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1.
Based on the fractal theory, the spatial structure of China's vegetation has been analyzed quantitatively in this paper. Some conclusions are drawn as the following. 1) The relationships between size and frequency of patch area and patch shape index exist objectively for China's vegetation. 2) The relationships between perimeter and area exist objectively for China's vegetation. 3) The fractal dimension of evergreen needleleaf forests on mountains in subtropical and tropical zones is the largest, while the smallest for deciduous broadleafand evergreen needleleaf mixed forests in temperate zone, reflecting the most complex spatial structure for evergreen needleleaf forests on mountains in subtropical and tropical zones and the simplest for deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone. 4) The fractal dimensions of China's vegetation types tend to decrease from thc subtropics to both sides. 5) The stability of spatial structure of deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone is the largest, while the smallest for double-cropping rice, or double-cropping rice and temperate-like grain, and tropical evergreen economic tree plantations and orchards, reflecting the steadiest for deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone and the most unstable for double-cropping rice, or double-cropping rice and temperate-like grain, and tropical evergreen economic tree plantations and orchards in spatial structure. 6) The stability of spatial structure of China's vegetation tends to decrease from the temperate zone to both sides, it is significantly pertinent to understand the formation, evolution, dynamics and complexity rule of ecosystem of vegetation.  相似文献   

2.
Chinaˊs urban reforms have brought social progress and development,but a comprehensive national system of social welfare(for example,unemployment insurance,pensions,medical care and public housing)for new migrants from rural areas is lacking.One of the most remarkable changes in Chinese cities in the last decade was a change in so-cial“equality“,with the rise of new poverty both in individual communities and some social groups in urban society.Howev-er,there is little social assistance and public infrastructure for the migrants.Governments or communities or individual should pay attention to the control of new urban poverty and new slums.This paper consider that it is necessary to launch a successful policy,which include mainly:1)accommodating urban growth through low-cost investment projects;2)ur-ban economy depends heavily on successful macroeconomic policy;3)to broaden the three channels linking adjustment to the incidence of urban poverty;4)to restructure urban economic based on the high or new technology;5)to coordi-nate relationship between urban economic growth and environment management for sustainable development of Beijingˊs metropolitan fringe.  相似文献   

3.
This paper meant to analyze the spatial evolution of a large country in its process of integration with the world economy in general, and, to look into the possible effect of China‘s accession into WTO on the future development of its spatial economy in particular. Through an approach of increasing returns, external economy, product differentiation and path-dependence, with foreign trade costs incurred by different regions within the large country discriminated, a model of investment and employment flow is developed as a simulation of a large country‘s process of integration with the world economy. The modeling indicates that in the process of integration, as there exist differences in foreign trade costs among different regions within the large country, either the spatial economy of the country deviates from its symmetric structure in autarky and falls into a core-periphery relationship, or the effect of industrial agglomeration is reinforced, amplified and locked in, if the agglomeration had been started. The economic gap on either the aggregate or structural basis between different regions within the large country will increase rapidly as the integration proceeds.  相似文献   

4.
1 Introduction Northeast China consists of the three provinces of Heilongjiang, Jilin and Liaoning. Since the founding of the People's Republic of China in 1949, this region has supported the whole country with huge quantity of grain, raw materials, primary products, and heavy industrial products at the cost of environment and resources, and thereafter became an old industrial base as well as an important marketable grain base in the whole country (Zhang et al., 2004). However, since the 19…  相似文献   

5.
Human beings have had a tremendous impact on natural ecosystems and are now the principal power to change the biosphere.It is logical that we should pay close attention to the interaction between human systems and environ-mental systems.Taking Minqin bsin ,Gansu Province,as a case,this paper focuses on the evolution of regional physic-cal environments and the cultural systems by which people maintain their relationships with those environments.This pa-per presents the conceptural framework for the man-land system.Expecting to accelerate the regional sustainable develop-ment,it also analyses the evolutionary mechanism of regional man-land system.On the basis of reviewing and analyzing the evolution of man-land system in Minqin basin,the paper also brings forward an adujusting mode for the studied area, which consists of three aspects:to build up a concept that economic growth must harmonize with environmental qualityˊs and land productivityˊs improvement;to make a whole planning and management in the drainage area;and to push for-ward the technique of water-saving irrigation and establish water-saving agricultural system. Itˊs meaningful for resource exploitation and sustainable development of Chinese northwestern arid area,which is represented by Minqin basin,by under-standing what great changes the basin has experienced is experiencing at the global background,and studying its time standing what great changes the basin has experienced and is experiencing at the global background,and studying its time order and territorial structure ,the systemˊs character and law of evolution,trend and the regulating ways to improve man-land relationship.  相似文献   

6.
1 INTRODUCTIONOne of the 7 key plans of IGBP (International Geo-Biosphere Project) is the PAGES (Past Global Changes), of which the relation of mutual influence of mankind and natural environmental changes during historic period has attracted great attentions over the world (CHEN,1992; Committee of National Natural Science Foundation of China, 1995). Due to the atrocious natural conditions, study of this issues are much more backward in southern Xinjiang. So to investigate and…  相似文献   

7.
The economic system of mining city is of typical vulnerability characteristics that can be manifested by its high economic sensitivity and lack of response capacity to the gradual depletion of regional mineral resources. Taking Fuxin City of Liaoning Province as a case, this paper established an economic vulnerability assessment method integrating BP neural network with vulnerability index, then carried out an economic vulnerability assessment of Fuxin during 1989–2006. The results indicate that: 1) Affected by the gradual depletion of regional mineral resources, the economic development of Fuxin had kept high economic sensitivity from 1995 to 2001, and the response capacity to cope with and adapt to the impacts of the perturbation of mineral resources was weak and relatively lag. The evolution of economic vulnerability can be divided into three stages: in 1989–1994, the economic vulnerability of Fuxin City decreased slowly; in 1995–2001, the beginning stage of economic transformation, the economic vulnerability of Fuxin City went up rapidly; in 2002–2006, the economic vulnerability of Fuxin City descended and showed a trend to be stable. 2) The influence of economic sensitivity on Fuxin’s economic vulnerability is more evident than that of response capacity. 3) The decreasing supply of mineral resources and the simple industrial structure are main factors leading to the economic sensitivity of Fuxin. 4) The improvement of economic response capacity of Fuxin has typical characteristics of input-driven growth, and external assistance is of great importance to the rapid improvement of economic response capacity of Fuxin. And 5) the change from the simple industrial structure to diversified one of Fuxin is still unaccomplished, and the contribution of non-coal-based industry to local economic development is relatively limited. Foundation item: Under the auspices of Key Program of National Natural Science Foundation of China (No. 40635030), Knowledge Innovation Programs of the Chinese Academy of Sciences (No. KZCX2-YW-342, No. KZCX2-YW-321)  相似文献   

8.
1 Introduction The industrial location is always the focus in academic circles and any analysis on industrial location can not avoid the agglomeration mechanism formed as the result of the industrial location. The study on the industrial location has become the focus for the massive theoretical location problems about agglomeration since the 1970s, which has a great influence on the formation of the in- dustrial location. In order to make more study of its in- fluence, it is necessary to resea…  相似文献   

9.
Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the western Jilin Province in 1980-2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da'an during 1995-2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography, predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da'an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da'an fluctuated greatly. The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development.  相似文献   

10.
Based on dynamic theory of system, agriculture is a complex system composed by element, structure, function and development. Firstly, this paper analyzes their connotation and relationship, which could be simply described that in virtue of element integrating and structure optimizing, agricultural system may achieve multifunctionality to meet increasingly diverse demands. As a case study of Suzhou, it concludes that Suzhou has a LP-dependence on agricultural element, and the growth extent of agricultural productivity correlates to the ratio of agricultural labor reducing rate to farmland reducing rate. Agricultural structure of Suzhou changed with time, and in the early 1980s and 2000s it was most notable. Correspondingly, agricultural function has experienced a succession process: ‘production’, ‘production-living’, and ‘production-living-ecology’. At last, based on questionnaires and interviews, some new characteristics and problems of agricultural development in coastal developed region of China have been put forward. Meanwhile, some typical patterns of modern agriculture in Suzhou which adapt to system evolving are also brought up such as export-oriented agriculture, enterprises-leading agriculture, agricultural science and technology parks, characteristic and stereoscopic agriculture, tourism and sightseeing agriculture. Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40635029, No. 40771014)  相似文献   

11.
RIVERINE INORGANIC CARBON DYNAMICS: OVERVIEW AND PERSPECTIVE   总被引:1,自引:1,他引:0  
1INTRODUCTION River systems are the major linkage between the land and the ocean, not only transporting carbon from terres- trial environment to the ocean, but also exchanging CO2 with the atmosphere, actively involved in the global car- bon biogeochemical cycle (RICHEY et al., 2002; COLE and CARACO, 2001). The inorganic carbon, mainly o- riginating from soil CO2, carbonate minerals and atmo- sphericCO2,constitutedthegreatpart(about 60%) ofthe riverine carbon exported to the ocean…  相似文献   

12.
1INTRODUCTIONAfter2decades'opendoorpractice,Chinahasnotonlybeenabigplayerasanimportanthostnationtoforeigndirectinvestment(FDI),butalsothelargestFDIhomenationamongthedevelopingcountries(SUN,1998;ZHANG,1995;WorldInvestmentReport,1998).Infact,sincethelate1980s,theChinesegovernmenthasnotsimplyputitseffortintoexportingmade-in-China"productstoearnforeigncurrencyorintoencouragingforeigninwardcapital.Ithasactivelyencourageditsmanufacturerstoinvestoverseas,andhasdeliberatelyandstrategical…  相似文献   

13.
This paper presents a development of the extended Cellular Automata (CA), based on relational databases(RDB), to model dynamic interactions among spatial objects. The integration of Geographical Information System (GIS)and CA has the great advantage of simulating geographical processes. But standard CA has some restrictions in cellularshape and neighbourheod and neighbour rules, which restrict the CA‘s ability to simulate complex, real world environ-ments. This paper discusses a cell‘‘s spatial relation based on the spatial object‘s geometrical and non-geometrical characteris-tics, and extends the cell‘‘ s neighbour definition, and considers that the cell‘ s neighbour lies in the forms of not only spa-tial adjacency but also attribute correlation. This paper then puts forward that spatial relations between two different ceilscan be divided into three types, including spatial adjacency, neighbourheod and complicated separation. Based on tradition-al ideas, it is impossible to settle CA‘‘s restrictions completely. RDB-based CA is an academic experiment, in whichsome fields are designed to describe the essential information needed to define and select a cell‘‘s neighbour. The cultureinnovation diffusion system has multiple forms of space diffusion and inherited characteristics that the RDB-based CA iscapable of simulating more effectively. Finally this paper details a successful case study on the diffusion of fashion weartrends. Compared to the original CA, the RDB-based CA is a more natural and efficient representation of human knowl-edge over space, and is an effective tool in simulating complex systems that have multiple forms of spatial diffusion.  相似文献   

14.
1 Introduction China’s success in reform and opening up policy for twenty years is regarded as China’s miracles in the world, whereas the income differential widening phenomenon has been the focus of the policymakers and researchers. The typical research of personal income allocation in regions on microeconomic data has been done in China Social Science Research Institution, and by the special income allocation research team’s household investiga- tion, we could get the useful farmer’s i…  相似文献   

15.
We used the maps of urban land-use in 1978, 1991, 1994, 2000 and 2004, and softwares such as ArcGIS, Fragstats to analyze the spatio-temporal process of urban residential space quantitatively. Some methods, such as di- rection analysis and landscape pattern analysis, were employed. The results show that: 1) the residential land grew very rapidly in Hefei from 1978 to 2004, and the increased land was distributed mainly in the central city zone surrounded by a moat; however, after 1994, it was distributed mainly outside the 1th Ring Road; 2) the expansion speeds were very different in different directions: there exists a fastest expansion of residential land in the directions of NE-NNE, SW and SSE, and a slowest one in the directions of E and SEE; 3) the residential land growth went through four stages: slow circular expansion in 1978-1991, 'axes fan wings' expansion in 1991-1994, more rapid circular expansion in 1994-2000 and 'fan-wings' expansion in 2000-2004; 4) the expansion intensity was also different in all directions in the period of 1978 to 1994, and the most was in SW and then NW; and 5) there were more and more residential land area, and the spatial agglomeration was improved increasingly.  相似文献   

16.
Urbanlandisthemaincarrierofhumandevelopment.Atthesametimelandisabasicmeansofproductivity.Urbanlandevolutionsensitivelyreflectstheprocess,tendencyandcontradictionofdevelopment.Thispaperfirsttheorizesthegeneralinterpretationonurbanlandevolution.The…  相似文献   

17.
1 Introduction It is indisputable that the urbanization has been consid- ered as an important indicator for evaluating a nation’s or a region’s modernization and industrialization. Therefore, the issue of urbanization will arouse wide and remarkable concern in both domestic and international geography in the 21st century. From a comprehensive survey of the development of urbanization all over the world, some successful modes of urbanization, such as the American mode and the Japanese mode, …  相似文献   

18.
In the modern times ,the population growth,development of industrial and agricultural production and the petroleum exploitation,brought about the unceasing expansion of artificial oasis and abrupt increase of water demand .The artificial hydraulic irrigation engineering took the place of the natural river systerm,the reservoirs took the placeof natural lakds,which in turn enhanced the space-time redistribution of surface water based on the natural evolution,and so did groundwater.The groundwater recharge reduced 26.2% in 46 years from 1950 to 1995 in the southern piedmont fold plain of Tarim Basin due to mean yearly population increase rate of 27.7‰ and associated with the water use rate increasing from 24.6% to 58.4%.At the same time the artificial water system seepage give primary play to groundwater recharge,which is up to 57.6% whilst that of the natural system reduce to 33.7%.As a result,groundwater level drop 3-5m widespread except some irrigation area and surrounding of plain reservoir.Sping water discharge also reduce about 37.6% and discharge some continuously move away to the north with the value of 0.5-1.2km in the past 40 years.  相似文献   

19.
The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.  相似文献   

20.
Based on high-resolution tree-ring data from Dulan area of Qinghai Province, five spells have been divided: the warm period before 230’s A. D., the cold period between 240’s A. D. and 800’s A. D., the significantly warm period between 810’s A. D. and 1070’s, i. e. “Medieval Warm Period”, the cold period including the “Little Ice Age” 1420’ – 1870’s and the warming period since 1880’s. All the eleven coldest or warmest decades and several great abrupt changes took place before the Middle Ages, indicating that climatic system operated in great instability during the period 150’s – 1100’s A. D., Comparison of the tree-ring data with other temperature proxy data from East China, Guliya ice core as well as the south of Qinghai-Xizang Plateau shows that such great climatic events as Eastern Han warm period between the beginning of the 1st century and the previous fifty years of the third century, the cold period covering the span of the Wei, the Jin, and the Southern and Northern dynasties, the well-known “Medieval Warm Period” as well as the “Little Ice Age” appeared in these series such as East China and Dulan area. Only the first two climatic events were recorded conspicuously in Guliya ice core while the “Medieval Warm Period” and “Little Ice Age” is far weaker. Also, the well-defined “Medieval Warm Period” didn’t occurred in the south of Qinghai-Xizang Plateau. The warming since the 20th century is the warmest in the last 2000 years Guliya ice core, the second in Dulan area and East China, but it scarcely seems pronounced in the eastern part of Qinghai-Xizang Plateau. Foundation item: Under the auspices of the projects of the Chinese Academy of Sciences (KZ951-A1-204-02 and KZ951-A1 402-03). Biography: YANG Bao(1971–), male, a native of Yanggao County, Shanxi Province, Ph. D. His research interestinclude global change.  相似文献   

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