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421.
磁化除垢器在循环水系统的应用 总被引:5,自引:0,他引:5
张玉春 《石油化工环境保护》1997,(2):61-62
介绍了利用磁化除垢、防垢法研制出的磁化除垢器的基本原理。此产品在工业、民用以及循环水,换热器、暖气、空调等系统上应用,取得了显著的效果。 相似文献
422.
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424.
从生物群落结构和功能的角度,阐述了生物监测和评价研究的现状;目前利用水生生物进行水质评价和监测的一些主要研究方法及发展趋势。 相似文献
425.
生态产品生命周期设计概念框架 总被引:2,自引:0,他引:2
生态产品是从原材料采掘到产品制造、运销、使用和最终报废处理整个生命周期总环境影响最小的产品,而生命周期设计是实现产品环境影响最小化和污染预防的最好方式之一。生态产品的开发,应从设计开始,生态产品生命周期设计的概念是一种基于产品系统的设计方法;其设计步骤有确定系统边界、环境现状评价、设计要求分析、各要求优先排序与协调,设计对策、设计方案评价等几个方面,随着ISO14000体系的全面建立,产品生命周期 相似文献
426.
遗传BP算法在大气环境综合评价中应用 总被引:5,自引:0,他引:5
着重介绍的遗传算法求解网络结构优化,有效解决BP算法局部收敛的遗传BP算法的原理和构建遗传BP算法的步骤,并用于焦作市大气环境质量综合评价,结果表明,该方法有简便,准确,适用性强等优点。 相似文献
427.
采用模糊聚类分析方法.对哈密市多年来城市环境噪声监测数据,进行了质量评价。结果表明,该市受到噪声中污染的Ⅳ级水平,提出了相应建议。 相似文献
428.
Vaughan H Whitelaw G Craig B Stewart C 《Environmental monitoring and assessment》2003,88(1-3):399-408
The paper describes the Ecological Monitoring and Assessment Network's (EMAN) operational and program response to certain challenges of environmental monitoring in Canada, in particular, efforts to improve the ability of the network to deliver relevant information to decision makers. In addition to its familiar roles, environmental monitoring should deliver feedback to society on environmental changes associated with development patterns, trends, processes and interventions. In order for such feedback to be effective, it must be relevant, timely, useful and accessible: all characteristics that are defined by the user, not the provider. Demand driven environmental monitoring is explored through EMAN's experiences with Canada's Biosphere Reserves, the NatureWatch Program and the Canadian Community Monitoring Network. 相似文献
429.
This article, a theoretical perspective based on a literature study, is a critical evaluation of SIA as part of the EIA process in South Africa against the background of international guidelines and best practices. It includes sections on the historical background of the development of SIA in South Africa, the legal status and requirements of SIA in the country, and a critical evaluation of SIA regulation in South Africa. The conclusion reached in the article is that the persistent problems of SIA practice, experienced in other parts of the world, are also evident in South Africa. Apart from institutional, financial and professional constraints, there are also serious problems associated with approach and methods. This conclusion confirms the findings of empirical studies that SIA in South Africa is neglected, that the practice of SIA in South Africa is not yet on a sound footing, and that it does not receive the professional attention it deserves in a country beset by enormous social challenges. To conclude the article recommendations are made to improve the level of SIA practice in South Africa, and the possible significance of this national case study for international practice is indicated. 相似文献
430.
Robert E. Zuellig Daren M. Carlisle 《Journal of the American Water Resources Association》2019,55(1):102-115
Detecting trends in biological attributes is central to many stream monitoring programs; however, understanding how natural variability in environmental factors affects trend results is not well understood. We evaluated the influence of antecedent streamflow and sample timing (covariates) on trend estimates for fish, invertebrate, and diatom taxa richness and biological condition from 2002 to 2012 at 51 sites distributed across the conterminous United States. A combination of linear regression and Kendall‐tau test for trends were used to evaluate covariate influence on trend estimates. Adjusting for covariates changed the magnitude of trend estimates in two‐thirds of cases on average by 21%, most often reducing the estimated magnitude of the trend. Additionally, covariates influenced the interpretation of over one‐third of trend estimates by either strengthening or weakening trends after adjustment. Our findings clearly indicate that antecedent streamflow and sample timing influences trend estimates and subsequent interpretation. Accounting for covariates during trend analysis will enhance stream monitoring programs by providing a better understanding and interpretation of estimated changes in biological endpoints at monitored sites. Failure to account for antecedent streamflow and sample timing may lead to mischaracterization of a trend and/or misunderstanding of potential causes. 相似文献