Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City usin...Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City using Transformation Coefficient(TC):first,in the period 1999-2000,the land use structure coefficient(θ1) declined by 79.55%,but the overall evolution trend is gentle;second,the transformation coefficient of industrial structure(θ2) tended to decline ceaselessly on the whole,a decrease of 36.09%(overall,the transformation coefficient of industrial structure is slightly greater than the land use structure coefficient);third,the inter-annual variation of the two experienced ups and downs(in the period 1999-2007,the inter-annual variation was great and in the period 2008-2010,the inter-annual variation tended to be gentle).On the basis of autocorrelation and co-integration model,we draw the following conclusions through analysis:first,the land use structure in Xining City plays a role in promoting industrial structure transformation;second,there is a long-term equilibrium relationship between the two.Finally,relevant policy recommendations are put forward for the industrial development in Xining City.展开更多
Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,Chi...Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.展开更多
This study takes Kunming City, Yunnan Province, China as the research area, to provide reference basis for revealing the change law of land use structure and energy consumption and carbon emissions in Kunming, optimiz...This study takes Kunming City, Yunnan Province, China as the research area, to provide reference basis for revealing the change law of land use structure and energy consumption and carbon emissions in Kunming, optimizing land use structure and realizing the development of low-carbon city. Based on the data of land use structure and energy consumption in Kunming from 1997 to 2017, based on the estimation of total energy consumption carbon emissions, carbon intensity and per capita carbon emissions, the correlation between land use structure and energy consumption carbon emissions in Kunming has been calculated and analyzed in the past 20 years. Results: 1) The total amount of carbon emissions in Kunming has increased significantly in the past 20 years. It increased from 34.46 × 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> t to 95.09 × 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> t, an increase of about 2.8 times. 2) The types of land use with the highest correlation between land use structure and total carbon emissions of energy consumption, carbon emission intensity and per capita carbon emissions are urban and village and industrial and mining land (0.8258), cultivated land (0.8733) and garden land (0.7971) respectively. 3) The correlation between construction land and total carbon emissions is greater than that of agricultural land. Conclusion: There is a close correlation between land use structure and carbon emissions from energy consumption in Kunming.展开更多
Urbanization is one of the driving forces for the land use change in type and structure, and its prominent effect is to convert rural land to urban land. This paper takes Shan-dong Province as an example to analyze th...Urbanization is one of the driving forces for the land use change in type and structure, and its prominent effect is to convert rural land to urban land. This paper takes Shan-dong Province as an example to analyze the current situation of the mutual conversion between the urban and rural areas from the aspects of the structure of land use, the decreasing tendency of the cultivated land, the changes of land use in urban and rural residential areas. It points out that cultivated land is converted to residential area land, industrial and/or mining area land. The relationship between the urban area land and the cultivated land is more direct; meanwhile, the changes of rural residential area lag behind obviously. The decrease of the cultivated land and the decline of soil quality will be the two difficult problems in the process of urbanization.展开更多
Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultiva...Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008-2020 under three scenarios, the baseline scenario, low TFP (total factor productivity) scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined signifi- cantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.展开更多
The ecological environment quality is an important constraint and an optimization objective for land resource allocation.Integrating ecological service value(ESV)accounting and ecological security pattern(ESP)delineat...The ecological environment quality is an important constraint and an optimization objective for land resource allocation.Integrating ecological service value(ESV)accounting and ecological security pattern(ESP)delineation,and combining with the land use structure of 2004/2010/2016 in Ezhou City,this research laid out the urban ESP based on ESV with Net Primary Productivity(NPP),and made it as the main influence factor to simulate land use structure in 2022.The results indicated that:1)The water body has the biggest contribution to ESV,while the construction land has the minimum;2)91 ecological corridors are extracted,of which 28 were important ecological corridors;there were 36 ecological nodes extracted,including 17 important nodes;3)According to ESV,Ezhou City was divided into four security zones.The area of ecological restoration zone was the largest,and human activity core zone area was the smallest;4)In the no ESP protection scenarios and ESP protection scenarios separately,the net increase area of construction land is from 868.5 hm^(2) to 52.74 hm^(2) in the ecological core protection area;the construction land in the human activity core area has been increased by 2342.31 hm^(2) in protected scene,766.23 hm^(2) more than that of the unprotected scene.The results show that the division of security zones promoted the relocation of construction land from ecological protection core zone to human activity core zone,which can protect the ecological environment effectively,and the ESP-based simulation can provide the decision-making reference to coordinate the relationship of regional land resource allocation and the ecological environment protection.展开更多
Since the concept of "fishing down marine food webs" was first proposed in 1998, mean trophic level of fisheries landings(MTL) has become one of the most widely used indicators to assess the impacts of fishing on ...Since the concept of "fishing down marine food webs" was first proposed in 1998, mean trophic level of fisheries landings(MTL) has become one of the most widely used indicators to assess the impacts of fishing on the integrity of marine ecosystem and guide the policy development by many management agencies. Recent studies suggest that understanding underlying causes for changes in MTL is vital for an appropriate use of MTL as an indicator of fishery sustainability. Based on the landing data compiled by Food and Agriculture Organization(FAO) and trophic information of relevant species in Fishbase, we evaluated MTL trends in 14 FAO fishing areas and analyzed catches of upper and lower trophic level groups under different trends of MTL and found that both the cases of a recovered MTL trend and a generally increasing MTL trend could be accompanied by decreasing catches of lower trophic level species. Further, community structure and exploitation history should be considered in using MTL after excluding species with trophic levels lower than 3.25 to distinguish "fishingthrough" from "fishing-down". We conclude that MTL used as an indicator to measure fishery sustainability can benefit from a full consideration of both upper and lower trophic level species and masking effects of community structure and exploitation history.展开更多
This paper studies the mechanism of grassland ecosystem's soil and water conservation function on the basis of two years experiment and inspection in Jianou mountain grassland ecosystem experiment station, Fujian ...This paper studies the mechanism of grassland ecosystem's soil and water conservation function on the basis of two years experiment and inspection in Jianou mountain grassland ecosystem experiment station, Fujian province. After anaIysis on the data of soil erosion and runoff coefficient, relations between eroded soil, runoff and slope gradient. we establish soil and water conservation benefit models. According to the mode1s, experiment and inspection results, some proposals have been made to decrease the area of soil erosion in Fujian mountainous areas, e. g., optimizing land use structure in mountainous areas, taking suitable measures for local condition, closing hills for grassland development, accelerating restoration and raising quality of mountain grassland ecosystem, strengthening scientific and technological input, breeding the grass species that are suitable to local physical geographic condition.展开更多
The aim of this paper is to sift through examples of outstanding contributions made by Chinese human geography in terms of social applications and explain the basic concepts and theoretical methods explored by human g...The aim of this paper is to sift through examples of outstanding contributions made by Chinese human geography in terms of social applications and explain the basic concepts and theoretical methods explored by human geography that are behind the applications of results with major social influence, so as to be able to summarize the main school that represents developments in contemporary Chinese human geography. Chinese human geography upholds the subject's designation as being integrated and interdisciplinary. Research focuses on interactions between the natural and human spheres of the Earth's surface, and it is guided by the understanding and effects of the processes of regional sustainable development at different spatial scales. Chinese human geography has innovatively established the following development paradigm: "To be guided by application requirements, refine key issues of the discipline in the course of solving major issues of human geography in national and regional development, and by solving those key issues, to enhance its ability to provide scientific and technological support to serve national and local needs while promoting its own development." Results from early Chinese human geography studies on land use and agricultural zoning, recent research results on point-axis system models and T-shaped national spatial development patterns, and current research results on territorial function theory and major function oriented zones have all continued and strengthened the mainstream school of Chinese human geography and have avoided the global tendency for human geography to become rapidly human-oriented, while results have been applied at the highest level of decision-making management. Chinese human geography can provide lessons for developing countries and may play a leading role in the future development of global human geography.展开更多
Airworthiness regulations require that the transport airplane should be proved to ensure the survivability of the ditching for the passengers. The planned ditching of a transport airplane on the calm water is numerica...Airworthiness regulations require that the transport airplane should be proved to ensure the survivability of the ditching for the passengers. The planned ditching of a transport airplane on the calm water is numerically simulated. The effect of pitch angle on the impact characteristics is especially investigated by a subscaled model. The Reynolds-averaged Navier-Stokes (RANS) equations of unsteady compressible flow are solved and the realizable j-e equations are employed to model the turbulence. The transformation of the air-water interface is tracked by volume of fluid (VOF) model. The motion of the rigid body is modeled by dynamic mesh method. The initial ditching stage of the transport airplane is analyzed in detail. The numerical results show that as the pitching angle increases, the maximal normal force decreases and the pitching motion becomes much gentler. The aft fuselage would be sucked down by the water and lead to pitching up, whereas the low horizontal tail prevents this trend. Consequently, the transport aircraft with low horizontal tail should ditch on the water at an angle between 10 and 12 as a recommendation.展开更多
基金Supported by National Natural Science Foundation Project(41101098)Youth Project of Xianning University(KY10044,KY10043)
文摘Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City using Transformation Coefficient(TC):first,in the period 1999-2000,the land use structure coefficient(θ1) declined by 79.55%,but the overall evolution trend is gentle;second,the transformation coefficient of industrial structure(θ2) tended to decline ceaselessly on the whole,a decrease of 36.09%(overall,the transformation coefficient of industrial structure is slightly greater than the land use structure coefficient);third,the inter-annual variation of the two experienced ups and downs(in the period 1999-2007,the inter-annual variation was great and in the period 2008-2010,the inter-annual variation tended to be gentle).On the basis of autocorrelation and co-integration model,we draw the following conclusions through analysis:first,the land use structure in Xining City plays a role in promoting industrial structure transformation;second,there is a long-term equilibrium relationship between the two.Finally,relevant policy recommendations are put forward for the industrial development in Xining City.
文摘Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.
文摘This study takes Kunming City, Yunnan Province, China as the research area, to provide reference basis for revealing the change law of land use structure and energy consumption and carbon emissions in Kunming, optimizing land use structure and realizing the development of low-carbon city. Based on the data of land use structure and energy consumption in Kunming from 1997 to 2017, based on the estimation of total energy consumption carbon emissions, carbon intensity and per capita carbon emissions, the correlation between land use structure and energy consumption carbon emissions in Kunming has been calculated and analyzed in the past 20 years. Results: 1) The total amount of carbon emissions in Kunming has increased significantly in the past 20 years. It increased from 34.46 × 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> t to 95.09 × 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> t, an increase of about 2.8 times. 2) The types of land use with the highest correlation between land use structure and total carbon emissions of energy consumption, carbon emission intensity and per capita carbon emissions are urban and village and industrial and mining land (0.8258), cultivated land (0.8733) and garden land (0.7971) respectively. 3) The correlation between construction land and total carbon emissions is greater than that of agricultural land. Conclusion: There is a close correlation between land use structure and carbon emissions from energy consumption in Kunming.
文摘Urbanization is one of the driving forces for the land use change in type and structure, and its prominent effect is to convert rural land to urban land. This paper takes Shan-dong Province as an example to analyze the current situation of the mutual conversion between the urban and rural areas from the aspects of the structure of land use, the decreasing tendency of the cultivated land, the changes of land use in urban and rural residential areas. It points out that cultivated land is converted to residential area land, industrial and/or mining area land. The relationship between the urban area land and the cultivated land is more direct; meanwhile, the changes of rural residential area lag behind obviously. The decrease of the cultivated land and the decline of soil quality will be the two difficult problems in the process of urbanization.
文摘Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008-2020 under three scenarios, the baseline scenario, low TFP (total factor productivity) scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined signifi- cantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.
基金supported by the National Natural Science Foundation of China(Grant No.41871172).
文摘The ecological environment quality is an important constraint and an optimization objective for land resource allocation.Integrating ecological service value(ESV)accounting and ecological security pattern(ESP)delineation,and combining with the land use structure of 2004/2010/2016 in Ezhou City,this research laid out the urban ESP based on ESV with Net Primary Productivity(NPP),and made it as the main influence factor to simulate land use structure in 2022.The results indicated that:1)The water body has the biggest contribution to ESV,while the construction land has the minimum;2)91 ecological corridors are extracted,of which 28 were important ecological corridors;there were 36 ecological nodes extracted,including 17 important nodes;3)According to ESV,Ezhou City was divided into four security zones.The area of ecological restoration zone was the largest,and human activity core zone area was the smallest;4)In the no ESP protection scenarios and ESP protection scenarios separately,the net increase area of construction land is from 868.5 hm^(2) to 52.74 hm^(2) in the ecological core protection area;the construction land in the human activity core area has been increased by 2342.31 hm^(2) in protected scene,766.23 hm^(2) more than that of the unprotected scene.The results show that the division of security zones promoted the relocation of construction land from ecological protection core zone to human activity core zone,which can protect the ecological environment effectively,and the ESP-based simulation can provide the decision-making reference to coordinate the relationship of regional land resource allocation and the ecological environment protection.
基金The National Natural Science Foundation of China under contract Nos NSFC41306127 and NSFC41276156the Funding Program for Outstanding Dissertations in Shanghai Ocean University+1 种基金the Funding Scheme for Training Young Teachers in Shanghai Colleges and Shanghai Leading Academic Discipline Project(Fisheries Discipline)the involvement of Y.Chen was supported by SHOU International Center for Marine Studies and Shanghai 1000 Talent Program
文摘Since the concept of "fishing down marine food webs" was first proposed in 1998, mean trophic level of fisheries landings(MTL) has become one of the most widely used indicators to assess the impacts of fishing on the integrity of marine ecosystem and guide the policy development by many management agencies. Recent studies suggest that understanding underlying causes for changes in MTL is vital for an appropriate use of MTL as an indicator of fishery sustainability. Based on the landing data compiled by Food and Agriculture Organization(FAO) and trophic information of relevant species in Fishbase, we evaluated MTL trends in 14 FAO fishing areas and analyzed catches of upper and lower trophic level groups under different trends of MTL and found that both the cases of a recovered MTL trend and a generally increasing MTL trend could be accompanied by decreasing catches of lower trophic level species. Further, community structure and exploitation history should be considered in using MTL after excluding species with trophic levels lower than 3.25 to distinguish "fishingthrough" from "fishing-down". We conclude that MTL used as an indicator to measure fishery sustainability can benefit from a full consideration of both upper and lower trophic level species and masking effects of community structure and exploitation history.
基金The project is supported by Henan Province Natural Science Foundation (004070900)HenanProvince Scientific an
文摘This paper studies the mechanism of grassland ecosystem's soil and water conservation function on the basis of two years experiment and inspection in Jianou mountain grassland ecosystem experiment station, Fujian province. After anaIysis on the data of soil erosion and runoff coefficient, relations between eroded soil, runoff and slope gradient. we establish soil and water conservation benefit models. According to the mode1s, experiment and inspection results, some proposals have been made to decrease the area of soil erosion in Fujian mountainous areas, e. g., optimizing land use structure in mountainous areas, taking suitable measures for local condition, closing hills for grassland development, accelerating restoration and raising quality of mountain grassland ecosystem, strengthening scientific and technological input, breeding the grass species that are suitable to local physical geographic condition.
基金Key Project of National Natural Science Foundation of China,No.40830741 National Key Technology R&D Program,No.2008BAH31B01
文摘The aim of this paper is to sift through examples of outstanding contributions made by Chinese human geography in terms of social applications and explain the basic concepts and theoretical methods explored by human geography that are behind the applications of results with major social influence, so as to be able to summarize the main school that represents developments in contemporary Chinese human geography. Chinese human geography upholds the subject's designation as being integrated and interdisciplinary. Research focuses on interactions between the natural and human spheres of the Earth's surface, and it is guided by the understanding and effects of the processes of regional sustainable development at different spatial scales. Chinese human geography has innovatively established the following development paradigm: "To be guided by application requirements, refine key issues of the discipline in the course of solving major issues of human geography in national and regional development, and by solving those key issues, to enhance its ability to provide scientific and technological support to serve national and local needs while promoting its own development." Results from early Chinese human geography studies on land use and agricultural zoning, recent research results on point-axis system models and T-shaped national spatial development patterns, and current research results on territorial function theory and major function oriented zones have all continued and strengthened the mainstream school of Chinese human geography and have avoided the global tendency for human geography to become rapidly human-oriented, while results have been applied at the highest level of decision-making management. Chinese human geography can provide lessons for developing countries and may play a leading role in the future development of global human geography.
基金co-supported by Aeronautical Science Foundation of China (No.20102351023)Research Fund for the Doctoral Program of Higher Education of China (No. 20091102120021)
文摘Airworthiness regulations require that the transport airplane should be proved to ensure the survivability of the ditching for the passengers. The planned ditching of a transport airplane on the calm water is numerically simulated. The effect of pitch angle on the impact characteristics is especially investigated by a subscaled model. The Reynolds-averaged Navier-Stokes (RANS) equations of unsteady compressible flow are solved and the realizable j-e equations are employed to model the turbulence. The transformation of the air-water interface is tracked by volume of fluid (VOF) model. The motion of the rigid body is modeled by dynamic mesh method. The initial ditching stage of the transport airplane is analyzed in detail. The numerical results show that as the pitching angle increases, the maximal normal force decreases and the pitching motion becomes much gentler. The aft fuselage would be sucked down by the water and lead to pitching up, whereas the low horizontal tail prevents this trend. Consequently, the transport aircraft with low horizontal tail should ditch on the water at an angle between 10 and 12 as a recommendation.