简介:Variousagriculturalcropresiduesincludingcornstover,corncob,andsorghumstalkwithamoisturecontentof75wt%weresubjectedtoalongpretreatment(12-60h)withsupercriticalCO2(scCO2),atlowtemperature(50-80℃)andapressureof17.5-25.0Mpa.Thesugaryieldsfromtheenzymatichydrolysis(EH)ofthepretreatedsampleswereasmuchasthree-tofourfoldgreaterthanthoseaffordedbytherawmaterials.However,whenpretreatmentwasconductedwithinashorttime(e.g.0.5h),aspreviouslyreportedintheliterature,onlyaslightincreaseintheEHsugaryieldswasobserved.TheproposedscCO2pretreatmentmechanismdemonstratedtheroleofmoistureinthesystem.Wetting,softening,andswellingwereobservedtomainlyaffectthelignocellulosewhenasuitableamountofwaterwasadded.Finally,thesampleswereanalysedbyX-raydiffractionandscanningelectronmicroscopy,beforeandafterpretreatment,toinvestigatethechangesinthemicroscopicstructureofthebiomass.
简介:Anovelgas-phaseelectrocatalyticcellcontainingalow-temperatureprotonexchangemembrane(PEM)wasdevelopedtoelectrochemicallyconvertCO2intoorganiccompounds.TwodifferentCu-basedcathodecatalysts(CuandCu-C)werepreparedbyphysicalvapordepositionmethod(sputtering)andsubsequentlyemployedforthegas-phaseelectroreductionofCO2atdifferenttemperatures(70-90℃).ThepreparedelectrodesCuandCu-CwerecharacterizedbyX-raydiffraction(XRD),X-rayphotoemissionspectroscopy(XPS)andscanningelectronmicroscopy(SEM).Asrevealed,CuispartiallyoxidizedonthesurfaceofthesamplesandtheCuandCu-Ccathodiccatalystswerecomprisedofaporous,continuous,andhomogeneousfilmwithnanocrystallineCuwithagrainsizeof16and8nm,respectively.Theinfluenceoftheappliedcurrentandtemperatureontheelectro-catalyticactivityandselectivityofthesematerialswasinvestigated.Amongthetwoinvestigatedelectrodes,thepureCucatalystfilmshowedthehighestCO2specificelectrocatalyticreductionratesandhigherselectivitytomethanolformationcomparedtotheCu-Celectrode,whichwasattributedtothehigherparticlesizeoftheformerandlowerCuO/Curatio.Theobtainedresultsshowpotentialinterestforthepossibleuseofelectrical「enewableenergyforthetransformationofCO2intovaluableproductsusinglowmetalloadingCubasedelectrodes(0.5mgCucm2)preparedbysputtering.
简介:内容摘要改革开放以来,我国的经济迅速发展,在大型铸件铸造方面,铸造技术和铸造方法随着经济的发展也处于不断的创新中,在这个过程中,铸件会出现气孔、缩松、裂纹等各种缺陷,影响铸件的机械性能和使用安全,通常可以将缺陷清除后,选择相同、相似或者更优的焊材进行铸件补焊。针对以上问题,本文对手工电弧焊与二氧化碳气体保护焊进行了详述的概括,分析讨论了二者的优缺点,并且通过实验,在保证了试块拉伸、弯曲、冲击、硬度等机械性能的情况下,针对不同的焊块类型,确定出合理的焊接工艺及相应的焊后热处理方法,并且研究了手工电弧焊与二氧化碳气体保护焊相结合的创新方法,一定程度上增强了焊铸的效率,为铸件缺陷补焊工作提供了有力的技术支持。
简介:摘要目的了解祥云县医疗卫生机构医务人员主动提供的艾滋病检测咨询(PITC)实施情况,倡导PITC的进一步推广,为祥云县防治艾滋病工作提供科学依据。方法按照PITC工作规范、流程及相关工作内容要求,收集相关信息,分析2010年7月-2016年12月艾滋病病毒抗体筛查情况、按样本来源进行统计。结果祥云县医疗卫生机构医务人员共主动提供艾滋病检测咨询260124人次,占总检测数的51.79%(260124/502222),检出HIV抗体阳性250例(新报告170例),占全县新报告艾滋病感染者/病人的42.8%。结论祥云县通过医疗卫生机构的医务人员主动提供咨询HIV检测极大的提高了艾滋病病毒感染者和病人检测率。对于艾滋病感染者降低病死率,及时得到高危行为改变和随访管理,减少艾滋病的二代传播,有效降低新发感染率的意义十分显著。在HIV高流行区应该更加深入广泛开展PITC工作。