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991.
Weihua Wu Shijin Xu Jiedong Yang Hongwei Yin Huayu Lu Kaijun Zhang 《Chemical Geology》2010,269(3-4):406-413
We systematically collected 40 modern clastic sediment samples from rivers in different tectonic units of the Tibetan Plateau and measured their Sr–Nd isotopic compositions. The isotopic characteristics provide insight into the controversial paleo-tectonic affinity of terranes of the Tibetan Plateau and the provenance of Songpan–Ganzi flysch complex. The Qilian Terrane and Himalaya Terrane have more negative εNd(0) values (from ? 14.3 to ? 11.8 and from ? 20.64 to ? 13.26, respectively) and high 87Sr/86Sr values (from 0.719674 to 0.738818 and from 0.721020 to 0.824959, respectively), reflecting old and mature continental crust origin of these two terranes. The southern Lhasa Terrane is more radiogenic in εNd(0) values (from ? 8.82 to ? 3.8) and low in 87Sr/86Sr values (from 0.711504 to 0.719489), implying the combined impact of the Neo-Tethys mantle and Himalaya old continental crust. Sr–Nd isotopic compositions of the Qilian Terrane are similar to those in the Yangtze Craton, indicating that the Qilian Terrane was probably separated from the Yangtze Craton. Sr–Nd isotopic characteristics of the Songpan–Ganzi Terrane are similar to the Yangtze Craton and are remarkably different to those in the North China Craton, eastern Kunlun–Qaidam and the central Qiangtang metamorphic belt, implying that the widely distributed flysch complex of the Songpan–Ganzi Terrane was sourced from the Yangtze Craton. 相似文献
992.
993.
994.
A hominin maxilla, discovered in 1983 in Chaoxian County, Anhui Province, eastern China represents one of several Asian hominins dating to the late Middle Pleistocene. Although the maxilla and associated occipital have been described, no detailed study of the dentition has been made. This study provides metrical and morphological information on the Chaoxian dentition and places it into a larger Middle to Late Pleistocene context. Implications for the taxonomy of Middle Pleistocene hominins are discussed. 相似文献
995.
Impacts of hydrological conditions on peatland soil enzyme activities and phenolic concentrations were investigated using
peat cores from two typical peatlands, the forest swamp and the marsh in North-east China, under water level manipulation
in the laboratory. The results indicated varied impacts of dry and waterlogged conditions on soil enzyme activities, depending
on the confounding factors including the peatland types and the variation frequency of hydrological conditions. Carbon-related
enzyme activities, phenol oxidase and β-glucosidase, were much higher in the marsh than in the forest swamp. On the contrary,
phenolic concentration was measured to be much higher in the latter. Soil enzyme activities and phenolic concentrations were
found to vary between the two peatlands, much more remarkably than within the individual peatlands caused by the changes in
the water level. The negative relationship or inconspicuous correlation between phenolics and phenol oxidase was found to
vary with specific soil conditions. These results implied that the enzyme activities and phenolic concentrations might be
related to the developmental stages or the types of wetlands more than to hydrological conditions. 相似文献
996.
997.
Wu Jianhua Zhao Yu Yu Mengjuan Zou Xiaoxiang Xiong Jiaqi Hu Xiang 《Journal of Geographical Systems》2023,25(2):265-289
Journal of Geographical Systems - Object matching is a key technology for map conflation, data updating, and data quality assessment. This article proposed a new Voronoi diagram-based approach for... 相似文献
998.
Journal of Oceanology and Limnology - Magnetotactic bacteria (MTB) are morphologically and phylogenetically diverse prokaryotes commonly able to produce magnetic nanocrystals within intracellular... 相似文献
999.
学生反馈是评估高等院校课堂教学质量的重要指标。目前,对学生反馈的问卷仅进行主观理解和简单统计,无法提供准确定量的分析和支持依据。使用非线性决策树,对近3年本科必修双语课程《数字图像处理》的学生评教问卷进行数据挖掘,首先将其分成3类和10个不同输入,然后通过数据预处理、模型选择和建模,最后构建树状模型对其进行分析。分析结果符合对于该课程学生反应和争议较大的问题预期,为课程设计提供定量有效的教学分析工具。 相似文献
1000.