Let ωα （α=1,…,n） be the holomorphic invariant forms introduced by the author previously ona bounded domain D in Cn for n ≥ 2. Set ωα=（i/2）α ωα.Then for any complex surface S in D we have ω2/1｜S≥ω2｜s.
The problem of land ecological security directly threatens the sustainable development of many regions,and exploring the spatio-temporal characteristics of land ecological security is helpful for analyzing the land ec...The problem of land ecological security directly threatens the sustainable development of many regions,and exploring the spatio-temporal characteristics of land ecological security is helpful for analyzing the land ecological patterns between regions and over time.Based on the interpretation of remote sensing image data for Tianjin in 1980,2000,2010 and 2019,supported by software such as ArcGIS and GeoDa,the changes of land use in the study area are calculated by using the land use dynamic degree.Then,the land ecological security index and spatial autocorrelation analysis methods are used to study the spatial correlations and internal heterogeneity of land ecological security in each district in Tianjin.The results show that:(1)The land use of Tianjin has changed dramatically in the past 40 years:the building land has been expanding,while the farmland and barren have been shrinking continuously.(2)The overall level of land ecological security is in the high security area,and Jizhou District is the highest,while the Central areas and Binhai are low.(3)The spatial heterogeneity of land ecological security is not obvious,but the spatial agglomeration is strong.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.A01010501 and 10731080)
文摘Let ωα （α=1,…,n） be the holomorphic invariant forms introduced by the author previously ona bounded domain D in Cn for n ≥ 2. Set ωα=（i/2）α ωα.Then for any complex surface S in D we have ω2/1｜S≥ω2｜s.
基金Tianjin Art and Science Planning Project(D16007)。
文摘The problem of land ecological security directly threatens the sustainable development of many regions,and exploring the spatio-temporal characteristics of land ecological security is helpful for analyzing the land ecological patterns between regions and over time.Based on the interpretation of remote sensing image data for Tianjin in 1980,2000,2010 and 2019,supported by software such as ArcGIS and GeoDa,the changes of land use in the study area are calculated by using the land use dynamic degree.Then,the land ecological security index and spatial autocorrelation analysis methods are used to study the spatial correlations and internal heterogeneity of land ecological security in each district in Tianjin.The results show that:(1)The land use of Tianjin has changed dramatically in the past 40 years:the building land has been expanding,while the farmland and barren have been shrinking continuously.(2)The overall level of land ecological security is in the high security area,and Jizhou District is the highest,while the Central areas and Binhai are low.(3)The spatial heterogeneity of land ecological security is not obvious,but the spatial agglomeration is strong.
