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Monitoring Land Use Dynamics in Chanthaburi Province of Thailand Using Digital Remotely Sensed Images 被引量:12
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作者 SHENRUNPING I.KHEORUENROMNE 《Pedosphere》 SCIE CAS CSCD 2003年第2期157-164,共8页
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
关键词 image classification land use dynamics remote sensing tropical area
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Land Use and Land Cover Dynamics in the Urban Watershed of Kimemi River (Butembo/D.R.C) 被引量:2
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作者 Jonathan Ahadi Mahamba Gloire Kayitoghera Mulondi +1 位作者 Moïse Musubao Kapiri Walere Muhindo Sahani 《Journal of Geoscience and Environment Protection》 2022年第6期204-219,共16页
Changes in land use and land cover (LULC) influence hydrological processes in a watershed. This study analyses the dynamics of LULC in the Kimemi watershed from 1987 to 2021. GIS and remote sensing tools as well as la... Changes in land use and land cover (LULC) influence hydrological processes in a watershed. This study analyses the dynamics of LULC in the Kimemi watershed from 1987 to 2021. GIS and remote sensing tools as well as landscape pattern analysis were used to achieve this purpose. The results reveal that the LULC change is globally marked by an increase in the bare land and building at the expense of the low vegetation (grassland). Between 1987 and 2011, the bare land and buildings (Tg = 61.33%) and the woodland (Tg = 34.2%) classes increased, whereas the grassland class decreased (Tg = -39.5%). On the other hand, between 2011 and 2015, the bare land and building class still increased (Tg = 29.9%) while that of grassland and woodland decreased with Tg = -37.3% and Tg = -4.9%, respectively. Finally, the dynamics observed from 2015 to 2021 is marked by small changes between classes with Tg values of 2.1%, 1.9% and -8.9%, respectively, for the bare land and building, grassland and woodland classes, respectively. The main spatial transformation processes observed are creation and dissection for the bare land and building class, and the grassland class respectively. In particular, the woodland class underwent the creation process between 1987 and 2011 before undergoing attrition (2011-2015-2021). Reduced vegetated areas give rise to new planning decisions to mitigate the hydrological risks that could result from this situation. 展开更多
关键词 Land use and Land Cover dynamics WATERSHED Kimemi River Butembo
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International Conference on Land Use / Cover Change Dynamics
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《Journal of Geographical Sciences》 SCIE CSCD 2001年第1期121-,共1页
Organized by: Beijing Normal University, National Natural Science Foundation of China Hosted by: Institute of Resources Science, Beijing Normal UniversityKey Laboratory of Environmental Change and Natural Disaster, Mi... Organized by: Beijing Normal University, National Natural Science Foundation of China Hosted by: Institute of Resources Science, Beijing Normal UniversityKey Laboratory of Environmental Change and Natural Disaster, Ministry of Education of ChinaTopics:1) Detecting and monitoring LUCC2) Temporal-spatial characteristics in LUCC3) Driving model for LUCC4) Forecasting and modeling LUCC 5) Phenological and biochemical response on LUCC6) Regional LUCC and microclimate 7) LUCC in the context of global change8) Impact of global change on the sustainable land-use modelingAbstract submission: The official language of this conference is English. We invite papers written in English and an abstract of less than one page of standard A4 size to the Conference Secretariat by Apr 15, 2001. Registration Fee: 280 US$ (300 US$ after July 15, 2001)Add:No. 19, Xinjiekouwai Street, 100875, Institute of Resources Science, Beijing Normal University, Beijing, ChinaTel:86-10-62207656 or 62209024 Fax:010-62208178http:// 202.112.93.50/LUCCD2001/index.htmlE-mail: Pwang@bnu.edu.cn Cyh@bnu.edu. 展开更多
关键词 LUCCD’2001 First Circular Announcement International Conference on Land use/Cover Change dynamics
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Continuous Dynamic Rotation Measurements Using a Compact Cold Atom Gyroscope 被引量:12
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作者 姚战伟 鲁思滨 +4 位作者 李润兵 王锴 曹雷 王谨 詹明生 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第8期41-44,共4页
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
关键词 of on as is in Continuous dynamic Rotation Measurements Using a Compact Cold Atom Gyroscope
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Land use and landscape pattern change: a linkage to the construction of the Qinghai-Xizang Highway 被引量:9
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作者 YAN Jianzhong, ZHANG Yili, LIU Linshan, LIU Yanhua2, ZHENG Du (1. Inst. of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China 2. The Ministry of Science and Technology, Beijing 100101, China 3. College of Resources and Enviro 《Journal of Geographical Sciences》 SCIE CSCD 2002年第3期253-265,共13页
Based on digital land use data from 1995 to 2000 and road data, the land use and landscape changes of Golmud, Qumaleb and Zhidoi are studied on a macro-scale. Land use and landscape changes in highway buffer zones and... Based on digital land use data from 1995 to 2000 and road data, the land use and landscape changes of Golmud, Qumaleb and Zhidoi are studied on a macro-scale. Land use and landscape changes in highway buffer zones and city expansion are special subjects. A new formula is used to define the exact degree of dynamic land use. To adequately define land use and landscape pattern changes, the buffer zones, illustrating the changes at different distances from the road, are recognized with ArcGIS 8.1 software. Prominent changes took place in land use and landscape patterns from 1995 to 2000, and the area of built-up land increased by 323.8%. The comprehensive degree of dynamic land use is 2.25, and the degree of dynamic land use of built-up land is the highest, followed by cultivated land. Woodland has the lowest value. The used degree index of land resources declined by 38.8 from 1995 to 2000. Landscape changed dramatically which influenced ecological processes immensely. Different from the corridor effect of other traffic routes, the corridor effect of this section of road is not obvious and its “point” radiation effect can be easily seen. The expanding range of Golmud City is confined to a 3 km buffer, while for Wudaoliang, it is 1 km. No land use change happened in the Nanshankou buffer. 展开更多
关键词 land use change comprehensive index of the degree of land use diagnostic index of landscape degree of dynamic land use Qinghai-Xizang Highway
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Impacts of Transportation Arteries on Land Use Patterns in Urbanrural Fringe: A Comparative Gradient Analysis of Qixia District, Nanjing City, China 被引量:4
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作者 ZHANG Runsen PU Lijie ZHU Ming 《Chinese Geographical Science》 SCIE CSCD 2013年第3期378-388,共11页
Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infras... Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infrastructure on land use change is necessary for evaluating the role of transportation development in the process of land use and land cover change in the urban-rural fringe. Taking Qixia District of Nanjing City, Jiangsu Province, China as a typical urban-rural fringe area, this paper analyzes the patterns and charac- teristics of land use change along three major transportation arteries using land use data from 2000 and 2008. We examine the spatial differentiation and gradient of land use pattern around railway, expressway, and highway corridors to investigate whether land use change in the urban-rural fringe is related to distance from transportation arteries and to clarify the varying impacts of different forms of transport infrastructure on land use patterns. We find that construction land generally tends to be located close to major transportation arteries, and that railways have the most obvious influence on land use change in the urban-rural fringe, while the impact of expressways was not significant. We conclude that there exists a causal relationship between the presence of transportation arteries and land use change in the urban-rural fringe, but this relationship varies across different types of linear transnort infrastrncnlre. 展开更多
关键词 land use change transportation arteries gradient analysis land use dynamic degree urban-rural fringe
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ANALYSIS ON SPATIAL DIFFERENCE OF LAND USECHANGE BASED ON PHYSICAL AND CULTURALLANDSCAPE ATTRIBUTES──A Case Study at Mongolian AutonomousCounty of Qian Gorlos, Jilin Province 被引量:3
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作者 HUANG Fang, LIU Xiang-nan, XU Hong-mei, ZHANG Shu-wen, ZHANG Yang-zhen (Changchun Institute of Geography, the Chinese Academy of Sciences, Changchun 130021, P. R. China School of Urban and Environmental Science, Northeast Normal University, Changchun 13 《Chinese Geographical Science》 SCIE CSCD 2001年第1期50-56,共7页
Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-tempor... Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-temporal pattern of land use change. There are four physical geographical regions in Mongolian Autonomou County of Qian Gorlos of Jilin Province. Based on spatial analysis and statistical analysis, we conclude that the primary pattern of land use and the tendency of land use changes are all different in four physical geographical regions. During 1987 – 1996, the dominant land use change processes were from grassland or forest to arableland, from unused land to paddy and grassland to unused land. Though land use change is mainly affected by social and economic condition in short period, the composite characters of physical geographical elements controls land use dynamic process. The relationship between land use dynamic process and the character of physical geographical units differ in different regions. Possible human impacts on land use change are explored with application of buffer areas of series distance along main roads and radius around main settlements. A few models are built to describe the relationship between land use spatial change rates and distance to road and settlements. According to our result, the relationship with the proximity to roads was a negative liner function, with the change rate decreasing rapidly when moving away from roads. Within a distance of less 7.5km from main traffic lines, land use changes occur red more. The bulk of grassland was apt to be opened up for cultivation around the settlements and the transformation from dryland to paddy occurred within the distance of 1km away from settlements. 展开更多
关键词 land use change physical geographic region land use dynamic process effective coefficient cultural landscape variable
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All-Atom Direct Folding Simulation for Proteins Using the Accelerated Molecular Dynamics in Implicit Solvent Model 被引量:1
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作者 李宗超 段莉莉 +1 位作者 冯国强 张庆刚 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第11期169-172,共4页
We report the results of protein folding (219M, C34, N36, 2KES, 2KHK) by the method of accelerated molecular dynamics (aMD) at room temperature with the implicit solvent model. Starting from the linear structures,... We report the results of protein folding (219M, C34, N36, 2KES, 2KHK) by the method of accelerated molecular dynamics (aMD) at room temperature with the implicit solvent model. Starting from the linear structures, these proteins successfully fold to the native structure in a lO0-ns aMD simulation. In contrast, they are failed under the traditional MD simulation in the same simulation time. Then we find that the lowest root mean square deviations of helix structures from the native structures are 0.36 A, 0.63 A, 0.52 A, 1.1 A and 0.78 A. What is more, native contacts, cluster and free energy analyses show that the results of the aMD method are in accordance with the experiment very well. All analyses show that the aMD can accelerate the simulation process, thus we may apply it to the field of computer aided drug designs. 展开更多
关键词 KES MD KHK All-Atom Direct Folding Simulation for Proteins Using the Accelerated Molecular dynamics in Implicit Solvent Model
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Land use/land cover change responses to ecological water conveyance in the lower reaches of Tarim River,China
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作者 WANG Shanshan ZHOU Kefa +2 位作者 ZUO Qiting WANG Jinlin WANG Wei 《Journal of Arid Land》 SCIE CSCD 2021年第12期1274-1286,共13页
The Tarim River is the longest inland river in China and is considered as an important river to protect the oasis economy and environment of the Tarim Basin.However,excessive exploitation and over-utilization of natur... The Tarim River is the longest inland river in China and is considered as an important river to protect the oasis economy and environment of the Tarim Basin.However,excessive exploitation and over-utilization of natural resources,particularly water resources,have triggered a series of ecological and environmental problems,such as the reduction in the volume of water in the main river,deterioration of water quality,drying up of downstream rivers,degradation of vegetation,and land desertification.In this study,the land use/land cover change(LUCC)responses to ecological water conveyance in the lower reaches of the Tarim River were investigated using ENVI(Environment for Visualizing Images)and GIS(Geographic Information System)data analysis software for the period of 1990-2018.Multi-temporal remote sensing images and ecological water conveyance data from 1990 to 2018 were used.The results indicate that LUCC covered an area of 2644.34 km^(2) during this period,accounting for 15.79%of the total study area.From 1990 to 2018,wetland,farmland,forestland,and artificial surfaces increased by 533.42 km^(2)(216.77%),446.68 km^(2)(123.66%),284.55 km^(2)(5.67%),and 57.51 km^(2)(217.96%),respectively,whereas areas covered by grassland and other land use/land cover types,such as Gobi,bare soil,and deserts,decreased by 103.34 km2(14.31%)and 1218.83 km2(11.75%),respectively.Vegetation area decreased first and then increased,with the order of 2010<2000<1990<2018.LUCC in the overflow and stagnant areas in the lower reaches of the Tarim River was mainly characterized by fragmentation,irregularity,and complexity.By analyzing the LUCC responses to 19 rounds of ecological water conveyance in the lower reaches of the Tarim River from 2000 to the end of 2018,we proposed guidelines for the rational development and utilization of water and soil resources and formulation of strategies for the sustainable development of the lower reaches of the Tarim River.This study provides scientific guidance for optimal scheduling of water resources in the region. 展开更多
关键词 land use/land cover change(LUCC) remote sensing land use dynamic index ecological water conveyance Tarim River
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Imaging Ultrafast Plasmon Dynamics within a Complex Dolmen Nanostructure Using Photoemission Electron Microscopy
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作者 秦将 郎鹏 +5 位作者 季博宇 N.K.Alemayehu 陶海岩 高勋 郝作强 林景全 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第11期82-86,共5页
We report direct nanoscale imaging of ultrafast plasmon in a gold dolmen nanostructure excited with the 7is laser pulses by combining the interferometric time-resolved technology with the three-photon photoemission el... We report direct nanoscale imaging of ultrafast plasmon in a gold dolmen nanostructure excited with the 7is laser pulses by combining the interferometric time-resolved technology with the three-photon photoemission electron microscopy (PEEM). The interferometric time-resolved traces show that the plasmon mode beating pattern appears at the ends of the dimer slabs in the dolmen nanostructure as a result of coherent superposition of multiple localized surface plasmon modes induced by broad bandwidth of the ultrafast laser pulses. The PEEM measurement further discloses that in-phase of the oscillation field of two neighbor defects are surprisingly observed, which is attributed to the plasmon coupling between them. Furthermore, the control of the temporal delay between the pump and probe laser pluses could be utilized for manipulation of the near-field distribution. These findings deepen our understanding of ultrafast plasmon dynamics in a complex nanosystem. 展开更多
关键词 of on as in Imaging Ultrafast Plasmon dynamics within a Complex Dolmen Nanostructure Using Photoemission Electron Microscopy that ITR
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Probing of Ultrafast Plasmon Dynamics on Gold Bowtie Nanostructure Using Photoemission Electron Microscopy
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作者 秦将 季博宇 +1 位作者 郝作强 林景全 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第6期61-65,共5页
We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon ... We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon photoemission electron microscopy. Different photoemission patterns induced by the plasmon effect are observed when the bowties are excited by s- and p-polarized femtosecond laser pulses. A series of images of the evolution of local surface plasmon modes on different tips of the bowtie are obtained by the time-resolved three-photon photoemission electron microscopy, and the result discloses that plasmon excitation is dominated by the interfer- ence of the pump and probe pulses within the first 13 fs of the delay time, and thereafter the individual plasmon starts to oscillate on its own characteristic resonant frequencies. 展开更多
关键词 Probing of Ultrafast Plasmon dynamics on Gold Bowtie Nanostructure Using Photoemission Electron Microscopy LSP
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Analysis of the dynamics of land use change and its prediction based on the integration of remotely sensed data and CA-Markov model,in the upstream Citarum Watershed,West Java,Indonesia 被引量:3
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作者 Fajar Yulianto Taufik Maulana Muhammad Rokhis Khomarudin 《International Journal of Digital Earth》 SCIE EI 2019年第10期1151-1176,共26页
In this research,the integration of remotely sensed data and Cellular Automata-Markov model(CA-Markov)have been used to analyze the dynamics of land use change and its prediction for the next year.Training phase for t... In this research,the integration of remotely sensed data and Cellular Automata-Markov model(CA-Markov)have been used to analyze the dynamics of land use change and its prediction for the next year.Training phase for the CA-Markov model has been created based on the input pair of land use,which is the result of land use mapping using Maximum Likelihood(ML)algorithm.Three-map comparison has been used to evaluate process accuracy assessment of the training phase for the CA-Markov model.Furthermore,the simulation phase for the CAMarkov model can be used to predict land use map for the next year.The analyze of the dynamics of land use change and its prediction during the period 1990 to 2050 can be obtained that the land serves as a water absorbent surfaces such as primary forest,secondary forest and the mixed garden area continued to decline.Meanwhile,on build land area that can lead to reduced surface water absorbing tends to increase from year to year.The results of this research can be used as input for the next research,which aims to determine the impact of land use changes in hydrological conditions against flooding in the research area. 展开更多
关键词 Multi-temporal remotely sensed data CA-Markov model dynamics land use change
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Geospatial analysis of forest fragmentation in Uttara Kannada District, India 被引量:1
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作者 Ramachandra T V Bharath Setturu Subash Chandran 《Forest Ecosystems》 SCIE CSCD 2016年第3期206-220,共15页
Background: Landscapes consist of heterogeneous interacting dynamic elements with complex ecological, economic and cultural attributes. These complex interactions help in the sustenance of natural resources through b... Background: Landscapes consist of heterogeneous interacting dynamic elements with complex ecological, economic and cultural attributes. These complex interactions help in the sustenance of natural resources through bio-geochemical and hydrological cycling. The ecosystem functions are altered with changes in the landscape structure, Fragmentation of large contiguous forests to small and isolated forest patches either by natural phenomena or anthropogenic activities leads to drastic changes in forest patch sizes, shape, connectivity and internal heterogeneity, which restrict the movement leading to inbreeding among Meta populations with extirpation of species. Methods: Landscape dynamics are assessed through land use analysis by way of remote sensing data acquired at different time periods. Forest fragmentation is assessed at the pixel level through computation of two indicators, i.e., Pf (the ratio of pixels that are forested to the total non-water pixels in the window) and P~ (the proportion of all adjacent (cardinal directions only) pixel pairs that include at least one forest pixel, for which both pixels are forested). Results: Uttara Kannada District has the distinction of having the highest forest cover in Karnataka State, India. This region has been experiencing changes in its forest cover and consequent alterations in functional abilities of its ecosystem. Temporal land use analyses show the trend of deforestation, evident from the reduction of evergreen - semi evergreen forest cover from 57.31% (1979) to 32.08 % (2013) Forest fragmentation at the landscape level shows a decline of interior forests 64.42 % (1979) to 25.62 % (20] 3) and transition of non-forest categories such as crop land, plantations and built-up areas, amounting now to 47.29 %. PCA prioritized geophysical and socio variables responsible for changes in the landscape structure at local levels. Conclusion: Terrestrial forest ecosystems in Uttara Kannada District of Central Western Ghats have been experiencing threats due to deforestation with land use changes and fragmentation of contiguous forests, as is evident from the decline of interior forests and consequent increases in patch, transitional, edge and perforated forests. Interior or intact forest cover in this ecologically fragile region is now 25.62 %. Considering the accelerating rates of forest fragmentation in recent times, the focus should be on reforestation and regeneration of natural vegetation to sustain food and water security and the livelihood of local populations. This requires innovation with holistic approaches in the management of forests by involving all local stakeholders to minimize the encroachment of forests, and improvements in regeneration. 展开更多
关键词 Land use dynamics Forest fraqmentation Interior forests BIODIVERSITY Geophysical variables
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Integration of Remote Sensing and GIS in Studying Land Cover Trends and Conditions in the Middle Ziz Oasis,Morocco
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作者 Ali Essahlaoui Abba Mohamed +2 位作者 Eddahby Lhou Faouzi Mohamed Larabi Abdelkader 《International Journal of Geosciences》 2013年第7期1018-1023,共6页
A better understanding of the changing patterns of land use and vegetation cover is a major concern for countries whose ecosystems are under severe degradation. Indeed, the dynamics of land have direct implications on... A better understanding of the changing patterns of land use and vegetation cover is a major concern for countries whose ecosystems are under severe degradation. Indeed, the dynamics of land have direct implications on the availability of natural resources. The palm grove, of oases of Errachidia region, plays an important role in the environmental, social and economic of this region. This research was conducted in the Ziz middle, which is affected by changes in the conditions and composition of land cover change. The application of remote sensing, geographic information systems and satellite imagery analysis with multi-temporal and spatial land use provides, for territorial managers, data updated and improved and a synopsis for effective management of natural resources. This research explores the possibility of identifying, monitoring and mapping land use change and land use on the dynamics of the palm grove in the past 40 years. Satellite images used are Landsat images and multi-temporal dates (MSS (1972), TM (1987), ETM + (2001, 2006 and 2011). These images were georeferenced and radiometrically corrected. In our study, the use of vegetation indices NDVI, SAVI and MASAVI, highlight the magnitude of changes in vegetation cover between 1972 and 2011. A regressive pronounced canopy is generally recognized in the Middle Ziz. This decline is explained by the combined effect of anthropic action (urbanization) and climatic conditions. 展开更多
关键词 Morocco Remote Sensing GIS Ziz Watershed dynamic of Land use NDVI
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PROTEIN CHARACTERIZATION USING DYNAMIC AND STATIC LIGHT SCATTERING 被引量:2
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作者 Jeffrey Yang Kevin Mattison 《China Particuology》 SCIE EI CAS CSCD 2003年第5期219-222,共4页
关键词 IS on of for PROTEIN CHARACTERIZATION USING dynamic AND STATIC LIGHT SCATTERING SLS NANO in from with that
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Probing the fractional topological charge of a vortex light beam by using dynamic angular double slits 被引量:7
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作者 Jing Zhu Pei Zhang +5 位作者 Dongzhi Fu Dongxu Chen Ruifeng Liu Yingnan Zhou Hong Gao Fuli Li 《Photonics Research》 SCIE EI 2016年第5期187-190,共4页
Vortex beams with fractional topological charge(FTC) have many special characteristics and novel applications.However, one of the obstacles for their application is the difficulty of precisely determining the FTC of f... Vortex beams with fractional topological charge(FTC) have many special characteristics and novel applications.However, one of the obstacles for their application is the difficulty of precisely determining the FTC of fractional vortex beams. We find that when a vortex beam with an FTC illuminates a dynamic angular double slit(ADS), the far-field interference patterns that include the information of the FTC of the beam at the angular bisector direction of the ADS vary periodically. Based on this property, a simple dynamic ADS device and data fitting method can be used to precisely measure the FTC of a vortex light beam with an error of less than 5%. 展开更多
关键词 Probing the fractional topological charge of a vortex light beam by using dynamic angular double slits
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Study of photoexcited-carrier dynamics in GaAs photoconductive switches using dynamic terahertz emission microscopy 被引量:1
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作者 Hironaru Murakami Shogo Fujiwara +1 位作者 Iwao Kawayama Masayoshi Tonouchi 《Photonics Research》 SCIE EI 2016年第3期9-15,共7页
We propose dynamic terahertz(THz) emission microscopy(DTEM) to visualize temporal–spatial dynamics of photoexcited carriers in electronic materials. DTEM utilizes THz pulses emitted from a sample by probe pulses irra... We propose dynamic terahertz(THz) emission microscopy(DTEM) to visualize temporal–spatial dynamics of photoexcited carriers in electronic materials. DTEM utilizes THz pulses emitted from a sample by probe pulses irradiated after pump pulse irradiation to perform time-resolved two-dimensional mapping of the THz pulse emission, reflecting various carrier dynamics. Using this microscopy, we investigated carrier dynamics in the gap region of low-temperature-grown Ga As and semi-insulating Ga As photoconductive switches of the identical-dipole type. The observed DTEM images are well explained by the change in the electric potential distribution between the electrodes caused by the screening effect of the photoexcited electron-hole pairs. 展开更多
关键词 GA Study of photoexcited-carrier dynamics in GaAs photoconductive switches using dynamic terahertz emission microscopy As THZ
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Assessment of land use change and its effect on soil carbon stock using multitemporal satellite data in semiarid region of Rajasthan, India 被引量:2
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作者 Garima Sharma L.K.Sharma K.C.Sharma 《Ecological Processes》 SCIE EI 2019年第1期513-529,共17页
Background:Land use change plays a vital role in global carbon dynamics.Understanding land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing c... Background:Land use change plays a vital role in global carbon dynamics.Understanding land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing carbon emission.Therefore,the objective of our study was to determine land use change and to assess its effect on soil carbon stock in semi-arid part of Rajasthan,India.Landsat temporal satellite data of Pushkar valley region of Rajasthan acquired on 1993,2003,and 2014 were analyzed to assess land use change.Internal trading of land use was depicted throughmatrices.Soil organic carbon(SOC)stock was calculated for soil to a depth of 30 cm in each land use type in 2014 using field data collection.The SOC stock for previous years was estimated using stock change factor.The effect of land use change on SOC stock was determined by calculating change in SOC stock(t/ha)by deducting the base-year SOC stock from the final year stock of a particular land use conversion.Results:The total area under agricultural lands was increased by 32.14%while that under forest was decreased by 23.14%during the time period of 1993–2014.Overall land use change shows that in both the periods(1993–2003 and 2003–2014),7%of forest area was converted to agricultural land and about 15%changes occurred among agricultural land.In 1993–2003,changes among agricultural land led to maximum loss of soil carbon,i.e.,4.88 Mt C and during 2003–2014,conversion of forest to agricultural land led to loss in 3.16 Mt C.Conclusion:There was a continuous decrease in forest area and increase in cultivated area in each time period.Land use change led to alteration in carbon equity in soil due to change or loss in vegetation.Overall,we can conclude that the internal trading of land use area during the 10-year period(1993–2003)led to net loss of SOC stock by 8.29 Mt C.Similarly,land use change during 11-year period(2003–2014)caused net loss of SOC by 2.76 Mt C.Efforts should be made to implement proper land use management practices to enhance the SOC content. 展开更多
关键词 Multitemporal satellite data Land use change dynamics Internal trading of land use SOC stock Stock change factor Change in SOC pool Land use management
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Impact of Wavelength-Routed Network Physical Topology on Blocking Probability Using a Dynamic Traffic Growth Model
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作者 Roger Lao Robert Killey 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期773-774,共2页
We investigate the impact of network topology on blocking probability in wavelength-routed networks using a dynamic traffic growth model. The dependence of blocking on different physical parameters is assessed.
关键词 of BE AS Impact of Wavelength-Routed Network Physical Topology on Blocking Probability Using a dynamic Traffic Growth Model were on
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Dynamic Changes of the Bush Encroachment in Low Altitude Area of Ethiopia
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作者 XING Yuanyuan WANG Yongdong +4 位作者 YOU Yuan SONG Qin HARE Malicha Loje JORRO Zinabu Bora JIRMA Guyo Huka 《Journal of Resources and Ecology》 CSCD 2018年第3期281-289,共9页
Bush encroachment is widely distributed in arid and semi-arid regions, and it has a serious impact on livestock production, especially in Africa where livestock is a primary source for the livelihoods of many people. ... Bush encroachment is widely distributed in arid and semi-arid regions, and it has a serious impact on livestock production, especially in Africa where livestock is a primary source for the livelihoods of many people. In this study, methods of supervised classification and decision tree classification, and indexes of a land use change significance index(Ci) and a single land use dynamic degree, were applied to remote sensing imagery of Ethiopia for 1986–2016. The results show the dynamic characteristics of grassland bush encroachment in low altitude areas(pastures 1500 m above sea level) of Ethiopia in the 30 year period studied. The results revealed several interesting features of this phenomenon.(1) The area of bush encroachment showed an increasing trend, with a maximum of 3.74×10^3 km^2 in 2003, which represented 68.97% of the total area, and declined slightly from 2003~2016.(2) Among classification types, the area of severe shrub grassland was the largest, accounting for 28.36–49.10% of the total area, while the area of moderate bush encroachment accounted for 9.77–16.68%, and slight bush encroachment accounted for 5.52–7.57%.(3) The expansion rate of shrubby grassland was 0.74% for the 30 year period, while the average annual expansion rate was 2.16% for the 8 years from 1995–2003.(4) Forest land and grassland were the two main land use types of shrub grassland transformation in low altitude areas and bush encroachment changed large amounts of forest land into grassland due to shrub grassland management. The results of this study provide basic data for revealing the impacts of development processes on subsequent bush encroachment and can inform better management for the sustainable development of grasslands in low altitude systems. 展开更多
关键词 bush encroachment single land use dynamic degree land use change significance index low altitude areas of Ethiopia
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