Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to...Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.展开更多
2014年美国教育研究协会(American Education Research Association,简称AERA)年会在美国费城召开,"促进实践与政策创新的教育研究力量"是本届AERA年会的主题。研究本届年会上教育科学领域共同关注的两个主题,可以全面了解本...2014年美国教育研究协会(American Education Research Association,简称AERA)年会在美国费城召开,"促进实践与政策创新的教育研究力量"是本届AERA年会的主题。研究本届年会上教育科学领域共同关注的两个主题,可以全面了解本届AERA年会上前沿的教育研究动态。教育技术领域的研究者可以从教育技术的视角,围绕"学习技术"这一核心要点,从学习过程和学习资源的设计、开发、运用与管理以及评价四个方面,对年会上涉及的教育技术相关内容进行全面解读,为教育技术自身专业的发展及其与其他学科的交叉发展提供一定的借鉴和指导方向。展开更多
2017年4月27日-5月1日,美国教育研究协会(American Educational Research Association,AERA)年会在圣安东尼奥市召开,年会的主题是"从知识到行动:实现教育机会均等的承诺"。大会研究专题广泛而新颖,其中就教育技术领域而言,...2017年4月27日-5月1日,美国教育研究协会(American Educational Research Association,AERA)年会在圣安东尼奥市召开,年会的主题是"从知识到行动:实现教育机会均等的承诺"。大会研究专题广泛而新颖,其中就教育技术领域而言,可以从教与学、技术、测评三个视角对年会上涉及的相关内容进行全面解读,并从理论研究、技术发展和研究方法三个方面对当前研究热点及趋势进行概述与分析,呈现教育技术领域的最新动态与热点研究,旨在为该领域自身发展与跨领域合作提供一定借鉴和指导。展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.52221003,42277044)。
文摘Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.
文摘2014年美国教育研究协会(American Education Research Association,简称AERA)年会在美国费城召开,"促进实践与政策创新的教育研究力量"是本届AERA年会的主题。研究本届年会上教育科学领域共同关注的两个主题,可以全面了解本届AERA年会上前沿的教育研究动态。教育技术领域的研究者可以从教育技术的视角,围绕"学习技术"这一核心要点,从学习过程和学习资源的设计、开发、运用与管理以及评价四个方面,对年会上涉及的教育技术相关内容进行全面解读,为教育技术自身专业的发展及其与其他学科的交叉发展提供一定的借鉴和指导方向。
文摘2017年4月27日-5月1日,美国教育研究协会(American Educational Research Association,AERA)年会在圣安东尼奥市召开,年会的主题是"从知识到行动:实现教育机会均等的承诺"。大会研究专题广泛而新颖,其中就教育技术领域而言,可以从教与学、技术、测评三个视角对年会上涉及的相关内容进行全面解读,并从理论研究、技术发展和研究方法三个方面对当前研究热点及趋势进行概述与分析,呈现教育技术领域的最新动态与热点研究,旨在为该领域自身发展与跨领域合作提供一定借鉴和指导。
