简介:Theoccurrencemodesofalkaliandalkaline-earthmetals(AAEMs)incoalrelatetotheirreleasebehaviorandashformationduringcombustion.TobetterunderstandthetransformationofAAEMs,thereleasebehaviorofwater-soluble,HCl-soluble,HCl-insolubleAAEMsduringShenmucoal(SMcoal)oxy-fuelcombustioninthepresenceofSO2andH2Oinadrop-tubereactorwasinvestigatedthroughserialdissolutionusingH2OandHClsolutions.TheresultsshowthatthereleaseratesofAAEMsincreasewithanincreaseintemperatureunderthethreeatmospheresstudied.ThehighreleaseratesofMgandCafromSMcoalaredependentonthehighcontentofsolubleMgandCainSMcoal.SO2inhibitsthereleaseratesofAAEMs,whileH2Opromotesthem.TheeffectsofSO2andH2OontheNaandKspeciesaremoreevidentthanthoseonMgandCaspecies.AllthreetypesofAAEMsincoalcanvolatilizeinthegasphaseduringcoalcombustion.TheW-typeAAEMsreleaseexcessively,whereasthereleaseratesofI-typeAAEMsarerelativelylower.DifferenttypesofAAEMmayinterconvertthroughdifferentpathwaysundercertainconditions.BothSO2andH2Opromotethetransformationreactions.TheeffectofSO2wasrelatedtosulfateformationandthepromotionbyH2OoccursbecauseofadecreaseinthemeltingpointofthesolidaswellasthereactionofH2O.
简介:“So+主语+助动词’’与“So+助动词+主语”是初中英语中容易混淆的两个知识点,笔者根据教学实践对它们的区别作以下浅析,供同学们参考。
简介:AnewtypeofcomplexsolidsuperacidcatalystWO3-ZrO2-SO42-withanacidstrengthH0≤-16.04waspreparedbykneadingZr(OH)4oramorphousZrO2withtungsticacid(H2WO4)(W/Zr=0.15),followedbyexposingthiscomplexhydroxidesto0.5tool/LH2SO4,calcininginairat700~800℃for3h.ThiscatalystpossessesbothstrongBronstedacidityandstrongLewisacidityexperimentallyshowedbyIRobservationofpyridineabsorbedonit.XPSandAEStechniqueswereemployedtoexaminethevalencestatesoftungsten,zirconium,sulfurandtheirinteractions.Thestructureofsulfurspecieswasstudiedbyinfraredspectroscopyandastructuremodelofactivesitewasproposedupontheseresults.
简介:利用实施北京市奥运空气质量保障计划"北京市与周边地区空气污染物的输送、转化及北京市空气质量目标研究"项目的有利时机,于2007年1月15~27日在中国科学院大气物理研究所北京站、香河站和兴隆站,采用先进的差分吸收光谱仪(DOAS)和SO2气体分析仪取得了高质量SO2浓度的连续观测资料,同时还获取了相应的常规气象资料和系留气艇探测的常规气象参数廓线资料。分析和讨论了北京及其周边地区的SO2污染的变化过程特征、日变化特征、输送特征、源排放特征以及与天气过程和气象条件的紧密联系。研究表明:1)北京站、香河站和兴隆站的SO2浓度逐日变化明显,变化趋势一致,通常处于同一个天气系统控制之下,SO2污染呈现区域性分布特征。2)冬季SO2浓度日变化明显,夜晚最高,15时(北京时)最低。3)SO2浓度与大气稳定度、风速、风向密切相关,风速越小、大气越稳定,SO2浓度越高;当吹西南风时,SO2浓度升高,西北风时浓度明显降低。4)HYSPLIT后向轨迹数值模拟结果和OMI卫星反演表明周边地区的SO2长距离输送对站点的贡献不能忽视。
简介:【摘要】本文研究了以稀土纳米固体超强酸SO4 /ZrO2-CeO2为催化剂,以对硝基苯甲酸和乙醇酯化反应合成对硝基苯甲酸乙酯,考察了反应时间、催化剂用量、醇酸比以及催化剂重复使用等对产率的影响。当反应温度为80℃,催化剂用量为对硝基苯甲酸质量的5%,酸醇比(物质的量之比)为1:4,酯化反应时间120min时,产率可最高达到99.7%。该催化剂经活化再生后重复使用,保持很高的活性。
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简介:Kineticsofchloride/sulfate,chloride/nitrateandnitrate/sulfateforwardexchangesandreverseexchangesatsolutionconcentrationsof1N,0.2Nand0.02Non201×7strongbaseanionexchangeresin,respectively,havebeenexaminedat25℃.Itisfoundthattheforwardandthereverseexchangeratesofthetwogivenionsatlowsolutionconcentration,respectively,underidenticalconditionscanbecontrolledbydifferentmechanisms,whilethoseathighsolutionconcentrationareallcontrolledbyparticlediffusion.Theternaryexchangeratesofsulfate/(chloride+nitrate)andnitrate/(chloride+sulfate)havealsobeenexamined.
简介:ThecrystalgrowthprocessofZn(Leu)SO4·0.5H2OformwaterandacetonewasinvestigatedusingaCalvetmicrocalorimeter.Theheatandtherateofheatproductionduringthecrystalgrowthprocessat293.15K,295.15K,298.15Kand300.15Kweremensured.Onthebasisofexperimentalandcalculatedresults,therateconstantandthekineticparameters(theactivationenergies,thepre-exponential)duringthecrystalgrowthprocesswereobtained.Theresultsshowthatthecrystalgrowthprocesswereobtainged.TheresultsshowthatthecrystalgrowthprocessaccordedwiththeBurton-Cabrera-Franddislocationtheory.
简介:ThespinelLiMn2O4-x(SO4)xcompoundcathodematerialsweresynthesizedbysolid-statereactionofthecalculatedamountsofLiOH·H2O,MnO2andMnSO4.Theresultsoftheelectrochemicaltestdemonstratedthatthesematerialsexhbitedexcellentelectrochemicalproperties.Thehighestreversiblecapacityoftheseseriesofcathodematerialswas-120mAh/g,andafter50cycles,thisreversiblecapacitywasstillaround116mAh/gwithnearly100%reversibleefficiency,whichrevealedthatdopedsulfateioncouldimprovethestructuralstabilityofspinel.