简介:Gullysystemsandwatershedsaregeomorphicunitswithclearboundariesthatarerelativelyindependentofbasinlandscapesandplayanimportantroleinnaturalgeography.InordertoexplorethemorphologicalcharacteristicsofgullysystemsandwatershedsintheDry-HotValley[SouthWest(SW)China],gulliesareinterpretedfromonlineGoogleimageswithhighresolutionandwatershedsareextractedfromdigitalelevationmodelatascaleof1:50,000.Theresultsshowthat:(1)Thereare17,382gullies(withatotalareaof1141.66km^2)and42watershedsinthestudyarea.(2)Theaveragegullydensityofthestudyarea(D)is4.29km/km^2,gullyfrequency(F)is14.39gullies/km^2,thebranchingratio(B)is5.13,thelengthratio(L)is3.12,andthecoefficientofthemainandtributarygullies(M)is0,06.Thedegreeofgullyerosionisstrongtoextremelystrong,themaindevelopmentintensityofgullyerosionrangesfromintensetomoderate,andthetypeofgullysystemistributary.(3)Thewatershedareas(A)arebetween0.39and96.43km^2,thereliefratio(R)isfrom0.10to0.19,thecircularityratio(C)isfrom0.30to0.83,thetextureratio(T)isfrom0.82to39.35,andthedominantgeomorphologicaltexturetypeisfine.(4)ThereisaquantitativerelationshipbetweenFandD:F=0.624D2(R=0.84)andTiscloselyrelatedtoD,F,M(R2>0.7).A,RandCarerelatedtoM(R2>0.5).Thedevelopmentofgullysystemsistheresultofcouplingeffectsbetweenmultiplefactors.Inthisarea,thedegreeoferosionandtheconditionofthemainandtributarygulliescanbecontrolledbythedegreeoftopographicbreakageinthewatershed,whichprovidessometheoreticalbasisfortheevaluationofgullyerosionbythelatter.Inaddition,thescale,relief,andshapehaveasignificantimpactonthelocationsofthemainandtributarygullies.Fortributarygullies,attentionshouldbepaidtotheinterceptionandcontrolofrunoffandsedimentinthesmallconfluencebranchesinordertopreventgullyexpansionandheadadvance.Thesefeaturescaninformthedevelopmentoftargetedmea
简介:摘要:Limahe侵入是在Panxi区域招待Cu-Ni硫化物沉积物的典型岩石。主要元素,踪迹元素和Sr-Nd同位素的geochemical数据第一并且全身地在这研究被报导。改正年龄(87Sr/86Sr),并且Nd(t)同位素值,从0.687062~0.709298,从0.6~4.13分别地,部分重叠Emeishan暗岩和OIB的领域,并且他们通常在上面的外壳和OIB之间躺着。在Limahe侵入和Emeishan大火的省的辉石之间的类似的模式暗示基因关系到Emeishan暗岩。他们的更低的Nb/U(<30),更高(La/Nb)下午并且(Th/Ta)下午比率珍视(>1)显示上面的外壳材料的污染。在MgO和主要氧化物之间的关联在深层的房间反映橄榄石,clinopyroxene和次要的斜长石的部分结晶化。由上面的外壳的污染的因此增加的SiO2和降低的FeO可以触发不能混合的硫化物融化,它然后沿着结构的破裂流动了并且侵入了进gabbrodiorite,导致Cu-Ni硫化物orebody的形成。
简介:摘 要:针对时速160公里鼓形车体动力集中动车组轴箱体内壁出现水珠导致轴承锈蚀问题,介绍了轴箱体密封原理,分析了轴箱体出现水珠的可能原因和影响因素,提出了行之有效的预防措施。
简介:“等边三角形内任意一点到三边的距离之积等于三角形的高。”这就是著名的维维定尼定理。维维安尼(Viviani,1622-1703)是意大利物理学家、数学家,是著名物理学家伽利略的弟子。该定理证法很多,现介绍两种简捷的证法如下: