The policy of the Chinese government concerning the horizontal expansion of the cultivated land through the reclamation of desert soils result in a total increase of 665.985 km 2 during the period 1987\|1999 in North ...The policy of the Chinese government concerning the horizontal expansion of the cultivated land through the reclamation of desert soils result in a total increase of 665.985 km 2 during the period 1987\|1999 in North Shaanxi. This increase is less than the loss in arable land by urbanization. The accelerated rate of change in agricultural areas calls for more rapid surveys of urbanization and loss of arable land. Remote sensing has a number of advantages over ground\|based methods for such surveys. The multi\|scale concept of remote sensing data help us study the problem in four towns. Several maps were produced to analyze the situation of urban coverage in different times. The evaluation of the status, rate and risk of urbanization are based on an accepted average of urban increase as 2% of population growth per year.展开更多
Surface charge distribution of particles is the fundamental problem for adsorption and desorption between sediment and contaminant. In this paper, we take quartz sand for example to measure its micro-morphology and su...Surface charge distribution of particles is the fundamental problem for adsorption and desorption between sediment and contaminant. In this paper, we take quartz sand for example to measure its micro-morphology and surface charge distribution using the phase mode of the electrical force microscope. Then the statistical relation of micro-morphology and surface charge distribution is obtained. Results show that quartz sand possesses complex surface morphology, which has great impact on the charge distribution. Positive and negative charges mostly concentrate on the saddle, convex and concave parts of the surface, while distribute less in the groove, ridge and flat parts. This experiment provides a new method for understanding the process of flocculation in coastal and estuarine zone.展开更多
文摘The policy of the Chinese government concerning the horizontal expansion of the cultivated land through the reclamation of desert soils result in a total increase of 665.985 km 2 during the period 1987\|1999 in North Shaanxi. This increase is less than the loss in arable land by urbanization. The accelerated rate of change in agricultural areas calls for more rapid surveys of urbanization and loss of arable land. Remote sensing has a number of advantages over ground\|based methods for such surveys. The multi\|scale concept of remote sensing data help us study the problem in four towns. Several maps were produced to analyze the situation of urban coverage in different times. The evaluation of the status, rate and risk of urbanization are based on an accepted average of urban increase as 2% of population growth per year.
基金supported by the National Natural Science Foundation of China (Grant No. 50909095)Chinese Universities Scientific Fund (Grant No. 2011JS131)
文摘Surface charge distribution of particles is the fundamental problem for adsorption and desorption between sediment and contaminant. In this paper, we take quartz sand for example to measure its micro-morphology and surface charge distribution using the phase mode of the electrical force microscope. Then the statistical relation of micro-morphology and surface charge distribution is obtained. Results show that quartz sand possesses complex surface morphology, which has great impact on the charge distribution. Positive and negative charges mostly concentrate on the saddle, convex and concave parts of the surface, while distribute less in the groove, ridge and flat parts. This experiment provides a new method for understanding the process of flocculation in coastal and estuarine zone.
