The formation of Danxia landscapes is too slow to be observed in our life time and the paleoclimates in which Danxia landscapes developed are significantly different from the present. Thus, this study adopted experime...The formation of Danxia landscapes is too slow to be observed in our life time and the paleoclimates in which Danxia landscapes developed are significantly different from the present. Thus, this study adopted experimental approaches to examine the lithological and paleoclimatic control on the formation of various landscape morphologies in the Mt. Danxiashan, South China. A total of 122 rock samples were collected from a range of Danxia landscape morphologies such as white spots, small and large through caves, honeycomb caves, horizontal grooves, natural bridges, stone pillars, and squama stones. Analyses of the collected samples were conducted in different kinds of experiments, including uniaxial mechanical strength testing; rock resistance against sulfuric acid erosion, freezing, and thawing; X-ray fluorescence spectrometry（XRF） analysis; inductively coupled plasma mass spectrometry（ICP-MS） analysis; and identification analysis under a polarizing microscope. The results indicated that the formation of the various Danxia landscape morphologies could result from one or more of the following processes： differential erosion due to lithological difference, chemical dissolution and recrystallization, freezing and thawing actions, acid corrosion, weathering, lateral erosion of river flows, and tectonic uplifts. Water erosion in humid monsoon climate and the alternations of intensive freezing and thawing actions in the Quaternary glacial stages and the interglacial stages could have had great influences on the formation of Danxia landscape topographies.展开更多
纤维金属层板(Fibre metal laminates,FMLs)具有优异的综合力学性能,现已成功应用于航空等领域。高速冲击性能是FMLs重要的力学性能指标之一,然而由于FMLs高速冲击破坏机制的复杂性,目前对其高速冲击性能的研究还处于起步阶段。鉴于此,...纤维金属层板(Fibre metal laminates,FMLs)具有优异的综合力学性能,现已成功应用于航空等领域。高速冲击性能是FMLs重要的力学性能指标之一,然而由于FMLs高速冲击破坏机制的复杂性,目前对其高速冲击性能的研究还处于起步阶段。鉴于此,本文在综述FMLs力学性能的基础上,重点从实验研究和有限元模拟等方面讨论了FMLs高速冲击性能研究现状,最后提出了FMLs力学性能现有研究中存在的一些问题和未来潜在的发展方向。展开更多
基金National Natural Science Foundation of China, No.41371204 No.41171163+6 种基金 No.41401216 National Science and Technology Basic Special Key Project, No.2013FY 11 1900 Foundation of State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, No.SKLLQG1206 No.SKLLQG1422 National Basic Science Personnel Training Project, No.J1103408 Foundation of Modern Analysis Center, Nanjing University, No.0422171010 Priority Academic Program Development of Jiangsu Higher Education Institutions, No.PAPD,Acknowledgements We appreciate the laboratory and field assistance of KONG Qingyou, LIU Di, YANG Li, WANG Xiaocui, FU Jingcheng, LIANG Guomin, MAO Xiaodong, FAN Dengfeng, LUO Jiehong, WU Huaan, TAN Ming, DAI Huibao, and XIE Zhangzhen.
文摘The formation of Danxia landscapes is too slow to be observed in our life time and the paleoclimates in which Danxia landscapes developed are significantly different from the present. Thus, this study adopted experimental approaches to examine the lithological and paleoclimatic control on the formation of various landscape morphologies in the Mt. Danxiashan, South China. A total of 122 rock samples were collected from a range of Danxia landscape morphologies such as white spots, small and large through caves, honeycomb caves, horizontal grooves, natural bridges, stone pillars, and squama stones. Analyses of the collected samples were conducted in different kinds of experiments, including uniaxial mechanical strength testing; rock resistance against sulfuric acid erosion, freezing, and thawing; X-ray fluorescence spectrometry（XRF） analysis; inductively coupled plasma mass spectrometry（ICP-MS） analysis; and identification analysis under a polarizing microscope. The results indicated that the formation of the various Danxia landscape morphologies could result from one or more of the following processes： differential erosion due to lithological difference, chemical dissolution and recrystallization, freezing and thawing actions, acid corrosion, weathering, lateral erosion of river flows, and tectonic uplifts. Water erosion in humid monsoon climate and the alternations of intensive freezing and thawing actions in the Quaternary glacial stages and the interglacial stages could have had great influences on the formation of Danxia landscape topographies.
文摘纤维金属层板(Fibre metal laminates,FMLs)具有优异的综合力学性能,现已成功应用于航空等领域。高速冲击性能是FMLs重要的力学性能指标之一,然而由于FMLs高速冲击破坏机制的复杂性,目前对其高速冲击性能的研究还处于起步阶段。鉴于此,本文在综述FMLs力学性能的基础上,重点从实验研究和有限元模拟等方面讨论了FMLs高速冲击性能研究现状,最后提出了FMLs力学性能现有研究中存在的一些问题和未来潜在的发展方向。
