[Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source regio...[Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source region. [Method] Water in Muyang River, lengshui River and Zizania aquatica region were sampled to measure content of pollutants in water and conclude relation between water contamination and agri- cultural non-point pollution to find the major cause of pollution. [Result] Organic pollu- tant in Muyang River was higher; N and P contents in Lengshui River were higher; the measured indices in Zizania aquatica region excessively exceeded related stan- dard. [Conclusion] The chemical fertilizers and pesticides are the toxic materials lead- ing to water contamination and constitute a major cause of pollution in Songhua Dam water-source region. Agricultural non-point pollution should be controlled in a scientific way.展开更多
The water relation and leaf gas exchange of saxoul (Haloxylon Ammodendron Bge, a C4 shrub) seedlings were studied under water stress in 2001. Saxoul seedlings maintained high transpiration when the soil moisture was a...The water relation and leaf gas exchange of saxoul (Haloxylon Ammodendron Bge, a C4 shrub) seedlings were studied under water stress in 2001. Saxoul seedlings maintained high transpiration when the soil moisture was above 11%. The seedlings were able to take up water from soil with above 6 % soil water content, which was the threshold level of soil moisture for seedlings. The relationship between transpiration and potential evaporation was linear for well-watered seedlings. The de-crease of soil water availability led to different degrees of down-regulation of stomatal conductance, leaf transpiration and net CO2 assimilation rate. The stomata played a relatively small part in determining the net CO2 assimilation rate for the same seedling. The relationship between net CO2 assimilation rate and transpiration was linear diurnally, and reduction scale of leaf transpiration was much bigger than that of net CO2 assimilation rate by waters tress treatments, therefore intrinsic wa-ter-use-efficiency increased. High evaporative demand increased the leaf transpiration but inhibited net CO2 assimilation rate. Because of the effect of VPD on transpiration in this region, the transpiration of well-watered and mild water stress seedlings becomes responsive to change in stomatal conductance over a wider range.展开更多
We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou...We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay.展开更多
La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conser...La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （Schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.展开更多
The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids spe...The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.展开更多
As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environm...As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environmental changes.In this paper,we chose northern Greenland as the research area,and constructed a Normalized Enhanced Water Index(NEWI)based on the high-precision WorldView-2 images of different phases during the ablation period in northern Greenland,followed by a statistical analysis on the spectral characteristics of the images were for the typical features in the study area.Then the fuzzy areas with similar gray values of thin sea ice and shallow ice water bodies were located,according to the distribution rules of ground objects and histogram graphic features of the images,so as to enhance the contrast of ground objects between the regions,and finally the extraction of the fine range of water bodies on the ice surface.Experimental results showed that the proposed index effectively highlighted the ice water with the water of the reflectivity difference,compared with the commonly used water index NDWI,etc.,especially in shallow water,which contributes to differentiation from other objects.The precision evaluation showed that the applied method of extraction has higher degree of refinement compared with other methods,by which the ice water can get complete ice water effectively.展开更多
The rapid economic and social developments in the Luoyuan and Lianjiang counties of Fujian Province,China,raise certain environment and ecosystem issues.The unusual phytoplankton bloom and eutrophication,for example,h...The rapid economic and social developments in the Luoyuan and Lianjiang counties of Fujian Province,China,raise certain environment and ecosystem issues.The unusual phytoplankton bloom and eutrophication,for example,have increased in severity in Luoyuan Bay （LB）.The constant increase of nutrient loads has largely caused the environmental degradation in LB.Several countermeasures have been implemented to solve these environmental problems.The most effective of these strategies is the reduction of pollutant loadings into the sea in accordance with total pollutant load control （TPLC） plans.A combined three-dimensional hydrodynamic transport-transformation model was constructed to estimate the marine environmental capacity of chemical oxygen demand （COD）.The allowed maximum loadings for each discharge unit in LB were calculated with applicable simulation results.The simulation results indicated that the environmental capacity of COD is approximately 11×l0^4tyear^-1 when the water quality complies with the marine functional zoning standards for LB.A pollutant reduction scheme to diminish the present levels of mariculture-and domestic-based COD loadings is based on the estimated marine COD environmental capacity.The obtained values imply that the LB waters could comply with the targeted water quality criteria.To meet the revised marine functional zoning standards,discharge loadings from discharge units 1 and 11 should be reduced to 996 and 3236t year^-1,respectively.展开更多
Airborne photographs can be expediently used in environmental monitoring; e.g., in the surveillance of the state of natural reserve areas, such as wetlands; or in the measurement and mapping of pollutants, such as oil...Airborne photographs can be expediently used in environmental monitoring; e.g., in the surveillance of the state of natural reserve areas, such as wetlands; or in the measurement and mapping of pollutants, such as oil spills on a lake or sea. A new and cost-effective platform of airborne remote sensing is the UAV （unmanned aerial vehicle） or drone. In this experimental work, aerial photos were made in Bakony Mountains using three UAVs equipped with small HD （high definition） cameras; resolution： 1,280 ~ 720 pixels. Within the framework of this work, a small lake was photographed, where the beginning of eutrophication was detected. This hardly can be observed from ground, however, it is visible on the aerial photos. The airborne surveillance of areas of ragweed （Ambrosia sp.） populations was also investigated. It was found that both UAVs are feasible for these tasks, and the application of these platforms for environmental monitoring is advantageous, especially in case of natural reserve areas since those are very silent and--contrary to big aircrafts and helicopters---do not disturb the ecology even in natural reserve areas and the people living there. Moreover, those could be operated in a very flexible and economic way, and the aerial photos taken are highly informative.展开更多
Rock mass unloading is an important rock engineering problem because unloading may impact the stability of a rock mass slope. Based on hydroelectric engineering principles, this study focuses on the classification of ...Rock mass unloading is an important rock engineering problem because unloading may impact the stability of a rock mass slope. Based on hydroelectric engineering principles, this study focuses on the classification of unloading zones to reflect the rock mass structure characteristics. Geological background and slope structure of the study region were considered to investigate the distribution and deformation of the unloading process. Quantitative indices were classified according to the formation mechanisms and the geological exhibition of unloading zones. The P-wave velocity(V_P), the ratio of the wave velocity(V_p) the ratio of the test P-wave velocity along the adit depth to the P-wave velocity of intact rock, the sum of joint openings every 2 meters(S_t), and the density of open joints(D_t) were calculated as quantitative indices for the rock mass unloading zone. The characteristics of the unloading zone of rock mass slopes at the dam site were successfully determined. The method of combining qualitative data with quantitative indices was found to be effective for the classification of slope unloading zones.展开更多
Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include brai...Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include braided river deposits filling erosional valleys,and sublacustrine fan,canyon and delta facies.Braided river deposits filling erosional valleys are dominated by coarse-grained lithic quartz sandstone with oblique bedding,and represent the most important sedimentation type of sandstone in the study area.Sublacustrine fan and canyon facies are mainly distributed in the Middle Oil Member.Most delta sediments are deposited in highstand system tract(HST),Because of frequent changes in base level,delta sediments are commonly eroded and rarely preserved.Sedimentary cycles are clearly reflected by lithology,sedimentary structures and well logging data,and are closely related to the changes in lacustrine level.In accordance with the basic principle of sequence subdivision,seven type-I boundaries can be recognized in Triassic strata and six type-I sequences are subdivided correspondingly.In general,lowstand system tract(LST) is well developed within stratigraphic sequences and forms the main body of reservoir sandstone in this area;highstand system tract(HST) and transgressive system tract(TST) are often eroded by upper sequences or missed,Although various factors have different influences on terrestrial sequence stratigraphy,the classical sequence stratigraphy theory proposed by VAIL can be applied to terrestrial strata.展开更多
By focusing on Guangzhou, this paper examines how different concepts of city in terms of urban-rural relationships are shaped in transforming China since 1949, and explores how they influence the way in which urban pl...By focusing on Guangzhou, this paper examines how different concepts of city in terms of urban-rural relationships are shaped in transforming China since 1949, and explores how they influence the way in which urban planning are practiced. In the pre-reform era, the city was defined as a productive space under the system of urban-rural segregation established for securing rapid industrialization. Urban planning was thus only concerned with the development of urban areas. In the 1980 s and 1990 s after the reform, institutional change and economic transformation mobilized the urban-rural linkages. The development of suburban areas was then considered by urban planning, but this consideration was a passive response to urban problems such as population explosion and water resources protection. Since the new millennium, the agenda for sustainable development and problems of uneven urban-rural development have called for the development of urban-rural integration. In this context, the city is conceptualized as a complex of mountain, city, river, farmland and sea, reconstructing the ideology of urban-rural division in defining urban development. Urban planning has therefore sought in an active way to develop a sustainable city embracing rural and natural elements, and to balance economic growth and environmental protection. It is argued that developing the concept of city as a complex of urban and rural elements contributes to the urban planning for sustainable urban development, while this conceptualization relies on the recognition of the integrated urban-rural relationship.展开更多
Based on comparison and analysis on structural cations of montmorillonite in bentonite samples collected from several typical areas in Jilin Province, relationships among type and quantity of interlayer/tetrahedral/oc...Based on comparison and analysis on structural cations of montmorillonite in bentonite samples collected from several typical areas in Jilin Province, relationships among type and quantity of interlayer/tetrahedral/octahedral cations and temperature and activation energy of removal of bound and hydroxyl water were investigated. The results show that the interlayer cations not only play decisive roles on removal temperature of bound water, but also influence dehydroxylation temperature and activation energy of montmorillonite. Type of octahedral cations also has an effect on dehydroxylation process.展开更多
基金Supported by National Natural Science Foundation of China(41501361,41401385,30871965)Open Fund of Fujian Provincial Key Laboratory of Resources and Environment Monitoring&Sustainable Management and Utilization(ZD1403)+1 种基金Fujian Natural Science Foundation(2016J01188)Scientific Research Foundation of Fuzhou University(XRC1345)
文摘[Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source region. [Method] Water in Muyang River, lengshui River and Zizania aquatica region were sampled to measure content of pollutants in water and conclude relation between water contamination and agri- cultural non-point pollution to find the major cause of pollution. [Result] Organic pollu- tant in Muyang River was higher; N and P contents in Lengshui River were higher; the measured indices in Zizania aquatica region excessively exceeded related stan- dard. [Conclusion] The chemical fertilizers and pesticides are the toxic materials lead- ing to water contamination and constitute a major cause of pollution in Songhua Dam water-source region. Agricultural non-point pollution should be controlled in a scientific way.
基金Innovation Research Pro-ject of Chinese Academy of Sciences (KZCX1-10-03), National Natural Sciences Foundation of China (90102003), and West Development Technol-ogy Project (2001BA901A42).
文摘The water relation and leaf gas exchange of saxoul (Haloxylon Ammodendron Bge, a C4 shrub) seedlings were studied under water stress in 2001. Saxoul seedlings maintained high transpiration when the soil moisture was above 11%. The seedlings were able to take up water from soil with above 6 % soil water content, which was the threshold level of soil moisture for seedlings. The relationship between transpiration and potential evaporation was linear for well-watered seedlings. The de-crease of soil water availability led to different degrees of down-regulation of stomatal conductance, leaf transpiration and net CO2 assimilation rate. The stomata played a relatively small part in determining the net CO2 assimilation rate for the same seedling. The relationship between net CO2 assimilation rate and transpiration was linear diurnally, and reduction scale of leaf transpiration was much bigger than that of net CO2 assimilation rate by waters tress treatments, therefore intrinsic wa-ter-use-efficiency increased. High evaporative demand increased the leaf transpiration but inhibited net CO2 assimilation rate. Because of the effect of VPD on transpiration in this region, the transpiration of well-watered and mild water stress seedlings becomes responsive to change in stomatal conductance over a wider range.
基金Supported by the National Basic Research Program of China (973 Program) (No. 2011CB403601)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-Q07-01)+2 种基金the External Cooperation Program of Chinese Academy of Sciences (No. GJHZ200808)the National Natural Science Foundation of China (No. 40876083)the Ocean Public Welfare Scientific Research Project, State Oceanic Administration of China (No. 201005014)
文摘We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay.
文摘La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （Schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.
基金the Shandong Foundation of Sciences(No.Y2000D04) the National Key Basic Research Program from the Ministry of Science and Technology of China(No.G19990437).
文摘The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.
基金supported by the 2020 Key project of Science and Technology for Economy(Grant No. SQ2020YFF0426316)。
文摘As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environmental changes.In this paper,we chose northern Greenland as the research area,and constructed a Normalized Enhanced Water Index(NEWI)based on the high-precision WorldView-2 images of different phases during the ablation period in northern Greenland,followed by a statistical analysis on the spectral characteristics of the images were for the typical features in the study area.Then the fuzzy areas with similar gray values of thin sea ice and shallow ice water bodies were located,according to the distribution rules of ground objects and histogram graphic features of the images,so as to enhance the contrast of ground objects between the regions,and finally the extraction of the fine range of water bodies on the ice surface.Experimental results showed that the proposed index effectively highlighted the ice water with the water of the reflectivity difference,compared with the commonly used water index NDWI,etc.,especially in shallow water,which contributes to differentiation from other objects.The precision evaluation showed that the applied method of extraction has higher degree of refinement compared with other methods,by which the ice water can get complete ice water effectively.
基金supported by the Science Fund Projects of Shandong Province (ZR2010DM005)the State Ocean Administration of China ‘908’ Foundation (908-02-02-03)the Science and Technology Development Plan of Qingdao (11-2-3-66-nsh and 11-2-1-18-hy)
文摘The rapid economic and social developments in the Luoyuan and Lianjiang counties of Fujian Province,China,raise certain environment and ecosystem issues.The unusual phytoplankton bloom and eutrophication,for example,have increased in severity in Luoyuan Bay （LB）.The constant increase of nutrient loads has largely caused the environmental degradation in LB.Several countermeasures have been implemented to solve these environmental problems.The most effective of these strategies is the reduction of pollutant loadings into the sea in accordance with total pollutant load control （TPLC） plans.A combined three-dimensional hydrodynamic transport-transformation model was constructed to estimate the marine environmental capacity of chemical oxygen demand （COD）.The allowed maximum loadings for each discharge unit in LB were calculated with applicable simulation results.The simulation results indicated that the environmental capacity of COD is approximately 11×l0^4tyear^-1 when the water quality complies with the marine functional zoning standards for LB.A pollutant reduction scheme to diminish the present levels of mariculture-and domestic-based COD loadings is based on the estimated marine COD environmental capacity.The obtained values imply that the LB waters could comply with the targeted water quality criteria.To meet the revised marine functional zoning standards,discharge loadings from discharge units 1 and 11 should be reduced to 996 and 3236t year^-1,respectively.
文摘Airborne photographs can be expediently used in environmental monitoring; e.g., in the surveillance of the state of natural reserve areas, such as wetlands; or in the measurement and mapping of pollutants, such as oil spills on a lake or sea. A new and cost-effective platform of airborne remote sensing is the UAV （unmanned aerial vehicle） or drone. In this experimental work, aerial photos were made in Bakony Mountains using three UAVs equipped with small HD （high definition） cameras; resolution： 1,280 ~ 720 pixels. Within the framework of this work, a small lake was photographed, where the beginning of eutrophication was detected. This hardly can be observed from ground, however, it is visible on the aerial photos. The airborne surveillance of areas of ragweed （Ambrosia sp.） populations was also investigated. It was found that both UAVs are feasible for these tasks, and the application of these platforms for environmental monitoring is advantageous, especially in case of natural reserve areas since those are very silent and--contrary to big aircrafts and helicopters---do not disturb the ecology even in natural reserve areas and the people living there. Moreover, those could be operated in a very flexible and economic way, and the aerial photos taken are highly informative.
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 41521002)the National ScienceTechnology Support Program of China (Grant No. 2015BAK09B01)the Key Project of theNational Natural Science Foundation of China (Grant No. 41130745)
文摘Rock mass unloading is an important rock engineering problem because unloading may impact the stability of a rock mass slope. Based on hydroelectric engineering principles, this study focuses on the classification of unloading zones to reflect the rock mass structure characteristics. Geological background and slope structure of the study region were considered to investigate the distribution and deformation of the unloading process. Quantitative indices were classified according to the formation mechanisms and the geological exhibition of unloading zones. The P-wave velocity(V_P), the ratio of the wave velocity(V_p) the ratio of the test P-wave velocity along the adit depth to the P-wave velocity of intact rock, the sum of joint openings every 2 meters(S_t), and the density of open joints(D_t) were calculated as quantitative indices for the rock mass unloading zone. The characteristics of the unloading zone of rock mass slopes at the dam site were successfully determined. The method of combining qualitative data with quantitative indices was found to be effective for the classification of slope unloading zones.
基金Project(2008ZX05002-005) supported by the State Major Special Science and Technology Foundation of China
文摘Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include braided river deposits filling erosional valleys,and sublacustrine fan,canyon and delta facies.Braided river deposits filling erosional valleys are dominated by coarse-grained lithic quartz sandstone with oblique bedding,and represent the most important sedimentation type of sandstone in the study area.Sublacustrine fan and canyon facies are mainly distributed in the Middle Oil Member.Most delta sediments are deposited in highstand system tract(HST),Because of frequent changes in base level,delta sediments are commonly eroded and rarely preserved.Sedimentary cycles are clearly reflected by lithology,sedimentary structures and well logging data,and are closely related to the changes in lacustrine level.In accordance with the basic principle of sequence subdivision,seven type-I boundaries can be recognized in Triassic strata and six type-I sequences are subdivided correspondingly.In general,lowstand system tract(LST) is well developed within stratigraphic sequences and forms the main body of reservoir sandstone in this area;highstand system tract(HST) and transgressive system tract(TST) are often eroded by upper sequences or missed,Although various factors have different influences on terrestrial sequence stratigraphy,the classical sequence stratigraphy theory proposed by VAIL can be applied to terrestrial strata.
基金Under the auspices of Program of International Cooperation and Exchanges of National Natural Science Foundation of China(No.41320104001)Key Program of National Natural Science Foundation of China(No.41130747)
文摘By focusing on Guangzhou, this paper examines how different concepts of city in terms of urban-rural relationships are shaped in transforming China since 1949, and explores how they influence the way in which urban planning are practiced. In the pre-reform era, the city was defined as a productive space under the system of urban-rural segregation established for securing rapid industrialization. Urban planning was thus only concerned with the development of urban areas. In the 1980 s and 1990 s after the reform, institutional change and economic transformation mobilized the urban-rural linkages. The development of suburban areas was then considered by urban planning, but this consideration was a passive response to urban problems such as population explosion and water resources protection. Since the new millennium, the agenda for sustainable development and problems of uneven urban-rural development have called for the development of urban-rural integration. In this context, the city is conceptualized as a complex of mountain, city, river, farmland and sea, reconstructing the ideology of urban-rural division in defining urban development. Urban planning has therefore sought in an active way to develop a sustainable city embracing rural and natural elements, and to balance economic growth and environmental protection. It is argued that developing the concept of city as a complex of urban and rural elements contributes to the urban planning for sustainable urban development, while this conceptualization relies on the recognition of the integrated urban-rural relationship.
文摘Based on comparison and analysis on structural cations of montmorillonite in bentonite samples collected from several typical areas in Jilin Province, relationships among type and quantity of interlayer/tetrahedral/octahedral cations and temperature and activation energy of removal of bound and hydroxyl water were investigated. The results show that the interlayer cations not only play decisive roles on removal temperature of bound water, but also influence dehydroxylation temperature and activation energy of montmorillonite. Type of octahedral cations also has an effect on dehydroxylation process.
