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本文在文献[1]的基础上,记述了后石井这套石英-生物砂屑灰岩的物质成分、沉积结构和成岩作用特征,并与当地的现代海滩砂、海岸沙丘砂作了对比,进一步讨论了它们的成因与物质来源问题。作者认为,它们是大气降水胶结海岸沙丘砂所形成的海岸沙丘岩,是中全新世末东北季风吹扬附近海滩砂再堆积的结果。  相似文献   
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福建莆田海岸沙丘岩——Ⅰ.沉积构造与古风   总被引:8,自引:0,他引:8  
福建莆田后石井海岸沙丘岩由三个沙脊组成。本文记述了这些沙脊的形状与沉积构造,并在讨论其成因的基础上重建了古沙丘类型与古风向。本文认为,它们是中全新世末盛行的东北季风吹扬海滩沉积物再堆积所形成的有植被沙丘与风影沙丘,古今风向未发生明显的变化。  相似文献   
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Carbonate eolianites in Houshijing, Putian, Fujian, consist of three sand ridges. The geometry and sedimentary structures of these ridges are described here, and their paleodune types and the paleowind directions are reconstructed on the basis of discussion of genesis. The authors consider that they were vegetated longitudinal dunes or sand drifts and wind shadow dunes or sand shadows which were formed by reworking of adjacent beach sand by prevailing northeast monsoon during the latest Middle Holocene. The wind directions in the past and at present do not appear to have obviously changed.  相似文献   
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 在理论分析分数比脉冲变压器输出脉冲上升时间与变压器次级绕组匝数、磁芯截面积和伏秒积等参数关系的基础上,设计建造了一台初次级等效比为1∶43.4分数比脉冲变压器,等效到次级的漏感为157.3 μH,分布电容为412.4 pF。低电压实验得到负载上的脉冲上升时间为894 ns,高电压实验得到负载上的脉冲上升时间为917 ns,电压幅值42.7 kV,表明所设计建造的分数比脉冲变压器达到了设计要求。  相似文献   
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本文叙述了在EPA-74脉冲线加速器上开展的等离子体融蚀断路开关(PEOS)实验研究工作。实验中采用三个等离子体发射枪,磁绝缘传输线(MITL)的阻抗为133Ω。实验表明PEOS可以降低二极管预脉冲电压。使束的焦斑变小,增大X射线剂量。预脉冲电压由原来的60kV降低到10kV,靶正前1米处X射线剂量增加了77%。  相似文献   
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On the basis of Ref. [1] entitled "Carbonate eolianites in Putian, Fujian (Ⅰ)——Sedimentary structures and paleowinds", the sediment composition, sedimentary textures and diagenesis of the quartz-calcarenites in Houshijing, Putian, Fujian are described here and compared with those of adjacent modern dune and beach sands, and their genesis and sources of sediment are discussed further. The authors consider that they are carbonate eolianites which were formed by coastal dune sand derived from reworking of adjacent beach sand by prevailing northeast monsoon winds and then cemented by freshwater subaerially during the end of the Middle Holocene.  相似文献   
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