简介:Althoughtheperformanceofmembranereactors(MR)ishighlyaffectedbytheratioofmembranearea-toreactionvolume,therearefewstudiesonthiseffectowingtothedifficultiesassociatedwithreactormanufacture.Inthisstudy,anMRwithhighA/Vratio,adiameterof35m,andaheightof0.8mmwasfabricated.SeparationperformanceofthisMRwasinvestigatedinann-butanol/watersystem.Esterificationofaceticacidandn-butanolwasusedasthemodelreactiontoinvestigatetheperformanceofcatalyticallyactivemembranereactors(CAMR)withdifferentA/Vratios.Thereactionconversionwas38.59%intheCAMRwiththehighA/Vratioof12,497/m,whichwasmuchhigherthanthatinotherCAMRs,forreactiontimeof60minandW/Vfratioof0.093g/mL.ExcellentcatalyticstabilityoftheCAMRwasconfirmedbyperforminglong-termstabilityexperiments.
简介:2017年年初的一句“我可能复习了假书”走红后,互联网上立即涌现出一大批“假”现象,它们与传统的真假相背离,却受到社会的一致热捧。拟对“主语+可能+V了假N”进行句法和语义、语用上的考察,并分析“假”现象泛化的动态过程及其语用价值。
简介:INTRODUCTIONForChinesestudentsofEnglish,grammarlearningissoimportantthattheirtextbooksinevitablyentailgrammarsectionsorganizedinalinearway.ThesestudentstreatgrammarlearningasthesteppingstoneontheirwayofEnglishlearning.Theyhopetohaveagoodcommandofgrammarbothfortheirpresentlearningandfortheirfurtherstudies.Fortheirpresentlearning,theirlinguisticknowledgeistestedandassessedthroughexaminations
简介:本文系统及深入分析了单级与双级功率因数校正AC/DC变流器的性能特征,并指出各自存在的优缺点.在此基础上,结合软开关技术的特点,提出了一种基于集成化设计的功率因数校正AC/DC开关变流器电路,此类变流器克服了传统单级及双级变流器存在的不足,具有直接功率转换概念的新型功率因数校正电路的特点,它综合具有传统反激式升压转换器的功率传输特性,具有高效、高功率因数、成本低的特点;文中对新拓扑与传统拓扑在效率、功率因数以及直流输出电压等方面进行了比较,并通过一个150W/28V的电路模块进行了实验验证,并给出了实验结果,结果表明,新型PFC拓扑电路能显著地提高变流器的转换效率,比传统PFC电路转换器效率要高出5%.