简介:Recentadvancesontheuseofnanocarbon-basedelectrodesfortheelectrocatalyticconversionofgaseousstreamsofCO2toliquidfuelsarediscussedinthisperspectivepaper.Anovelgas-phaseelectrocatalyticcell,differentfromthetypicalelectrochemicalsystemsworkinginliquidphase,wasdeveloped.Thereareseveraladvantagestoworkingasphase,e.g.noneedtorecovertheproductsfromaliquidphaseandnoproblemsofCO2solubility,etc.Operatingundertheseconditionsandusingelectrodesbasedonmetalnanoparticlessupportedovercarbonnanotube(CNT)typematerials,longC-chainproducts(inparticularisopropanolunderoptimizedconditions,butalsohydrocarbonsuptoC8-C9)wereobtainedfromthereductionofCO2.Pt-CNTaremorestableandgiveinsomecasesahigherproductivity,butFe-CNT,particularusingN-dopedcarbonnanotubes,giveexcellentpropertiesandarepreferabletonoble-metal-basedelectrocatalystsforthelowercost.ThecontrolofthelocalizationofmetalparticlesattheinneroroutersurfaceofCNTisanimportactfactorfortheproductdistribution.ThenatureofthenanocarbonsubstratealsoplaysarelevantroleinenhancingtheproductivityandtuningtheselectivitytowardslongC-chainproducts.TheelectrodesfortheelectrocatalyticconversionofCO2arepartofaphotoelectrocatalytic(PEC)solarcellconcept,aimedtodevelopknowledgeforthenewgenerationartificialleaf-typesolarcellswhichcanusesunlightandwatertoconvertCO2tofuelsandchemicals.TheCO2reductiontoliquidfuelsbysolarenergyisagoodattempttointroducerenewablesintotheexistingenergyandchemicalinfrastructures,havingahigherenergydensityandeasiertransport/storagethanothercompetingsolutions(i.e.H2).
简介:本文首先介绍了固定CO2的意义及方法,然后分析了微生物固定CO2技术流程,接下来阐述了微生物种群及生物反应器类型,最后重点讨论了微生物固定CO2的应用(以微型藻类在CO2吸收与资源化中的应用为例),以期为同行提供有益借鉴与参考。
简介:AnewkindofsimpleandflexibleCO_2weldingsystemwasdevelopedtocarryoutwaveformcontrol.ThesystemconsistedofIGBTinverter,PWMcircuitandmicroprocessorunit(MPU),inwhichtheoutputcurrentofconstantcurrent(CC)powersupplycouldbechangedaccordingtotransientphysicalstate,andthevariabledownsloperatecontrolcouldbeusedtoensureastableweldingprocess.Theweldingexperimentresultsprovedtheeffectivenessofthiscontrolapproach.
简介:Accuratelymeasuringthedifferentialmolecularabsorptioncrosssectionisthekeytoobtainingahigh-precisionconcentrationofatmospherictracegasesinadifferentialabsorptionlidar(DIAL)system.However,theCO2absorptionlineismeticulousat1.6μm,easilytranslatingandbroadeningbecauseofthechangeoftemperatureandpressure.Hence,measuringtheverticalprofileofatmospherictemperatureandpressuretocalculatetheverticalprofileoftheCO2weightparameterisnecessary.Ingeneral,measuringatmospherictemperatureandpressurehasacertainamountofuncertainty.Therefore,thisstudyproposestheconceptofabalancedon-linewavelength,wherethedifferentialmolecularabsorptioncrosssectionislargerandtheCO2weightparameterisinsensitivetotheuncertaintyofatmospherictemperatureandpressure.Inthisstudy,weanalyzedtheinfluenceofuncertaintyontheCO2weightparameterateverypreselectedwavelength,aswellasdeterminedanappropriatewavelengthnearoneoftheabsorptionpeaks.Ourresultshowsthat1572.023nmshouldbeoneoftheappropriatebalancedonlinewavelengths.ThemeasurementerrorsofthemixingratioofCO2moleculeinthiswavelengthareonly0.23%and0.25%andarecausedby1Ktemperatureerrorand1hPapressureerror,respectively.Thisachievementofabalancedon-linewavelengthwillnotonlydepresstherequirementofthelaser’sfrequencystabilizationbutalsothedemandformeasurementprecisionoftheatmospherictemperatureandpressureprofile.Furthermore,thisstudycanachievetheexactmeasurementoftheverticalprofileofatmosphericCO2basedonanindependentdifferentialabsorptionlaser.
简介:摘要:本文简单地叙述了二氧化碳气体保护焊(以下简称CO2焊)时气孔产生的原因、防止措施和气孔的种类及气孔的危害,对上焊接加工实训课有着重要的指导作用,能有效提高实训课教学质量。
简介:摘要:制冷剂替代的一个研究方向是使用天然工质,而CO2是常用的天然工质之一。本文首先介绍制冷剂的相关物理性质和热力学性质特点,说明CO2作为制冷剂的优越性。然后结合CO2跨临界循环系统介绍结构元器件选型和特点,重点讲述系统非标结构件管路件的选用参考。最后,介绍CO2制冷系统发展过程中面临的挑战和今后发展趋势。