The primary object of this paper is to examine the spatial-temporal pattern evolution of manufacturing geographical agglomeration of the old industrial base.Industrial spatial agglomeration index and concentration rat...The primary object of this paper is to examine the spatial-temporal pattern evolution of manufacturing geographical agglomeration of the old industrial base.Industrial spatial agglomeration index and concentration ratio are used in this paper.Multiple linear regression models are also applied to try to explore the internal driving mechanisms on manufacturing geographical agglomeration.The results show that:1) the manufacturing agglomeration degree of Jilin Province is increasing gradually.The spatial polarization structure is visible;and the central region is the agglomeration area,in addition,the manufacturing industries of Changchun Proper present a trend of dispersion;2) the structure of manufacturing industries has changed,and the concentration ratio of labor-intensive manufacturing industry is declining,while the proportions of technology-intensive and capital-intensive manufacturing industry are relatively rising;3) marketing level,location accessibility,labor resources,capital,science and technology innovation capability,scale economy and the level of globalization affect manufacturing agglomeration with different degree.There are significant differences of the effects about employment,technology,the quality of residents and the export-oriented market on the industrial concentration ratio;4) in the future,the impact of policy and institution,export-oriented market and quality of resident on manufacturing geographical agglomeration pattern will be more profound.展开更多
The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when wat...The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when water-binder ratio is lower than 0.40, the cement-based material with limestone powder has insignificant change in appearance after being soaked in 10% magnesium sulfate solution at low temperature for 120 d, and has significant change in appearance after being soaked at the age of 200 d. Expansion damage and exfoliation occur on the surface of concrete test cube at different levels. When limestone powder accounts for about 28 percent of cementitious material, with the decrease of water-binder ratio, the compressive strength loss has gradually decreased after the material is soaked in the magnesium sulfate solution at low temperature at the age of 200 d. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200 d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.展开更多
The forest litter is an essential reservoir of nutrients in forests, supplying a large part of absorbable base cations(BC) to topsoil, and facilitating plant growth within litter-soil system. To characterize elevation...The forest litter is an essential reservoir of nutrients in forests, supplying a large part of absorbable base cations(BC) to topsoil, and facilitating plant growth within litter-soil system. To characterize elevational patterns of base cation concentrations in the forest litter and topsoil, and explore the effects of climate and tree species, we measured microclimate and collected the forest litter and topsoil(0-10 cm) samples across an elevational range of more than 2000 m(1243 ～ 3316 m a.s.l.),and analyzed the concentrations of BC in laboratory. Results showed that: 1) litter Ca concentration displayed a hump-shaped pattern along the elevational gradients, but litter K and Mg showed saddle-shaped patterns. Soil Ca concentration increased with elevation, while soil K and Mg had no significant changes. 2) Ca concentration in the forest litter under aspen(Populus davidiana) was significantly higher than that in all other species, but in topsoil, Ca concentration was higher under coniferous larch and fir(Larix chinensis and Abies fargesii). Litter K and Mg concentrations was higher under coniferous larch and fir, whereas there were nosignificant differences among tree species in the concentrations of K and Mg in topsoil. 3) Climatic factors including mean annual temperature(MAT), growing season precipitation(GSP) and non-growing season precipitation(NGSP) determined BC concentrations in the forest litter and topsoil. Soil C/N and C/P also influenced BC cycling between litter and soil. Observation along elevations within different tree species implies that above-ground tree species can redistribute below-ground cations, and this process is profoundly impacted by climate. Litter and soil Ca, K and Mg with different responses to environmental variables depend on their soluble capacity and mobile ability.展开更多
[Objective] The aim was to research effects of N fertilizer reduction and application of N fertilizer （as base fertilizer） on rapeseed yield and N absorption. [Method] Based on Ganyouza No.5, the ratio of N, P2O5 an...[Objective] The aim was to research effects of N fertilizer reduction and application of N fertilizer （as base fertilizer） on rapeseed yield and N absorption. [Method] Based on Ganyouza No.5, the ratio of N, P2O5 andK2O was set at 1：0.5：0.5; N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2; 100%, 80% and 60% of N fertilizers were applied as base fertilizers in the test respectively. In general, field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption. [Resalt] When applied N fertilizer as base fertilizer was the same, plant height, stem diameter, length of major inflorescence, number of effective branch, pod number per plant, seed number per pod, and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer. Rapeseed yield and profits in group with preferred N quantity were signifi- cantly higher than those in group with reduced N fertilizer in field with moderate fertili- ty. In fields with higher fertility, however, the two factors were just a little higher. In group with reduced N fertilizer, use efficiency of N fertilizer, N uptake efficiency, par- tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer. Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz- er in field with moderate fertility and was significantly lower in field with high yield. With amounts of N, P and K fertilizers fixed, economic characters, yield constitution, yield, profits and N absorption in group, where 60% of N fertilizers were applied as base fertilizer, were significantly higher than those in groups with 80% or 100% of base fertilizer （N fertilizers）. These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer. On the other hand, it is effective to improve rapeseed yield.＇to reduce N fertilizer to 150 kg/hm2, and application of 60%. of N fertilizers as base fertilizer is still proved optimal at present. [Conclusion] The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41371135)Science and Technology Guide Plan Soft Science Project of Jilin Province(No.20120635)
文摘The primary object of this paper is to examine the spatial-temporal pattern evolution of manufacturing geographical agglomeration of the old industrial base.Industrial spatial agglomeration index and concentration ratio are used in this paper.Multiple linear regression models are also applied to try to explore the internal driving mechanisms on manufacturing geographical agglomeration.The results show that:1) the manufacturing agglomeration degree of Jilin Province is increasing gradually.The spatial polarization structure is visible;and the central region is the agglomeration area,in addition,the manufacturing industries of Changchun Proper present a trend of dispersion;2) the structure of manufacturing industries has changed,and the concentration ratio of labor-intensive manufacturing industry is declining,while the proportions of technology-intensive and capital-intensive manufacturing industry are relatively rising;3) marketing level,location accessibility,labor resources,capital,science and technology innovation capability,scale economy and the level of globalization affect manufacturing agglomeration with different degree.There are significant differences of the effects about employment,technology,the quality of residents and the export-oriented market on the industrial concentration ratio;4) in the future,the impact of policy and institution,export-oriented market and quality of resident on manufacturing geographical agglomeration pattern will be more profound.
文摘The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when water-binder ratio is lower than 0.40, the cement-based material with limestone powder has insignificant change in appearance after being soaked in 10% magnesium sulfate solution at low temperature for 120 d, and has significant change in appearance after being soaked at the age of 200 d. Expansion damage and exfoliation occur on the surface of concrete test cube at different levels. When limestone powder accounts for about 28 percent of cementitious material, with the decrease of water-binder ratio, the compressive strength loss has gradually decreased after the material is soaked in the magnesium sulfate solution at low temperature at the age of 200 d. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200 d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.
基金supported by the National Natural Science Foundation of China (Grants No. 41771051 and No. 41630750)the National Key Basic Research Special Foundation of China (Grants No. 2011FY110300)
文摘The forest litter is an essential reservoir of nutrients in forests, supplying a large part of absorbable base cations(BC) to topsoil, and facilitating plant growth within litter-soil system. To characterize elevational patterns of base cation concentrations in the forest litter and topsoil, and explore the effects of climate and tree species, we measured microclimate and collected the forest litter and topsoil(0-10 cm) samples across an elevational range of more than 2000 m(1243 ～ 3316 m a.s.l.),and analyzed the concentrations of BC in laboratory. Results showed that: 1) litter Ca concentration displayed a hump-shaped pattern along the elevational gradients, but litter K and Mg showed saddle-shaped patterns. Soil Ca concentration increased with elevation, while soil K and Mg had no significant changes. 2) Ca concentration in the forest litter under aspen(Populus davidiana) was significantly higher than that in all other species, but in topsoil, Ca concentration was higher under coniferous larch and fir(Larix chinensis and Abies fargesii). Litter K and Mg concentrations was higher under coniferous larch and fir, whereas there were nosignificant differences among tree species in the concentrations of K and Mg in topsoil. 3) Climatic factors including mean annual temperature(MAT), growing season precipitation(GSP) and non-growing season precipitation(NGSP) determined BC concentrations in the forest litter and topsoil. Soil C/N and C/P also influenced BC cycling between litter and soil. Observation along elevations within different tree species implies that above-ground tree species can redistribute below-ground cations, and this process is profoundly impacted by climate. Litter and soil Ca, K and Mg with different responses to environmental variables depend on their soluble capacity and mobile ability.
基金Supported by China Modern Agriculture Research System (CARS-13)Jiangxi Technological Innovation Team (20115BCB29020)Innovation Funds of Jiangxi Academy of Agricultural Sciences (2011CJJ012)~~
文摘[Objective] The aim was to research effects of N fertilizer reduction and application of N fertilizer （as base fertilizer） on rapeseed yield and N absorption. [Method] Based on Ganyouza No.5, the ratio of N, P2O5 andK2O was set at 1：0.5：0.5; N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2; 100%, 80% and 60% of N fertilizers were applied as base fertilizers in the test respectively. In general, field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption. [Resalt] When applied N fertilizer as base fertilizer was the same, plant height, stem diameter, length of major inflorescence, number of effective branch, pod number per plant, seed number per pod, and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer. Rapeseed yield and profits in group with preferred N quantity were signifi- cantly higher than those in group with reduced N fertilizer in field with moderate fertili- ty. In fields with higher fertility, however, the two factors were just a little higher. In group with reduced N fertilizer, use efficiency of N fertilizer, N uptake efficiency, par- tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer. Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz- er in field with moderate fertility and was significantly lower in field with high yield. With amounts of N, P and K fertilizers fixed, economic characters, yield constitution, yield, profits and N absorption in group, where 60% of N fertilizers were applied as base fertilizer, were significantly higher than those in groups with 80% or 100% of base fertilizer （N fertilizers）. These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer. On the other hand, it is effective to improve rapeseed yield.＇to reduce N fertilizer to 150 kg/hm2, and application of 60%. of N fertilizers as base fertilizer is still proved optimal at present. [Conclusion] The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.
