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201.
MFAM模型在河流水质污染模拟及预测中的应用 总被引:2,自引:0,他引:2
文中以时间序列分析为基础,介绍了均值生成函数这一崭新概念,并且经成份因子提取分析推导建立了模拟序列的数字模型(简记为MFAM),经对黄河下游花园口断面的1988-1989年实测水质污染指标溶解氧(DO),氨氧,化学耗氧量(COD),五日生化需氧量(BOD5)等序列模拟,结果表明MFAM模型能较好地模拟河流水质污染指标的变化趋势,拟合平均误差只有5.2-6.4%,MFAM模型应用于预测1990-1991年水质污染指标变化,结果表明预测精度达85%以上,文中最后得出结论:MFAM模型应用于河流污染模拟和预测,是完全可行且十分方便。 相似文献
202.
In this study, we analyzed the sustainability and determinant factors of waste reduction through variable charging schemes.
We drew three main conclusions from the study. (1) Waste reduction was achieved by variable charging and was sustained over
an average of at least 10 years. The results regarding the sustainability of the price effect were inconclusive. (2) The main
factors contributing to the combustible waste reduction achieved through variable charging were two-tier pricing and the price
of waste bags. The effect of two-tier pricing programs was positive. (3) Waste paper recycling and variable charging reinforce
each other to promote waste reduction.
Received: September 3, 2001 / Accepted: January 13, 2002 相似文献
203.
甲撑二苯基二异氰酸酯 (MDI)生产过程中涉及到了多种危险有害因素。笔者通过对国内现役MDI生产装置进行调研 ,同时结合国内外其他涉及光气生产厂家的情况 ,分析并指出了生产过程中可能出现的危险有害因素 ,从而提出了相应的对策措施 相似文献
204.
Ton H. Snelder Barry J. F. Biggs 《Journal of the American Water Resources Association》2002,38(5):1225-1239
ABSTRACT: River Environment Classification (REC) is a new system for classifying river environments that is based on climate, topography, geology, and land cover factors that control spatial patterns in river ecosystems. REC builds on existing principles for environmental regionalization and introduces three specific additions to the “ecoregion” approach. First, the REC assumes that ecological patterns are dependent on a range of factors and associated landscape scale processes, some of which may show significant variation within an ecoregion. REC arranges the controlling factors in a hierarchy with each level defining the cause of ecological variation at a given characteristic scale. Second, REC assumes that ecological characteristics of rivers are responses to fluvial (i.e., hydrological and hydraulic) processes. Thus, REC uses a network of channels and associated watersheds to classify specific sections of river. When mapped, REC has the form of a linear mosaic in which classes change in the downstream direction as the integrated characteristics of the watershed change, producing longitudinal spatial patterns that are typical of river ecosystems. Third, REC assigns individual river sections to a class independently and objectively according to criteria that result in a geographically independent framework in which classes may show wide geographic dispersion rather than the geographically dependent schemes that result from the ecoregion approach. REC has been developed to provide a multiscale spatial framework for river management and has been used to map the rivers of New Zealand at a 1:50,000 mapping scale. 相似文献
205.
随着工、农业的发展,洞庭湖区域的环境污染日趋严重。本文较详细地研究了洞庭湖区域的环境整治规划,在各环境要素的规划方面进行了探讨。 相似文献
206.
本文对四川盆地森林覆盖率的影响因素进行逐步回归分析,结果表明影响森林覆盖率的自然因素是综合的,它包括气候、地貌、土壤等自然条件。其中以7月降水量、地形崎岖度、山地比例、酸性紫色土比例及土地垦殖系数等作为决定四川森林覆盖率变化的最重要因素,这5个因素即可解释盆地森林覆盖率80%以上的变化。 相似文献
207.
中国山区沟谷泥石流危险度的定量判定法 总被引:22,自引:5,他引:22
本文根据专家系统调查,确定了一次泥石流冲出物最大方量和泥石流暴发频率作为判定泥石流危险度的主要危险因子。运用灰色关联度分析,优选出10项判定泥石流危险度的次要危险因子,并根据关联序确定了它们的权重。在各危险因子等级划分的基础上,得出了泥石流危险度的定量计算公式。通过实例检验,证明该判定方法具有60%以上的可靠度。 相似文献
208.
孙景民 《中国环境管理干部学院学报》1999,(3)
针对全国报刊治理整顿后多数学报由内部发行转为正式学报类期刊的新情况,本文从学报业务工作的几个方面对全面提高成人高校学报(以下简称“成高学报”)办刊质量进行了较详细的论述,旨在对成高学报的办刊工作起到一些促进作用。 相似文献
209.
Agarwal R Jayaraman G Anand S Marimuthu P 《Environmental monitoring and assessment》2006,114(1-3):489-504
The study focuses on assessing the status of respiratory morbidity in Delhi over a four years period from 2000–2003. An attempt was made to investigate the role of important pollutants (SO2, NO2, SPM and RSPM) and various meteorological factors (temperature minimum & maximum, relative humidity at 0830 and 1730 hrs. and wind speed) in being responsible for respiratory admissions on account of COPD, asthma and emphysema. The study showed that winter months had greater exposure risk as pollutants often get trapped in the lower layers of atmosphere resulting in high concentrations. Statistical analysis revealed that two pollutants have significant positive correlation with the number of COPD cases viz., SPM (r = 0.474; p < 0.01) and RSPM (r = 0.353; p < 0.05), while a meteorological factor temperature (minimum) has a significant negative correlation (r = −0.318; p < 0.05) with COPD. Stepwise multiple regression analysis was performed for COPD as dependent variable and R2 value of 0.33 was obtained indicating that SPM and RH(1730) were able to explain 33 percent variability in COPD. The partial correlation of SPM and RH(1730) on COPD was higher than any other combination and therefore they can be regarded as important contributing variables on COPD. 相似文献
210.
The micronucleus test of peripheral blood erythrocytes was used to study cytogenetic stability in bream (Abramis brama L.), perch (Perca fluviatilis L.), roach (Rutilus rutilus L.), and pike (Esox lucius L.) from a eutrophic water body not affected by anthropogenic factors. The dependence of the rate of spontaneous micronucleus formation on fish age was estimated. The effect of natural variation in abiotic environmental factors on the cytogenetic stability of species was analyzed. 相似文献