The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the ent...The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the entire country. Based on the concept and macro-scale digital elevation model datum and ARC/INFO software, the RDLS at a 10 km×10 km grid size of China is extracted. This paper depicts systemically the spatial distributions of RDLS through analyzing the ratio structure and altitudinal characters of RDLS in China. The conclusions are drawn as follows： the RDLS in more than 63% of the area is less than one （1） （relative altitude is less than 500 m）, reflecting the fact that most of RDLS in China is low. In general, the RDLS in the west is larger than that in the east and so is the south than that of the north in China. The RDLS decreases with the increase of longitude and latitude and the change of RDLS at the latitudes of 28°N, 35°N, 42°N, as well as at the longitudes of 85°E, 102°E, 115°E could reflect the three major ladders of China. In the vertical direction, the RDLS increases with the increase of altitude. Analysis of the correlation between RDLS and population distribution in China and its regional difference shows that the R2 value between RDLS and population density is 0.91 and RDLS is an important factor influencing the spatial distribution of population. More than 85% of the people in China live in areas where the RDLS is less than one （1）, while the population in areas with RDLS greater than 3 accounts only for 0.57% of the total. The regional difference of correlation between RDLS and population within China is significant and such correlation is significant in Central China and South China and weak in Inner Mongolia and Tibet.展开更多
采用同源建模的方法构建了斑马鱼γ-氨基丁酸A型（GABAA）受体和果蝇RDL（resistance to dieldrin）受体跨膜区的三维结构，研究了氟虫腈在两个受体中作用位点的差异；采用分子对接和分子动力学方法，探讨了氟虫腈与斑马鱼GABAA受体和果...采用同源建模的方法构建了斑马鱼γ-氨基丁酸A型（GABAA）受体和果蝇RDL（resistance to dieldrin）受体跨膜区的三维结构，研究了氟虫腈在两个受体中作用位点的差异；采用分子对接和分子动力学方法，探讨了氟虫腈与斑马鱼GABAA受体和果蝇RDL受体的结合模式，并比较了氟虫腈与两个受体作用的差异性。结果表明：斑马鱼 GABAA受体和氟虫腈作用位点的结构与果蝇RDL受体和氟虫腈作用位点的结构存在一定的差异，果蝇 RDL 受体中的 Ala301对应斑马鱼GABAA受体α1亚基中的Val284和γ2亚基中的Ser306，氨基酸构象的差异较大；氟虫腈与斑马鱼GABAA受体的结合位点靠近胞内区一端，而与果蝇RDL受体的结合位点则位于受体第二跨膜区的Ala301～Leu308区域内。复合物分子动力学模拟结果表明，在模拟过程中，两个受体与氟虫腈复合物体系的势能可很快达到平衡状态。斑马鱼GABAA受体与氟虫腈之间形成4个氢键，其中概率大于60％的氢键有2个；而尽管果蝇RDL受体与氟虫腈形成了6个氢键，但只有1个氢键的概率大于50％，其复合物结合的稳定性比前者低。展开更多
基金Knowledge Innovation Project of the CAS,No.KZCX2-YW-323
文摘The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the entire country. Based on the concept and macro-scale digital elevation model datum and ARC/INFO software, the RDLS at a 10 km×10 km grid size of China is extracted. This paper depicts systemically the spatial distributions of RDLS through analyzing the ratio structure and altitudinal characters of RDLS in China. The conclusions are drawn as follows： the RDLS in more than 63% of the area is less than one （1） （relative altitude is less than 500 m）, reflecting the fact that most of RDLS in China is low. In general, the RDLS in the west is larger than that in the east and so is the south than that of the north in China. The RDLS decreases with the increase of longitude and latitude and the change of RDLS at the latitudes of 28°N, 35°N, 42°N, as well as at the longitudes of 85°E, 102°E, 115°E could reflect the three major ladders of China. In the vertical direction, the RDLS increases with the increase of altitude. Analysis of the correlation between RDLS and population distribution in China and its regional difference shows that the R2 value between RDLS and population density is 0.91 and RDLS is an important factor influencing the spatial distribution of population. More than 85% of the people in China live in areas where the RDLS is less than one （1）, while the population in areas with RDLS greater than 3 accounts only for 0.57% of the total. The regional difference of correlation between RDLS and population within China is significant and such correlation is significant in Central China and South China and weak in Inner Mongolia and Tibet.
