The current global or regional ionospheric models have been established for monitoring the ionospheric variations. However, the spatial and temporal resolutions are not enough to describe total electron content(TEC)...The current global or regional ionospheric models have been established for monitoring the ionospheric variations. However, the spatial and temporal resolutions are not enough to describe total electron content(TEC) variations in small scales for China. In this paper, a regional ionospheric grid model(RIGM) with high spatial-temporal resolution(0.5 0.5 and 10-min interval) in China and surrounding areas is established based on spherical harmonics expansion from dense GPS measurements provided by Crustal Movement Observation Network of China(CMONOC) and the International GNSS Service(IGS). The correlation coefficient between the estimated TEC from GPS and the ionosonde measurements is 0.97, and the root mean square(RMS) with respect to Center for Orbit Determination in Europe(CODE) Global Ionosphere Maps(GIMs) is 4.87 TECU. In addition, the impact of different spherical harmonics orders and degrees on TEC estimations are evaluated and the degree/order 6 is better. Moreover, effective ionospheric shell heights from300 km to 700 km are further assessed and the result indicates that 550 km is the most suitable for regional ionospheric modeling in China at solar maximum.展开更多
This paper is to construct a “digital local, regional, region” information framework based on the technology of “SIG” and its significance and application to the regional sustainable development evaluation system....This paper is to construct a “digital local, regional, region” information framework based on the technology of “SIG” and its significance and application to the regional sustainable development evaluation system. First, the concept of the “grid computing” and “SIG” is interpreted and discussed, then the relationship between the “grid computing” and “digital region” is analyzed, and the framework of the “digital region” is put forward. Finally, the significance and application of “grid computing” to the “region sustainable development evaluation system” are discussed.展开更多
The safety and stability study on Northeast, North, East, Northwest and Central China power grids had been carried out, which provided technical supports to planning design of regional power grids. By analyzing safety...The safety and stability study on Northeast, North, East, Northwest and Central China power grids had been carried out, which provided technical supports to planning design of regional power grids. By analyzing safety and stability under severe faults in regional power grids, revealed weaknesses on power grid configurations and measures for preventing from loss of stability were presented. In comparison of various schemes of power system safety and stability among parts of power grids, more than two recommended schemes can be chosen as reference in planning design for regional power grids. Considering the safety and stability control measures necessary for each power grids, it is believed the trunk networks of all power grids can fulfill the third criteria of Guideline for Power System Safety and Stability, while the weakness and predominated hydropower may deteriorate safety and stability of power grids. The power grid shall be regulated in line with the variation of boundary conditions.展开更多
Power industry is one of the key fields for energy conservation and emissions reduction (ECER) in China. In order to achieve the nation's overall energy consumption target and pollutant emission target set by the ...Power industry is one of the key fields for energy conservation and emissions reduction (ECER) in China. In order to achieve the nation's overall energy consumption target and pollutant emission target set by the 11th Five-Year Plan, to build the resource-conservation and environment-friendly society during the 11th Five-Year Plan period (2006-2010), it is crucial to implement the policy of "Large (units) In and Small (units) Out (LISO)" (i.e., replacing small units with large ones) and accelerate the retirement of small thermal units. According to the statistics, the power industry has made a significant progress in SO2 emission reduction during the first half of 2007. Specifically, with 18.3% growth in power generation, the SO2 emission was reduced by 5.2% compared with the same period in 2006. By the end of July 2007, the retired small units have totaled 6950 MW, 85% of which belongs to the five major power generation groups such as Guodian and Huadian. In this article, the achievements and remaining issues in Henan, Jiangsu, Sichuan Power Companies and East China Grid Company were presented and discussed thoroughly.展开更多
This study is primarily focused on Cleveland-Akron-Lorain nonattainment area in northeastern Ohio. The base year 2002 considered in this study witnessed one of the worst cases of ozone pollution in this region with oz...This study is primarily focused on Cleveland-Akron-Lorain nonattainment area in northeastern Ohio. The base year 2002 considered in this study witnessed one of the worst cases of ozone pollution in this region with ozone values exceeding previous 8-hour ozone standards of 84 ppb. The photochemical modeling system CAMx was applied to compute relative reduction factors, which were used subsequently to scale the base year (2002) values at the ozone monitoring sites to estimate the ozone design values for the year 2009 in Cleveland area for different emissions reduction scenarios. The results disclose that the largest change in the 2009 ozone design values consequent to applying auxiliary emission control strategies is between 1 and 1.5 ppb, which still left certain counties in northeastern Ohio unable to demonstrate attainment. The results are important in the development of emission control strategies in today’s context with instillation of even more stringent ozone standards and potential future increases in ozone concentrations due to climate change.展开更多
农村地区之间存在着显著的地区差异,为了指导农村电网投资,提出一种基于组合赋权和多属性边界逼近区域比较法(multi-attributive border approximation area comparison,MABAC)的差异化农网综合效益评价模型。首先,综合考虑农村地区差...农村地区之间存在着显著的地区差异,为了指导农村电网投资,提出一种基于组合赋权和多属性边界逼近区域比较法(multi-attributive border approximation area comparison,MABAC)的差异化农网综合效益评价模型。首先,综合考虑农村地区差异及乡村振兴战略对农网发展的要求,从农网投资经济效益、供电能力、基础设施情况、地区发展带动、生产生活质量、清洁低碳发展等6个方面构建农网综合效益评价指标体系;其次,基于最小化主客观权重异质性原则构建基于图模型—熵权法的组合赋权模型,并引入MABAC方法用于解决农网综合效益评价问题;最后,通过算例分析验证了所提出模型的有效性。展开更多
基金supported by the National Natural Science Foundation of China (NSFC) Project (11573052)Shanghai Science and Technology Commission Project (12DZ2273300)Key Laboratory of Planetary Sciences, Chinese Academy of Sciences
文摘The current global or regional ionospheric models have been established for monitoring the ionospheric variations. However, the spatial and temporal resolutions are not enough to describe total electron content(TEC) variations in small scales for China. In this paper, a regional ionospheric grid model(RIGM) with high spatial-temporal resolution(0.5 0.5 and 10-min interval) in China and surrounding areas is established based on spherical harmonics expansion from dense GPS measurements provided by Crustal Movement Observation Network of China(CMONOC) and the International GNSS Service(IGS). The correlation coefficient between the estimated TEC from GPS and the ionosonde measurements is 0.97, and the root mean square(RMS) with respect to Center for Orbit Determination in Europe(CODE) Global Ionosphere Maps(GIMs) is 4.87 TECU. In addition, the impact of different spherical harmonics orders and degrees on TEC estimations are evaluated and the degree/order 6 is better. Moreover, effective ionospheric shell heights from300 km to 700 km are further assessed and the result indicates that 550 km is the most suitable for regional ionospheric modeling in China at solar maximum.
文摘This paper is to construct a “digital local, regional, region” information framework based on the technology of “SIG” and its significance and application to the regional sustainable development evaluation system. First, the concept of the “grid computing” and “SIG” is interpreted and discussed, then the relationship between the “grid computing” and “digital region” is analyzed, and the framework of the “digital region” is put forward. Finally, the significance and application of “grid computing” to the “region sustainable development evaluation system” are discussed.
文摘The safety and stability study on Northeast, North, East, Northwest and Central China power grids had been carried out, which provided technical supports to planning design of regional power grids. By analyzing safety and stability under severe faults in regional power grids, revealed weaknesses on power grid configurations and measures for preventing from loss of stability were presented. In comparison of various schemes of power system safety and stability among parts of power grids, more than two recommended schemes can be chosen as reference in planning design for regional power grids. Considering the safety and stability control measures necessary for each power grids, it is believed the trunk networks of all power grids can fulfill the third criteria of Guideline for Power System Safety and Stability, while the weakness and predominated hydropower may deteriorate safety and stability of power grids. The power grid shall be regulated in line with the variation of boundary conditions.
文摘Power industry is one of the key fields for energy conservation and emissions reduction (ECER) in China. In order to achieve the nation's overall energy consumption target and pollutant emission target set by the 11th Five-Year Plan, to build the resource-conservation and environment-friendly society during the 11th Five-Year Plan period (2006-2010), it is crucial to implement the policy of "Large (units) In and Small (units) Out (LISO)" (i.e., replacing small units with large ones) and accelerate the retirement of small thermal units. According to the statistics, the power industry has made a significant progress in SO2 emission reduction during the first half of 2007. Specifically, with 18.3% growth in power generation, the SO2 emission was reduced by 5.2% compared with the same period in 2006. By the end of July 2007, the retired small units have totaled 6950 MW, 85% of which belongs to the five major power generation groups such as Guodian and Huadian. In this article, the achievements and remaining issues in Henan, Jiangsu, Sichuan Power Companies and East China Grid Company were presented and discussed thoroughly.
文摘This study is primarily focused on Cleveland-Akron-Lorain nonattainment area in northeastern Ohio. The base year 2002 considered in this study witnessed one of the worst cases of ozone pollution in this region with ozone values exceeding previous 8-hour ozone standards of 84 ppb. The photochemical modeling system CAMx was applied to compute relative reduction factors, which were used subsequently to scale the base year (2002) values at the ozone monitoring sites to estimate the ozone design values for the year 2009 in Cleveland area for different emissions reduction scenarios. The results disclose that the largest change in the 2009 ozone design values consequent to applying auxiliary emission control strategies is between 1 and 1.5 ppb, which still left certain counties in northeastern Ohio unable to demonstrate attainment. The results are important in the development of emission control strategies in today’s context with instillation of even more stringent ozone standards and potential future increases in ozone concentrations due to climate change.
文摘农村地区之间存在着显著的地区差异,为了指导农村电网投资,提出一种基于组合赋权和多属性边界逼近区域比较法(multi-attributive border approximation area comparison,MABAC)的差异化农网综合效益评价模型。首先,综合考虑农村地区差异及乡村振兴战略对农网发展的要求,从农网投资经济效益、供电能力、基础设施情况、地区发展带动、生产生活质量、清洁低碳发展等6个方面构建农网综合效益评价指标体系;其次,基于最小化主客观权重异质性原则构建基于图模型—熵权法的组合赋权模型,并引入MABAC方法用于解决农网综合效益评价问题;最后,通过算例分析验证了所提出模型的有效性。