Based on China Family Panel Studies(CFPS)2018 data,the multiple linear regression model is used to analyze the effects of Internet use on women’s depression,and to test the robustness of the regression results.At the...Based on China Family Panel Studies(CFPS)2018 data,the multiple linear regression model is used to analyze the effects of Internet use on women’s depression,and to test the robustness of the regression results.At the same time,the effects of Internet use on mental health of women with different residence,age,marital status and physical health status are analyzed.Then,we can obtain that Internet use has a significant promoting effect on women’s mental health,while the degree of Internet use has a significant inhibitory effect on women’s mental health.In addition,the study found that women’s age,education,place of residence,marital status,length of sleep,working status and physical health status are the main factors affecting the mental health of Chinese women.In the heterogeneity investigation of residence,age,marital status and physical health status,Internet use has a greater negative impact on the Center for Epidemiological Studies Depression Scale(CES-D8)scores of women in rural areas,has a significant positive impact on the mental health of middle-aged and elderly women or women with spouses,and has a positive impact on the mental health of physically unhealthy women.Therefore,in view of women’s mental health needs and the problems existing in the use of the Internet,this paper puts forward some suggestions to further improve the overall mental health level of women.展开更多
The dynamic transformation of land use and land cover has emerged as a crucial aspect in the effective management of natural resources and the continual monitoring of environmental shifts. This study focused on the la...The dynamic transformation of land use and land cover has emerged as a crucial aspect in the effective management of natural resources and the continual monitoring of environmental shifts. This study focused on the land use and land cover (LULC) changes within the catchment area of the Godavari River, assessing the repercussions of land and water resource exploitation. Utilizing LANDSAT satellite images from 2009, 2014, and 2019, this research employed supervised classification through the Quantum Geographic Information System (QGIS) software’s SCP plugin. Maximum likelihood classification algorithm was used for the assessment of supervised land use classification. Seven distinct LULC classes—forest, irrigated cropland, agricultural land (fallow), barren land, shrub land, water, and urban land—are delineated for classification purposes. The study revealed substantial changes in the Godavari basin’s land use patterns over the ten-year period from 2009 to 2019. Spatial and temporal dynamics of land use/cover changes (2009-2019) were quantified using three Satellite/Landsat images, a supervised classification algorithm and the post classification change detection technique in GIS. The total study area of the Godavari basin in Maharashtra encompasses 5138175.48 hectares. Notably, the built-up area increased from 0.14% in 2009 to 1.94% in 2019. The proportion of irrigated cropland, which was 62.32% in 2009, declined to 41.52% in 2019. Shrub land witnessed a noteworthy increase from 0.05% to 2.05% over the last decade. The key findings underscored significant declines in barren land, agricultural land, and irrigated cropland, juxtaposed with an expansion in forest land, shrub land, and urban land. The classification methodology achieved an overall accuracy of 80%, with a Kappa Statistic of 71.9% for the satellite images. The overall classification accuracy along with the Kappa value for 2009, 2014 and 2019 supervised land use land cover classification was good enough to detect the changing scenarios of Godavari River basin under study. These findings provide valuable insights for discerning land utilization across various categories, facilitating the adoption of appropriate strategies for sustainable land use in the region.展开更多
Faced with the proliferation of quarries extracting silty sand and river sand used in the building and public works sector in Togo, recognition of the granular properties of these materials remains a major challenge f...Faced with the proliferation of quarries extracting silty sand and river sand used in the building and public works sector in Togo, recognition of the granular properties of these materials remains a major challenge for builders. This study aims to take stock of the use of sand in construction in Togo. One hundred and eighteen (118) sand quarries in operation, including thirty-eight (38) silty sand quarries and eighty (80) river sand quarries, were identified following surveys carried out among stakeholders involved in the chain of construction on 40% of the national territory. It appears from these surveys that river sands (59.43% to 84.68%) are prioritized over silty sands (15.32% to 40.57%). Three (3) main reasons are behind the choice of sand type;namely, proximity (28%), cleanliness (25%), good appearance (25%). These three (03) reasons partly explain the strong dependence of users on the sands located in their vicinity as well as the related expenses. Thus, making data available on the characteristics of sand, the materials most used in construction in Togo, would contribute to improving the housing conditions of the Togolese population. .展开更多
In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision fact...In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision factors on site selection of affordable housing through a literature review to construct a hierarchy model of those factors identifying the weight of each factor by an analytic hierarchy process AHP .Based on those weight factors the CA-MAS model is designed. Nanjing city is taken as an example to verify the feasibility of the model.The results show that the CA-MAS model is pragmatic and effective in simulating evolution of affordable housing land use which also promotes the fundamental understanding and perception of the development of affordable housing and urbanization.展开更多
Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pione...Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pioneer the model of sustainable development in that area. Concerning Qianjiang District of Chongqing Municipality,huge change of land use model,mainly embodied in the unceasing increase of construction land and gradual decrease of agricultural use land,has taken place in recent years. To explore the eco-friendly land use model in mountainous area,Qianjiang District was chosen as the study object in the present study. Via analyzing the changes in land use model,we found that related eco-environment restrictive factors mainly regional climatic change,soil texture,hydrological environment as well as soil erosion and land degradation,etc. And based on these results,we further analyzed the effect of land use change on eco-environment and the factors restricting the maintenance of eco-environment and regional development,finally put forward the counter measures for balancing land use and co-environment in mountainous area. The results will be important for the development of social economy and eco-system construction in Qianjiang District.展开更多
Boreal forests play an important role in global environment systems. Understanding boreal forest ecosystem structure and function requires accurate monitoring and estimating of forest canopy and biomass. We used parti...Boreal forests play an important role in global environment systems. Understanding boreal forest ecosystem structure and function requires accurate monitoring and estimating of forest canopy and biomass. We used partial least square regression (PLSR) models to relate forest parameters, i.e. canopy closure density and above ground tree biomass, to Landsat ETM+ data. The established models were optimized according to the variable importance for projection (VIP) criterion and the bootstrap method, and their performance was compared using several statistical indices. All variables selected by the VIP criterion passed the bootstrap test (p〈0.05). The simplified models without insignificant variables (VIP 〈1) performed as well as the full model but with less computation time. The relative root mean square error (RMSE%) was 29% for canopy closure density, and 58% for above ground tree biomass. We conclude that PLSR can be an effective method for estimating canopy closure density and above ground biomass.展开更多
This study investigated and simulated land use patterns in Beijing for the year 2000 and the year 2005 from the actual land use data for the year 1995 and the year 2000,respectively,by combining spatial land allocatio...This study investigated and simulated land use patterns in Beijing for the year 2000 and the year 2005 from the actual land use data for the year 1995 and the year 2000,respectively,by combining spatial land allocation simulation using the CLUE-S model,and numerical land demand prediction using the Markov model.The simulations for 2000 and 2005 were confirmed to be generally accurate using Kappa indices.Then the land-use scenarios for Beijing in 2015 were simulated assuming two modes of development:1) urban development following existing trends;and 2) under a strict farmland control.The simulations suggested that under either mode,urbanized areas would expand at the expense of land for other uses.This expansion was predicted to dominate the land-use conversions between 2005 and 2015,and was expected to be accompanied by an extensive loss of farmland.The key susceptible to land-use changes were found to be located at the central urban Beijing and the surrounding regions including Yanqing County,Changping District and Fangshan District.Also,the simulations predicted a considerable expansion of urban/suburban areas in the mountainous regions of Beijing,suggesting a need for priority monitoring and protection.展开更多
Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapi...Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapid economic development in the last years. All of the above changes will affect sustainable development in the next century. The Chinese Academy of Sciences is conducting a study of land use/cover change over the last ten years based on the integration of remote sensing and GIS technology to establish a multitemporal database covering all of China. Fundamental data for land use/cover for the year 1996 has already been developed by the Chinese Academy of Sciences. In order to reconstruct fundamental land use/cover data for the year 1986, a central data processing and analyzing system and a regional data acquisition, processing and analyzing system have been established and are joined together as a network. After the 1986 database is established, the comparative research on the reduction in arable land, urbanization, desertification, changes in forest and grassland, and lake and wetland land use/cover change will be carried out. In addition, a transect for a key regional comparative study was selected along the Changjiang (Yangtze) River. The driving forces of these changes also will be extracted. The result of this study will be not only make a contribution to global land use/cover change research, but will also support decision making for sustainable national development.展开更多
Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes (LUCC) in the Zhejiang coastal region wi...Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes (LUCC) in the Zhejiang coastal region with a stratified unsupervised classification technique in conjunction with visual interpretation and to attempt an identification of the socioeconomic driving forces. In level I an overall accurate classification was achieved using a modified Anderson's Ⅰ/Ⅱ/Ⅲ-level classification scheme. The overall accuracy of the land use classification at Anderson level Ⅰ were 89.7% (1985), 91.6% (1993), and 90.4% (2001). The most rapid land use change was a dramatic increase in urban or built-up areas, which quadrupled from 1985 to 2001. Over 90% of this newly expanded built-up area was originally paddy fields or other croplands. In different parts of the Zhejiang coastal region, urban land expansion was spatially uneven. Temporally, land use development did not stabilized, and the two study periods of time (1985-1993 and 1993-2001) had different transition styles. Socioeconomic factors, such as gross domestic product, total population, and financial expenditure, were all highly correlated with the expansion of urban or built-up areas. Based on the degree of urban sprawl and socioeconomic factors, cities and towns were further divided into six subgroups, which may help decision makers improve land use for the region.展开更多
A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning Sys...A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.展开更多
We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase ...We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase shift and contrast of the interference fringe are experimentally investigated. The results show that the contrast of the interference fringe is well held when the platform is rotated, and the phase shift of the interference fringe is linearly proportional to the rotation rate of the platform. The long-term stability, which is evaluated by the overlapped Allan deviation, is 8.5 × 10^-6 rad/s over the integrating time of 1000s.展开更多
Fuqing County of southeast China has witnessed significant land use changes during the last decade. Re mote sensing technology using multitemporal Landsat TM images was used to characterize land use types and to monit...Fuqing County of southeast China has witnessed significant land use changes during the last decade. Re mote sensing technology using multitemporal Landsat TM images was used to characterize land use types and to monitor land use changes in the county. Two TM scenes from 1991 and 1996 were used to cover the county and a five-year time period. Digital image processing was carried out for the remotely sensed data to produce classified images. The images were further processed using GIS software to generate GIS databases so that the data could be further spatially analyzed taking the advantages of the software. Land use change areas were determined by using the change detection technique. The comparison of the two classified TM images using the above technologies reveals that during the five study years, a large area of arable lands in the county has been lost and deforestation has taken place largely because of the dramatic in crease in built-up land and orchard. The conclusive statistical information is useful to understand the processes, causes and impacts of the land use changes in the county. The major driving force to the land use changes in the county ap peared to be the rapid economic development. The decision makers of the county have to pay more attention to the land use changes for the county’s sustainable development.展开更多
Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and p...Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and prosperous sea coast there are a total area ofover 120 x 10~3ha, with a population of 735 000, accruing some 500ha of new tidal land resourcescome from silt, sand and mud carried by the Changjiang River every year, extending about 140m peryear. This dynamic process of alluvial growth has run for some 1500 years. Mudflat on ChongmingIsland at the mouth of the Changjiang River is a resting ground for migratory birds and host morethan a hundred species, including rare cranes and geese. But the local people keep reclaiming thetidal land for economic development. Obviously, it is crucial to have a well-concerted plan forfuture exploitation. In this study, we attempted to investigate the status changes of land use andwild life habitats on Chongming Island in recent 10 years, and then analyzed different humanactivities and their effects on wild life habitats using satellite image data (1990, 1997 and 2000)as well as field survey. Based on the analysis, this study explored the relationships between islandgrowth and land use/cover change (LUCC), predicted what the habitat would be like in the future andtried to find more effective use of this new growing resource. At last, this study provided somepreliminary management plans for Chongming Island that will coordinate the development of localeconomies and the conservation of wild life and their habitats.展开更多
Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitabl...Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitable technique for the used sand. When the recycled sand is used as support sand, the used sand is only reused by dry process including breaking, screening, dust-removal, etc., and it is not necessary that the used sand is reclaimed with strongly rubbing and scraping method, but when the recycled sand is used as facing sand (or single sand), the used sand must be reclaimed by wet method for higher removal rate of the residual binders. The characteristics and the properties of the dry reused sand are compared with the wet reclaimed sand after combining the different use requirements of support sand and facing sand (or single sand), and above the most adaptive scheme has also been validated.展开更多
Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and cal...Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and calculated terrestrial vegetation carbon storage(VCS) for 2000 and 2015 using land surface area and traditional ellipsoid area. The land surface area is estimated by a triangular network on the high precision digital elevation model.The results showed that: 1) The VCS estimated by the surface area measurement in 2000 and 2015 were 0.676 and0.692 Pg C(1 Pg = 1015 g) higher than the VCS calculated using the ellipsoid area, respectively. 2) As the elevation increases, the differences between VCS estimated by surface area measurement and ellipsoid area measurement are expanding. Specially, a clear gap was present starting from an elevation of 500 m, with the relative error exceeds8.99%. 3) The total amount of carbon emitted due to land use change reached 0.114 Pg C. The conversions of forestland and grassland to other land use type are the main reasons of the loss of vegetation carbon storage, resulting in a total amount of biomass carbon storage decreased by 0.942 and 0.111 Pg C, respectively. This study was a preliminary exploration of incorporating land surface area as a factor in resource estimation, which can help more accurately understand the status of resources and the environment in the region.展开更多
The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynam...The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynamic hot-simulation testing machine. The results show that the AI sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s^-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the AI pieces prepared by no or conventional melt-treatment, hot deformation activation energy of AI sheets prepared by high-efficient melt-treatment is the smallest ( Q= 168.0kJ/mol), which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.展开更多
Remote sensing is one of the tool which is very important for the production of Land use and land cover maps through a process called image classification. For the image classification process to be successfully, seve...Remote sensing is one of the tool which is very important for the production of Land use and land cover maps through a process called image classification. For the image classification process to be successfully, several factors should be considered including availability of quality Landsat imagery and secondary data, a precise classification process and user’s experiences and expertise of the procedures. The objective of this research was to classify and map land-use/land-cover of the study area using remote sensing and Geospatial Information System (GIS) techniques. This research includes two sections (1) Landuse/Landcover (LULC) classification and (2) accuracy assessment. In this study supervised classification was performed using Non Parametric Rule. The major LULC classified were agriculture (65.0%), water body (4.0%), and built up areas (18.3%), mixed forest (5.2%), shrubs (7.0%), and Barren/bare land (0.5%). The study had an overall classification accuracy of 81.7% and kappa coefficient (K) of 0.722. The kappa coefficient is rated as substantial and hence the classified image found to be fit for further research. This study present essential source of information whereby planners and decision makers can use to sustainably plan the environment.展开更多
Due to inappropriate planning and management, accelerated urban growth and tremendous loss in land, especially cropland, have become a great challenge for sustainable urban development in China, especially in develope...Due to inappropriate planning and management, accelerated urban growth and tremendous loss in land, especially cropland, have become a great challenge for sustainable urban development in China, especially in developed urban area in the coastal regions; therefore, there is an urgent need to effectively detect and monitor the land use changes and provide accurate and timely information for planning and management. In this study a method combining principal component analysis (PCA) of multisensor satellite images from SPOT (systeme pour l'observation de la terre or earth observation satellite)-5 multispectral (XS) and Landsat-7 enhanced thematic mapper (ETM) panchromatic (PAN) data, and supervised classification was used to detect and analyze the dynamics of land use changes in the city proper of Hangzhou. The overall accuracy of the land use change detection was 90.67% and Kappa index was 0.89. The results indicated that there was a considerable land use change (10.03% of the total area) in the study area from 2001 to 2003, with three major types of land use conversions: from cropland into built-up land, construction site, and water area (fish pond). Changes from orchard land into built-up land were also detected. The method described in this study is feasible and useful for detecting rapid land use change in the urban area.展开更多
A methodology for the selection of the optimal land uses of the reclamation of mined areas is proposed. It takes into consideration several multi-nature criteria and constraints, including spatial constrains related t...A methodology for the selection of the optimal land uses of the reclamation of mined areas is proposed. It takes into consideration several multi-nature criteria and constraints, including spatial constrains related to the permissible land uses in certain parts of the mined area. The methodology combines desirability functions and evolution searching algorithms for selection of the optimal reclamation scheme. Its application for the reclamation planning of the Amynteon lignite surface mine in Greece indicated that it handles effectively spatial and non-spatial constraints and incorporates easily the decision-makers preferences regarding the reclamation strategy in the optimization procedure.展开更多
China is facing a severe water resource crisis, and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling s...China is facing a severe water resource crisis, and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling standards is an important way to deal with water shortage in agricultural production. Owing to the complex sources of municipal wastewater, there are multifarious pollutants in municipal wastewater. Improper use of wastewater can cause potential risks to agoenvironment, agricultural products safety, and human health. This article deals with the current situation and the development prospects of reclaimed wastewater for agricultural use in China and abroad; the potential risks to human health and environmental pollution from the reclaimed municipal wastewater for agricultural reuse are also discussed. And some countermeasures and advices of reclaimed municipal wastewater for safety of agricultural reuse are provided.展开更多
基金funded by the National Social Science Fund of China(Grant No.23BTJ069).
文摘Based on China Family Panel Studies(CFPS)2018 data,the multiple linear regression model is used to analyze the effects of Internet use on women’s depression,and to test the robustness of the regression results.At the same time,the effects of Internet use on mental health of women with different residence,age,marital status and physical health status are analyzed.Then,we can obtain that Internet use has a significant promoting effect on women’s mental health,while the degree of Internet use has a significant inhibitory effect on women’s mental health.In addition,the study found that women’s age,education,place of residence,marital status,length of sleep,working status and physical health status are the main factors affecting the mental health of Chinese women.In the heterogeneity investigation of residence,age,marital status and physical health status,Internet use has a greater negative impact on the Center for Epidemiological Studies Depression Scale(CES-D8)scores of women in rural areas,has a significant positive impact on the mental health of middle-aged and elderly women or women with spouses,and has a positive impact on the mental health of physically unhealthy women.Therefore,in view of women’s mental health needs and the problems existing in the use of the Internet,this paper puts forward some suggestions to further improve the overall mental health level of women.
文摘The dynamic transformation of land use and land cover has emerged as a crucial aspect in the effective management of natural resources and the continual monitoring of environmental shifts. This study focused on the land use and land cover (LULC) changes within the catchment area of the Godavari River, assessing the repercussions of land and water resource exploitation. Utilizing LANDSAT satellite images from 2009, 2014, and 2019, this research employed supervised classification through the Quantum Geographic Information System (QGIS) software’s SCP plugin. Maximum likelihood classification algorithm was used for the assessment of supervised land use classification. Seven distinct LULC classes—forest, irrigated cropland, agricultural land (fallow), barren land, shrub land, water, and urban land—are delineated for classification purposes. The study revealed substantial changes in the Godavari basin’s land use patterns over the ten-year period from 2009 to 2019. Spatial and temporal dynamics of land use/cover changes (2009-2019) were quantified using three Satellite/Landsat images, a supervised classification algorithm and the post classification change detection technique in GIS. The total study area of the Godavari basin in Maharashtra encompasses 5138175.48 hectares. Notably, the built-up area increased from 0.14% in 2009 to 1.94% in 2019. The proportion of irrigated cropland, which was 62.32% in 2009, declined to 41.52% in 2019. Shrub land witnessed a noteworthy increase from 0.05% to 2.05% over the last decade. The key findings underscored significant declines in barren land, agricultural land, and irrigated cropland, juxtaposed with an expansion in forest land, shrub land, and urban land. The classification methodology achieved an overall accuracy of 80%, with a Kappa Statistic of 71.9% for the satellite images. The overall classification accuracy along with the Kappa value for 2009, 2014 and 2019 supervised land use land cover classification was good enough to detect the changing scenarios of Godavari River basin under study. These findings provide valuable insights for discerning land utilization across various categories, facilitating the adoption of appropriate strategies for sustainable land use in the region.
文摘Faced with the proliferation of quarries extracting silty sand and river sand used in the building and public works sector in Togo, recognition of the granular properties of these materials remains a major challenge for builders. This study aims to take stock of the use of sand in construction in Togo. One hundred and eighteen (118) sand quarries in operation, including thirty-eight (38) silty sand quarries and eighty (80) river sand quarries, were identified following surveys carried out among stakeholders involved in the chain of construction on 40% of the national territory. It appears from these surveys that river sands (59.43% to 84.68%) are prioritized over silty sands (15.32% to 40.57%). Three (3) main reasons are behind the choice of sand type;namely, proximity (28%), cleanliness (25%), good appearance (25%). These three (03) reasons partly explain the strong dependence of users on the sands located in their vicinity as well as the related expenses. Thus, making data available on the characteristics of sand, the materials most used in construction in Togo, would contribute to improving the housing conditions of the Togolese population. .
基金The National Social Science Foundation of China(No.14AJY013)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXLX13_126)
文摘In order to simulate the evolution of affordable housing land use a dynamic model that combines cellular automata CA and a multi-agent system MAS is established.This paper aims to utilize the approach of decision factors on site selection of affordable housing through a literature review to construct a hierarchy model of those factors identifying the weight of each factor by an analytic hierarchy process AHP .Based on those weight factors the CA-MAS model is designed. Nanjing city is taken as an example to verify the feasibility of the model.The results show that the CA-MAS model is pragmatic and effective in simulating evolution of affordable housing land use which also promotes the fundamental understanding and perception of the development of affordable housing and urbanization.
文摘Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pioneer the model of sustainable development in that area. Concerning Qianjiang District of Chongqing Municipality,huge change of land use model,mainly embodied in the unceasing increase of construction land and gradual decrease of agricultural use land,has taken place in recent years. To explore the eco-friendly land use model in mountainous area,Qianjiang District was chosen as the study object in the present study. Via analyzing the changes in land use model,we found that related eco-environment restrictive factors mainly regional climatic change,soil texture,hydrological environment as well as soil erosion and land degradation,etc. And based on these results,we further analyzed the effect of land use change on eco-environment and the factors restricting the maintenance of eco-environment and regional development,finally put forward the counter measures for balancing land use and co-environment in mountainous area. The results will be important for the development of social economy and eco-system construction in Qianjiang District.
基金supported by the 948 Program of the State Forestry Administration (2009-4-43)the National Natura Science Foundation of China (No.30870420)
文摘Boreal forests play an important role in global environment systems. Understanding boreal forest ecosystem structure and function requires accurate monitoring and estimating of forest canopy and biomass. We used partial least square regression (PLSR) models to relate forest parameters, i.e. canopy closure density and above ground tree biomass, to Landsat ETM+ data. The established models were optimized according to the variable importance for projection (VIP) criterion and the bootstrap method, and their performance was compared using several statistical indices. All variables selected by the VIP criterion passed the bootstrap test (p〈0.05). The simplified models without insignificant variables (VIP 〈1) performed as well as the full model but with less computation time. The relative root mean square error (RMSE%) was 29% for canopy closure density, and 58% for above ground tree biomass. We conclude that PLSR can be an effective method for estimating canopy closure density and above ground biomass.
基金Under the auspices of National Natural Science Foundation of China (No. 70903061,41171440)National Public Benefit (Land) Research Foundation of China (No. 201111014)Fundamental Research Funds for the Central Universities (No. 2011YXL055)
文摘This study investigated and simulated land use patterns in Beijing for the year 2000 and the year 2005 from the actual land use data for the year 1995 and the year 2000,respectively,by combining spatial land allocation simulation using the CLUE-S model,and numerical land demand prediction using the Markov model.The simulations for 2000 and 2005 were confirmed to be generally accurate using Kappa indices.Then the land-use scenarios for Beijing in 2015 were simulated assuming two modes of development:1) urban development following existing trends;and 2) under a strict farmland control.The simulations suggested that under either mode,urbanized areas would expand at the expense of land for other uses.This expansion was predicted to dominate the land-use conversions between 2005 and 2015,and was expected to be accompanied by an extensive loss of farmland.The key susceptible to land-use changes were found to be located at the central urban Beijing and the surrounding regions including Yanqing County,Changping District and Fangshan District.Also,the simulations predicted a considerable expansion of urban/suburban areas in the mountainous regions of Beijing,suggesting a need for priority monitoring and protection.
文摘Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapid economic development in the last years. All of the above changes will affect sustainable development in the next century. The Chinese Academy of Sciences is conducting a study of land use/cover change over the last ten years based on the integration of remote sensing and GIS technology to establish a multitemporal database covering all of China. Fundamental data for land use/cover for the year 1996 has already been developed by the Chinese Academy of Sciences. In order to reconstruct fundamental land use/cover data for the year 1986, a central data processing and analyzing system and a regional data acquisition, processing and analyzing system have been established and are joined together as a network. After the 1986 database is established, the comparative research on the reduction in arable land, urbanization, desertification, changes in forest and grassland, and lake and wetland land use/cover change will be carried out. In addition, a transect for a key regional comparative study was selected along the Changjiang (Yangtze) River. The driving forces of these changes also will be extracted. The result of this study will be not only make a contribution to global land use/cover change research, but will also support decision making for sustainable national development.
文摘Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes (LUCC) in the Zhejiang coastal region with a stratified unsupervised classification technique in conjunction with visual interpretation and to attempt an identification of the socioeconomic driving forces. In level I an overall accurate classification was achieved using a modified Anderson's Ⅰ/Ⅱ/Ⅲ-level classification scheme. The overall accuracy of the land use classification at Anderson level Ⅰ were 89.7% (1985), 91.6% (1993), and 90.4% (2001). The most rapid land use change was a dramatic increase in urban or built-up areas, which quadrupled from 1985 to 2001. Over 90% of this newly expanded built-up area was originally paddy fields or other croplands. In different parts of the Zhejiang coastal region, urban land expansion was spatially uneven. Temporally, land use development did not stabilized, and the two study periods of time (1985-1993 and 1993-2001) had different transition styles. Socioeconomic factors, such as gross domestic product, total population, and financial expenditure, were all highly correlated with the expansion of urban or built-up areas. Based on the degree of urban sprawl and socioeconomic factors, cities and towns were further divided into six subgroups, which may help decision makers improve land use for the region.
基金Project supported by the Tingthanathikul Foundation of Thailand, the Provincial Natural Science Foun- dation of Jiangxi (No. 0230025) the Open Research Foundation of Hubei Provincial Key Labaratory of Waterlogged Disaster and Wetland Agriculture (No. H
文摘A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11227083 and 91536221
文摘We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase shift and contrast of the interference fringe are experimentally investigated. The results show that the contrast of the interference fringe is well held when the platform is rotated, and the phase shift of the interference fringe is linearly proportional to the rotation rate of the platform. The long-term stability, which is evaluated by the overlapped Allan deviation, is 8.5 × 10^-6 rad/s over the integrating time of 1000s.
文摘Fuqing County of southeast China has witnessed significant land use changes during the last decade. Re mote sensing technology using multitemporal Landsat TM images was used to characterize land use types and to monitor land use changes in the county. Two TM scenes from 1991 and 1996 were used to cover the county and a five-year time period. Digital image processing was carried out for the remotely sensed data to produce classified images. The images were further processed using GIS software to generate GIS databases so that the data could be further spatially analyzed taking the advantages of the software. Land use change areas were determined by using the change detection technique. The comparison of the two classified TM images using the above technologies reveals that during the five study years, a large area of arable lands in the county has been lost and deforestation has taken place largely because of the dramatic in crease in built-up land and orchard. The conclusive statistical information is useful to understand the processes, causes and impacts of the land use changes in the county. The major driving force to the land use changes in the county ap peared to be the rapid economic development. The decision makers of the county have to pay more attention to the land use changes for the county’s sustainable development.
文摘Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and prosperous sea coast there are a total area ofover 120 x 10~3ha, with a population of 735 000, accruing some 500ha of new tidal land resourcescome from silt, sand and mud carried by the Changjiang River every year, extending about 140m peryear. This dynamic process of alluvial growth has run for some 1500 years. Mudflat on ChongmingIsland at the mouth of the Changjiang River is a resting ground for migratory birds and host morethan a hundred species, including rare cranes and geese. But the local people keep reclaiming thetidal land for economic development. Obviously, it is crucial to have a well-concerted plan forfuture exploitation. In this study, we attempted to investigate the status changes of land use andwild life habitats on Chongming Island in recent 10 years, and then analyzed different humanactivities and their effects on wild life habitats using satellite image data (1990, 1997 and 2000)as well as field survey. Based on the analysis, this study explored the relationships between islandgrowth and land use/cover change (LUCC), predicted what the habitat would be like in the future andtried to find more effective use of this new growing resource. At last, this study provided somepreliminary management plans for Chongming Island that will coordinate the development of localeconomies and the conservation of wild life and their habitats.
文摘Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitable technique for the used sand. When the recycled sand is used as support sand, the used sand is only reused by dry process including breaking, screening, dust-removal, etc., and it is not necessary that the used sand is reclaimed with strongly rubbing and scraping method, but when the recycled sand is used as facing sand (or single sand), the used sand must be reclaimed by wet method for higher removal rate of the residual binders. The characteristics and the properties of the dry reused sand are compared with the wet reclaimed sand after combining the different use requirements of support sand and facing sand (or single sand), and above the most adaptive scheme has also been validated.
基金Under the auspices of the Fundamental Research Funds for the Central Universities(No.2019kfyXJJS026,2019QNA6024)
文摘Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and calculated terrestrial vegetation carbon storage(VCS) for 2000 and 2015 using land surface area and traditional ellipsoid area. The land surface area is estimated by a triangular network on the high precision digital elevation model.The results showed that: 1) The VCS estimated by the surface area measurement in 2000 and 2015 were 0.676 and0.692 Pg C(1 Pg = 1015 g) higher than the VCS calculated using the ellipsoid area, respectively. 2) As the elevation increases, the differences between VCS estimated by surface area measurement and ellipsoid area measurement are expanding. Specially, a clear gap was present starting from an elevation of 500 m, with the relative error exceeds8.99%. 3) The total amount of carbon emitted due to land use change reached 0.114 Pg C. The conversions of forestland and grassland to other land use type are the main reasons of the loss of vegetation carbon storage, resulting in a total amount of biomass carbon storage decreased by 0.942 and 0.111 Pg C, respectively. This study was a preliminary exploration of incorporating land surface area as a factor in resource estimation, which can help more accurately understand the status of resources and the environment in the region.
基金supported by the Fujian Provincial Natural Science Foundation(No.E0210011)the Educational Commission of Fujian province(No.K20014).
文摘The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynamic hot-simulation testing machine. The results show that the AI sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s^-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the AI pieces prepared by no or conventional melt-treatment, hot deformation activation energy of AI sheets prepared by high-efficient melt-treatment is the smallest ( Q= 168.0kJ/mol), which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.
文摘Remote sensing is one of the tool which is very important for the production of Land use and land cover maps through a process called image classification. For the image classification process to be successfully, several factors should be considered including availability of quality Landsat imagery and secondary data, a precise classification process and user’s experiences and expertise of the procedures. The objective of this research was to classify and map land-use/land-cover of the study area using remote sensing and Geospatial Information System (GIS) techniques. This research includes two sections (1) Landuse/Landcover (LULC) classification and (2) accuracy assessment. In this study supervised classification was performed using Non Parametric Rule. The major LULC classified were agriculture (65.0%), water body (4.0%), and built up areas (18.3%), mixed forest (5.2%), shrubs (7.0%), and Barren/bare land (0.5%). The study had an overall classification accuracy of 81.7% and kappa coefficient (K) of 0.722. The kappa coefficient is rated as substantial and hence the classified image found to be fit for further research. This study present essential source of information whereby planners and decision makers can use to sustainably plan the environment.
基金supported by the National Natural Science Foundation of China (NSFC) (No.30571112).
文摘Due to inappropriate planning and management, accelerated urban growth and tremendous loss in land, especially cropland, have become a great challenge for sustainable urban development in China, especially in developed urban area in the coastal regions; therefore, there is an urgent need to effectively detect and monitor the land use changes and provide accurate and timely information for planning and management. In this study a method combining principal component analysis (PCA) of multisensor satellite images from SPOT (systeme pour l'observation de la terre or earth observation satellite)-5 multispectral (XS) and Landsat-7 enhanced thematic mapper (ETM) panchromatic (PAN) data, and supervised classification was used to detect and analyze the dynamics of land use changes in the city proper of Hangzhou. The overall accuracy of the land use change detection was 90.67% and Kappa index was 0.89. The results indicated that there was a considerable land use change (10.03% of the total area) in the study area from 2001 to 2003, with three major types of land use conversions: from cropland into built-up land, construction site, and water area (fish pond). Changes from orchard land into built-up land were also detected. The method described in this study is feasible and useful for detecting rapid land use change in the urban area.
文摘A methodology for the selection of the optimal land uses of the reclamation of mined areas is proposed. It takes into consideration several multi-nature criteria and constraints, including spatial constrains related to the permissible land uses in certain parts of the mined area. The methodology combines desirability functions and evolution searching algorithms for selection of the optimal reclamation scheme. Its application for the reclamation planning of the Amynteon lignite surface mine in Greece indicated that it handles effectively spatial and non-spatial constraints and incorporates easily the decision-makers preferences regarding the reclamation strategy in the optimization procedure.
文摘China is facing a severe water resource crisis, and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling standards is an important way to deal with water shortage in agricultural production. Owing to the complex sources of municipal wastewater, there are multifarious pollutants in municipal wastewater. Improper use of wastewater can cause potential risks to agoenvironment, agricultural products safety, and human health. This article deals with the current situation and the development prospects of reclaimed wastewater for agricultural use in China and abroad; the potential risks to human health and environmental pollution from the reclaimed municipal wastewater for agricultural reuse are also discussed. And some countermeasures and advices of reclaimed municipal wastewater for safety of agricultural reuse are provided.