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Spatial-temporal Evolution and Determinants of the Belt and Road Initiative: A Maximum Entropy Gravity Model Approach 被引量:8
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作者 HUANG Qinshi ZHU Xigang +3 位作者 LIU Chunhui WU Wei LIU Fengbao ZHANG Xinyi 《Chinese Geographical Science》 SCIE CSCD 2020年第5期839-854,共16页
The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis... The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus. 展开更多
关键词 spatial interaction model the Belt and Road Initiative(BRI) Maximum Entropy(MaxEnt)gravity model spatial pattern China
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Spatiotemporal variation and influencing factors of desertification sensitivity on the Qinghai-Xizang Plateau,China
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作者 PAN Meihui CHEN Qing +2 位作者 LI Chenlu LI Na GONG Yifu 《Journal of Arid Land》 2025年第1期58-73,共16页
Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomi... Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomic development.In this study,the desertification sensitivity index(DSI)model was established by integrating the spatial distance model and environmentally sensitive area index evaluation method,and then the model was used to quantitatively analyze the spatial and temporal characteristics of desertification sensitivity of the Qinghai-Xizang Plateau from 1990 to 2020.The results revealed that:(1)a general increasing tendency from southeast to northwest was identified in the spatial distribution of desertification sensitivity.The low-sensitivity areas were mostly concentrated in the Hengduan and Nyaingqêntanglha mountains and surrounding forest and meadow areas.The high-sensitivity areas were located mainly in the Kunlun and Altun mountains and surrounding decertified areas.The center of gravity of all types of desertification-sensitive areas moved to the northwest,and the desertification sensitivity showed a decreasing trend as a whole;(2)the area of highly sensitive desertification areas decreased by 8.37%,with extreme sensitivity being the largest change among the sensitivity types.The desertification sensitivity transfer was characterized by a greater shift to lower sensitivity levels(24.56%)than to higher levels(2.03%),which demonstrated a declining trend;(3)since 1990,the change in desertification sensitivity has been dominated by the stabilizing type Ⅰ(29.30%),with the area of continuously increasing desertification sensitivity accounting for only 1.10%,indicating that the management of desertification has achieved positive results in recent years;and(4)natural factors have had a more significant impact on desertification sensitivity on the Xizang Plateau,whereas socioeconomic factors affected only localized areas.The main factors influencing desertification sensitivity were vegetation drought tolerance and aridity index.Studying spatiotemporal variations in desertification sensitivity and its influencing factors can provide a scientific foundation for developing strategies to control desertification on the Qinghai-Xizang Plateau.Dividing different desertification-sensitive areas on the basis of these patterns of change can facilitate the formulation of more targeted management and protection measures,contributing to ecological construction and sustainable economic development in the area. 展开更多
关键词 desertification sensitivity geodetector gravity center transfer model spatiotemporal change Qinghai-Xizang Plateau
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Uncertainty analysis of ship model vertical center of gravity and transverse moment of inertia test 被引量:1
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作者 史圣哲 郑亚雄 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2015年第1期41-46,共6页
The usability of test results of ship model vertical center of gravity and transverse moment of inertia is generally depends on its uncertainty. Referring to the guidelines for uncertainty analysis in examination of l... The usability of test results of ship model vertical center of gravity and transverse moment of inertia is generally depends on its uncertainty. Referring to the guidelines for uncertainty analysis in examination of liquid dynamic recommended by International Towing Tank Conference ( ITTC), the results were analyzed, bias limits and precision limits were calculated and total uncertainty was estimated. The total uncertainty of six tests on ship model vertical center of gravity is is 0. 16% of the mean value, and the total uncertainty of six tests on ship model transverse moment of inertia is 5.66% of the mean value. The test results show that the total uncertainty of both the multiple tests and the single test is from the precision limits of ship model vertical center of gravity and transverse moment of inertia tests. Thus, the improved measurement system stability can enormously decrease the total uncertainty of multiple tests and the single test. 展开更多
关键词 ship model test vertical center of gravity transverse moment of inertia uncertainty analysis
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Analysis and Study on Spatial Gravity Center of PM_(2.5) and Population Scale
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作者 Chaoqun LIU 《Meteorological and Environmental Research》 CAS 2023年第5期11-13,共3页
With the rapid development of urbanization construction in China,population and industries are rapidly gathering in cities,bringing about economic development and also causing a large number of environmental problems,... With the rapid development of urbanization construction in China,population and industries are rapidly gathering in cities,bringing about economic development and also causing a large number of environmental problems,among which PM_(2.5) is the most concerned.In this paper,a spatial gravity center model was used to systematically analyze the spatiotemporal distribution characteristics of PM_(2.5) and population scale in China from 1999 to 2016.Conclusions were as below:(1)there were significant regional differences in PM_(2.5) pollution from 1999 to 2016,characterized by a spatial distribution of"high in the north and low in the south,and high in the inland and low in the coastal areas".(2)Nationwide,there was a significant spatial mismatch between the gravity center of PM_(2.5) pollution and the gravity center of population scale,with the two centers showing a trend of reverse dislocation development. 展开更多
关键词 PM_(2.5) Population scale gravity center model spatial mismatch
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Spatial and temporal change patterns of net primary productivity and its response to climate change in the Qinghai–Tibet Plateau of China from 2000 to 2015 被引量:18
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作者 GUO Bing ZANG Wenqian +8 位作者 YANG Fei HAN Baomin CHEN Shuting LIU Yue YANG Xiao HE Tianli CHEN Xi LIU Chunting GONG Rui 《Journal of Arid Land》 SCIE CSCD 2020年第1期1-17,共17页
The vegetation ecosystem of the Qinghai–Tibet Plateau in China,considered to be the′′natural laboratory′′of climate change in the world,has undergone profound changes under the stress of global change.Herein,we a... The vegetation ecosystem of the Qinghai–Tibet Plateau in China,considered to be the′′natural laboratory′′of climate change in the world,has undergone profound changes under the stress of global change.Herein,we analyzed and discussed the spatial-temporal change patterns and the driving mechanisms of net primary productivity(NPP)in the Qinghai–Tibet Plateau from 2000 to 2015 based on the gravity center and correlation coefficient models.Subsequently,we quantitatively distinguished the relative effects of climate change(such as precipitation,temperature and evapotranspiration)and human activities(such as grazing and ecological construction)on the NPP changes using scenario analysis and Miami model based on the MOD17A3 and meteorological data.The average annual NPP in the Qinghai–Tibet Plateau showed a decreasing trend from the southeast to the northwest during 2000–2015.With respect to the inter-annual changes,the average annual NPP exhibited a fluctuating upward trend from 2000 to 2015,with a steep increase observed in 2005 and a high fluctuation observed from 2005 to 2015.In the Qinghai–Tibet Plateau,the regions with the increase in NPP(change rate higher than 10%)were mainly concentrated in the Three-River Source Region,the northern Hengduan Mountains,the middle and lower reaches of the Yarlung Zangbo River,and the eastern parts of the North Tibet Plateau,whereas the regions with the decrease in NPP(change rate lower than–10%)were mainly concentrated in the upper reaches of the Yarlung Zangbo River and the Ali Plateau.The gravity center of NPP in the Qinghai–Tibet Plateau has moved southwestward during 2000–2015,indicating that the increment and growth rate of NPP in the southwestern part is greater than those of NPP in the northeastern part.Further,a significant correlation was observed between NPP and climate factors in the Qinghai–Tibet Plateau.The regions exhibiting a significant correlation between NPP and precipitation were mainly located in the central and eastern Qinghai–Tibet Plateau,and the regions exhibiting a significant correlation between NPP and temperature were mainly located in the southern and eastern Qinghai–Tibet Plateau.Furthermore,the relative effects of climate change and human activities on the NPP changes in the Qinghai–Tibet Plateau exhibited significant spatial differences in three types of zones,i.e.,the climate change-dominant zone,the human activity-dominant zone,and the climate change and human activity interaction zone.These research results can provide theoretical and methodological supports to reveal the driving mechanisms of the regional ecosystems to the global change in the Qinghai–Tibet Plateau. 展开更多
关键词 NPP gravity center model driving mechanisms global change human activities Qinghai–Tibet Plateau
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Evolvement Characteristics of Population and Economic Gravity Centers in Tarim River Basin,Uygur Autonomous Region of Xinjiang,China 被引量:6
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作者 WANG Yang CHEN Yaning LI Zhi 《Chinese Geographical Science》 SCIE CSCD 2013年第6期765-772,共8页
Using the data at the county levcl and the regional gravity center model, we calculated six key socio-economic gravity centers, namely population, GDP, output values of primary, secondary and tertiary industries, and ... Using the data at the county levcl and the regional gravity center model, we calculated six key socio-economic gravity centers, namely population, GDP, output values of primary, secondary and tertiary industries, and arable land area in the Tarim River Basin for each year from 1980 to 2009. We inspected the spatial dynamics of these centers and found that the gravity centers of population and economy evolved simultaneously. The disproportional growth between the population and the economy is also analyzed. The results show that: 1) The gravity centers of the GDR the output values of the main three industries and arable land area show migration trending from southwest to northeast, while the population gravity center shows an excessive growth in the southwest during the same time period. The migration amplitude of the GDP and output values of primary industry, secondary industry, tertiary industry are measurably higher than that of the population. 2) The population gravity center has a negative correlation with the gravity centers of secondary and tertiary industries output values in both longitudinal and latitudinal directions, and a positive correlation with that of primary industry output value in the longitudinal direction. Based on the analysis of correlation coefficient and offset distance, the imbalance between the population and the economy has increased since the 1980s, with regional economic differences now exceeding the international cordon. 展开更多
关键词 regional gravity center model population gravity center economic gravity center Tarim River Basin
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Measuring Network Configuration of the Yangtze River Middle Reaches Urban Agglomeration:Based on Modified Radiation Model 被引量:3
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作者 ZHENG Wensheng KUANG Aiping +1 位作者 WANG Xiaofang CHEN Jing 《Chinese Geographical Science》 SCIE CSCD 2020年第4期677-694,共18页
The objective of this study is to develop a framework for re-examining and re-defining the classical concepts of spatial interaction and reorganization in the urban system.We introduce a modified radiation model for s... The objective of this study is to develop a framework for re-examining and re-defining the classical concepts of spatial interaction and reorganization in the urban system.We introduce a modified radiation model for spatial interactions,coupled with migration big data,transport accessibility algorithm,and city competitiveness assessment for efficient distribution of the inter-city flow through the network.The Yangtze River Middle Reaches(YRMR)urban agglomeration(UA)is chosen as the case study region to systematically identify and measure its spatial configuration and to gain insights for other UAs‘sustainable development in China.The results are also compared with those computed by the classical gravity model to systematically discuss the applicability of spatial interaction laws and models,and related practical policies for regional sustainable development are discussed based on the findings as well.The conclusions are highlighted below:1)Combining with the?city network paradigm‘and?central place theory‘can better express the spatial configurations of city systems in the context of?space of flows‘;2)The results validate the potentialities of a multi-analysis framework to assess the spatial configurations of city network based on the improved radiation model and network analysis tools;3)The applications of spatial interaction models should be considered according to the specific geographical entity and its spatial scale. 展开更多
关键词 spatial interaction city network radiation model gravity model urban agglomeration
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Spatial Interaction and Network Structure Evolvement of Cities in Terms of China's Rail Passenger Flows 被引量:12
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作者 DAI Teqi JIN Fengjun 《Chinese Geographical Science》 SCIE CSCD 2008年第3期206-213,共8页
Cities separated in space are connected together by spatial interaction (SI) between them. But the studies focusing on the SI are relatively few in China mainly because of the scarcity of data. This paper deals with t... Cities separated in space are connected together by spatial interaction (SI) between them. But the studies focusing on the SI are relatively few in China mainly because of the scarcity of data. This paper deals with the SI in terms of rail passenger flows, which is an important aspect of the network structure of urban agglomeration. By using a data set consisting of rail O-D (origin-destination) passenger flows among nearly 200 cities, intercity rail distance O-D matrixes, and some other indices, it is found that the attenuating tendency of rail passenger is obvious. And by the analysis on dominant flows and spatial structure of flows, we find that passenger flows have a trend of polarizing to hubs while the linkages between hubs upgrade. However, the gravity model reveals an overall picture of convergence process over time which is not in our expectation of integration process in the framework of globalization and economic integration. Some driven factors for the re-organization process of the structure of urban agglomeration, such as technique advance, globalization, etc. are discussed further based on the results we obtained. 展开更多
关键词 rail passenger flows urban agglomerations spatial interaction gravity model distance decay
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Parameter estimation of GTD model and RCS extrapolation based on a modified 3D-ESPRIT algorithm 被引量:2
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作者 ZHENG Shuyu ZHANG Xiaokuan +3 位作者 ZHAO Weichen ZHOU Jianxiong ZONG Binfeng XU Jiahua 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第6期1206-1215,共10页
The noise robustness and parameter estimation performance of the classical three-dimensional estimating signal parameter via rotational invariance techniques(3D-ESPRIT)algorithm are poor when the parameters of the geo... The noise robustness and parameter estimation performance of the classical three-dimensional estimating signal parameter via rotational invariance techniques(3D-ESPRIT)algorithm are poor when the parameters of the geometric theory of the diffraction(GTD)model are estimated at low signal-to-noise ratio(SNR).To solve this problem,a modified 3D-ESPRIT algorithm is proposed.The modified algorithm improves the parameter estimation accuracy by proposing a novel spatial smoothing technique.Firstly,we make cross-correlation of the auto-correlation matrices;then by averaging the cross-correlation matrices of the forward and backward spatial smoothing,we can obtain a novel equivalent spatial smoothing matrix.The formula of the modified algorithm is derived and the performance of this improved method is also analyzed.Then we compare root-meansquare-errors(RMSEs)of different parameters and the locating accuracy obtained by different algorithms.Furthermore,radar cross section(RCS)of radar targets is extrapolated.Simulation results verify the effectiveness and superiority of the modified 3DESPRIT algorithm. 展开更多
关键词 parameter estimation novel spatial smoothing scattering center geometric theory of diffraction(GTD)model radar cross section(RCS)extrapolation
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Effects of land use/cover change(LUCC) on the spatiotemporal variability of precipitation and temperature in the Songnen Plain,China 被引量:1
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作者 CHU Xiao-lei LU Zhong +1 位作者 WEI Dan LEI Guo-ping 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2022年第1期235-248,共14页
Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the con... Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature(P&T), is lacking. In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain(SNP) of Northeast China from 1980–2018. The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase(15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease(19 977.13 km;) due to the excessive agricultural utilization and development. Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980. The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land. These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland. In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP. 展开更多
关键词 land use/cover change(LUCC) PRECIPITATION TEMPERATURE Songnen Plain gravity center model satellite remote sensing
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Analysis of Land Use Change and Driving Factors in Mojiang County Based on PLUS Model
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作者 Chunfeng YANG Haiying PENG 《Asian Agricultural Research》 2023年第7期22-27,共6页
[Objectives]To explore the characteristics of land use change and its main influencing factors in Mojiang County from 2000 to 2020,and try to provide a scientific reference for alleviating the contradiction between ma... [Objectives]To explore the characteristics of land use change and its main influencing factors in Mojiang County from 2000 to 2020,and try to provide a scientific reference for alleviating the contradiction between man and land in Mojiang County and realizing the sustainable development of regional land resources.[Methods]Based on the land cover data and socio-economic data of Mojiang County from 2000 to 2020,the dynamic degree of land use,land use transfer matrix and center-of-gravity transfer model were calculated,and the temporal and spatial change characteristics and driving factors of various types of land use were calculated by PLUS model.[Results]From 2000 to 2020,the area and proportion of grassland,waters and construction land in Mojiang County showed an upward trend,while the area and proportion of cultivated land and forest land showed a downward trend.Among them,cultivated land was mainly converted into forest land and grassland,and some were converted into waters and construction land;forest land was mainly converted into cultivated land and grassland,and part of it was converted into waters and construction land.From 2000 to 2020,the center-of-gravity of cultivated land,forest land and construction land in Mojiang County moved to the southeast of the county,and the moving rates were 0.66,1.97 and 10.58 km/yr,respectively;the center-of-gravity of grassland and waters moved to the southwest of the county,and the moving rates were 1.30 and 20.20 km/yr,respectively.Distance from road,distance from government and distance from waters are the main driving forces affecting land use change in Mojiang County;the forecast shows that in 2040,the area of grassland and forest land in Mojiang County will continue to decrease,the area of cultivated land will turn to rise,and the area of waters and construction land will continue to rise.[Conclusions]Reasonable planning and optimizing the allocation of cultivated land and forest land structure and strict control of the expansion scale of construction land are necessary measures to ensure the coordinated development of regional land rational use and economic construction. 展开更多
关键词 Land use change Comparative analysis center of gravity PREDICTION PLUS model
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Exploring spatial-temporal change and gravity center movement of construction land in the Chang-Zhu-Tan urban agglomeration 被引量:10
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作者 LI Zhuo JIANG Weiguo +2 位作者 WANG Wenjie LEI Xuan DENG Yue 《Journal of Geographical Sciences》 SCIE CSCD 2019年第8期1363-1380,共18页
Urban agglomeration is caused by the continuous acceleration of the urbanization process in China. Studying the expansion of construction land can not only know the changes and development of urban agglomeration in ti... Urban agglomeration is caused by the continuous acceleration of the urbanization process in China. Studying the expansion of construction land can not only know the changes and development of urban agglomeration in time, but also obtain the great significance of the future management. In this study, taking Changsha-Zhuzhou-Xiangtan(Chang-Zhu-Tan) urban agglomeration in Hunan province as a study area, Landsat images from 1995 to 2014 and Autologistic-CLUE-S model simulation data were used. Moreover, several factors including gravity center, direction, distance and landscape index were considered in the analysis of the expansion. The results revealed that the construction area increased by 132.18%, from 372.28 km^2 in 1995 to 864.37 km^2 in 2014. And it might even reach 1327.23 km^2 in 2023. Before 2014, three cities had their own respective and discrete development directions. However, because of the integration policy implementation in 2008, the Chang-Zhu-Tan began to gather, the gravity center moved southward after 2014, and the distance between cities decreased, which was in line with the development plan of urban expansion. The research methods and results were relatively reliable, and these results could provide some reference for the future land use planning and spatial allocation in the urbanization process of Chang-Zhu-Tan urban agglomeration. 展开更多
关键词 construction LAND spatial change gravity center CHANG-ZHU-TAN urban AGGLOMERATION
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新疆耕地利用碳源/汇效应时空演变特征及其贡献因子
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作者 吕宁 国语 +5 位作者 彭琴 尹飞虎 张嘉淇 刘杏认 曾梅 许子函 《干旱区研究》 北大核心 2025年第1期179-190,共12页
为探明新疆耕地利用碳效应的长周期时空变化特征,准确评估其固碳增汇潜力,本文通过收集1991—2021年的新疆农业数据,采用碳吸收和排放系数法,测度分析新疆耕地利用过程碳排放量、碳吸收量、碳汇量的时序动态,并利用莫兰指数、标准差椭... 为探明新疆耕地利用碳效应的长周期时空变化特征,准确评估其固碳增汇潜力,本文通过收集1991—2021年的新疆农业数据,采用碳吸收和排放系数法,测度分析新疆耕地利用过程碳排放量、碳吸收量、碳汇量的时序动态,并利用莫兰指数、标准差椭圆和重心迁移分析耕地碳效应的空间分异、自相关性和演变特征,并揭示了其主要贡献因子。结果表明:(1)新疆耕地的碳吸收量远超碳排放量,总体表现为强的碳汇效应,且随时间推移碳汇能力呈增强态势,由1991年的830×10^(4)t增长至2021年的3429×10^(4)t。(2)强碳汇区域主要分布在耕地面积大且以种植玉米、小麦、棉花为主的生产区。(3)在县域尺度上耕地净碳汇具有显著的空间集聚特征,过去30 a耕地碳汇的重心总体上呈现由西南向东北迁移趋势,但仍集中于南疆的阿克苏地区。(4)施用化肥、机械作业、灌溉和农膜是主要的碳排放来源,其中,化肥和农膜投入对耕地碳排放贡献呈增加趋势。基于以上研究结果,提出可通过适度增加耕地面积、扩大南疆棉花和粮油作物种植布局、因地制宜推广麦后复播玉米、大豆、棉花提高复种指数、加大绿色农资物品投入等措施,在提高耕地产能保障粮食安全的同时,增强新疆耕地利用的碳汇效应。 展开更多
关键词 新疆耕地 碳源/汇效应 莫兰指数 标准差椭圆 重心迁移轨迹模型 时空演变特征
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多维邻近视角下长三角城市群知识溢出对新型工业化的影响研究
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作者 李子成 王珏 张烈嘉 《重庆文理学院学报(社会科学版)》 2025年第1期46-60,共15页
基于知识溢出推动新型工业化高质量发展的视野,利用2011—2021年长三角地区41个城市的面板数据,运用引力模型测度知识溢出,在多维邻近视角下构建空间计量模型,实证检验知识溢出对长三角城市群新型工业化发展的影响。研究结果表明:知识... 基于知识溢出推动新型工业化高质量发展的视野,利用2011—2021年长三角地区41个城市的面板数据,运用引力模型测度知识溢出,在多维邻近视角下构建空间计量模型,实证检验知识溢出对长三角城市群新型工业化发展的影响。研究结果表明:知识溢出效应主要集聚在省会城市,上海及江浙两地部分城市的知识溢出总量较高,而安徽各市的知识溢出总量均较低;长三角城市群新型工业化发展水平存在空间分异现象,上海和杭州等高等水平城市具备扩散效应,但这种效应逐渐降低,而虹吸效应不断增强;长三角城市群新型工业化发展水平在2011—2016年不断提高,在2016—2021年逐渐降低,且长三角各地区新型工业化差异在扩大,存在两极分化现象;在地理邻近、经济邻近、经济地理邻近下知识溢出对新型工业化发展具有显著的正向影响,存在明显的交流效应;知识溢出链锁效应明显,知识溢出促进产业结构高级化并结合数字经济推动新型工业高级化。 展开更多
关键词 知识溢出 新型工业化 引力模型 空间计量模型
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A gravity-spatial entropy model for the measurement of urban sprawl 被引量:2
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作者 LI Ji Hong QIU Rong Xu +1 位作者 XIONG Le XU Jia Dong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第1期207-213,共7页
Since the mid-twentieth century, most cities worldwide have undergone a rapid expansion in urban land use. Along with the expansion, several problems, such as excessive loss of prime agricultural land and increasing t... Since the mid-twentieth century, most cities worldwide have undergone a rapid expansion in urban land use. Along with the expansion, several problems, such as excessive loss of prime agricultural land and increasing traffic congestion have arisen. Thus, understanding and measurements of the expansion scale and its speed are crucial to planners and officials during urban planning and management processes. To measure such geographic phenomena, Shannon first devised entropy theory, and then Batty developed it into spatial entropy. The recently developed spatial entropy model, which was used to measure urban sprawl, introduced area to represent spatial asymmetry. However, most models did not consider spatial discretization, particularly the impact of distance. This study attempted to construct an integrated gravity-spatial entropy model to delineate distance and spatial diffusion impacts on population distribution. Then, we tested the model using Shanghai's temporal land use and community statistical data. Application results for the new gravity-spatial model show that it is a useful tool for identifying spatial and temporal variations of urban sprawl. 展开更多
关键词 ENTROPY spatial entropy gravity model Urban sprawl
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黄河下游豫鲁地区创新网络时空演化及环境效应研究
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作者 刘建华 赵鼎 +2 位作者 葛世帅 黄亮朝 崔源 《河南师范大学学报(自然科学版)》 CAS 北大核心 2025年第1期1-12,F0002,共13页
创新是城市与区域发展的核心动力,创新网络是提升区域创新能力的重要支撑.以黄河下游豫鲁地区为研究对象,采用修正后的引力模型来构建城市间的创新关联网络,运用社会网络分析法探究2014-2022年空间关联网络的演化与特征,并探析黄河下游... 创新是城市与区域发展的核心动力,创新网络是提升区域创新能力的重要支撑.以黄河下游豫鲁地区为研究对象,采用修正后的引力模型来构建城市间的创新关联网络,运用社会网络分析法探究2014-2022年空间关联网络的演化与特征,并探析黄河下游豫鲁地区创新网络对环境的影响.研究发现,整体来看,黄河下游豫鲁地区整体创新网络发展水平逐步提高,但空间分布不均的特征明显,创新网络整体发展水平仍处于起步阶段;分区域来看,河南省创新网络水平存在严重的两极分化现象,在空间上呈“米”字形分布.山东省整体创新网络水平高于河南省,创新资源分布较为均衡;研究期内,郑州、济南、青岛等城市是网络中的溢出主体,其中郑州、青岛是网络中的关键节点,影响整个网络稳定性.此外,研究区凝聚子群呈现出以郑州、济南、青岛为引领的“三核心”创新网络格局,但子群倾向于“抱团”,行政壁垒尚未消除;黄河下游豫鲁地区创新网络与环境污染呈倒“U”型关系,当创新网络水平跨过“拐点”时,才会对环境污染产生抑制作用,从而有效改善环境质量.在创新网络发展初期,开放程度、经济水平和人口规模扩大会加剧环境污染程度,而环境治理支出的增长和产业结构的优化能有效抑制环境污染. 展开更多
关键词 黄河下游 豫鲁地区 空间联系网络 引力模型 社会网络分析 环境污染
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中国数字贸易空间关联网络结构特征及其驱动因素
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作者 邵林 梁桂香 +1 位作者 杨玉波 徐诚诚 《华南理工大学学报(社会科学版)》 2025年第1期55-71,共17页
随着信息技术的迅猛发展和互联网的普及,数字贸易已成为中国经济增长的新引擎。采用熵值法评估2012—2021年我国31个省(自治区、直辖市)的数字贸易发展状况,进而通过修正的引力模型构建省域间数字贸易关联关系,并运用社会网络分析和QAP... 随着信息技术的迅猛发展和互联网的普及,数字贸易已成为中国经济增长的新引擎。采用熵值法评估2012—2021年我国31个省(自治区、直辖市)的数字贸易发展状况,进而通过修正的引力模型构建省域间数字贸易关联关系,并运用社会网络分析和QAP方法探讨我国省域数字贸易空间关联网络结构及其驱动因素。研究表明:我国各省(自治区、直辖市)在数字贸易发展方面存在不均衡现象,整体呈现“东部强、西部弱”的格局;数字贸易发展存在显著的空间关联网络结构特征,东部地区在数字贸易发展空间关联网络中占据中心地位,而西部地区相对边缘;东部地区多为净受益板块,西部地区多为净溢出板块,数字贸易次发达地区多为“经纪人”板块,其余地区为双溢出板块;互联网普及率、第三产业增加值占地区生产总值比重、城镇化水平越接近的地区,其数字贸易空间关联关系越紧密。研究为了解和推动我国数字贸易发展提供了一定的参考和启示。 展开更多
关键词 数字贸易 引力模型 空间关联 社会网络分析
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综合公园空间布局优化的模型构建及实证分析 被引量:1
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作者 刘志强 丁吉逸 +1 位作者 洪亘伟 余慧 《南方建筑》 CSCD 北大核心 2024年第1期88-95,共8页
综合公园作为重要且稀缺的城市公共资源,其合理布局对城市存量更新背景下优化公园体系、增进民生福祉具有重要意义。布局优化模型常用于解决公共服务设施布局问题,新重力P中值模型是一种综合多目标导向、设施供需匹配关系和复杂约束条... 综合公园作为重要且稀缺的城市公共资源,其合理布局对城市存量更新背景下优化公园体系、增进民生福祉具有重要意义。布局优化模型常用于解决公共服务设施布局问题,新重力P中值模型是一种综合多目标导向、设施供需匹配关系和复杂约束条件的布局优化方法。在辨析新重力P中值模型的基础上,综合考虑供给主体差异和模型求解难度,构建出面向城市综合公园布局优化的改进新重力P中值模型,主要修正内容如下:(1)通过细化供给主体,改良规模分配规则,改进新重力P中值模型未考虑现有公园和新建公园服务供给差异性的局限;(2)引入遗传算法寻优,解决非线性、多约束的复杂设施布局问题,实现模型求解以促进模型在公园实际规划中的推广应用。以苏州市中心城区为例,以多源数据为支撑,将研究尺度下沉至居住区尺度,实证结果表明模型优化后居民至邻近综合公园最大出行成本、平均出行成本和可达性基尼系数等指标均有改善,综合公园空间布局更为合理。研究结果可为综合公园布局规划提供有效决策工具,为公园绿地的精准化布局提供参考。 展开更多
关键词 综合公园 空间布局 新重力P中值模型 遗传算法 苏州
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我国青贮玉米生产的集聚演变及其作用机制——基于动态空间杜宾模型 被引量:1
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作者 颜姣姣 罗国庆 张翼 《饲料研究》 CAS 北大核心 2024年第1期175-180,共6页
为观测青贮玉米生产的动态变化,研究基于2001—2021年我国30个省面板数据,选用重心模型分析青贮玉米生产集聚区域变动。在此基础上,借助动态空间杜宾模型剖析要素投入、社会经济、政策支持对中国青贮玉米生产区域变动的影响。结果表明,... 为观测青贮玉米生产的动态变化,研究基于2001—2021年我国30个省面板数据,选用重心模型分析青贮玉米生产集聚区域变动。在此基础上,借助动态空间杜宾模型剖析要素投入、社会经济、政策支持对中国青贮玉米生产区域变动的影响。结果表明,我国青贮玉米存在空间聚集现象,即2001—2021年间我国青贮玉米生产量的莫兰指数总体上呈“先降再升再降再升”的发展态势。生产重心演变轨迹结果显示,我国青贮玉米生产区域重心呈现“先东北后西北、西南”的演变趋势。机制结果表明,粮食优势、财政扶持、务工收入增加是推进青贮玉米生产的主要驱动因素;生产基础设备、化肥施用、农业收益对本省份青贮玉米生产具有正向影响,但对相邻省份青贮玉米生产的影响不显著。 展开更多
关键词 青贮玉米 生产规模 重心演变轨迹 动态空间杜宾模型
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河南省耕地“非农化”时空演变特征分析 被引量:1
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作者 余庆年 王虎威 《国土资源科技管理》 2024年第2期50-61,共12页
深入理解和掌握耕地“非农化”的时空演变特征及其原因对保护耕地并确保粮食安全具有重要意义。本文针对中国产粮第二大省河南,以县域为单位,基于河南省1980—2020年土地利用长时序空间数据,采用重心转移模型和空间自相关分析等方法,定... 深入理解和掌握耕地“非农化”的时空演变特征及其原因对保护耕地并确保粮食安全具有重要意义。本文针对中国产粮第二大省河南,以县域为单位,基于河南省1980—2020年土地利用长时序空间数据,采用重心转移模型和空间自相关分析等方法,定量揭示全省158个县级评价单元1980—2020年来耕地“非农化”的空间分布特征、时空迁移路径和集聚特征,以期为河南省耕地资源的保护与可持续利用提供依据。结果表明:(1)河南省耕地资源东西分布差异大,集中连片耕地主要集中在东部,耕地总面积随时间推移呈波动减少。(2)耕地“非农化”等级时空差异较大,豫西地区耕地“非农化”较为缓和,中部和东部地区呈先快速上升后缓慢下降的态势。(3)河南省耕地“非农化”空间不均衡性增强,空间格局小幅波动,耕地“非农化”重心以先向东南和西南后向东北的路径迁移。(4)河南省耕地“非农化”空间分布格局在4个时期均呈现出集聚特性,空间集聚程度先增大后减小,高—高和低—低聚类主导格局变化。本研究揭示了1980—2020年河南省耕地“非农化”的时空演变格局,为政府管控耕地“非农化”现象、实现耕地资源的可持续发展提供参考和借鉴。 展开更多
关键词 耕地“非农化” 时空演变特征 重心模型 空间自相关
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