生态质量综合评价的投影寻踪动态聚类方法

依据动态聚类思想，建立了投影寻踪动态聚类模型．并将该方法用于甘肃省生态环境质量综合评价中．与投影寻踪聚类方法相比，投影寻踪动态聚类方法不但可以作出环境质量的综合评价，而且消除了投影寻踪聚类方法中密度窗宽确定的人为因素，把寻优过程和聚类结果有机结合起来，为生态环境质量综合评价的研究开创了一条新途径．     

环境质量评价中关键因子识别的方法研究

应用投影寻踪聚类方法分析环境影响指标的数据资料 ,不但可以根据数据内在特性确定各评价指标的相对权重 ,避免权重人为给定的任意性 ,而且还可以通过逐次筛选找出影响环境质量的关键因子。本文将该方法成功地应用于南京市秦淮河水环境评价中 ,筛选出了影响秦淮河水质的关键因子 ,可供秦淮河水环境监测和治理作参考。另一方面 ,该方法还可以推广应用于其它类似问题的综合分析研究中。     

“空气pH值”及测定方法

为了更进一步研究大气质量及探索酸雨形成问题，提出了一个新的概念－－“空气ｐＨ值”，并定义为大气通过曝气将其中的可溶物质溶于水后，导致水中氢离子、氢氧根离子相对含量发生变化所显示出的ｐＨ值。     

评价pH值精密度的有关问题

评价ｐＨ值精密度的有关问题刘乃芝（山东省烟台市环境监测站，烟台２６４０００）鉴于ｐＨ值不能象其它项目那样直接根据平行双样测得值求相对偏差评价其精密度，而三、四级站上报数据却时常忽略此点，故建议采用以下两种方法评价ｐＨ值精密度：①将平行双样的ｐＨ值换算...     

玻璃电极法测pH值的点滴经验

玻璃电极法测ｐＨ值的点滴经验胡治州（川东天然气净化总厂环境监测站，四川长寿６３１２３６）①先用ｐＨ试纸粗测ｐＨ值大致范围，然后确定校正点。②若采用一点校正法，应选用与待测溶液ｐＨ值最接近的校正溶液进行校正并检验是否准确，选用另一校正溶液作为待测溶液进...     

测定水中总氰化物时磷酸盐缓冲溶液pH值的探讨

用异烟酸－吡唑啉酮光度法测定水中总氰化物时,对所用磷酸盐缓冲溶液ｐＨ值的使用范围进行了探讨,通过多次实验,配制了３种不同ｐＨ值的缓冲液,结果表明,ｐＨ值在６．０￣７．２之间,标准曲线的相关性和方法的灵敏度无显著差异。     

基于曲线投影动态聚类模型的大气质量监测布点研究

聚类数和聚类方法是聚类分析研究的核心,具有重要的实用价值。针对各单项大气质量监测指标的不相容问题,在投影寻踪动态聚类模型的基础上,通过引入S型曲线作为投影方式,提出了基于曲线投影动态聚类的大气质量监测布点研究新方法。从理论上讲,作为一种完全由数据驱动的方法,该模型充分体现了投影寻踪聚类的设计思想,能把最佳聚类数和对应的聚类结果的分析有机地融合在一起,具有物理意义清晰,可操作性强等特点。实例应用结果表明,通过把待研究地区大气监测点多维指标综合成一维投影指标,并利用免疫进化算法优化目标函数,模型能提供明确、客观及稳健的监测布点最佳方案,实现大气质量监测经济性和代表性的平衡。上述研究可为其它非线性、非正态高维数据分类问题开辟一条新途径。     

基于PSO-PPE模型的黑龙江省水资源生态安全探析

针对黑龙江省水资源生态环境现状,构建以水资源、社会经济、生态环境为子系统的水资源生态安全评价指标体系。运用粒子群算法(PSO)优化投影寻踪评价模型(PPE),对黑龙江省水资源生态安全进行研究。结果表明,该地区2003—2016年水资源生态安全整体呈现上升趋势。水资源污染指数和工业万元产值耗水量等指标状态的极大改善,使得2009、2013年水资源生态安全程度分别较前一年增加67.16%和98.76%。2003—2016年水资源、生态环境系统发展波动较大,前者略有降低,后者上升,社会经济系统(权重为0.426 5)发展最为迅速且对水资源生态安全影响最显著。对水资源生态安全影响最显著的指标有人均湿地面积、农业万元产值耗水量、水资源污染指数、工业用水比例、工业万元产值耗水量。该评价结果可为当地政府及环保部门制定政策提供理论参考。     

用灰色系统理论对乌鲁木齐市大气降水pH值进行预测分析

运用灰色系统理论建立灰色模型ＧＭ，对该模型进行了检验和残差修正。并用其模型分析和预测乌鲁木齐市１９９４＝１９９８年大气降水ｐＨ值。     

pH值对土壤中Pb的缓冲影响

目前Ｐｂ的环境污染随人类活动以及工业发展日趋严重,几乎在地球的每个角落都能发现其踪迹,土壤对重金属的缓冲性是土壤所具有的一个很重要的性能,是土壤中各种相互作用的综合表现。土壤缓冲性是土壤物质与外源污染物发生反应的结果,它受很多因素的影响,其中ｐＨ值是...     

Simultaneous spectrophotometric determination of trace amount of polycyclic aromatic hydrocarbons in water samples after magnetic solid-phase extraction by using projection pursuit regression

Magnetic solid-phase extraction based on coated nano-magnets Fe₃O₄ was applied for the preconcentration of four polycyclic aromatic hydrocarbons (PAHs; anthracene, phenanthrene, fluorine, and pyrene) in environmental water samples prior to simultaneous spectrophotometric determination using multivariate calibration method. Magnetic nanoparticles, carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field so, no filtration or centrifugation was necessary. After elution of the adsorbed PAHs, the concentration of PAHs was determined spectrophotometrically with the aid of a new and efficient multivariate spectral analysis base on principal component analysis-projection pursuit regression, without separation of analytes. The obtained results revealed that using projection pursuit regression as a flexible modeling approach improves the predictive quality of the developed models compared with partial least squares and least squares support vector machine methods. The method was used to determine four PAHs in environmental water samples.     

地表水体中藻类的生长对pH值及溶解氧含量的影响

论述了水质富营养化后藻类生长对pH值及DO的影响,并对pH的变化给出了定量公式,对水中藻类的生长给出了pH限值。     

Effects of pH on the water solubility and 1-octanol-water partition coefficient of 2,4,6-tribromophenol

2,4,6-Tribromophenol (TBP) is expected to exist in both ionic and non-ionic forms in the environment due to ionisation of the phenolic group at near neutral pH. In this study, the water solubility (Sw) and 1-octanol-water partition coefficient (Kow) of aqueous solutions of TBP at various pH values were measured using the shake flask method. The ionisation resulted in increasing Sw and decreasing Kow by two to three orders of magnitude. From the experimental results, the environmental partitioning characteristics of TBP and the effect of pH on partitioning were discussed through a comparison with the properties of tetrabromobisphenol A (TBBP-A), which has two phenolic groups. Furthermore, the pH dependence of Sw and Kow was represented using a Henderson-Hasselbalch type model and the validity of the model was evaluated. The model was found to be highly useful for predicting the pH dependence within the range of pH 3 to 9.     

Study of the effect of pH, salinity and DOC on fluorescence of synthetic mixtures of freshwater and marine salts

In order to provide support for the discussion of the fate of organic matter in estuaries, a laboratory simulation was performed by changing freshwater ionic strength, pH and organic matter content. The change in spectroscopic characteristics caused by variations in salinity, pH and organic matter concentration in the filtered samples was observed by UV-Vis and fluorescence spectroscopy. The increase in emission fluorescence intensity of dissolved organic matter (DOM) due to increasing salinity (in the range 0 to 5 g l-1) is affected by the pH of the samples. The emission fluorescence intensity at the three maxima observed in the fluorescence spectra, is linearly correlated with dissolved organic carbon (DOC) concentration at several salinity values in the same sample. The increase in organic matter concentration caused a shift in the emission peak wavelength at 410 nm for several salinity values. We concluded that it is necessary to take into account the influence of salinity and pH on emission fluorescence of dissolved organic matter if it is to be used as a tracer in estuarine or near shore areas.     

现行pH值平均值计算方法的不足与改进

分析了pH均值的计算原理、现行计算方法的可行性与局限性,提出一组新的计算方程式,比较两种方法计算结果的差别,并给出新方程式求解的计算程序。     

九龙江北溪pH值异常变化与生化因子相关性的研究

监测结果表明,九龙江北溪部分断面CODMn浓度介于中富营养～富营养之间,总氮、总磷和叶绿素a浓度均达到极富营养水平。经统计分析,pH值与甲藻显著相关(r=0.327,P=0.025),与溶解氧(r=0.762,P=0.000)、高锰酸盐指数(r=0.456,P=0.001)、总氮(r=0.482,P=0.001)、总磷(r=0.507,P=0.000)和叶绿素a(r=0.649,P=0.000)等非常显著相关。研究表明,虽然各项化学因子与pH值密切相关,但不是pH值变化的直接原因,而是由于水体富营养程度严重且已形成了藻类生境,甲藻的异常增殖才导致pH值异常升高。     

湖泊中水下植物光合作用对溶解氧和pH值的影响

文章研究了湖泊中水下植物光合作用对湖水ＤＯ和ｐＨ的影响，提出了预测ＤＯ和ｐＨ变化的计算方法     

The Influence of pH on Mobility of Heavy Metals from Municipal Solid Waste Incinerator Fly Ash

Incineration has become one of the principal methods for municipal solid waste disposal particularly in all large cities throughout the world. Currently, the municipal solid waste incinerator fly ashes (MSWIF) are disposed of by landfill. The metal speciation of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in MSWIF after been extracted with water at different pH values were examined using a sequential extraction procedure. The extraction sequence was as follows: (1) Exchangeable (NaOAc, pH 8.2), (2) Bound to Carbonates (NaOAc, pH 5.0), (3) Bound to metal oxides (HONH3Cl), (4) Bound to organic matters (HNO3, H2O2), and (5) Residual (HNO3, HCl, H2O2, HF, 1:3:1:3). The heavy metal contents in the extraction solutions were determined by inductively coupled plasma atomic emission spectrometry. The heavy metal concentrations in the different fractions obtained by sequential extraction show distinct distribution trends. The extractable fraction ranges from 25.5 to 88% of the total element content. With the pH of the extractant fall below the neutral and acidic ranges, the concentrations of heavy metals rise substantially due to the released of metals bound to carbonate fraction.