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Spatiotemporal characteristics and driving mechanisms of land use/land cover(LULC)changes in the Jinghe River Basin,China
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作者 WANG Yinping JIANG Rengui +4 位作者 YANG Mingxiang XIE Jiancang ZHAO Yong LI Fawen LU Xixi 《Journal of Arid Land》 SCIE CSCD 2024年第1期91-109,共19页
Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and... Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB. 展开更多
关键词 land use/land cover(LULC)changes driving mechanisms trajectory analysis geographical detector(Geodetector) Grain for Green Project Jinghe River Basin
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Land use change and its driving factors in the ecological function area:A case study in the Hedong Region of the Gansu Province,China
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作者 WEI Zhudeng DU Na YU Wenzheng 《Journal of Arid Land》 SCIE CSCD 2024年第1期71-90,共20页
Land use and cover change(LUCC)is important for the provision of ecosystem services.An increasing number of recent studies link LUCC processes to ecosystem services and human well-being at different scales recently.Ho... Land use and cover change(LUCC)is important for the provision of ecosystem services.An increasing number of recent studies link LUCC processes to ecosystem services and human well-being at different scales recently.However,the dynamic of land use and its drivers receive insufficient attention within ecological function areas,particularly in quantifying the dynamic roles of climate change and human activities on land use based on a long time series.This study utilizes geospatial analysis and geographical detectors to examine the temporal dynamics of land use patterns and their underlying drivers in the Hedong Region of the Gansu Province from 1990 to 2020.Results indicated that grassland,cropland,and forestland collectively accounted for approximately 99% of the total land area.Cropland initially increased and then decreased after 2000,while grassland decreased with fluctuations.In contrast,forestland and construction land were continuously expanded,with net growth areas of 6235.2 and 455.9 km^(2),respectively.From 1990 to 2020,cropland was converted to grassland,and both of them were converted to forestland as a whole.The expansion of construction land primarily originated from cropland.From 2000 to 2005,land use experienced intensified temporal dynamics and a shift of relatively active zones from the central to the southeastern region.Grain yield,economic factors,and precipitation were the major factors accounting for most land use changes.Climatic impacts on land use changes were stronger before 1995,succeeded by the impact of animal husbandry during 1995-2000,followed by the impacts of grain production and gross domestic product(GDP)after 2000.Moreover,agricultural and pastoral activities,coupled with climate change,exhibited stronger enhancement effects after 2000 through their interaction with population and economic factors.These patterns closely correlated with ecological restoration projects in China since 1999.This study implies the importance of synergy between human activity and climate change for optimizing land use via ecological patterns in the ecological function area. 展开更多
关键词 land use land type geographic detector driving mechanism Hedong Region
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Scale effect of coastal landscape pattern stability and driving forces:a case study of Guangdong Province,China
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作者 Kanglin Chen Yushi Li +1 位作者 Jianzhou Gong Gangte Lin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第9期122-135,共14页
The long-term dynamic evolution and underlying mechanisms of coastal landscape pattern stability,driven by strong anthropogenic interference and consequently climate change,are topics of major interest in national and... The long-term dynamic evolution and underlying mechanisms of coastal landscape pattern stability,driven by strong anthropogenic interference and consequently climate change,are topics of major interest in national and international scientific research.Guangdong Province,located in southeastern China,has been undergoing rapid urbanization over several decades.In this study,we quantitatively determined the scale threshold characteristics of coastal landscape pattern stability in Guangdong Province,from the dual perspective of spatial heterogeneity and spatial autocorrelation.An analysis of the spatiotemporal evolution of the coastal landscape was conducted after the optical scale was determined.Then,we applied the geodetector statistical method to quantitatively explore the mechanisms underlying coastal landscape pattern stability.Based on the inflection point of landscape metrics and the maximum value of the MoranⅠindex,the optimal scale for analyzing coastal landscape pattern stability in Guangdong Province was 240 m×240 m.Within the past several decades,coastal landscape pattern stability increased slightly and then decreased,with a turning point around 2005.The most significant variations in coastal landscape pattern stability were observed in the transition zone of rural-urban expansion.A q-statistics analysis showed that the explanatory power of paired factors was greater than that of a single driving factor;the paired factors with the greatest impact on coastal landscape pattern stability in Guangdong Province were the change in gross industrial output and change in average annual precipitation from 2010 to 2015,based on a q value of 0.604.These results will contribute to future efforts to achieve sustainable coastal development and provide a scientific basis and technical support for the rational planning and utilization of resources in large estuarine areas,including marine disaster prevention and seawall ecological restoration. 展开更多
关键词 coastal landscape pattern stability driving mechanism long-term dynamic evolution Guangdong Province optimal analysis scale
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Characteristics of Changes in Karst Rocky Desertification in Southtern and Western China and Driving Mechanisms 被引量:5
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作者 CHONG Guoshuang HAI Yue +2 位作者 ZHENG Hua XU Weihua OUYANG Zhiyun 《Chinese Geographical Science》 SCIE CSCD 2021年第6期1082-1096,共15页
The karst landform is a typical ecologically vulnerable region,and the problem of karst rocky desertification in southtern and western China has led to impoverishment and a degraded local ecological environment,which ... The karst landform is a typical ecologically vulnerable region,and the problem of karst rocky desertification in southtern and western China has led to impoverishment and a degraded local ecological environment,which severely limits local socioeconomic development.An effective and appropriate control of karst rocky desertification in southtern and western China requires knowledge about its characteristics of variation and driving mechanisms.In this study,we chose eight regions in the southtern and western China as research areas and analysed the characteristics of the changes in karst ecosystem patterns and rocky desertification from 2000 to 2015.Based on these characteristics,we present the mechanisms that drive karst rocky desertification in the southtern and western China by utilizing the redundancy analysis(RDA)ordination method.The results show that the total area of rocky desertification in southtern and western China had been continuously decreasing from 2000 to 2015,revealing a positive development trend in rocky desertification.Rocky desertification variations were mainly affected by human activities.The reduction in farmland area improved farmland management and increased regional gross industrial product,which together with continuously rising gross domestic product of the tertiary industry caused a positive rocky desertification development.However,the local karst tourism has a certain effect on inducing slight rocky desertification. 展开更多
关键词 southtern and western China KARST rocky desertification change characteristics driving mechanisms
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AN INSIGHT ON DRIVERS OF LAND USE CHANGE AT REGIONAL SCALE 被引量:2
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作者 SHAO Jing-an WEI Chao-fu XIE De-ti 《Chinese Geographical Science》 SCIE CSCD 2006年第2期176-182,共7页
The studies of driving forces of regional land use change (LUC) are to reveal the real motivation behind the LUC and its interacting mechanism, so as to simulate and predict the process of LUC. Presently, studies root... The studies of driving forces of regional land use change (LUC) are to reveal the real motivation behind the LUC and its interacting mechanism, so as to simulate and predict the process of LUC. Presently, studies rooting from different natural and socio-economic backgrounds and from different scales have deepened the people’s understanding and cognition to driving forces of regional LUC. Biophysical driving forces are relatively stable, and have the cumulating effects. Human driving forces are relatively active, and are main driving forces of short-term regional LUC. Existing regional LUC models can answer the three main problems: which contribution (why), which location (where) and what rate (when). But, regional land use system is defined as the self-organized system, usually affected by the cri- tical value area and sudden change, and controlled by different stages. To reduce the impact of critical threshold and break on land use system, the studies of LUC driving forces will aim at following priority areas: data linkage between remote sensing and no-remote sensing data; underlying driving force identification; driving factor quantification; driving factor scale dependence; and driving process integration simulation. 展开更多
关键词 land use change driving forces driving mechanism process simulation regional scale
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Spatial pattern and drivers of urbanization in China's mid-level developing urban agglomeration:A case study of Chang-Zhu-Tan 被引量:9
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作者 Yanhua He Yi Lin +2 位作者 Guohua Zhou Yixuan Zhu Kai Tang 《Regional Sustainability》 2021年第1期83-97,共15页
Urban agglomeration has become the main form of regional spatial organization in China.While most of the existing studies of urban agglomeration in China have focused on the eastern coastal areas,urban agglomeration w... Urban agglomeration has become the main form of regional spatial organization in China.While most of the existing studies of urban agglomeration in China have focused on the eastern coastal areas,urban agglomeration with mid-level development in the rest of the country has been overlooke1.To better understand the urbanization process of the mid-level developing urban agglomeration,this study investigated the clustering pattern and the drivers of both urban population and firm dynamics during 2005-2015 in the Changsha-Zhuzhou-Xiangtan(Chang-Zhu-Tan)urban agglomeration of China using the methods ofkernel density estimation and geographic detection.Our results show that centralization was obvious,although decentralization also occurred in Chang-Zhu-Tan,and that the spatial agglomeration was promoted by several factors,such as administrative resources,location advantage,labor cost,and consumption capacity.Some problems hindering the development of this region were also discovered:administrative resources played a critical role in urbanization because small towns and villages did not receive enough attention,and the effect of local policy was not as beneficial as expected.These findings partly explain the relatively slow development of mid-level developing urban agglomerations and have important implications for promoting healthier urbanization. 展开更多
关键词 URBANIZATION Spatial pattern Urban agglomeration Firm clustering Driving mechanism China
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Deformation mechanism of surrounding rocks and key control technology for a roadway driven along goaf in fully mechanized top-coal caving face 被引量:10
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作者 李学华 《Journal of Coal Science & Engineering(China)》 2003年第1期28-32,共5页
The variation of the stress in the bolted surrounding rocks structure of the roadway driven along goaf in a fully mechanized top coal caving face with moderate stable conditions are studied by using numerical calculat... The variation of the stress in the bolted surrounding rocks structure of the roadway driven along goaf in a fully mechanized top coal caving face with moderate stable conditions are studied by using numerical calculation. The essential deformation characteristics of the surrounding rocks in this kind of roadway are obtained and the key technology of bolting support used under these conditions is put forward. 展开更多
关键词 moderate stability gob side entry driving in a fully mechanized top coal caving face stress deformation bolting support
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Design Research on Drive System of Underwater Tapping Machine 被引量:1
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作者 喻开安 《China Ocean Engineering》 SCIE EI 2009年第1期175-184,共10页
The underwater tapping machine is composed of a center bit, a tapping cutter, a seal box, a main drive box, a boring bar assembly, a envelop, a gear case, a counter and so on. The drive system in underwater tapping ma... The underwater tapping machine is composed of a center bit, a tapping cutter, a seal box, a main drive box, a boring bar assembly, a envelop, a gear case, a counter and so on. The drive system in underwater tapping machine consists of a worm drive, a gear drive system and a screw drive. The worm drive is in the main drive box. The worm is connected with a hydraulic motor and driven by the hydraulic motor. The gear drive system is a combined gear train which is the combinations of the fixed axes and differential gear train in the gear case. On the one hand, by means of the fixed axes gear trains the turn and power of transmission shaft are transferred to the boring bar and the screw rod, causing differential turn between the boring bar and the screw rod. On the other hand, the turns of the boring bar and the screw rod are transferred to the differential gear train. The differential gear train is used to drive a special counter to count axial travel of the boring bar. The screw drive is composed of a feed screw and a nut on the boring bar. There is the differential turn between the boring bar and the feed screw. By means of the nut, the boring bar can feed automatically. With the movement of the sliding gear 7 in the gear case, the designed drive system can also be provided with the ability of fast forward and fast backward movement of the boring bar in its idle motion, resulting in the increase of the tapping efficiency. 展开更多
关键词 underwater tapping machine mechanical drive system axial travel counting device DESIGN
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Design, Manufacture and Measurements of Beta-Type Stirling Engine with Rhombic Drive Mechanism
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作者 Mohammed Yunus Mohammad S. Alsoufi Anil Kumar Rathod 《Modern Mechanical Engineering》 2016年第4期113-128,共17页
The purpose of carrying out present work is to design, build and test a rhombic drive Stirling engine with a β-type configuration consisting of two dynamic pistons (displacer and power) reciprocates in the in-line co... The purpose of carrying out present work is to design, build and test a rhombic drive Stirling engine with a β-type configuration consisting of two dynamic pistons (displacer and power) reciprocates in the in-line concentric cylinder arrangement. The displacement rod is assembled concentrically inside the power piston rod. The rhombic drive mechanism is proposed in such a way that, by using a pair of gear wheels the sliding motion of both piston rods is controlled and thus, an engine is balanced. The developed prototype has a swept volume of 75 cm<sup>3</sup> with the displacer piston and power piston cylinder hot ends heated by liquefied petroleum gas (LPG) burner and cooled water, respectively. It uses air as the working gas at atmospheric pressure for initial charging of the engine. Several designs were studied before settling on a β-type configuration. The LPG gas burner was considered as a potential heat source. The various elements of an engine (heater, cooler, re-generator, flywheel and piping systems) were designed, constructed and analyzed. The testing results revealed that the engine at initial atmospheric air filling started working in only about 120 seconds at an LPG heater temperature of 400℃ (824<sup>&deg;</sup>F) with 280 rpm. At a heater temperature of 550℃ (1022<sup>&deg;</sup>F), the engine speed was 630 rpm. At the engine speed of 245 rpm, the maximum torque was 0.215 Nm, while the maximum power was 8 Watts at 355 rpm. Engine speed increased with the increase of flame temperature. Several tests were performed on the engine to improve its running efficiency and critical problem areas were isolated and addressed. Moreover, results revealed that Stirling engines working with relatively low-temperature air are potentially attractive engines of the future, especially LPG powered low temperature differential Stirling engines. The Stirling engine was capable of generating between 50 to 100 Watts of electricity. 展开更多
关键词 Stirling Engine Engine Performance Rhombic Driving mechanisms β-Type
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Research on Influence Mechanism of Transmission Accuracy for Harmonic Drive Mechanism Considering Multi-factor Coupling
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作者 Peng ZHAO Shuang ZHANG Yang LIU 《Mechanical Engineering Science》 2021年第1期6-11,共6页
The influence mechanism of transmission accuracy for harmonic drive mechanism considering multi-factor coupling was studied. According to analysis of influence factors of transmission accuracy for harmonic drive mecha... The influence mechanism of transmission accuracy for harmonic drive mechanism considering multi-factor coupling was studied. According to analysis of influence factors of transmission accuracy for harmonic drive mechanism, it was obtained that the transmission errors of harmonic drive mechanism include processing errors and installation errors. The transmission error is produced by eccentric vector, it directly affects the rotation angle of output shaft and it makes harmonic drive mechanism produce backlash. Then analyze the movement error caused by the rigid wheel machining error, the flexible wheel machining error, the assembly error of the rigid wheel and the flexible wheel, the wave generator component, and the comprehensive expression method of motion error generated by each error source was obtained. The performance test device of space drive mechanism was used to test, and the law of the transmission accuracy of harmonic drive mechanism with temperature, speed and assembly clearance was obtained. The test results show that the transmission accuracy of harmonic drive mechanism decreases with increasing temperature, and the speed has little effect on the transmission accuracy of harmonic drive mechanism;the assembly quality has a significant impact on harmonic drive accuracy. 展开更多
关键词 harmonic drive mechanism transmission accuracy error source
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Quantitative distinction of the relative actions of climate change and human activities on vegetation evolution in the Yellow River Basin of China during 1981-2019 被引量:5
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作者 LIU Yifeng GUO Bing +3 位作者 LU Miao ZANG Wenqian YU Tao CHEN Donghua 《Journal of Arid Land》 SCIE CSCD 2023年第1期91-108,共18页
Under the combined influence of climate change and human activities,vegetation ecosystem has undergone profound changes.It can be seen that there are obvious differences in the evolution patterns and driving mechanism... Under the combined influence of climate change and human activities,vegetation ecosystem has undergone profound changes.It can be seen that there are obvious differences in the evolution patterns and driving mechanisms of vegetation ecosystem in different historical periods.Therefore,it is urgent to identify and reveal the dominant factors and their contribution rates in the vegetation change cycle.Based on the data of climate elements(sunshine hours,precipitation and temperature),human activities(population intensity and GDP intensity)and other natural factors(altitude,slope and aspect),this study explored the spatial and temporal evolution patterns of vegetation NDVI in the Yellow River Basin of China from 1989 to 2019 through a residual method,a trend analysis,and a gravity center model,and quantitatively distinguished the relative actions of climate change and human activities on vegetation evolution based on Geodetector model.The results showed that the spatial distribution of vegetation NDVI in the Yellow River Basin showed a decreasing trend from southeast to northwest.During 1981-2019,the temporal variation of vegetation NDVI showed an overall increasing trend.The gravity centers of average vegetation NDVI during the study period was distributed in Zhenyuan County,Gansu Province,and the center moved northeastwards from 1981 to 2019.During 1981-2000 and 2001-2019,the proportion of vegetation restoration areas promoted by the combined action of climate change and human activities was the largest.During the study period(1981-2019),the dominant factors influencing vegetation NDVI shifted from natural factors to human activities.These results could provide decision support for the protection and restoration of vegetation ecosystem in the Yellow River Basin. 展开更多
关键词 vegetation evolution driving mechanisms climate change human activities relative actions Geodetector Yellow River Basin
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A Comprehensive Evaluation Framework of Water-Energy-Food System Coupling Coordination in the Yellow River Basin,China 被引量:4
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作者 YIN Dengyu YU Haochen +3 位作者 LU Yanqi ZHANG Jian LI Gensheng LI Xiaoshun 《Chinese Geographical Science》 SCIE CSCD 2023年第2期333-350,共18页
For mankind’s survival and development,water,energy,and food(WEF)are essential material guarantees.In China,however,the spatial distribution of WEF is seriously unbalanced and mismatched.Here,a collaborative governan... For mankind’s survival and development,water,energy,and food(WEF)are essential material guarantees.In China,however,the spatial distribution of WEF is seriously unbalanced and mismatched.Here,a collaborative governance mechanism that aims at nexus security needs to be urgently established.In this paper,the Yellow River Basin in China with a representative WEF system,was selected as a case.Firstly,a comprehensive framework for WEF coupling coordination was constructed,and the relationship and mechanism between them were analyzed theoretically.Then,we investigated the spatiotemporal characteristics and driving mechanisms of the coupling coordination degree(CCD)with a composite evaluation method,coupling coordination degree model,spatial statistical analysis,and multiscale geographic weighted regression.Finally,policy implications were discussed to promote the coordinated development of the WEF system.The results showed that:1)WEF subsystems showed a significant imbalance of spatial pattern and diversity in temporal changes;2)the CCD for the WEF system varied little and remained at moderate coordination.Areas with moderate coordination have increased,while areas with superior coordination and mild disorder have decreased.In addition,the spatial clustering phenomenon of the CCD was significant and showed obvious characteristics of polarization;and 3)the action of each factor is self-differentiated and regionally variable.For different factors,GDP per capita was of particular importance,which contributed most to the regional development’s coupling coordination.For different regions,GDP per capita,average yearly precipitation,population density,and urbanization rate exhibited differences in geographical gradients in an east-west direction.The conclusion can provide references for regional resource allocation and sustainable development by enhancing WEF system utilization efficiency. 展开更多
关键词 water-energy-food(WEF) comprehensive framework coupling coordination relationship driving mechanism Yellow River Basin China
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Recent Advances in One‑Dimensional Micro/Nanomotors:Fabrication,Propulsion and Application 被引量:2
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作者 Yuhong Zheng He Zhao +2 位作者 Yuepeng Cai Beatriz Jurado‑Sanchez Renfeng Dong 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第2期114-142,共29页
Due to their tiny size,autonomous motion and functionalize modifications,micro/nanomotors have shown great potential for environmental remediation,biomedicine and micro/nano-engineering.One-dimensional(1D)micro/nanomo... Due to their tiny size,autonomous motion and functionalize modifications,micro/nanomotors have shown great potential for environmental remediation,biomedicine and micro/nano-engineering.One-dimensional(1D)micro/nanomotors combine the characteristics of anisotropy and large aspect ratio of 1D materials with the advantages of functionalization and autonomous motion of micro/nanomotors for revolutionary applications.In this review,we discuss current research progress on 1D micro/nanomotors,including the fabrication methods,driving mechanisms,and recent advances in environmental remediation and biomedical applications,as well as discuss current challenges and possible solutions.With continuous attention and innovation,the advancement of 1D micro/nanomotors will pave the way for the continued development of the micro/nanomotor field. 展开更多
关键词 1D micro/nanomotors Fabrication methods Driving mechanisms Applications
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Transformation and mechanisms of climate wet/dry change on the northern Tibetan Plateau under global warming:A perspective from paleoclimatology
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作者 Yu LI Zhansen ZHANG +5 位作者 Xueru ZHOU Minjun GAO Junjie DUAN Yaxin XUE Hao SHANG Shiyu LIU 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第6期1932-1951,共20页
The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,w... The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,westerly winds mainly control the climate.This article compares the wet/dry changes in the region during the mid-Holocene(MH)warm period,the medieval climate anomaly(MCA),the current warm period(CWP),and the future warm period from the perspective of paleoclimate.We found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon,and the region showed warm and humid climate characteristics.The MCA was mainly controlled by solar radiation,and there was a warm and dry phenomenon.The CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases,and the climate is becoming more arid.The wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the MCA.Continued warming will lead to the expansion of the westerly belt and a gradually humid climate.The future wet/dry changes will be more similar to the MH warm period. 展开更多
关键词 Northern Tibetan Plateau Wet/dry change Warm period similarity Driving mechanism Future assessment
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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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Spatial-Temporal Changes in Grain Production, Consumption and Driving Mechanism in China 被引量:10
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作者 XU Shi-wei WU Jian-zhai +3 位作者 SONG Wei LI Zhi-qiang LI Zhe-min KONG Fan-tao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第2期374-385,共12页
The spatial-temporal patterns of grain production and consumption have an important influence on the effective national grain supply on condition of tight balance in the total grain amount in China. In this paper, we ... The spatial-temporal patterns of grain production and consumption have an important influence on the effective national grain supply on condition of tight balance in the total grain amount in China. In this paper, we analyze the spatial-temporal pattems of grain production, consumption and the driving mechanism for their evolution processes in China. The results indicate that both gravity centers of grain production and consumption in China moved toward the northern and eastern regions, almost in the same direction. The coordination of grain production and consumption increased slightly from 1995 to 2007 but decreased from 2000 to 2007. There is a spatial difference between the major districts of output increase and the strong growth potential in grain consumption, which indicates an increasing difficulty in improving the regional coordination of grain production and consumption. The movement of the gravity center of grain production is significantly correlated with regional differences in grain production policy, different economic development models, and spatial disparity of land and water resource use. For grain consumption, the main driving factors include rapid urbanization, the upgrade of food consumption structure, and distribution of food industries. 展开更多
关键词 grain production grain consumption gravity center driving mechanism
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Optimal Design of a Main Driving Mechanism for Servo Punch Press Based on Performance Atlases 被引量:7
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作者 ZHOU Yanhua XIE Fugui LIU Xinjun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第5期909-917,共9页
The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and en... The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and energy saving.To effectively improve the performance and lower the cost,it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices.A new patented main driving mechanism and a new optimal design method are proposed.In the optimal design,the performance indices,i.e.,the local motion/force transmission indices ITI,OTI,good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are defined.The non-dimensional normalization method is used to get all feasible solutions in dimensional synthesis.Thereafter,the performance atlases,which can present all possible design solutions,are depicted.As a result,the feasible solution of the mechanism with good motion/force transmission performance is obtained.And the solution can be flexibly adjusted by designer according to the practical design requirements.The proposed mechanism is original,and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press. 展开更多
关键词 servo punch press main driving mechanism dimensional optimization transmission index performance atlas
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LAND USE/COVER CHANGE AND DRIVING FORCES IN SOUTHERN LIAONING PROVINCE SINCE 1950S 被引量:6
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作者 LILei ZHANGPing-yu HOUWei 《Chinese Geographical Science》 SCIE CSCD 2005年第2期131-136,共6页
Land use/cover change (LUCC) is a key aspect of global environment change, and in a sense indicates the influence of human activities on natural environment. Regional case study is the core of LUCC research. Taking th... Land use/cover change (LUCC) is a key aspect of global environment change, and in a sense indicates the influence of human activities on natural environment. Regional case study is the core of LUCC research. Taking the southern Liaoning Province, a coastal area facing the Bohai Sea and the Huanghai Sea, as an example, supported by ARCVIEW and ARC/INFO, this paper reconstructed LUCC patterns in three periods of 1954, 1976 and 2000, and analyzed their spatial-temporal changes from 1954 to 2000. On the base of these, it also studied the LUCC’s driving mechanism. The results show that the land transformation mainly occurs among cultivated land, forestland and urban and industrial land. Industrialization and urbanization in rural area are the major driving forces for cultivated land change, and the extension of the built-up area in cities is mainly the result of economic development and tertiary industry development, etc., which is at expense of cultivated land. 展开更多
关键词 land use/cover change (LUCC) spatial-temporal pattern driving mechanism southern Liaoning Province
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Driving Mechanism of Cultivated Land Transition in Yantai Proper,Shandong Province,China 被引量:5
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作者 QIN Weishan ZHANG Yifeng LI Guangdong 《Chinese Geographical Science》 SCIE CSCD 2015年第3期337-349,共13页
Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the q... Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the quantitative perspective. Based on the vector data of land use in 1990, 2000 and 2009 of Yantai Proper, Shandong Province China, 11 explanatory variables were chosen from two aspects: the elevation, slope, cost distance to major water area and cost distance to minor water area, which presented physical factors; cost distance to district center, cost distance to town center, cost distance to city expansion center, cost distance to major roads, cost distance to city roads, cost distance to county roads and cost distance to rural roads, which presented the socio-economic factors. Combined with spatial analysis tools and Logistic regression analysis model, we construct Logistic regression analyses with four objectives that were urban construction land, rural residential land, orchard and other lands. The results show that, cost distance to district center, cost distance to town center, cost distance to city expansion center and cost distance to city roads are the significant explanatory variables for the transition of cultivated land into urban construction land. The main explained factors on the transition of cultivated land into rural residential land are slope, cost distance to town center, cost distance to county roads and cost distance to rural roads. Slope, cost distance to minor water area, cost distance to town center, cost distance to county roads and cost distance to rural roads are the significant explanatory variables for the transition of cultivated land into orchard land. Elevation, slope, cost distance to major water area and cost distance to minor water area are the main explanatory variables on the transition of cultivated land into other land uses. 展开更多
关键词 cultivated land use transition driving mechanism Yantai Proper China
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Spatio-temporal Differentiation of Residential Land for Coastal Town: A Case Study of Dalian Jinshitan 被引量:3
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作者 YANG Jun SUN Jing +2 位作者 ZHAO Hongdan XI Jianchao LI Xueming 《Chinese Geographical Science》 SCIE CSCD 2016年第4期566-576,共11页
Based on SPOT5 satellite remote sensing images and land use data in five time phases covering the period 1988–2012, the distribution characteristics, spatial differentiation processes, and driving mechanisms affectin... Based on SPOT5 satellite remote sensing images and land use data in five time phases covering the period 1988–2012, the distribution characteristics, spatial differentiation processes, and driving mechanisms affecting the residential land of the Jinshitan Tourist Resort were studied. The work included a combination of GIS technology, adoption of the differentiation index D, and the multi-group differentiation-measure model D(m). The results provided a basis for the following conclusions: 1) From 1988 to 2012, the degree of differentiation of the rural residential land first decreased, and then increased. The general residential, commercial residential and garden-house land-types all showed declining trends, of which the garden-house type presented the most intense volatility. 2) The overall background of the traditional residential land type was gradually replaced by a new residential land type, and the total area of residential land increased year by year, significantly improving the overall residential conditions. The areas of the new residential land type showed growth, and were increasingly widely distributed in the coastal tourist resorts, transportation corridors, and scenic areas. 3) Government policy, social differentiation, market mechanisms, and individual choices(along with other factors) were mutually promoted, although still restrained. However, all of these factors interacted to constrain the developmental direction and the processes affecting tourism real estate in the Dalian Jinshitan Tourist Resort. 展开更多
关键词 residential space differentiation differentiation degree residential conditions driving mechanism Dalian Jinshitan
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