共查询到20条相似文献，搜索用时 93 毫秒
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山东省东营市作为国家战略建设开发区,随着城镇化和工农业的快速发展,并由于其自身存在的地质环境问题,致使水环境压力日益增大。日益严峻的水环境形势已严重限制了东营地区的发展,因此东营市水环境承载力的研究对于维系地区水资源、水环境和社会经济和谐可持续发展有重要的指导意义。结合水环境承载力的特点,建立了评价指标体系,应用基于离差平方和最大的组合赋权方法对各指标进行了权重计算,并采用对数承载率模型,对东营市水环境承载力进行了计算和评价。得出2002-2014年东营市水环境承载力整体水平虽然较差,但在向好的方向发展;得出影响东营市水环境承载力的主要因素有水资源量、水环境容量和第三产业占比;最后针对3个方面给出了提高东营市水环境承载力的建议和措施。 相似文献
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《地球科学进展》2017,(1)
沿海地区是当前我国经济社会发展程度最高、生态环境压力最大的地区,而沿海规划建设项目决定了海岸带资源环境开发利用的规模、强度及空间格局。生态承载力评价是项目规划可持续开发利用海岸带自然资源、保护生态环境、确保经济社会健康可持续发展的必要前提。基于常规沿海项目规划对海岸带产生的资源环境压力类型,从提升生态承载力评价应用价值角度界定了海岸带生态承载力的概念和内涵,系统总结、回顾了国内外生境适宜性评价、陆域建设用地开发适宜性评价、围填海生态适宜性评价与海域水环境容量评价研究发展进程,指出我国海岸带生态承载力评价亟需广泛参考借鉴国外研究成果,构建系统完整的生态承载力评价方法体系,并在生态承载力量化评价及空间可视化研究领域展开深入探索,为促进我国沿海地区经济社会生态文明发展建设进程提供有力支撑。 相似文献
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在对玛纳斯河水环境承载力评价指标体系详细分析的基础上,建立玛纳斯河水环境承载力综合评价指标体系及模型。根据建立水环境承载力评价指标体系的指导思想、特征及内涵建立生态、人口及经济三个方面的水环境承载力子系统,运用层次分析法（AHP）计算出各指标的权重值,得出各指标的重要性排序;应用承载度的模型,得出玛纳斯河水环境承载度;结合模糊综合评判分析法计算出玛纳斯河水环境承载力;分析玛纳斯河水环境承载力的变化规律,找出影响玛纳斯河水环境承载力的因素。构建玛纳斯河流域水环境承载力计算系统的数学模型。 相似文献
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探讨了基于水基系统概念的区域水资源水环境保护治理思路,定义了具有持续性、随律性和变化性的定尺度水基系统演进的符点目标,从水资源承载力和水环境承载力的角度建立了区域水资源水环境取排水控制关系,用BP人工神经网络智能方法提出了对水量水质耦合过程以及水价调节作用进行学习、训练的架构,从而为推求区域水资源水环境保护治理的符点目标进行了步骤与方法的探索. 相似文献
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以水功能区为基本单元,采用一维水质数学模型分析计算渭河流域水环境承载能力,分析评价水环境质量状况;以纳污能力为约束条件,分析归纳出各水功能区和支流区域的排污控制量和削减量;并分析流域水环境承载力和实际承载状况的空间分布。就流域的水环境治理措施、产业结构的调整和社会经济的发展布局进行了讨论。 相似文献
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用基于信息熵理论的模糊物元分析法进行区域水资源承载力综合评价,并在此基础上进行合理的改进和运用,结合欧氏贴近度实现不同评价分区的量化比较,得到各分区水资源承载力水平及其优劣次序。实例表明,相对于常规的灰色物元分析法、模糊综合评价法等,该方法更能反映问题实质,评价结果合理,有助于塔里木河流域的水资源利用与经济社会发展的协调。 相似文献
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A DEM-based evaluation of potential flood risk to enhance decision support system for safe evacuation 总被引：2，自引：1，他引：1
A practical, DEM-based practical method is proposed to enhance flood risk management in fluvial areas by quantifying relative
risk as a function of vulnerability to inland and evacuation difficulty. Both measures are based mainly on the topography
of the region, so the method does not require detailed data on the physical characteristics of the land. First, we use the
deterministic 8-node method on a digital elevation map (DEM) to trace storm waterways. Second, we repeat the process on a
reversed DEM to trace evacuation routes that avoid the waterways and zones dangerously close to the rivers. Finally, on the
basis of such two flow lines of evacuee and storm water, we proposed the protocol to evaluate the flood risk at every point
on the map taking into account both the minimum time required for floodwater to arrive and duration of an evacuation from
that location. The time that must be allocated for safe evacuation is defined as the potential flood risk of evacuation (PFRE).
The method is demonstrated on a fluvial area of the Kaki River in Nagaoka city, Japan. In addition, we illustrated the application
of the PFRE map to divide the region into areas of greater or lesser evacuation urgency. 相似文献
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A study on quantifying offshore pipeline resistance during vertical penetration and axial walking is presented, based on coupled pore pressure and displacement finite element analysis with the Modified Cam Clay model. Following the validation of the numerical method against published centrifuge test results and limit analysis solutions, we present the findings of a detailed parametric study on the response of partially-embedded pipelines under vertical and axial movements, employing 2-D plain strain and full 3-D soil–pipeline models. Emphasis is put on practical findings, and on proposing simplified expressions for the estimation of the contact enhancement factor and of the equivalent friction factor, that can be used at least for preliminary design purposes. 相似文献
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R. Braucher D. L. Bourls E. T. Brown F. Colin J. -P. Muller J. -J. Braun M. Delaune A. Edou Minko C. Lescouet G. M. Raisbeck F. Yiou 《Chemical Geology》2000,170(1-4):95-111
Depth profiles of in situ-produced cosmogenic nuclides, including 10Be (T1/2=1.5×106 years) and 26Al (T1/20.73×106 years), in the upper few meters of the Earth's crust may be used to study surficial processes, quantifying denudation and burial rates and elucidating mechanisms involved in landform evolution and soil formations. In this paper, we discuss the fundamentals of the method and apply it to two lateritic sequences located in African tropical forests. 相似文献
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The estimation of 3D grain size distributions (GSDs) in mylonites is key to understanding the rheological properties of crystalline aggregates and to constraining dynamic recrystallization models. This paper investigates whether a common stereological method, the Saltykov method, is appropriate for the study of GSDs in mylonites. In addition, we present a new stereological method, named the two-step method, which estimates a lognormal probability density function describing the 3D GSD. Both methods are tested for reproducibility and accuracy using natural and synthetic data sets. The main conclusion is that both methods are accurate and simple enough to be systematically used in recrystallized aggregates with near-equant grains. The Saltykov method is particularly suitable for estimating the volume percentage of particular grain-size fractions with an absolute uncertainty of ±5 in the estimates. The two-step method is suitable for quantifying the shape of the actual 3D GSD in recrystallized rocks using a single value, the multiplicative standard deviation (MSD) parameter, and providing a precision in the estimate typically better than 5%. The novel method provides a MSD value in recrystallized quartz that differs from previous estimates based on apparent 2D GSDs, highlighting the inconvenience of using apparent GSDs for such tasks. 相似文献
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Fei Guo Xibin Ji Bowen Jin Liwen Zhao Dandan Jiao Wenyu Zhao Jinglin Zhang 《地球科学进展》2020,35(5):523-533
Canopy conductance (gc) is a key regulating factor of carbon, water and heat exchange between vegetation and atmosphere. Reliable and reasonable gc estimation is of great significance for quantifying evapotranspiration (ET) mass and energy exchange at terrestrial surface. Based on the Jarvis model, a canopy conductance model of agroecosystem in an irrigated oasis, located in arid regions of Northwestern China, was formulated by using the time-piecewise functions of the response of leaf stomatal conductance (gs) to environmental factors and Leaf Area Index (LAI). The developed gc model was tested with the calculated results derived from the inversion of the Penman-Monteith (PM) equation, in combination with observations of environmental variables and ET measured by the Eddy Covariance (EC) method, suggesting that the developed gc model can provide reasonable prediction. In order to further assess the performance of the developed gc model, we consequently calculated ET under the conditions that LAI was larger than three, indicating that the estimation was in good agreement with the observations from EC method. It should be noted that the scaling leaf stomatal conductance to canopy conductance needs to take into account shelter factor (fs), and the corresponding function relation with LAI is obtained by fitting. These results from our present study will provide a useful approach to quantifying the gc of agroecosystems under the well-watered conditions in arid climatic areas, and then can improve the performance of ET estimation, which have important implications for well understanding the controlling mechanisms of plant on energy exchange and ET, and even for local water resources management. 相似文献
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Qualitative and quantitative knowledge about the spatial association between mineral occurrences and geological features are important in mineral potential mapping. Two existing methods for quantifying spatial association between mineral occurrences and curvilinear geological features are applied to the Baguio district of the Philippines. An experimental method is described and applied to the study area as well. The results of the three methods are highly similar, which demonstrates the effectiveness of the experimental method presented here for quantifying spatial association between mineral occurrences and curvilinear geological features. It is shown that gold occurrence in the Baguio district are strongly spatially associated with northeasterly trending faults/fractures rather than with northwesterly trending faults/fractures. It is also shown that the spatial association between the gold occurrence and older batholithic intrusives is stronger than the spatial association between gold occurrence and younger porphyry intrusives. These spatial geoinformation characteristics can be used as evidential data layers in GIS-based mineral potential mapping. 相似文献
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针 对 多 煤 层矿 井 中 常 规地 质 方 法 对煤 层 判 分 的困 难 ,提 出 了 单 因 素方 差 分 析 的地 质 数 学 方法 。该 方 法对 煤层物 理 化 学 参数 进 行 量 化考 核 ,从而 将 煤 层 区分 出 来 ,既 考 虑 了 抽 样 观 测 中 的 随 机 误 差 ,又 考 虑 了 归 属 不 同 煤 层 的系统 误 差 ,为 煤 层 判 分提 供 了 一 种新 方 法 、新 思 路 。 相似文献