The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research relate...The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research related to rural areas, agriculture and farmers had remained as the prominent parts for a long period and would continue to be prominent in the future to build China into a moderately prosperous nation in an all-round way. Chinese rural area had constantly experienced three significant system reforms since 1978, namely the reform of rural management system, the rural tax and fee reform and the rural comprehensive reform. This paper attempted to analyze the theoretic framework and the content structure of the comprehensive rural reform since it was the higher stage of rural institutional vicissitude, which had changed the governance and operation system and thus promoted the great changes to fundamental social and economic system in rural areas. The theoretic framework of comprehensive rural reform covered three aspects in its content, namely the rural governance theory, the government function theory and the public finance theory. The comprehensive rural reform was a complicated system engineering with multiple dimensions and targets mainly including rural political restructuring, rural economic restructuring and rural public products allocation restructuring. The reform had focused on enhancing the vitality of agricultural and rural development, breaking through the urban and rural binary system, and further reducing the disparity between cities and countrysides, so as to realize the urban-rural integration. It was necessary to clarify and understand the key mechanism and intrinsic logic of the rural comprehensive reform, which was helpful to establish the foundation constituted by scientific methodology to implement the reform and evaluation criterion to judge the reform performance.展开更多
Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way t...Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.展开更多
基金Supported by the Funding from the Doctoral Research Foundation of Zhaoqing University(2013)
文摘The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research related to rural areas, agriculture and farmers had remained as the prominent parts for a long period and would continue to be prominent in the future to build China into a moderately prosperous nation in an all-round way. Chinese rural area had constantly experienced three significant system reforms since 1978, namely the reform of rural management system, the rural tax and fee reform and the rural comprehensive reform. This paper attempted to analyze the theoretic framework and the content structure of the comprehensive rural reform since it was the higher stage of rural institutional vicissitude, which had changed the governance and operation system and thus promoted the great changes to fundamental social and economic system in rural areas. The theoretic framework of comprehensive rural reform covered three aspects in its content, namely the rural governance theory, the government function theory and the public finance theory. The comprehensive rural reform was a complicated system engineering with multiple dimensions and targets mainly including rural political restructuring, rural economic restructuring and rural public products allocation restructuring. The reform had focused on enhancing the vitality of agricultural and rural development, breaking through the urban and rural binary system, and further reducing the disparity between cities and countrysides, so as to realize the urban-rural integration. It was necessary to clarify and understand the key mechanism and intrinsic logic of the rural comprehensive reform, which was helpful to establish the foundation constituted by scientific methodology to implement the reform and evaluation criterion to judge the reform performance.
基金Project(2021YFC2902102)supported by the National Key Research and Development Program of ChinaProject(52374142)supported by the National Natural Science Foundation of ChinaProject(JSTU-2022-066)supported by the Young Talent Support Project of Jiangsu Association for Science and Technology,China。
文摘Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.
