Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resista...Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance.展开更多
To study the effect of the particle size of industrial alumina powder on the properties of active alumina micropowder(α-Al_(2)O_(3) micropowder),the fine powders with the median diameter of 50,30,10,and 5 pm,respecti...To study the effect of the particle size of industrial alumina powder on the properties of active alumina micropowder(α-Al_(2)O_(3) micropowder),the fine powders with the median diameter of 50,30,10,and 5 pm,respectively,were obtained by grinding industrial alumina powder(the median diameter of 80 pm),and the active alumina micropowders were prepared by firing the industrial alumina powders before and after grinding at 1320℃ for 5 h.The effect of the particle size of the industrial alumina powder on the microstructure and properties of the active alumina micropowder was researched.The results indicate that the initial particle size of the industrial alumina powder has a great influence on the grain morphology of the active alumina micropowder;when the median diameter is larger than 30 pm,the α-Al_(2)O_(3) grains show wormlike aggregates state after calcination and when it is around or less than 10 pm,the α-Al_(2)O_(3) are round,spherical and well dispersed grains with the particle size of 0.3-1.0 pm.With the initial particle size of the industrial alumina powder decreasing,the α-Al_(2)O_(3) phase transition rate increases and the true density gradually increases;moreover,the α-Al_(2)O_(3) powder shows better dispersity and flowability.展开更多
The thesis analyzes the role of small-and-medium-sized enterprises of county in promoting county economy:the small-and-medium-sized enterprises of county become the material basis of developing production and boosting...The thesis analyzes the role of small-and-medium-sized enterprises of county in promoting county economy:the small-and-medium-sized enterprises of county become the material basis of developing production and boosting county economy;the small-and-medium-sized enterprises of county become the main channel of increasing farmers' job opportunities and realizing affluent life;the development of the small-and-medium-sized enterprises of county become the propeller of development of urbanization and county economy;the development of the small-and-medium-sized enterprises of county creates excellent conditions for the construction of modern agriculture.The thesis indicates that the low level of county industrialization is the principal factor impeding the county economy of Shaanxi Province and it also analyzes the opportunities and challenges when quickening the development of county industry.The countermeasures of developing small-and-medium-sized enterprises are put forward as follows:raise the awareness and determine the concept of using industry to make county powerful;build scientific planning and outline of county enterprise development to propel the innovation of developing and operating system of county enterprise;create beneficial conditions and reinforce the degree of county enterprise support entrepreneurship;take the park construction as vehicle and reinforce the degree of attracting investments from overseas;take the autonomous innovation as the impetus and develop the recycling economy;improve and optimize the service environment so as to create an excellent investment environment for enterprise.展开更多
This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of c...This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity.展开更多
基金The authors gratefully acknowledge the funding of the project by SINOPEC(No.118001-6).
文摘Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance.
文摘To study the effect of the particle size of industrial alumina powder on the properties of active alumina micropowder(α-Al_(2)O_(3) micropowder),the fine powders with the median diameter of 50,30,10,and 5 pm,respectively,were obtained by grinding industrial alumina powder(the median diameter of 80 pm),and the active alumina micropowders were prepared by firing the industrial alumina powders before and after grinding at 1320℃ for 5 h.The effect of the particle size of the industrial alumina powder on the microstructure and properties of the active alumina micropowder was researched.The results indicate that the initial particle size of the industrial alumina powder has a great influence on the grain morphology of the active alumina micropowder;when the median diameter is larger than 30 pm,the α-Al_(2)O_(3) grains show wormlike aggregates state after calcination and when it is around or less than 10 pm,the α-Al_(2)O_(3) are round,spherical and well dispersed grains with the particle size of 0.3-1.0 pm.With the initial particle size of the industrial alumina powder decreasing,the α-Al_(2)O_(3) phase transition rate increases and the true density gradually increases;moreover,the α-Al_(2)O_(3) powder shows better dispersity and flowability.
基金Supported by Specific Scientific Research Program of Education Department of Shaanxi Province in 2010(2010JK348)Specific Scientific Research Program of Xianyang Normal University(09XSYK243)
文摘The thesis analyzes the role of small-and-medium-sized enterprises of county in promoting county economy:the small-and-medium-sized enterprises of county become the material basis of developing production and boosting county economy;the small-and-medium-sized enterprises of county become the main channel of increasing farmers' job opportunities and realizing affluent life;the development of the small-and-medium-sized enterprises of county become the propeller of development of urbanization and county economy;the development of the small-and-medium-sized enterprises of county creates excellent conditions for the construction of modern agriculture.The thesis indicates that the low level of county industrialization is the principal factor impeding the county economy of Shaanxi Province and it also analyzes the opportunities and challenges when quickening the development of county industry.The countermeasures of developing small-and-medium-sized enterprises are put forward as follows:raise the awareness and determine the concept of using industry to make county powerful;build scientific planning and outline of county enterprise development to propel the innovation of developing and operating system of county enterprise;create beneficial conditions and reinforce the degree of county enterprise support entrepreneurship;take the park construction as vehicle and reinforce the degree of attracting investments from overseas;take the autonomous innovation as the impetus and develop the recycling economy;improve and optimize the service environment so as to create an excellent investment environment for enterprise.
文摘This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity.
