简介:Theprocessesreportedforthepreparationoflanthanumhexaboride(LaB6)fromlanthanumoxideinvolvetheuseofcarboneitherelementalorintheformofboroncarbideorelementalboronitselfasreducingagents,fusedsaltsathightemperaturesorreactionswhichrequiretheproductboridetobeleachedout.Eachofthesetechniqueseitherincreasestheprocesscostsand/orincreaseschancesofcontaminationinfi-nalproduct.PureLaB6canbestbepreparedbyareactionwhichproducesagaseousbyprodu...
简介:Amulti-bubbledynamicscodeaccountingforgasdiffusionintheliquidandthroughthebubblewallwasdevelopedandusedtostudythemodificationofabubblenucleipopulationdynamicsbyapropeller.ThepropellerflowfieldwasobtainedusingaReynolds-AveragedNavier-Stokes(RANS)solverandbubblenucleipopulationswerepropagatedinthisfield.Thenumericalpro-cedureenabledestablishmentofthepossibilityofproductionbehindthepropellerofrelativelylargevisiblebubblesstartingfromtypicaloceannucleisizedistributions.Theresultinglargerbubblesareseentoclusterinthebladewakesandtipvortices.Parametricinvestigationsoftheinitialnucleisizedistribution,thedissolvedgasconcentration,andthecavitationnumberwereconductedtoide-ntifytheireffectsonbubbleentrainmentandtheresultantvoidfractionsandbubbledistributionmodificationsdownstreamfromthepropeller.Imposedsyntheticturbulence-likefluctuationsuntotheaverageRANSflowfieldwerealsousedtostudytheeffectavera-gingintheRANSprocedurehasontheresults.
简介:一个维的Bose气体是不平常的超流体。与更高空间的尺寸相对照,非古典的旋转惯性的存在直接没被连接到无穷小的杂质的无驱散的运动。最近,有原子开始了的ultracold的试验性的测试和为drag力量的量的预言由动人的障碍经历了变得可得到。这热门评论讨论在与superfluidity的四轮马车标准的关系从线性反应理论获得的drag力量。基于在之上改进了动态结构因素的分析、数字的理解,不同障碍潜力的结果被获得包括单个杂质,光格子和随机的潜力从点缀模式产生了。在随机的潜力的superfluidity的动态故障在这些系统在与安德森本地化和预言的超流体绝缘体转变的关系被讨论。
简介:Sn(OH)4waspreparedbytheconventionalsolutionprecipitatemethod,followedbysupercriticalCO2drying.TheresultantSn(OH)4wasdividedintothreealiquotsandcalcinedat400,600and800°C,respectively,thusSnO2nanoparticleswithaveragecrystallitesizesof5,10and25nmwereobtained.Furthermore,threeSnO2thickfilmgassensors(denotedassensorsS-400,S-600andS-800)werefabricatedfromtheaboveSnO2nanoparticles.Theadhesionofsensingmaterialsonthesurfaceofaluminatubeisgood.ComparedtothesensorsS-600andS-800,sensorS-400showedamuchhighersensitivityto1000μL/Lethanol.Ontheotherhand,sensorS-800showedamuchlowerintrinsicresistanceandimprovedselectivitytoethanolthansensorsS-400andS-600.X-Raydiffraction(XRD),transmissionelectronmicroscopy(TEM)andselectiveareaelectrondiffraction(SAED)measurementswereusedtocharacterizetheSnO2nanoparticlescalcinedatdifferenttemperatures.Thedifferencesinthegassensingperformanceofthesesensorswereanalyzedonthebasisofscanningelectronmicroscopy(SEM).
简介:有最不消费精力和最大的效率的液化天然气(LNG)的适当生产是相当重要的。在这份报纸,借助于APCI过程的LNG生产周期被学习了。在APCI周期的每台设备的精力平衡方程和exergy平衡方程被建立。设备用严密热力学被描述,没有重要简化被假定。作为关键参数拿一些操作参数,性能(警察)和串联周期的exergy效率的系数上的这些参数的影响被分析。结果显示那个警察和exergy效率将与增加先生的入口压力被改进(混合致冷)压缩机,在precooling过程以后NG和先生减少,汽轮机的插头压力,先生压缩机的入口温度和在在主要的低温实验法的热exchanger(MCHE)冷却以后的NG温度。分别地,警察和APCI周期的exergy效率将在优化关键参数以后超过2%和40%。
简介:Thedifferencesofreductionbehaviorsbetweenironorelumpandpelletswerestudiedbyconductinglowtemperaturereductiondegradation,staticloadreductionanddroplettests.Thesetestssimulatedtheconditionsofreductiontemperatureandhydrogen-containinggasinCOREX.Duetoitsdensestructureandlowporositycomparedwithpellets,lumporepossessespoorreductiondegradationindex(RDI)andslowerreductionrateinearlyandmediumreactionstages,showingsignsoflowerstrength,lowersofteningandmeltingtemperatures,aswellasawidermeltingzoneandhigherΔP.Thatprovidessomebasistoexplainthephenomenaofdifferentialpressurerise,metallizationdeclineandmorestickingaftertheusageoflumporeinCOREXplant.
简介:Themaintechnologiesforreducingfluegasheatlossofpulverizedcoal-firedboilersareintroduced,andthesuitabilityofthesetechnologiesforboileroperationandtheprinciplesforselectionofthesetechnologiesareexplored.Themainconclusionsare:1)thenon-equilibriumcontroloverfluegasflowratesattheinletoftheairheaterandthereversalrotationoftheairheaterrotatorshouldbepopularizedasregulartechnologiesinlargeboilers;2)increasingtheareaoftheairheatertoreducethefluegasheatlossinpulverizedcoal-firedboilersshouldbethetopoptionandincreasingtheareaoftheeconomizerbethenextchoice;3)low-pressureeconomizertechnologycouldsaveenergyunderspecialconditionsandshouldbecomparedwiththetechnologyofincreasingeconomizerareaintermsoftechnicaleconomicswhenthelatterisfeasible;4)thehotprimaryairheaterisonlysuitabletothepulverizingsystemwithalargeamountofcoldairmixed.
简介:对待热的激活的碳(TAC)上的元素的水银俘获用实验室规模被学习固定的床反应堆。TAC的能力被学习在N2和基线气体气氛下面执行Hg0俘获,普通的酸气体成分的效果个别地被评估避免源于多重部件的共存的复杂并发症。结果建议激活的碳(交流)上的功能的组(SFG)是的那表面对当酸气体不在时的Hg0俘获重要。同时,酸气体部件的存在在TAC戏上结合了有缺点的graphitic格子在有效Hg0的一个重要角色俘获。HCl的存在,NO2,并且显著地个别地不由于Hg0的异构的氧化在TAC上在基本气体提高Hg0俘获在有缺点的graphitic格子在TAC上在碳表面和催化作用上创造的酸的地点上。同样,SO2的存在在大约20%改进Hg0俘获。这改进多半在碳表面上由于催化作用由SO2在AC表面和元素的水银的氧化上源于硫组的免职。而且,当酸气体在烟道气体是在场的时,O2在Hg0氧化和俘获上展出synergistic效果。