Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation metho...Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.展开更多
Characteristics of road landscaping were analyzed,as a kind of "linear" landscaping,it could be classified into urban street landscaping,urban ring road and expressway landscaping.Differences between road la...Characteristics of road landscaping were analyzed,as a kind of "linear" landscaping,it could be classified into urban street landscaping,urban ring road and expressway landscaping.Differences between road landscaping projects and other garden landscaping projects or construction projects were analyzed.Landscaping project for the South 3rd Ring Road of Xi'an City(in Yanta District)was taken for an example to summarize construction experience,discuss present conditions and features of garden landscaping supervision in China.The artistic and physiological properties of garden landscaping,as well as the supervision during maintenance period were stressed,but it was also pointed out that garden landscaping supervision in China was actually not given sufficient attention.On this basis,key points in the supervision of road landscaping project were proposed:understanding design ideas,selection of landscape plants,quality control of concealed works,prevention and control of diseases and insects,construction safety management and overall image;only by effectively implementing these key points,a high-quality road landscaping project could be realized to improve the image of a city and beautify its environment.展开更多
[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns (corn field, cherry tree land, wood land) ...[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns (corn field, cherry tree land, wood land) were selected from Hongta District, Yuxi City, and under these three patterns, soil microbial quantity and activity were studied. [Result] Under the three land use patterns, soil microorganisms were domi- nated by bacteria; soil microbial quantity ranked as wood land's〉cheery tree land's〉 corn field's; and total microbial activity, catalase activity and urease activity all ranked as cherry tree land's〉wood land's〉corn field's. [Conclusion] Soil microbial activity and functions are related to farmland management measures, as well as land use pattern and soil nutrients.展开更多
This study aimed to provide theoretical basis for an optimized land use of Xigu District in Lanzhou City,Gansu Province.With the support of GIS platform,structural characteristics of 11 land use types in Xigu District...This study aimed to provide theoretical basis for an optimized land use of Xigu District in Lanzhou City,Gansu Province.With the support of GIS platform,structural characteristics of 11 land use types in Xigu District were analyzed by utilizing fragmentation degree,shape index,fractal dimension,diversity and such landscape pattern indices.展开更多
Mountains and waters serve as important elements for urban spatial mor-phology, structure and eco-environment. Since scientist Qian Xuesen proposed the concept of landscape city, it has been an effective way for urban...Mountains and waters serve as important elements for urban spatial mor-phology, structure and eco-environment. Since scientist Qian Xuesen proposed the concept of landscape city, it has been an effective way for urban development in case of thousand-city in the same appearance. In the study, we analyzed the con-cept, connotation and approaches and proposed the ways to landscape city.展开更多
Edge effect theory is introduced in this study to define the concepts and connotations of marginal zone and edge effect in the planning of rural tourism,and it is proposed that edge effect should be paid more attentio...Edge effect theory is introduced in this study to define the concepts and connotations of marginal zone and edge effect in the planning of rural tourism,and it is proposed that edge effect should be paid more attention.By taking the rural tourism planning of Lintong District for an example,the development and realization approaches of edge effect in rural tourism planning are further analyzed from both overall and detailed planning.展开更多
Under the background of new urbanization, rural buildings' energy efficiency retrofit is an essential part of the overall work of the building energy conservation. Therefore, taking rural buildings in hot-summer and ...Under the background of new urbanization, rural buildings' energy efficiency retrofit is an essential part of the overall work of the building energy conservation. Therefore, taking rural buildings in hot-summer and cold-winter zone as the research object, we carried out field investigation by combining geographical climate charactedstics with social-economic conditions and analyzed the energy consumption and energy conservation of rural buildings in hot-summer and cold-winter zone. On the basis of the investigation and analysis, this paper pointed out the questions with its energy efficiency retrofit and proposed the energy-saving strategy which was suitable for rural buildings in hot-summer and cold-winter zone based on people's livelihood and development.展开更多
This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out e...This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out earthquake disaster reduction planning for districts or countries in the northwest. With Hongsibao District in Wuzhong City, Ningxia Province as an example, this article analyzed in detail the present situation and the special problems of earthquake disaster reduction planning in Northwest China. The relevant solving measures were put forward in order to offer a reference for the scientific establishment and effective implementation of earth- quake disaster reduction planning in Northwest China. The foundation of earthquake disaster reduction in the Hongsibao District is still very weak, there is a single earthquake monitoring means, the emergency rescue system is not complete, the working mechanism is not perfect, and the lack of funding for the work of earthquake disaster reduction.展开更多
With the case study of Honggutan New District as reference,this paper elaborated the significance of urban green space;the ecological function and cultural function of green landscape which were respectively manifeste...With the case study of Honggutan New District as reference,this paper elaborated the significance of urban green space;the ecological function and cultural function of green landscape which were respectively manifested in the aspect of living and production and in the aspect of accumulation,sedimentation and renovation mark of urban history development.It also explained the composition of wetland region,the situation that there existed quite a lot of wetland,wetland flower species and landscape types.And the existing problems in the construction of Honggutan green landscape were analyzed,which were the fact that the spatial distribution of plants was unreasonable and impracticable;that the function of green space hadn't been fully displayed,lack of participation;that the landscaping plant was monotonous,short of cultural deposits.On the basis of the design theory of green landscape and the living examples of some developed cities,the regionality of urban green landscape was studied;the design principles of elegance,functionality,people-orientation,regional culture's continuity and ecology were put forward,aiming at providing reference for using different factors of practical measures to achieve landscape eco-design with geographical features.展开更多
ABSTRACT: At the study area of Xigu District in Lanzhou City, using RS & GIS as tools we apply Diversity, Dominance, Fragmentation , Isolation and so on to study the quantitative, fractal and spatial characters of...ABSTRACT: At the study area of Xigu District in Lanzhou City, using RS & GIS as tools we apply Diversity, Dominance, Fragmentation , Isolation and so on to study the quantitative, fractal and spatial characters of landscapes’ structures in the four sub-regions divided by the morphological features. Using the Fractal Theory to establish the fractal structure models, we analyze the complexity and stability of various landscapes’ distribution with fractal dimension value. The spatial distribution characteristics of landscape mosaic structure are also expounded. At the end of the paper we discuss the relevant problems on the main factors which control and effect on the spatial pattern of landscapes as well as on landscape optimization and management.展开更多
This paper compares monthly and seasonal rain rates derived from the Version 5 (V5) and Version 6 (V6) TRMM Precipitation Radar (TPR, TSDIS reference 2A25), TRMM Microwave Imager (TMI, 2A12), TRMM Combined Ins...This paper compares monthly and seasonal rain rates derived from the Version 5 (V5) and Version 6 (V6) TRMM Precipitation Radar (TPR, TSDIS reference 2A25), TRMM Microwave Imager (TMI, 2A12), TRMM Combined Instrument (TCI, 2B31), TRMM calibrated IR rain estimates (3B42) and TRMM merged gauge and satellite analysis (3B43) algorithms over New Mexico (NM) with rain gauge analyses provided by the New Mexico water districts (WD). The average rain rates over the NM region for 1998- 2002 are 0.91 mm d^-1 for WD and 0.75, 1.38, 1.49, 1.27, and 1.07 mm d^-1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d^-1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with WD rain rates and the daily TRMM mission index (TPR and TMI) suggests that the low bias of V5 3B43 for the wet months (summer to early fall) may be due to the non-inclusion of some rain events in the operational gauge analyses that. are used in the production of V5 3B43. Correlation analyses show that the WD rain rates vary in phase, with higher correlation between neighboring WDs. High temporal correlations (〉0.8) exist between WD and the combined algorithms (3B42, 3B43 and TCA for both V5 and V6) while satellite instrument algorithms (PR, TMI and TCI) are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the WD rain rates while no significant difference exists between WD and the other products. The agreements between the TRMM satellite and WD gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI (-7.4%) and TPR (-31%) rain rates (compared to V5) results in better agreement between WD estimates and TMI in winter and TPR during summer.展开更多
Convective heat transfer associated with the circulation of porefluid in porous rocks and fractures within the upper crust of the Earth is substantial when the temperature gradient is sufficiently high. In order to un...Convective heat transfer associated with the circulation of porefluid in porous rocks and fractures within the upper crust of the Earth is substantial when the temperature gradient is sufficiently high. In order to understand the process of Snpolymetallic mineralization in the Dachang ore district of Guangxi, a finite element method has been used in this study to simulate both pore-fluid flow and heat transfer in this district. On the basis of related geological, tectonic and geophysical constraints, a computational model was established. It enables a computational simulation and sensitivity analysis to be carried out for investigating ore-forming pore-fluid flow and other key factors that may affect hydrothermal ore genesis in the district. The related simulation results have indicated that: (1) permeable fault zones in the Dacbang ore district can serve as preferential pathways for pore-fluid flow on a regional-scale; and (2) the pore-fluid flow can affect the salinity distribution. This latter factor is part of the reason why Sn-polymetallic mineralization has taken place in this district.展开更多
The Limahe intrusion is a typical rock hosting Cu-Ni sulfide deposit in the Panxi district. The major element, trace element and Sr-Nd isotopic geochemical data are reported in this study both firstly and systemically...The Limahe intrusion is a typical rock hosting Cu-Ni sulfide deposit in the Panxi district. The major element, trace element and Sr-Nd isotopic geochemical data are reported in this study both firstly and systemically. Age-corrected (87Sr/86Sr) and εNd(t) isotope values, ranging from 0.687062 to 0.709298, from -0.6 to -4.13 respectively, are partly overlap the field of the Emeishan basalt and OIB, and they lie between upper crust and OIB generally. The similar patterns between the Limahe intrusion and the picrites of the Emeishan large igneous province imply the genetic relationship to the Emeishan basalts. Their lower Nb/U (〈30), higher (La/Nb)pM and (Th/Ta)pM ratio values (〉1) indicate contamination of the upper crust material. The correlation between MgO and major oxides reflects the fractional crystallization of olivine, clinopyroxene and minor plagioclase in the deep-seated chamber. Therefore increased SiO2 and lowered FeO by the upper crustal contamination may trigger immiscible sulfide melt, which then flowed along the structural fracture and intruded into gabbrodiorite, resulting in the formation of Cu-Ni sulfide orebody.展开更多
Ganzhou District is an oasis city in the Zhangye Municipality of Gansu Province, China. Based on multi-temporal TM and ETM satellite remote sensing data in 1985, 1996, 2000, and 2012, and by using corrected figures of...Ganzhou District is an oasis city in the Zhangye Municipality of Gansu Province, China. Based on multi-temporal TM and ETM satellite remote sensing data in 1985, 1996, 2000, and 2012, and by using corrected figures of land use status over the same periods, the spatial area of Ganzhou District since 1985 was extracted with statistical methods, and urban spatial expansion was measured by quantitative research methods. The characteristics of spatial expansion of Ganzhou District were analyzed by urban expansion rate, expansion intensity index, compactness, fractal dimension, and the city center shift method. The results showed that the built-up area of Ganzhou District increased by 3.46 times during 1985-2012. The expansion in 1985 1996 was slow, during 1996 2000 it was rapid, and during 2000-2012 it was at a high speed. This city mainly expanded to the northeast and northwest. Government decision making had a decisive influence on urban expansion. Initially the expansion was uniform, but later the local tfansportation, economy, resources, population, and national policies factors had an obvious influence on urban expansion.展开更多
Objective Lhasa terrane has recorded the geologic history conceming the formation and evolution of Paleo-Tethys and the intra-continental convergence in Qinghai-Tibet Plateau (Yin and Harrison, 2000). Previous inve...Objective Lhasa terrane has recorded the geologic history conceming the formation and evolution of Paleo-Tethys and the intra-continental convergence in Qinghai-Tibet Plateau (Yin and Harrison, 2000). Previous investigations have focused on the initial timing of the India-Asia collision and the Cretaceous-Cenozoic magmatism and sedimentation (Wang Tianyang et al., 2017), however, there are only few studies concerning the Paleozoic evolution in Lhasa terrane. This paper mainly reports a new discovery of 341 Ma gabbro, which is located in the Xiongcun copper-gold district at the southern margin of Lhasa terrane, Tibet. As an important magmatic record during the Paleozoic evolution process of Lhasa terrane, the Early Carboniferous Xiongcun gabbro will provide new constraints for the tectonic evolution of Paleo-Tethys Ocean in the Late Devonian to Early Carboniferous.展开更多
In this work is developed a proposal of environment indicators needed for the Environment Impact Assessment (EIA) process in Mexico’s Federal District (FD);through which are authorized the construction and realizatio...In this work is developed a proposal of environment indicators needed for the Environment Impact Assessment (EIA) process in Mexico’s Federal District (FD);through which are authorized the construction and realization of different work actions and activities. The methodology is based on the combination of cabinet and field work, performed in three stages. In the first, a documental review was carried out within the topic of Environment Impact (EI), the EIA and the study area, with a subsequent analysis of the environment indicators at an international, national and regional scale. In the second, the systematization of information was performed for the sixteen study cases at a local scale and the organization and analysis of a data base with the allotted information. And in the last stage, a field work was realized with participative observations in three verification sites and interview applications to the principal actors of the EIA process. These results allowed: to determine the main limitations within the EIA process (methodological, technical and operational), to propose an indicators scheme, and to formulate recommendations focused on the improvement of this Environment Public Policy instrument.展开更多
This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as th...This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as the basis. We combined social scientific methods with a GIS method using a behavior accessibility model from the perspectives of fairness of urban green space allocation based on social geography, geographic information science, management science and many other related discipline theories. The results show that: 1) Most of the urban green space distribution presents an unbalanced phenomenon, and it does not match with the population distribution; 2) We found some differences in the accessibility of the population with different attributes and opportunities to use and enjoy the urban green spaces, mainly due to: the dual social and spatial attributes of the residents and the serious stratum differentiation generated were the internal causes; the residential space differentiation and the pursuit of economic and real estate development were the direct causes; and unreasonable planning, in regard to the fact that government policies did not give consideration to efficiency and fairness, was also an important factor.展开更多
Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused ch...Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused changes in landscape patterns and impacts on the ecological environment.It is unknown how the mechanism of land use affects the landscape pattern at different scales.The Hantai District,a typical human settlement in the mountain area in Shaanxi,China,was chosen as the study area.Based on the remote sensing images,the mathematical models and landscape indexes were adopted to evaluate the impact of land use change from 1998 to 2017 on the landscape pattern at different scales,and its main driving forces were analyzed.The results showed that the urbanized land expanded largest from 15.39%to 24.30%,and cultivated land experienced the largest decline from 43.54%to 35.35%.Changes in land use have made the patch morphology of most land types developed from a natural random to a sawtooth shape,and its spatial pattern evolved from a ruleset to a fragmented expansion.This reflects the continuous strengthening of human intervention in the process of regional development.Under the jurisdiction of Hantai District,the biggest change in landscape pattern is in Hanzhong City and Qili Town.The improved economy and increasing population and urbanization rate were the main factors that cause these changes.This research could provide necessary information for understanding the evolution mechanism of land resources in mountainous human settlements for mountainous areas with significant geomorphic differentiation.展开更多
基金supported by the Shandong Province Natural Science Foundation Youth Branch(ZR2023QC157)the National Natural Science Foundation of China(51979233)+1 种基金the Key Research and Development Project of Shaanxi Province(2022KW-47,2022NY-220)the Heze University Doctoral Research Fund(XY21BS24,XY22BS17).
文摘Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.
文摘Characteristics of road landscaping were analyzed,as a kind of "linear" landscaping,it could be classified into urban street landscaping,urban ring road and expressway landscaping.Differences between road landscaping projects and other garden landscaping projects or construction projects were analyzed.Landscaping project for the South 3rd Ring Road of Xi'an City(in Yanta District)was taken for an example to summarize construction experience,discuss present conditions and features of garden landscaping supervision in China.The artistic and physiological properties of garden landscaping,as well as the supervision during maintenance period were stressed,but it was also pointed out that garden landscaping supervision in China was actually not given sufficient attention.On this basis,key points in the supervision of road landscaping project were proposed:understanding design ideas,selection of landscape plants,quality control of concealed works,prevention and control of diseases and insects,construction safety management and overall image;only by effectively implementing these key points,a high-quality road landscaping project could be realized to improve the image of a city and beautify its environment.
文摘[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns (corn field, cherry tree land, wood land) were selected from Hongta District, Yuxi City, and under these three patterns, soil microbial quantity and activity were studied. [Result] Under the three land use patterns, soil microorganisms were domi- nated by bacteria; soil microbial quantity ranked as wood land's〉cheery tree land's〉 corn field's; and total microbial activity, catalase activity and urease activity all ranked as cherry tree land's〉wood land's〉corn field's. [Conclusion] Soil microbial activity and functions are related to farmland management measures, as well as land use pattern and soil nutrients.
文摘This study aimed to provide theoretical basis for an optimized land use of Xigu District in Lanzhou City,Gansu Province.With the support of GIS platform,structural characteristics of 11 land use types in Xigu District were analyzed by utilizing fragmentation degree,shape index,fractal dimension,diversity and such landscape pattern indices.
文摘Mountains and waters serve as important elements for urban spatial mor-phology, structure and eco-environment. Since scientist Qian Xuesen proposed the concept of landscape city, it has been an effective way for urban development in case of thousand-city in the same appearance. In the study, we analyzed the con-cept, connotation and approaches and proposed the ways to landscape city.
基金Sponsored by Key Project of National Social Science Foundation(08ZD027)~~
文摘Edge effect theory is introduced in this study to define the concepts and connotations of marginal zone and edge effect in the planning of rural tourism,and it is proposed that edge effect should be paid more attention.By taking the rural tourism planning of Lintong District for an example,the development and realization approaches of edge effect in rural tourism planning are further analyzed from both overall and detailed planning.
文摘Under the background of new urbanization, rural buildings' energy efficiency retrofit is an essential part of the overall work of the building energy conservation. Therefore, taking rural buildings in hot-summer and cold-winter zone as the research object, we carried out field investigation by combining geographical climate charactedstics with social-economic conditions and analyzed the energy consumption and energy conservation of rural buildings in hot-summer and cold-winter zone. On the basis of the investigation and analysis, this paper pointed out the questions with its energy efficiency retrofit and proposed the energy-saving strategy which was suitable for rural buildings in hot-summer and cold-winter zone based on people's livelihood and development.
基金Supported by State Key Laboratory of Loess and Quaternary Geology Open-end Fund(SKLLQG1426)Post-doctoral Foundation and National Natural Science Foundation of China(41102107)~~
文摘This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out earthquake disaster reduction planning for districts or countries in the northwest. With Hongsibao District in Wuzhong City, Ningxia Province as an example, this article analyzed in detail the present situation and the special problems of earthquake disaster reduction planning in Northwest China. The relevant solving measures were put forward in order to offer a reference for the scientific establishment and effective implementation of earth- quake disaster reduction planning in Northwest China. The foundation of earthquake disaster reduction in the Hongsibao District is still very weak, there is a single earthquake monitoring means, the emergency rescue system is not complete, the working mechanism is not perfect, and the lack of funding for the work of earthquake disaster reduction.
文摘With the case study of Honggutan New District as reference,this paper elaborated the significance of urban green space;the ecological function and cultural function of green landscape which were respectively manifested in the aspect of living and production and in the aspect of accumulation,sedimentation and renovation mark of urban history development.It also explained the composition of wetland region,the situation that there existed quite a lot of wetland,wetland flower species and landscape types.And the existing problems in the construction of Honggutan green landscape were analyzed,which were the fact that the spatial distribution of plants was unreasonable and impracticable;that the function of green space hadn't been fully displayed,lack of participation;that the landscaping plant was monotonous,short of cultural deposits.On the basis of the design theory of green landscape and the living examples of some developed cities,the regionality of urban green landscape was studied;the design principles of elegance,functionality,people-orientation,regional culture's continuity and ecology were put forward,aiming at providing reference for using different factors of practical measures to achieve landscape eco-design with geographical features.
基金Under the auspices of the National Natural Science Foundationof China(No. 40171069).
文摘ABSTRACT: At the study area of Xigu District in Lanzhou City, using RS & GIS as tools we apply Diversity, Dominance, Fragmentation , Isolation and so on to study the quantitative, fractal and spatial characters of landscapes’ structures in the four sub-regions divided by the morphological features. Using the Fractal Theory to establish the fractal structure models, we analyze the complexity and stability of various landscapes’ distribution with fractal dimension value. The spatial distribution characteristics of landscape mosaic structure are also expounded. At the end of the paper we discuss the relevant problems on the main factors which control and effect on the spatial pattern of landscapes as well as on landscape optimization and management.
文摘This paper compares monthly and seasonal rain rates derived from the Version 5 (V5) and Version 6 (V6) TRMM Precipitation Radar (TPR, TSDIS reference 2A25), TRMM Microwave Imager (TMI, 2A12), TRMM Combined Instrument (TCI, 2B31), TRMM calibrated IR rain estimates (3B42) and TRMM merged gauge and satellite analysis (3B43) algorithms over New Mexico (NM) with rain gauge analyses provided by the New Mexico water districts (WD). The average rain rates over the NM region for 1998- 2002 are 0.91 mm d^-1 for WD and 0.75, 1.38, 1.49, 1.27, and 1.07 mm d^-1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d^-1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with WD rain rates and the daily TRMM mission index (TPR and TMI) suggests that the low bias of V5 3B43 for the wet months (summer to early fall) may be due to the non-inclusion of some rain events in the operational gauge analyses that. are used in the production of V5 3B43. Correlation analyses show that the WD rain rates vary in phase, with higher correlation between neighboring WDs. High temporal correlations (〉0.8) exist between WD and the combined algorithms (3B42, 3B43 and TCA for both V5 and V6) while satellite instrument algorithms (PR, TMI and TCI) are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the WD rain rates while no significant difference exists between WD and the other products. The agreements between the TRMM satellite and WD gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI (-7.4%) and TPR (-31%) rain rates (compared to V5) results in better agreement between WD estimates and TMI in winter and TPR during summer.
基金financially supported by the Natural Science Foundation of China(Grant No:10872219)
文摘Convective heat transfer associated with the circulation of porefluid in porous rocks and fractures within the upper crust of the Earth is substantial when the temperature gradient is sufficiently high. In order to understand the process of Snpolymetallic mineralization in the Dachang ore district of Guangxi, a finite element method has been used in this study to simulate both pore-fluid flow and heat transfer in this district. On the basis of related geological, tectonic and geophysical constraints, a computational model was established. It enables a computational simulation and sensitivity analysis to be carried out for investigating ore-forming pore-fluid flow and other key factors that may affect hydrothermal ore genesis in the district. The related simulation results have indicated that: (1) permeable fault zones in the Dacbang ore district can serve as preferential pathways for pore-fluid flow on a regional-scale; and (2) the pore-fluid flow can affect the salinity distribution. This latter factor is part of the reason why Sn-polymetallic mineralization has taken place in this district.
文摘The Limahe intrusion is a typical rock hosting Cu-Ni sulfide deposit in the Panxi district. The major element, trace element and Sr-Nd isotopic geochemical data are reported in this study both firstly and systemically. Age-corrected (87Sr/86Sr) and εNd(t) isotope values, ranging from 0.687062 to 0.709298, from -0.6 to -4.13 respectively, are partly overlap the field of the Emeishan basalt and OIB, and they lie between upper crust and OIB generally. The similar patterns between the Limahe intrusion and the picrites of the Emeishan large igneous province imply the genetic relationship to the Emeishan basalts. Their lower Nb/U (〈30), higher (La/Nb)pM and (Th/Ta)pM ratio values (〉1) indicate contamination of the upper crust material. The correlation between MgO and major oxides reflects the fractional crystallization of olivine, clinopyroxene and minor plagioclase in the deep-seated chamber. Therefore increased SiO2 and lowered FeO by the upper crustal contamination may trigger immiscible sulfide melt, which then flowed along the structural fracture and intruded into gabbrodiorite, resulting in the formation of Cu-Ni sulfide orebody.
基金supported by a project of the National Natural Science Foundation of China(Grant No.41271133)the improvement plan of scientific research ability in Northwest Normal University(NWNU-LKQN-13-10)Open-ended fund of State Key Laboratory of Cryosphere Sciences,Chinese Academy of Sciences(SKLCS-OP-2014-11)
文摘Ganzhou District is an oasis city in the Zhangye Municipality of Gansu Province, China. Based on multi-temporal TM and ETM satellite remote sensing data in 1985, 1996, 2000, and 2012, and by using corrected figures of land use status over the same periods, the spatial area of Ganzhou District since 1985 was extracted with statistical methods, and urban spatial expansion was measured by quantitative research methods. The characteristics of spatial expansion of Ganzhou District were analyzed by urban expansion rate, expansion intensity index, compactness, fractal dimension, and the city center shift method. The results showed that the built-up area of Ganzhou District increased by 3.46 times during 1985-2012. The expansion in 1985 1996 was slow, during 1996 2000 it was rapid, and during 2000-2012 it was at a high speed. This city mainly expanded to the northeast and northwest. Government decision making had a decisive influence on urban expansion. Initially the expansion was uniform, but later the local tfansportation, economy, resources, population, and national policies factors had an obvious influence on urban expansion.
基金financially supported by the National Natural Science Foundation of China(grant No.41502079)China Geological Survey(grants No.[2012]03-002-055 and [2014]01-028-042)
文摘Objective Lhasa terrane has recorded the geologic history conceming the formation and evolution of Paleo-Tethys and the intra-continental convergence in Qinghai-Tibet Plateau (Yin and Harrison, 2000). Previous investigations have focused on the initial timing of the India-Asia collision and the Cretaceous-Cenozoic magmatism and sedimentation (Wang Tianyang et al., 2017), however, there are only few studies concerning the Paleozoic evolution in Lhasa terrane. This paper mainly reports a new discovery of 341 Ma gabbro, which is located in the Xiongcun copper-gold district at the southern margin of Lhasa terrane, Tibet. As an important magmatic record during the Paleozoic evolution process of Lhasa terrane, the Early Carboniferous Xiongcun gabbro will provide new constraints for the tectonic evolution of Paleo-Tethys Ocean in the Late Devonian to Early Carboniferous.
文摘In this work is developed a proposal of environment indicators needed for the Environment Impact Assessment (EIA) process in Mexico’s Federal District (FD);through which are authorized the construction and realization of different work actions and activities. The methodology is based on the combination of cabinet and field work, performed in three stages. In the first, a documental review was carried out within the topic of Environment Impact (EI), the EIA and the study area, with a subsequent analysis of the environment indicators at an international, national and regional scale. In the second, the systematization of information was performed for the sixteen study cases at a local scale and the organization and analysis of a data base with the allotted information. And in the last stage, a field work was realized with participative observations in three verification sites and interview applications to the principal actors of the EIA process. These results allowed: to determine the main limitations within the EIA process (methodological, technical and operational), to propose an indicators scheme, and to formulate recommendations focused on the improvement of this Environment Public Policy instrument.
基金Under the auspices of National Natural Science Foundation of China(No.41471140)
文摘This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as the basis. We combined social scientific methods with a GIS method using a behavior accessibility model from the perspectives of fairness of urban green space allocation based on social geography, geographic information science, management science and many other related discipline theories. The results show that: 1) Most of the urban green space distribution presents an unbalanced phenomenon, and it does not match with the population distribution; 2) We found some differences in the accessibility of the population with different attributes and opportunities to use and enjoy the urban green spaces, mainly due to: the dual social and spatial attributes of the residents and the serious stratum differentiation generated were the internal causes; the residential space differentiation and the pursuit of economic and real estate development were the direct causes; and unreasonable planning, in regard to the fact that government policies did not give consideration to efficiency and fairness, was also an important factor.
基金funded by Natural Science Foundation of China(51378067)the Natural Science Foundation of Shaanxi(806215594019)。
文摘Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused changes in landscape patterns and impacts on the ecological environment.It is unknown how the mechanism of land use affects the landscape pattern at different scales.The Hantai District,a typical human settlement in the mountain area in Shaanxi,China,was chosen as the study area.Based on the remote sensing images,the mathematical models and landscape indexes were adopted to evaluate the impact of land use change from 1998 to 2017 on the landscape pattern at different scales,and its main driving forces were analyzed.The results showed that the urbanized land expanded largest from 15.39%to 24.30%,and cultivated land experienced the largest decline from 43.54%to 35.35%.Changes in land use have made the patch morphology of most land types developed from a natural random to a sawtooth shape,and its spatial pattern evolved from a ruleset to a fragmented expansion.This reflects the continuous strengthening of human intervention in the process of regional development.Under the jurisdiction of Hantai District,the biggest change in landscape pattern is in Hanzhong City and Qili Town.The improved economy and increasing population and urbanization rate were the main factors that cause these changes.This research could provide necessary information for understanding the evolution mechanism of land resources in mountainous human settlements for mountainous areas with significant geomorphic differentiation.