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:介绍中美两国制冷空调行业协会在容积式CO2制冷压缩机(组)标准化合作方面的进展。对中国国家标准GB/T29030—2012《容积式CO2制冷压缩机(组)》和美国AHRI571:2012标准《容积式CO2制冷压缩机(组)性能评定》进行分析,主要从适用范围、试验工况、测试方法、试验参数及性能允差、计算参数、油循环率等方面对两国标准进行详细的对比。该分析研究有助于推进容积式CO2制冷压缩机(组)标准的国际化进程。
简介:选取凹凸棒作为乳化剂,系统研究pH、颗粒浓度、油相体积分数以及不同价态盐对橄榄油/水型Pickering乳状液稳定性的影响,结果表明,体系pH在4~9范围内可制备出稳定的乳状液;颗粒浓度的提高可增强乳液的分层和聚结稳定性;乳液液滴直径随油相体积分数的增加先增大后减小;无机盐的引入不会对乳液相及水相的体积产生影响,但对乳液液滴的尺寸分布影响显著,其中NaCl浓度的增加有利于乳状液液滴数均直径的增加,而CaCl2浓度增加时,乳状液液滴数均直径呈现先增大后减小的变化趋势。研究表明,凹凸棒可作为一种新型纳米乳化剂应用于绿色乳状液的制备。