In recent years,with the advancement of geothermal heating engineering technology,the projects and scale of geothermal heating have continued to grow.At present,geothermal development and utilization projects are most...In recent years,with the advancement of geothermal heating engineering technology,the projects and scale of geothermal heating have continued to grow.At present,geothermal development and utilization projects are mostly researched on economic evaluation methods,main control factors of benefits and case analysis of project benefits.Post-evaluation of economic benefits can provide strong support for improving existing projects,adjusting projects under construction,and guiding proposed projects,but there are few studies on post-evaluation of economic benefits of completed geothermal heating projects.In order to improve the economic benefits of geothermal heating projects and change extensive management to intensive management,this paper studies the post-evaluation principles,methods and evaluation indicators of the economic benefits of hydrothermal geothermal heating projects,and take the geothermal water heating project of S community in Xianyang City as an example to carry out the post-evaluation research on economic benefits.Through research,it is suggested to carry out post-economic evaluation of geothermal utilization projects that have been completed and run for 3 to 5 years.In order to do a good job in the post-evaluation of economic benefits,the evaluators should continue to track the progress of the project,collect and analyze various historical data in a timely manner,and select a variety of methods for prediction,comparison and mutual correction.In order to fully reflect the benefits of geothermal heating,the indirect benefit evaluation of energy conservation and emission reduction of geothermal heating projects will be strengthened in the future.展开更多
玉米是我国第一大粮食作物,对我国粮食安全影响深远。依据重心模型,运用地理信息系统(geographic information system,GIS)测算了1999—2022年我国玉米生产重心与消费重心的移动方向、距离、速度等变化特征,利用耦合模型分析玉米生产与...玉米是我国第一大粮食作物,对我国粮食安全影响深远。依据重心模型,运用地理信息系统(geographic information system,GIS)测算了1999—2022年我国玉米生产重心与消费重心的移动方向、距离、速度等变化特征,利用耦合模型分析玉米生产与消费的空间匹配性,并结合自然、经济、政治等因素,研究其变动原因。结果表明,1999—2022年我国玉米生产重心整体呈现从西南-东北移动的特点,共移动了148.55 km,平均移动速度为6.46 km·a^(-1);玉米消费重心总体呈现从西南-东北-东南-西南-东北环形变动的特点,阶段性特征明显;生产与消费重心的耦合距离呈先升高后降低的总体特点,但增幅远大于降幅。耦合距离由471.02 km(1999年)变为513.02 km(2022年),其中2013年二者的重心耦合距离达最大值,为557.91 km。2020年以来,玉米生产与消费的耦合距离又出现增加趋势,空间匹配性再度下降,为新时代粮食安全带来了挑战。因此,提出优化玉米区域利益协调机制、构建多主体利益联结机制和支持政策体系、优化玉米区域生产与消费空间格局、实施区域差异性的粮食政策等政策建议。展开更多
文摘In recent years,with the advancement of geothermal heating engineering technology,the projects and scale of geothermal heating have continued to grow.At present,geothermal development and utilization projects are mostly researched on economic evaluation methods,main control factors of benefits and case analysis of project benefits.Post-evaluation of economic benefits can provide strong support for improving existing projects,adjusting projects under construction,and guiding proposed projects,but there are few studies on post-evaluation of economic benefits of completed geothermal heating projects.In order to improve the economic benefits of geothermal heating projects and change extensive management to intensive management,this paper studies the post-evaluation principles,methods and evaluation indicators of the economic benefits of hydrothermal geothermal heating projects,and take the geothermal water heating project of S community in Xianyang City as an example to carry out the post-evaluation research on economic benefits.Through research,it is suggested to carry out post-economic evaluation of geothermal utilization projects that have been completed and run for 3 to 5 years.In order to do a good job in the post-evaluation of economic benefits,the evaluators should continue to track the progress of the project,collect and analyze various historical data in a timely manner,and select a variety of methods for prediction,comparison and mutual correction.In order to fully reflect the benefits of geothermal heating,the indirect benefit evaluation of energy conservation and emission reduction of geothermal heating projects will be strengthened in the future.