简介：Basedonthetensoranalysisofwater-sedimenttwo-phaseflow,thebasicmodelequationsforclearwaterflowandsediment-ladenflowarededucedinthegeneralcurvecoordinatesfornaturalwatervariable-densityturbulentflow.Fur-thermore,correspondingboundaryconditionsarealsopresentedinconnectionwiththecompositionandmovementofnon-uniformbedmaterial.Thetheoreticalresultsareappliedtothecalculationofthefloatopencaissonintheconstructionperiodandgoodresultsareobtained.

简介：微地形学;小地貌是影响分开，运输，和流量的侵蚀过程的高地区域的一个重要表面特征。然而，很少量的信息都不关于在微地形学和沉积产出的表面之间的关系是可得到的。实验室降雨模拟研究被进行为四不同侵蚀决定易受影响的土壤在微地形学和沉积各在0.75h持续时间和60公里h^-1紧张的一系列6～8暴风雨期间产出的表面的变化。选择的土壤是Grenada的Ap材料sil(GlossicFragiudalfs)，Atwoodsil(TypicPaleudalfs)，和Forestdalesicl(TypicOchraqualfs)，以及C材料，Glauconitic沉积，Rustonsil(TypicPaleudalfs)。土壤床与一个像苗床的表面条件在斜槽被准备。在所有前并且在每暴风雨以后，表面微地形学用激光microreliefmeter被决定。微地形学;小地貌，以吝啬的本地地志的坡度，和流量数据表示了在四土壤之中显示一个很类似的模式。沉积集中的开始快速的增加，它快速到达了最大值然后逐渐地减少了到一个近的常数在暴风雨系列的结束珍视的数据表演。沉积产量仔细由于近经常的流量率跟随了沉积集中趋势。微地形学在第一暴风雨期间，但是然后很快改变了的表面减少了对为大多数在顺序的以后的暴风雨的近似经常的价值更渐渐。在沉积yield-microtopography关系中的三个不同阶段被认出：(1)preponding分阶段执行，(2)增加池溏的沉积产量分阶段执行的一根柱子，并且(3)一根柱子减少池溏的沉积收益阶段。这些阶段在粗糙驱散，小河发展，和土壤表面的土壤侵蚀过程的相对重要性反映变化矩阵稳定。

简介：Thehydraulicandsedimentdepositionproblemsinthewaterintakesystemofapumpinghousewerestudiedbyphysicalmodel.Theexperimentalresultsofdifferentworkingcasesindicatethatthesedimentdepositionsatthegates,stillingbasinandculvertsareveryfewwhenthesystemwasnormallyoperated,butintheforebayofpumpinghouse,especiallyinthepumpinghouseforlivingwater,theamountofsedimentdepositionsometimesisconsiderablylarge.Atthefrontoftheentryofpumpinghouseforlivingwater,installingasetofobliquepipescanpreventthecoarsegrainstoenterit,thedepositionamountwillobviouslydecrease.

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简介：１ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｓｅｒｖｏｉｒｓｅｄｉｍｅｎｔａｔｉｏｎｉｓｒｅｃｏｇｎｉｚｅｄａｓｏｎｅｏｆｔｈｅｍａｉｎｐｒｏｂｌｅｍｓａｆｅｃｔｉｎｇｔｈｅｅｃｏｎｏｍｉｃｓｏｆｍａｎｙｗａｔｅｒｒｅｓｏｕｒｃｅｓｐｒｏｊｅｃｔｓ．Ｍａｎｍａｄ...

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简介：NitrogenandphosphoruscontentsareanalyzedintheoverlyingwatersandporewaterstakenfromtheChangjiangEstuaryandShanghaicoastaltidalflatsinthisstudy.Inaddition,thediffusionfluxesofnitrogenandphosphorusacrossthesediment-waterinterfaceintidalflatsareestimatedaccordingtothenutrientconcentrationgradientsattheinterface.Ithasbeenindicatedthattheconcentrationsofammonium,nitrite,nitrateanddissolvedphosphorusinoverlyingwatersrangefrom0.0082～2.56,0.03～0.58,0.69～5.38and0.035～0.53mg/L,respectively,while0.0025～1.35mg/LforNH4+-N,0.0055～0.20mg/LforNO2--N,0.61～1.14mg/LforNO3--Nand0.11～0.53mg/LforDPinsurfaceporewaters.Thefindingshaverevealedthatammonium,nitrite,nitrateanddissolvedphosphorusdiffusionfluxesacrossthesediment-waterinterfacearebetween-0.024～0.99,-0.39～-0.0019,-3.09～thesourceofphosphorusandanimportantsinkfornitrogeninthewaters.

简介：SurfacesedimentsamplestakenfromtheEastChinaSeaofftheChangjiangestuaryareusedasrawmaterialsforphosphorusreleasingexperiment.Itisfoundthatafterbeingthoroughlymixedwithseawaterforabout10minutes,phosphorusreleasedfromthesedimentsreachesitsmaximumvalue.AdsorptionkineticscanbefittedwithbothElovichequationandtwo-constantrateequation.Thereleasingamountiscloselyrelatedtothecompositionofthesediments.Phosphorusreleasefromsiltyandmuddysedimentishigherthanfromthatdominatedbysandycomposition.Forthedesorptionreaction,iron-phosphorus(Fe-P)isthemostactiveone,withareleasingratiohigherthanotherphosphorusforms,followedbyabsorbed-phosphorus(Ad-P)andorganicboundphosphorus(OP).Allofthemcanbereferredtoasbio-availablephosphorus.Theresultsdemonstratethatphosphorusinsedimentscanbereleasedintoseawaterundersuitablehydrodynamicconditions,andhaveagreatimpactonthenutritionstateandprimaryproductivityofmarinebiosphere.

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简介：Thestructuralpropertiesofwateratdifferenttemperatureshavebeeninestigatedusingaflexiblewatermodelintheisothermal-isobaricensemble.Withdecreasingtemperature,thetetrahedralityofthedistributionofthewatermoleculesaroundthecentralwatermoleculeisenhanced,andthehydrogenbondsbecomemorelinear.Bymeansofaconjugategradientenergyminimization,dynamicalconfigurationsatvarioustemperatureshavebeenmappedontonearbypotential-energyminima,the50°-60°peak(P1)inthedistributionfunctionoftheO-O-Oangleofatrimerbecomesfarsmaller.HoweverthereappearstobeasmallbutobservabletemperaturedependenceofP1,i.e.thehigherthetemperature,thehighertheP1intensity.

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简介：Thepaperprovidesacomprehensivetestingoftheapplicabilityof13sedimenttransportformulasunderdifferentflowandsedimentconditions.Thedimensionlessparametersusedfortestingthereliabilityandsensitivityofformulasaredimensionlessparticlediameter,relativedepth,Froudenumber,relativeshearvelocity,dimensionlessunitstreampower,andsedimentconcentration.Atotalof3,391setsoflaboratoryandriverdataareusedinthetests.Engineersmayfindthetestresultsusefultotheirselectionofformulasunderdifferentflowandsedimentconditions.

简介：Thispaperprovidesastep-by-stepderivationofthesedimenttransportfunctionsbyEngelundandHansen(1967)andbyAckersandWhite(1973).ThetheoreticalderivationsdemonstratethatthesetwofunctionsarecloselyrelatedtoBagnold's(1966)streampowerandefficiencyconcepts.

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