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:【摘要】本文分析了影响小盒透明纸侧封质量的因素,阐述了对小盒透明纸侧封质量的改进方法,同时给出了技术要求,并得以推广到其他现有设备中,取得了良好的效果,外观质量得到很大改善。
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.
简介:本文探讨(CH3Li)4中键的作用,通过计算,发现(CH3Li)4分子的面甲基结构比顶甲基结构要稳定;指出Li—Li间的成键作用相当强,约为Li2分子中键作用的40%左右,估计(CH3Li)4中的J7Li-6Li值约为1Hz。
简介:Anewμ3-Otriiron(Ⅲ)complex[Fe3O(OBz)6(CH3OH)3](NO3)(CH3OH)2(HOBZ=benzoicacid)hasbeensynthesized,itsstructurehasbeendeterminedandvariabletemperaturemagneticsusceptilityhasalsobeenmeasured.Inthemolecule,threeironatomsformedanequilateraltrianglewithu3-Oincenter.ThefittingtothemagneticsusceptibilityshowedthatanintramolecularantiferromagneticexchangeinteractionoccurredbetweenironatomswithJ=-25.51cm-1,andaweakerintermolecularantiferromagneticexchangeinteractionoccurredwithzJ’=-2.30cm-1.
简介:ThecrystalstructureofDi-nitratobis(ethylcaprolactam)uranyl(Ⅱ)UO2[CH2(CH2)4CONC2H5]2(NO3)2wasestablishedbyasingle-crystalX-raydiffractionstudy.Itistriclinie,spacegroupP1,witha=7.171(2),b=8.655(3),c=10.182(5)A,α=78.27(3),β=70.63(3),γ=81.76(3)°,V=581.7(4)A3,Z=l,Dc=1.94g.cm-3.FinalRvalueis0.0218.Theresultrevealsthaturanylioniscoordinatedtosixoxygenatoms,twoofthemarefromtwocarbonylgroupsofethylcaprolactamandtheotherfourarefromtwonitrategroups.