We collected waveforms of a teleseismic event which occurred from January 2007 to October 2011 from 174 broadband seismic stations deployed in Hebei and its adjacent areas. Using the H-k stacking method,the average th...We collected waveforms of a teleseismic event which occurred from January 2007 to October 2011 from 174 broadband seismic stations deployed in Hebei and its adjacent areas. Using the H-k stacking method,the average thickness and Poisson's ratio of the crust are acquired. In order to obtain reliable receiver functions, the broadband seismograms of 488 teleseismic earthquakes occurring in the epicentral distance range from 30° to 90° with magnitudes larger than Mb6. 0 are collected. The results show that crustal thickness have conspicuous lateral heterogeneity and have good correlation to the regional geological tectonic features. Poisson ratio's value is equated with the global models estimates which fluctuate at about 0. 25. Crustal thickness has positive correlation to the topography and the Taihang Mountains form the transition zone of thick and thin crustal thickness. There is an obvious difference in crustal thickness beneath the north and south of the Shanxi earthquake zone and the Poisson ratio of Datong,Ningwu and Anze basins is greater than 0. 3. The crustal thickness beneath the Zhang-Bo( Zhangjiakou-Bohai Sea)earthquake zone decreases from west to north and its Poisson ratio shows conspicuous lateral heterogeneity. The thin crust and low Poisson ratio in the Huabei( North China)basin may correlate with the delamination of the North China craton.展开更多
Hydrogen-powered aircraft,as a cutting-edge exploration of clean-energy air transportation,impose more stringent requirements for lightweight hydrogen storage due to the limitations of aircraft weight and volume.Compo...Hydrogen-powered aircraft,as a cutting-edge exploration of clean-energy air transportation,impose more stringent requirements for lightweight hydrogen storage due to the limitations of aircraft weight and volume.Composite hydrogen storage cylinders have become one of the preferred solutions for hydrogen storage systems in hydrogen-powered aircraft due to their light weight and high strength.However,during the automated placement of high-stiffness thermoplastic composites(T700/PEEK),fibers may buckle or break in the head section.As the head radius decreases,the overlap of adjacent tows increases,resulting in an increase in the thickness of the polar pores,which is contrary to the light-weighting requirements.To solve this problem,this paper derives the trajectory algorithm as a manufacturing process limitation when thermoplastic fiber bundles are laid without wrinkles,provides a definition of the overlap rate between adjacent fibers,and the effect of different ellipsoid ratios of head profile changes on the overlap of fiber bundles is investigated.The larger the ellipsoid ratio of the prolate ellipsoid is,the smaller the overlap of gaps generated by neighboring fiber bundles is,and the overlap at the pole holes is also smaller,while the change of the oblate ellipsoid is not significant.The prolate ellipsoid has greater application and research value than the oblate ellipsoid in terms of processability,which is of great research significance for the design and fabrication of thermoplastic composite hydrogen storage cylinders for hydrogen-powered aircraft.展开更多
基金funded by the Seismic Situation Tracing Orientation Task,China Earthquake Administration(2014020120)the Science and Technology Support Program of Hebei Province(2014020120)
文摘We collected waveforms of a teleseismic event which occurred from January 2007 to October 2011 from 174 broadband seismic stations deployed in Hebei and its adjacent areas. Using the H-k stacking method,the average thickness and Poisson's ratio of the crust are acquired. In order to obtain reliable receiver functions, the broadband seismograms of 488 teleseismic earthquakes occurring in the epicentral distance range from 30° to 90° with magnitudes larger than Mb6. 0 are collected. The results show that crustal thickness have conspicuous lateral heterogeneity and have good correlation to the regional geological tectonic features. Poisson ratio's value is equated with the global models estimates which fluctuate at about 0. 25. Crustal thickness has positive correlation to the topography and the Taihang Mountains form the transition zone of thick and thin crustal thickness. There is an obvious difference in crustal thickness beneath the north and south of the Shanxi earthquake zone and the Poisson ratio of Datong,Ningwu and Anze basins is greater than 0. 3. The crustal thickness beneath the Zhang-Bo( Zhangjiakou-Bohai Sea)earthquake zone decreases from west to north and its Poisson ratio shows conspicuous lateral heterogeneity. The thin crust and low Poisson ratio in the Huabei( North China)basin may correlate with the delamination of the North China craton.
基金This work was supported by Special Funds of 2023 Jiangsu Provincial Science and Technology Plan(First Batch of Innovation Capacity Building Plan)[No.ZAG23009].
文摘Hydrogen-powered aircraft,as a cutting-edge exploration of clean-energy air transportation,impose more stringent requirements for lightweight hydrogen storage due to the limitations of aircraft weight and volume.Composite hydrogen storage cylinders have become one of the preferred solutions for hydrogen storage systems in hydrogen-powered aircraft due to their light weight and high strength.However,during the automated placement of high-stiffness thermoplastic composites(T700/PEEK),fibers may buckle or break in the head section.As the head radius decreases,the overlap of adjacent tows increases,resulting in an increase in the thickness of the polar pores,which is contrary to the light-weighting requirements.To solve this problem,this paper derives the trajectory algorithm as a manufacturing process limitation when thermoplastic fiber bundles are laid without wrinkles,provides a definition of the overlap rate between adjacent fibers,and the effect of different ellipsoid ratios of head profile changes on the overlap of fiber bundles is investigated.The larger the ellipsoid ratio of the prolate ellipsoid is,the smaller the overlap of gaps generated by neighboring fiber bundles is,and the overlap at the pole holes is also smaller,while the change of the oblate ellipsoid is not significant.The prolate ellipsoid has greater application and research value than the oblate ellipsoid in terms of processability,which is of great research significance for the design and fabrication of thermoplastic composite hydrogen storage cylinders for hydrogen-powered aircraft.
