The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geologic...The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geological setting.Here,in this study,new sporopollen data from three boreholes(GK138,GK111 and GK95)in the coastal plain of Laizhou Bay,Bohai Sea were investigated,and the pollen spectrum since the late middle Pleistocene was established as six sporopollen assemblage zones(Ⅰ-Ⅵ),i.e.,Pinus-Quercus-Artemisia,Gramineae-Artemisia-Chenopodiaceae,Picea-Pinus-QuercusArtemisia,Picea-Pinus-Betula-Gramineae-Artemisia,Picea-Pinus-Cupressaceae-Chenopodiaceae and Pinus-Quercus-Gramineae-Artemisia-Chenopodiaceae.Combining with existing sedimentary successions and detailed radiocarbon dating results of the sediments from the three boreholes,paleovegetation and climatic evolution since the late middle Pleistocene were reconstructed.The findings revealed that climatic changes in this area since the late middle Pleistocene were characterized by alternating cold-arid and warmhumid conditions,which were well correlated with marine isotopic stages(MIS).The present study offers specific insight into the climatic dynamics in the North China Plain since the late middle Pleistocene and provides evidence of a clear link among the palynoflora in the area,the glacial-interglacial period climatedriven sea-level changes,and the marineδ^(18)O records.展开更多
The silicone rubber composites present remarkable mechanical properties due to the double network structure constructed with molecular network of matrix and filler network of silica.Nevertheless,the filler network str...The silicone rubber composites present remarkable mechanical properties due to the double network structure constructed with molecular network of matrix and filler network of silica.Nevertheless,the filler network structure and corresponding reinforcement mechanism are still under debate and need to be further probed with the aid of applicative advanced analysis techniques.Herein,small-angle neutron scattering(SANS)and synchrotron radiation X-ray nano-computed tomography(Nano-CT)techniques are employed to explore the evolution of filler networks of fumed,precipitated and sol-gel silica,respectively.Our studying results reveal the formation of filler network constructed by the interconnecting of branched silica aggregates.And the silica with highly associated structure,pertaining to amorphous morphology,small size,and large surface area,presents short distance and effective molecular chain bridge between aggregates,thus forming strong and steady filler networks.This work would provide deep-seated revisiting of filler networks and corresponding reinforcement mechanism and offer guidance for optimizing the mechanical properties of silicone rubber.展开更多
The Permian Taiyuan and Shanxi formations exposed in Shandong Province,eastern North China,contain abundant spores and pollen.In this study,a total of 42 genera and 146 species of spores and pollen from these Permian ...The Permian Taiyuan and Shanxi formations exposed in Shandong Province,eastern North China,contain abundant spores and pollen.In this study,a total of 42 genera and 146 species of spores and pollen from these Permian formations,native to northern China,are identified and related to the three epochs of the Permian Period(Cisuralian,Guadalupian,and Lopingian Epochs)as two assemblages:Assemblage I—the Laevigatosporites-Granulatisporites assemblage,inferred as the Cisuralian(~298.9-272.9 Ma);and,Assemblage II—the Gulisporites-Sinulatisporites assemblage,inferred as the Guadalupian(~272.9-259.1 Ma).Assemblage I represents growing ferns,whereas Assemblage II represents gymnosperms.The assemblage division and analysis indicated that the palaeoclimate of the study area during Early-Middle Permian time was dominated by warm and humid conditions,and later in the Middle Permian changed into moderately dry conditions.展开更多
基金supported by the Taishan Scholar Foundation of Shandong Province,China(Grant No.20190954)the National Natural Science Foundation of China(Grant No.32101373)+1 种基金the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2020QC050)the State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,CAS,China(Grant No.123104)。
文摘The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geological setting.Here,in this study,new sporopollen data from three boreholes(GK138,GK111 and GK95)in the coastal plain of Laizhou Bay,Bohai Sea were investigated,and the pollen spectrum since the late middle Pleistocene was established as six sporopollen assemblage zones(Ⅰ-Ⅵ),i.e.,Pinus-Quercus-Artemisia,Gramineae-Artemisia-Chenopodiaceae,Picea-Pinus-QuercusArtemisia,Picea-Pinus-Betula-Gramineae-Artemisia,Picea-Pinus-Cupressaceae-Chenopodiaceae and Pinus-Quercus-Gramineae-Artemisia-Chenopodiaceae.Combining with existing sedimentary successions and detailed radiocarbon dating results of the sediments from the three boreholes,paleovegetation and climatic evolution since the late middle Pleistocene were reconstructed.The findings revealed that climatic changes in this area since the late middle Pleistocene were characterized by alternating cold-arid and warmhumid conditions,which were well correlated with marine isotopic stages(MIS).The present study offers specific insight into the climatic dynamics in the North China Plain since the late middle Pleistocene and provides evidence of a clear link among the palynoflora in the area,the glacial-interglacial period climatedriven sea-level changes,and the marineδ^(18)O records.
基金the National Natural Science Foundation of China(Nos.11605171 and 21973076)Sichuan Science and Technology Program(No.2018GZ0155)+2 种基金Ph.D program Foundation of SWUST(No.18ZX7112)Longshan Program for Talents(SWUST,No.I8 LZXT11)the Project of State Key Laboratory of Environment-Friendly Energy Materials(SWUST,No.19FKSY16).
文摘The silicone rubber composites present remarkable mechanical properties due to the double network structure constructed with molecular network of matrix and filler network of silica.Nevertheless,the filler network structure and corresponding reinforcement mechanism are still under debate and need to be further probed with the aid of applicative advanced analysis techniques.Herein,small-angle neutron scattering(SANS)and synchrotron radiation X-ray nano-computed tomography(Nano-CT)techniques are employed to explore the evolution of filler networks of fumed,precipitated and sol-gel silica,respectively.Our studying results reveal the formation of filler network constructed by the interconnecting of branched silica aggregates.And the silica with highly associated structure,pertaining to amorphous morphology,small size,and large surface area,presents short distance and effective molecular chain bridge between aggregates,thus forming strong and steady filler networks.This work would provide deep-seated revisiting of filler networks and corresponding reinforcement mechanism and offer guidance for optimizing the mechanical properties of silicone rubber.
基金This study was supported by the Open Foundation for the Modern Key Laboratory of Paleontology and Stratigraphy,Nanjing Institute of Geology and Paleontology,Chinese Academy of Sciences(Grant No.123104).
文摘The Permian Taiyuan and Shanxi formations exposed in Shandong Province,eastern North China,contain abundant spores and pollen.In this study,a total of 42 genera and 146 species of spores and pollen from these Permian formations,native to northern China,are identified and related to the three epochs of the Permian Period(Cisuralian,Guadalupian,and Lopingian Epochs)as two assemblages:Assemblage I—the Laevigatosporites-Granulatisporites assemblage,inferred as the Cisuralian(~298.9-272.9 Ma);and,Assemblage II—the Gulisporites-Sinulatisporites assemblage,inferred as the Guadalupian(~272.9-259.1 Ma).Assemblage I represents growing ferns,whereas Assemblage II represents gymnosperms.The assemblage division and analysis indicated that the palaeoclimate of the study area during Early-Middle Permian time was dominated by warm and humid conditions,and later in the Middle Permian changed into moderately dry conditions.
