学科分类
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245 个结果
  • 简介:TheJiaozhouBayischaracterizedbyheavyeutrophicationthatisassociatedwithintensiveanthropogenicactivities.FourcoresedimentsfromtheJiaozhouBayareanalyzedusingbulktechnologies,includingsedimentarytotalorganiccarbon(TOC),totalnitrogen(TN),thestablecarbon(δ~(13)C)andnitrogen(δ~(15)N)isotopiccompositiontoobtainthecomprehensiveunderstandingofthesourceandcompositionofsedimentaryorganicmatterandfurthershedlightontheenvironmentalchangesoftheJiaozhouBayonacentennialtimescale.ResultssuggestthattheTOCandTNconcentrationsincreaseintheuppercore,havingindicatedaprobableeutrophicationprocesssincethe1920sintheinnerbayandthe2000sinthebaymouth.TheTOCandTNconcentrationsoutsidethebayhavealsochangedsince1916owingtothevariationofterrigenousinput.ConsideringTOC/TNratio,δ~(13)Candδ~(15)N,itcanbeconcludedthereisamixtureofterrigenousandmarineorganicmattersourcesinthestudyarea.Asimpletwoend-member(terrigenousandmarine)mixingmodelusingδ~(13)Cindicatsthat45%–79%ofTOCintheJiaozhouBayisfromthemarinesource.TheenvironmentalchangesoftheJiaozhouBayarerecordedbygeochemicalproxies,whichareinfluencedbytheintensiveanthropogenicactivities(e.g.,extensiveuseoffertilizers,anddischargeofsewage)andclimatechanges(e.g.,rainfall).

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  • 简介:4-hydroxy-4'-nitroazobenzene(NHA)and4-amino-4'-nitroazobenzene(DO3)werepreparedrespectivelyfromp-nitrophenylamineasaprecursorcompound.Twokindsofdopedorganic/inorganichybridnonlinearoptical(NLO)materialscontainingNHAandDO3weresynthesizedbySol-Gelprocess.ThepreparationandpropertiesoftwoNLOmaterialswerestudiedandcharacterizedbyFTIR,1H-NMR,UV-VIS,SEM,DSCandSHGmeasurements.TheresultsshowthatthemaximumdopingamountsofNHAandDO3intwodopedhybridNLOmaterialsare7.2(wt)%and11.3(wt)%respectively,andthecorrespondingsecond-orderNLOcoefficients(d33values)are2.91×10-8esuand6.14×10-8esu.TwodopedNLOmaterialshaverelativelygoodRTstability,after90daysatRTthed33valuescanmaintainabout85%oftheirinitialvalues,butafter10hat100℃canonlymaintainabout50%oftheirinitialvalues.Inthisreport,thereasonsforhigh-temperatureinstabilityofdopedmaterialswerediscussed,andthepossibleimprovementswerealsosuggested.

  • 标签: 合成 表征 溶胶-凝胶法 有机/无机混合物 非线性光学材料 4-羟基-4'-硝基臭氧苯
  • 简介:Effectsofcolumntemperatureandflowrateonseparationoforganicacidswerestudiedbydeterminingninelow-molecular-weightorganicacidsonreversed-phaseC18columnusinghighperformaceliquidchromatography(HPLC)withawavelengthofUV(ultraviolet)214nmandamobilephaseof18mmolL^-1KH2PO4buffersolution(pH2.1).Thethermalstabiltiyoforganicacidswasdeterminedbycomparingtherecoveriesoforganicacidsindifferenttemperaturetreatments.Therelationshipsbetweencolumntemperature,flowrateorsolventpHandretentiontimewereanalyzed.AtlowsolventpH,separatioinefficiencyoforganicacidswasincreasedbyraisingtheflowrateofthesolventbecauseofloweringtheretentiontimeororganicacids.Highcolumntemperaturewasunfavorablefortheseparationoforganicacids.Theseparatingeffectcanbeenhancedthroughreducingcolumntemperatureinorganicaciddeterminationduetoincreasingretentiontime.Highthermalstabilityoforganicacidswithlowconcentrationswasobservedattemperatureof40℃-45℃,SensitivityandseparationeffectoforganicaciddeterminationbyHPLCwereclearlyimprovedbyacombinationofraisingflowrateandloweringcolumntemperatureatlowsolventpH.

  • 标签: HPLC法 根渗出物 有机酸 测定条件
  • 简介:Thenanoparticlesγ-Fe2O3coatedwithsurfactants.DBS,STandCTAB.repsectively.weresynthesizedbymicroemulsionmethod.Thecoatedferricoxides.whichshowenhancednonlinearopticalpropertiescomparedwiththeirbulkcounterpart.wereprobedbyEXAFSinsolutionforms.Thex=-rayabsorptionspectraforFeKedgeweremeasuredatroomtemperaturebyhelpofsynchrotronradiationlightsource.Extendedx-rayabsorptionfinestructureanalysisshowsthatthecoatinglayersoforganicmoleculesinteractwithsurfaceatomsofnanopartices,theFe-Obondlengthwasextended.

  • 标签: 氧化铁 纳米粒子 涂层 有机活化剂 EXAFS
  • 简介:土壤有机物(SOM)的分解具有为在土壤和温度和潮湿被看作控制SOM分解的二个重要因素的土壤之间的公司2交换的重要性。在这研究,土壤样品在在东北中国在Changbai山上从753~2357m的5举起被收集,并且在不同温度下面孵化了(5,10,15,20,25,和30????ü

  • 标签: 土壤有机质 有机质分解 土壤水分 海拔梯度 土壤温度 长白山
  • 简介:TheEastAsianmonsoonsysteminfluencesthesedimentationandtransportoforganicmatterinEastAsianmarginalseasthatisderivedfrombothterrestrialandmarinesources.Inthisstudy,wedeterminedorganiccarbon(OC)isotopevalues,concentrationsofmarinebiomarkers,andlevelsofOCandtotalnitrogen(TN)incoreYSC-1fromthecentralSouthYellowSea(SYS).OurobjectivesweretotracethesourcesofOCandvariationsinpalaeoproductivitysincethemiddleHolocene,andtheirrelationshipswiththeEastAsianmonsoonsystem.Therelativecontributionsofterrestrialversusmarineorganicmatterincoresedimentswereestimatedusingatwo-end-membermixingmodelofOCisotopes.ResultsshowthatmarineorganicmatterhasbeenthemainsedimentconstituentsincethemiddleHolocene.Thevariationofterrestrialorganiccarbonconcentration(OCter)issimilartotheEASMhistory.However,thevariationofmarineorganiccarbonconcentration(OCmar)isoppositetothatoftheEASMcurve,suggestingOCmarisdistinctlyinfluencedbyterrestrialmaterialinput.InputsofterrestrialnutrientsintotheSYSoccurintheformoffluvialandaeoliandust,whileconcentrationsofnutrientsinsurfacewaterarederivedmainlyfrombottomwaterviatheYellowSeacirculationsystem,whichiscontrolledbytheEastAsianwintermonsoon(EAWM).Variationsinpalaeoproductivityrepresentedbymarineorganicmatterandbiomarkerrecordsare,ingeneral,consistentwiththerecentEAWMintensitystudies,thus,comparedwithEASM,EAWMmayplaythemainroletocontrolthemarineproductivityvariationsintheSYS.

  • 标签: sedimentary organic matter BIOMARKER East Asian
  • 简介:Distributionsandsourcesoftotalorganiccarbon(TOC)inseabedsedimentsandtheirimplicationsforhydrodynamicsareanalyzed,intheturbiditymaximumoftheChangjiangEstuary.EcologyecoenvironmentaleffectsofestuarywateronthecontinuouslyincreasingterrigenousorganiccarbonfromtheChangjiangRiverarealsoexploredthroughvariationsoforganiccarboncontentandwaterqualityindicators.Resultsshowthat,hydrodynamicsexertimportantinfluencesondistributionsoforganiccarbonintheturbiditymaximumofChangjiangEstuary.Fortheirredistributioneffectofterrigenousorganiccarbonwithinthemovinglayerinthewholeregion,variationsfromlandtoseaarenotindicatedbysurficialandverticalaveragevaluesofTOCandtotalnitrogen(TN)contentsincoresediment,aswellasorganicstablecarbonisotopesinsurfacesediments.However,onthelong-timescale,thetrendofterrigenousorganiccarbondecreasingfromlandtoseaisstilldisplayedbyvariationsofstablecarbonisotopicaveragevaluesbecomingheavierfromlandtosea.PreviousstudieshaveshownthathighcontentofChlacannotappearintheChangjiangEstuaryindespiteofadequatenourishmentsupply,becausephotosynthesisofphytoplanktonisconstrainedbyhighsuspendedsedimentconcentration(SSC).However,anareawithahighcontentofChlaoccurs,whichmaybecausedbyresuspendedbenthicalgaewithbottomfinegrain-sizesediments.TremendouspressuresareimposedontheenvironmentofChangjiangEstuary,becauseofultrophicationtrendsandspecialhydrodynamics.PhytoplanktonbloomareatendstoextendfromtheouterseatothemouthofChangjiangRiver.

  • 标签: 中国 长江入海口 有机碳 氮化物 同位素
  • 简介:parasitoidAsecodesmento(沃克,1839)(Hymenoptera:Eulophidae)是草莓叶甲壳虫Galerucellatenella(L.)的最重要的biocontrol代理人(翘目:Chrysomelidae)在北欧洲。这里,我调查了在器官的草莓种植园的自然寄生状态是否被其他的主人植物绣线菊属的灌木(Filipendulaulmaria)的存在影响,并且寄生状态率是否在不同年龄(6~79年)的种植园之间不同。我也调查了parasitoid窝尺寸,身体尺寸和性别比率是否在这域里在二主机植物之间不同。寄生状态是很低的(0%)在里面最新建立了种植园并且在草莓被种约20年了的地里增加了到一个高原(40%)或更长。如此的一个扩大殖民过程为商业栽培者是不能接受的。发现一个方法在年轻种植园催化parasitoid人口积聚将因此是合乎需要的。Parasitoid窝尺寸在从绣线菊属的灌木收集的甲壳虫是更大的,当身体尺寸和性别比率没在从二植物收集的parasitoids之间不同时。这些调查结果建议绣线菊属的灌木能出口parasitoids到附近的草莓地。尽管这是可能性,我没处于在孤立的草莓地和邻近绣线菊属的灌木看台的地之间的寄生状态率发现任何重要差别,显示本地植被的效果在寄生状态率上是小的。在最新确定的草莓种植园释放parasitoids可以是为快速比与绣线菊属的灌木杂种获得高寄生状态的更好的策略。

  • 标签: 寄生率 草莓 植被 生防 林龄 寄主植物
  • 简介:Inrecentyears,theconcernaboutenvironmentalprotectionisincreasingonaworldscale.MajormanufacturersofhomeappliancesandOAequipmenthaveintroducedso-called'greenprocurementschemes'forreducingenvironmentallyharmfulsubstancesinmanufacturingprocessandendproducts.Undersuchbackground,anewtypeofchromate-freeorganiccompositecoatedelectro-galvanizedsteelsheetwithhighconductivitywasdevelopedbyBaosteel,whichmeetstheEURoHSDirective(RestrictionoftheHazardousSubstances)andotherrelatedlawsandregulationsonenvironmentalsafety.Italsoprovidesexcellentsurfaceelectricalconductivity,corrosionresistance,fingerprintresistance,solventresistance,coatingadhesion,heatresistance,formabilityandotherspecialpropertiestomeetthedemandofmanufacture’sprocessofOAmachine.Comparedwithpreviouslydevelopedanti-fingerprintingcoatedelectro-galvanizedsteelsheet,thisnewlydevelopedproducthasagoodbalancebetweenhighcorrosionresistance(timeto5%whiterustinsaltspraytestis120hforflatpaneland72hforworkedpotion)andconductivity(surfaceelectro-resistivityinaccordancewithLOREASTislessthan0.1milliohm)duetothespecialdesignofcoating’sstructure.Besides,Italsoprovidesthepropertiesofgroundingandshieldingagainstelectromagneticwaves.Theevaluationofsurfaceperformancesofnewproductshowedthatitiscomparableorevenbetterthanthesimilarproducts.Currently,thenewlydevelopedproducthasbeencommercialized.Inthispaper,themajorpropertiesarediscussed,suchascorrosionresistance,surfaceelectricalconductivity,fingerprintresistance,solventresistance,coatingadhesion(ink/melaminealkydpaint),heatresistanceandformability.Furthermore,theapplicationisalsobrieflydescribed.

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  • 简介:Afieldtestwiththetraditionalrotationofpaddyrice/uplandcrop(wheat)wascarriedoutonapaddysoilderivedfromredearthtoelucidatetheeffectoforganicmanureonthephoshporusadsorption-desorptionbysoilanditsPavailability.Soilsamplesweretakenfromdifferenttreatmentsatricehavestingstageandanalysed.TheisothermaladsorptionofPbythesamplesfittedverywellwithLangmuirequation,andhence,theparametersintheequation,i.e.,maximumadsorption(qm),constantrelatedtobondingenergy(k)andtheirproduct(k×qm)couldbeusedasacomprehensiveindextocharacterizethepotentialPadsorptivityofthesoil.Organo-inorganicfertilizationandorganicmanuringcoulddecreaseqmandk,whilemineralPapplicationhadlittleeffectonthem.TheisothermaldesorptionofPwassignificantlycorrelatedwithinitiallyaddedandisothermallyadsorbedP.PartofPaddedwasfixed,whichrepresentedthePfixationcapactyofsoil,andorganicmanuringcouldobviouslylowerthePfixation,ThecontentofsoilavailablePhadasignificantnegativecorrelationwithqm,kandfixedP.ItisconcluedthatorganicmanurecouldincreasethePavailabilityofpaddysoilderviedfromredearthbydecreasingqm.k,maximumbufferingcapacity(MBC=k×qm)andfixationcapacity.

  • 标签: 红壤 水稻土 有机肥 磷吸附-解吸附作用 可利用性
  • 简介:Aneworganicsemiconductortartaricaciddopedsaltofemeraldinepolyaniline(PANI-C4H6O6)hasbeenobtainedbythemethodofoxidativepolymerizationofmonomericanilinewithammoniumpersulfateinacidicsolution.ThestructurewascharacterizedbyFourierTransformInfraredtechnique(FTIR)andX-raydiffraction(XRD).Thetemperaturedependencedcconductivityδdc(T)showsasemiconductorbehaviorandfollowsthequasionedimensionalvariablerangehopping(Q1D-VRH)model.Dataonδdc(T)arealsodiscussed.

  • 标签: 有机半导体 结构 酒石酸 聚苯胺
  • 简介:Inordertobetterunderstandthecompositionalandstructuralcomplexityofdissolvedorganicmatter(DOM)macromoleculesandprovidemechanisticinformationonthebindingofhydrophobicorganiccontaminants(HOCs)toDOM,wefractionatedlargeamountsoflakewaterintothreehydrophobicDOM-fractions.Thevariationofthepartitioningcoef?cients(KDOC)ofpyreneatdifferentpHlevelswasexaminedby?orescencequenchingtitration.Resultsshowthat,relativetothemorepolaracidicDOM-fractions,thehydrophobicneutralfractionexhibitsahighersorptionabilitytopyrene.Generally,thesorptionofpyrenetothethreehydrophobicfractionsisstronglypH-dependent.TheKDOCvaluesofpyrenegenerallyincreasewithdecreasingpHlevels,whichisespeciallyobviousinthesorptionofpyrenetothefulvicacidfractions,suggestingthatthebindingiscontrolledbyhydrophobicinteractions.Themechanismsunderlyingthebindingofpyrenetothehydrophobicfractionswerealsodiscussed.Ourdataarebene?cialtofurtherunderstandingthebindingofHOCstoDOMandhowithasbeenaffected,whichmayresultinmoreaccuratepredictionsofKDOC.

  • 标签: 疏水性有机污染物 溶解有机物 DOM 酸组分 pH值 分离
  • 简介:Inorganic-richgasshales,claymineralsandorganicmatter(OM)havesignificantinfluencesontheorigin,preservation,andproductionofshalegas.Becauseofthesubstantialroleofnanoscaleporesinthegeneration,storage,andseepageofshalegas,weexaminedtheeffectsofclaymineralsandOMonnanoscaleporedistributioncharacteristicsinLowerPaleozoicshalegasreservoirs.UsingtheNiutitangandLongmaxishalesasexamples,wedeterminedtheeffectsofclaymineralsandOMonporesthroughsedimentationexperiments.Fieldemission–scanningelectronmicroscopycombinedwithlow-pressureN2adsorptionofthesamplesbeforeandaftersedimentationshowedsignificantdifferencesinporelocationandporesizedistributionbetweentheNiutitangandLongmaxishales.NanoscaleporesmostlyexistedinOMintheLongmaxishaleandinclaymineralsorOM–claycompositesintheNiutitangshale.Thedistributiondifferenceswereattributedlargelytovariabilityinthermalevolutionandtectonicdevelopmentandmightaccountforthedifferenceingas-bearingcapacitybetweentheNiutitangandLongmaxireservoirs.Inthenanoscalerange,mesoporesaccountedfor61–76%oftotalnanoscaleporevolume.ConsiderablydevelopednanoscaleporesinOMweredistributedinabroadsizerangeintheLongmaxishale,whichledtogoodporeconnectivityandgasproduction.Numerousnarrowpores(i.e.,pores\20nm)inOM–claycompositeswerefoundintheNiutitangshale,andmightaccountforthisshale’spoorporeconnectivityandlowgasproductionefficiency.Enhancingtheconnectivityofthemesopores(especiallypores\20nmandthosedevelopedinOM–claycomposites)mightbethekeytoimprovingdevelopmentoftheNiutitangshale.ThefindingsprovidenewinsightintotheformationandevolutionarymechanismofnanoscaleporesdevelopedinOMandclayminerals.

  • 标签: NANOSCALE PORE CLAY MINERALS Organic matter
  • 简介:Basedonsimpleanalyticalequations,shortcircuitcurrentdensity(JSC)oftheorganicbulkheterojunctionsolarcellshasbeencalculated.ItisfoundthattheopticalinterferenceeffectplaysaveryimportantroleinthedeterminationofJSC;andobviousoscillatorybehaviourofJSCwasobservedasafunctionofthickness.Atthesametime,theinfluenceofthecarrierlifetimeonJSCalsocannotbeneglected.Whenthecarrierlifetimeisrelativelyshort,JSConlyincreasesattheinitialstageandthendecreasesrapidlywiththeincreaseofactivelayerthickness.However,forarelativelylongcarrierlifetime,theexcitondissociationprobabilitymustbeconsidered,andJSCbehaveswave-likewiththeincreaseofactivelayerthickness.Thevalidityofthismodelisconfirmedbytheexperimentalresults.

  • 标签: 微电子学 电路 电子密度 理论
  • 简介:迈阿密河里的沾染物的运输(佛罗里达,美国)有河水流的沉积由于他们在离开潜在的来源的区域的潜在的影响是一颗担心。五金属的累积侧面(作为,Cd,Hg,Zn,Pb)在迈阿密的地表的沉积,河在与谷物尺寸的关系被评估(从不到0.075 ;公里到6.3 ;公里)并且器官的内容。地表的沉积样品沿着河盆以及在海湾水里被收集。好沉积(<0.106 ;公里)与比0.850 大的沉积相比包含了乘Cd和Hg的层次的超过10和乘砷的层次的超过6;公里。Zn和Pb层次是在好沉积的超过10次(<0.106 ;公里)与那些相比,那比4.750 大;公里。Cd,Hg,和Zn层次与沉积的全部的器官的碳内容有重要关联。这显示在好沉积的Cd,Hg,和Zn有潜力除了与河水流要动员的潜力被使产生代射变化。解决粒子的速度的吉布斯的分析证明比0.5 小的粒子;公里能与河水流被搬运。在好沉积的重金属的层次(<0.425 ;公里)沿着河,床证明好粒子有趋势外面在河水流低、带的地点被动员并且积累到海湾。

  • 标签: 表层沉积物 重金属含量 有机质含量 迈阿密 运输 粒子