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为探索煤矸石填筑路基的合理碾压方式,以青兰高速邯涉段工程为依托,采取煤矸石路基填筑冲击压实与普通振动压实后冲击增强补压两种碾压方式铺筑试验路,分别采用灌砂法和沉降法对不同试验段压实度进行对比检测,同时对碾压前后的煤矸石进行取样筛分试验和压碎值试验,最后分析了不同压实方式对煤矸石路基的压实度、级配及压碎值的影响效果. 相似文献
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钨碱性萃取是一种钨湿法冶金清洁生产技术,所用的三辛烷基甲基氯化铵(N263)萃取剂存在转型率低、操作复杂等问题,不利于该技术的推广应用。采用自制的钨碱性萃取剂三长链烷基甲基碳酸盐(GW05),在无需转型的前提下,对Na2WO4溶液进行了萃取、反萃取和再生实验,并与N263的钨萃取性能进行了对比,取得了比较好的效果。较优的萃取条件为:油水比(O/A)2∶1,搅拌时间10 min,萃取温度20℃,料液p H值9~14。在相同的萃取条件下,GW05的单级萃钨率较N263萃取剂要高5%~10%。绘制了GW05和N263的萃取等温线,其萃钨饱和容量大致相同,分别为80.69和79.33 g·L-1。进行了串级错流萃取实验,对于WO3含量为114.28 g·L-1的Na2WO4溶液,N263在3级萃取的条件下可以达到99.78%的钨萃取率,GW05在2级萃取的条件下即可达到99.26%的钨萃取率。用2.5 mol·L-1的NH4HCO3溶液对GW05和N263萃取后所得的萃合相进行串级错流反萃取对比实验,GW05的萃合相表现出较好的反萃取性能。将GW05和N263反萃后所得有机相用1.0 mol·L-1的Na OH溶液进行再生,GW05和N263仍然具有较好的萃取性能。 相似文献
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长江流域大尺度空间非点源污染负荷研究 总被引:6,自引:1,他引:5
在国内外相关研究的基础上,利用输出系数模型,结合RS和GIS技术,对长江流域的非点源污染负荷进行了空间模拟和负荷估算,得出了长江流域化学需氧量、总氮、总磷和氨氮非点源污染负荷及其空间分布图。2000年,长江流域非点源污染产生量为:化学需氧量约2 347.3万t、总氮1 001.0万t、总磷231.3万t、氨氮300.6万t。就分布空间而言,洞庭湖水系、湖口以下干流、鄱阳湖水系和太湖水系对长江中下游的非点源污染贡献较大。对长江流域这样超大尺度空间的非点源污染进行空间模拟,对非点源污染研究和控制具有重要的理论和实践意义。 相似文献
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亚流域划分对分布式水文模型模拟结果的影响 总被引:13,自引:0,他引:13
本文以GIS技术为支持,选择黄河下游支流洛河卢氏水文站以上流域为研究区域,应用分布式水文模型SWAT (Soil and Water Assessment Tool)在不同的亚流域划分数量条件下进行流域产流和产沙模拟,进而分析亚流域划分对分布式水文模型模拟结果的影响,结果表明:(1)产流量随亚流域数量的增加而增大,变化幅度较小;产沙量随亚流域数量的增加而减小,变化幅度较大;(2)存在一个亚流域划分水平,当超过此水平时亚流域数量的变化对产流量和产沙量几乎没有影响。根据计算流域产沙量的MUSLE方程,分析了由于亚流域划分数量变化对流域产沙的影响,发现在研究区内其主要原因为MUSLE中径流项对亚流域划分数量变化的响应,其次是土壤可蚀性因子、植被覆盖和管理因子和地形因子参数值的统计变化。 相似文献
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Vertical distribution of rare earth elements in a wetland soil core from the Sanjiang Plain in China 总被引:2,自引:0,他引:2
The objective of this study was to investigate the vertical distribution of rare earth elements (REEs) in a natural wetland soil core to understand the influence of natural and anthropogenic activities on geochemical behavior of REEs. A natural wetland soil core of 95 cm was collected from the Sanjiang Plain in China and sliced into 5 cm slices for analyses of REEs, Fe, Al, Mn, Sc, Y, and soil organic matter (SOM). Results indicated that SOM was accumulated in the upper part of the soil core (0 to 20 cm depth), while Fe and Mn was reductively leached from the upper part of the soil core and accumulated in the low part. The content of total REEs ranged from 137.9 to 225.9 mg/kg in the soil core. Content profiles obtained for all REEs were almost identical except for Ce. The highest contents of REEs generally occurred at about 20 cm depth, but enrichment factor (EF) of REEs except Ce was usually the highest in the surface horizon. Average EF ranged from 1.1 for La to 2.1 for Gd. The pronounced shift in EF occurred at about 40 cm depth and it gradually increased from 40 cm depth to surface (except for Ce), probably suggesting anthropogenic atmospheric deposition of REEs. In comparison with chondrite, Eu was depleted in all horizons, while Ce was negatively anomalous in the top horizons and positively anomalous in the bottom horizons. This positive anomaly of Ce in the bottom horizons was due to its preferential adsorption on Fe and Mn oxides, relative to other REEs. Although both natural and anthropogenic activi-ties influence the geochemical behaviors of REEs in soils, enrichment or mobility of REEs is low in the natural wetland soil core of the San-jiang Plain. 相似文献
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