Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and ...Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.展开更多
Wetland ecosystems are important regulators of global climate change.Studying the spatiotemporal changes and driving mechanisms of their ecosystem service values(ESV)is beneficial for the sustainable development of we...Wetland ecosystems are important regulators of global climate change.Studying the spatiotemporal changes and driving mechanisms of their ecosystem service values(ESV)is beneficial for the sustainable development of wetlands.This paper uses the equivalent factor method,based on land use changes,to reveal the spatiotemporal evolution of the ecosystem service value in the Caohai National Nature Reserve(CNNR).The results show the following:①from 2000 to 2020,there was a significant decrease in the core zone s arable land area,with an increase in forest and water areas.Construction land mainly increased in the experimental area,and the grassland area showed a fluctuating change of first increasing and then decreasing;②in 2000,2010,and 2020,the ecosystem service value of the study area was 302 million,296 million,and 325 million yuan,respectively,showing a trend of fluctuating growth,with the value of wetland ecosystems playing a dominant role;③regulatory services are the main contributors to the ecosystem service value in the study area,with a contribution rate of 60%.Hydrological regulation is the ecosystem function with the highest value in wetland ecosystem services,contributing more than 35%to the ESV in all three periods;④in terms of spatial distribution,the core zone s ecosystem service value is dominant.Looking at the total ecosystem service value of the region,the core zone>the experimental area>the buffer zone.In terms of ESV per unit area,the core zone(89000 yuan/hm^(2))is significantly higher than the buffer zone(39100 yuan/hm^(2))and the experimental area(15800 yuan/hm^(2)).The study can provide a basis for research and spatial management of ecosystem services in wetland ecosystems and nature reserves.展开更多
Land use changes have significant impacts on the carbon balance in an urban ecosystem.When there is rapid development in urbanizing regions,land use changes have a dramatic effect on vegetation carbon storage(VCS).Thi...Land use changes have significant impacts on the carbon balance in an urban ecosystem.When there is rapid development in urbanizing regions,land use changes have a dramatic effect on vegetation carbon storage(VCS).This study investigates the impact of land use change on VCS in a period of rapid urbanization in Hangzhou,China.The results show that:1)from 2000 to 2015,land use in Hangzhou underwent huge changes,mainly reflected in decrease in cropland and wetland and the increased settlement.More than 34.58%of the land was transformed,and the land use changes are primarily characterized by a significant decrease in cropland due to the occupation by settlement.2)over the 15 years,changes in land use led to a decrease of 3.93×10^(5) t of VCS in the urban ecosystem.The large-scale transformation of cropland and wetland,which have a comparatively high carbon density,into land for settlement exerted a negative impact on VCS.3)The central city,which with the Circle-E/I/O mode,had the lowest comprehensive land use dynamic degree,leading to moderate land use change and an increase in VCS;Yuhang and Xiaoshan,which with Multicore-E/O/I mode and Fan-E/O/I modes,had a higher comprehensive land use dynamic degree,drastic changes in land use,and a decrease in VCS.This study proposes a reliable method of estimating changes in VCS,clarifies the relationship between land use change and VCS during rapid urbanization,and provides recommendations for sustainable urban development.展开更多
ABSTRACT: Based on the Landsat 5 and Landsat 7 TM images, the land use/cover change was detected in the upstream area of the Nenjiang River between 1995 and 2000. With the spatial analysis techniques of GIS, the maps ...ABSTRACT: Based on the Landsat 5 and Landsat 7 TM images, the land use/cover change was detected in the upstream area of the Nenjiang River between 1995 and 2000. With the spatial analysis techniques of GIS, the maps of land use degree and its change within this period were produced. To identify the causes of changes, elevation and slope were regarded as the main natural influencing factors and were transformed from coverage format to grid format within GIS. The Thiesson polygon method was used to the spatial allocation of socio-economic factors including human population, livestock numbers, mechanizing power of farming and the nearest distance from the changed pixel to the trunk stream and to main settlements, thereby the spatial relationship between land use degree change and socio-economic factor variation was analyzed. According to results of the spatial correlation, the determinants of changes in land use/cover, i. e. elevation, slope, population density change, livestock increase were extracted quantitatively in this area. At last, the spatial multi-linear regression model of land use degree change was developed as follows: △ La = 11. 037-4. 512 * eleva-tion-0. 298 * slope + 0. 292 *△ population + 2. 596 *△ livestock.展开更多
The research of land use and land cover (LUCC) is an important aspect in the global change research. The goal of this study is to find methods of extraction of LUCC’s change outlined and change type from remotely sen...The research of land use and land cover (LUCC) is an important aspect in the global change research. The goal of this study is to find methods of extraction of LUCC’s change outlined and change type from remotely sensed data. Take the country of Fengxian in Shanghai as an example, it was supposed two steps to finish extraction of LUCC information: the first step was to use different methods, which is used to outline change areas; the second step include methods of false composing of two-temporal and threshold value. Through combining two methods, a model rule is built and the LUCC product is obtained, four kinds of change type within the study area are given, and the results are obvious. Finally, the results support the application of the high resolution image and tasseled cap composition (greenness and wetness) in the specific regional too.展开更多
Problem statement: The method of non-destructive testing is needed in different aspects of geology, geomechanics and archeology, for instance: by testing the state of rock massifs in sault, kimberlites or rock shock m...Problem statement: The method of non-destructive testing is needed in different aspects of geology, geomechanics and archeology, for instance: by testing the state of rock massifs in sault, kimberlites or rock shock mines, ancient archeological objects, or mapping for locating the wells drilling. The best method for solution these problems is based on using induction multi frequency electromagnetic field with use control sources on 3D planshet system of observation. Applied methods and design: Such method was developed at the Institute of Geophysics, Ural Branch of the Russian Academy of Sciences that allows its use to solve complex geological problems for mapping and monitoring the state of the environment. Its use allows the observation system to be used in such way that, on the one hand, it achieves flexible tunable detail of observations, and on the other hand, it organizes an input database that is close to the domain of definition of the inverse problem operator in the class of layered-block models with local hierarchical inclusions. This allows using regularization methods to obtain solutions that are in the class of equivalent, close to true. The specific possibilities of its use are determined by the technical side: the power of the excitation source, the sensitivity of the receiving system. Typical results: It had been developed a new method of mapping, processing and interpretation, realized in a set of programs that allow seeing the result of the searching structure of the environment in real time (that is after receiving some results during one day, we can see the results of the geoelectrical features of the structure and the state of that part of the environment). It had been suggested a three staged conception of interpretation that can be used not only for interpretation electromagnetic induction data and dynamic seismic data. Concluding note (Practical value/implications): In the considered case, this method contributed to the study of altered forms of kimberlitic bodies. The method underwent geological verification in various geological conditions where it had been used for mapping the geoelectrical structure. This allows us to offer a method for the development of innovative technology in the search for hydrocarbons in complex geological structures. The method was used in Egypt for research ancient archeological objects, located in Alexandria.展开更多
Taking Ji’nan as a case study area,this paper aims to analyze the land use changes from late 1980s to 2010 by using remote sensing data.The geographic information systems(GIS)method and land use transfer matrix metho...Taking Ji’nan as a case study area,this paper aims to analyze the land use changes from late 1980s to 2010 by using remote sensing data.The geographic information systems(GIS)method and land use transfer matrix methods were used to calculate the temporal and spatial differences of land use change.From the analysis of the land use transfer matrix,the most significant change is the cultivated land being transferred to construction land.From late 1980s to 2010,a total of 20615 hectares of cultivated land had been converted to construction land,accounting for 11.04%of the cultivated land in all.Through the analysis of the factors of land use transition,the human dimensions that had influenced the land use changes were population factor and economy factor.展开更多
The“Grain for Green”project(GGP)was launched in 1999 on China’s Loess Plateau to reduce soil erosion,which had far-reaching impacts on the local eco-hydrological processes.In this study,we use monthly runoff depth ...The“Grain for Green”project(GGP)was launched in 1999 on China’s Loess Plateau to reduce soil erosion,which had far-reaching impacts on the local eco-hydrological processes.In this study,we use monthly runoff depth and precipitation datasets spanning 1961 to 2015 for 16 primary basins of the plateau to reveal changes in runoff generation capacity before and after the GGP.We use a Budyko-based elasticity method to calculate the runoff depth(R_(1))and runoff coefficient(C_(1))exclusively attributable to land use/cover change.Results indicate that the mean annual runoff coefficients(Co)decline by 26%—76%from the periods 1961—1999 to 2000—2015.The annual observed runoff depth(Ro)and C_(0)for 75%of basins show significant downward trends during 1961—1999;after the implementation of the GGP,both annual Ro and annual Co for over 50%of basins show upward trends.The study further finds that the increase of erosive rainfall during the period 2000-2015,whose mean increasing rate reaches 4.6 mm/year,is the main reason for the upward trends of Ro and Co.After removing the effect of precipitation variation during this period,we find that 11 out of 16 basins show decreased trends for Cj,with the downward rate between 2.4%and 6.0%per year.The reduction rate in semi-arid areas is about four times the rate in semi-humid areas.The results remind us to consider the carrying capacity of local water resources when implementing soil and water conservation measures across the Loess Plateau.展开更多
In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. Th...In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. The reconstructed surface is obtained by continuously deforming an initial surface following the Partial Differential Equation (PDE)-based diffusion model derived by a minimal volume-like variational formulation. The evolution is driven both by the distance from the data set and by the curvature analytically computed by it. The distance function is computed by implicit local interpolants defined in terms of radial basis functions. Space discretization of the PDE model is obtained by finite co-volume schemes and semi-implicit approach is used in time/scale. The use of a level set method for the numerical computation of the surface reconstruction allows us to handle complex geometry and even changing topology,without the need of user-interaction. Numerical examples demonstrate the ability of the proposed method to produce high quality reconstructions. Moreover, we show the effectiveness of the new approach to solve hole filling problems and Boolean operations between different data sets.展开更多
A seismic reflection of Line 12-B belonging to Mianwali Re-entrant was acquired and processed for 2-D interpretation. The line orients itself NNE-SSW direction. The sections have the shot points from VP-199 to VP-1044...A seismic reflection of Line 12-B belonging to Mianwali Re-entrant was acquired and processed for 2-D interpretation. The line orients itself NNE-SSW direction. The sections have the shot points from VP-199 to VP-1044. Eleven Reflectors R1, R2, R3, Base Miocene, Pinchout P1, P2, P3, P4, P5P6 (Pinchout) are marked and a basement has been marked and interpreted. All the reflectors above the basement show a downward bending at the center. The depth of each reflector was calculated by iso velocity contour map method. The depth section obtained by this method shows stratigraphic features like Pinchouts. The reflectors are then correlated with the subsurface structures and stratigraphy of the area.展开更多
In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the m...In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the matter here, we will see in part 1: about the Galaxy life cycle, where the birth and death of Galaxies discussed. Probably Universe gives guidance for the movement of Galaxies. We call this Part 1: Thinking and Reproducing Universe or Mindless Universe? (Galaxy life cycle). We see every day Sun, Stars, Galaxies etc., dissipating enormous energy in the form of radiation by the way of fusion of Hydrogen to helium. So after sometime all the Hydrogen is spent and Universe will die, is it not? … Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes in frequency and finally will convert into neutrinos (mass). Hence Dynamic Universe Model proposes another process where energy will be converted back into matter and the cycle energy to mass to energy continues, sustaining the Universe to maintain this present status for ever in this form something like a Steady state model without any expansion. This we will see in Part 2: Energy - Mass - Energy Cycle. After converting energy into mass “how various elements are formed and where they are formed?” will be next logical question. Dynamic Universe Model says that these various particles change into higher massive particles or may get bombarded into stars or planets and various elements are formed. Here we bifurcate the formation of elements into 6 processes. They are for Elementary particles and elements generated in frequency changing process, By Cosmic rays, By Small stars, By Large Stars, By Super Novae and Manmade elements By Neutron Stars. This we will discuss in Part 3: Nucleosynthesis.展开更多
Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering ...Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.展开更多
基金supported by the Central Government to Guide Local Technological Development(23ZYQH0298)the Science and Technology Project of Gansu Province(20JR10RA656,22JR5RA416)the Science and Technology Project of Wuwei City(WW2202YFS006).
文摘Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.
基金Supported by Joint Project between Bijie Science and Technology Bureau and Guizhou University of Engineering Science (Bike Lianhe Zi (Guigongcheng)[2021]03)Guizhou Provincial Key Technology R&D Program (Qiankehe[2023]General 211).
文摘Wetland ecosystems are important regulators of global climate change.Studying the spatiotemporal changes and driving mechanisms of their ecosystem service values(ESV)is beneficial for the sustainable development of wetlands.This paper uses the equivalent factor method,based on land use changes,to reveal the spatiotemporal evolution of the ecosystem service value in the Caohai National Nature Reserve(CNNR).The results show the following:①from 2000 to 2020,there was a significant decrease in the core zone s arable land area,with an increase in forest and water areas.Construction land mainly increased in the experimental area,and the grassland area showed a fluctuating change of first increasing and then decreasing;②in 2000,2010,and 2020,the ecosystem service value of the study area was 302 million,296 million,and 325 million yuan,respectively,showing a trend of fluctuating growth,with the value of wetland ecosystems playing a dominant role;③regulatory services are the main contributors to the ecosystem service value in the study area,with a contribution rate of 60%.Hydrological regulation is the ecosystem function with the highest value in wetland ecosystem services,contributing more than 35%to the ESV in all three periods;④in terms of spatial distribution,the core zone s ecosystem service value is dominant.Looking at the total ecosystem service value of the region,the core zone>the experimental area>the buffer zone.In terms of ESV per unit area,the core zone(89000 yuan/hm^(2))is significantly higher than the buffer zone(39100 yuan/hm^(2))and the experimental area(15800 yuan/hm^(2)).The study can provide a basis for research and spatial management of ecosystem services in wetland ecosystems and nature reserves.
基金Under the auspices of National Natural Science Foundation of China(No.41871216)。
文摘Land use changes have significant impacts on the carbon balance in an urban ecosystem.When there is rapid development in urbanizing regions,land use changes have a dramatic effect on vegetation carbon storage(VCS).This study investigates the impact of land use change on VCS in a period of rapid urbanization in Hangzhou,China.The results show that:1)from 2000 to 2015,land use in Hangzhou underwent huge changes,mainly reflected in decrease in cropland and wetland and the increased settlement.More than 34.58%of the land was transformed,and the land use changes are primarily characterized by a significant decrease in cropland due to the occupation by settlement.2)over the 15 years,changes in land use led to a decrease of 3.93×10^(5) t of VCS in the urban ecosystem.The large-scale transformation of cropland and wetland,which have a comparatively high carbon density,into land for settlement exerted a negative impact on VCS.3)The central city,which with the Circle-E/I/O mode,had the lowest comprehensive land use dynamic degree,leading to moderate land use change and an increase in VCS;Yuhang and Xiaoshan,which with Multicore-E/O/I mode and Fan-E/O/I modes,had a higher comprehensive land use dynamic degree,drastic changes in land use,and a decrease in VCS.This study proposes a reliable method of estimating changes in VCS,clarifies the relationship between land use change and VCS during rapid urbanization,and provides recommendations for sustainable urban development.
基金Under the auspices of the Key Knowledge-Innovation Project of the Chinese Academy of the Science(KZCX1-Y-02)andthe project of National Ninth Five-year Plan(96-B02-01).
文摘ABSTRACT: Based on the Landsat 5 and Landsat 7 TM images, the land use/cover change was detected in the upstream area of the Nenjiang River between 1995 and 2000. With the spatial analysis techniques of GIS, the maps of land use degree and its change within this period were produced. To identify the causes of changes, elevation and slope were regarded as the main natural influencing factors and were transformed from coverage format to grid format within GIS. The Thiesson polygon method was used to the spatial allocation of socio-economic factors including human population, livestock numbers, mechanizing power of farming and the nearest distance from the changed pixel to the trunk stream and to main settlements, thereby the spatial relationship between land use degree change and socio-economic factor variation was analyzed. According to results of the spatial correlation, the determinants of changes in land use/cover, i. e. elevation, slope, population density change, livestock increase were extracted quantitatively in this area. At last, the spatial multi-linear regression model of land use degree change was developed as follows: △ La = 11. 037-4. 512 * eleva-tion-0. 298 * slope + 0. 292 *△ population + 2. 596 *△ livestock.
基金Project (20010101) supported by the Ministry of Landand Resource of China
文摘The research of land use and land cover (LUCC) is an important aspect in the global change research. The goal of this study is to find methods of extraction of LUCC’s change outlined and change type from remotely sensed data. Take the country of Fengxian in Shanghai as an example, it was supposed two steps to finish extraction of LUCC information: the first step was to use different methods, which is used to outline change areas; the second step include methods of false composing of two-temporal and threshold value. Through combining two methods, a model rule is built and the LUCC product is obtained, four kinds of change type within the study area are given, and the results are obvious. Finally, the results support the application of the high resolution image and tasseled cap composition (greenness and wetness) in the specific regional too.
文摘Problem statement: The method of non-destructive testing is needed in different aspects of geology, geomechanics and archeology, for instance: by testing the state of rock massifs in sault, kimberlites or rock shock mines, ancient archeological objects, or mapping for locating the wells drilling. The best method for solution these problems is based on using induction multi frequency electromagnetic field with use control sources on 3D planshet system of observation. Applied methods and design: Such method was developed at the Institute of Geophysics, Ural Branch of the Russian Academy of Sciences that allows its use to solve complex geological problems for mapping and monitoring the state of the environment. Its use allows the observation system to be used in such way that, on the one hand, it achieves flexible tunable detail of observations, and on the other hand, it organizes an input database that is close to the domain of definition of the inverse problem operator in the class of layered-block models with local hierarchical inclusions. This allows using regularization methods to obtain solutions that are in the class of equivalent, close to true. The specific possibilities of its use are determined by the technical side: the power of the excitation source, the sensitivity of the receiving system. Typical results: It had been developed a new method of mapping, processing and interpretation, realized in a set of programs that allow seeing the result of the searching structure of the environment in real time (that is after receiving some results during one day, we can see the results of the geoelectrical features of the structure and the state of that part of the environment). It had been suggested a three staged conception of interpretation that can be used not only for interpretation electromagnetic induction data and dynamic seismic data. Concluding note (Practical value/implications): In the considered case, this method contributed to the study of altered forms of kimberlitic bodies. The method underwent geological verification in various geological conditions where it had been used for mapping the geoelectrical structure. This allows us to offer a method for the development of innovative technology in the search for hydrocarbons in complex geological structures. The method was used in Egypt for research ancient archeological objects, located in Alexandria.
基金supported by the Shandong Social Science Planning Fund Program(Grant No.20CJJJ04)。
文摘Taking Ji’nan as a case study area,this paper aims to analyze the land use changes from late 1980s to 2010 by using remote sensing data.The geographic information systems(GIS)method and land use transfer matrix methods were used to calculate the temporal and spatial differences of land use change.From the analysis of the land use transfer matrix,the most significant change is the cultivated land being transferred to construction land.From late 1980s to 2010,a total of 20615 hectares of cultivated land had been converted to construction land,accounting for 11.04%of the cultivated land in all.Through the analysis of the factors of land use transition,the human dimensions that had influenced the land use changes were population factor and economy factor.
文摘The“Grain for Green”project(GGP)was launched in 1999 on China’s Loess Plateau to reduce soil erosion,which had far-reaching impacts on the local eco-hydrological processes.In this study,we use monthly runoff depth and precipitation datasets spanning 1961 to 2015 for 16 primary basins of the plateau to reveal changes in runoff generation capacity before and after the GGP.We use a Budyko-based elasticity method to calculate the runoff depth(R_(1))and runoff coefficient(C_(1))exclusively attributable to land use/cover change.Results indicate that the mean annual runoff coefficients(Co)decline by 26%—76%from the periods 1961—1999 to 2000—2015.The annual observed runoff depth(Ro)and C_(0)for 75%of basins show significant downward trends during 1961—1999;after the implementation of the GGP,both annual Ro and annual Co for over 50%of basins show upward trends.The study further finds that the increase of erosive rainfall during the period 2000-2015,whose mean increasing rate reaches 4.6 mm/year,is the main reason for the upward trends of Ro and Co.After removing the effect of precipitation variation during this period,we find that 11 out of 16 basins show decreased trends for Cj,with the downward rate between 2.4%and 6.0%per year.The reduction rate in semi-arid areas is about four times the rate in semi-humid areas.The results remind us to consider the carrying capacity of local water resources when implementing soil and water conservation measures across the Loess Plateau.
基金supported by PRIN-MIUR-Cofin 2006,project,by"Progetti Strategici EF2006"University of Bologna,and by University of Bologna"Funds for selected research topics"
文摘In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. The reconstructed surface is obtained by continuously deforming an initial surface following the Partial Differential Equation (PDE)-based diffusion model derived by a minimal volume-like variational formulation. The evolution is driven both by the distance from the data set and by the curvature analytically computed by it. The distance function is computed by implicit local interpolants defined in terms of radial basis functions. Space discretization of the PDE model is obtained by finite co-volume schemes and semi-implicit approach is used in time/scale. The use of a level set method for the numerical computation of the surface reconstruction allows us to handle complex geometry and even changing topology,without the need of user-interaction. Numerical examples demonstrate the ability of the proposed method to produce high quality reconstructions. Moreover, we show the effectiveness of the new approach to solve hole filling problems and Boolean operations between different data sets.
文摘A seismic reflection of Line 12-B belonging to Mianwali Re-entrant was acquired and processed for 2-D interpretation. The line orients itself NNE-SSW direction. The sections have the shot points from VP-199 to VP-1044. Eleven Reflectors R1, R2, R3, Base Miocene, Pinchout P1, P2, P3, P4, P5P6 (Pinchout) are marked and a basement has been marked and interpreted. All the reflectors above the basement show a downward bending at the center. The depth of each reflector was calculated by iso velocity contour map method. The depth section obtained by this method shows stratigraphic features like Pinchouts. The reflectors are then correlated with the subsurface structures and stratigraphy of the area.
文摘In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the matter here, we will see in part 1: about the Galaxy life cycle, where the birth and death of Galaxies discussed. Probably Universe gives guidance for the movement of Galaxies. We call this Part 1: Thinking and Reproducing Universe or Mindless Universe? (Galaxy life cycle). We see every day Sun, Stars, Galaxies etc., dissipating enormous energy in the form of radiation by the way of fusion of Hydrogen to helium. So after sometime all the Hydrogen is spent and Universe will die, is it not? … Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes in frequency and finally will convert into neutrinos (mass). Hence Dynamic Universe Model proposes another process where energy will be converted back into matter and the cycle energy to mass to energy continues, sustaining the Universe to maintain this present status for ever in this form something like a Steady state model without any expansion. This we will see in Part 2: Energy - Mass - Energy Cycle. After converting energy into mass “how various elements are formed and where they are formed?” will be next logical question. Dynamic Universe Model says that these various particles change into higher massive particles or may get bombarded into stars or planets and various elements are formed. Here we bifurcate the formation of elements into 6 processes. They are for Elementary particles and elements generated in frequency changing process, By Cosmic rays, By Small stars, By Large Stars, By Super Novae and Manmade elements By Neutron Stars. This we will discuss in Part 3: Nucleosynthesis.
文摘Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.