Star River(or Star Bay),an elite works of Hong Yu Group,is located in Sijixinghe Road,Chaoyang District,Beijing.It is a distinguished residence area,occupying land of 300 thousand sq.meters.The north side is a forest ...Star River(or Star Bay),an elite works of Hong Yu Group,is located in Sijixinghe Road,Chaoyang District,Beijing.It is a distinguished residence area,occupying land of 300 thousand sq.meters.The north side is a forest garden with 1600 or more mu,the eastern side is a green belt with more than 2000 mu.展开更多
The process of rapid urbanization in China features two opposing trends： declining rural population and increasing rural residential land, especially in southern hilly areas. The extraction and analysis of residentia...The process of rapid urbanization in China features two opposing trends： declining rural population and increasing rural residential land, especially in southern hilly areas. The extraction and analysis of residential land in rural China represents an important application for remote sensing technology. The study aimed to discover rural residential land information using RapidEye satellite imagery, taking Taihe County as the research area in the hilly region of southern China. Based on multiple experiments, classification was conducted with an optimal image segmentation scale set to 200. The object-oriented classification rule set was constructed using the customized parameters NDVI, NDWI, brightness, and length/width. The areas of residential land and other land use types were interpreted by varying the parameter values for classification rule sets. Finally, validation and accuracy evaluations were carried out. The overall accuracy of residential land interpretation is 78.40%, and producer＇s accuracy and user＇s accuracy are 68.75% and 77.33%, respectively. The results indicate that RapidEye provides a suitable data source for extraction of rural residential land using an object-oriented approach. Compared with the second national land survey of China, the classification gave an absolute difference of 93.67 ha residential land within the study area. Recognition errors occurred mainly in regions adjacent to the boundaries between residential land and other types of land.展开更多
HD40307g is the closest potentially habitable planet discovered today orbiting a K2V star and will be a prime target for future TPF-like missions if its existence is confirmed.Although the atmosphere of HD40307g shoul...HD40307g is the closest potentially habitable planet discovered today orbiting a K2V star and will be a prime target for future TPF-like missions if its existence is confirmed.Although the atmosphere of HD40307g should be denser and contain more CO2 judging from the amount of radiation it receives from its star,it is unknown how dense and how much CO2 the planetary atmosphere should have.Thus more knowledge on its atmosphere is useful.For HD40307g to have Earth-like climate(288 K global mean surface temperature),we obtain the following combination of atmospheric pressure and CO2 mixing ratio:(1)10-bar+3%CO2;(2)5-bar+10%CO2;(3)3-bar+30%CO2.展开更多
文摘Star River(or Star Bay),an elite works of Hong Yu Group,is located in Sijixinghe Road,Chaoyang District,Beijing.It is a distinguished residence area,occupying land of 300 thousand sq.meters.The north side is a forest garden with 1600 or more mu,the eastern side is a green belt with more than 2000 mu.
基金National Natural Science Foundation of China(41301474)National Science&Technology Infrastructure Work Special Projects of China(2011FY110400,2013FY114600)the China Postdoctoral Science Foundation(2013M530708,2014T70114)
文摘The process of rapid urbanization in China features two opposing trends： declining rural population and increasing rural residential land, especially in southern hilly areas. The extraction and analysis of residential land in rural China represents an important application for remote sensing technology. The study aimed to discover rural residential land information using RapidEye satellite imagery, taking Taihe County as the research area in the hilly region of southern China. Based on multiple experiments, classification was conducted with an optimal image segmentation scale set to 200. The object-oriented classification rule set was constructed using the customized parameters NDVI, NDWI, brightness, and length/width. The areas of residential land and other land use types were interpreted by varying the parameter values for classification rule sets. Finally, validation and accuracy evaluations were carried out. The overall accuracy of residential land interpretation is 78.40%, and producer＇s accuracy and user＇s accuracy are 68.75% and 77.33%, respectively. The results indicate that RapidEye provides a suitable data source for extraction of rural residential land using an object-oriented approach. Compared with the second national land survey of China, the classification gave an absolute difference of 93.67 ha residential land within the study area. Recognition errors occurred mainly in regions adjacent to the boundaries between residential land and other types of land.
基金supported by the National Natural Science Foundation of China(Grant No.41175039/D0504)the Knowledge Innovation Project of Chinese Academyof Sciences(Grant No.KJCX2-YW-T27)the John Templeton Foundation
文摘HD40307g is the closest potentially habitable planet discovered today orbiting a K2V star and will be a prime target for future TPF-like missions if its existence is confirmed.Although the atmosphere of HD40307g should be denser and contain more CO2 judging from the amount of radiation it receives from its star,it is unknown how dense and how much CO2 the planetary atmosphere should have.Thus more knowledge on its atmosphere is useful.For HD40307g to have Earth-like climate(288 K global mean surface temperature),we obtain the following combination of atmospheric pressure and CO2 mixing ratio:(1)10-bar+3%CO2;(2)5-bar+10%CO2;(3)3-bar+30%CO2.
