The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, ...The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, China’s state council released “Water Pollution Prevention and Control Action Plan” in 2015. This policy has become a guideline to promote water sustainability in the long run. Since then, a number of regulatory policies were released to increase the focus on water conservation. Among those actions, water loss control associated with distribution systems is regarded as a key solution to improve water supply efficiency. This paper provided a comprehensive introduction to the framework of water loss control policy in China.展开更多
Loess Plateau is the most serious region of soil and water loss in China and the world. The sediment carried into the Yellow River amounts to 1.6 billion tons every year. This paper reviews the factors and reasons for...Loess Plateau is the most serious region of soil and water loss in China and the world. The sediment carried into the Yellow River amounts to 1.6 billion tons every year. This paper reviews the factors and reasons for erosion in this area, and puts forward a comprehensive controlling policy on the basis of the principles of ecology and practise of Chinese scientists for 40 years. In conformity with the policy, a number of technical measures for controlling soil and water loss are suggested.展开更多
A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller's structure. The complicated model was solved with iteration planning algorithm based on Newton search. T...A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller's structure. The complicated model was solved with iteration planning algorithm based on Newton search. The model is proved logical and credible by comparing calculated results and measured data. Then, the relationship between water flow velocity, inlet water temperature, furnace temperature and roller cross section temperature, outlet water temperature, water temperature rise, cooling water heat absorption was studied. The conclusions and recommendations are mainly as follows: 1) Cooling water temperature rise decreases with the increase of water flow velocity, but it has small relationship with inlet water temperature; 2) In order to get little water scale, inlet water temperature should be controlled below 30 ℃. 3) The cooling water flow velocity should be greater than critical velocity. The critical velocity is 0.07 m/s and water flow velocity should be controlled within 0.4 0.8 m/s. Within this velocity range, water cooling efficiency is high and water temperature rise is little. If cooling water velocity increases again, heat loss will increase, leading to energy wasting.展开更多
The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to d...The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.展开更多
[目的]通过分析十大孔兑水土流失面积、强度及水土流失动态变化,为流域综合治理提供参考依据。[方法]基于全国土壤侵蚀遥感调查结果和全国水土流失动态监测成果,对比分析流域水土流失及其分布、动态变化。[结果]十大孔兑流域植被面积占...[目的]通过分析十大孔兑水土流失面积、强度及水土流失动态变化,为流域综合治理提供参考依据。[方法]基于全国土壤侵蚀遥感调查结果和全国水土流失动态监测成果,对比分析流域水土流失及其分布、动态变化。[结果]十大孔兑流域植被面积占流域面积的63.97%,以中低覆盖和低覆盖为主,分别占植被覆盖面积的48.85%和36.54%。2021年水土流失面积为4374.98 km 2,占流域面积的40.63%;与2020年、1999年和1985年相比,2021年水土流失分别减少46.32,3664.50,4958.03 km 2,水土流失主要分布在草地、林地、耕地和其他土地4个地类上,占水土流失总面积的96.69%。[结论]十大孔兑依然是黄河流域水土流失治理的难点地区,高强度侵蚀减少与年度监测成果未考虑沟道侵蚀有关;该区应坚持以“以沙棘种植为主的植被建设,以淤地坝建设为重点的工程布局,以锁边固沙为前提的治沙方针,大力推进拦沙换水试点工程”的流域综合治理策略。展开更多
文摘The Chinese government has raised great attention on water resources and environment over the past several years. In dealing with the issues of water pollution, water management, and the imbalance of water resources, China’s state council released “Water Pollution Prevention and Control Action Plan” in 2015. This policy has become a guideline to promote water sustainability in the long run. Since then, a number of regulatory policies were released to increase the focus on water conservation. Among those actions, water loss control associated with distribution systems is regarded as a key solution to improve water supply efficiency. This paper provided a comprehensive introduction to the framework of water loss control policy in China.
文摘Loess Plateau is the most serious region of soil and water loss in China and the world. The sediment carried into the Yellow River amounts to 1.6 billion tons every year. This paper reviews the factors and reasons for erosion in this area, and puts forward a comprehensive controlling policy on the basis of the principles of ecology and practise of Chinese scientists for 40 years. In conformity with the policy, a number of technical measures for controlling soil and water loss are suggested.
基金Project(2010CB630800) supported by the National Basic Research Program of China
文摘A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller's structure. The complicated model was solved with iteration planning algorithm based on Newton search. The model is proved logical and credible by comparing calculated results and measured data. Then, the relationship between water flow velocity, inlet water temperature, furnace temperature and roller cross section temperature, outlet water temperature, water temperature rise, cooling water heat absorption was studied. The conclusions and recommendations are mainly as follows: 1) Cooling water temperature rise decreases with the increase of water flow velocity, but it has small relationship with inlet water temperature; 2) In order to get little water scale, inlet water temperature should be controlled below 30 ℃. 3) The cooling water flow velocity should be greater than critical velocity. The critical velocity is 0.07 m/s and water flow velocity should be controlled within 0.4 0.8 m/s. Within this velocity range, water cooling efficiency is high and water temperature rise is little. If cooling water velocity increases again, heat loss will increase, leading to energy wasting.
基金Supported by the National Natural Science Foundation of China,Science Foundation for Youths ( 41001165,40901133,30901163)
文摘The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.
文摘[目的]通过分析十大孔兑水土流失面积、强度及水土流失动态变化,为流域综合治理提供参考依据。[方法]基于全国土壤侵蚀遥感调查结果和全国水土流失动态监测成果,对比分析流域水土流失及其分布、动态变化。[结果]十大孔兑流域植被面积占流域面积的63.97%,以中低覆盖和低覆盖为主,分别占植被覆盖面积的48.85%和36.54%。2021年水土流失面积为4374.98 km 2,占流域面积的40.63%;与2020年、1999年和1985年相比,2021年水土流失分别减少46.32,3664.50,4958.03 km 2,水土流失主要分布在草地、林地、耕地和其他土地4个地类上,占水土流失总面积的96.69%。[结论]十大孔兑依然是黄河流域水土流失治理的难点地区,高强度侵蚀减少与年度监测成果未考虑沟道侵蚀有关;该区应坚持以“以沙棘种植为主的植被建设,以淤地坝建设为重点的工程布局,以锁边固沙为前提的治沙方针,大力推进拦沙换水试点工程”的流域综合治理策略。
