulationthatlargelydependsonfuelwoodfromthenearbyforestarea.Theentiredependenceonforestsforenergyresourcesisaffectingthesustainabilityoftheforestecosystemintheregion,thusindicatingthelivelihoodconditions.Sinceland-useland-coverchangeisthekeydrivertothechangeinresourceavailabilityofaregion,thepresentstudyhastriedtoanalyzethelandcoverchangesoveraperiod28years.Thesecondmajorcomponentaffectingresourceavailabilityistheincreasingpopulationpressurethatleadstochangesinthelanddynamics,whichdirectlyaffecttheresourceproduction.Basedontheexistingconsumptionpattern,thetotalconsumptionoffuelwoodinthewatershedrangesfiomaminimumof289.992tons/yeartoamaximumof3545.719tons/yearwithanaverageof1561.956tons/yearintheyear2009andsimulatedfuelwoodconsumptionfortheyear2021isaround1469.260tons/year.Ninedifferentprobablescenariosofresourceareproposedtocalculatethestressvaluethatcanbeusedbythepolicy-makersandplannersforsuitablepolicyimplementationatthemicrolevelwithacomplexsocialsystem.
简介:SmOHCO3micro/nanoparticleswerepreparedinwater/oil(W/O)reversemicroemulsioncomposedofcetyltrimethylammoniumbromide(CTAB),n-octane,n-butanol,Sm(NO3)3·6H2Oandureaaqueoussolutionbythecouplingrouteofhomogeneousprecipitationwithmicroemulsion.ThenanoparticleswerecharacterizedandanalyzedbyX-raypowderdiffraction(XRD),thermalgravimetricanddifferentialthermalgravimetricanalysis(TG-DTG),Fouriertransforminfraredabsorptionspectra(FT-IR)andscanningelectronmicroscope(SEM).TheresultsshowedthatthephaseSmOHCO3micro/nanoparticleswasinagreementwithpureorthorhombicphase.ThedifferentmorphologiesofSmOHCO3micro/nanoparticleswithgoodmonodispersityandsizewereobtainedbyregulatingthereactiontemperatureandreactiontime.PossibleformationmechanismsofthemorphologicalstructureofSmOHCO3wereproposedanddiscussed.
简介:摘要当今信息传递极速的社会,LED的出现给人们带来了希望之光。LED的特色之处一是节能,二是基本无电离辐射,三提高空间利用。LED点阵显示屏的发展前景极为广阔,目前正朝着更高亮度、更高耐气候性、更高的发光密度、更高的发光均匀性,可靠性、全色化方向发展。因为在此对基于单片机LED点阵广告屏进行设计。