In the South Yellow Sea Basin,Mesozoic–Paleozoic marine strata are generally well developed with large thickness,and no substantial breakthroughs have been made in hydrocarbon exploration.Through research,it is belie...In the South Yellow Sea Basin,Mesozoic–Paleozoic marine strata are generally well developed with large thickness,and no substantial breakthroughs have been made in hydrocarbon exploration.Through research,it is believed that the Upper Permian–Lower Triassic can be regarded as a long-term base-level cycle.Based on drilling data,characteristics of the lithology–electric property combination cyclicity,and the special lithology,the long-term base-level cycle was divided into five medium-term base-level cycles(MC1–MC5).On this basis,the Permian–Triassic sedimentary systems and their filling model were analyzed in accordance with the change of base-level cycle and transition of sedimentary environment,as well as characteristics of the drilling sedimentary facies and seismic facies.The results show that there were six sedimentary systems(fluvial,delta,tidal flat,open platform,restricted platform,and continental shelf)developed in the Upper Permian–Lower Triassic,the sedimentary systems were distributed such that the water was deep in the northwest and shallow in the southeast,and there were two base-level cycle filling models(a relatively stable tidal flat facies and a rapidly transgressive continental shelf facies to stable platform facies)developed in the Upper Permian–Lower Triassic.These models can provide a basis for evaluation of the Mesozoic–Paleozoic hydrocarbon geology in the South Yellow Sea Basin.展开更多
A number of aftershocks of the May 10th 1997, Zirkuh (Ghaen-Birjand) destructive earthquake have been used to investigate the anisotropy in the upper crust by observing shear wave splitting. Particle motion diagram an...A number of aftershocks of the May 10th 1997, Zirkuh (Ghaen-Birjand) destructive earthquake have been used to investigate the anisotropy in the upper crust by observing shear wave splitting. Particle motion diagram and aspect ratio methods were used as two different approaches to obtain splitting parameters. Clear shear wave splitting was observed on the records of the selected aftershocks, indicating that the media in the region was highly anisotropic. By using particle motion method, the direction of fast shear wave was found 22N19E, while the delay time between the fast and slow shear waves was obtained to be (6516) ms. By aspect ratio method, the direction of fast shear wave was determined to be 35N18E and the delay time between fast and slow shear waves was found to be (4910) ms. For a simple horizontal layer with a thickness about 5 km and uniformly distributed anisotropy, a stress aligned cracks model was used and the result was interpreted in terms of vertical aligned cracks in the direc-tion of N22E, having a density about 0.01. It is assumed that cracks are fluid-filled since they are located in the upper crust. Finally, by using Hudson cracks model for three crack densities 0.005, 0.01, 0.03, the velocity curves of shear wave were plotted as a function of angle between the symmetrical axis of cracks and the azimuth of source to receiver. It was concluded that when shear wave was polarized parallel to the crack surface, the velocity was uniform, but the velocity curve varied clearly if shear wave was polarized perpendicular to the crack surface.展开更多
Modern human has different body proportion from early hominids and great apes.Comparing with others,in general,modern human adults have relatively long lower limb and heavier body weight.Since the lower limbs provide ...Modern human has different body proportion from early hominids and great apes.Comparing with others,in general,modern human adults have relatively long lower limb and heavier body weight.Since the lower limbs provide support to the whole body and play an important role in walking,it is proposed that the ratio of the lower limb to the whole body for modern human could be beneficial to bipedal walking.This study tried to estimate the muscle parameters of the lower limb in walking for the subjects with various body proportions.Using a simplified musculoskeletal model,some muscle parameters of the lower limb,e.g.muscle force,stress,work and power,were estimated for modern human adult,child,AL 288-1(the fossil specimens of Australopithecus afarensis,3.18 million years old)and apes.The results show that with the body proportion modern human adult spends less muscle work and power in walking than other subjects.The results imply that using the cost of transport(i.e.the muscle work of the lower limb per unit of displacement)as the criteria,the early hominids,if their body proportions were structurally similar to AL 288-1,could evolve towards what modern human adult looks like,in order to save energy during bipedal walking.展开更多
基金Projects(41506080,41702162)supported by the National Natural Science Foundation of ChinaProjects(DD20160152,DD20160147,GZH200800503)supported by China Geological Survey+1 种基金Projects(XQ-2005-01,2009GYXQ10)supported by China Ministry of Land and ResourcesProject(201602004)supported by the Postdoctoral Innovation Foundation of Shandong Province,China
文摘In the South Yellow Sea Basin,Mesozoic–Paleozoic marine strata are generally well developed with large thickness,and no substantial breakthroughs have been made in hydrocarbon exploration.Through research,it is believed that the Upper Permian–Lower Triassic can be regarded as a long-term base-level cycle.Based on drilling data,characteristics of the lithology–electric property combination cyclicity,and the special lithology,the long-term base-level cycle was divided into five medium-term base-level cycles(MC1–MC5).On this basis,the Permian–Triassic sedimentary systems and their filling model were analyzed in accordance with the change of base-level cycle and transition of sedimentary environment,as well as characteristics of the drilling sedimentary facies and seismic facies.The results show that there were six sedimentary systems(fluvial,delta,tidal flat,open platform,restricted platform,and continental shelf)developed in the Upper Permian–Lower Triassic,the sedimentary systems were distributed such that the water was deep in the northwest and shallow in the southeast,and there were two base-level cycle filling models(a relatively stable tidal flat facies and a rapidly transgressive continental shelf facies to stable platform facies)developed in the Upper Permian–Lower Triassic.These models can provide a basis for evaluation of the Mesozoic–Paleozoic hydrocarbon geology in the South Yellow Sea Basin.
文摘A number of aftershocks of the May 10th 1997, Zirkuh (Ghaen-Birjand) destructive earthquake have been used to investigate the anisotropy in the upper crust by observing shear wave splitting. Particle motion diagram and aspect ratio methods were used as two different approaches to obtain splitting parameters. Clear shear wave splitting was observed on the records of the selected aftershocks, indicating that the media in the region was highly anisotropic. By using particle motion method, the direction of fast shear wave was found 22N19E, while the delay time between the fast and slow shear waves was obtained to be (6516) ms. By aspect ratio method, the direction of fast shear wave was determined to be 35N18E and the delay time between fast and slow shear waves was found to be (4910) ms. For a simple horizontal layer with a thickness about 5 km and uniformly distributed anisotropy, a stress aligned cracks model was used and the result was interpreted in terms of vertical aligned cracks in the direc-tion of N22E, having a density about 0.01. It is assumed that cracks are fluid-filled since they are located in the upper crust. Finally, by using Hudson cracks model for three crack densities 0.005, 0.01, 0.03, the velocity curves of shear wave were plotted as a function of angle between the symmetrical axis of cracks and the azimuth of source to receiver. It was concluded that when shear wave was polarized parallel to the crack surface, the velocity was uniform, but the velocity curve varied clearly if shear wave was polarized perpendicular to the crack surface.
基金Supported in part by the grants fromthe BiotechnologyBiological Sciences Research Council,the Leverhulme Trustthe Natural Environment Research Council,U.K.
文摘Modern human has different body proportion from early hominids and great apes.Comparing with others,in general,modern human adults have relatively long lower limb and heavier body weight.Since the lower limbs provide support to the whole body and play an important role in walking,it is proposed that the ratio of the lower limb to the whole body for modern human could be beneficial to bipedal walking.This study tried to estimate the muscle parameters of the lower limb in walking for the subjects with various body proportions.Using a simplified musculoskeletal model,some muscle parameters of the lower limb,e.g.muscle force,stress,work and power,were estimated for modern human adult,child,AL 288-1(the fossil specimens of Australopithecus afarensis,3.18 million years old)and apes.The results show that with the body proportion modern human adult spends less muscle work and power in walking than other subjects.The results imply that using the cost of transport(i.e.the muscle work of the lower limb per unit of displacement)as the criteria,the early hominids,if their body proportions were structurally similar to AL 288-1,could evolve towards what modern human adult looks like,in order to save energy during bipedal walking.
