The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is si...The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.展开更多
Magnesium cylindrical parts have relatively poor mechanical properties and distinct anisotropy of microstructure,which hinder their application as structural components.To improve the performance of WE71 cylindrical p...Magnesium cylindrical parts have relatively poor mechanical properties and distinct anisotropy of microstructure,which hinder their application as structural components.To improve the performance of WE71 cylindrical parts,multi-direction forging(MDF)was introduced before back extrusion,and the microstructure and mechanical properties were investigated.Results of microstructure show that the grain size in the outer of the cylindrical bottom is refined from 30.1 to 27.7μm,the micro structure is more uniform and the dislocation density is higher.The bimodal grain structure is formed in the outer of the cylindrical wall,which is ascribed to the formation of MgsRE phases along grain boundaries.These phases result in the Zener pinning effect on grain boundaries and the reduction of DRX volume fraction.The texture type of the cylindrical bottom is<0001>‖ED and the cylindrical wall is<1010>‖ED,and the maximum pole intensity is 1.986 and 1.664,respectively.Results of the tensile test at room temperature show that combined improved strength and ductility of the cylindrical part is attained after introducing the MDF process.The ultimate tensile strength(UTS),yield strength(YS)and elongation are279 MPa,185 MPa and 12%at the bottom and 299 MPa,212 MPa and 20%at the wall.展开更多
To predict the performance of multi-direction piezoelectric vibration energy harvester,an equation for calculating its output power is obtained based on elastic mechanics theory and piezoelectricity theory.Experiments...To predict the performance of multi-direction piezoelectric vibration energy harvester,an equation for calculating its output power is obtained based on elastic mechanics theory and piezoelectricity theory.Experiments are performed to verify theoretical analysis.When the excitation direction is along Y direction,a maximal output power about 0.139 mW can be harvested at a resistive load of 65kΩ and an excitation frequency of 136 Hz.Theoretical analysis agrees well with experimental results.Furthermore,the performance of multi-direction vibration energy harvester is experimentally tested.The results show that the multi-direction vibration energy harvester can harvest perfect energy as the excitation direction changes in XY plane,YZ plane,XZ plane and body diagonal plane of the harvester.展开更多
Image registration is an indispensable component in multi-source remote sensing image processing. In this paper, we put forward a remote sensing image registration method by including an improved multi-scale and multi...Image registration is an indispensable component in multi-source remote sensing image processing. In this paper, we put forward a remote sensing image registration method by including an improved multi-scale and multi-direction Harris algorithm and a novel compound feature. Multi-scale circle Gaussian combined invariant moments and multi-direction gray level co-occurrence matrix are extracted as features for image matching. The proposed algorithm is evaluated on numerous multi-source remote sensor images with noise and illumination changes. Extensive experimental studies prove that our proposed method is capable of receiving stable and even distribution of key points as well as obtaining robust and accurate correspondence matches. It is a promising scheme in multi-source remote sensing image registration.展开更多
In this paper,we propose a refined local learning scheme to reconstruct a high resolution(HR)face image from a low resolution(LR)observation.The contribution of this work is twofold.Firstly,multi-direction gradient fe...In this paper,we propose a refined local learning scheme to reconstruct a high resolution(HR)face image from a low resolution(LR)observation.The contribution of this work is twofold.Firstly,multi-direction gradient features are extracted to search the nearest neighbors for each image patch,then the non-negative matrix factorization(NMF)is used to reduce the complexity in weight calculation,and the initial HR embedding is estimated from the training pairs by preserving local geometry.Secondly,a global reconstruction constraint and post-processing by non-local filtering is incorporated into super-resolution(SR)reconstruction process to reduce the image artifacts and further improve the image visual quality.Experimental results show that the proposed algorithm improves the SR performance both in subjective and objective assessments compared with several existing methods.展开更多
The ocean,with its highly variable and complex meteorological conditions,harbors enormous renewable resources.Triboelectric nanogenerators(TENGs),which possess unique advantages,show exciting prospects in water wave e...The ocean,with its highly variable and complex meteorological conditions,harbors enormous renewable resources.Triboelectric nanogenerators(TENGs),which possess unique advantages,show exciting prospects in water wave energy collection.How to design and optimize TENGs to cover all characteristic water wave energies and achieve efficient energy utilization is emergent.In this paper,we carefully designed and fabricated a columnar multi-layer sliding TENG(CMLS-TENG)that can harvest water wave energy independent of wave height and direction.Drive rods with a hollow acrylic spherical shell were introduced to deliver wave energy,ensuring that the CMLS-TENG can work in all directions from 0°to 360°.Based on the sliding structure,switching the optimized CMLS-TENG is independent of wave heights.The optimized CMLS-TENG can achieve a total power density of 730 mW/m^(3) at a wave height of only 4.8 cm regardless of wave direction,which can illuminate multiple light-emitting diodes(LEDs)to provide lighting and provide power to a watch and a hygrometer for temperature and humidity monitoring.This work provides new choices and hopes for the effective collection of full-range water wave energy.展开更多
Purpose:The current study aimed to assess the protective performance of helmets equipped with multidirectional impact protection system(MIPS)under various oblique impact loads.Methods:Initially,a finite element model ...Purpose:The current study aimed to assess the protective performance of helmets equipped with multidirectional impact protection system(MIPS)under various oblique impact loads.Methods:Initially,a finite element model of a bicycle helmet with MIPS was developed based on thescanned geometric parameters of an actual bicycle helmet.Subsequently,the validity of model wasconfirmed using the KASK WG11 oblique impact test method.Three different impact angles(30°,45°,and 60°)and 2 varying impact speeds(5 m/s and 8 m/s)were employed in oblique tests to evaluateprotective performance of MIPS in helmets,focusing on injury assessment parameters such as peaklinear acceleration(PLA)and peak angular acceleration(PAA)of the head.Results:The results demonstrated that in all impact simulations,both assessment parameters werelower during impact for helmets equipped with MIPS compared to those without.The PAA wasconsistently lower in the MIPS helmet group,whereas the difference in PLA was not significant in the noMIPS helmet group.For instance,at an impact velocity of 8 m/s and a 30°inclined anvil,the MIPS helmetgroup exhibited a PAA of 3225 rad/s^(2) and a PLA of 281 g.In contrast,the no-MIPS helmet group displayeda PAA of 8243 rad/s^(2) and a PLA of 292 g.Generally,both PAA and PLA parameters decreased with theincrease of anvil angles.At a 60°anvil angles,PAA and PLA values were 664 rad/s^(2) and 20.7 g,respectively,reaching their minimum.Conclusion:The findings indicated that helmets incorporating MIPS offer enhanced protection againstvarious oblique impact loads.When assessing helmets for oblique impacts,the utilization of larger angleanvils and rear impacts might not adequately evaluate protective performance during an impact event.These findings will guide advancements in helmet design and the refinement of oblique impact testprotocols.展开更多
Many networks are designed to stack a large number of residual blocks,deepen the network and improve network performance through short residual connec-tion,long residual connection,and dense connection.However,without...Many networks are designed to stack a large number of residual blocks,deepen the network and improve network performance through short residual connec-tion,long residual connection,and dense connection.However,without consider-ing different contributions of different depth features to the network,these de-signs have the problem of evaluating the importance of different depth features.To solve this problem,this paper proposes an adaptive densely residual net-work(ADRNet)for the single image super resolution.ADRN realizes the evalua-tion of distributions of different depth features and learns more representative features.An adaptive densely residual block(ADRB)was designed,combining 3 residual blocks(RB)and dense connection was added.It learned the attention score of each dense connection through adaptive dense connections,and the at-tention score reflected the importance of the features of each RB.To further en-hance the performance of ADRB,a multi-direction attention block(MDAB)was introduced to obtain multidirectional context information.Through comparative experiments,it is proved that theproposed ADRNet is superior to the existing methods.Through ablation experiments,it is proved that evaluating features of different depths helps to improve network performance.展开更多
基金This study was jointly supported by the Science&Technology Fundamental Resources Investigation Program(2022FY101800)National Science Foundation(92162212)+1 种基金the project from the Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences,Wuhan)(TPR-2022-22)the International Geoscience Programme(IGCP-675)。
文摘The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.
基金Project supported by the General Program of National Natural Science Foundation of China(51871195,51501015)。
文摘Magnesium cylindrical parts have relatively poor mechanical properties and distinct anisotropy of microstructure,which hinder their application as structural components.To improve the performance of WE71 cylindrical parts,multi-direction forging(MDF)was introduced before back extrusion,and the microstructure and mechanical properties were investigated.Results of microstructure show that the grain size in the outer of the cylindrical bottom is refined from 30.1 to 27.7μm,the micro structure is more uniform and the dislocation density is higher.The bimodal grain structure is formed in the outer of the cylindrical wall,which is ascribed to the formation of MgsRE phases along grain boundaries.These phases result in the Zener pinning effect on grain boundaries and the reduction of DRX volume fraction.The texture type of the cylindrical bottom is<0001>‖ED and the cylindrical wall is<1010>‖ED,and the maximum pole intensity is 1.986 and 1.664,respectively.Results of the tensile test at room temperature show that combined improved strength and ductility of the cylindrical part is attained after introducing the MDF process.The ultimate tensile strength(UTS),yield strength(YS)and elongation are279 MPa,185 MPa and 12%at the bottom and 299 MPa,212 MPa and 20%at the wall.
基金Supported by the National Natural Science Foundation of China(51305183)the Qing Lan Project of Jiangsu Provincethe Doctoral Start-up Foundation of Jinling Institute of Technology(jit-b-201412)
文摘To predict the performance of multi-direction piezoelectric vibration energy harvester,an equation for calculating its output power is obtained based on elastic mechanics theory and piezoelectricity theory.Experiments are performed to verify theoretical analysis.When the excitation direction is along Y direction,a maximal output power about 0.139 mW can be harvested at a resistive load of 65kΩ and an excitation frequency of 136 Hz.Theoretical analysis agrees well with experimental results.Furthermore,the performance of multi-direction vibration energy harvester is experimentally tested.The results show that the multi-direction vibration energy harvester can harvest perfect energy as the excitation direction changes in XY plane,YZ plane,XZ plane and body diagonal plane of the harvester.
基金supported by National Nature Science Foundation of China (Nos. 61462046 and 61762052)Natural Science Foundation of Jiangxi Province (Nos. 20161BAB202049 and 20161BAB204172)+2 种基金the Bidding Project of the Key Laboratory of Watershed Ecology and Geographical Environment Monitoring, NASG (Nos. WE2016003, WE2016013 and WE2016015)the Science and Technology Research Projects of Jiangxi Province Education Department (Nos. GJJ160741, GJJ170632 and GJJ170633)the Art Planning Project of Jiangxi Province (Nos. YG2016250 and YG2017381)
文摘Image registration is an indispensable component in multi-source remote sensing image processing. In this paper, we put forward a remote sensing image registration method by including an improved multi-scale and multi-direction Harris algorithm and a novel compound feature. Multi-scale circle Gaussian combined invariant moments and multi-direction gray level co-occurrence matrix are extracted as features for image matching. The proposed algorithm is evaluated on numerous multi-source remote sensor images with noise and illumination changes. Extensive experimental studies prove that our proposed method is capable of receiving stable and even distribution of key points as well as obtaining robust and accurate correspondence matches. It is a promising scheme in multi-source remote sensing image registration.
基金the National Natural Science Foundation of China(Nos.61171165 and 60802039)the Natural Science Foundation of Jiangsu(No.BK2010488)+1 种基金the Qing Lan Project of Jiangsu Province"the Six Top Talents"of Jiangsu Province Grant(No.2012DZXX-36)
文摘In this paper,we propose a refined local learning scheme to reconstruct a high resolution(HR)face image from a low resolution(LR)observation.The contribution of this work is twofold.Firstly,multi-direction gradient features are extracted to search the nearest neighbors for each image patch,then the non-negative matrix factorization(NMF)is used to reduce the complexity in weight calculation,and the initial HR embedding is estimated from the training pairs by preserving local geometry.Secondly,a global reconstruction constraint and post-processing by non-local filtering is incorporated into super-resolution(SR)reconstruction process to reduce the image artifacts and further improve the image visual quality.Experimental results show that the proposed algorithm improves the SR performance both in subjective and objective assessments compared with several existing methods.
基金supported by the National Key R&D Project from Ministry of Science and Technology,China(No.2021YFA1201603)the National Natural Science Foundation of China(Nos.52073032 and 52192611)the Fundamental Research Funds for the Central Universities.
文摘The ocean,with its highly variable and complex meteorological conditions,harbors enormous renewable resources.Triboelectric nanogenerators(TENGs),which possess unique advantages,show exciting prospects in water wave energy collection.How to design and optimize TENGs to cover all characteristic water wave energies and achieve efficient energy utilization is emergent.In this paper,we carefully designed and fabricated a columnar multi-layer sliding TENG(CMLS-TENG)that can harvest water wave energy independent of wave height and direction.Drive rods with a hollow acrylic spherical shell were introduced to deliver wave energy,ensuring that the CMLS-TENG can work in all directions from 0°to 360°.Based on the sliding structure,switching the optimized CMLS-TENG is independent of wave heights.The optimized CMLS-TENG can achieve a total power density of 730 mW/m^(3) at a wave height of only 4.8 cm regardless of wave direction,which can illuminate multiple light-emitting diodes(LEDs)to provide lighting and provide power to a watch and a hygrometer for temperature and humidity monitoring.This work provides new choices and hopes for the effective collection of full-range water wave energy.
基金This work was supported by the Natural Science FoundationProject of Xiamen City,China(3502Z20227223)Fujian Provincial Technological Innovation Key Research and IndustryDevelopment Project(2022G43)and(2023G048).
文摘Purpose:The current study aimed to assess the protective performance of helmets equipped with multidirectional impact protection system(MIPS)under various oblique impact loads.Methods:Initially,a finite element model of a bicycle helmet with MIPS was developed based on thescanned geometric parameters of an actual bicycle helmet.Subsequently,the validity of model wasconfirmed using the KASK WG11 oblique impact test method.Three different impact angles(30°,45°,and 60°)and 2 varying impact speeds(5 m/s and 8 m/s)were employed in oblique tests to evaluateprotective performance of MIPS in helmets,focusing on injury assessment parameters such as peaklinear acceleration(PLA)and peak angular acceleration(PAA)of the head.Results:The results demonstrated that in all impact simulations,both assessment parameters werelower during impact for helmets equipped with MIPS compared to those without.The PAA wasconsistently lower in the MIPS helmet group,whereas the difference in PLA was not significant in the noMIPS helmet group.For instance,at an impact velocity of 8 m/s and a 30°inclined anvil,the MIPS helmetgroup exhibited a PAA of 3225 rad/s^(2) and a PLA of 281 g.In contrast,the no-MIPS helmet group displayeda PAA of 8243 rad/s^(2) and a PLA of 292 g.Generally,both PAA and PLA parameters decreased with theincrease of anvil angles.At a 60°anvil angles,PAA and PLA values were 664 rad/s^(2) and 20.7 g,respectively,reaching their minimum.Conclusion:The findings indicated that helmets incorporating MIPS offer enhanced protection againstvarious oblique impact loads.When assessing helmets for oblique impacts,the utilization of larger angleanvils and rear impacts might not adequately evaluate protective performance during an impact event.These findings will guide advancements in helmet design and the refinement of oblique impact testprotocols.
文摘Many networks are designed to stack a large number of residual blocks,deepen the network and improve network performance through short residual connec-tion,long residual connection,and dense connection.However,without consider-ing different contributions of different depth features to the network,these de-signs have the problem of evaluating the importance of different depth features.To solve this problem,this paper proposes an adaptive densely residual net-work(ADRNet)for the single image super resolution.ADRN realizes the evalua-tion of distributions of different depth features and learns more representative features.An adaptive densely residual block(ADRB)was designed,combining 3 residual blocks(RB)and dense connection was added.It learned the attention score of each dense connection through adaptive dense connections,and the at-tention score reflected the importance of the features of each RB.To further en-hance the performance of ADRB,a multi-direction attention block(MDAB)was introduced to obtain multidirectional context information.Through comparative experiments,it is proved that theproposed ADRNet is superior to the existing methods.Through ablation experiments,it is proved that evaluating features of different depths helps to improve network performance.
