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简介：AsimplecyclicelastoplasticconstitutivemodelforsandisproposedbasedontheUHmodelforoverconsolidatedclay.Theproposedmodelhasthefollowingfeatures.First,inordertodescribethestress-inducedanisotropyinsand,arotationalhardeningruleisintroducedfortheevolutionoftheyieldsurfaceaxiswithdevelopmentofplasticdeviatoricstrainintheprincipalstressspace.Second,therelationshipbetweentherotationalaxisandstress-inducedanisotropyismodeledbyintroducingtheslopeofrotationalaxisintotheyieldfunction.Theflatnessoftheyieldsurfacecanbedeterminedbytheslopeofrotationalaxis.Finally,arevisedunifiedhardeningparameterisproposedtoincorporatethestress-inducedanisotropy.Themodelcapabilityindescribingthecyclicresponseofsandisverifiedbycomparingthesimulationswithavailabletestresults.

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简介：Whippedup(激起)bystrongwinds,athickstormofchoking(令人窒息的)sandanddustturnedBeijing'sskiesfromgreytoyellowtoorangelastWednesday.

简介：Sandjetinnon-Newtonianviscoplasticfluidisassociatedwithanumberofindustrialandengineeringapplications,includingsandcappingforthereclamationofoilsandstailingspondsandsedimentdepositionintosoftmud.Inthisstudy,severalexperimentswerecarriedoutbydepositingcircularsandjetsverticallyintoviscoplasticfluids,knownasLaponitegel.Thedeformationregimesofsandjetsinthegelwereinvestigated.Theyield-gravityparameterofthedeformedsanddropinthegelwascomputed.

简介：Theprobabilitydistributionsofsandparticles'lift-offandincidentvelocitiesinawind-blownsandfluxplayveryimportantrolesinthesimulationofthewind-blownsandmovement.Inthispaper,theverticalandthehorizontalspeedsofsandparticleslocatedat1.0mmaboveasand-bedinawind-blownsandfluxareobservedwiththeaidofPhaseDopplerAnemometry(PDA)inawindtunnel.Basedontheexperimentaldata,theprobabilitydistributionsofnotonlytheverticallift-offspeedbutalsothelift-offvelocityaswellasitshorizontalcomponentandtheincidentvelocityaswellasitsverticalandhorizontalcomponentscanbeobtainedbytheequaldistancehistogrammethod.Itisfound,accordingtotheresultsoftheχ2-testfortheseprobabilitydistributions,thattheprobabilitydensityfunctions(pdf's)ofthesandparticles'lift-offandincidentvelocitiesaswellastheirverticalcomponentsaredescribedbytheGammadensityfunctionwithdifferentpeakvaluesandshapesandthedownwindincidentandlift-offhorizontalspeeds,respectively,canbedescribedbythelognormalandtheGammadensityfunctions.Thesepdf'sdependonnotonlythesandparticlediameterbutalsothewindspeed.

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简介：Ｏｎｔｈｅｂａｓｉｓｏｆｐｒｅｖｉｏｕｓｒｅｓｅａｒｃｈａｎｄｐｒａｃｔｉｃｅ，ａｎｅｗｍｏｄｅｌｓａｎｄＢＺＹｈａｓｂｅｅｎｓｕｃｃｅｓｓｆｕｌｌｙｄｅｖｅｌｏｐｅｄ．Ｅｘｐｅｒｉｍｅｎｔｓｈａｖｅｂｅｅｎｃａｒｒｉｅｄｏｕｔｏｎｉｔｓｐｒｏｐｅｒｔｉｅｓ，ｉｎｃｌｕｄｉｎｇｕｎｉｔｗｅｉｇｈｔ，ｉｎｉｔｉａｔｉｏｎｖｅｌｏｃｉｔｙ，ｓｅｔｔｌｉｎｇｖｅｌｏｃｉｔｙ，ｒｅｐｏｓｅａｎｇｌｅ，ｅｔｃ．ＴｈｅｅｘｐｅｒｉｍｅｎｔｓｓｈｏｗｔｈａｔｔｈｅＢＺＹｍｏｄｅｌｓａｎｄｈａｓｍａｎｙｍｅｒｉｔｓｏｖｅｒｏｔｈｅｒｓ，ｓｕｃｈａｓａｄｊｕｓｔａｂｌｅｕｎｉｔｗｅｉｇｈｔ，ｗｉｄｅｒａｎｇｅｏｆｐａｒｔｉｃｌｅｓｉｚｅ，ｐａｒｔｉｃｌｅｓｈａｐｅｓｉｍｉｌａｒｔｏｎａｔｕｒａｌｓａｎｄａｎｄｓｔａｂｌｅｐｈｙｓｉｃａｌａｎｄｃｈｅｍｉｃａｌｐｒｏｐｅｒｔｉｅｓ．Ｔｈｕｓｉｔｈａｓｈｉｇｈｖａｌｕｅｆｏｒｓｔｕｄｙ，ｄｅｖｅｌｏｐｍｅｎｔａｎｄｅｘｔｅｎｓｉｏｎｆｏｒａｐｐｌｉｃａｔｉｏｎ．Ｓｔｉｌｌｓｏｍｅｏｆｉｔｓｐｒｏｐｅｒｔｉｅｓｎｅｅｄｔｏｂｅｆｕｒｔｈｅｒｓｔｕｄｉｅｄ

简介：Experimentalstudyoninitiationofbivalveshellmotiononahorizontalsandbed,underaunidirectionalflowofwater,ispresented.Experimentswerecarriedoutinaflumewiththreetypesofbivalveshells,namelyCoquinaClam,Cross-barredChioneandPonderousArk,totesttheconditionforinitiationofmotion.Theshapeparametersofbivalveshellsaredefinedappropriately.Experimentswereconductedinaflumewithahorizontalbed,andthecriticalshearstresseswereestimatedusingVanoni'sside-wallcorrection.Thecharacteristicparametersaffectingtheinitiationofshellmotiononahorizontalbedinrough-turbulentregimeidentifiedbasedonthephysicalreasoninganddimensionalanalysisaretheShieldsparameter(nondimensionalcriticalshearstress),nondimensionalcompetentmeanvelocity,nondimensionalsandroughness,nondimensionalflowdepthandshapeparameter.EquationsofShieldsparameterandnondimensionalcompetentmeanvelocityfortheinitialmovementofshellsonahorizontalsandbedwithconvexupwardanddownwardconditionsareobtainedusingexperimentaldata.

简介：包括石灰石，沙的六代表性的父母岩石石英岩，片麻岩，花岗石，暗岩和大理石被选择在可使用性，机制性质，体积稳定性和制造沙水泥的耐久性上在生产的沙的各种各样的岩性学的效果上进行系统的研究。试验性的结果证明制造沙水泥的力量比自然沙的水泥的稍微高。而且，分别地与六不同岩性学石头粉末的相等的数量代替具体混合的15%水泥，数据显示他们能改进水泥可使用性，推迟塑料裂开时间，提高击碎反的等级，并且没在防冻剂和硫酸盐攻击抵抗的性质上有明显的效果，但是减少能力抵抗氯化物离子穿入。而且，在生产的沙和石头粉末的各种各样的岩性学引起的水泥可使用性，机制性质，体积稳定性和耐久性的差别不是重要的，水泥的宏性质上的岩性学变化的影响能最后被忽视。

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简介：中国是一个具有大面积沙漠和荒漠化土地的国家，荒漠化危害极为严重．在长期的防治荒漠化过程中，总结积累了大量的防治荒漠化技术和固沙造林技术，具体包括：（１）荒漠化地区封沙育林育草；（２）绿州防护林体系建立；（３）荒漠绿洲农田防护林体系建设；（４）流动沙丘固沙造林；（５）公、铁路防沙造林；（６）飞播造林种草固沙技术．

简介：Inordertoinvestigatetheinfluenceoftheverticalvibrationloadingontheliquefactionofsaturatedsand,onedimensionalmodelforthesaturatedsandwithaverticalvibrationispresentedbasedonthetwophasecontinuousmediatheory.Thedevelopmentoftheliquefactionandtheliquefactionregionareanalyzed.Itisshownthattheverticalvibrationloadingcouldinduceliquefaction.Therateoftheliquefactionincreaseswiththeincreaseoftheinitiallimitstrainorinitialporosityoramplitudeandfrequencyofloading,andincreaseswiththedecreaseofthepermeabilityorinitialmodulus.Itisshownalsothatthereisaphaselaginthesandcolumn.Whenthesandpermeabilitydistributionisnon-uniform,theporepressureandthestrainwillrisesharplywherethepermeabilityisthesmallest,andfracturemightbeinduced.Withthedevelopmentofliquefaction,thestrengthofthesoilfoundationbecomessmallerandsmaller.Inthelimitingcase,landslidesordebrisflowscouldoccur.

简介：一个沉积地质的模型被建立以便学习隧道沙身体的地震思考特征。合成地震射击集合用声学的波浪方程被模仿然后prestack时间被移植。在想象的数据上，思考特征和即时属性被分析，抑制木头的阻抗倒置被测试。因为波浪领域干扰，试验性的结果证明地震事件毫无疑问不对应于隧道沙身体并且出现的地震模式不代表实际的。波浪干扰形成的地震事件可以在沙身体解释导致错误和陷井。在即时地震属性和沉积的沙之间的相应关系很好没被建立。抑制木头的阻抗倒置改进隧道沙的决定。然而，如果转换分辨率被强迫太高，与起始的模型有关的人工制品可以发生。

简介：Sand-duststormsaretheresultoftheintegratedinfluencesofclimate,geography,societyandhumanfactors.Atheoreticalframeworkisbuilttoexplainthecoherenceofpopulationgrowth,agriculturechangeandenvironmentaldegradation.Onthebasisoftheanalysisofthecausesofthesand-duststormintermsofhumanfactors,adiscussionwillbegiventoshowthatthesefactorsareinternallyconsistentwiththetheoreticalframework.Afterthat,itwilllookatChina'sAgenda21andtrytofindrelevantmeasurestoreducesuchlargesand-duststormshappeninginNorthwestChinaandeventuallymakethisareadevelopsustainably.

简介：WesummarizeinthisoverviewachievementsincurrentresearchfrontiersinAsiansanddustwithemphasisonthemethodforsanddustresearch,thesourcesofsanddustaerosols,emissionofsanddust,mechanismofsanddustweather,chemicaltransformationduringtransport,andinfluencesonclimaticenvironmentandoceans.OurmainresultsshowthatmostofAsiansanddustcomesfromMongolia,theGobiDesert,aridandsemiariddesertareasinnorthwestChina,whichisdividedintoinitialsourcesandenhancedsources.HalfoftheglobalproductionofdustoriginatesfromAsiandustsourceregions.Asiandustweatherissoimmensethatitcancovera5-7-dayjourneyfromthesourcestotheKoreanPeninsula,JapanIslands,andthePacificOceantoevenimpactNorthAmerica.Asiandustweatherplaysanactiveroleinthebiogeochemicalcyclesoftraceelementsinthemid-latitudeNorthernHemisphere.

简介：Theresultsofastudyonthekeytechnologyofusingshellsand,akindofseasand,asbackfillforseareclamationaredescribedbriefly.Laboratorytestsshowthatthephysicalandmechanicalpropertiesofshellsandareasgoodasnormalquartzsand.Basedonthechemicaltestanddurabilitytestofshellsanditcouldbeconcludedthattheinfluenceofcorrosionofshellsandbyacidrainandseawatermightbeignoredintheevaluationofthesafetyanddurabilityoftheengineeringproject.Theresultsoffieldimprovementtestsshowthatthebearingcapacityofshellsandbackfillfoundationismorethan200kPaaftervibroflotationimprovementordynamiccompactionimprovement.Theshellsandisagoodbackfillmaterialforseareclamation.

简介：北华南海架上的沙波浪被认为寡妇床形式同样稳定。为在车站LF13-2和LF13-1之间的海床的工业使用，探索的一个新回合被进行。沙波浪的间距和振幅都系统地与水深度正在改变的最新获得的数据表演。自从2003～2004证明海床当前是活跃的，重复了观察。由于表面沉积的强壮的侵蚀自从Dongsha()高举，Dongsha的架上有几乎不现代的沉积区域。在学习区域的沙材料主要从床沉积形成的侵蚀发源。水深度增长由更健全的数据主要由于侵蚀的重复回响揭示了。底部水流在Dongsha的区域是相当复杂的在水下高原。在地点9MKII，向南方退电流比强壮，向北方在地点AEM-HR充满电流，WNW病房洪水水流比ESE病房稍微强壮退当前。在地点9MKII，最大的底部水流速度是48cm/s，并且22%观察底部水流速度比20cm/s大，它遇见为沙波浪的创造要求的最小的底部水流速度。这篇文章指出今日的海洋学的状况与沙波浪形态学联合很好，并且沙飘动，这是在很大程度上在有进行中的今日的海洋学的底部水流的平衡调节并且活跃。