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161.
通过X射线荧光、红外光谱和X射线衍射等检测方法分析了延庆硅化木的矿物学特征.结果表明:2个不同植物种属但在同一埋藏地形成硅化木标本成因相似,其颜色与所含元素种类及含量密切相关.X射线衍射分析表明,不同颜色和植物种属的硅化木主要组成物相一致,为SiO2,其他矿物极其微量.2个硅化木标本的红外吸收谱带基本一致,均显示典型的石英质玉石红外吸收光谱,且含有少量吸附水.偏光显微镜下显示2个硅化木标本的主要矿物成分均为隐晶质石英.延庆土城子组硅化木的沉积环境为较浅的湖沼沉积,当时处于半干旱-半湿润的气候条件下,并伴随火山活动.  相似文献   
162.
提出了一种多目标禁忌搜索算法来实现土地整理备选区片的自动划分,阐述了其流程和关键问题。以武汉市江夏区高产农田整理分区为例进行实证研究,验证了模型的有效性。  相似文献   
163.
SR28、SR29地热对井位于天津市东丽区,处于沧县隆起之大小东庄凸起的西缘,沧东断裂带附近,山岭子地热异常区中心.SR28、SR29地热对井采用中元古界蓟县系雾迷山组热储层作为开采和回灌目的层.根据地热水化学分析结果分析了地热水的水文地球化学特征,认为:SR28、SR29地热水属于含岩盐地层溶虑的陆相沉积水;雾迷山组碳酸盐地层为地热水的储水层,地热水来源于外源水流经上层灰岩地层的补给;SR28、SR29地热水属于未污染的天然水、微腐蚀型水,不结CaCO_3 垢和CasO_4·2H_20垢,有SiO_2垢生成的可能.  相似文献   
164.
张春山    何淑军  辛鹏  孙炜锋    谭成轩    吴树仁    王涛  刘鑫 《地质通报》2009,28(08):1053-1063
在渭滨区地质灾害详细调查的基础上,通过统计分析确定了各类地质灾害危险性和易损性的主要影响因素,采用模型方法和定性评价方法分别进行了地质灾害的危险性评价和易损性评价,在此基础上进行了地质灾害风险评价。渭滨区地质灾害类型主要为滑坡、崩塌、泥石流3种,共发育地质灾害隐患点123个,其中有16个点直接威胁人民的生命和财产。分别统计了渭滨区各乡镇地质灾害的多少和危害程度,总结了区域内地质灾害的分布特征,分析了地质灾害的形成条件,建立了地质灾害风险评价的指标体系,确定了地质灾害危险性、易损性和风险的判别标准,进行了地质灾害风险性评价与区划。共划分为极高风险区、高风险区、中风险区、低风险区和极低风险区5个等级。  相似文献   
165.
At the study area of Xigu District in Lanzhou City, using RS & GIS as tools we apply Diversity, Dominance, Fragmentation, Isolation and so on to study the quantitative, fractal and spatial characters of landscapes structures in the four sub-regions divided by the morphological features. Using the Fractal Theory to establish the fractal structure models, we analyze the complexity and stability of various landscapes distribution with fractal dimension value. The spatial distribution characteristics of landscape mosaic structure are also expounded. At the end of the paper we discuss the relevant problems on the main factors which control and effect on the spatial pattern of landscapes as well as on landscape optimization and management. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 40171069). Biography: XU Jian-hua (1965 - ), male, a native of Gansu province, professor. His research interest includes Geo-computation and GIS.  相似文献   
166.
The Okiep Copper District, part of the 1.2–1.0 Ga high-grade terrane in western Namaqualand, is composed of a mid-Proterozoic supracrustal sequence and several pre- to post-orogenic intrusive suites affected by two high-grade events (M2a/M2b, M3) of Kibaran and one low-grade event (M4) of Pan-African age. Peak assemblages in quartz-bearing pelites are characterized either by garnet+cordierite coexisting with sillimanite/biotite, or by biotite+sillimanite±garnet; a difference controlled by bulk composition and variation in water activities (0.1–0.7) during dehydration melting. Maximum P–T conditions were reached during M2a coevally with the major deformational event (D2a) and are estimated at 750–820  °C and 5–6  kbar. A counterclockwise P–T  path is indicated by regionally occurring pseudomorphs of sillimanite after andalusite and by prograde reaction textures preserved as relics in M2a porphyroblasts. Two stages of retrograde metamorphism are distinguished: M2a garnet+cordierite-bearing assemblages were retrogressed to biotite+sillimanite+quartz (M2b) along discontinuous foliation planes and shear zones (D2b). Retrograde M3 corona assemblages formed at similar P–T  conditions (580–660  °C and 5.8±0.5  kbar) to the M2b assemblages but M3 crystallization postdates penetrative D2 deformation, intrusion of 1.06 Ga granitoids and formation of associated W–Mo deposits. It is concluded that: (a) Kibaran high-grade metamorphism in the Okiep Copper District is thermally punctuated and (b) reaction textures documenting apparent isobaric cooling of this low- P high- T  terrane must be interpreted with caution.  相似文献   
167.
1IN TR O D U C TIO NEcologicaldem onstration area (ED A )isan authoritativenom ination by N ational Environm ental Protection A d-m inistration ofC hina,w hich firstbegan itsexperim entalconstruction ofED A in 1995 and w asprom ulgated "N a-tionalExam ina…  相似文献   
168.
BOOK REVIEWS     
Book Reviewed in this article: Geography and the Third World. International Seminar, 14–18 May 1980, Kuala Lumpur, Malaysia . Ishmail Ahmad and Jamaluddin Md Jahi, eds. The Growth Dilemma: Residents' Views and Local Population Change in the United States . Mark Baldassare. Sport and Place: A Geography of Sport in England, Scotland & Wales . John Bale. The Deindustrialization of America: Plant Closings, Community Abandonment, and the Dismantling of Basic Industry . Barry Bluestone and Bennett Harrison. Selected Essays 1963–1975: Carl O. Sauer . Bob Callahen, ed. Housing and Planning in the Countryside . G. Clark. Conflict, Politics and the Urban Scene . Kevin R. Cox and R. J. Johnston, eds. Thematic Maps: Their Design and Production . David J. Cuff and Mark T. Mattson. Wine: A Geographic Appreciation . Harm Jan de Blij. USSR in Maps . J. C. Dewdney. Political Geography: A Contemporary Perspective . Ramesh D. Dikshit. Rethinking Human Adaptation . Rada Dyson-Hudson and Michael A. Little, eds. Sacred Sands: The Struggle for Community in the indiana Dunes . J. Ronald Engel. Geography of the Biosphere . A. Furley and Walter W. Newey. Disaster and Reconstruction . Robert Geipel. Glasgow: The Making of a City . Andrew Gibb. Design for Arid Regions . Giden S. Golany, ed. Urbanization and Cancer Mortality: The United States Experience, 1950–1975 . Michael R. Greenberg. Geology in the Nineteenth Century: Changing Views of a Changing World . Mott T. Greene. Colonización y Destrucción de Bosques en Panamá . Stanley Heckadon Moreno and Alberto McKay, eds. Urban Geography: A First Approach . David T. Herbert and Colin J. Thomas. The Visual and Spatial Structure of Landscapes . Tadahiko Higuchi. Climate from Tree Rings . M. K. Hughes, P. M. Kelly, J. R. Pilcher, and V. C. LaMarche, Jr., eds. The structure of Nineteenth Century Cities . James H. Johnson and Colin G. Pooley, eds. The American Planner: Biographies and Recollections . Donald A. Krueckeberg, ed. Urban Land Policy For the 1980s, the Message for State and Local Government . George Lefcoe, ed. Regional Planning: Evolution, Crisis and Prospects . Gill C. Lim, ed. Relevance and Ethics In Geography . Bruce Mitchell and Dianne Draper. China: The Geography of Development and Modernization . Clifton W. Pannell and Laurence J. C. MA. The Urban Retailing System . Robert B. Potter. Hants. Nonconventional Energy Resources . Philip R. Pryde. Caribbean Migrants: Environment and Human Survival on St. Kitts and Nevis . Bonham C. Richardson. Population and Resources . Harry Robinson. East Los Angeles: History of A Barrio . Ricardo Romo. Integrated Impact Assessment . Frederick A. Rossini and Alan L. Porter, eds. Environmental Aesthetics: Essays in Interpretation . Barry Sadler and Allen Carlson, eds. Earthwatch . Charles Sheffield. Field Techniques and Research Methods in Geography . Robert H. Stoddard. Haiti: Land of Poverty . Robert J. Tata. Weathering and Erosion: Sources and Methods in Geography . Stephen T. Trudgill. Once Beneath the Forest. Prehistoric Terracing in the Río Bec Region of the Maya Lowlands . B. L. Turner, II. The Historical Geography of Scotland since 1707 . David Turnock.  相似文献   
169.
Carbon emissions caused by human activities are closely related to the process of urbanization, and urban land utilization, function vitality and traffic systems are three important factors that may influence the emission levels. For clarifying the space structure of a low-carbon eco-city, and combining the concept of “Combining Assessment with Construction” to track and contrast the construction of the low-carbon eco-city, this research selects quantifiable low-carbon eco-city spatial characteristics as indicators, and evaluates and analyzes the potential carbon emissions. Taking the Jinan Western New District as an example, diversity of construction land, travel carbon emission potential, and density and accessibility of adjacent road networks in the overall urban planning were measured. After the completion of the new urban area, the evaluation mainly reflected certain factors, such as the mixed degree of urban functions, the density of urban functions, the walking distance to bus stops and the density and number of bus stops. Dividing the levels and adding equal weights after index normalization, the carbon emission potential is evaluated at the two levels of the overall and fragmented areas. The results show that: (1) The low-carbon emission potential areas in the planning scheme basically reached the planned goals. (2) There is inconsistency between districts and indicators in the planning scheme. The diversity of construction land and the accessibility of the adjacent road network are relatively small; however, there is a large difference between the travel carbon emission potential and the road network accessibility. (3) Carbon emission potential after completion did not reach the planned expectation, and the low-carbon emission potential plots were concentrated in the Changqing Old City Area and Central Area of Dangjia Town Area. (4) The carbon emission indicators varied greatly in different areas, and there were serious imbalances in the density of public transportation lines and the mixed degree of urban functions.  相似文献   
170.
Vulnerability research is the core issue and one of the research hotspots of sustainable development science. Vulnerability and its evaluation framework provide a new perspective for rural social-ecosystem studies. This paper introduced the ‘input-output’ efficiency theory and constructed the ‘SEE-PSR’ framework for the analysis of social-ecosystem vulnerability in the rural area in Qingpu District of Shanghai City. The DEA models, spatial autocorrelation model, multivariate logistic regression model, geographical detector and hierarchical cluster model were used to analyze the spatial differences of social-ecosystem vulnerability, and its geographical impact mechanisms and ecological restorations, in 184 administrative villages in this area. The results can be divided into three main points. (1) The results of the ‘input-output’ efficiency model of the EW-DEA based on entropy weight aggregation crossover was more reliable and accurate for the evaluation of rural social-ecosystem vulnerability. The vulnerability of the social-ecosystems in the administrative villages showed a trend of gradual decline from east to west, with an average value of vulnerability of 0.583, and the vulnerability of social systems had become an important factor in constraining the decrease of the vulnerability of the social-ecosystems in the region. (2) The distances from the center of Shanghai City, from Dianshan Lake, from the center of Qingpu District and from the water area were the four dominant geographical factors affecting the vulnerability of the social-ecosystem in this region. The geographical impacts exhibited the spatial differentiations of systemic structure, the substitution of typological attributes and the transformation level. (3) The geographical factors coupling the impact types of the social-ecosystem vulnerability were divided spatially into 10 types. The geographic multi-factor coupling impact types were dominant, which presented multi-cyclic spatial patterns and were dominated by the central multi-factor which was surrounded by the single factor types on both sides. According to the different types, some feasible ways of ecological restoration were proposed, which drew on the experiences of integrated territory consolidation to remediate the vulnerability of rural social-ecological systems. The results of this study can provide scientific reference for rural spatial reconstruction, regional ecological restoration and sustainable development for the regions characterized by conflict in the ‘strict protection of the ecological environment and vigorous development of the economy’.  相似文献   
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