In this paper,according to the rule of unbalanced sediment transport and the analysis of field data,different water diversion schemes were theoretically studied,including the erosion and sedimentation trend as well as...In this paper,according to the rule of unbalanced sediment transport and the analysis of field data,different water diversion schemes were theoretically studied,including the erosion and sedimentation trend as well as their impacts on the environment of the middle and lower reaches of the Hanjiang River.The results showed that the 95×108m 3 water diversion scheme will cause less erosion and water level decrease than the 15×108m 3 water diversion scheme.Using a water diversion scheme of 95×108m 3,the decrease of water quantity can impact the river hydrodynamic regime substantially and the environments of the middle and lower reaches of the Hanjiang River will be greatly affected.It is therefore necessary to develop new water resources or build projects to meet the need of the environment and the needs for navigation.展开更多
Projection Pursuit (PP) model is a technique of falling high dimension. Real coding based on Accelerating Genetic Algorithm (RAGA) is a method of optimum. Through combining the PP model and RAGA, the paper applies the...Projection Pursuit (PP) model is a technique of falling high dimension. Real coding based on Accelerating Genetic Algorithm (RAGA) is a method of optimum. Through combining the PP model and RAGA, the paper applies the model in the water environment quality evaluation. The writer takes the water quality evaluated indexes of each sample as projection direction and turns high dimension data into low dimension projection value. Thus, the writer achieves on evaluating the grade of water samples and its optimum order. Based on this, the writer overcomes the jamming of weights calculated on fuzzy synthesize judge and gray system valuation. The paper can provide a new thought for water environment quality evaluation and other falling high dimension and optimum issue.展开更多
1. PREFACE Lingdingyang is a trumpet estuary. It accepts the runoff of the Dongjiang River, the Beijiang River, the Zhengjiang River and the Liusihe River. It also accepts a part of the runoff of the Xijiang River. It...1. PREFACE Lingdingyang is a trumpet estuary. It accepts the runoff of the Dongjiang River, the Beijiang River, the Zhengjiang River and the Liusihe River. It also accepts a part of the runoff of the Xijiang River. Its mean year runoff is 1.742×10" M^3. In resent ten years, industry and agriculture are developing rapidly in Guangzhou City, Dongguan City, Zhongshan City, Shunde County, Panyu County. Lingdingyang’s pollution is increesing. Water quality of lingdingyang is steadily deteriorated. In order to investigate the situation of water environment of Lingdingyang, we study its static environmental capacity of nitrogen and phosphorus. LANDSAT imageries are used in the study. The concentrations of nitrogen and phosphorous is detected by convention method.展开更多
Erosion and transport of soil has worldwide implications for agriculture, landscape stability, climate, natural hazards, and clean, renewable resources of water and air. Assured access to clean water and a healthy and...Erosion and transport of soil has worldwide implications for agriculture, landscape stability, climate, natural hazards, and clean, renewable resources of water and air. Assured access to clean water and a healthy and safe environment requires an ethic of conservation and protection. The minimum scale in which these principles apply successfully is basin wide. These are the fundamental concerns of the Sino-US Centers for Soil and Water Conservation and Environmental Protection.展开更多
The East African Rift extending across Djibouti, Ethiopia and Kenya is characterized by low level of economic development,high level of poverty,increasing population,scarce natural resources(land,water, and environmen...The East African Rift extending across Djibouti, Ethiopia and Kenya is characterized by low level of economic development,high level of poverty,increasing population,scarce natural resources(land,water, and environment),complex and rich ecosystems, increasing desertification and degrading biodiversity, underdeveloped regional trade and market,water resources mainly stored in groundwater and展开更多
Fuzzy comprehensive evaluation method was used to develop a standard model to analyze and evaluate nearness degree of water environment quality at breeding area of Shuidong Bay in China.Results showed that certain env...Fuzzy comprehensive evaluation method was used to develop a standard model to analyze and evaluate nearness degree of water environment quality at breeding area of Shuidong Bay in China.Results showed that certain environment contamination factors in some areas seriously exceeded the standard value and led to the whole water quality at the third class level.The measurements should be taken to promote the sustainable development of breeding area in Shuidong Bay.展开更多
本文采用文献计量学方法,利用CiteSpace和VOSviewer软件对1990—2024年Web of Science(WoS)和中国知网(CNKI)数据库中有关土壤锑(Sb)污染研究的文献进行系统分析。结果表明:相关内容在近5年(2020—2024年)的发文量显著增长,占35年总发...本文采用文献计量学方法,利用CiteSpace和VOSviewer软件对1990—2024年Web of Science(WoS)和中国知网(CNKI)数据库中有关土壤锑(Sb)污染研究的文献进行系统分析。结果表明:相关内容在近5年(2020—2024年)的发文量显著增长,占35年总发文量的1/3。英文文献发展历程可分为3个阶段:萌芽期(1990—2004年)主要聚焦Sb分析测定方法的建立与污染源识别,通过实际样品分析验证技术的可靠性;发展期(2005—2014年)系统探究Sb在土-水界面的吸附/解吸过程、氧化/还原耦合机制,以及进行生态毒性与健康风险评估;交叉融合期(2015—2024年)则深度融合微生物学、材料科学和大数据技术,围绕修复材料开发、微生物转化过程及健康影响开展多维度研究。中文文献研究形成四大热点:“Sb分析研究技术”“土壤中Sb的固定”“矿区污染及生态风险评估”和“Sb修复与健康风险评估”,表现出研究从基础方法向污染机理、风险评价及修复技术的系统性推进。未来需深入微观机制、强化复合污染研究、开发高效修复技术,并加强标准完善与国际合作,以应对土壤Sb污染的复杂挑战。展开更多
文摘In this paper,according to the rule of unbalanced sediment transport and the analysis of field data,different water diversion schemes were theoretically studied,including the erosion and sedimentation trend as well as their impacts on the environment of the middle and lower reaches of the Hanjiang River.The results showed that the 95×108m 3 water diversion scheme will cause less erosion and water level decrease than the 15×108m 3 water diversion scheme.Using a water diversion scheme of 95×108m 3,the decrease of water quantity can impact the river hydrodynamic regime substantially and the environments of the middle and lower reaches of the Hanjiang River will be greatly affected.It is therefore necessary to develop new water resources or build projects to meet the need of the environment and the needs for navigation.
文摘Projection Pursuit (PP) model is a technique of falling high dimension. Real coding based on Accelerating Genetic Algorithm (RAGA) is a method of optimum. Through combining the PP model and RAGA, the paper applies the model in the water environment quality evaluation. The writer takes the water quality evaluated indexes of each sample as projection direction and turns high dimension data into low dimension projection value. Thus, the writer achieves on evaluating the grade of water samples and its optimum order. Based on this, the writer overcomes the jamming of weights calculated on fuzzy synthesize judge and gray system valuation. The paper can provide a new thought for water environment quality evaluation and other falling high dimension and optimum issue.
文摘1. PREFACE Lingdingyang is a trumpet estuary. It accepts the runoff of the Dongjiang River, the Beijiang River, the Zhengjiang River and the Liusihe River. It also accepts a part of the runoff of the Xijiang River. Its mean year runoff is 1.742×10" M^3. In resent ten years, industry and agriculture are developing rapidly in Guangzhou City, Dongguan City, Zhongshan City, Shunde County, Panyu County. Lingdingyang’s pollution is increesing. Water quality of lingdingyang is steadily deteriorated. In order to investigate the situation of water environment of Lingdingyang, we study its static environmental capacity of nitrogen and phosphorus. LANDSAT imageries are used in the study. The concentrations of nitrogen and phosphorous is detected by convention method.
文摘Erosion and transport of soil has worldwide implications for agriculture, landscape stability, climate, natural hazards, and clean, renewable resources of water and air. Assured access to clean water and a healthy and safe environment requires an ethic of conservation and protection. The minimum scale in which these principles apply successfully is basin wide. These are the fundamental concerns of the Sino-US Centers for Soil and Water Conservation and Environmental Protection.
文摘The East African Rift extending across Djibouti, Ethiopia and Kenya is characterized by low level of economic development,high level of poverty,increasing population,scarce natural resources(land,water, and environment),complex and rich ecosystems, increasing desertification and degrading biodiversity, underdeveloped regional trade and market,water resources mainly stored in groundwater and
基金Supported by China Postdoctoral Science Foundation(20090460873)
文摘Fuzzy comprehensive evaluation method was used to develop a standard model to analyze and evaluate nearness degree of water environment quality at breeding area of Shuidong Bay in China.Results showed that certain environment contamination factors in some areas seriously exceeded the standard value and led to the whole water quality at the third class level.The measurements should be taken to promote the sustainable development of breeding area in Shuidong Bay.
文摘本文采用文献计量学方法,利用CiteSpace和VOSviewer软件对1990—2024年Web of Science(WoS)和中国知网(CNKI)数据库中有关土壤锑(Sb)污染研究的文献进行系统分析。结果表明:相关内容在近5年(2020—2024年)的发文量显著增长,占35年总发文量的1/3。英文文献发展历程可分为3个阶段:萌芽期(1990—2004年)主要聚焦Sb分析测定方法的建立与污染源识别,通过实际样品分析验证技术的可靠性;发展期(2005—2014年)系统探究Sb在土-水界面的吸附/解吸过程、氧化/还原耦合机制,以及进行生态毒性与健康风险评估;交叉融合期(2015—2024年)则深度融合微生物学、材料科学和大数据技术,围绕修复材料开发、微生物转化过程及健康影响开展多维度研究。中文文献研究形成四大热点:“Sb分析研究技术”“土壤中Sb的固定”“矿区污染及生态风险评估”和“Sb修复与健康风险评估”,表现出研究从基础方法向污染机理、风险评价及修复技术的系统性推进。未来需深入微观机制、强化复合污染研究、开发高效修复技术,并加强标准完善与国际合作,以应对土壤Sb污染的复杂挑战。
