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61.
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The study of trace metal speciation has benefited from a great deal of interest leading to the development and the diversification of sequential extraction schemes (SES), which triggered the need for harmonization by the standard, measurements and testing programme (SM & T). However, some uncertainties still persist in the application of the harmonized 3-step protocol, because of the difficulty in conceptualizing a technique that can be applied to environmental samples irrespective of their nature. The alternative method proposed in this study is based on the solubility of the sample components progressively dissolved during the course of an acidimetric titration by 1 mol L−1 HCl. The major HCl-reactive mineralogical components are identified using mass balance calculation of H+ consumed by their dissolution together with the amount of major elements released into solution. The speciation of minor and trace elements is investigated by comparing their titrations to those of the major elements. This approach is much simpler than SES because it uses simple non-selective H+ at room temperature instead of a complex experimental design of so-called specific reagents. The different mineral components of the solid are no longer operationally defined and the problem of selectivity is irrelevant to the titration approach. The method was applied to several sediment samples from the Scheldt estuary and the particulate phase was further examined by Scanning Electron Microprobe and X-ray Diffraction techniques. The nearly complete consumption of H+ in the suspension is balanced by the total dissolution of carbonates and Fe-oxyhydroxides. In contrast to the speciation inferred from the Tessier SES, the acidimetric titration has demonstrated that the carbonate phase does not significantly contain trace metals with the exceptions of 40% of the Mn and 30% of the Co. In contrast, the Fe-oxyhydroxides seem to play a major role and account for 70% of Pb and 20% of Cr, in addition to 60% of P and additional amounts of 20% Co and 40% Mn. 70% of the Cu also occur in the oxyhydroxide phase, more likely coprecipitated with gibbsite. 90% of the Cd and 85% of Zn can be attributed to the Acid Volatile Sulfide (AVS) phase as evidenced from S titration. The acidimetric titration method not only provides information on the speciation of trace metals but also allows the quantification of their reactivity and mobility, if one considers that the titration roughly mimics pH changes that may occur as a result of chemical disequilibrium in the environment. The results demonstrate the potential of the acidimetric titration as an alternative to SES protocols in geochemical and environmental regulation studies. This method is applicable to a wide variety of environmental materials with little or minor adjustments. 相似文献
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山东及周边地块间近期运动状态分析 总被引:2,自引:0,他引:2
为研究山东所在块体及周边地块间的地壳相对运动状态,利用2001年以来中国地壳运动观测网络以及2007年以来山东GPS观测网的观测结果,使用K-L最佳直线拟合和滑动傅里叶法得到基线变化年周期,以此对处于不同地块的GPS基准站间基线变化趋势进行分析,得出近期山东内部及周边地块间的地壳运动特征。并利用GPS资料分析了2011年3月11日日本9.0级强震对山东地区的影响。 相似文献
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Silva Vinicius Oliveira de Mello Carlos Rogério Chou Sin Chan 《Theoretical and Applied Climatology》2022,148(3-4):1289-1302
Theoretical and Applied Climatology - South of Minas Gerais state, in Southeast Brazil, is known for the coffee crop production (more than 30% of country’s production) and hydroelectricity... 相似文献
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Energy serves as an alternative index to response quantities like force or displacement to include the duration‐related seismic damage effect. A procedure to evaluate the absorbed energy in a multistorey frame from energy spectra was developed. For low‐ to medium‐rise frames, it required a static pushover analysis of the structure to determine the modal yield force and ductility factor of an equivalent single‐degree‐of‐freedom system for the first two modes. The energy spectra were then used to determine the energy contribution of each mode. A procedure was also developed to distribute the energy along the frame height based on energy shapes. This study showed that the second‐mode response in some cases needs to be considered to reflect the energy (or damage) concentration in the upper floors. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
69.
在盐湖沉积演化过程中,钾镁盐在盐类矿物沉积的中晚期才开始结晶析出。因此,研究含盐系地层中盐类矿物的沉积地球化学特征,不仅可以从侧面获取岩盐的沉积物物质来源和成盐期古卤水蒸发浓缩程度等地球化学信息,而且可以直接揭示古盐湖期钾盐富集趋势及规律。目前,除在江陵凹陷的古近系沙市组等含盐系内发现了富钾卤水外,还在中-南部的钻孔盐矿盐岩中,发现了微量钾石盐和钾石膏,这些说明该凹陷古近纪具有成钾潜力。本文通过对SK3井蒸发岩特征研究及岩芯中K、Mg、Cl、Br离子含量与Br×103/Cl系数的垂向变化分析,揭示古盐湖浓缩演化与钾盐富集趋势,进一步揭示该层段沉积时期及所在凹陷古盐湖卤水钾的富集程度。 相似文献
70.
形变监测是海塘安全运行的重要组成部分。本文利用杭州地区2006年—2010年获取的31景EnvisatASAR影像,根据MTInSAR(Multi-Temporal In SAR)方法,综合提取PS(Persistent Scatterer)和DS(Distributed Scatterer)点,得到密集的钱塘江海塘形变的In SAR测量结果。与28个点的水准数据对比表明,两者的平均误差为0.436 mm,最大误差为5.016 mm,验证了In SAR技术毫米级的测量精度和准确性。通过这两种数据的时间序列分析发现,海塘的沉降在空间上具有连续性,其空间分布呈现为单峰下沉曲线;在时间上,则具有明显的线性变化规律,并伴随有短时间范围的小幅度波动。 相似文献