In this paper, the isogeometric analysis (IGA) is employed to develop an acoustic radiation model for a double plate-acoustic cavity coupling system, with a focus on analyzing the sound transmission loss (STL). The fu...In this paper, the isogeometric analysis (IGA) is employed to develop an acoustic radiation model for a double plate-acoustic cavity coupling system, with a focus on analyzing the sound transmission loss (STL). The functionally graded (FG) plate exhibits a different material properties in-plane, and the power-law rule is adopted as the governing principle for material mixing. To validate the harmonic response and demonstrate the accuracy and convergence of the isogeometric modeling, ANASYS is utilized to compare with numerical examples. A plane wave serves as the acoustic excitation, and the Rayleigh integral is applied to discretize the radiated plate. The STL results are compared with the literature, confirming the reliability of the coupling system. Finally, the investigation is conducted to study impact of cavity depth and power-law parameter on the STL.展开更多
Ultrasonic-stationary shoulder assisted friction stir welding(U-SSFSW)is a novel hybrid welding technique,which reveals promising prospect in joining Al/Mg dissimilar alloys.A thorough understanding of U-SSFSW process...Ultrasonic-stationary shoulder assisted friction stir welding(U-SSFSW)is a novel hybrid welding technique,which reveals promising prospect in joining Al/Mg dissimilar alloys.A thorough understanding of U-SSFSW process is imperative for the further application of this technique.Pigeon-inspired optimization(PIO)is a swarm intelligent optimization algorithm and is proposed in mathematical modeling and process optimization by artificial intelligence.In this study,PIO optimized artificial neural network(PIOANN)was firstly established to acquire the relationships between the inputs and output of the Al/Mg welding process by U-SSFSW technique.A reliable PIO-ANN was achieved and the joint with a tensile strength of 161 MPa was acquired under the PIO optimized parameters.This tensile strength is higher than any ever-reported results with the similar welding condition.The joint formation,microstructure,microhardness and fracture behaviors were systemically investigated based on the reported studies and the confirmation experiment of this study to explore the enhancing mechanism of U-SSFSW Al/Mg joint.展开更多
A series of parallel normal faults are distributed in the Helan Mountain-Yinchuan Basin tectonic belt,where a historical M8.0 earthquake occurred.It is rare that such a great earthquake occurs in a normal fault system...A series of parallel normal faults are distributed in the Helan Mountain-Yinchuan Basin tectonic belt,where a historical M8.0 earthquake occurred.It is rare that such a great earthquake occurs in a normal fault system within the continent.To deeply understand the fine structure of the normal fault system,we deployed 104 broadband temporary stations near the system,collected data from permanent stations and other temporary stations nearby,and obtained the high-precision threedimensional S-wave velocity structure beneath 206 stations via joint inversion of receiver function and surface wave.A typical graben-in-graben feature bounded by four major faults was identified in the Yinchuan Basin.We analyzed the seismicity in the normal fault system and found a seismic strip in the southern part of the basin,where there are significant changes in the sedimentary thickness,which is speculated to be the southern boundary of the normal fault system.There are significant differences in the crustal thickness and velocity structure in the crust on both sides of the boundary between the Helan Mountain and the Yinchuan Basin,and a low-velocity zone was identified in the upper mantle beneath this boundary,which could be related to the fact that the Helan Mountain-Yinchuan Basin tectonic belt is located between the Alxa Block and the Ordos Block.The M8.0 Yinchuan-Pingluo earthquake occurred at the junction of four major faults in the Yinchuan Basin,which was located in the high-velocity zone near the velocity transition zone at the basin-mountain boundary.The low-velocity zone in the upper mantle beneath this boundary may have promoted the nucleation of this earthquake.Based on evidence from geological drilling,micro seismicity,the regional stress field,and the velocity models obtained in this study,it is inferred that the eastern piedmont fault zone of the Helan Mountain was the seismogenic fault of the 1739 M8.0 Yinchuan-Pingluo earthquake.展开更多
This paper investigated the nanostructure and oxidation reactivity of soot generated from biofuel 2,5-dimethylfuran pyrolysis with different CO_(2) additions and different temperatures in a quartz tube flow reactor.Th...This paper investigated the nanostructure and oxidation reactivity of soot generated from biofuel 2,5-dimethylfuran pyrolysis with different CO_(2) additions and different temperatures in a quartz tube flow reactor.The morphology and nanostructure of soot samples were characterized by a low and a high resolution transmission electron spectroscopy(TEM and HRTEM)and an X-ray diffraction(XRD).The oxidation reactivity of these samples was explored by a thermogravimetric analyzer(TGA).Different soot samples were collected in the tail of the tube.With the increase of temperature,the soot showed a smaller mean particle diameter,a longer fringe length,and a lower fringe tortuosity,as well as a higher degree of graphization.However,the variation of soot nanostructures resulting from different CO_(2) additions was not linear.Compared with 0%,50%,and 100%CO_(2) additions at one fixed temperature,the soot collected from the 10%CO_(2) addition has the highest degree of graphization and crystallization.At three temperatures of 1173 K,1223 K,and 1273 K,the mean values of fringe length distribution displayed a ranking of 10%CO_(2)>100%CO_(2)>50%CO_(2) while the mean particle diameters showed the same order.Furthermore,the oxidation reactivity of different soot samples decreased in the ranking of 50%CO_(2) addition>100%CO_(2) addition>10%CO_(2) addition,which was equal to the ranking of mean values of fringe tortuosity distribution.The result further confirmed the close relationship between soot nanostructure and oxidation reactivity.展开更多
文摘In this paper, the isogeometric analysis (IGA) is employed to develop an acoustic radiation model for a double plate-acoustic cavity coupling system, with a focus on analyzing the sound transmission loss (STL). The functionally graded (FG) plate exhibits a different material properties in-plane, and the power-law rule is adopted as the governing principle for material mixing. To validate the harmonic response and demonstrate the accuracy and convergence of the isogeometric modeling, ANASYS is utilized to compare with numerical examples. A plane wave serves as the acoustic excitation, and the Rayleigh integral is applied to discretize the radiated plate. The STL results are compared with the literature, confirming the reliability of the coupling system. Finally, the investigation is conducted to study impact of cavity depth and power-law parameter on the STL.
基金supported by the National Natural Science Foundation of China(No.51874201)the Science Technology Major Project of Liaoning Province,China(No.2019JH1/10100028)。
文摘Ultrasonic-stationary shoulder assisted friction stir welding(U-SSFSW)is a novel hybrid welding technique,which reveals promising prospect in joining Al/Mg dissimilar alloys.A thorough understanding of U-SSFSW process is imperative for the further application of this technique.Pigeon-inspired optimization(PIO)is a swarm intelligent optimization algorithm and is proposed in mathematical modeling and process optimization by artificial intelligence.In this study,PIO optimized artificial neural network(PIOANN)was firstly established to acquire the relationships between the inputs and output of the Al/Mg welding process by U-SSFSW technique.A reliable PIO-ANN was achieved and the joint with a tensile strength of 161 MPa was acquired under the PIO optimized parameters.This tensile strength is higher than any ever-reported results with the similar welding condition.The joint formation,microstructure,microhardness and fracture behaviors were systemically investigated based on the reported studies and the confirmation experiment of this study to explore the enhancing mechanism of U-SSFSW Al/Mg joint.
基金China University of Geosciences(Beijing)and the National Key R&D Program Key technologies and application of 3D modeling of active faults for three different structural types(Grant No.2018YFC1504100)for providing the 3D fault data of the normal fault system in the Yinchuan Basinsupported by the Special Fund of the Institute of Geophysics,China Earthquake Administration(Grant No.DQJB19A35)+1 种基金the National Natural Science Foundation of China(Grant No.41974058)the National Key R&D Program(Grant No.2018YFC1504103)。
文摘A series of parallel normal faults are distributed in the Helan Mountain-Yinchuan Basin tectonic belt,where a historical M8.0 earthquake occurred.It is rare that such a great earthquake occurs in a normal fault system within the continent.To deeply understand the fine structure of the normal fault system,we deployed 104 broadband temporary stations near the system,collected data from permanent stations and other temporary stations nearby,and obtained the high-precision threedimensional S-wave velocity structure beneath 206 stations via joint inversion of receiver function and surface wave.A typical graben-in-graben feature bounded by four major faults was identified in the Yinchuan Basin.We analyzed the seismicity in the normal fault system and found a seismic strip in the southern part of the basin,where there are significant changes in the sedimentary thickness,which is speculated to be the southern boundary of the normal fault system.There are significant differences in the crustal thickness and velocity structure in the crust on both sides of the boundary between the Helan Mountain and the Yinchuan Basin,and a low-velocity zone was identified in the upper mantle beneath this boundary,which could be related to the fact that the Helan Mountain-Yinchuan Basin tectonic belt is located between the Alxa Block and the Ordos Block.The M8.0 Yinchuan-Pingluo earthquake occurred at the junction of four major faults in the Yinchuan Basin,which was located in the high-velocity zone near the velocity transition zone at the basin-mountain boundary.The low-velocity zone in the upper mantle beneath this boundary may have promoted the nucleation of this earthquake.Based on evidence from geological drilling,micro seismicity,the regional stress field,and the velocity models obtained in this study,it is inferred that the eastern piedmont fault zone of the Helan Mountain was the seismogenic fault of the 1739 M8.0 Yinchuan-Pingluo earthquake.
基金supported by the National Natural Science Foundation of China(Grant Nos.51822605 and 51576100)333 Program of Jiangsu Province(No.BRA2017428).
文摘This paper investigated the nanostructure and oxidation reactivity of soot generated from biofuel 2,5-dimethylfuran pyrolysis with different CO_(2) additions and different temperatures in a quartz tube flow reactor.The morphology and nanostructure of soot samples were characterized by a low and a high resolution transmission electron spectroscopy(TEM and HRTEM)and an X-ray diffraction(XRD).The oxidation reactivity of these samples was explored by a thermogravimetric analyzer(TGA).Different soot samples were collected in the tail of the tube.With the increase of temperature,the soot showed a smaller mean particle diameter,a longer fringe length,and a lower fringe tortuosity,as well as a higher degree of graphization.However,the variation of soot nanostructures resulting from different CO_(2) additions was not linear.Compared with 0%,50%,and 100%CO_(2) additions at one fixed temperature,the soot collected from the 10%CO_(2) addition has the highest degree of graphization and crystallization.At three temperatures of 1173 K,1223 K,and 1273 K,the mean values of fringe length distribution displayed a ranking of 10%CO_(2)>100%CO_(2)>50%CO_(2) while the mean particle diameters showed the same order.Furthermore,the oxidation reactivity of different soot samples decreased in the ranking of 50%CO_(2) addition>100%CO_(2) addition>10%CO_(2) addition,which was equal to the ranking of mean values of fringe tortuosity distribution.The result further confirmed the close relationship between soot nanostructure and oxidation reactivity.
