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1.
南水北调工程水质安全事关国计民生,而突发性水环境污染事故对水质安全构成了重大威胁,有必要对工程突发性水环境污染事故预防与应急处理措施进行全面研究.本文从分析南水北调东线工程水环境污染事故产生隐患着手,提出了一系列预防与应急处理措施,构建了南水北调东线工程水环境污染事故预防与应急处理机制的总体框架.随着研究的进一步深入,相关措施逐步得到完善,对保障我国南水北调工程水质安全将具有重要意义.  相似文献   

2.
 流域水环境模型是研究流域水环境问题的重要工具。梳理了流域尺度水环境污染模型及水质风险评价方面的模型,基于流域水环境的污染负荷、水质模拟对整个流域合理规划、管理管控的重要性,从水环境污染负荷模型、水质模拟模型及水环境质量评价3个层面,探讨了各类水环境模型的特征及适用性。结合农业非点源与城市非点源污染负荷模型、稳态与动态模拟水质模型、确定性与不确定性水质评价模型,剖析了流域水环境模型的研究应用进展。  相似文献   

3.
淮河流域是我国历来重要的经济文化发展重要的地区,随着人口的增加和经济的发展,淮河在水患灾害还没有彻底整治的情况下,又出现了严重的水环境污染现象,严重制约了该地区的发展。近年来,通过治理淮河水质有所好转,但是水污染依然形势依然严峻,通过对淮河水质现状的分析,提出旨在改善淮河水环境污染现状的防治对策。  相似文献   

4.
论述了三峡重庆库区水质现状,分析了水环境污染的原因,提出了三峡重庆库区水污染的保护对策。  相似文献   

5.
为了综合防治湿地水环境污染,对华北衡水湖湿地的水质数据进行了评价。应用了4种不确定性模型(模糊模型、灰色模型、物元分析、人工神经网络法),分析了衡水湖湿地年内水位、水温、溶解氧浓度和氨氮浓度的变化。利用环境流体动力学模型(EFDC)模拟,与衡水湖2003年的实测水质监测数据进行比较。结果表明:衡水湖水质基本为四类水到五类水;与其他3种方法的评价结果相比,人工神经网络法能够较为客观的评价衡水湖湿地水质;EFDC模型可以应用于衡水湖的水环境模拟预测。  相似文献   

6.
李木俊 《科技信息》2009,(30):328-330
本文研究了环境友好型水质稳定剂在天福化工循环冷却水系统中的清洗、预膜及日常应用效果。结果表明:使用环境友好型水质稳定剂后,大大地降低了水的消耗,提高水的循环利用率,减少了清洗污水的排放和日常运行中的环境污染,缓蚀、阻垢效果较好,延长了设备的使用寿命,具有很好的经济、社会和环境效益。为同类工程应用具有借鉴和指导意义。  相似文献   

7.
通过单因子评价法对双树寺水库2010年-2014年水环境状况进行分析评价,评价过程计算简单、结果对比直观。通过实际应用得出单因子评价在水质评价中的推广应用有利于优化水环境管理和推进水环境污染的治理工作。本次评价的结果是2010年为Ⅰ类水质、2011年为Ⅱ类水质、2012年为Ⅱ类水质、2013年为Ⅱ类水质、2014年为Ⅰ类水质。水库水体未收到污染,水质优良。  相似文献   

8.
根据近年来对西枝江各河段水源水质的监测结果,着重评估了该水域的水环境污染状况,从中探讨对本流域的环境保护对策,并提出建设西枝江流域生态区的设想。  相似文献   

9.
巡司河是武汉市主城武昌东南部地区主要排水河道,如今环境污染非常严重。在巡司河流域进行巡司河水污染问卷调查,了解该河污染相关情况,并选取pH值、DO、COD、BOD、NH3-N、P、总Cr等水质因子,对巡司河水质进行相关监测,得到巡司河水质超过国家五类水水质标准。最后,对改善巡司河污染现状提出一些看法。  相似文献   

10.
境内主要河流发黑发臭,近岸海域赤潮频繁发生,饮用水库水质下降,水环境污染已经成为制约深圳市社会经济可持续发展的重要因素。 深圳市水环境质量日趋下降,情况不容忽视,如何治理水污染、改善水环境成为深圳市政府重大任务之一。水环境污染严重2002年深圳市总人口为504.25万人,生活污水排放量达91885万吨,工业废水排放量达4561万吨,比1996年分别增长40.7%、67.0%和36.5%。人口的快速增长,使水污染源大幅度增加,但由于城市基础设施的滞后,导致全市80%的河段受到有机物污染,饮用水源也受到威胁。(一)饮用水源水质受到污染1996~2002年,深圳水…  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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