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Influence of environment and substrate quality on the decomposition of wetland plant root in the Sanjiang Plain,Northeast China 被引量:17
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作者 GUO Xuelian LU Xianguo +1 位作者 TONG Shouzheng DAI Guohua 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第12期1445-1452,共8页
The litterbag method was used to study the decomposition of wetland plant root in three wetlands along a water level gradient in the Sanjiang Plain,Northeast China.These wetlands are Calamagrostis angustifolia(C.aa),C... The litterbag method was used to study the decomposition of wetland plant root in three wetlands along a water level gradient in the Sanjiang Plain,Northeast China.These wetlands are Calamagrostis angustifolia(C.aa),Carex meyeriana(C.ma)and Carex lasiocarpa (C.la).The objective of our study is to evaluate the influence of environment and substrate quality on decomposition rates in the three wetlands.Calico material was used as a standard substrate to evaluate environmental influences.Roots native to each we... 展开更多
关键词 wetland plant root DECOMPOSITION environment quality substrate quality Sanjiang Plain
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Comprehensive Evaluation on Urban Sustainable Development of Harbin City in Northeast China 被引量:4
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作者 CAI Chunmiao SHANG Jincheng 《Chinese Geographical Science》 SCIE CSCD 2009年第2期144-150,共7页
It is an effective way in realizing urban coordinated and sustainable development to establish a series of in- dicators and to evaluate urban environmental and socioeconomic development. According to the characteristi... It is an effective way in realizing urban coordinated and sustainable development to establish a series of in- dicators and to evaluate urban environmental and socioeconomic development. According to the characteristics of Harbin City in Northeast China, an indicator system including five subsystems and 37 indicators was established for comprehensive evaluation on urban sustainable development. The development indexes of all urban subsystems and complex system were calculated quantitatively using the comprehensively integrated methods composed of Principle Component Analysis, Analytic Hierarchy Process and weighed index method, and then the comprehensive level of ur- ban sustainable development and the degree of urban interior coordination were analyzed. The results indicated that 1) the overall urban development presented an uptrend, however, the interior development was not well balanced from 1996 to 2006; 2) the development in each subsystem presented a strong fluctuation; and 3) the development in re- sources subsystem showed a downtrend. Based on those results, the suggestions of urban sustainable development were put forward at the end. 展开更多
关键词 sustainable development indicator system comprehensive evaluation Harbin City
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Establishment and Application of Urbanization Strategic Environ-mental Assessment Integration Technology System 被引量:3
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作者 ZHAO Yan SHANG Jincheng +1 位作者 XU Ling SONG Tao 《Chinese Geographical Science》 SCIE CSCD 2008年第2期184-192,共9页
Urbanization strategic environmental assessment (SEA) is an effective instrument to enhance the harmo-nious development of urban complex system, integrating of environment and development in decision-making. Ur-baniza... Urbanization strategic environmental assessment (SEA) is an effective instrument to enhance the harmo-nious development of urban complex system, integrating of environment and development in decision-making. Ur-banization strategic environmental assessment integration technology system (SEA-ITS) is composed of "3S" (RS, GIS and GPS), environmental expert system and environmental model system, coupling with appropriate SEA working process closely. In this paper, the structure and components of SEA-ITS are analyzed based on Chinese characteristics, meanwhile methods to fulfill the following system functions are discussed: urbanization SEA in-quiring, analysis, discrimination, assessment, prediction, decision-making and output. Moreover, methods and tech-nologies employed in different urbanization SEA hierarchies are summarized. As a case study, urbanization SEA-ITS is applied in Changchun City to solving complex real problems. Methods such as system dynamics and grey cluster are adopted to achieve the environmental impact assessment on the eco-industrial system planning. It is revealed that the system designed is capable of reflecting the dynamic behavior of eco-industrial system under different sce-narios, meanwhile accomplishing strategy optimization and supplying scientific reference. The 4th strategy, namely concerning on economy increase and its interaction with science, technology and environment progress, would have the best efficiency. Further, more attention should be paid to the secondary development of integration techniques and function modification system of urbanization SEA-ITS. 展开更多
关键词 environmental expert system (EES) urbanization strategic environmental assessment integration technology system (SEA-ITS) environmental technology system (ETS) system dynamics grey cluster
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Element and mineral characterization of dust emission from the saline land at Songnen Plain, Northeastern China 被引量:1
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作者 CHEN Bing KITAGAWA Hiroyuki +3 位作者 HU Ke JIE Dongmei YANG Junpeng LI Jingmin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第10期1363-1370,共8页
Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songn... Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain (SSL), Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles (〈 10 μm in diameter) on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions. 展开更多
关键词 element geochemistry individual particle analysis Asian dust dust storm saline soil land degradation
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Morphological Characteristics and Environmental Implications of Phytoliths in Topsoils from Different Vegetation Zones on Northern Slope of Changbai Mountains,China
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作者 QIAO Zhihe JIE Dongmei +2 位作者 LIU Hongmei GE Yong ZHANG Hongyan 《Chinese Geographical Science》 SCIE CSCD 2010年第6期506-512,共7页
The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from differen... The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline. 展开更多
关键词 topsoil phytolith TIMBERLINE environmental implication vertical vegetation zones Changbai Mountains
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Influence of litter layer on ecological environment in northeastern leymus chinensis grassland of China
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作者 WANG Yong GUO Ji-xun 《Journal of Life Sciences》 2007年第1期40-48,共9页
In this paper, we adopted simulation method to discuss influences of litter layer on plants habitat in grassland. Results indicated that ground surface evaporation, soil moisture, surface temperature, soil pH, soil bu... In this paper, we adopted simulation method to discuss influences of litter layer on plants habitat in grassland. Results indicated that ground surface evaporation, soil moisture, surface temperature, soil pH, soil bulk density and soil porosity were all strongly related to the litter quantity. Potassium (K) and organic materials in the soil covered by litter layer were higher than those in the soil uncovered by litter layer. With 100 g.ln-z increase of litter, the percentage of organic materials increased by 17.9%, nitrogen (N) increased by 7.6%, phosphor (P) increased by 26.4%, and K increased by 3.8%. With the litter accumulation amounting up to 600 g-m-2, the percentage of organic materials increased by 1.8 times, N increased by 81.5%, P increased by 1.8 times and K increased by 26.4%. According to the expected coefficient method of optimization, a mathematical model was established about the optimal accumulation quantity of litter. 展开更多
关键词 litter layer Leymus chinensis grassland environmental factor soil nutrient
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CAUSES AND CONTROL COUNTERMEASURES OF EUTROPHICATION IN CHAOHU LAKE, CHINA 被引量:26
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作者 SHANG Guang-ping SHANG Jin-cheng 《Chinese Geographical Science》 SCIE CSCD 2005年第4期348-354,共7页
Chaohu Lake, located in the central Anhui Province, is one of the five largest fresh lakes in China. Now it is one of the three most eutrophication lakes in China. The deterioration of its water quality has influenced... Chaohu Lake, located in the central Anhui Province, is one of the five largest fresh lakes in China. Now it is one of the three most eutrophication lakes in China. The deterioration of its water quality has influenced the sustainable development of society, economy and environment of Hefei City, the capital of Anhui Province. A series of measures have been carried out to control its eutrophication, but it is still serious. On the basis of the lake water quality data from 1984 to 2003, the causes of the eutrophication of Chaohu Lake are analyzed. Studies indicated that the suitable natural conditions and human activities played a crucial role in the process of the eutrophication of Chaohu Lake. A great amount of industrial, agricultural and domestic sewage discharged into the lake is the main cause of eutrophication in the lake. Land use, soil erosion and shoreline collapse destroyed the watershed eco-environment and the terrestrial ecosystem of Chaohu Lake. And the building of Yuxi Gate extends the sluggish of the nutritious substance and speeds up the process of the eutrophication. From the view of systematic engineering and watershed ecology, a series of the countermeasures have been put forward to control the eutrophication. 展开更多
关键词 causes of eutrophication eutrophication control non-engineering measures watershed management Chaohu Lake
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Dynamics and Relationships of Ca,Mg,Fe in Litter,Soil Fauna and Soil in Pinus koraiensis-Broadleaf Mixed Forest 被引量:21
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作者 SONG Bo YIN Xiuqin +1 位作者 ZHANG Yu DONG Weihua 《Chinese Geographical Science》 SCIE CSCD 2008年第3期284-290,共7页
The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter (Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, ... The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter (Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, Betula costata, and mixed litter), soil in humus horizon (0--5cm) and soil horizon (5-20cm), and soil macrofauna (Oligochaeta, Geophiloporpha and Juliformia) from 2001 to 2002. The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index (El). The results indicate that dynamic changes of various litters are very complicated. The contents of Fe in each kind of litter increase firstly, and then decrease in the study period. The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter, and the mixed litter is in the middle level, but the differences among them are not significant. The contents of Mg and Fe in humus are higher than those in soil, but the contents of Ca in soil are higher than that in humus. The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter. The diplopod presented obvious enrichment of Ca and Mg (E1〉1), but it does not significantly enrich Fe. Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra, but E1〈1. Soil fauna can make great influences on the material cycle of the subsystems. 展开更多
关键词 soil fauna litter decomposition macro-element cycle Liangshui Natural Reserve
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Transformation of Carbon and Nitrogen by Earthworms in the Decomposition Processes of Broad-leaved Litters 被引量:14
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作者 DONG Weihua YIN Xiuqin 《Chinese Geographical Science》 SCIE CSCD 2007年第2期166-172,共7页
Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total ni... Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total nitrogen (N) in the broad-leaved litters ingested by earthworms was researched by means of a laboratory experiment. Experimental samples were collected from broad-leaved Korea Pine mixed forest in Liangshui National Natural Reserve (47°10′50″N, 128°53′20″E) in the northeastern Xiao Hinggan Mountains of Northeast China. The contents of organic C and total N in earthworms, leaf litters and earthworm faeces were analyzed. Results show that the organic C content was in the fol- lowing order: leaf litters>faeces>earthworms, while total N content was contrary to that of the organic C. The organic C contents in the different leaf litters were in the following order: Tilia amurensis>Betula costata>Acer mono, whereas the total N contents in the different leaf litters were: Betula costata>Tilia amurensis>Acer mono. The contents of organic C and total N in the faeces from the different leaf litters were almost consistent with the contents of the leaf litters. After the leaf litters were ingested by earthworms, the organic C, which was transformed to increase earthworms' weights, ac- counted for 3.90%-13.31% of the total ingestion by earthworms, while that in the earthworm faeces accounted for 6.14%-13.70%. The transformed organic C through the other metabolism (e.g., respiration) of earthworms accounted for 75.04%-89.92%. The ingested organic C by earthworms was mostly used for metabolic activities. The N ingested by earthworms was less than organic C. It is estimated that 37.08% of total N was transformed to increase the earthworm's weight, 19.97% into earthworm faeces and 47.86% for the consumption of the earthworm's activities. The earthworms not only increased the content of organic C and total N in the soil, but also decreased the values of C/N in the soil and leaf litters. Earthworms play a major role in the leaf litters' decomposition and transformation. 展开更多
关键词 broad-leaved litters organic carbon total nitrogen EARTHWORM C transformation N transformation
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Land Use Changes in Northeast China Driven by Human Activities and Climatic Variation 被引量:11
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作者 WANG Zongming LIU Zhiming +5 位作者 SONG Kaishan ZHANG Bai ZHANG Sumei LIU Dianwei REN Chunying YANG Fei 《Chinese Geographical Science》 SCIE CSCD 2009年第3期225-230,共6页
Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this p... Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change. 展开更多
关键词 land use change remote sensing climate warming Northeast China
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Alternatives of Strategic Environmental Assessment for Road Traffic Development Planning——Case of Changchun City,China 被引量:4
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作者 CHEN Chong XU Yex +1 位作者 SHANG Jincheng Gordon HUANG 《Chinese Geographical Science》 SCIE CSCD 2009年第1期25-36,共12页
On analyzing the achievement of the goal in the modem urban road traffic development planning, the alternative of Strategic Environmental Assessment for urban traffic planning should include the basic scheme, the exte... On analyzing the achievement of the goal in the modem urban road traffic development planning, the alternative of Strategic Environmental Assessment for urban traffic planning should include the basic scheme, the extended scheme and the environmental protection scheme. This study from different perspectives designed the alternatives for Changchun's county-level road and urban road system planning, and used the method of System Dynamics to simulate, optimize and analyze those alternatives. Thereafter, some methods including the correlation function method were used to comprehensively assess and rank those alternatives for recommending two best alternatives with the consideration to the indicators, such as the total emission amount of CO, the total emission amount of nitrogen oxides, the noise value, the road construction cost, the fossil oil consumption and the traffic capacity. The result showed that the study would provide substantial supports for decision-makers to make more scientific decisions and promote the sustainable urban traffic in Changchun City. 展开更多
关键词 road traffic traffic planning Strategic Environmental Assessment (SEA) correlation function Changchun City
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Regional Evolution Features and Coordinated Development Strategies for Northeast China 被引量:3
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作者 MEI Lin XU Xiaopo CHEN Mingxiu 《Chinese Geographical Science》 SCIE CSCD 2006年第4期378-382,共5页
Northeast China, as the most important production base of agriculture, forestry, and livestock-breeding as well as the old industrial base in the whole country, has been playin a key role in the construction and deve... Northeast China, as the most important production base of agriculture, forestry, and livestock-breeding as well as the old industrial base in the whole country, has been playin a key role in the construction and development of China's economy. However, after the policy of reform and open-up was taken in China. the economic development speed and efficiency ofthis area have turned to be evidently lower than those of coastal area and the national average level as well, which is so-called 'Northeast Phenomenon' and 'Neo-Northeast Phenomenon'. In terms of those phenomena, this paper firstly reviews the spatial and temporal features of the regional evolution of this area so as to unveil the profound forming causes of 'Northeast Phenomena' and 'Neo-Northeast Phenomena'. And then the paper makes a further exploration into the status quo of this region and its forming causes by analyzing its economy gross, industrial structure, product structure, regional eco-categories, etc. At the end of the paper, the authors put forward the basic coordinated development strategies for Northeast China. namely we can revitalize this area by means of adjustment of economic structure, regional coordination, planning urban and rural areas as a whole, institutional innovation, etc. 展开更多
关键词 regional evolution spatial-temporal feature coordinated development strategy Northeast China
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Spatio-temporal Variation of Landscape Heterogeneity under Influence of Human Activities in Xiamen City of China in Recent Decade 被引量:3
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作者 HUANG Yixiong YIN Xiuqin +5 位作者 YE Gongfu LIN Jiemin HUANG Ru WANG Na WANG Liang SUN Yue 《Chinese Geographical Science》 SCIE CSCD 2013年第2期227-236,共10页
Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activ... Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern. 展开更多
关键词 landscape heterogeneity human impact index human activities Xiamen City
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Quantitative Relationship Between Multi-Angle Polarized Reflectance and BRDF of Rock 被引量:5
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作者 ZHAO Yun-sheng WU Tai-xia +1 位作者 LIU Bao LUO Yang-jie 《Journal of China University of Mining and Technology》 EI 2005年第3期192-196,共5页
The traditional remote sensing mainly detects the ground vertically to obtain the 2D information but it is hard to get adequate parameters for the quantitative remote sensing to invert land features. The multi-angle o... The traditional remote sensing mainly detects the ground vertically to obtain the 2D information but it is hard to get adequate parameters for the quantitative remote sensing to invert land features. The multi-angle observation can get more detailed and reliable 3D structural parameters of targets, so it makes the quantitative remote sensing applicable. During the process of reflecting, scattering and transmitting the electromagnetic wave, minerals and rocks could reveal the polarized features related to the nature of themselves. Therefore, it has become a new approach of quantitative remote sensing to detect multi-angle polarized information of minerals and rocks. In respect that the polarized reflectance always goes with the bidirectional one, we can obtain the 3D spatial distribution of targets by a polarized means together with detecting its bi-directional reflectance. From the perspective of multi-angle polarized remote sensing mechanism, the quantitative relationship between multi-angle polarized reflectance and the BRDF is studied in this paper. And it is testified that the bi-directional reflectance, polarized reflectance of 45° and the mean value of polarized reflectance are equal to that of the corresponding azimuth angle, zenith angle, detection angle and detection channels in 27t space by experiment. 展开更多
关键词 ROCK Multi-angle Polarized reflectance BRDF Quantitative remote sensing
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Controllable Synthesis of Titania Nanocrystals with Different Morphologies and Application to the Degradation of Phenol 被引量:1
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作者 CHEN Da-wei SHI Jin-e YAN Ji-chang WANG Yue-hong YAN Fu-cheng SHANG Shu-xia XUE Jing 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第3期362-366,共5页
Titania nanocrystals with different morphologies were prepared using the hydrothermal method via controlling the pH values of solution, the ratio of reactants, temperature, and time of the hydrothermal reaction. The e... Titania nanocrystals with different morphologies were prepared using the hydrothermal method via controlling the pH values of solution, the ratio of reactants, temperature, and time of the hydrothermal reaction. The experimental results showed that uniform rod-like titania particles with an average aspect ratio of 6:1 could be obtained under the conditions of pH=11, n(TBOT):n(TEA)=1:2, hydrothermal treatment at 150 °C for 24 h. When pH〈10, spherical titania nanocrystals could be obtained; with increasing the pH value, the diameter became smaller. Finally, the smallest size of the particles could reach 7 nm. Nanocrystals with uniformly well-dispersed and perfect crystallographic form were obtained via the above method. Phenol was used as the degradation model for testing the photocatalytical activity of the titania nanocrystals with different morphologies. 展开更多
关键词 TiO2 Hydrothermal synthesis Nanoparticle ANATASE Phenol degradation
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A GIS-based Tupu Analysis of Dynamics of Saline-alkali Land in Western Jilin Province 被引量:1
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作者 REN Chunying ZHANG Bai +3 位作者 WANG Zongming SONG Kaishan LIU Dianwei LIU Zhiming 《Chinese Geographical Science》 SCIE CSCD 2007年第4期333-340,共8页
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 wes... 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. 展开更多
关键词 Tupu saline-alkali land GIS Jilin Province
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Areal differentiation of virtual water for agricultural products and its effect on regional agricultural structure adjustment in China: 1995-2007 被引量:3
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作者 QIN Li-jie ZONG Sheng-wei CHANG Yong-zhi 《Ecological Economy》 2010年第1期80-87,共8页
With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The... With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security. 展开更多
关键词 Virtual water Areal differentiation Adjustment of agricultural structure
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Spatial Structure and Location of Multi-national Corporations in China—A Case Study of Samsung
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作者 WANG Dan WANG Shijun 《Chinese Geographical Science》 SCIE CSCD 2007年第4期297-303,共7页
The investment of Samsung Electronics in China is divided into three types: production companies, sales companies and R&D institutions. Based on an analysis of the spatial structure of Samsung's three types of inve... The investment of Samsung Electronics in China is divided into three types: production companies, sales companies and R&D institutions. Based on an analysis of the spatial structure of Samsung's three types of investment and parent company, it is put forward that regional bias exists during the operation of a multi-national corporation (MNC) in China, i.e., regional biases of technology, price, sales as well as decision-making. Front office and back ofrice, two terms related closely with the location of modern MNCs, are defined and locational principles of each are studied. It is pointed out that production companies and R&D institutions belong to back office, while sales company falls into the type of front office. Based on a summarization on the spatial distribution of production companies, sales companies and R&D institutions, the locational principles of front office and back office are then applied in explaining the location of Samsung's operating entities in China. By analyzing the spatial structure and locational principles of Samsung, a typical MNC in China, this paper aims to understand the internal operating mechanism of modern MNCs and then bring assistance to related policies to cope with those problems about MNCs that have attracted growing attention in recent years. 展开更多
关键词 multi-national corporation (MNC) regional bias front office back office SAMSUNG
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Evaluation and QSAR Study of Joint Toxicity of Substituted Phenols and Cadmium to Photobacterium phosphoreum
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作者 SU Li-min YUAN Xing MU Chun-fang YAN Ji-chang ZHAO Yuan-hui 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第3期281-284,共4页
The single toxicity of cadmium(Cd) or 9 substituted phenols to Phtobacterium phosphoreum was determined, respectively. The results indicate that the single toxicity was related to group variety, group sum and substi... The single toxicity of cadmium(Cd) or 9 substituted phenols to Phtobacterium phosphoreum was determined, respectively. The results indicate that the single toxicity was related to group variety, group sum and substitutive positions. On the basis of single toxicity, the joint toxicity of Cd and 9 substituted phenols was measured. The result indicates that the joint toxicity was basically a simple addition of the single toxicity of them or close to simple addition of the single toxicity of them. QSAR equations were built from the joint toxicity and molecular structural descriptors of substituted phenols under the different Cd concentrations. It was shown that the joint toxicity under different Cd concentrations was related to the identical descriptors, the logarithm of n-octanol/water partition coefficient(lgP) and the heat of formation(△Hf), with R2=0.855, 0.878 and 0.780, respectively. Good agreement between the predicted and observed values was found with R2=0.837. 展开更多
关键词 QSAR Photobacterium phosphoreum Synergism ANTAGONISM
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Effects of temperature and discharge parameters on ozone concentration of negative corona discharge
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作者 WANG Hai-jun SHENG Lian-xi XU De-xuan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第6期796-799,共4页
The relationship of the ozone generation and the heating power, corona wire surface temperature, discharge electrode and netting electrode was studied during the negative corona discharge. The experimental results sho... The relationship of the ozone generation and the heating power, corona wire surface temperature, discharge electrode and netting electrode was studied during the negative corona discharge. The experimental results showed that the ozone concentration reduced with applied voltage decrease. With heating power increase, the ozone concentration of unit current decreased at exponential rate and it almost change no longer over 0.40 W. Under given temperature, the lower the applied voltage was, the smaller the ozone concentration was; while under given applied voltages, only over 11 kV could decrease with the surface temperature increase. The ozone concentration decreased with the lengthening of corona wire, and could reduced to 10 ppb under experimental condition of 14.2 kV; it also decreased with the shortening of wire diameter, and could decrease 67% at best in the given condition. Moreover, it decreased with the increasing size of netting electrode mesh. At the anion current of 1.65 μΑ, the ozone concentration of 5.0×5.0 cm 2 is only 41% of that of 3.3×3.3 cm 2. 展开更多
关键词 OZONE negative corona discharge anion current
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