简介:Sand-duststormisaspecialnaturaldisasterthatfrequentlyoccursindesertsandtheirsurroundingareas.WiththedatapublishedonSurfaceMeteorologicalMonthlyBulletinandSurfaceChartduring1971-1996,thetemporal-spatialdistributionandannualvariationofsand-duststormsareanalyzedonthebasisofthecasestudyofatmosphericprocesses.Furthermore,thetracksandsourceareasofsand-duststormsaredeterminedwiththeaidofGIS.TheresultsshowthatexceptsomepartsofQinghaiProvinceandInnerMongoliaaswellasBeijing,sand-duststormsdecreaseapparentlyintimeandspaceinrecentdecadesinChina.Sand-duststormsoccurmostfrequentlyinspring,especiallyinApril.Accordingtotheirsourceareas,sand-duststormsareclassifiedintotwotypes,i.e.,theinner-sourceandouter-sourcesand-duststorms.Mostoftheouter-sourcesand-duststormsmovealongthenorthandwesttracks.Thenorth-trackouter-sourcesand-duststormsalwaysintrudeintoChinaacrosstheSino-MongolianborderfromHami,acityintheeasternpartofXinjiang,toXilinGol,aleagueinInnerMongolia,whilethewest-trackonesintrudeintoChinafrombothsouthernandnorthernXinjiang.Thesourcelandsofinner-sourcesand-duststormsconcentrateintheTaklimakanDesertanditssurroundingareasinsouthernXinjiang,southernpartoftheJunggarBasininnorthofXinjiang,theHexiCorridorinwesternGansuProvince,thedrydesertsofInnerMongoliaandtheQaidamBasininQinghai.
简介:暴风雨(SDS)天气从1980~2011在东北亚洲上处理的地区性的沙灰尘的典型分布用气象学的数据,大气的发出声音数据,中国高密度天气数据,NCEP/NCAR分析数据,以及转存的原版捱过的分享的世界气象组织表面车站被调查中国的地图。集中加权的轨道(享特威)方法被用来从分离车站数据计算SDS频率并且在东北亚洲追踪大规模地区性的SDS天气进程。一个花键趋势分析方法被采用调查SDS天气系统的可变性。结果证明在19802011期间,SDS天气过程与近似10年的高度低的出现摆动展出历史的坚持和突然的转变。通过大气的循环的合成分析在高、低的SDS年期间,SDS出现是,这被发现仔细与北极旋涡和midlatitude的异例有关西,并且在湖贝加尔湖附近的发行量模式。在高频率年期间,meridianal在东亚在高SDS走廊上面流动在上面、中间的对流层(从沿着西北和诺思中国,朝鲜半岛,和日本岛的巴尔克哈什湖)比meridianal流动在低SDS频率年期间的显然强壮,在midlatitude区域赞成SDS的发展和运输。
简介:Therelationbetweengrain-sizedistributionofthebedandinsuspensionwascriticallyexaminedunderauniformflowvelocityof50cm/sovertwobeds:oneofmainlyfinesandsandtheotherofmediumsands.Twosections-one2.85mdownstreamandtheother6.35mdownstreamintheexperimentalchannel-wereselectedforsamplingtostudythegrain-sortingpatternintheverticaldirectionalongthedirectionoftransport.Theshapeandtypeofthegrain-sizedistributionpatternwerecriticallystudiedwithheightabovethebed.Thechangeinthedistributionpatternhasbeenattributedtothechangeoflocalbedroughnesscausingscouringagainsttheprotrudedrelativelycoarsegrainsonthebed.Suchtrendsareimportanttopredictthenatureofriverbedtopography.ThesandofBed-1initiallyexhibitsalog-skew-Laplacedistributionatdifferentheightsofsuspension.Thedistributionpattern,however,changesbutthischangingpatternisnotconsistentalongtheupstreamside.ForBed-2,whichinitiallyexhibitsalog-normaldistribution,thesamepatternpersistsfromtheheightofsuspensionat5cmupto20cm.Suchconsistencyinlog-normalityisalsoobservedatthedownstreampointsofmeasurement.Itisgenerallyexpectedthatthemeangrain-sizewouldreducewithincreasesofsuspensionheightbuttheresultsoftheexperiments,insomeoccasions,differsignificantlyfromthegradualfiningupwardtrend.Thisresulthasbeenattributedtolocalchangesofbedroughnessarisingfromtheprotrudedrelativelycoarsegrainscausingeddies,scouring,andturbulentphenomenawhichmovescoarseparticleshigherinsuspensionaddingacoarsetailtothedistributionincreasingthemeangrain-size.
简介:沙的荒芜的风景处于自然条件是干旱气候和丰富的沙材料供应的一个地质的产品,因此沙的沙漠的形成是为理解在地球系统的各种各样的stratigraphic/epigenetic范围之间的相互作用的一个理想的学习目标。直到现在,然而,这些的起源和形成的知识在Xinjiang抛弃,中亚多样、不一致,系统的评论是必要的。在在包围Xinjiang沙漠的新生代阶层的这些沙漠和他们的成双的灰尘存款的内部区域的古老的风神的沙沉积是反映沙漠的沙材料和形成和进化的起源的直接、间接的线索。在外部区域基于geochemical,荒芜的沙的矿物学、同位素的证据和相关存款,这篇论文在Xinjiang在沙的沙漠的发展考察研究进步,西北中国。许多证明建议在Xinjiang的荒芜的沙主要从古老的雨、冲积、河的沉积被采购并且因为本地沙供应,最后被完成。它指出在Xinjiang的构造结构的设置在Tarim盆和被地区性的水文学系统极大地影响的Junggar盆使沉积成为了两个,风神的进程从行星的风系统发源西,东方亚洲冬季季风和地形学的山脉山谷弯屈。然而,交通路径的方向在水文学动力学和风神的动力学之间是不同的,分别地,它被盆tectonics和地区性的大气的发行量线路的倾斜的结构决定并且决定了不同代理人交付的这些沉积的运输小径的anisotropies。这在二大盆导致由岩屑形成的沉积交通的一个地质的周期并且大部分因此增加沉积混合的度,引申并且在沙起源的更年轻、更旧的沉积来源,以及复杂性和差异之间再循环。
简介:Theformationofsandwaveissuchaprocessinwhichtheroughnessanddiscontinuityoftheoriginalbedsurfacecausethedisturbanceofthebottomlaminarflowinanopenchannel,andthedevelopmentofthedisturbanceinturnleadstoinstabilityoftheflowandtheappearanceofthecoherentstructure.Theevolutionanddevelopmentofthecoherentstructurefurtherpromotetheundulationsofbedsurfaceandsandwavesrisefinally.Thesandwaveisexplainedasaresultofactionthatthebedsedimentparticlesaredisturbedbythecoherentstructure.Thisstudyshowsthatthesandwaveformationistheresultofdisturbanceactionofneutralcoherentstructure,andthesandwaveshapeobtainedincomputationsisidenticaltothepracticalone.
简介:FieldexperimentswereconductedontotalloadtransportintheChelichayRiverBasin,amountainouscatchment(1,400km~2)locatedinnortheasternofIran,toevaluatetotalloadformulasincludingfourgravelbedriversandasandbedriver(QaresooRiver).GravelbedriversinChelichayRiverBasincanbegroupedintotwotypes;steepsloperiverswithhighshearvalues(ChehelchayRiverandKhormalooRiver)andmildsloperiverswithlowshearvalues(NarmabRiverandSoosaraRiver).Twodepthintegratingsuspendedloadsamplers(DH-48andD-49),andtwobedloadsamplers(Helley-SmithandBLSH)wereusedtomeasuretotalload.Theperformanceistestedof8totalloadtransportformulaeincluding4macroscopicand4microscopicmethods.Asystematicandthoroughanalysisof59setsofdatacollectedfromsandbedriverindicatethatYangandEngelundandHansenreachtothebetterresults,andfromfourgravelbedriversconfirmedthatthemethodsofKarimandKennedyandEngelundandHansenyieldsthebestresultsforsteepsloperivers,andthemethodsofEinsteinandBijkerarerankedhighestingradualsloperivers.
简介:AbstractBackground:As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD). This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs.Methods:A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species.Results:Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) while kdr mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed.Conclusions:Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.
简介:ThemainpurposeofthisstudyistoputforwardareasonableideaofthegeneralprotectionforSingingSandMoun-tainandCrescentMoonSpring,arareanduniquedesertwonder,andofsustainabletourismdevelopmentbasedontheresearchontheecologicalenvironmentaround.Methodsofdocumentation,casestudyandcomparisonwereemployed.Finally,aimingatsolvingtheproblemsofnaturalenvironmentandthoseexistingaftertheexploitationofSingingSandMountainandCrescentMoonSpringtheauthorputsforwardthreemeasures:thecom-prehensivetreatmentforCrescentMoonSpring(broadeningre-sourcesofwaterandreducingexpenditures,checkingthede-creasingdepthofCrescentMoonSpring,andimprovingthegeo-graphicalenvironment),thegeneralprotectionenvisionsforSingingSandMountainandCrescentMoonSpringandestablish-ingadynamicmonitoringandearly-warningsystemofregionalecosystem.
简介:充满沙的骚动杯被用来在东南中国的潮湿的画热带学习降雨和throughfall的腐蚀力量。骚动杯大小在田野条件和森林植被下面产出精确、可再现的结果。骚动杯暴露于不同年龄的特定的森林看台并且到选择种类(Schimasuperba,Castanopsiseyrei,Daphniphyllumoldhamii,Lithocarpusglaber)在Gutianshan()国家自然保护区(GNNR)。在throughfall的腐蚀力量掉与田野相比高2.59倍的森林植被表演中的大小的结果。这在森林生态系统加重灌木,植物和崽层的重要性保护土壤免于侵蚀。从叶子和分支的联合落下(滴下)尽最大努力为这著名获得负责。而且,在在调查的树种类之间的sandloss的差别(脱落,常绿树)表明侵蚀潜力和throughfall的空间异质是种类特定的。这强调就土壤侵蚀的预防而言为造林工程选择特定的种类的重要性。
简介:Principalstressaxesrotationinfluencesthestress-strainbehaviorofsandunderwaveloading.Aconstitutivemodelforsand,whichconsidersprincipalstressorientationandisbasedongeneralizedplasticitytheory,isproposed.Thenewmodel,whichemploysstressinvariantsandadiscretememoryfactorduringreloading,isoriginalbecauseitquantifiesmodelparametersusingexperimentaldata.Foursetsofhollowtorsionexperimentswereconductedtocalibratetheparametersandpredictthecapabilityoftheproposedmodel,whichdescribestheeffectsofprincipalstressorientationonthebehaviorofsand.Theresultsprovetheeffectivenessoftheproposedcalibrationmethod.
简介:Thehydrothermalreactivityofsilicasandwasstudiedusingcementkilndust(CKD)asanactivatorinadditiontothePortlandcementfractionofEl-Karnakcement(ablendofordinaryPortlandcementandgroundsand).AutoclavedEl-Karnakcementpasteswerestudiedatpressuresof0.507,1.013and1.520MPaofsaturatedsteamwithrespecttotheircompressivestrength,kineticsofhydrothermalreactionandthephasecompositionoftheformedhydrates.TheroleofCKDinaffectingthephysicochemicalandmechanicalpropertiesofEl-Karnakcementpasteswasstudiedbyautoclavingofseveralpastescontaining5,7.5,10and20%CKDatapressureof1.013MPaofsaturatedsteam.CKDwasaddedeitherasarawCKD(unwashed)orafterwashingwithwater(washedCKD).TheresultsofthesephysicochemicalstudiesobtainedcouldberelatedasmuchaspossibletotheroleofCKD(raworwashed)inaffectingthehydrothermalreactivityofsilicasandinEl-Karnakcementpastes.
简介:在中国的江苏海岸定位的光线的沙山脉系统(RSRS)为它的特殊结构和潜在的陆地资源在它形成的起源和技工上吸引许多注意。由于复杂水动力学状况,江苏RSRS是一热在它的潜在的来源,长江或黄河上辩论了吗?我们在夏天从现代黄河河口沿着Bohai海和黄海的西方海岸从表面沉积收集了十件沙样品到长江河口,2013。样品被由岩屑形成的锆石年龄的方法为RSRS沉积的来源鉴定分析。样品的由岩屑形成的锆石谷物的U-Pb年龄系列从新生代显示出一个宽范围到与几座年龄山峰晚太古代。比较在长江和黄河之间的年龄系列,由岩屑形成的锆石有更年轻的年龄(<100妈)在长江的组。江苏沿海的RSRS沉积的这些年龄分发类似于长江的,但是与黄河不同。邻近旧黄河三角洲的定位的样品显示出更宽范围的年龄分发,暗示来自两条河的加重的起源。把调查结果基于这些与普通意见相反,江苏RSRS的主要沉积来源是长江,而非黄河,这被建议。由牵连,应该有海洋的水流和潮汐的运动的水动力学力学的证据。这个方面在未来研究等候证实。
简介:Thewide-shallowcompositebucketfoundation(WSCBF)isanewtypeofoffshorewindpowerfoundationthatcanbebuiltonlandandrapidlyinstalledoffshore,therebyeffectivelyreducingtheconstructiontimeandcostsofoffshorewindpowerfoundation.Inthisstudy,thehorizontalbearingcapacityiscalculatedbyfiniteelementsimulationandcomparedwithtestresultstoverifythevalidityofresults.Inthisprocess,theverticalloadandbendingloadarerespectivelycalculatedbythefiniteelementsimulation.Undertheverticalloadeffect,thebucketfoundationandthesoilinsideareregardedasawhole,andthecorrespondingbucklingfailuremodeisobtained.Theultimateverticalbearingcapacityiscalculatedusingempiricalandtheoreticalformulas;thetheoreticalformulaisalsorevisedbyfiniteelementresults.Underbendingload,therotationalcenterofthecompositebucketfoundation(inaregionclosetothebucketbottom)graduallymovesfromtheleftofthecentralaxis(reversetoloadingdirection)tothenearbycompartmentboardsalongtheloadingdirection.TheH–Menvelopelineshowsalinearrelationship,anditisdeterminedthattheverticalandbendingultimatebearingcapacitiescanbeimprovedbyanappropriateverticalload.
简介:在一些液化的沙存款的加速记录展出特殊尖刻的波形,由强壮的扩大和高周波的部件描绘了。一个全面组成的模型被用来分析如此的尖刻的加速回答的机制。一个理想化的single-degree-of-freedom(SDF)系统被构造,在哪个春天的力量排水量关系在砍的undrained期间跟随浸透的沙的压力紧张行为。SDF系统证明尖铁是直接与沙的变硬紧张的行为有关在液化以后的周期的砍期间。而且,在那里存在阀值砍拉紧长度,它根据有限振幅像液体砍产生在的紧张即时在液化以后的阶段期间州的零个有效压力。当时,尖刻的加速能仅仅发生周期砍紧张超过阀值砍紧张长度。因为,在加速尖铁之间的时间间隔与摇晃的继续一起逐渐地增加,这也被揭示因为阀值砍紧张长度增加逐渐地然后更,时间被需要产生更大砍引起紧张变硬的紧张。在Kushiro港口地点和港口岛地点的记录通过充分联合的方法在过去的地震期间被模仿验证介绍机制。
简介:控制desertification是为中国的Qinghai西藏高原的一个重要生态的目标,在沙的土壤改进上的植被恢复措施的影响上的研究仍然正在缺乏的地方。在Guinan县的Mugetan沙漠,Qinghai省,东北Qinghai西藏高原是一个代表性的生态的恢复区域。生态的恢复和它的性质上的人工的植被的影响被使用包括表面层的内容和植被作文测试的领域调查和样品学习活动,修理半,并且固定的沙沙丘。结果证明苔藓外壳在变得在人工的植被的影响下面在30年以后修理了的一个沙沙丘的表面上形成了(即中国白杨)。同时,泥土矿物质,有机物,和其它玷污可得到的营养素显著地增加了。关联在这些材料之间被发现了,即,与淤泥和泥土增加的泥土矿物质和有机物内容在沙内容与减小增加。另外,土壤营养素断然随植物diversity.Under的增加被相关当前的气象学的条件,人工的植被在Mugetan沙漠对沙沙丘和生态的恢复的稳定有用。
简介:Thecoal-bearingstrataoftheUpperPaleozoic(fromtheTaiyuanFormationtothelowermemberoftheShanxiFormation)arethemostimportantunitsthathavehighgasproductionintheDaniudigasfield,whichisatypicaltight-sandstonereservoirwithhighheterogeneityintheOrdosBasin,China.Basedonanintegratedinvestigationofwelllogs,cores,SEMand3-Dseismicdata,wedelineatedthesedimentaryfaciesofthecoal-bearingstrataanddividedthesuccessionintosequencedstratigraphicunitsofdifferentdepositionalsystems.AsedimentaryhiatuswasdocumentedforthefirsttimeinthestudyareaandformsthesequenceboundarybetweentheLowerPennsylvanianCarboniferousTaiyuanFormation(Ct1)andtheUpperPennsylvanianCarboniferousTaiyuanFormation(Ct2).Thecoal-bearingstratainCt1areindicativeofabarriercoastaldepositionsystem.Tidalchannelsareidentifiedbytheirfine-grained,cross-stratifiedcharacter.Thesandsinthetidalchannelsarewellsorted,andthequartzcontentisabove95%.Thecoalbedlocatedbesidethesandstoneisthoughttobealagoon.Gas-bearing,coarse-grainedsandstoneinthecoal-bearingstrataspanningfromtheCt2tothelowermembersoftheShanxiFormation(P1s)isinterpretedasafluvial-dominatedbraideddeltathatisdividedintofourthird-ordersequences.Thecoal-bearingstrataarecomposedofsandstone,mudstoneandcoalbedfrombasetotopineachsequence.Braided-riverdepositsformthelowstandsystemtract(LST)withineachsequence.Ashelfandlakedepositionalenvironmentcontainingdarkgraymudstoneformsthetransgressivesystemstract(TST).Thehighstandsystemstract(HST)depositsformtheswampcoalbedineachsequence.
简介:Acoupledroutingforthetransportcapacityandtheenergyslopeisintroducedthroughthedefinitionofthecontrolfactormwhosevalueislinkedtothebedformconfiguration.Thecouplingaimstofurtherincorporatetheinteractionsoccurringinalluvialriversandthusenhancethepredictionofthefinesedimentfluxes,especiallyduringhighstreampowerevents.Basedonapredictiveruleforthecontrolfactormthatonlyinvolveswaterdepth,velocityandbedformconstitutivetexture,thenovelmethodisconfrontedtoobservationscollectedinoneofthemoststronglydynamicalluvialrivernamelytheLowerYellowRiver.Comparisonsbetweentimeseriesofmeasuredandcomputedconcentrationsillustratethatduringhighvelocityeventsthemaindynamicsofthesedimenttransportiscorrectlyreproduced.Themainadvantageofthepresentapproachistosupplyconsistenttimeevolutionsofsedimentconcentrationswithoutmakinguseofanydetailedshearinformation.
简介:Artemisiaordosica是为在西北的中国的沙稳定的优秀修理沙的灌木。沙沙丘稳定,一个极其重要的过程,在不能生活的因素的领先变化,例如土壤,结构和营养素满足。然而,A上的因素的效果。ordosica社区追随者沙稳定遗体不清楚。在这研究,我们使用了正规通讯分析(CCA)检验在A之间的关系。在三个产地的ordosica社区和环境因素:修理半的沙丘(SF),有低范围的生物土壤外壳(F)的固定沙丘,和有在亩的高范围的生物土壤外壳(FC)的固定沙丘我们沙漠。植物的吝啬的高度和范围与沙稳定增加了,当种类差异和丰富开始增加了然后显著地减少了时。关联分析和CCA揭示了那个斜坡,玷污器官的碳,和营养素内容,好土壤粒子的比例,土壤潮湿,和生物土壤外壳的厚度都高度与植被特征被相关。这些环境因素能解释40.42?在三个产地的植被环境关系的%。植物种类的分发是断然与在SF沙丘的土壤潮湿有关。土壤潮湿,土壤营养素,和好粒子的内容主要在F沙丘影响了植物分发。在FC沙丘,植物种类的分发断然并且否定地在深度0-20与生物土壤外壳和土壤潮湿的厚度被相关?厘米分别地。典型大草原种类的优势价值增加了在种类之间的显著地后面的沙沙丘稳定和关系,在CCA分类双性人阴谋的样品证明长期的草能入侵A。FC上的ordosica社区,显示A。ordosica社区有一个趋势与进一步的固定变成典型大草原植被。我们断定重要区别不仅在沙丘固定的三个阶段之中发生在社区特征,而且在在植被和环境因素之间的关系中。那么,降级的沙丘生态系统的恢复应该基于产地条件和生态的需要。
简介:上面的三叠纪的Xujiahe()在四川的形成()盆,西南中国为盆规模沙免职是特殊的。这相对稀罕的沉积现象很好没被解释。这里,我们由讨论沉积框架和概念的模型处理了这个问题。沉积设定的分析暗示盆在免职期间收到了违反。它有多重起源供应和河网络,作为被在包括北方,东方和南方的多重方向的oldlands包围。因此,盆被沿海、广泛地开、浅的湖的免职通常在晚三叠纪的Xujiahe时期期间描绘。这类似于现代著名Poyang()湖。因此,我们与类似物在Xujiahe时期期间调查了框架和四川盆的概念的模型到波伊昂·莱克。结果证明免职的概念的模型能被划分成transgressive和回归的阶段。形成的第一,第三和第五个成员在transgressive舞台,存款被岸和浅湖的泥统治。相反,免职在回归的阶段期间主要具有编织的河隧道沙存款,主要包括形成的第二,第四和第六个成员。扔在的沙因为侧面的移植并且十字的前面的移动,几乎,全部盆编织的河联网。短、快速的违反和相对长的回归的多重引申对盆规模沙免职有益。因此,编织的河的主要隧道和它的extensional区域为烃水库的发展是有利的。这提供实际意义给水库评估和探索。另外,结果也在学习区域认为相对特殊的沉积现象正当并且可以也为在其它地方理解大规模沙免职有含意。