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1.
基于改进贝叶斯模型的四川省主要河流水质评价   总被引:1,自引:1,他引:0  
提出了改进的地面水水质评价贝叶斯模型(Bayes),将抽样误差正态分布原理用于估计Bayes公式中的似然概率.改进的贝叶斯模型应用于四川省8条主要河流12个代表站点的多年水质监测数据的评价,并分别对1971-1988年和1990-2004年的四川省主要河流12个代表监测站点的水质评价结果进行分析.评价结果表明改进的贝叶斯模型较为全面、客观地反映了四川省主要河流的多年水质状况特征和污染状况,为河流水质评价提供了一条新途径.  相似文献   

2.
【目的】探讨一种科学、客观的水质大数据的综合评价方法,为刁江流域重金属污染治理提供客观数据。【方法】基于α-截集的三角模糊数-贝叶斯模型,选取刁江的5个监测断面的主要污染因子(Pb、Cd、As)进行分析,全面评价刁江水质状况。应用α-截集处理监测结果的三角模糊数,并运用到贝叶斯模型中,计算刁江水质综合得分,最终确定水质类別。最后将本研究模型的评价结果与传统贝叶斯模型、三角模糊数模型及年均值模型的评价结果进行比较。【结果】本研究模型评价结果显示,2015年刁江A、D断面水质达到Ⅱ类水标准,E断面水质达Ⅰ类水标准,B、C断面水质介于Ⅱ、Ⅲ类水之间,对各级的隶属度分別为(0.7517/Ⅱ,0.2483/Ⅲ)、(0.7449/Ⅱ,0.2551/Ⅲ),水质总体良好,环境风险可控。传统贝叶斯模型与本研究模型的评价结果接近,三角模糊数模型次之,均值模型在水质不稳定时相差较大。【结论】本研究模型兼具三角模糊数模型的不确定性、传统贝叶斯模型的决策性及均值模型在评价稳定水质中的优越性,既能准确评价水质又能将水质的不确定性表达得更为全面、切合实际。  相似文献   

3.
模糊综合评价模型在水质整体质量 评价中的应用   总被引:3,自引:0,他引:3  
构建了水质模糊综合评价模型,并以雅安市青衣江龟都府水质监测断面为例,对比分析了水质的单因子评价法和模糊综合评价方法的特点.结果表明:雅安市青衣江龟都府水质的单因子评价结果为Ⅲ类,模糊综合评价结果对Ⅰ、Ⅱ、Ⅲ类水质标准相应的隶属度分别为0.771 6,0.178 1,0.050 3,反映尽管断面水质在单因子评价中为Ⅲ类,但大部分监测指标能达到Ⅰ、Ⅱ类标准,模糊综合评价比单因子评价法更能全面地反映水质状况.  相似文献   

4.
以大连市8个地点的地下水为研究对象,采用主成分分析和模糊综合评价法相结合评估了地下水水质状况,并分析了影响地下水水质的主要因素.结果表明,使用主成分分析,可将5个水质指标综合为1个主成分进行解释,解释率为69.478%,水质综合控制指标为总硬度和溶解性总固体.模糊综合评价法预测8个地点地下水中,1个为Ⅰ类水、1个为Ⅱ类水、5个为Ⅲ类水、1个为Ⅴ类水.主成分分析和模糊综合评价法预测地下水水质排名不完全一致,但总体趋势相同,说明两种模型都比较适合预测大连市地下水水质,而且两种模型结合使用后综合预测结果要比单一预测模型更加可靠.  相似文献   

5.
通过对河西不同区域戈壁水文资料的调查和对采集水样水质的检测分析表明:河西走廊戈壁水质总体良好.从戈壁不同的分布区域水质分级来看:党河流域中下游戈壁、黑河流域中下游戈壁水质以Ⅰ类较好的水为主,未检测出Ⅲ、Ⅳ类水.疏勒河流域中下游、北山黑戈壁区域水质相对下降,均有Ⅲ类水检出.石羊河流域下游戈壁水质以Ⅱ类中等水为主,Ⅰ类较好的水比例降低,但是总体上水质良好.  相似文献   

6.
采用单因子评价法和内梅罗指数法对海宁市第二水厂水源水质进行了综合评价.单因子评价结果显示,2017年3个监测断面中高锰酸盐、溶解氧、氨氮和五日生化需氧量指数基本符合Ⅲ类水标准,总磷轻度污染.内梅罗指数法评价结果表明,2013—2017年,3个断面平均PIp值由1.841降低为1.134,泰山桥水厂由Ⅳ类转为Ⅲ类水质,杭申公路桥和丰士水泥厂桥虽暂未达到Ⅲ类水质的标准,但污染呈下降趋势,水质显著提高.  相似文献   

7.
灰色聚类法在湛江港冬季水质评价中的应用   总被引:1,自引:0,他引:1  
2006年12月底,将湛江港划分为码头和七个断面,每个断面分为三个监测点进行调查,应用灰色聚类法对其水质测量结果进行综合评价,结果表明:从空间分布上看,各监测点水质状况好坏差别较大,断面Ⅰ、Ⅱ、Ⅲ、、Ⅶ为一类水质,断面Ⅳ、Ⅴ、Ⅵ、码头为三类水质,污染严重.  相似文献   

8.
为科学、准确、迅速的评估巢湖流域饮用水中水源水的水质状况,选取了传统的模糊评价法和改进的模糊评价对庐江县湖库水系的六家自来水厂水源水的七项指标进行了水质评价。研究结果表明,采用传统模糊评价法得出其中五个水厂的水源水水质都属于Ⅰ类水,七桥自来水厂的评价结果下为Ⅲ类水。在改进的模糊评价法下六家自来水厂的评价结果均为Ⅰ类水,所有的六个水厂的水源水都符合饮用水水质标准。改进的模糊评价法采用了聚类权法,综合考虑了每个因子在每一个水质等级上对应的权重,使水质评价结果变得更加合理,该法更适合应用于巢湖流域农村饮用水水环境质量评估。  相似文献   

9.
枣庄市以岩溶地下水为主要水源,多年超采导致了地下水水质污染.枣庄市十里泉和丁庄水源地地下水中氨氮、大肠菌群及总硬度指标远高于国家地下水水质Ⅲ类水标准(GB/T 14848-93),水质综合评价结果表明,两水源地地下水水质的综合评价分值F为4.53~7.75,水质达到了较差级别,部分时段达到极差级别,其中主要污染因子是大肠菌群、总硬度,因此,岩溶地下水水质保护工作刻不容缓.  相似文献   

10.
2006年12月底,将湛江港划分为码头和七个断面,每个断面分为三个监测点进行调查,应用灰色聚类法对其水质测量结果进行综合评价。结果表明:从空间分布上看,各监测点水质状况好坏差别较大,断面Ⅰ、Ⅱ、Ⅲ,、Ⅶ为一类水质,断面Ⅳ、Ⅴ、Ⅵ、码头为三类水质,污染严重。  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.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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