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:摘要近些年来,国家对于环保的要求不断提高,各行各业随之也更加注重可持续发展以及绿色能源的使用。建筑行业中也在多个方面践行了这一原则,sw现浇混凝土内置保温体系就是其中一个比较典型的方面。相较于传统粘贴式外墙保温方式,sw现浇混凝土内置保温不管是在绿色环保方面,还是具体实际运用方面,都具有更大的优势。
简介:摘要在向量学习中,经常会涉及到三角形的几心——重心、外心、垂心、内心等。尤其以三角形的内心最难,因为对三角形内心的处理手段较为单一,不易计算。本文探究了一个定理的推广——“奔驰定理”
简介:目的研究结直肠癌细胞炎症模型中基因表达的变化以及所涉及的信号通路。方法利用脂多糖(LPS)刺激SW480细胞1、3、6小时后提取RNA构建测序文库进行转录组测序,对表达有变化的基因归类,并进行京都基因与基因组百科全书(Kyotoencyclopediaofgenesandgenomes,KEGG)分析,对分析结果进行实时荧光定量PCR验证。结果发现LPS刺激SW480细胞1、3、6小时后,3个时间点表达均有显著变化的基因有250个。对这些差异表达的基因进行了KEGG信号通路富集分析发现利用脂多糖刺激构建的炎症模型里,TNF-α激活和NF-κB信号通路活化最显著。利用癌症基因组图谱(TCGA)数据库进一步对表达持续上调或下调的基因进行分析发现,部分基因在结肠癌标本中的表达趋势与LPS刺激结肠癌细胞引起的表达变化趋势一致。结论在利用脂多糖刺激构建的结肠癌细胞炎症模型中,炎症过程中的基因表达变化可能与结肠癌的发生发展密切相关。