通过收集相关基础资料和数据,基于中国土壤流失方程计算出四川省级水土流失动态监测区土壤侵蚀状况,并将监测结果与2011年第一次全国水利普查水土保持情况普查成果进行对比分析。结果表明:监测区水土流失面积为36945.20 km 2,占动态监...通过收集相关基础资料和数据,基于中国土壤流失方程计算出四川省级水土流失动态监测区土壤侵蚀状况,并将监测结果与2011年第一次全国水利普查水土保持情况普查成果进行对比分析。结果表明:监测区水土流失面积为36945.20 km 2,占动态监测区总面积的27.16%,区内整体土壤侵蚀程度较轻,但侵蚀分布空间异质性明显,局部地区仍存在严重水土流失;监测区水土流失面积减少率为4.85%,且水土流失强度由高强度转向低强度,但水土流失消长情况具有空间差异性,川西地区部分区县水土流失面积仍有小幅增加。近年来四川省水土流失治理力度加大,对改善监测区水土流失起到了积极作用,但局部地区仍要加强水土流失预防监督工作。展开更多
为了应对综合能源系统(Integrated Energy System,IES)中供能设备存在的潜在故障风险,建立了基于运行状态的设备故障概率模型以及基于负载率的设备故障严重度模型,表征设备不同运行状态与系统安全风险关联关系。在此基础上,以运行成本...为了应对综合能源系统(Integrated Energy System,IES)中供能设备存在的潜在故障风险,建立了基于运行状态的设备故障概率模型以及基于负载率的设备故障严重度模型,表征设备不同运行状态与系统安全风险关联关系。在此基础上,以运行成本和风险值为优化目标,综合考虑电力、天然气和热力管网以及机组出力等多种约束,建立了IES多目标优化运行模型。运用二阶锥松弛、分段线性化和宽容分层序列法将该模型处理为混合整数二阶锥规划模型,并用宽容度表征系统对风险的接受程度。算例分析结果表明该模型求取的运行策略可以较好地兼顾系统运行安全性与经济性,验证了所提模型和方法的合理性和有效性。展开更多
Under global warming, storm events tend to intensify, particularly in monsoon-affected regions. As an important agricultural area in China, the purple soil region in the Sichuan Basin, where it has a prevailing monsoo...Under global warming, storm events tend to intensify, particularly in monsoon-affected regions. As an important agricultural area in China, the purple soil region in the Sichuan Basin, where it has a prevailing monsoon climate, is threatened by serious soil erosion. Tillage operations alter runoff and soil erosion processes on croplands by changing the physical properties of the soil surface. To clarify the relationship between tillage and soil erosion in the purple soil region, three different tillage practices in this region were investigated at the plot scale over 4 years： bare land with minimum tillage （BL）, conventional tillage （CT） and seasonal no-tillage ridges （SNTR） which was initially designed to prevent soil erosion by contoured ridges and no-tillage techniques. The results showed that although there were no significant differences in the surface runoff and soil erosion among the three oractices, BL caused relatively high surface runoff and soil erosion, followed by CT and SNTR. Classification and comparison of the rainfall events based on cluster analysis （CA） verified that the surface runoff was not significantly different between most intensive event and long intensive events but was significantly different between most intensive and short and medium-duration events. Only the rainfall events with the highest rainfall intensity could trigger serious soil erosion, up to 1000 kg ha^-1 in the region. Further detailed investigations on the effects of tillage operations on the soil erosion in a subtropical region with a monsoon climate are needed to provide a basis for modeling catchments and designing better management practices.展开更多
文摘通过收集相关基础资料和数据,基于中国土壤流失方程计算出四川省级水土流失动态监测区土壤侵蚀状况,并将监测结果与2011年第一次全国水利普查水土保持情况普查成果进行对比分析。结果表明:监测区水土流失面积为36945.20 km 2,占动态监测区总面积的27.16%,区内整体土壤侵蚀程度较轻,但侵蚀分布空间异质性明显,局部地区仍存在严重水土流失;监测区水土流失面积减少率为4.85%,且水土流失强度由高强度转向低强度,但水土流失消长情况具有空间差异性,川西地区部分区县水土流失面积仍有小幅增加。近年来四川省水土流失治理力度加大,对改善监测区水土流失起到了积极作用,但局部地区仍要加强水土流失预防监督工作。
文摘为了应对综合能源系统(Integrated Energy System,IES)中供能设备存在的潜在故障风险,建立了基于运行状态的设备故障概率模型以及基于负载率的设备故障严重度模型,表征设备不同运行状态与系统安全风险关联关系。在此基础上,以运行成本和风险值为优化目标,综合考虑电力、天然气和热力管网以及机组出力等多种约束,建立了IES多目标优化运行模型。运用二阶锥松弛、分段线性化和宽容分层序列法将该模型处理为混合整数二阶锥规划模型,并用宽容度表征系统对风险的接受程度。算例分析结果表明该模型求取的运行策略可以较好地兼顾系统运行安全性与经济性,验证了所提模型和方法的合理性和有效性。
基金support of this study was provided by the National Natural Science Foundation of China (Grant No. 41371241 and 41101202)the Western Development Plan of Chinese Academy of Sciences (Grant No. KZCX2XB3-09)the National Basic Research Program of the Ministry of Science and Technology of China (Grant No. 2012CB417101)
文摘Under global warming, storm events tend to intensify, particularly in monsoon-affected regions. As an important agricultural area in China, the purple soil region in the Sichuan Basin, where it has a prevailing monsoon climate, is threatened by serious soil erosion. Tillage operations alter runoff and soil erosion processes on croplands by changing the physical properties of the soil surface. To clarify the relationship between tillage and soil erosion in the purple soil region, three different tillage practices in this region were investigated at the plot scale over 4 years： bare land with minimum tillage （BL）, conventional tillage （CT） and seasonal no-tillage ridges （SNTR） which was initially designed to prevent soil erosion by contoured ridges and no-tillage techniques. The results showed that although there were no significant differences in the surface runoff and soil erosion among the three oractices, BL caused relatively high surface runoff and soil erosion, followed by CT and SNTR. Classification and comparison of the rainfall events based on cluster analysis （CA） verified that the surface runoff was not significantly different between most intensive event and long intensive events but was significantly different between most intensive and short and medium-duration events. Only the rainfall events with the highest rainfall intensity could trigger serious soil erosion, up to 1000 kg ha^-1 in the region. Further detailed investigations on the effects of tillage operations on the soil erosion in a subtropical region with a monsoon climate are needed to provide a basis for modeling catchments and designing better management practices.
