The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper...The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper presents a new approach to rank the alternatives by G1-coefficient of variation method.The focus of this approach is the use of the combination weighing,which is able to compensate for the deficiencies in the method of evaluation index single weighing.In the case study,an appropriate evaluation index system was established to determine the evaluation value of each ventilation mode.Then the proposed approach was used to select the best development face ventilation mode.The result shows that the proposed approach is able to rank the alternative development face ventilation mode reasonably,the combination weighing method had the advantages of both subjective and objective weighing methods in that it took into consideration of both the experience and wisdom of experts,and the new changes in objective conditions.This approach provides a more reasonable and reliable procedure to analyse and evaluate different ventilation modes.展开更多
【目的】深度剖析近年来我国油菜碳足迹的时空演变及来源构成变化趋势,并提出油菜种植减排增产的可行方向,为制定油菜种植产业政策和优化种植结构提供参考依据。【方法】基于油菜投入产出数据,采用生命周期评价法测算2004—2022年我国1...【目的】深度剖析近年来我国油菜碳足迹的时空演变及来源构成变化趋势,并提出油菜种植减排增产的可行方向,为制定油菜种植产业政策和优化种植结构提供参考依据。【方法】基于油菜投入产出数据,采用生命周期评价法测算2004—2022年我国15个油菜种植省份的油菜碳足迹,分析油菜碳足迹变化特征,并有针对性提出减排策略。【结果】2004—2022年我国油菜温室气体排放总量、单位面积碳足迹和单位产量碳足迹总体上呈增长趋势,温室气体排放总量年均增长量约0.34×10^(9)kg CO_(2)eq,单位产量碳足迹年均增长量约0.01 kg CO_(2)eq/kg,单位面积碳足迹年均增长量约0.049×10^(3)kg CO_(2)eq/ha;在省份层面,长江中上游及西南、西北种植区的油菜温室气体排放总量呈正增长趋势,以湖南省增长最快,年均增长量为20.668×10^(7)kg CO_(2)eq,而江苏省、安徽省、河南省和浙江省呈下降趋势,对应的年均变化量分别为-9.925×10^(7)、-8.606×10^(7)、-2.869×10^(7)和-2.324×10^(7)kg CO_(2)eq。除重庆市外,我国主要油菜种植区的单位面积碳足迹均随时间的推移而增长,其中增长较快的有湖南省、贵州省和甘肃省,年均增长量分别为98.632、103.165和120.070 kg CO_(2)eq/ha。我国大部分油菜种植区的单位产量碳足迹随时间的推移而增加,仅重庆市、江苏省、云南省、浙江省、江西省和四川省的单位产量碳足迹呈降低趋势。从碳足迹构成来看,化肥生产和化肥施用是我国油菜种植中碳足迹的主要来源,二者的单位面积碳足迹占比合计为70.94%,其次是灌溉和人工产生的碳排放,即控制化肥和灌溉投入量是我国油菜种植减排的主要方向。我国各省油菜种植各环节单位面积碳足迹占比存在一定差异,但总体上与全国油菜单位面积碳足迹构成保持一致。【建议】积极推广油菜化肥减量增效技术,提高化肥利用效率;普及推广油菜节水节能灌溉技术,着力减少灌溉能耗;科学规划油菜产业短长期目标,优化生产区域布局。展开更多
利用高分辨率卫星海表信息和海洋历史温盐剖面数据,基于变分法重构了西北太平洋海域的三维动态温度场。与Argo(array for real-time geostrophic oceanography)温度观测剖面相比,重构温度场能够较为合理地再现海水温度的垂向变化特征,...利用高分辨率卫星海表信息和海洋历史温盐剖面数据,基于变分法重构了西北太平洋海域的三维动态温度场。与Argo(array for real-time geostrophic oceanography)温度观测剖面相比,重构温度场能够较为合理地再现海水温度的垂向变化特征,尤其是在温跃层区域,重构结果与实际观测温度廓线能够较好地吻合。文章选取了两个典型的中尺度涡旋个例,利用重构温度场分析了其从生成到衰退的整个演变过程,展示了涡旋引起的温度异常在垂直和水平分布上的动态变化。尤其是在涡旋成熟阶段,温度异常的强度和深度扩展达到最大值,表现出涡旋对海洋温跃层的显著影响。通过分析不同阶段的温度异常分布,研究揭示了冷暖核心与异常区的空间结构的演化特征。结果表明,该方法能够有效利用卫星观测海表数据重构中尺度涡旋的水下温度结构和动态演变特征,将为理解中尺度涡旋在海洋物质和热量输运提供数据支撑。展开更多
It is not reasonable that one can only use the adjoint of model in data assimilation. The simulated numerical experiment shows that for the tidal model, the result of the adjoint of equation is almost the same as that...It is not reasonable that one can only use the adjoint of model in data assimilation. The simulated numerical experiment shows that for the tidal model, the result of the adjoint of equation is almost the same as that of the adjoint of model: the averaged absolute difference of the amplitude between observations and simulation is less than 5.0 cm and that of the phase-lag is less than 5.0°. The results are both in good agreement with the observed M2 tide in the Bohai Sea and the Yellow Sea. For comparison, the traditional methods also have been used to simulate M2 tide in the Bohai Sea and the Yellow Sea. The initial guess values of the boundary conditions are given first, and then are adjusted to acquire the simulated results that are as close as possible to the observations. As the boundary conditions contain 72 values, which should be adjusted and how to adjust them can only be partially solved by adjusting them many times. The satisfied results are hard to acquire even gigantic efforts are done. Here, the automation of the treatment of the open boundary conditions is realized. The method is unique and superior to the traditional methods. It is emphasized that if the adjoint of equation is used, tedious and complicated mathematical deduction can be avoided. Therefore the adjoint of equation should attract much attention.展开更多
基金Projects(51504286,51374242)supported by the National Natural Science Foundation of ChinaProject(2015M572270)supported by China Postdoctoral Science FoundationProject(2015RS4004)supported by the Science and Technology Plan of Hunan Province,China
文摘The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper presents a new approach to rank the alternatives by G1-coefficient of variation method.The focus of this approach is the use of the combination weighing,which is able to compensate for the deficiencies in the method of evaluation index single weighing.In the case study,an appropriate evaluation index system was established to determine the evaluation value of each ventilation mode.Then the proposed approach was used to select the best development face ventilation mode.The result shows that the proposed approach is able to rank the alternative development face ventilation mode reasonably,the combination weighing method had the advantages of both subjective and objective weighing methods in that it took into consideration of both the experience and wisdom of experts,and the new changes in objective conditions.This approach provides a more reasonable and reliable procedure to analyse and evaluate different ventilation modes.
文摘【目的】深度剖析近年来我国油菜碳足迹的时空演变及来源构成变化趋势,并提出油菜种植减排增产的可行方向,为制定油菜种植产业政策和优化种植结构提供参考依据。【方法】基于油菜投入产出数据,采用生命周期评价法测算2004—2022年我国15个油菜种植省份的油菜碳足迹,分析油菜碳足迹变化特征,并有针对性提出减排策略。【结果】2004—2022年我国油菜温室气体排放总量、单位面积碳足迹和单位产量碳足迹总体上呈增长趋势,温室气体排放总量年均增长量约0.34×10^(9)kg CO_(2)eq,单位产量碳足迹年均增长量约0.01 kg CO_(2)eq/kg,单位面积碳足迹年均增长量约0.049×10^(3)kg CO_(2)eq/ha;在省份层面,长江中上游及西南、西北种植区的油菜温室气体排放总量呈正增长趋势,以湖南省增长最快,年均增长量为20.668×10^(7)kg CO_(2)eq,而江苏省、安徽省、河南省和浙江省呈下降趋势,对应的年均变化量分别为-9.925×10^(7)、-8.606×10^(7)、-2.869×10^(7)和-2.324×10^(7)kg CO_(2)eq。除重庆市外,我国主要油菜种植区的单位面积碳足迹均随时间的推移而增长,其中增长较快的有湖南省、贵州省和甘肃省,年均增长量分别为98.632、103.165和120.070 kg CO_(2)eq/ha。我国大部分油菜种植区的单位产量碳足迹随时间的推移而增加,仅重庆市、江苏省、云南省、浙江省、江西省和四川省的单位产量碳足迹呈降低趋势。从碳足迹构成来看,化肥生产和化肥施用是我国油菜种植中碳足迹的主要来源,二者的单位面积碳足迹占比合计为70.94%,其次是灌溉和人工产生的碳排放,即控制化肥和灌溉投入量是我国油菜种植减排的主要方向。我国各省油菜种植各环节单位面积碳足迹占比存在一定差异,但总体上与全国油菜单位面积碳足迹构成保持一致。【建议】积极推广油菜化肥减量增效技术,提高化肥利用效率;普及推广油菜节水节能灌溉技术,着力减少灌溉能耗;科学规划油菜产业短长期目标,优化生产区域布局。
文摘利用高分辨率卫星海表信息和海洋历史温盐剖面数据,基于变分法重构了西北太平洋海域的三维动态温度场。与Argo(array for real-time geostrophic oceanography)温度观测剖面相比,重构温度场能够较为合理地再现海水温度的垂向变化特征,尤其是在温跃层区域,重构结果与实际观测温度廓线能够较好地吻合。文章选取了两个典型的中尺度涡旋个例,利用重构温度场分析了其从生成到衰退的整个演变过程,展示了涡旋引起的温度异常在垂直和水平分布上的动态变化。尤其是在涡旋成熟阶段,温度异常的强度和深度扩展达到最大值,表现出涡旋对海洋温跃层的显著影响。通过分析不同阶段的温度异常分布,研究揭示了冷暖核心与异常区的空间结构的演化特征。结果表明,该方法能够有效利用卫星观测海表数据重构中尺度涡旋的水下温度结构和动态演变特征,将为理解中尺度涡旋在海洋物质和热量输运提供数据支撑。
文摘It is not reasonable that one can only use the adjoint of model in data assimilation. The simulated numerical experiment shows that for the tidal model, the result of the adjoint of equation is almost the same as that of the adjoint of model: the averaged absolute difference of the amplitude between observations and simulation is less than 5.0 cm and that of the phase-lag is less than 5.0°. The results are both in good agreement with the observed M2 tide in the Bohai Sea and the Yellow Sea. For comparison, the traditional methods also have been used to simulate M2 tide in the Bohai Sea and the Yellow Sea. The initial guess values of the boundary conditions are given first, and then are adjusted to acquire the simulated results that are as close as possible to the observations. As the boundary conditions contain 72 values, which should be adjusted and how to adjust them can only be partially solved by adjusting them many times. The satisfied results are hard to acquire even gigantic efforts are done. Here, the automation of the treatment of the open boundary conditions is realized. The method is unique and superior to the traditional methods. It is emphasized that if the adjoint of equation is used, tedious and complicated mathematical deduction can be avoided. Therefore the adjoint of equation should attract much attention.
