检索结果-南通市图书馆

Recent progress in polymerization-induced self-assembly:From the perspective of driving forces

在线全文

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2024年第1期5卷 47-66页

作者： Zizhuo Zhao Shujing Lei Min Zeng Meng Huo Department of Chemistry Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhouP.R.China Department of Chemistry University of WarwickCoventryUK

Polymerization-induced self-assembly(PISA)enables the simultaneous growth and self-assembly of block copolymers in one pot and therefore has developed into a high-efficiency platform for the preparation of polymer assemblies with high concentration and excellent *** the past decade,the driving force of PISA has extended from hydrophobic interactions to other supramolecular interactions,which has greatly innovated the design of PISA,enlarged the monomer/solvent toolkit,and endowed the polymer assemblies with intrinsic dynamicity and *** unravel the important role of driving forces in the formation of polymeric assemblies,this review summarized the recent development of PISA from the perspective of driving *** by this goal,here we give a brief overview of the basic principles of PISA and systematically discuss the various driving forces in the PISA system,including hydrophobic interactions,hydrogen bonding,electrostatic interactions,andπ-π***,PISA systems that are driven and regulated by crystallization or liquid crystalline ordering were also highlighted.

关键词： driving forces electrostatic interactions hydrogen bonding hydrophobic interactions polymerizationinduced self-assembly

driving forces behind the construction of an eco- compensation mechanism for wetlands in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2016年第3期10卷 487-497页

作者： Changhai WANG Rural Development Institute Chinese Academy of Social Sciences Beijing 100732 China Collaborative Innovation Center for Rural Reform and Development Beijing 100732 China

This research revealed important driving forces behind the construction of an eco-compensation mechan- ism for wetlands （DFEMW） in China. Using China＇s provincial panel data from 1978 to 2008, a fixed-effects model was used to analyze the impacts of agricultural production systems on wetlands. We identified three DFEMW as follows： the change of wetland resources and protection measures in China; declaration and implementation of the provincial Wetland Protection Ordinance; and wetland degradation by agricultural production systems, which necessitated the establishment of a wetland eco-compensation mechanism. In addition to the DFEMW, a significant positive correlation between wetland area and both rural population and gross agricultural production was identified, in addition to a negative correlation with chemical fertilizer usage, reser- voir storage capacity, and irrigation area, The underlying reasons for the serious degradation and inadequate protection of wetlands were market failure and government failure; these were the driving forces behind the need to establish a wetland eco-compensation mechanism. From a governmental perspective, it has been difficult to rectify market failures in resource distribution and thus to prevent wetland degradation. Factors include conflicts of interest, lack of investment, effective special laws, a simple means to protect wetlands, and a multidisciplinary management system. Therefore, the key factor is the coordination of interest relationships between those who utilize wetlands and those who seek to minimize wetland degradation and effectively protect wetlands.

关键词： China driving forces eeo-eompensation,socio-econorrflc factors wetlands

DYNAMICS OF SANDY DESERTIFICATION AND ITS driving forces IN WESTERN JILIN PROVINCE

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2004年第1期14卷 57-62页

作者： LIFang LIUZhi-ming XortheastInstituteofGeographyandAgriculturalEcology ChineseAcademyofSciences130012P.R.China InstituteofAgriculturalDirisionsofJilinProvince Changchun130012P.R.China

By establishing the interpreting elements, and applying supervised classification, the sandy desertific- ation was interpreted and the desertified land areas of the counties in the western Jilin Province in 1986 and in 2000 were obtained. Taking Tongyu and Qian’an as examples, the natural driving forces and man-made driving forces were analyzed. The paper comes the conclusions that the material sources and the warming and dry climate are the internal causes of potential land desertification; the irrational human activities, such as destroying forest and reclaiming the grassland, are the external causes of potential land desertification; while more rational human activities, such as planting trees and restoring grassland can reverse the land desertification. Furthermore, the countermeasures and suggestions for the development of agriculture and animal husbandry in the western Jilin Province are put forward.

关键词： sandy desertification remote sensing dynamics driving forces western Jilin Province

China's Urbanization in 1949–2015: Processes and driving forces

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2017年第6期27卷 847-859页

作者： GU Chaolin HU Lingqian Ian G.COOK School of Architecture Tsinghua University School of Architecture and Urban Planning University of Wisconsin-Milwaukee School of Humanities and Social Science Liverpool John Moores University

The pace and scale of China＇s contemporary urbanization are stunning. This paper reviews process and the underlying driving forces of China＇s urbanization between 1949-2015. Contemporary China＇s urbanization has experienced four stages, and each has had different driving forces： 1） economic re-construction and industrialization-led urbanization 0949-1977）; 2） economic reform and mar- ket-led urbanization （1978-1995）; 3） economic globalization and the global-local urbanization （1996-2010）; and 4） the land-economy- led urbanization （2010-）. These urbanization processes and driving forces will undoubtedly provide scientific reference and have sig- nificant implications for developing countries, especially African countries, to formulate their urbanization public policies.

关键词： urbanization Contemporary China urbanization level urbanization process driving forces public policies

ANALYSIS OF driving forces ON THE CHANGE OF HISTORICAL FARMLAND USE IN SHANDONG PROVINCE DURING THE QING DYNASTY (1644-1911)

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2003年第3期13卷 207-215页

作者： ZHANG Xue-in, GE Quan-heng, ZHENG Jing-un(Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, P. R. China) Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing P. R. China

How land-cover has been changed by human use over the last 300 years is oneof the five overarching questions guiding the Land-use/Cover Change (LUCC) Science/Research *** has variety of historical documents providing unique data superiority. So the characteristicsof farmland area in Shandong Province during the Qing Dynasty (1644-1911) are summarized firstly: 1)the rising trend of farmland area was striking; 2) farmland area had remarkable fluctuation; 3)farmland area per capita decreased dramatically; 4) wasteland reclamation index increased ***, the driving forces of farmland area change are analyzed. It is concluded that natural andhuman factors are jointly influential. Among the driving forces, human dimensions are the mainfactors of farmland area change, which direct the general tendency of the changes mentioned *** the natural factors influence the stability of farmland area as well. Variation of the naturalfactors would act as the major contributory factor to farmland area change during years or periodsof abrupt climatic changes, or during the intensive occurring periods of natural hazards. Besides,the passive aspects of human factors, such as war chaos also influenced the fluctuation of thefarmland area. This research indicates that it is feasible to study the land-use/cover change byChinese historical literatures, which has huge potential to provide a comprehensive picture of thegrowing dominance of human land-use and land-cover patterns that can be used in many global changeresearch projects.

关键词： farmland driving forces shandong province qing dynasty

The spatiotemporal changes of marshland and the driving forces in the Sanjiang Plain, Northeast China from 1980 to 2016

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2020年第1期9卷 263-275页

作者： Zhen Li Miao Liu Yuanman Hu Zhenshan Xue Jinling Sui CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China Research Center of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

Background:Wetland loss is a global concern due to its enormous ecosystem ***,a typical natural wetland,which is concentrated in the Sanjiang Plain,has undergone dramatic loss in the last several *** spatiotemporal changes in marshland were studied based on Landsat images of the Sanjiang Plain from 1980 to 2016 with the land use maps in 1980,1995,2000,2005,2010,and 2016 using land use dynamic degree and landscape *** driving forces of marshland loss,including biophysical factors,socio-economic factors,and land management,were analyzed with boosted regression trees(BRTs)***:The area of marshland loss was 7372 km^(2),which accounted for 65.7%of the area of marshland in 1980;however,the paddy field area was expanded by 22,313 km^(2).The lost marshland was mainly converted to dry farmland(47.5%)and paddy field(47.2%)during *** the landscape pattern of the study area and marshland became increasingly *** relatively important factors responsible for marshland loss were biophysical factors,socio-economic factors,and land management,which accounted for 65.2%,25.5%,and 8.4%,*** most important driving forces with high“relative influence”were“distance to river,”which accounted for 20.6%of the total variance ***“relative influence”of potential crop yield and ditch density reached 20.2%and 8.4%,***:Significant land use changes have occurred in the Sanjiang Plain over the past 37 years,with characteristics of rapid paddy field expansion and drastic marshland ***,marshland fragmentation continued to *** was the main reason for the large-scale marshland *** factors influenced the decisions regarding the locations of marshland ***,climate factors(i.e.,average annual precipitation and average annual temperature)also played an important role in marshland *** results can provide helpful knowledge for understanding the patt

关键词： Land use change Marshland loss driving forces The Sanjiang Plain

Geographic concentration and driving forces of agricultural land use in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2012年第1期6卷 48-56页

作者： Yuluan ZHAO Xiubin LI Liangjie XIN Haiguang HAO Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Chinese Academy for Environmental Planning Beijing 100012China

Since the 1990s, China has entered the middle phase of urbanization which leads to the existence of significant geographic concentration of agricultural land use. The average value of regional concentration degree of ten representative crops in China was 59.03%, showing a high degree of geographic concentration in farming. Some typical agriculture provinces in farming have arisen. The degree of geographic concentration in farming has been enhanced, with the average degree of regional concentra- tion often crops increasing considerably by 3.83% in 2009 compared to that in 1990 （55.20%）. The spatial growing center of farming was found to move westward and northward during 1990-2009. Meanwhile food production concentrated in the Northeast China and main producing area, and cash crops production concentrated in Northwest China. Off-farm employment of rural labor force, commercialization of agricultural product and regional comparative advantage are the main driving forces of geographic concentration of agricultural land use. Govern- mental policies with regional differences should be considered to promote further development of agriculture.

关键词： agricultural land use geographic concentra-tion driving forces China

Urban expansion patterns and their driving forces based on the center of gravity-GTWR model:A case study of the Beijing-Tianjin-Hebei urban agglomeration

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2020年第2期30卷 297-318页

作者： WANG Haijun ZHANG Bin LIU Yaolin LIU Yanfang XU Shan ZHAO Yuntai CHEN Yuchen HONG Song School of Resources and Environmental Science Wuhan UniversityWuhan 430079China Key Laboratories of Geographic Information Systems Ministry of EducationWuhan UniversityWuhan 430079China Collaborative Innovation Center for Geospatial Information Science Wuhan UniversityWuhan 430079China Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China China Land Survey and Planning Institute Beijing 100035China

Research into urban expansion patterns and their driving forces is of great significance for urban agglomeration development planning and *** this paper,we reveal the multi-dimensional characteristics of urban expansion patterns,based on the intensity index of the urban expansion,the differentiation index of the urban expansion,the fractal dimension index,the land urbanization rate,and the center of gravity model,by taking the Beijing-Tianjin-Hebei(Jing-Jin-Ji)urban agglomeration as an *** then build the center of gravity-geographically and temporally weighted regression(GTWR)model by coupling the center of gravity model with the GTWR *** the analysis of the temporal and spatial patterns and by using the center of gravity-GTWR model,we analyze the driving forces of the urban land expansion and summarize the dominant development modes and core driving forces of the Jing-Jin-Ji urban *** results show that:1)Between 1990 and 2015,the expansion intensity of the Jing-Jin-Ji urban agglomeration showed a down-up-down trend,and the peak period was in *** 2005,high-speed development took place in Beijing,Tianjin,Baoding,and Langfang;after 2005,rapid development was seen in Xingtai and Handan.2)Although the barycenter of cities in the Jing-Jin-Ji urban agglomeration has shown a divergent trend,the local interaction between cities has been enhanced,and the driving forces of urban land expansion have shown a characteristic of spatial spillover.3)The spatial development mode of the Jing-Jin-Ji urban agglomeration has changed from a dual-core development mode to a multi-core development mode,which is made up of three functional cores:the transportation core in the northern part,the economic development core in the central part,and the investment core in the southern *** synergistic development between each functional core has led to the multi-core development mode.4)The center of gravity-GTWR model combines the analy

关键词： urban land expansion driving forces center of gravity geographically and temporally weighted regression Jing-Jin-Ji

Spatio-temporal Pattern and driving forces of Comprehensive Agricultural Productivity in Jilin Province,China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2020年第3期30卷 493-504页

作者： LIU Yunda TONG Lianjun Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China University of Chi-nese Academy of Sciences Beijing 100049China

Improving comprehensive agricultural productivity is an important measure to realize agricultural *** on the data from Jilin Statistical Yearbook,this study analyzed the spatial and temporal characteristics of comprehensive agricultural productivity discrepancy in the main agricultural production areas of Jilin Province,*** comprehensive agricultural productivity of 25 county-level administrative units were evaluated by a comprehensive index system based on five aspects which included 20 indicators from 2004 to *** pattern of the discrepancy was analyzed by the spatial differentiation indices and spatial convergence *** results were as follows:1) the overall comprehensive agricultural productivity was in a ’W-type’ rising trend;2) the discrepancy was in’inverted W-type’ trend;3) the spatial distribution characteristics were mainly discrete plaque and ’inverted V-type’;4) the formation of differences was forced by a combination of internal and external driving *** study demonstrates the effectiveness of rising agricultural productivity and the level of economic and social developments in different counties in Jilin Province.

关键词： spatio-temporal pattern comprehensive agricultural productivity spatial convergence/divergence driving forces Jilin Province,China