简介:Recentresearchshowsthattheadditionofchitosanmicrospheres(CMs)topoly(L-lactide)(PLLA)canresultinacompositescaffoldmaterialwithimprovedbiocompatibilityandmechanicalpropertiesfortissueengineeringapplications.However,researchregardingtheinfluenceofCMsonscaffolddegradationisabsentintheliterature.ThispaperpresentsastudyontheinvitrodegradationofscaffoldsmadefromPLLAwithCMs.Inthisstudy,thePLLA/CMsscaffoldswitha25%ratioofCMstoPLLAwereimmersedinphosphate-bufferedsaline(PBS)solutionat37℃for8weeks.Theinvitrodegradationofthescaffoldswasinvestigatedusingmicro-computedtomography(μCT),weightlossanalysis,Ramanspectroscopy,anddifferentialscanningcalorimetry(DSC).MicrostructurechangesduringdegradationweremonitoredusingμCT.TheμCTresultswereconsistentwiththeresultsobtainedfromRamanspectraandDSCanalysis,whichreflectedthataddingCMsintoPLLAcandecreasethedegradationratecomparedwithpurePLLAscaffolds.TheresultssuggestthatPLLA/CMsscaffolddegradationcanberegulatedandcontrolledtomeetrequirementsimposedagiventissueengineeringapplication.
简介:磨擦促使处理(FSP)作为在12修理裂缝的一个方法被调查?公里厚304L不锈钢板。愈合的可行性被用一个PCBN/W-Re工具处理一个逐渐变细的裂缝与表明一25?公里直径肩膀和6.4的大头针长度?公里。实验证明愈合是可能的开始的一个裂缝狭窄然后日益增多地长大到2的宽度?公里。板实验上的祷告被用来为创造发现最好的参数一巩固与贱金属相比与坚硬差别的最少的数量搅动地区。在一些标本的谷物精炼更高导致了大部分搅动地区坚硬,与贱金属相比。谷物尺寸对microhardness的一个阴谋显示出在谷物尺寸和坚硬之间的很强壮的反的关联,从Hall-Petch关系期望。腐蚀测试被执行以便在stir地区的潜在的促进感受性上评估FSP的效果。在1000以后?在在没有腐蚀产品在基础材料控制上或在任何磨擦上形成了,这被发现的房间温度的3.5%盐溶液的断断续续的沉浸的h搅动处理标本。
简介:ThispaperpresentsanexperimentalinvestigationonanAISI316Lstainlesssteelregardingmechanicalproper-tiesandshortuniaxialcreeptestsatelevatedtemperatures.Theshorttimecreeptestswerecarriedoutunderdifferentbutconstantstresses.Theobtaineddataofultimatetensilestrength,yieldstrength,creepcurvesandeffectsofelevatedtemperaturesonmechanicalpropertieswerepresented.Foraselectedrheologicalmodel,materialparameterswereobtained.Asajustification,suchrheologicalmodelisimplementedinthefiniteelementprocedureforanuniaxiallystressedspecimeninselectedenvironmentalconditions.
简介:在各种各样的应力下面的316L不锈钢(316LSS)的Pitting腐蚀被potentiodynamic学习在3.5%NaCl答案的极化,电气化学的阻抗光谱学(EIS)和Mott-Schottky(MS)分析。极化曲线的结果证明随压力的增加,pitting潜力和被动当前的密度显著地减少firstly(180MPa),然后极大地增加(200MPa)。在极化测试以后的样品的相应表面形态学很好对应于结果。Mott-Schottky分析证明了在潜力与更积极的fl吸附到被动film的表面的最少的Cl,显示一个中等压力能增加在3.5%NaCl答案的316LSS的pitting腐蚀电阻。
简介:微距镜头是定焦镜头中的精品,是近距摄影的利器。在佳能EF系列庞大的镜头群中.生产在线的微距镜头仅有四款:EF50mm/1:2.5CompactMacroMP-E65mm/1:2.8Macro:EF100mm/1:2.8USMMacro:EF180mm/1:3.5LUSMMacro.唯独这款180mm的长焦微距是“L”级。从外形来看.这款EF180mm镜头实在有点貌不惊人,黝黑的镜体苗条得体,长而不肥,硕而不壮,比佳能EF70~200mm/2.8L的个儿“矮”了7mm,仅为186.6mm;“腰围”也细了2.1mm,仅为82.5mm;滤镜口径也小了5mm.仅为72mm。1090克的重量.适配于专业机身上,平衡性显得很好。
简介:Throughmeasuringthecoefficientoflinearexpansion,thestructureandpropertiesoftheLi2O-Al2O3-SiO2lowexpansionglassceramicscontainingB2O3arestudiedbyJRandXRD.ItisshoutnthattheIRmethodisefficientinthestudyoftheglass-ceramicsstructure.Thereisa"Boronabnormality"inthesystemwhichhasanimportantinfluenceonthepropertiesoftheglass-ceramics.
简介:TheelectronicstructuresofCuS2,CuSe2andCuTe2withpyritestructures,withintheframeworkthedensity-functionaltheoryhavebeeninvestigated.ThecalculatedresultsexplainedtherecentexperimentalresultswhichshowthatthereisnoclearindicationofstrongelectroncorrelationsintheelectronicpropertiesofCupyrites,duetothedominantchalcogenpcharacterratherthandcharacteristicofCuattheFermilevel.
简介:Overcasting是过去常生产铝(固体)的一种新有点不一样的加入技术结合的/magnesium(液体)在这研究的二金属的材料。为Al/Mg(A390/AM60)二金属的样品,接口微观结构是研究点,它直接影响机械性质。因此,发现一个方法改进接口微观结构具有重要重要性。这研究在二金属的样品的A390/AM60接口微观结构上在液体Mg合金和热处理在钙(Ca)的效果上集中了增加。严峻的结果证明与在AM60的Ca增加,由于二个可能的原因,接口微观结构和A390/AM60二金属的样品的shear力量能被改进。热处理能进一步由溶解-Mg17Al12进-Mg并且破坏Mg2Si层结构。
简介:Achievingnotonlyhighmechanicalstrengthsbutalsohighductilityisrecentlyestablishedusinganadditivemanufacturingtechniquecalledselectivelasermelting.Inthepresentstudy,stainlesssteel304Lfullydensesamplesweresuccessfullyprintedusingthe3Dsystems-ProX300printingmachine.TheductilityandtensileyieldstrengthwerealmosttwoandthreetimeshighercomparedtothoseofASTMcast'salloy.Honeycomblikenano-cellularstructurew让hdifferentorientationwasobservedinthefinegrains(-4μm)duetofastcoolingrate.Inadd让ion,theformationofmartensitephaseinrandomgrainsisalsoacontributortothestrengths.Furthermore,negativeresidualstressesinthebuildandhorizonraldirectionsweredetectedandassistedfurtherincreaseinthetensilestrength.Fractographyrevealedtheductilefeatureofplasticdeformationandthecrackopeningsatunmeltedparticlesorpores.