With the rapid development of economy,the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser.This article based on the decoupling theory takes the situatio...With the rapid development of economy,the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser.This article based on the decoupling theory takes the situations of cultivated land occupation by construction and economic growth in China from 1998 to 2007 as an example to evaluate and analyze the decoupling.The conclusions are drawn as follows.First,the article applies IU curve and gross method.The decoupling status by gross method,in contrast to that by IU curve,can express the pressure from cultivated land occupation better and is similar to the decoupling status based on the model of decoupling in this article.Second,in most provinces of China,the relationship between the cultivated land occupation by construction and economic growth has transformed from expansive negative decoupling to strong decoupling.In general,the transformation was firstly from economically advanced eastern municipalities under the central government directly,then to economically advanced eastern coastal provinces,and lastly to central,western and northeastern regions.Third,the decoupling status was relative to contemporaneous policies and laws on cultivated land protection and regional development planning.Their effect is obvious and positive.展开更多
Nodes play different roles or have different functions in many natural and social networks.In this paper,a simple model with different types of nodes and deterministic selective linking rule is proposed.The structural...Nodes play different roles or have different functions in many natural and social networks.In this paper,a simple model with different types of nodes and deterministic selective linking rule is proposed.The structural properties by theoretical predictions are investigated that the given model exhibits a power-law distribution.展开更多
基金supported by the National Natural Science Foundation of China (Grant no.70673097)
文摘With the rapid development of economy,the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser.This article based on the decoupling theory takes the situations of cultivated land occupation by construction and economic growth in China from 1998 to 2007 as an example to evaluate and analyze the decoupling.The conclusions are drawn as follows.First,the article applies IU curve and gross method.The decoupling status by gross method,in contrast to that by IU curve,can express the pressure from cultivated land occupation better and is similar to the decoupling status based on the model of decoupling in this article.Second,in most provinces of China,the relationship between the cultivated land occupation by construction and economic growth has transformed from expansive negative decoupling to strong decoupling.In general,the transformation was firstly from economically advanced eastern municipalities under the central government directly,then to economically advanced eastern coastal provinces,and lastly to central,western and northeastern regions.Third,the decoupling status was relative to contemporaneous policies and laws on cultivated land protection and regional development planning.Their effect is obvious and positive.
文摘Nodes play different roles or have different functions in many natural and social networks.In this paper,a simple model with different types of nodes and deterministic selective linking rule is proposed.The structural properties by theoretical predictions are investigated that the given model exhibits a power-law distribution.
