食物消费是城市养分流动的重要环节,以厦门市为例,分析了1988—2009年居民食物氮素消费的变化特点,分析与其变化相关的经济、社会因素,并探讨了居民食物氮素消费变化所带来的环境负荷。研究结果表明,厦门市人均食物氮消费量变化与食物...食物消费是城市养分流动的重要环节,以厦门市为例,分析了1988—2009年居民食物氮素消费的变化特点,分析与其变化相关的经济、社会因素,并探讨了居民食物氮素消费变化所带来的环境负荷。研究结果表明,厦门市人均食物氮消费量变化与食物消费量变化并不完全一致,人均氮消费量2000年以前维持在3.29 kg N.人-1.a-1,2000年以后呈现波动性的增长,2004年达到最高值4.00 kg N.人-1.a-1。厦门市食物氮素消费总量增长幅度较大,由1988年的0.54万t增至2009年的1.50万t。同时,粮食在食物氮消费量中所占比例由45.5%下降到15.9%。畜禽肉、奶制品所占比例分别由25.0%和0.4%上升至29.8%和8.8%。通过将相关经济、社会因素与居民食物氮消费量进行相关性分析表明,人均可支配收入、食物价格指数、具有大学学历以上人口比重均与其联系较为密切,呈正相关;恩格尔系数、平均家庭人口数与居民食物氮消费量呈负相关。通过选取1988、1994、2001、2008年分析居民食物氮素消费造成的环境氮负荷发现,由其带来的环境氮负荷量由3509.12t增加至7629.36t,约90%的氮素进入了土壤和水体。其中,进入土壤的氮素占进入环境氮总量的比例由37%增长到60%,进入水体的氮素比例由57%降至35%。展开更多
为实现主动配电网对可再生能源最大程度的消纳,提出了一种主动配电网分布式能源分区消纳的协调控制策略。依据分段开关位置将配电网划分为若干含有分布式能源的自治区域,以可再生能源最大消纳情况下成本最低为目标进行全局优化;每个区...为实现主动配电网对可再生能源最大程度的消纳,提出了一种主动配电网分布式能源分区消纳的协调控制策略。依据分段开关位置将配电网划分为若干含有分布式能源的自治区域,以可再生能源最大消纳情况下成本最低为目标进行全局优化;每个区域接受全局优化潮流算法提供的优化目标,在此基础上根据馈线功率误差指标(feeder control error,FCE)计算的功率偏差总额,仅考虑自治区域局部拓扑,采用配网直流潮流运算,利用区域内的分布式电源快速实现自治区域中馈线功率误差(FCE)的分配和消纳,最终实现FCE等于零;无法完成区域目标时相邻区域相互通信协助补足差额。最后,通过双馈线7个自治区域的系统算例验证了算法的有效性。展开更多
From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship betw...From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward.展开更多
The plant water consumption and irrigation management are the core issue of the sustainable growing of the Tarim Desert Highway shelterbelt in the hyperaride Taklimakan Desert. The stem sap flow, water status and wate...The plant water consumption and irrigation management are the core issue of the sustainable growing of the Tarim Desert Highway shelterbelt in the hyperaride Taklimakan Desert. The stem sap flow, water status and water consumption of shelterbelt plants were studied, then, the issue of the water save in the process of shelterbelt irrigation management was discussed by measuring the sap flow of shelterbelt plants with a stem sap flow gauge. The stem sap flow exhibited a distinct diurnal course with maximum values between 10:00 and 15:00, and minimum values between 00:00 and 03:00. Generally, sap flow was lower at night than during the day. The daily average stem sap flow of Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron (diameter 1.9―2.0 cm) was 67.2 g·h-1, 77.05 g·h-1 and 61.54 g·h-1 respectively. The sap flow was influenced by environmental factors, and the solar radiation, wind velocity, temperature and relative humidity were significantly correlative with plant stem sap flow. The annual water consumption of 8-a Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron was 1937.80 kg, 1253.39 kg and 1026.96 kg, while daily average water consumption was 9.69 kg, 6.27 kg and 5.13 kg respectively. Under drip irrigation, soil moisture content of the shelterbelt in different months indicated no obvious fluctuation, and soil moisture was adequate. The predawn and midday plant water potential reflected that the plant water status was in good conditions. There is still some water-saving space if optimizing the present water management, integrating water resources conservation and protection performance.展开更多
文摘食物消费是城市养分流动的重要环节,以厦门市为例,分析了1988—2009年居民食物氮素消费的变化特点,分析与其变化相关的经济、社会因素,并探讨了居民食物氮素消费变化所带来的环境负荷。研究结果表明,厦门市人均食物氮消费量变化与食物消费量变化并不完全一致,人均氮消费量2000年以前维持在3.29 kg N.人-1.a-1,2000年以后呈现波动性的增长,2004年达到最高值4.00 kg N.人-1.a-1。厦门市食物氮素消费总量增长幅度较大,由1988年的0.54万t增至2009年的1.50万t。同时,粮食在食物氮消费量中所占比例由45.5%下降到15.9%。畜禽肉、奶制品所占比例分别由25.0%和0.4%上升至29.8%和8.8%。通过将相关经济、社会因素与居民食物氮消费量进行相关性分析表明,人均可支配收入、食物价格指数、具有大学学历以上人口比重均与其联系较为密切,呈正相关;恩格尔系数、平均家庭人口数与居民食物氮消费量呈负相关。通过选取1988、1994、2001、2008年分析居民食物氮素消费造成的环境氮负荷发现,由其带来的环境氮负荷量由3509.12t增加至7629.36t,约90%的氮素进入了土壤和水体。其中,进入土壤的氮素占进入环境氮总量的比例由37%增长到60%,进入水体的氮素比例由57%降至35%。
文摘为实现主动配电网对可再生能源最大程度的消纳,提出了一种主动配电网分布式能源分区消纳的协调控制策略。依据分段开关位置将配电网划分为若干含有分布式能源的自治区域,以可再生能源最大消纳情况下成本最低为目标进行全局优化;每个区域接受全局优化潮流算法提供的优化目标,在此基础上根据馈线功率误差指标(feeder control error,FCE)计算的功率偏差总额,仅考虑自治区域局部拓扑,采用配网直流潮流运算,利用区域内的分布式电源快速实现自治区域中馈线功率误差(FCE)的分配和消纳,最终实现FCE等于零;无法完成区域目标时相邻区域相互通信协助补足差额。最后,通过双馈线7个自治区域的系统算例验证了算法的有效性。
基金Item Sponsored by National Basic Research Programof China (200002600)
文摘From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward.
基金Supported by Knowledge Innovation Project of Chinese Academy of Science (Grant No. KZCX3-SW-342-02)Key Project of the "West China Science and Technology Development Action" by Ministry of Science and Technology of China (Grant No. 2004BA901A21-1)
文摘The plant water consumption and irrigation management are the core issue of the sustainable growing of the Tarim Desert Highway shelterbelt in the hyperaride Taklimakan Desert. The stem sap flow, water status and water consumption of shelterbelt plants were studied, then, the issue of the water save in the process of shelterbelt irrigation management was discussed by measuring the sap flow of shelterbelt plants with a stem sap flow gauge. The stem sap flow exhibited a distinct diurnal course with maximum values between 10:00 and 15:00, and minimum values between 00:00 and 03:00. Generally, sap flow was lower at night than during the day. The daily average stem sap flow of Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron (diameter 1.9―2.0 cm) was 67.2 g·h-1, 77.05 g·h-1 and 61.54 g·h-1 respectively. The sap flow was influenced by environmental factors, and the solar radiation, wind velocity, temperature and relative humidity were significantly correlative with plant stem sap flow. The annual water consumption of 8-a Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron was 1937.80 kg, 1253.39 kg and 1026.96 kg, while daily average water consumption was 9.69 kg, 6.27 kg and 5.13 kg respectively. Under drip irrigation, soil moisture content of the shelterbelt in different months indicated no obvious fluctuation, and soil moisture was adequate. The predawn and midday plant water potential reflected that the plant water status was in good conditions. There is still some water-saving space if optimizing the present water management, integrating water resources conservation and protection performance.
