学科分类
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156 个结果
  • 简介:Weidentifytwointerrelatedbutindependentspeciesofmicrocrackswithdifferentoriginsanddifferentdistributions.Onespeciesistheclassichigh-stressmicrocracksidentifiedinlaboratorystress-cellsassociatedwithacousticemissionsasmicrocracksopenwithincreasingstress.Theotherspeciesisthelow-stressdistributionsofclosely-spacedstress-alignedfluid-saturatedmicrocracksthatobservationsofshear-wavesplitting(SWS)demonstratepervadealmostallinsiturocksintheuppercrust,thelowercrust,andtheuppermost400kmofthemantle.Onsomeoccasionsthesetwosetsofmicrocracksmaybeinterrelatedandsimilar(hence'species')buttheytypicallyhavefundamentally-differentproperties,differentdistributions,anddifferentimplications.TheimportanceforhydrocarbonexplorationandrecoveryisthatSWSinhydrocarbonreservoirsmonitorscrackalignmentsandpreferreddirectionsoffluid-flow.TheimportanceforearthquakeseismologyisthatSWSabovesmallearthquakesmonitorstheeffectsofincreasingstressonthepervasivelow-stressmicrocrackdistributionssothatstress-accumulationbefore,possiblydistant,earthquakescanberecognisedandimpendin~earthquakesstress-forecast.

  • 标签: crack-induced anisotropy fluid-saturate microcracks SHEAR-WAVE splitting
  • 简介:Bothmorphologicalcharactersandaportionofof28SrDNAsequenceswereusedtoidentifyingTomicusspecies.Thespecimenswereclassedintogroupswiththefollowingcharacters:1)granulesorpuncturesoninterstria2onthedeclivityoftheelytra;2)lengthoftheelytralinterstrialhairsandhairsarisingfrompunctures;3)arrangementofpronotalpuncturesandhairs.Thesecharacterscouldbeclearlyexaminedunderabinocularmicroscopeat30×magnificationandtheywereapplicableandvaluablefortheforestentomologiststoidentifyTomicusspecies.Thephylogenetictreeestablishedwithdifferencein28SrDNAsequenceofD2regionrevealedthatthespecimensofeachgroupidentifiedbymorphologicalcharacterswerealsogroupedtogether.Thegeneticdistancesofintra-species,inter-speciesandinter-genuswerenotoverlapped.Geneticdivergenceof28SrDNAwasalsousefulforidentifyingTomicusspecies.

  • 标签: Tomicus MORPHOLOGY KEY to SPECIES of
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  • 简介:在在东方的种类和土壤因素之间的植物种类和关系的分发Gurbantunggut沙漠的中央部分被学习提供更多的卓见进植物群并且越过沙漠的各种各样的部分在植被决定差别。双向簇分析证明在区域的植被能被划分成三个组,第一个组被灌木种类,Ephedraprzewalskii和草种类统治,主要在扁平的根据和轻轻的斜坡的区域的Carexphysodes;第二个组被C统治。physodes,Artemisiasongorica和A。主要沙沙丘和第三个组的斜坡上的xerophytica被灌木种类统治,主要沙沙丘的顶上的Haloxylonpersicum。在植物密度在之间没有差别组织1和2,但是在组3有重要减少。不到植被组3的土壤水比在其它,二个组根本玷污深度的低得多。EC,有机物,全部的P和可溶的Na,Ca和Mg与土壤水很同样变化了。正规通讯分析(CCA)令人满意地在区域估计了种类土壤关系。植物种类的分发强烈与水内容,有机物,EC和营养素的土壤因素被相关。在三把CCA斧子解释的种类出现的变化是大约70%,显示一些解释地点变量可以在我们的学习参数外面存在。土壤质地被建议在未来研究被包括改进CCA的解释。

  • 标签: 古尔班通古特沙漠 植物物种 中国 土壤因素 灌木树种 土壤水分
  • 简介:Aciladivaricata(Hinds,1843)andA.mirabilis(AdamsandReeve,1850)arecommonbenthicbivalvesinChina.Anumberofresearchershaveproposedthatthelatterspeciesisajuniorsynonymoftheformerspecies.Becauseofmorphologicalsimilarities,itisdifficulttodistinguishthesetwospeciesbasedonvisualexaminationonly.Forbetterunderstandingoftheirtaxonomy,themitochondrialCOIgenefragmentsoffiveindividualsofA.divaricatafromtheEastChinaSeaandsixindividualsofA.mirabilisfromtheYellowSeaweresequencedinthisstudy.ThephylogeneticrelationshipsoftheobtainedCOIsequences,togetherwithnineteensequencesofthreespeciesofthegenusNucula,wereanalyzed.Thepairwiseintra-andinter-specificdistancesfortheCOIsequencesrangedfrom0.002to0.017andfrom0.128to0.134,respectively,andnooverlapwasfound.Phylogenetically,A.divaricataandA.mirabilisformdistinctcladesandclusterintoasistertoallotherNuculaspecies.TheresultsindicatedthatA.divaricataandA.mirabilisaretwodistinctspecies.Thedifferencesinthemorphologyanddistributionbetweenthetwospecieswerebrieflydiscussed.

  • 标签: 线粒体 物种 杆菌 防风 DNA 系统发育关系
  • 简介:Nativetreesplayimportantrolesinurbanforestry,suchasadeepculturalbackground,astrongecologicaladaptability,ahighperformance-costratioandaconvenientmanagement.Butnowtherearesomedifficultiesinnativetrees'utilizationandpopularizationduetofewstudyonlandscapeplant.Inordertoseekanabnormalandartificiallandscapingandtoproduceaneffectiveresultassoonaspossible,nativeandforeignplantscanbeproperlyusedasanavailableresourcebyimprovingtheirtechnologicallevelandemphasizingnaturalbalance.ThenChineseclassiccultureandgreeneconomicscanbecombinedwithbeautifulforestrybyimplementingurbansustainabledevelopment.

  • 标签: 城市森林 城市生态系统 本土树种 生态适应性 中国
  • 简介:OnthebasisofaninvestigationonthemangrovesinFujianfromNovember1998toJanuary1999,thespeciescomposition,area,distribution,artificialafforestationofmangrovesandthefactorsrestrictingthedevelopmentofmangrovesinFujianarediscussedinthepaper.SomesuggestionsonhowtodevelopmangrovesinFujianhavebeenputforward.

  • 标签: Fujian mangroves distribution area afforestation INVESTIGATION
  • 简介:Inordertoexplorethefeasibilityofcryopreservationondormantforesttreeseeds,theseedviabilityof4species(Malusbaccata,Prunusdavidiana,P.armenicaandAmygdalupersica)withmoisturecontent(MC)changingwastestedafter30-daystorageinliquidnitrogenof-196℃.Theresultsshowedthatallthe4speciesofseedscankeepastableviabilityaftercryopreservation.Intheprocedure,theoptimumMCwas48g/kgforM.baccata,27g/kgforP.davidiana,31g/kgforP.armenicaand45g/kgforA.persica,...

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  • 简介:Theeffectsofheatlossonthestructureoflaminarflamelets,whicharetheconstitutiveelementsofturbulentflamesunderthemostcommonoperatingconditions,areinvestigatedfortypicalaeronauticalgas-turbineoperatingconditionsattake-off.Themagnitudeofheatlossisquantifiedviathe"enthalpydefect"measuredwithrespecttoanadiabaticflame.Aproceduretogeneratelaminarflameletswithanassignedenthalpydefectattheboundariesisdevisedandappliedtononpremixedpropane/airflames,aspropanereproducestheessentialfeaturesofhigherhydrocarboncombustion.Itisfound,contrarytocommonlyheldbeliefs,thattheenthalpydefecthasasignificanteffectontheconcentrationnotonlyofminorspecies,butalsoofmainreactionproducts.Sucheffectsarefoundingeneraltobemorepronouncedforfuel-richconditions.Animpactisanticipatedontheformationrateofnitricoxides.Theeffectsofscalardissipationratearealsodiscussed.

  • 标签: 火焰结构 热损失 浓度 物种 航空燃气轮机 层流火焰
  • 简介:TheaccumulationandabsorptionkineticsofLabyfish(Oryziaslatipes)frombothwaterandfoodweretestedinfreshwater.TheeffectsofLaconcentrationinwaterandfoodandtheexistenceoffulvicacidontheabsorptionwereinvestigated.ItwasdemonstratedthattheamountofLaaccumulatedinfishincreaseswiththeincreaseinLaconcentrationinwaterandfoodandexposureduration,whichthenormalphysiologicalactivityoffishwasinhibited.Withfulvicinthesystem,theabsorptionratedecreasessignificantlyindicatingthatthefulviccombinedLaisnotavailabletothefishuptake.

  • 标签: ORYZIAS Latipes 稀土 积累 吸收 动力学
  • 简介:ThebulbsofFritillariaspp.(Liliaceae)areusedinChinesemedicineasantipyretic,anti-tussive,expectorant,etc.Inordertosearchforthebioactiveconstituentsfromthisgenus,thebulbsoffourspeciesofmedicinalFritillariaplantshavebeeninvestigated.ThirteencompoundswereisolatedfromFritillariathunbergiiMiq.,threeofthemwerenewcompounds.FourteencompoundsfromFritillariathunbergiivar.chekiangensisHsiaoetK.C.HsiacollectedinDongyangofZhejiangProvince,fourofthemarenewcompoundsandanotheronewasfirstiso-

  • 标签: 贝母 浙贝母 化学成分
  • 简介:1.IntroductionGopalsamyandLadajs[1]illtroducedthefollowingdelayLotka-Volterratypesinglespeciespopulationgrowthmodel:wherea,b,ctTarerealconstants,anda>0,c>0,T20.Ifa>0,b<0andc=0,then(1.1)reducestotheLogisticequation.Ifb>0,(l.1)exhibitstheso--calledAlic...

  • 标签: Single species POPULATION growth POSITIVE PERIODIC
  • 简介:UrbanforestryisnowincreasinglypracticedinThailand.Thishasgainedimpetusbecauseofgradualdeteriorationofvisualamenityandenvironmentalqualityinmanyoftherapidlydevelopingurbancenters.Variousurbanbeautificationprogramsarebeingimplementedtorehabilitateblightedlandscape,pollutedatmosphereanddeterioratingweatherconditions,aswellastomaintainaclean,healthyandpleasantenvironmentsoastoensureabetterqualityoflife.Plantingofsuitabletreesforshade,climaticameliorationandaestheticvaluesformtheprincipalactivityunderthesebeautificationprograms.Itisregardedasnotonlyanimportantcomponentofsocio-economicdevelopmentbutalsocontributivetotherestorationoftheurbanecosystem.TheresponsibilityoftheimplementationofmostoftheseprogramsfallstotheBangkokMetropolitan,Administration,ProvincialandDistrictMunicipalities.TheRoyalForestDepartmentplaysthesupportingroleofsupplyingseedlingsofthespeciesrequiredforplantingandprovidingtechnicaladviceonthegrowingofthesetrees.InthispapertreespeciescommonlyplantedinurbanandpopulatedareasinThailandareidentified.ItisenvisagedthatwiththevastamountoffloraavailableinThailandandthroughtheintegratedeffortsofallagenciesinvolved,thisprogramwillachievethetargetofbeautifyingthecitiesandtownsofThailand.

  • 标签: 泰国 城市森林 城市绿化 植树造林 城市生态环境
  • 简介:FurnitureofHongmu,creamofChineseculture,hasalonghistoryandenjoysgreatpopularityforitsclassicappearanceandelegantdisposition.Thetraditionalmethodoftheidentificationistoevaluatethemacroformandanatomicalfeatures.Inthispaper,anewmethodbasedonthedifferencesamongthechemicalcharacteristicsofbiologicalmetabolitesofsamplesisdeveloped.Intheresearch,highperformanceliquidchromatography(HPLC)fingerprintswereemployedtodiscriminatefourspeciesofHongmu,includingPterocarpusindicus,Pterocarpusmacarocarpus,Dalbergiamelanoxylon,andDalbergialouvelii.Theresultsshowedthat,accordingtotheretentiontimeandrelativepeakareaofdifferentcomponentsinwoodextracts,thedistinctioncanbeeasilymadebetweendifferentspecies.BasedontheHPLCfingerprints,similaritiesbetweensampleswereevaluatedbycorrelationcoefficients.Theresultsweregreaterthan0.81betweenthesamespecies,andlessthan0.21betweendifferentspecies,whichshowedweakcorrelationbetweendifferentspecies.Inordertoestimatetheoverallfeaturesofthefingerprints,hierarchicalclusteringandprincipalcomponentanalysis(PCA)wereusedandtheresultsshowedpronouncedclusteringeffectamongthesamespecies.TheinvestigationindicatedthatpatternrecognitioncouldaccuratelyreflectthesignificantdifferencesbetweendifferentspeciesofHongmu,andcanbeusedasareferenceforqualitycontrol.

  • 标签: Hongmu IDENTIFICATION HPLC FINGERPRINT pattern RECOGNITION
  • 简介:Fromaworld-wideplantintroductiontrialseriesutilising25centralAmericanspeciesplantedatover100sitesinnearly60countries,eighteenspeciesplantedat15sitesinthetropicswerechosenforfurtherstudyofthefactorsdeterminingsiteproductivityandsitebyspeciesinteractions.ThespecieswereAcaciapennatula,Acaciafarnesiana,Albiziaguachapele,Ateleiaherbert-smithii,Caesalpiniacoriaria,Caesalpiniaeriostachys,Caesalpiniavelutina,Enterolobiumcyclocarpum,Gliricidiasepi...

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  • 简介:ChemicalanalyseswereconductedwithleaveoilsofEucalyptussmithii,E.bakeri,E.polybractea,E.dives,E.radiataandE.macarthuriivvhichwereintroducedtosouthwesternChinafromAustralia.ItwasfoundthattheleafoilsofE.smithii,E.bakeriandE.polybracteacontained81-90%of1,8-cineole,andE.divesandE.radiatacontainedhighera-phelandreneandpiperitone.Therevveresignificantinter-andintraspeciflcvariationsinleafoilyield,italsovariedwithseasonsinvvhichleaves...

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  • 简介:马尾藻类海草的种类全球被散布,并且具有在海洋的生态系统和bioresources的大生态、经济的重要性。在这研究,六马尾藻类海草种的transcriptomesequencings用一个Illumina平台第一次被执行。为每件样品,核苷酸的2.12.5Gb的一个总数进69871116790脚手架镇定、装配,与410550bp的平均长度和7561462bp的N50长度。每件样品的2051228684unigenes的一个总数从nr数据库与已知的基因序列被注解并且比较很好。Orthologous组(轮牙)的簇,基因本体论(去)并且分析也是的基因和染色体(KEGG)的京都百科全书为基因功能和规定小径的进一步的理解表现了。基因表示层次基于RPKM价值是计算的并且在这些之中比较了种类,特别为与糖类新陈代谢有关的那些基因。聚类显示的分析在S之间的全球基因表示的差别。fusiforme,它以前作为Hizikiafusiformis被提名,和另外的五种不是重要的。108orthologous基因的进一步种系发生的分析证实了那S。fusiforme与S有更靠近的关系。hemiphyllum而非S。horneri。这些transcriptome数据在未来研究为染色体的更好的理解和马尾藻类海草水藻和受益比较级和Phaeophyceae种类的种系发生的研究的基因特征提供了珍贵信息。

  • 标签: 转录组 马尾藻 测序 海洋生态系统 基因表达水平 基因功能