Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula w...Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula was further deduced to quantitatively analyze the influence of the volume fraction of aggregate, ITZ thickness and the maximum aggregate diameter on the overlapping degree between neighboring ITZ. The volume of ITZ was quantitatively calculated in actual concrete by comparing the nearest surface function formula with an approximate method, that is the surface area of the aggregates multiplied by the uniform thickness of the ITZ layers. The results showed that the influencing order of these three factors on the overlapping degree between neighboring ITZ in turn was the interface thickness, aggregate volume fraction and the maximum aggregate diameter; As long as the interface thickness 50 μm and the aggregate volume fraction 50%, the calculated error between two methods mentioned above is about 10 %.展开更多
Structural transfer zones in a half-graben rift basin play a significant role in controlling sandy sediments and providing a target for hydrocarbon exploration. Previous studies have classified the transfer zone in la...Structural transfer zones in a half-graben rift basin play a significant role in controlling sandy sediments and providing a target for hydrocarbon exploration. Previous studies have classified the transfer zone in lacustrine environments into two different patterns: synthetic approaching transfer zones and synthetic overlapping transfer zones. However, the evolution of the depositional pattern and the controlling factors of the above transfer zones are still unclear. In the Fushan Sag, the northern South China Sea, an overlapping transfer zone developed in the early Eocene Epoch, while a synthetic approaching transfer zone developed in the late Eocene, due to tectonic uplift. This evolutionary process provided an opportunity to study the stacking pattern of strata architectural variability and facies distribution in the structural transfer zone of the Eocene lacustrine basin. In this study, following the indications of the oriented sedimentary structures in core samples and heavy mineral assemblages of 18 wells, the evolution of the paleo-hydrodynamic distribution during the early and late Eocene has been reconstructed. The sequence-stratigraphy was then divided and the sand body parameters calculated, according to the seismic data and well log interpretations. During the early Eocene, the lake level was at a low stand, the faults broken displacement in the East block being over 50 m. The prograding delta and turbidites are oriented perpendicular to the structural transfer zone. According to the quantitative analysis of the flow rate and the depositional parameters, we speculate that gravity transportation of the sediment and the sediment-supply are the dominating factors during this period. Up to the late Eocene, the rising lake level and the decreased fault displacement leads the flow to divert to a NE-direction, resulting in it being parallel to the axis of the transfer zone. Thus, we speculate that the accommodation space is predominant in this period. In comparison with the above two periods, a braided river delta with an isolated sand body and turbidites developing in the deep area is prominent in the overlapping transfer zone, while a meandering river delta is characteristic of the synthetic approaching transfer zone.展开更多
森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特...森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特征进行了对比分析。结果表明:处于森林演替不同阶段的交错带,在由阔叶林、针阔叶混交林到针叶林的演替过程中,Shannon-W e iner多样性指数、M arga lef丰富度指数均表现出单峰变化趋势,在演替中后期的针阔叶混交林阶段,指数值最高。S im pson优势度指数则表现出凹形变化,不同于多样性、丰富度指数,在演替中后期,达到最低值。P ie lou均匀度指数表现出下降趋势。交错带内群落与相邻群落相比,Shannon-W e iner多样性指数较高,具有高的物种多样性,边际效应表现为正效应。M arga lef丰富度指数变化与Shannon-W e iner多样性指数变化不一致,只在一定程度上证明了边际正效应的影响。两指数共同反映出研究地区的森林交错带内群落具有较高的物种多样性。展开更多
基金Funded by the National Basic Research Program of China (No.2009CB623203)National High-tech R&D Program of China (No.2008AA030794)Postgraduates Research Innovation in University of Jiangsu Province in China (No.CX10B-064Z)
文摘Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula was further deduced to quantitatively analyze the influence of the volume fraction of aggregate, ITZ thickness and the maximum aggregate diameter on the overlapping degree between neighboring ITZ. The volume of ITZ was quantitatively calculated in actual concrete by comparing the nearest surface function formula with an approximate method, that is the surface area of the aggregates multiplied by the uniform thickness of the ITZ layers. The results showed that the influencing order of these three factors on the overlapping degree between neighboring ITZ in turn was the interface thickness, aggregate volume fraction and the maximum aggregate diameter; As long as the interface thickness 50 μm and the aggregate volume fraction 50%, the calculated error between two methods mentioned above is about 10 %.
基金sponsored by the National Natural Science Foundation of China(No.41572080)the Major State Science and Technology Research Program(No.2016ZX05024002-002)China Scholarship Council(CSC)(No.201906400071)。
文摘Structural transfer zones in a half-graben rift basin play a significant role in controlling sandy sediments and providing a target for hydrocarbon exploration. Previous studies have classified the transfer zone in lacustrine environments into two different patterns: synthetic approaching transfer zones and synthetic overlapping transfer zones. However, the evolution of the depositional pattern and the controlling factors of the above transfer zones are still unclear. In the Fushan Sag, the northern South China Sea, an overlapping transfer zone developed in the early Eocene Epoch, while a synthetic approaching transfer zone developed in the late Eocene, due to tectonic uplift. This evolutionary process provided an opportunity to study the stacking pattern of strata architectural variability and facies distribution in the structural transfer zone of the Eocene lacustrine basin. In this study, following the indications of the oriented sedimentary structures in core samples and heavy mineral assemblages of 18 wells, the evolution of the paleo-hydrodynamic distribution during the early and late Eocene has been reconstructed. The sequence-stratigraphy was then divided and the sand body parameters calculated, according to the seismic data and well log interpretations. During the early Eocene, the lake level was at a low stand, the faults broken displacement in the East block being over 50 m. The prograding delta and turbidites are oriented perpendicular to the structural transfer zone. According to the quantitative analysis of the flow rate and the depositional parameters, we speculate that gravity transportation of the sediment and the sediment-supply are the dominating factors during this period. Up to the late Eocene, the rising lake level and the decreased fault displacement leads the flow to divert to a NE-direction, resulting in it being parallel to the axis of the transfer zone. Thus, we speculate that the accommodation space is predominant in this period. In comparison with the above two periods, a braided river delta with an isolated sand body and turbidites developing in the deep area is prominent in the overlapping transfer zone, while a meandering river delta is characteristic of the synthetic approaching transfer zone.
文摘森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特征进行了对比分析。结果表明:处于森林演替不同阶段的交错带,在由阔叶林、针阔叶混交林到针叶林的演替过程中,Shannon-W e iner多样性指数、M arga lef丰富度指数均表现出单峰变化趋势,在演替中后期的针阔叶混交林阶段,指数值最高。S im pson优势度指数则表现出凹形变化,不同于多样性、丰富度指数,在演替中后期,达到最低值。P ie lou均匀度指数表现出下降趋势。交错带内群落与相邻群落相比,Shannon-W e iner多样性指数较高,具有高的物种多样性,边际效应表现为正效应。M arga lef丰富度指数变化与Shannon-W e iner多样性指数变化不一致,只在一定程度上证明了边际正效应的影响。两指数共同反映出研究地区的森林交错带内群落具有较高的物种多样性。
