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Changing provenance of late Cenozoic sediments in the Jianghan Basin

Geoscience Frontiers 2015年第4期6卷 605-615页

作者： Lei Shao shengyuan yuan Chang'an Li Chunguo Kang Wenjing Zhu Yindi Liu Jietao Wang Wuhan Center of Geological Survey China Geological Survey Faculty of Earth Sciences China University of Geosciences College of Urban Planning & Environment Science Xuchang University State Key Laboratory of Biogeology and Environmental Geology Institute of Geophysics & Geomatics China University of Geosciences Hubei Institute of Geological Sciences

The Yangtze River is one of the most important components of the East Asia river system. In this study, sediments in the Jianghan Basin, middle Yangtze River, were selected for trace element and rare earth element （REE） measurements, in order to decipher information on the change of sediment provenance and evolution of the Yangtze River. According to the elemental variations, the late Cenozoic sediments of the Jianghan Basin could be divided into four parts. During 2.68-2,28 Ma and 1.25-0 Ma, proveJ nance of the sediments was consistent, whereas sediments were derived from variable sources during 2.28-1.25 Ma. Comparison of the elemental compositions between the Pliocene and Quaternary sediments revealed a change in sediment source from a more felsic source area to a more basic source area around the Pliocene--Quaternary boundary. Input from the Emeishan LIP should account for this provenance change, Based on the provenance analysis of sediments in the Jianghan Basin, we infer that the Yangtze River developed into a large river with its drainage basin extended to the Emeishan LIP no later than the Pliocene-Quaternary boundary.

关键词： Yangtze River Jianghan Basin Trace element REE Provenance

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A verifiable low-level concurrent programming model based on colored Petri nets

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Science China(Information Sciences) 2011年第10期54卷 2013-2027页

作者： WANG shengyuan & DONG yuan Department of Computer Science and Technology,Tsinghua University,Beijing 100084,China Department of Computer Science and Technology Tsinghua University Beijing China

Concurrent programs written in a machine-level language are being used in many areas,but the verification of such programs brings various new challenges to the programming language *** of existing contributions on verifying the safety properties of concurrent programs are for high-level languages,specifications,or calculi in the *** to the lack of abstraction at a low level,additional work is needed to extend these methods to machine-level *** paper describes an approach to integrate Petri nets into low-level concurrent programs to form a new programming model (abstract machine).A program in the programming model is a restricted version of colored Petri net,with transitions colored by assembly codes for machine-level threads,and places colored by shared data consisting of memory locations or *** analysis and verification approaches for usual Petri nets can be applied indirectly for such a low-level concurrent program.

关键词： low-level concurrent programs colored Petri nets abstract machine verification

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延安文艺歌词创作的历史与审美特征——以《解放日报》所刊歌曲为中心

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当代文坛 2021年第5期 92-98页

作者：袁盛勇邱跃强陕西师范大学文学院

延安文艺是现代中国文化史上富有精神魅力的文艺形态。延安文艺中歌词的创作具有鲜明的历史阶段性特征,歌词中所表达的对于普通劳动者和劳动之美的颂赞,以及其所具有的信仰性内涵都真实而热切地存在着。延安文艺是一种真实的历史和艺术... 详细信息

延安文艺是现代中国文化史上富有精神魅力的文艺形态。延安文艺中歌词的创作具有鲜明的历史阶段性特征,歌词中所表达的对于普通劳动者和劳动之美的颂赞,以及其所具有的信仰性内涵都真实而热切地存在着。延安文艺是一种真实的历史和艺术存在,人们可以从中汲取精神的力量。

关键词：延安文艺歌词《解放日报》历史审美

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城市化进程中城郊耕地土壤重金属的含量及其分布特征

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贵州农业科学 2014年第7期42卷 197-201页

作者：袁胜元闫慧许昌学院城乡规划与园林学院河南许昌461000 黄土与第四纪地质国家重点实验室陕西西安710075

为明确城市化进程对城郊土壤质量的影响,以许昌市城郊耕地表层土壤为研究对象,利用X射线荧光光谱仪测定土壤重金属含量,在此基础上采用主成分分析和相关分析方法对Cr、Mn、Co、Ni、Cu、Zn、As和Pb等8种重金属元素的含量及空间分布特征,... 详细信息

为明确城市化进程对城郊土壤质量的影响,以许昌市城郊耕地表层土壤为研究对象,利用X射线荧光光谱仪测定土壤重金属含量,在此基础上采用主成分分析和相关分析方法对Cr、Mn、Co、Ni、Cu、Zn、As和Pb等8种重金属元素的含量及空间分布特征,来源及其相互关系进行研究。结果表明:1)Cr、Cu、Zn和Pb的含量分别为河南省土壤背景值的1.11倍、1.23倍、1.41倍和1.31倍,除个别样点外,4种元素的整体超标量均较小,但在研究区内空间分布差异较大。2)Ni、Cr、Cu、Zn和Pb均具有明显的高值带和高值区,而Co、As和Mn的含量接近于河南省土壤背景值,且分布较均匀,空间差异不大。3)Mn、Ni、As和Co的含量主要受成土母质的影响,Cr、Cu和Pb除受成土母质影响外可能还受人为因素的影响,Zn的含量则主要受交通干道分布影响。元素间不同的相关性、方差贡献率及与背景值的差异说明,Ni-Mn-As-Co、CrCu-Pb和Zn的来源各不相同。

关键词：重金属土壤污染城郊耕地许昌河南

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