Results 21 to 30 of about 2,362 (160)
为比较饱和紫色土坡面片流与细沟流水力学特征并明确其临界水力学特性,进行5个坡度(2°,5°,10°,15°,20°)和3个雨强(30,60,90 mm/h)组合 条件下的室内人工模拟降雨试验,在测得坡面片流、细沟流及其转变的临界流速的基础上,计算得到片流、细沟流及其转变的临界水力学参数,包括水深、雷诺数、弗劳德数和达西阻力系数。结果表明:在不同侵蚀阶段,片流流速为0.064~0.151 m/s,细沟流流速为0.175~0.350 m/s,雨强和坡度在不同侵蚀阶段对流速和水深的影响程度存在差异 ...
谭文浩 +5 more
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坡度和地表径流量是影响坡面土壤侵蚀的两个重要参数。由于细沟间侵蚀和细沟侵蚀的力学机理不同,在土壤侵蚀研究中需要区别对待。一般地,细沟间侵蚀量占坡面总侵蚀量的比例很小,因此,细沟侵蚀在坡面侵蚀中非常重要,而坡度和径流量对细沟侵蚀的影响十分显著。目前,大多数学者认为对于同一坡度,剥蚀率和含沙量均会随着径流量的增长而增长;然而坡度和径流量对细沟的综合影响规律目前还认识不十分清楚,有待于进一步探索。为了深入认识细沟侵蚀的过程及特性,本文利用一维细沟侵蚀模型进行坡面侵蚀的数值实验,细致探讨了细沟侵蚀的基本特性 ...
刘青泉, 安翼, 李妍敏
core
Plant nutrient‐acquisition strategies contribute to species replacement during primary succession
Pioneer species Hippophae acquires phosphorus and nitrogen mainly by ‘mining’ and N2‐fixing strategies and thus dominates in the beginning of primary succession. As soil nutrient availability increases with the mobilization of apatite‐P and input of N‐rich plant residues, Hippophae' strategies become less efficient than Populus's scavenging strategies.
Xiao‐Long Li +12 more
wiley +1 more source
为深入探究辽西低山丘陵区坡耕地土壤侵蚀机理,以该区的典型土壤类型褐土和棕壤为研究对象,采用室内人工降雨模拟试验,研究3种坡度(5°,10°,15°)和3种降雨强度(40,60,80 mm/h)下细沟侵蚀发生的阶段性水沙变化过程。结果表明:褐土与棕壤坡面侵蚀过程可划分为3个阶段,即细沟侵蚀之前阶段、跌坎发育阶段和细沟侵蚀快速发育阶段;细沟侵蚀之前的面蚀阶段,同一坡度条件下,褐土与棕壤随雨强的增加,坡面流速呈增大趋势,而在同一雨强条件下,坡度对流速的影响并无明显规律;细沟侵蚀阶段,当坡度一定条件下 ...
吕刚 +6 more
doaj
为探究花岗岩红壤细沟形态特殊变化的原因,解释土体构型影响细沟形态发育的机理。设计单一红土层(H)、单一砂土层(S)、上红下砂层状土层(HS)3种土体构型、不同径流量(低径流量3 L/min、高径流量6 L/min)和不同坡度(中坡20°、陡坡40°)的室内模拟细沟冲刷试验。结果表明:H处理下,细沟形态更多向"V"形和"U"形发育;S处理下,细沟沟道发育过程中短暂形成上窄下宽的深宽梯形断面后,完全崩塌;HS处理下,细沟形态能发育为梯形断面,且能继续扩大发育。与H和S相比,HS陡坡(40 ...
刘子轩 +4 more
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Design and Implementation of Party Construction Management Information System for a University [PDF]
随着信息化技术以及互联网的蓬勃发展,网络信息化已成为了社会发展的潮流以及趋势。为了切实提高基础党务的工作效率,加强与基层党员以及群众的交流,增强党务工作的透明度,方便基层党务人员的管理。因此,迫切需要建立一套党建管理系统。 本文用领域驱动设计的思想结合某高校党建工作的需求完成党建管理系统建设,主要工作包括: 1.利用B/S架构,以Java作为开发语言,将传统党务实施困难的项目与互联网、移动网结合,以系统管理的方式管理使得繁琐的日常管理工作得到简化整合,优化党务工作流程,提高党务办理效率和质量。 2 ...
符慧君
core
Defining, collecting, and sharing perishable disaster data
Researchers across disciplines have long sought to collect ‘perishable data’ in the context of disasters. Yet, this data type is neither consistently defined nor discussed in specific detail in the literature. To address this gap, this paper defines perishable data and provides guidance on ways to improve both how it is collected and shared.
Rachel M. Adams +2 more
wiley +1 more source
Response of Runoff and Sediment Yield from Maize Slope Farmland in Karst Areas to Slope Gradient [PDF]
[Objective] To elucidate the responses of surface runoff, subsurface runoff, and underground runoff hydrological pathways to slope in maize sloping farmland in Karst regions.
DAI Quanhou +4 more
core +1 more source
Objective: To establish a good communicational bridge among patients, doctors and nurses, and promote quality of holistic nursing through collaborative ward rounds, as well as hoping to further develop the collaborative ward rounds of doctors, nurses ...
Xia, Wen-lan, Zhou, Wei-qi
core +2 more sources
为探究高寒土坡面细沟侵蚀过程机理,建立科学的坡面细沟输沙能力因子模型,服务高寒坡面水土流失治理工作,以藏东南高寒土壤为研究对象,采用室内径流放水冲刷试验,探讨不同流量和坡度条件下细沟水流输沙能力特征。结果表明:(1)高寒土坡面细沟水流输沙能力的临界坡长随输沙能力的增加而变短,范围为3.27~8.31 m;坡度在15°~25°时,临界坡长大约稳定在5.0 m;(2)不同坡度下,高寒土细沟水流输沙能力与流量表现为明显的线性正相关关系(Tc=Aq);小坡度的输沙能力受流量的影响程度大于大坡度;(3 ...
喻武 +5 more
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