Results 11 to 20 of about 4,983 (138)

黄河中游典型流域近60年水沙变化趋势及影响因素

open access: yesShuitu Baochi Xuebao, 2023
为分析黄河水沙成因并预测未来水沙情势,选取黄河中游多沙粗沙区昕水河和朱家川2条流域为研究对象,依据水文站及雨量站1956—2018年降雨和径流泥沙实测数据,采用Mann-Kendall趋势及突变检验、累积距平法和Morlet连续小波分析等方法探讨流域水沙变化趋势,并利用双累积曲线法对水沙变化进行归因分析,量化气候变化及人类活动对水沙变化的相对贡献。结果表明:1956—2018年,昕水河和朱家川小流域年均径流量分别为11.9×107,1.7×107 m3,年均输沙量分别为12.3×106,9.8×106 ...
曲绅豪, 周文婷, 张翔, 佘冬立
doaj  

不同时间尺度濂水流域水沙变化及其驱动因素分析

open access: yesShuitu Baochi Xuebao, 2023
为深入分析流域水沙变化特征及其驱动因素,揭示水沙变化机理机制。以赣南濂水流域为研究区,基于1965—2020年的水文气象数据和土地利用数据,在年尺度和场次暴雨尺度,利用Mann-Kendall检验法、累积距平法、水沙关系曲线、经验统计分析法等,分析水沙变化特征,建立不同时期水沙关系,并定量评估降雨变化和人类活动对水沙变化的贡献率。结果显示:(1)在年尺度,流域径流深、输沙量分别呈非显著下降和极显著上升趋势,突变年份分别为1998年和1995年。(2)与基准期相比 ...
盛菲, 刘士余, 余敏琪, 戴余典
doaj  

Patient–provider perspectives on self‐management support and patient empowerment in chronic care: A mixed‐methods study in a rural sub‐Saharan setting 病患自我管理互助角度和慢性病人护理授权:撒哈拉以南农村地区进行的混合方法研究

open access: yesJournal of Advanced Nursing, Volume 75, Issue 11, Page 2980-2994, November 2019., 2019
Abstract Aim To explore how provision of self‐management support to chronically‐ill patients in resource‐limited settings contributes to patient empowerment in chronic care. Design Concurrent descriptive mixed methods research. Methods A survey of 140 patients with chronic conditions administered at four time‐points in 12 months.
Vibian Angwenyi   +4 more
wiley   +1 more source

Attribution analysis of water-sediment variation under the influence of climate change and human activities in the Kuye River Basin [PDF]

open access: yes
The attribution of the evolution of water and sediment in a river basin is an important theoretical issue in hydrogeology. To understand the change patterns of water and sediment in the Kuye River Basin and provide scientific basis for water resources ...
Jiankang ZHANG   +2 more
core   +1 more source

黄河(内蒙古段)水沙运动过程特征及演变趋势

open access: yesShuitu Baochi Xuebao, 2020
近年来受上游水库、河道控导工程和气候变化等因素影响,黄河(内蒙古段)呈现水沙异源、水少沙多的特性,导致河道萎缩和泥沙淤积严重,河道形态演变剧烈,严重威胁夏汛及凌汛行洪安全,也对河道及两岸的生态环境造成严重影响。选取黄河(内蒙古段)干流入境石嘴山水文站和出境头道拐水文站水沙过程为研究对象,分别采用频谱分析法、R/S极差分析法和Markov链分析法系统研究2009-2016年两站逐月水沙运动变化的时序、运动状态和演变特征,讨论影响水沙运动变化过程的关键因素。结果表明 ...
李超   +4 more
doaj  

毛乌素沙地圪丑沟小流域沙柳水分利用来源研究

open access: yesShuitu Baochi Xuebao, 2021
为探究毛乌素沙地典型治沙植物根系吸水来源及其影响因素,通过测定毛乌素沙地圪丑沟小流域沙柳(Salix psammophila)(18~20年)木质部水及其各种潜在水源(降水、土壤水和地下水)的氢氧同位素组成(δD和δ18O),利用多元线性混合模型(IsoSource)研究沙柳水分来源的季节变化特征及其影响因素。结果表明,监测期间(6-11月)沙柳木质部水、降水、土壤水和地下水的δD值变化范围分别为-82.41‰~-52.91‰,-144.81‰~-6.60‰,-96.94‰~-42.65‰和-86.42‰
李荣磊   +4 more
doaj  

Devouring the Invaders: The Racial‐Ecological Politics of the Chinese Crayfish Trade in Kenya

open access: yesAmerican Anthropologist, Volume 128, Issue 1, Page 183-194, March 2026.
ABSTRACT This article examines entanglements of ecology, race, and foodways at Lake Naivasha in Kenya. Nonnative Louisiana red swamp crayfish (Procambarus clarkii), first introduced to Kenya in the 1960s, were once viewed as invasive but are now sought after as a delicacy among Kenya's Chinese community.
Amanda Kaminsky
wiley   +1 more source

绿洲-荒漠交错带不同沙丘土壤水分时空动态变化规律

open access: yesShuitu Baochi Xuebao, 2007
绿洲-漠交错带是植被恢复的一个重要区域,而植被恢复的关键又是了解沙丘土壤水分的变化规律。从2003年10月到2004年10月,对甘肃省张掖绿洲-荒漠交错带沙丘土壤水分进行了连续观测,并研究了生态垫在沙漠治理中的应用。结果表明:土壤水分时空动态变化主要受降雨、植被以及地表覆盖等因素的影响,沙丘土壤水分月变化滞后于降水变化。沙丘剖面土壤水分变异系数随土层深度的增加而减小,铺设生态垫减小了沙丘土壤水分的空间变异(CV=4.43%),流动沙丘0~40cm的含水量(0.19%~1.27%)低于固定沙丘(1.61%~
李禄军   +4 more
doaj   +2 more sources

复合侵蚀作用下砒砂岩坡面侵蚀泥沙颗粒特征

open access: yesShuitu Baochi Xuebao, 2021
明晰砒砂岩坡面侵蚀泥沙颗粒输移特征是研究黄河泥沙淤积问题的关键。采用水力、风力、冻融复合侵蚀实体模拟技术,研究在35°坡度和110 mm/h雨强条件下单一水蚀、冻融+水蚀、冻融+风蚀+水蚀3组不同侵蚀动力复合作用下,砒砂岩坡面侵蚀泥沙颗粒变化特征。结果表明:砒砂岩坡面在单一水蚀作用下以整体侵蚀为主,侵蚀泥沙颗粒变化稳定;冻融+水蚀作用下粗颗粒产出明显,冻融作用对粗颗粒的影响凸显;冻融+风蚀+水蚀作用下坡面稳定性最差,侵蚀泥沙颗粒变化最剧烈。复合侵蚀作用下坡面侵蚀过程以搬运粒径较大的泥沙颗粒为主 ...
高玄娜   +4 more
doaj  

Effects of Vegetation Restoration on Soil Infiltration and Runoff in the Gully Regions on the Loess Plateau [PDF]

open access: yes
[Objective] To study the effects of vegetation restoration on rainfall infiltration and runoff is of great theoretical and practical value for rational utilization of watershed water resources and ecological construction.
BAI Yungang   +4 more
core   +1 more source

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