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天津市PM_(2.5)中氮含量及同位素的昼夜及季节变化 被引量:7
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作者 董志超 徐占杰 +5 位作者 王爽 李培森 赵雪琰 傅平青 刘丛强 Chandra Mouli Pavuluri 《中国环境科学》 EI CAS CSCD 北大核心 2021年第3期1014-1023,共10页
为研究天津市大气气溶胶中氮的来源,分析了2016年夏、冬两季昼夜采集的细颗粒物气溶胶(PM_(2.5))中无机离子浓度和氮同位素组成(δ^(15)N).结果显示:天津市冬季平均PM_(2.5)质量浓度(207μg/m^(3))远高于夏季(40.1μg/m^(3)),冬季PM_(2... 为研究天津市大气气溶胶中氮的来源,分析了2016年夏、冬两季昼夜采集的细颗粒物气溶胶(PM_(2.5))中无机离子浓度和氮同位素组成(δ^(15)N).结果显示:天津市冬季平均PM_(2.5)质量浓度(207μg/m^(3))远高于夏季(40.1μg/m^(3)),冬季PM_(2.5)的δ^(15)N值(+5.1‰)低于夏季(+10.7‰),即夏季PM_(2.5)较冬季更富集15N;夏季PM_(2.5)中NH^(4+)的平均浓度高于c(NO_(3)^(–)),但是冬季NO_(3)^(–)浓度最高,其次是c(NH^(4+))>c(SO_(4)^(2–));此外,通过对比昼夜样品,夏季PM_(2.5)中氮含量和氮同位素组成在昼夜均表现出明显差异,而冬季不明显.结果表明,天津市夏季气溶胶中含氮化合物在昼夜受海陆风的影响,即白天受海洋气溶胶影响较大而夜间则为陆源气溶胶物质影响,然而冬季受东亚季风的影响削弱了海陆风对海陆间大气气溶胶的交换作用,且在冬季化石燃料燃烧源氮贡献较大. 展开更多
关键词 大气气溶胶 氮同位素 海陆风 天津
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Soil Heavy Metal Pollution Around the Dabaoshan Mine,Guangdong Province,China 被引量:68
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作者 ZHOU Jian-Min DANG Zhi +1 位作者 CAI Mei-Fang liu cong-qiang 《Pedosphere》 SCIE CAS CSCD 2007年第5期588-594,共7页
Soil contamination in the vicinity of the Dabaoshan Mine, Guangdong Province, China, was studied through determi- nation of total concentrations and chemical speciation of the toxic metals, Cu, Zn, Cd, and Pb, using i... Soil contamination in the vicinity of the Dabaoshan Mine, Guangdong Province, China, was studied through determi- nation of total concentrations and chemical speciation of the toxic metals, Cu, Zn, Cd, and Pb, using inductively coupled plasma mass spectrometry. The results showed that over the past decades, the environmental pollution was caused by a combination of Cu, Zn, Cd, and Pb, with tailings and acid mine drainage being the main pollution sources affecting soils. Significantly higher levels (P ≤ 0.05) of Cu, Zn, Cd, and Pb were found in the tailings as compared with paddy, garden, and control soils, with averages of 1486, 2516, 6.42, and 429 mg kg^-1, respectively. These metals were continuously dispersed downstream from the tallings and waste waters, and therefore their concentrations in the paddy soils were as high as 567, 1 140, 2.48, and 191 mg kg^-1, respectively, being significantly higher (P ≤ 0.05) as compared with those in the garden soils. The results of sequential extraction of the above metals from all the soil types showed that the residual fraction was the dominant form. However, the amounts of metals that were bound to Fe-Mn oxides and organic matter were relatively higher than those bound to carbonates or those that existed in exchangeable forms. As metals could be transformed from an inert state to an active state, the potential environmental risk due to these metals would increase with time. 展开更多
关键词 chemical speciation combined pollution index (CPI) contaminated soil heavy metals
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Location Prediction of Blind Ore bodies in Shuijingtun Gold Mine, Zhangjiakou, China
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作者 WEI Jun-hao liu cong-qiang +1 位作者 ZHAO Zhi-qi LI Jian-wei 《Journal of Central South University》 SCIE EI CAS 2000年第3期124-128,共5页
By analyzing the metallogenic conditions and prospecting marks of F 8 fault belt in Shiujingtun Gold Mine, the geochemical samples were collected along F 8 fault belt and prospecting profile normal to the F 8 fault be... By analyzing the metallogenic conditions and prospecting marks of F 8 fault belt in Shiujingtun Gold Mine, the geochemical samples were collected along F 8 fault belt and prospecting profile normal to the F 8 fault belt. Gold and its indicator elements were tested with X ray fluorescence spectrometry and the content distribution diagram of Au, Ag, Hg and As along the F 8 fault belt was performed. The geochemical primary halo model and the Grey system model of F 8 fault belt are established. With these element distribution features and models, the blind ore bodies in the F 8 fault belt were predicted. Engineering prospect shows that the industrial orebodies have been discovered and the prediction results are dependable. 展开更多
关键词 location PREDICATION BLIND ORE BODIES geochemical primary HALO grey system model
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结合k-均值聚类缓解行人检测正负样本不平衡问题
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作者 刘丛强 王浩森 +2 位作者 范虹 葛成鹏 杨建盛 《河北建筑工程学院学报》 CAS 2020年第4期161-166,共6页
针对行人检测中正负样本不平衡问题,使用构建了FPN(Feature Pyramid Networks)的Faster R-CNN进行检测,并在训练Faster R-CNN的RPN(Region Proposal Network)时使用k-均值聚类算法对行人数据集进行聚类得到的适应于行人检测的锚框比例,... 针对行人检测中正负样本不平衡问题,使用构建了FPN(Feature Pyramid Networks)的Faster R-CNN进行检测,并在训练Faster R-CNN的RPN(Region Proposal Network)时使用k-均值聚类算法对行人数据集进行聚类得到的适应于行人检测的锚框比例,最后在CityPersons数据集上测试。实验结果表明,使用更适应于行人的锚框比例有效缓解了行人检测正负样本不平衡的问题,并且能生成相比设置密集比例的方法稀疏但总体质量更高的正样本,能更有效的提升行人检测的精度。 展开更多
关键词 行人检测 K-均值 锚框 区域建议网络 卷积神经网络
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Source Identification of Sulfur in Uncultivated Surface Soils from Four Chinese Provinces 被引量:1
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作者 XIAO Hua-Yun LI Nan liu cong-qiang 《Pedosphere》 SCIE CAS CSCD 2015年第1期140-149,共10页
The analysis of stable isotopes of sulfur(δ34S) is a useful tool for identifying sources of sulfur in soils. Concentrations and sulfur(S)isotopes of water-soluble sulfate(WSS), adsorbed sulfate(AS), residual sulfur(R... The analysis of stable isotopes of sulfur(δ34S) is a useful tool for identifying sources of sulfur in soils. Concentrations and sulfur(S)isotopes of water-soluble sulfate(WSS), adsorbed sulfate(AS), residual sulfur(RS), and total sulfur(TS) in uncultivated surface soils of four Chinese provinces were systematically analyzed for identifying sources of S in the soils. Green and healthy mosses(Haplocladium microphyllum) were sampled as bioindicators. The mean WSS concentration(27.8 ± 23.4 mg kg-1) in the surface soils was lower than those of AS(101.4 ± 57.0 mg kg-1) and RS(381.5 ± 256.7 mg kg-1). The mean δ34S values of WSS and AS were very similar(about2.0‰), lower than those of RS(8.0‰) and TS(6.1‰). A significant linear correlation was found between the δ34S values of AS and WWS(y = 1.0002x- 0.0557, P < 0.0001), indicating that sulfate adsorption in the soils did not markedly fractionate S. All S species in the soils of Guizhou Province were characterized by the lowest δ34S values, consistent with the most34S-depleted rainwater sulfate reported at Guiyang of Guizhou Province. The δ34S values of sulfate in mosses and rainwater previously reported were significantly linearly correlated with those of both WWS and AS in surface soils, suggesting that atmospheric S input was an important source for soil WSS and AS. However, there were no significant correlations between isotopic composition of rainwater sulfate and RS or TS.The slopes of all these significant linear correlations(soil/rainwater or soil/moss isotopic ratio) were 0.4–0.6, indicating that inorganic sulfate in the surface soils should be a result of mixing of deposited atmospheric sulfate with a more34S-depleted sulfate component possibly from mineralization of RS. 展开更多
关键词 adsorbed sulfate atmospheric input BIOINDICATORS isotopic composition moss residual sulfur water-soluble sulfate
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