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Spatiotemporal characteristics, patterns, and causes of land-use changes in China since the late 1980s 被引量:271
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作者 LIU Jiyuan KUANG Wenhui +13 位作者 ZHANG Zengxiang XU Xinliang QIN Yuanwei NING Jia ZHOU Wancun ZHANG Shuwen LI Rendong YAN Changzhe WU Shixin SHI Xuezheng JIANG Nan YU Dongsheng PAN Xianzhang CHI Wenfeng 《Journal of Geographical Sciences》 SCIE CSCD 2014年第2期195-210,共16页
Land-use/land-cover changes (LUCCs) have links to both human and nature inter- actions. China's Land-Use/cover Datasets (CLUDs) were updated regularly at 5-year inter- vals from the late 1980s to 2010, with stand... Land-use/land-cover changes (LUCCs) have links to both human and nature inter- actions. China's Land-Use/cover Datasets (CLUDs) were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM/ETM+ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes (LUCs) across China indicated a significant variation in spatial and temporal characteristics in the last 20 years (1990-2010). The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included (1) an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; (2) shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; (3) continuous transformation from rain-fed farmlands in northeast China to paddy fields; and (4) effective- ness of the "Grain for Green" project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change 展开更多
关键词 satellite remote sensing land-use change CHARACTERISTICS spatial pattern China
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Plant abiotic stress response and nutrient use efficiency 被引量:132
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作者 Zhizhong Gong Liming Xiong +14 位作者 Huazhong Shi Shuhua Yang Luis R.Herrera-Estrella Guohua Xu Dai-Yin Chao Jingrui Li Peng-Yun Wang Feng Qin Jigang Li Yanglin Ding Yiting Shi Yu Wang Yongqing Yang Yan Guo Jian-Kang Zhu 《Science China(Life Sciences)》 SCIE CAS CSCD 2020年第5期635-674,共40页
Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit th... Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit the stress signals within cells as well as between cells and tissues,and make appropriate adjustments in their growth and development in order to survive and reproduce.In recent years,significant progress has been made on many fronts of the stress signaling research,particularly in understanding the downstream signaling events that culminate at the activation of stress-and nutrient limitation-responsive genes,cellular ion homeostasis,and growth adjustment.However,the revelation of the early events of stress signaling,particularly the identification of primary stress sensors,still lags behind.In this review,we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies. 展开更多
关键词 abiotic stress sensing nutrient use efficiency heavy metal Ca2+signaling ROS signal transduction PHOSPHORYLATION transcription factor TRANSPORTER
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The hierarchy quorum sensing networ in Pseudomonas aeruginosa 被引量:82
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作者 Jasmine Lee Lianhui Zhang 《Protein & Cell》 SCIE CAS CSCD 2015年第1期26-41,共16页
Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradi- cate as P. aeruginosa has developed strong resistance to ... Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradi- cate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing (QS), a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacte- rial population changes but also could react to envi- ronmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics. 展开更多
关键词 quorum sensing IQS PQS LAS rhl Pseudomonas aeruginosa VIRULENCE environmental factors
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新型光纤光栅线性调谐方法 被引量:37
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作者 刘志国 张艺兵 +3 位作者 开桂云 董孝义 郑建成 李家安 《光学学报》 EI CAS CSCD 北大核心 1998年第12期1731-1734,共4页
报道了一种线性度极佳的光纤光栅波长调谐技术,调谐范围近10nm,线性拟合度达到0.9998,并首次利用材料力学原理推导了这种线性调谐的理论关系式,此种技术可望在光纤传感、光纤通信及激光技术等方面有重要应用前景。
关键词 光纤光栅 调谐 简支梁 传感
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压电类智能结构的力学行为和工程应用 被引量:20
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作者 尹林 沈亚鹏 《力学进展》 EI CSCD 北大核心 1998年第2期163-172,共10页
智能结构是近几年国际上兴起的一门多学科交叉的前沿课题.由于具有很强的工程应用前景,美、日等发达国家投入了大量的人力、物力进行这方面的开发研究.首先对智能结构的定义、组成作了简要介绍.就智能结构研究中的热点——压电类智... 智能结构是近几年国际上兴起的一门多学科交叉的前沿课题.由于具有很强的工程应用前景,美、日等发达国家投入了大量的人力、物力进行这方面的开发研究.首先对智能结构的定义、组成作了简要介绍.就智能结构研究中的热点——压电类智能结构,从其力学行为和工程应用两方面,详细论述了目前国内外的研究现状. 展开更多
关键词 智能结构 压电材料 力学分析 传感 作动
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Remote sensing of the urban heat island and its changes in Xiamen City of SE China 被引量:53
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作者 XUHan-qiu CHENBen-qing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第2期276-281,共6页
World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. ... World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island(UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band 6 of two Landsat TM/ETM\++ images of 1989 and 2000 to observe the UHI changes over 11-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen's urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index(URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu Island. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and usin 展开更多
关键词 remote sensing urban heat island urban-heat-island ratio index digital brightness model Xiamen City
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Grassland degradation in the "Three-River Headwaters" region, Qinghai Province 被引量:54
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作者 LIU Jiyuan XU Xinliang SHAO Quanqin 《Journal of Geographical Sciences》 SCIE CSCD 2008年第3期259-273,共15页
Supported by MSS images in the mid and late 1970s,TM images in the early 1990s and TM/ETM images in 2004,grassland degradation in the"Three-River Headwaters"region (TRH region)was interpreted through analysis on R... Supported by MSS images in the mid and late 1970s,TM images in the early 1990s and TM/ETM images in 2004,grassland degradation in the"Three-River Headwaters"region (TRH region)was interpreted through analysis on RS images in two time series,then the spatial and temporal characteristics of grassland degradation in the TRH region were analyzed since the 1970s.The results showed that grassland degradation in the TRH region was a continuous change process which had large affected area and long time scale,and rapidly strengthen phenomenon did not exist in the 1990s as a whole.Grassland degradation pattern in the TRH region took shape initially in the mid and late 1970s.Since the 1970s,this degradation process has taken place continuously,obviously characterizing different rules in different regions.In humid and semi-humid meadow region,grassland firstly fragmentized, then vegetation coverage decreased continuously,and finally"black-soil-patch"degraded grassland was formed.But in semi-arid and arid steppe region,the vegetation coverage decreased continuously,and finally desertification was formed.Because grassland degradation had obviously regional differences in the TRH region,it could be regionalized into 7 zones, and each zone had different characteristics in type,grade,scale and time process of grassland degradation. 展开更多
关键词 "Three-River Headwaters" region QINGHAI grassland degradation remote sensing spatial pattern temporal process
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Eco-Environmental Vulnerability Evaluation in the Yellow River Basin,China 被引量:53
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作者 WANG Si-Yuan LIU Jing-Shi YANG Cun-Jian 《Pedosphere》 SCIE CAS CSCD 2008年第2期171-182,共12页
Using remote sensing(RS)data and geographical information system(GIS),eco-environmental vulnerability and its changes were analyzed for the Yellow River Basin,China.The objective of this study was to improve our under... Using remote sensing(RS)data and geographical information system(GIS),eco-environmental vulnerability and its changes were analyzed for the Yellow River Basin,China.The objective of this study was to improve our understanding of eco-environmental changes so that a strategy of sustainable land use could be established.An environmental numerical model was developed using spatial principal component analysis(SPCA)model.The model contains twelve factors that include variables of land use,soil erosion,topography,climate,and vegetation.Using this model,synthetic eco- environmental vulnerability index(SEVI)was computed for 1990 and 2000 for the Yellow River Basin.The SEVI was classified into six levels,potential,slight,light,medium,heavy,and very heavy,following the natural breaks classification. The eco-environmental vulnerability distribution and its changes over the ten years from 1990 to 2000 were analyzed and the driving factors of eco-environmental changes were investigated.The results show that the eco-environmental vulnerability in the study area was at medium level,and the eco-environmental quality had been gradually improved on the whole.However,the eco-environmental quality had become worse over the ten years in some regions.In the study area,population growth,vegetation degradation,and governmental policies for eco-environmental protection were found to be the major factors that caused the eco-environmental changes over the ten years. 展开更多
关键词 eco-environmental vulnerability geographic information system (GIS) remote sensing (RS) spatial principal component analysis Yellow River Basin
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The clinical impact of bacterial biofilms 被引量:51
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作者 Niels Hoiby Oana Ciofu +7 位作者 Helle Krogh Johansen Zhi-jun Song Claus Moser Peter Ostrup Jenser Soren Molin Michael Givskov Tim Tolker-Nieisen Thomas Bjamsholt 《International Journal of Oral Science》 SCIE CAS CSCD 2011年第2期55-65,共11页
Bacteria survive in nature by forming biofilms on surfaces and probably most, if not all, bacteria (and fungi) are capable of forming biofilms. A biofilm is a structured consortium of bacteria embedded in a self-pro... Bacteria survive in nature by forming biofilms on surfaces and probably most, if not all, bacteria (and fungi) are capable of forming biofilms. A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and extracellular DNA. Bacterial biofilms are resistant to antibiotics, disinfectant chemicals and to phagocytosis and other components of the innate and adaptive inflammatory defense system of the body. It is known, for example, that persistence of staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infections in cystic fibrosis patients are caused by biofilm growing mucoid strains. Gradients of nutrients and oxygen exist from the top to the bottom of biofilms and the bacterial cells located in nutrient poor areas have decreased metabolic activity and increased doubling times. These more or less dormant cells are therefore responsible for some of the tolerance to antibiotics. Biofilm growth is associated with an increased level of mutations. Bacteria in biofilms communicate by means of molecules, which activates certain genes responsible for production of virulence factors and, to some extent, biofilm structure. This phenomenon is called quorum sensing and depends upon the concentration of the quorum sensing molecules in a certain niche, which depends on the number of the bacteria. Biofilms can be prevented by antibiotic prophylaxis or early aggressive antibiotic therapy and they can be treated by chronic suppressive antibiotic therapy. Promising strategies may include the use of compounds which can dissolve the biofilm matrix and quorum sensing inhibitors, which increases biofilm susceptibility to antibiotics and phagocytosis. 展开更多
关键词 bacterial biofilm biofilm infection antibiotic resistance quorum sensing
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Estimation of Net Primary Productivity of Terrestrial Vegetation in China by Remote Sensing 被引量:31
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作者 陈利军 刘高焕 冯险峰 《Acta Botanica Sinica》 CSCD 2001年第11期1191-1198,共8页
Among the many approaches for studying the net primary productivity (NPP), a new method by using remote sensing was introduced in this paper. With spectral information source (the visible band, near infrared band and ... Among the many approaches for studying the net primary productivity (NPP), a new method by using remote sensing was introduced in this paper. With spectral information source (the visible band, near infrared band and thermal infrared band) of NOAA-AVHRR, we can get the relative index and parameters, which can be used for estimating NPP of terrestrial vegetation. By means of remote sensing, the estimation of biomass and NPP is mainly based on the models of light energy utilization. In other words, the biomass and NPP can be calculated from the relation among NPP, absorbed photosynthetical active radiation (APAR) and the rate (epsilon) of transformation of APAR to organic matter, thus: NPP = ( FPAR x PAR) x [epsilon * x sigma (T) x sigma (E) x sigma (S) x (1 - Y-m) x (1 - Y-g)]. Based upon remote sensing ( RS) and geographic information system (GIS), the NPP of terrestrial vegetation in China in every ten days was calculated, and the annual NPP was integrated. The result showed that the total NPP of terrestrial vegetation in China was 6.13 x 10(9) t C . a(-1) in 1990 and the maximum NPP was 1 812.9 g C/m(2). According to this result, the spatio-temporal distribution of NPP was analyzed. Comparing to the statistical models, the RS model, using area object other than point one, can better reflect the distribution of NPP, and match the geographic distribution of vegetation in China. 展开更多
关键词 remote sensing net primary productivity absorbed photosynthetical active radiation light energy utilization BIOMASS
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Assessment of soil erosion by RUSLE model using remote sensing and GIS-A case study of Nethravathi Basin 被引量:48
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作者 B.P.Ganasri H.Ramesh 《Geoscience Frontiers》 SCIE CAS CSCD 2016年第6期953-961,共9页
Soil erosion is a serious problem arising from agricultural intensification, land degradation and other anthropogenic activities. Assessment of soil erosion is useful in planning and conservation works in a watershed ... Soil erosion is a serious problem arising from agricultural intensification, land degradation and other anthropogenic activities. Assessment of soil erosion is useful in planning and conservation works in a watershed or basin. Modelling can provide a quantitative and consistent approach to estimate soil erosion and sediment yield under a wide range of conditions. In the present study, the soil loss model, Revised Universal Soil Loss Equation (RUSLE) integrated with GIS has been used to estimate soil loss in the Nethravathi Basin located in the southwestern part of India. The Nethravathi Basin is a tropical coastal humid area having a drainage area of 3128 km2 up to the gauging station. The parameters of RUSLE model were estimated using remote sensing data and the erosion probability zones were determined using GIS. The estimated rainfall erosivity, soil erodibility, topographic and crop management factors range from 2948.16 to 4711.4 MJ/mm.ha-1hr-1/year, 0.10 to 0.44 t ha-1 -MJ-1.mm 1, 0 to 92,774 and 0 to 0.63 respectively. The results indicate that the estimated total annual potential soil loss of about 473,339 t/yr is comparable with the measured sediment of 441,870 t/yr during the water year 2002 2003. The predicted soil erosion rate due to increase in agricultural area is about 14,673.5 t/yr. The probability zone map has been derived by the weighted overlay index method indicate that the major portion of the study area comes under low probability zone and only a small portion comes under high and very high probability zone. The results can certainly aid in implementation of soil management and conservation practices to reduce the soil erosion in the Nethravathi Basin. 展开更多
关键词 Soil erosion RUSLE Remote sensing GIS Nethravathi Basin
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Current status and future trends of precision agricultural aviation technologies 被引量:46
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作者 Yubin Lan Chen Shengde Bradley K Fritz 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2017年第3期1-17,共17页
Modern technologies and information tools can be used to maximize agricultural aviation productivity allowing for precision application of agrochemical products.This paper reviews and summarizes the state-of-the-art i... Modern technologies and information tools can be used to maximize agricultural aviation productivity allowing for precision application of agrochemical products.This paper reviews and summarizes the state-of-the-art in precision agricultural aviation technology highlighting remote sensing,aerial spraying and ground verification technologies.Further,the authors forecast the future of precision agricultural aviation technology with key development directions in precision agricultural aviation technologies,such as real-time image processing,variable-rate spraying,multi-sensor data fusion and RTK differential positioning,and other supporting technologies for UAV-based aerial spraying.This review is expected to provide references for peers by summarizing the history and achievements,and encourage further development of precision agricultural aviation technologies. 展开更多
关键词 precision agricultural aviation technology remote sensing aerial spraying UAV PESTICIDE ground verification
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Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants 被引量:44
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作者 Zhaoliang Zhang Hong Liao William J.Lucas 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2014年第3期192-220,共29页
As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition... As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate (Pi) to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehen- sive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies. 展开更多
关键词 ADAPTATION crop engineering strategies hormone networks local and long-distance sensing PHOSPHATE P use efficiency stress responses systemic signaling transcriptional regulation transport systems
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Spatiotemporal patterns and characteristics of land-use change in China during 2010–2015 被引量:44
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作者 宁佳 刘纪远 +10 位作者 匡文慧 徐新良 张树文 颜长珍 李仁东 吴世新 胡云锋 杜国明 迟文峰 潘涛 宁静 《Journal of Geographical Sciences》 SCIE CSCD 2018年第5期547-562,共16页
Land use/cover change is an important theme on the impacts of human activities on the earth systems and global environmental change. National land-use changes of China during 2010–2015 were acquired by the digital in... Land use/cover change is an important theme on the impacts of human activities on the earth systems and global environmental change. National land-use changes of China during 2010–2015 were acquired by the digital interpretation method using the high-resolution remotely sensed images, e.g. the Landsat 8 OLI, GF-2 remote sensing images. The spatiotemporal characteristics of land-use changes across China during 2010–2015 were revealed by the indexes of dynamic degree model, annual land-use changes ratio etc. The results indicated that the built-up land increased by 24.6×10~3 km^2 while the cropland decreased by 4.9×10~3 km^2, and the total area of woodland and grassland decreased by 16.4×10~3 km^2. The spatial pattern of land-use changes in China during 2010–2015 was concordant with that of the period 2000–2010. Specially, new characteristics of land-use changes emerged in different regions of China in 2010–2015. The built-up land in eastern China expanded continually, and the total area of cropland decreased, both at decreasing rates. The rates of built-up land expansion and cropland shrinkage were accelerated in central China. The rates of built-up land expansion and cropland growth increased in western China, while the decreasing rate of woodland and grassland accelerated. In northeastern China, built-up land expansion slowed continually, and cropland area increased slightly accompanied by the conversions between paddy land and dry land. Besides, woodland and grassland area decreased in northeastern China. The characteristics of land-use changes in eastern China were essentially consistent with the spatial govern and control requirements of the optimal development zones and key development zones according to the Major Function-oriented Zones Planning implemented during the 12 th Five-Year Plan(2011–2015). It was a serious challenge for the central government of China to effectively protect the reasonable layout of land use types dominated with the key ecological function zones and agricultural pro 展开更多
关键词 land-use CHANGE spatial-temporal CHARACTERISTICS REMOTE sensing MAJOR Function-oriented ZONES China
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The response of lake-glacier variations to climate change in Nam Co Catchment, central Tibetan Plateau, during 1970-2000 被引量:43
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作者 WU Yanhong ZHU Liping 《Journal of Geographical Sciences》 SCIE CSCD 2008年第2期177-189,共13页
Based upon the 1970 aero-photo topographic map, and TM/ETM satellite images taken in 1991 and 2000, the authors artificially interpreted boundaries of lake and glaciers in Nam Co Catchment, and quantified lake-glacier... Based upon the 1970 aero-photo topographic map, and TM/ETM satellite images taken in 1991 and 2000, the authors artificially interpreted boundaries of lake and glaciers in Nam Co Catchment, and quantified lake-glacier area variations in different stages by "integrated method" with the support of GIS. Results show that from 1970 to 2000, lake area increased from 1942.34 km^2 to 1979.79 km^2 at a rate of 1.27 km^2/a, while glacier area decreased from 167.62 km^2 to 141.88 km^2 at a rate of 0.86 km^2/a. The increasing rate of lake in 1991-2000 was 1.76 km^2/a that was faster than 1.03 km^2/a in 1970-1991, while in the same period of time, the shrinking rates of glaciers were 0.97 km^2/a and 0.80 km^2/a respectively. Important factors, relevant to lake and glacier response to the climate, such as air temperature, precipitation, potential evapotranspiration and their values in warm and cold seasons, were discussed. The result suggests that temperature increasing is the main reason for the accelerated melting of glaciers. Lake expansion is mainly induced by the increase of the glacier melting water, increase of precipitation and obvious decrease of potential evapotranspiration. Precipitation, evaporation and their linkages with lake enlargement on regional scale need to be thoroughly studied under the background of global warming and glacier retreating. 展开更多
关键词 Tibetan Plateau Nam Co Catchment LAKE GLACIER remote sensing
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THBIP-I拟人机器人研究进展 被引量:22
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作者 刘莉 汪劲松 +2 位作者 陈恳 杨东超 赵建东 《机器人》 EI CSCD 北大核心 2002年第3期262-267,共6页
清华大学 THBIP- I拟人机器人研究项目 ,由精密仪器系、机械工程系和自动化系组成研究小组进行系统研究 ,其研究目的是发展先进机器人理论和技术 ,开发自主式拟人机器人样机 .THBIP- I机器人是具有头、手臂、躯干、腿和脚的拟人机器人 ,... 清华大学 THBIP- I拟人机器人研究项目 ,由精密仪器系、机械工程系和自动化系组成研究小组进行系统研究 ,其研究目的是发展先进机器人理论和技术 ,开发自主式拟人机器人样机 .THBIP- I机器人是具有头、手臂、躯干、腿和脚的拟人机器人 ,共 32个自由度 ,并具有视觉及语音识别等智能功能 .结构设计方面 ,由直流无刷电机、滚珠丝杠、曲柄连杆机构、谐波减速器组成 ,各驱动关节轴独立运动 .控制系统分三层 :组织层、协调层、执行层 ,分别完成任务规划、关节协调运动控制、关节伺服控制等任务 .传感系统由关节位置检测、地面反力检测、姿态检测、视觉系统、语音识别系统组成 .电源系统采用机载电池系统供电 .本文将介绍 THBIP- 展开更多
关键词 THBIP-I 拟人机器人 自由度 分布式控制 机器人学
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Spatial-Temporal Pattern and Driving Forces of Land Use Changes in Xiamen 被引量:41
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作者 QUAN Bin CHEN Jian-Fei +4 位作者 QIU Hong-Lie M. J. M. ROMKENS YANG Xiao-Qi JIANG Shi-Feng LI Bi-Cheng 《Pedosphere》 SCIE CAS CSCD 2006年第4期477-488,共12页
Using Landsat TM data of 1988, 1998 and 2001, the dynamic process of the spatial-temporal characteristics of land use changes during 13 years from 1988 to 2001 in the special economic zone of Xiamen, China was analyze... Using Landsat TM data of 1988, 1998 and 2001, the dynamic process of the spatial-temporal characteristics of land use changes during 13 years from 1988 to 2001 in the special economic zone of Xiamen, China was analyzed to improve understanding and to find the driving forces of land use change so that sustainable land utilization could be practiced. During the 13 years cropland decreased remarkably by nearly 11304.95 ha. The areas of rural-urban construction and water body increased by 10 152.24 ha and 848.94 ha, respectively. From 1988 to 2001, 52.5% of the lost cropland was converted into rural-urban industrial land. Rapid urbanization contributed to a great change in the rate of cropland land use during these years. Land-reclamation also contributed to a decrease in water body area as well as marine ecological and environmental destruction. In the study area 1) urbanization and industrialization, 2) infrastructure and agricultural intensification, 3) increased affluence of the farming community, and 4) policy factors have driven the land use changes. Possible sustainable land use measures included construction of a land management system, land planning, development of potential land resources, new technology applications, and marine ecological and environmental protection. 展开更多
关键词 driving force GIS land use change remote sensing XIAMEN
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Machine learning in geosciences and remote sensing 被引量:41
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作者 David J.Lary Amir H.Alavi +1 位作者 Amir H.Gandomi Annette L.Walker 《Geoscience Frontiers》 SCIE CAS CSCD 2016年第1期3-10,共8页
Learning incorporates a broad range of complex procedures. Machine learning(ML) is a subdivision of artificial intelligence based on the biological learning process. The ML approach deals with the design of algorith... Learning incorporates a broad range of complex procedures. Machine learning(ML) is a subdivision of artificial intelligence based on the biological learning process. The ML approach deals with the design of algorithms to learn from machine readable data. ML covers main domains such as data mining, difficultto-program applications, and software applications. It is a collection of a variety of algorithms(e.g. neural networks, support vector machines, self-organizing map, decision trees, random forests, case-based reasoning, genetic programming, etc.) that can provide multivariate, nonlinear, nonparametric regression or classification. The modeling capabilities of the ML-based methods have resulted in their extensive applications in science and engineering. Herein, the role of ML as an effective approach for solving problems in geosciences and remote sensing will be highlighted. The unique features of some of the ML techniques will be outlined with a specific attention to genetic programming paradigm. Furthermore,nonparametric regression and classification illustrative examples are presented to demonstrate the efficiency of ML for tackling the geosciences and remote sensing problems. 展开更多
关键词 Machine learning GEOSCIENCES Remote sensing Regression CLASSIFICATION
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物联网及其技术发展 被引量:41
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作者 杨震 《南京邮电大学学报(自然科学版)》 2010年第4期9-14,共6页
针对物联网这个国内外信息通信领域的新热点,介绍了其演进过程、基本概念、关键技术、标准化进程,提出一些发展物联网技术和产业的建议。
关键词 物联网 传感网 感知 标识 标准
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Remote sensing imagery in vegetation mapping: a review 被引量:42
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作者 Yichun Xie Zongyao Sha Mei Yu 《Journal of Plant Ecology》 SCIE 2008年第1期9-23,共15页
Aims Mapping vegetation through remotely sensed images involves various considerations,processes and techniques.Increasing availability of remotely sensed images due to the rapid advancement of remote sensing technolo... Aims Mapping vegetation through remotely sensed images involves various considerations,processes and techniques.Increasing availability of remotely sensed images due to the rapid advancement of remote sensing technology expands the horizon of our choices of imagery sources.Various sources of imagery are known for their differences in spectral,spatial,radioactive and temporal characteristics and thus are suitable for different purposes of vegetation mapping.Generally,it needs to develop a vegetation classification at first for classifying and mapping vegetation cover from remote sensed images either at a community level or species level.Then,correlations of the vegetation types(communities or species)within this classification system with discernible spectral characteristics of remote sensed imagery have to be identified.These spectral classes of the imagery are finally translated into the vegetation types in the image interpretation process,which is also called image processing.This paper presents an overview of how to use remote sensing imagery to classify and map vegetation cover.Methods Specifically,this paper focuses on the comparisons of popular remote sensing sensors,commonly adopted image processing methods and prevailing classification accuracy assessments.Important findings The basic concepts,available imagery sources and classification techniques of remote sensing imagery related to vegetation mapping were introduced,analyzed and compared.The advantages and limitations of using remote sensing imagery for vegetation cover mapping were provided to iterate the importance of thorough understanding of the related concepts and careful design of the technical procedures,which can be utilized to study vegetation cover from remote sensed images. 展开更多
关键词 vegetation mapping remote sensing sensors image processing image classification
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