简介：本文利用群论的知识,从CH4的分子结构出发,研究了群C4v的特征及其特征表的性质,所得结论与用化学方法是相同的.

简介：CH4emissionrateshavebeenmeasuredcontinuouslyfortheearlyriceof1988andlatericesof1987and1988duringentiregrowingseasonsinaricepaddyfieldinHangzhou,ZhejiangProvince,China,byusinganautomaticsamplingandanalyzingsystem.DuringmostpartsoftheseasonsCH4emissionratesshowedstrongdiurnalvariations.Bi-modepatternswiththehighestvalueintheafternoonandasecondpeakatmid-nightweregenerallyfoundfortheearlyrice,whilethehighestvalueswerealmostalwaysfoundinthenightforthelaterice.Bi-modepatternswithasecondpeakintheafternoonwerealsofoundduringthereproductivephaseofthelatericeplants.Thesediurnalvariationsmaybeexplainedbythediurnalvariationsofthesoiltemperatureandtheactivityofriceplants.Strongseasonalvariationswithonepeakinthetilleringstageandtwoduringthereproductivephaseofriceplantswereobservedforallthethreegrowingseasons.Theseasonalvariationsmaybeexplainedbytheactivityofriceplants,availabilityoforganicsubstratesinthesoil,andtheactivityofsoilbacteriarelatedtosoiltemperatures,FertilizationdidnotshowsignificanteffectsonthetotalseasonalCH4emissionsbutslightlychangedthepatternoftheseasonalvariationsoftheCH4emissionrates.Averagedoverthemeasuringperiodsand8spots,CH4emissionratesof7.8mgm-2h-1fortheearlyriceand28.6mgm-2h-1forthelatericewereobtained.Basedonthesemeasureddata,thetotalglobalemissionofCH4fromricepaddiesisestimatedtobeabout90Tg/yrrangingfrom70to110,accountingfor20%ofthetotalsourceofCH4.

简介：InthispaperweusedMOF-5andCu3(BTC)2toseparateCO2/CH4andCH4/N2mixturesunderdynamicconditions.Bothmaterialsweresynthesizedandpelletized,thusallowingforameaningfulcharacterizationinviewofprocessscale-up.ThematerialswerecharacterizedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM).Byperformingbreakthroughexperiments,wefoundthatCu3(BTC)2separatedCO2/CH4slightlybetterthanMOF-5.BecausethecrystalstructureofCu3(BTC)2includesunsaturatedaccessiblemetalsitesformedviadehydration,itpredominantlyinteractedwithCO2moleculesandmoreeasilycapturedthem.Conversely,MOF-5withasuitableporesizeseparatedCH4/N2moreefficientlyinourbreakthroughtest.

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简介：Alowpoweratmosphericpressureplasmajetdrivenbya24kHzACpowersourceandoperatedwithaCH4/airgasmixturehasbeeninvestigatedbyopticalemissionspectrometer.Theplasmaparametersincludingtheelectronexcitationtemperature,vibrationaltemperatureandrotationaltemperatureoftheplasmajetatdifferentdischargepowersarediagnosedbasedontheassumptionthatthekineticenergyofthespeciesobeystheBoltzmanndistribution.TheelectrondensityatdifferentpowerisalsoinvestigatedbyHβStarkbroadening.Theresultsshowthattheplasmasourceworksundernon-equilibriumconditions.Itisalsofoundthatthevibrationaltemperatureandrotationaltemperatureincreasewithdischargepower,whereastheelectronexcitationtemperatureseemstohaveadownwardtrend.Theelectrondensityincreasesfrom0.8×1021m-3to1.1×1021m-3whenthedischargepowerincreasesfrom53Wto94W.

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简介：ThispaperpresentsabriefoverviewofCO2reformingofCH4（CRM）byvariousformsof'arc'plasma,whichismoresuitabletoCRM,andtheenergyefficiencyisusedtoevaluatedifferentplasmaprocessesspecifically.Accordingtothereportedresults,thearcthermalplasmawithbinodeexhibitedbetterperformance.Moreover,theplasmaCRMprocesswascomparedwiththereportedplasmasteamreformingofCH4（SRM）process,andtheresultsshowedthattheformerprocesshasadvantagesonenergyefficiencyandCH4consumption.Additionally,itisbelievedthattheplasmaCRMprocesswouldbecompetitivewiththeconventionalSRMprocessinbothenergyefficiencyandCO2emissiononcetheheatmanagementisemphasizedandtherenewablepowerisused.Finally,aconceptofplasmareactorforindustrialapplicationisproposed.

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简介：Netemissioncoefficientsofradiationwerecalculatedforisothermalplasmaofmethaneasafunctionoftheplasmatemperature5,000～30,000Kandthearcradius0mmto10mmatatmosphericpressure.Calculationstakeintoaccountcontinuumandlineradiations,specialattentionhasalsobeengiventotheinfluenceofoverlappingspectrallines.ThelineshapesinourcalculationsaregivenbyconvolutionofDopplerandLorentzprofiles,resultinginasimplifiedVoigtprofile.Inthecaseofahydrogenprofile,weusedtheVidaltables,andthefourfirstLymanlinesandthefourfirstBalmerlineswereconsidered.Thiscalculationwascarriedoutontheassumptionoflocalthermodynamicequilibriumandinanondiffusiveenvironment.ThenetemissioncoefficientcalculationforpureargonplasmawascomparedwiththeexperimentalresultsofEvansinourpreviouswork.Weusedtheescapefactor,andourresultswerehigherthanthoseoftheexperiment.Inthispaper,weexplainwhy,usingtheescapefactor,theradiationisoverestimated.ThenetemissioncoefficientobtainedfromarealspectrumwascomparedwithEssoltaniwork’swhichusedtheline-by-linemethodforpureargonplasma.

简介：Attheambienttemperatureandpressureaglowdischargeplasmawasusedasanewapproachforthecouplingofmethanewiththenewly-developedrotarymultidentatehelixelectrode.Inthepresenceofhydrogen,theeffectsoftheinputpeakvoltagesandgasflowratesonmethaneconversion,C_2singlepassyieldandselectivitywereinvestigated,andthentheresultswerecomparedwiththosefromthethree-discmultidentateelectrode.Thisdemonstrated,onanexperimentalscale,thattherotarymultidentatehelixelectrodewasbetterthanthemultidentatethree-discelectrodeastherewaslittleaccumulationofcoke,andtheC_2yieldperpasswas69.85%andC_2selectivityover99.14%with70.46%methaneconversionataninputpeakvoltageof2300Vand60ml/mingasflowrate.

简介：CO2photoreductionisanattractiveprocesswhichallowsthestorageofsolarenergyandsynthesisofsolarfuels.Manydifferentphotocatalyticsystemshavebeendeveloped,whilethealternativephoto-reactorsarestillinsufficientlyinvestigated.Inthiswork,photoreductionofCO2withH2OintoCH4wasinvestigatedinamodifiedconcentratingsolarreactor,usingTiO2andPt/TiO2asthecatalysts.TheTiO2andPt/TiO2sampleswereextensivelycharacterizedbydifferenttechniquesincludingpowderX-raydiffraction（XRD）,N2adsorption/desorptionandUV–visabsorption.ThecatalyticperformanceoftheTiO2andPt/TiO2samplesinthegasphasewasevaluatedunderunconcentratedandconcentratedXe-lamplightandnaturesolarlightwithdifferentconcentratingratios.VariousparametersofthereactionsystemandthecatalystswereinvestigatedandoptimizedtomaximizethecatalyticperformanceofCO2reductionsystem.Comparedwiththenormallightirradiation,theTiO2andPt/TiO2samplesshowhigherphotocatalyticactivity（about6–7times）forreducingCO2intoCH4underconcentratedXe-lamplightandnaturesolarlight.Intherangeofexperimentallightintensity,itisfoundthattheconcentrationofthelightmakesitsuitableforthecatalyticreaction,andincreasestheutilizationefficiencyoftheTiO2andPt/TiO2sampleswhiledoesnotdecreasethequantumefficiency.

简介：摘要：由于甲烷是导致温室效应的主要气体之一，对人体有害且有毒，因此甲烷的排放越来越受到社会的关注。在这种环境下，工业上已经严格控制了低温甲醇法应用中二氧化碳排放气体中的甲烷含量。希望通过有效控制甲烷含量，保证该工艺的长期、绿色应用，在现代化生产中发挥更大的作用。

简介：为提高气体机稀薄燃烧时的燃烧性能,解决天然气发动机在稀薄燃烧情况下点火能量高以及火焰传播速度慢的问题,提出利用强氧化性的臭氧对燃料进行改质,进而提高天然气燃烧性能的思路。通过Chemkin软件研究臭氧添加对甲烷滞燃期的影响,并对改善燃烧的化学机理进行了初步探索。试验结果表明添加臭氧后,某些重要基元反应的温度敏感性、自由基和中间物质的浓度和出现时间发生较大变化,进而改善了甲烷的点火特性。

简介：一个壶实验被执行在在栽培变种，超级米饭变化Ningjing1和传统的变化Zhendao11，它当前是商业地在南京使用了的二米饭之间的植物生产率和CH4排放学习差别，中国。CH4排放流动和土壤答案CH4内容的类似的季节的变化在测试栽培变种之间被发现。尽管在在栽培变种之间的植物生物资源生产没有重要差别，Ningjing1的谷物收益在35.0%是显著地更高的(P<0.05)与比Zhendao11，而从Ningjing1的全部的CH4排放是，35.2%降低(P<0.05)。在在栽培变种之间的CH4排放的数量的主要差别从tillering阶段发生在时期到出发阶段。可伸缩生物资源、可伸缩收益的CH4排出物是分别地为Ningjing1的3.8和5.2mg/g，显著地为Zhendao11比那些降低(7.4和12.8mg/g，分别地)。根据在植物生长特征和CH4排放之间的关系，一个更强壮的根系统主要作出贡献到Ningjing1的更低的CH4排放，作为与Zhendao11相比。我们的结果证明超级米饭不仅在谷物生产率而且在CH4排放缓解有优点。收割的超级米饭的进一步的扩大将在中国提高米饭收益和还原剂温室气体排放。

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简介：CrystallineTiO2（P25）andisolatedtitanatespeciesinaZSM-5structure（TS-1）weremodifiedwithAuandAg,respectively,andtestedinthegas-phasephotocatalyticCO2reductionunderhighpurityconditions.Thenoblemetalmodificationwasperformedbyphotodeposition.LightabsorbancepropertiesofthecatalystsareexaminedwithUV–Visspectroscopybeforeandaftertheactivitytest.Inthegas-phasephotocatalyticCO2reduction,itwasobservedthatthecatalystswithAgnanostructuresaremoreactivethanthosewithAunanostructures.Itisthusfoundthattheenergeticdifferencebetweenthebandgapenergyofthesemiconductorandthepositionoftheplasmonisinfluencingthephotocatalyticactivity.Potentially,plasmonexcitationduetovisiblelightabsorptionresultsinplasmonresonanceenergy,whichaffectstheexcitationofthesemiconductorpositively.Therefore,anoverlapbetweenbandgapenergyofthesemiconductorandmetalplasmonisneeded.

简介：本文针对煤层气中甲烷分子间作用是否影响煤层气吸附的问题，采用量子化学方法，在MP2／6—311G＋＋（3af，3pd）电子相关校正水平上，对cH4二聚体可能存在的十二种几何构型进行全自由度能量梯度优化和频率验证，对两种较稳定构型进行了基组叠加误差校正，并对这两种构型进行了振动频率和电荷分析，求得甲烷二聚体的离解能为1．81kJ·mol^-1，从而说明甲烷二聚体是弱结合分子，由此本文为煤层气吸附理论的完善提供了一定的理论依据。

简介：植物排放甲烷（CH4）的来源尚存很大争议，而光照和紫外辐射胁迫可能是植物排放CH4的重要影响因素．本研究选择亚热带常见树种米槠、木荷、浙江桂、罗浮栲、杉木、马尾松和柑橘7种树木为研究对象，利用控制实验研究了光照和增强紫外辐射对树木叶片CH4排放的影响．结果表明：7种树木叶片的平均CH4排放速率在光照条件下（21.176ng·CH4·g^-1DW·h^-1）是在黑暗条件下（9．699ng·CH4·g^-1DW·h^-1）的2．2倍，光照对不同树木叶片CH4排放速率的影响具有显著差异；在高UV-B辐射强度处理下，除浙江桂和柑橘外，其他5种树木的CH4排放速率均显著高于低UV—B辐射强度处理的CH4排放速率；树种及其与光照或UV辐射的交互作用对树木叶片CH4排放速率的都具有显著影响，光照或增强UV辐射强度对排放速率较低的树木种类排放CH4的促进作用更强．

简介：RE-dopedNi-basedcatalystswerepreparedbysol-gelmethod.ThesecatalystswereappliedtothereactionofCO2reformingCH4tosyngas.ThestudiesrevealthatRE-doped(RE=La,Ce,Sm,Yb)Ni-basedcatalystsshowhighercatalyticactivitythanundopedNi-basedcatalyst,andwiththeincreasingofRE-dopedquantity,thecatalyticactivityofcatalystsexhibitsregularchanges.WhenRE-dopedquantityis0.2%(molarratio),thecatalystsshowthebestcatalyticactivity.