3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situa...3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situations. This paper summarizes the general concept of geological modeling; compares the characteristics of borehole-based modeling, cross-section based modeling and multi- source interactive modeling; analyses key techniques in 3-D geological modeling; and highlights the main difficulties and directions of future studies.展开更多
Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D g...Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology (3-D GMT), this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT: building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.展开更多
A 3-D numerical model is set up in a large domain covering the Hangzhou Bay and the Changjiang Estuary based on the ECOM model in orthogonal curvilinear coordinates.The numerical schemes for baroclinic pressure gradie...A 3-D numerical model is set up in a large domain covering the Hangzhou Bay and the Changjiang Estuary based on the ECOM model in orthogonal curvilinear coordinates.The numerical schemes for baroclinic pressure gradient (BPG)terms and convective terms are improved in the paper according to the characteristics of velocity field and mass transport in the area.The model is validated by the simulations of residual current and salinity transport in the Hangzhou Bay and the Changjiang Estuary.展开更多
3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasin...3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasing personalization demand and still guarantee aesthetics.This paper proposes amethod to construct 3-D human models by applying deep learning.We calculate the location of the main slices of the human body,including the neck,chest,belly,buttocks,and the rings of the extremities,using pre-existing information.Then,on the positioning frame,we find the key points(fixed and unaltered)of these key slices and update these points tomatch the current parameters.To add points to a star slice,we use a deep learning model tomimic the form of the human body at that slice position.We use interpolation to produce sub-slices of different body sections based on the main slices to create complete body parts morphologically.We combine all slices to construct a full 3-D representation of the human body.展开更多
Effectively and accurately modelling the spatial relation of fracture surfaces is crucial in the design and construction of large hydropower dams having a complex underlying geology. However, fracture surfaces are ran...Effectively and accurately modelling the spatial relation of fracture surfaces is crucial in the design and construction of large hydropower dams having a complex underlying geology. However, fracture surfaces are randomly formed and vary greatly with respect to their spatial distribution, which makes the construction of accurate 3-D models challenging. In this study, we use an optimal Monte Carlo simulation and dynamic conditioning to construct a fracture network model. We found the optimal Monte Carlo simulation to effectively reduce the error associated with the Monte Carlo method and use dynamic conditioning to ensure the consistency of the model with the actual distribution of fractures on the excavation faces and outcrops. We applied this novel approach to a hydropower station on the Jinshajiang River, China. The simulation results matched the real sampled values well, confirming that the model is capable of effectively and accurately simulating the spatial relations in a fracture network.展开更多
Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 1...Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 19 failed and other pillars failed progressively as a domino effect and 4000 m2 of mine collapsed within a few minutes, consequently. For detail investigation, two 3-D numerical models were developed by 3Dec. The first, a base model, was used for estimation of stress on pillars just before failure and the other for investigation of rock burst in pillar No. 19. The results show that discontinuity parameters such as friction angle and shear stiffness is critical parameters in this pillar failure. In addition, it indicates that W/H ratio equal 0.3, the lack of ore extraction strategy and inadequate roof support are the major reasons for this failure. In this paper, the procedure of study was described.展开更多
In meandering rivers, the flow pattern is highly complex, with specific characteristics at bends that are not observed along straight paths. A numerical model can be effectively used to predict such flow fields. Since...In meandering rivers, the flow pattern is highly complex, with specific characteristics at bends that are not observed along straight paths. A numerical model can be effectively used to predict such flow fields. Since river bends are not uniform-some are divergent and others convergent-in this study, after the SSIIM 3-D model was calibrated using the result of measurements along a uniform 180° bend with a width of 0.6 m, a similar but convergent 180v bend, 0.6 m to 0.45 m wide, was simulated using the SSI1M 3-D numerical model. Flow characteristics of the convergent 180° bend, including lengthwise and vertical velocity profiles, primary and secondary flows, lengthwise and widtbwise slopes of the water surface, and the helical flow strength, were compared with those of the uniform 180° bend. The verification results of the model show that the numerical model can effectively simulate the flow field in the uniform bend. In addition, this research indicates that, in a convergent channel, the maximum velocity path at a plane near the water surface crosses the channel's centerline at about a 30° to 40° cross-section, while in the uniform bend, this occurs at about the 50° cross-section. The varying range of the water surface elevation is wider in the convergent channel than in the uniform one, and the strength of the helical flow is generally greater in the uniform channel than in the convergent one. Also, unlike the uniform bend, the convergent bend exhibits no rotational cell against the main direction of secondary flow rotation at the 135° cross-section.展开更多
The San Rafael Block(SRB)is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza,Argentina.This block is located in the Andean foothills between the orogenic front and foreland base...The San Rafael Block(SRB)is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza,Argentina.This block is located in the Andean foothills between the orogenic front and foreland basement uplifts of late Miocene age.In order to analyze the geochronological evolution of the Quaternary volcanism in the region,several geologic and geophysical studies have been conducted.Nevertheless,the crust,where the SRB is located,has not been well characterized yet.Based on gravimetric and magnetic data,together with isostatic and elastic thickness analyses,we modeled the crustal structure of the area.Information obtained has allowed us to understand the crust where the SRB and the Payenia volcanic province are located.Bouguer anomalies indicate that the SRB presents higher densities to the North of Cerro Nevado and Moho calculations suggest depths for this block between 40 and 50 km.Determinations of elastic thickness would indicate that the crust supporting the San Rafael Block presents values of approximately 10 km,being enough to support the block loading.However,in the Payenia region,elastic thickness values are close to zero due to the regional temperature increase.展开更多
This paper describes a method of the computer aided garment design,and discusses 3-D humanbody,wire frame modelling,approaches of expressing and a shading model of the 3-D garment.
Three-dimensional(3-D)Markov cubic random mesh models are presented andproved in the form of two theorems in details.Its applications to the modeling and description of3-D images are described.The model presented here...Three-dimensional(3-D)Markov cubic random mesh models are presented andproved in the form of two theorems in details.Its applications to the modeling and description of3-D images are described.The model presented here is a appropriate mathematical tool for thesegmentation,modeling,classification and other processing.Finally,an example is given.展开更多
Seismic hazard assessment based on urban active faults can provide scientific bases for city planning and project construction, while numerical simulation of strong ground motion is an important method for seismic haz...Seismic hazard assessment based on urban active faults can provide scientific bases for city planning and project construction, while numerical simulation of strong ground motion is an important method for seismic hazard prediction and assessment. A 3-D physical model in conformity with real strata configuration of (mainly) the Quaternary is a prerequisite to ensure the reliability of the simulation results. In this paper, we give a detailed account of the technical scheme and process for creating a 3-D physical model in Kunming basin. The data used are synthe- sized from seismogeological data, borehole data, topographic data, digital elevation mode (DEM) data, seismic exploration results and wave velocity measurements. Strafigraphic division is based mainly on shear wave velocity, with strata sequence taken into consideration. The model construction is finally accomplished with ArcGIS and many relevant programming techniques via layer-by-layer stacking (in depth direction) of the adjacent medium interfaces (meshes). Meanwhile, a database of 3-D physical models is set up, which provides model data and parameters for strong ground motion simulation. Some processing methods and significant issues are also addressed in the paper in accordance with different types of exploration and experimental data.展开更多
Automatic target recognition (ATR) is an important issue for military applications, the topic of the ATR system belongs to the field of pattern recognition and classification. In the paper, we present an approach fo...Automatic target recognition (ATR) is an important issue for military applications, the topic of the ATR system belongs to the field of pattern recognition and classification. In the paper, we present an approach for building an ATR system with improved artificial neural network to recog- nize and classify the typical targets in the battle field. The invariant features of Hu invariant moments and roundness were selected to be the inputs of the neural network because they have the invari- ances of rotation, translation and scaling. The pictures of the targets are generated by the 3-D mod- els to improve the recognition rate because it is necessary to provide enough pictures for training the artificial neural network. The simulations prove that the approach can be implement ed in the ATR system and it has a high recognition rate and can be applied in real time.展开更多
Based on the statistical model for the tensile statistical strength of unidirectional composite materials and the stress analysis of 3-D braided composites, a new method is proposed to calculate the tensile statistica...Based on the statistical model for the tensile statistical strength of unidirectional composite materials and the stress analysis of 3-D braided composites, a new method is proposed to calculate the tensile statistical strength of the 3-D braided compos- ites. With this method, the strength of 3-D braided composites can be calculated with very large accuracy, and the statistical parameters of 3-D braided composites can be determined. The numerical result shows that the tensile statistical strength of 3-D braided composites can be predicted using this method.展开更多
Introduction Cancer is an attractive target of gene therapy and currently represents the disease in most clinical trials[1]. Strategies for cancer gene therapy include: (1) stimulation of immune responses to tumor cel...Introduction Cancer is an attractive target of gene therapy and currently represents the disease in most clinical trials[1]. Strategies for cancer gene therapy include: (1) stimulation of immune responses to tumor cells,(2) delivery of specific enzymes展开更多
Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The...Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The model was validated using the data collected before the opening of the bridge to the public. The bridge was instrumented to conduct fullscale static and dynamic tests. The static tests were to measure the deflection of the bridge pier while the dynamic tests to measure the free vibrations of the pier due to a sudden release of the static load. Confederation Bridge is one of the longest reinforced concrete bridges in the world. It connects the province of Prince Edward Island and the province of New Brunswick in Canada. Due to its strategic location and vital role as a transportation link between these two provinces, it was designed using higher safety factors than those for typical highway bridges. After validating the present numerical model, a procedure was developed to evaluate the performance of similar bridges subjected to traffic and seismic loads. It is of interest to note that the foundation stiffness and the modulus of elasticity of the concrete have significant effects on the structural responses of the Confederation Bridge.展开更多
Various models exist to explain the formation of the Tibetan Plateau,including“tectonic escape”,“pure shear thickening”,“convective removal of the lithospheric mantle”,and“lower crustal flow”model.The first tw...Various models exist to explain the formation of the Tibetan Plateau,including“tectonic escape”,“pure shear thickening”,“convective removal of the lithospheric mantle”,and“lower crustal flow”model.The first two models are primarily constructed on pure mechanical models but are unable to reasonably explain the tension and shear phenomena inside the plateau.The latter two are rheological dynamic models based on deep geophysical observations.However,the spatial range of the lower crustal flow and its role in the plateau formation/uplift remain controversial.Five multi-terrane viscoplastic thermomechanical models were constructed to simulate the uplift and lithospheric structure change of the Tibetan Plateau during the post-collision stage(since 35 Ma)under the convergence of the Indian Plate.Results show that the plateau's formation begins with crustal thickening,blocked by strong terranes at the northern plateau,and expanded laterally to the east.The lithosphere thickens gradually and experiences delamination at its base,elevating temperature within the crust and forming partial melting layers in the central plateau.As convergence persists on the southern side,the northern plateau's lithosphere bends downward and undergoes delamination,further heating the crust and promoting the northward and eastward flow of partial melting layers,leading to secondary uplift around the plateau.展开更多
The pneumatic muscle actuator(PMA)has many advantages,such as good flexibility,high power/weight ratio,but its nonlinearity makes it difficult to build a static mathematical model with high precision.A new method is p...The pneumatic muscle actuator(PMA)has many advantages,such as good flexibility,high power/weight ratio,but its nonlinearity makes it difficult to build a static mathematical model with high precision.A new method is proposed to establish the model of PMA.The concept of hybrid elastic modulus which is related to the static characteristic of PMA is put forward,and the energy conservation law is used to achieve the expression of the hybrid elastic modulus,which can be fitted out based on experimental data,and the model of PMA can be derived from this expression.At the same time,a 3-DOF parallel mechanism(a new bionic shoulder joint)driven by five PMAs is designed.This bionic shoulder joint adopts the structure of two antagonistic PMAs actualizing a rotation control and three PMAs controlling another two rotations to get better rotation characteristics.The kinematic and dynamic characteristics of the mechanism are analyzed and a new static model of PMA is used to control it.Experimental results demonstrate the effectiveness of this new static model.展开更多
In order to accurately simulate strong three-dimensional (3-D) free surface flows and sediment transport, the fully 3- D non-hydrostatic pressure models are developed based on the incompressible Navier-Stokes equati...In order to accurately simulate strong three-dimensional (3-D) free surface flows and sediment transport, the fully 3- D non-hydrostatic pressure models are developed based on the incompressible Navier-Stokes equations and convection-diffusion equation of sediment concentration with the mixing triangle and quadrilateral grids. The governing equations are discretized with the unstructured finite volume method in order to provide conservation properties of mass and momentum, and flexibility with practical application. It is shown that it is first-order accurate on nonuniform plane two-dimensional (2-D) grids and second-order accurate on uniform plane grids. A third-order approximation of the vertical velocity at the top-layer is applied. In such a way, free surface zero stress boundary condition is satisfied maturely, and very few vertical layers are needed to give an accurate solution even for complex discontinuous flow and short wave simulation. The model is applied to four examples to simulate strong 3-D free surface flows and sediment transport where non-hydrostatic pressures have a considerable effect on the velocity field. The newly developed model is verified against analytical solutions with an excellent agreement.展开更多
The 3-D seismic dataset is a key tool to analyze and understand the mechanism of structural and stratigraphic hydrocarbon(HC)trapping in the subsurface.Conventionally used subsurface seismic characterization methods f...The 3-D seismic dataset is a key tool to analyze and understand the mechanism of structural and stratigraphic hydrocarbon(HC)trapping in the subsurface.Conventionally used subsurface seismic characterization methods for fractures are based on the theory of effective anisotropy medium.The aim of this work is to improve the structural images with dense sampling of 3-D survey to evaluate structural and stratigraphic models for reservoir development to predict reservoir quality.The present study of the Gullfaks Field,located in the Norwegian North Sea Gullfaks sector,identifies the shallowest structural elements.The steepness of westward structural dip decreases eastward during the Upper Jurassic to Lower Cretaceous deposition.Reservoir sands consist of the Middle Jurassic deltaic deposits and Lower Jurassic fluvial channel and delta plain deposits.Sediment supply steadily prevails on sea-level rise and the succession displays a regressive trend indicated by a good continuous stacking pattern.The key factor for the development of reservoirs in the Gullfaks Field is fault transmissibility with spatially distributed pressure.The majority of mapped faults with sand-to-sand contacts are non-sealing,which provide restriction for the HC flow between the fault blocks.The traps for HC accumulation occur between the post-rift and syn-rift strata,i.e.antiform set by extensional system,unconformity trap at the top of syndeposition,and structural trap due to normal faults.Overall reservoir quality in the studied area is generally excellent with average 35%porosity and permeability in the Darcy range.Our findings are useful to better understand the development of siliciclastic reservoirs in similar geological settings worldwide.展开更多
文摘3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situations. This paper summarizes the general concept of geological modeling; compares the characteristics of borehole-based modeling, cross-section based modeling and multi- source interactive modeling; analyses key techniques in 3-D geological modeling; and highlights the main difficulties and directions of future studies.
文摘Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology (3-D GMT), this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT: building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.
文摘A 3-D numerical model is set up in a large domain covering the Hangzhou Bay and the Changjiang Estuary based on the ECOM model in orthogonal curvilinear coordinates.The numerical schemes for baroclinic pressure gradient (BPG)terms and convective terms are improved in the paper according to the characteristics of velocity field and mass transport in the area.The model is validated by the simulations of residual current and salinity transport in the Hangzhou Bay and the Changjiang Estuary.
基金Funding for this study from Sai Gon University(Grant No.CSA2021–08).
文摘3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasing personalization demand and still guarantee aesthetics.This paper proposes amethod to construct 3-D human models by applying deep learning.We calculate the location of the main slices of the human body,including the neck,chest,belly,buttocks,and the rings of the extremities,using pre-existing information.Then,on the positioning frame,we find the key points(fixed and unaltered)of these key slices and update these points tomatch the current parameters.To add points to a star slice,we use a deep learning model tomimic the form of the human body at that slice position.We use interpolation to produce sub-slices of different body sections based on the main slices to create complete body parts morphologically.We combine all slices to construct a full 3-D representation of the human body.
基金supported by the National Basic Research Program of China (973 Program, No. 2013CB035904)the Innovative Research Groups of the National Natural Science Foundation of China (No. 51321065)the National Natural Science Foundation of China (No. 51439005)
文摘Effectively and accurately modelling the spatial relation of fracture surfaces is crucial in the design and construction of large hydropower dams having a complex underlying geology. However, fracture surfaces are randomly formed and vary greatly with respect to their spatial distribution, which makes the construction of accurate 3-D models challenging. In this study, we use an optimal Monte Carlo simulation and dynamic conditioning to construct a fracture network model. We found the optimal Monte Carlo simulation to effectively reduce the error associated with the Monte Carlo method and use dynamic conditioning to ensure the consistency of the model with the actual distribution of fractures on the excavation faces and outcrops. We applied this novel approach to a hydropower station on the Jinshajiang River, China. The simulation results matched the real sampled values well, confirming that the model is capable of effectively and accurately simulating the spatial relations in a fracture network.
文摘Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving works such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 19 failed and other pillars failed progressively as a domino effect and 4000 m2 of mine collapsed within a few minutes, consequently. For detail investigation, two 3-D numerical models were developed by 3Dec. The first, a base model, was used for estimation of stress on pillars just before failure and the other for investigation of rock burst in pillar No. 19. The results show that discontinuity parameters such as friction angle and shear stiffness is critical parameters in this pillar failure. In addition, it indicates that W/H ratio equal 0.3, the lack of ore extraction strategy and inadequate roof support are the major reasons for this failure. In this paper, the procedure of study was described.
文摘In meandering rivers, the flow pattern is highly complex, with specific characteristics at bends that are not observed along straight paths. A numerical model can be effectively used to predict such flow fields. Since river bends are not uniform-some are divergent and others convergent-in this study, after the SSIIM 3-D model was calibrated using the result of measurements along a uniform 180° bend with a width of 0.6 m, a similar but convergent 180v bend, 0.6 m to 0.45 m wide, was simulated using the SSI1M 3-D numerical model. Flow characteristics of the convergent 180° bend, including lengthwise and vertical velocity profiles, primary and secondary flows, lengthwise and widtbwise slopes of the water surface, and the helical flow strength, were compared with those of the uniform 180° bend. The verification results of the model show that the numerical model can effectively simulate the flow field in the uniform bend. In addition, this research indicates that, in a convergent channel, the maximum velocity path at a plane near the water surface crosses the channel's centerline at about a 30° to 40° cross-section, while in the uniform bend, this occurs at about the 50° cross-section. The varying range of the water surface elevation is wider in the convergent channel than in the uniform one, and the strength of the helical flow is generally greater in the uniform channel than in the convergent one. Also, unlike the uniform bend, the convergent bend exhibits no rotational cell against the main direction of secondary flow rotation at the 135° cross-section.
文摘The San Rafael Block(SRB)is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza,Argentina.This block is located in the Andean foothills between the orogenic front and foreland basement uplifts of late Miocene age.In order to analyze the geochronological evolution of the Quaternary volcanism in the region,several geologic and geophysical studies have been conducted.Nevertheless,the crust,where the SRB is located,has not been well characterized yet.Based on gravimetric and magnetic data,together with isostatic and elastic thickness analyses,we modeled the crustal structure of the area.Information obtained has allowed us to understand the crust where the SRB and the Payenia volcanic province are located.Bouguer anomalies indicate that the SRB presents higher densities to the North of Cerro Nevado and Moho calculations suggest depths for this block between 40 and 50 km.Determinations of elastic thickness would indicate that the crust supporting the San Rafael Block presents values of approximately 10 km,being enough to support the block loading.However,in the Payenia region,elastic thickness values are close to zero due to the regional temperature increase.
文摘This paper describes a method of the computer aided garment design,and discusses 3-D humanbody,wire frame modelling,approaches of expressing and a shading model of the 3-D garment.
文摘Three-dimensional(3-D)Markov cubic random mesh models are presented andproved in the form of two theorems in details.Its applications to the modeling and description of3-D images are described.The model presented here is a appropriate mathematical tool for thesegmentation,modeling,classification and other processing.Finally,an example is given.
基金Urban Active Fault Detection Project sponsored by the National Development andReform Commission of China(2004-1138)National Natural Science Foundation of China(40604005)+1 种基金Joint Seismological Science Foundation of China(A07027)Key Project during the 10th Five-year Plan Period from Earthquake Administration of China(J105B-16).
文摘Seismic hazard assessment based on urban active faults can provide scientific bases for city planning and project construction, while numerical simulation of strong ground motion is an important method for seismic hazard prediction and assessment. A 3-D physical model in conformity with real strata configuration of (mainly) the Quaternary is a prerequisite to ensure the reliability of the simulation results. In this paper, we give a detailed account of the technical scheme and process for creating a 3-D physical model in Kunming basin. The data used are synthe- sized from seismogeological data, borehole data, topographic data, digital elevation mode (DEM) data, seismic exploration results and wave velocity measurements. Strafigraphic division is based mainly on shear wave velocity, with strata sequence taken into consideration. The model construction is finally accomplished with ArcGIS and many relevant programming techniques via layer-by-layer stacking (in depth direction) of the adjacent medium interfaces (meshes). Meanwhile, a database of 3-D physical models is set up, which provides model data and parameters for strong ground motion simulation. Some processing methods and significant issues are also addressed in the paper in accordance with different types of exploration and experimental data.
基金Supported by the Ministerial Level Advanced Research Foundation(9140A01010411BQ01)the National Twelfth Five-Year Project(40405050303)
文摘Automatic target recognition (ATR) is an important issue for military applications, the topic of the ATR system belongs to the field of pattern recognition and classification. In the paper, we present an approach for building an ATR system with improved artificial neural network to recog- nize and classify the typical targets in the battle field. The invariant features of Hu invariant moments and roundness were selected to be the inputs of the neural network because they have the invari- ances of rotation, translation and scaling. The pictures of the targets are generated by the 3-D mod- els to improve the recognition rate because it is necessary to provide enough pictures for training the artificial neural network. The simulations prove that the approach can be implement ed in the ATR system and it has a high recognition rate and can be applied in real time.
基金Supported by the National Natural Science Foundation of China(51075031)
文摘Based on the statistical model for the tensile statistical strength of unidirectional composite materials and the stress analysis of 3-D braided composites, a new method is proposed to calculate the tensile statistical strength of the 3-D braided compos- ites. With this method, the strength of 3-D braided composites can be calculated with very large accuracy, and the statistical parameters of 3-D braided composites can be determined. The numerical result shows that the tensile statistical strength of 3-D braided composites can be predicted using this method.
基金supported by a predoctoral fellowship from the National Institutes of Health and a research grant from the National Science Foundation
文摘Introduction Cancer is an attractive target of gene therapy and currently represents the disease in most clinical trials[1]. Strategies for cancer gene therapy include: (1) stimulation of immune responses to tumor cells,(2) delivery of specific enzymes
文摘Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The model was validated using the data collected before the opening of the bridge to the public. The bridge was instrumented to conduct fullscale static and dynamic tests. The static tests were to measure the deflection of the bridge pier while the dynamic tests to measure the free vibrations of the pier due to a sudden release of the static load. Confederation Bridge is one of the longest reinforced concrete bridges in the world. It connects the province of Prince Edward Island and the province of New Brunswick in Canada. Due to its strategic location and vital role as a transportation link between these two provinces, it was designed using higher safety factors than those for typical highway bridges. After validating the present numerical model, a procedure was developed to evaluate the performance of similar bridges subjected to traffic and seismic loads. It is of interest to note that the foundation stiffness and the modulus of elasticity of the concrete have significant effects on the structural responses of the Confederation Bridge.
基金sponsored by the National Key R&D Program of China(No.2021YFA0715100)the Shenzhen Fundamental Research Program,China(No.JCYJ20220818102601004)+1 种基金the National Natural Science Foundation of China(No.41774145)the Pre-research Project on Civil Aerospace Technologies(No.D020101)of CNSA。
文摘Various models exist to explain the formation of the Tibetan Plateau,including“tectonic escape”,“pure shear thickening”,“convective removal of the lithospheric mantle”,and“lower crustal flow”model.The first two models are primarily constructed on pure mechanical models but are unable to reasonably explain the tension and shear phenomena inside the plateau.The latter two are rheological dynamic models based on deep geophysical observations.However,the spatial range of the lower crustal flow and its role in the plateau formation/uplift remain controversial.Five multi-terrane viscoplastic thermomechanical models were constructed to simulate the uplift and lithospheric structure change of the Tibetan Plateau during the post-collision stage(since 35 Ma)under the convergence of the Indian Plate.Results show that the plateau's formation begins with crustal thickening,blocked by strong terranes at the northern plateau,and expanded laterally to the east.The lithosphere thickens gradually and experiences delamination at its base,elevating temperature within the crust and forming partial melting layers in the central plateau.As convergence persists on the southern side,the northern plateau's lithosphere bends downward and undergoes delamination,further heating the crust and promoting the northward and eastward flow of partial melting layers,leading to secondary uplift around the plateau.
基金supported by the National Natural Science Foundation of China(No. 51405229)the Natural Science Foundation of Jiangsu Province of China(Nos. BK20151470,BK20171416)
文摘The pneumatic muscle actuator(PMA)has many advantages,such as good flexibility,high power/weight ratio,but its nonlinearity makes it difficult to build a static mathematical model with high precision.A new method is proposed to establish the model of PMA.The concept of hybrid elastic modulus which is related to the static characteristic of PMA is put forward,and the energy conservation law is used to achieve the expression of the hybrid elastic modulus,which can be fitted out based on experimental data,and the model of PMA can be derived from this expression.At the same time,a 3-DOF parallel mechanism(a new bionic shoulder joint)driven by five PMAs is designed.This bionic shoulder joint adopts the structure of two antagonistic PMAs actualizing a rotation control and three PMAs controlling another two rotations to get better rotation characteristics.The kinematic and dynamic characteristics of the mechanism are analyzed and a new static model of PMA is used to control it.Experimental results demonstrate the effectiveness of this new static model.
基金financially supported by the Science and Technology Project of the Ministry of Transport(Grant No.2013328352570)
文摘In order to accurately simulate strong three-dimensional (3-D) free surface flows and sediment transport, the fully 3- D non-hydrostatic pressure models are developed based on the incompressible Navier-Stokes equations and convection-diffusion equation of sediment concentration with the mixing triangle and quadrilateral grids. The governing equations are discretized with the unstructured finite volume method in order to provide conservation properties of mass and momentum, and flexibility with practical application. It is shown that it is first-order accurate on nonuniform plane two-dimensional (2-D) grids and second-order accurate on uniform plane grids. A third-order approximation of the vertical velocity at the top-layer is applied. In such a way, free surface zero stress boundary condition is satisfied maturely, and very few vertical layers are needed to give an accurate solution even for complex discontinuous flow and short wave simulation. The model is applied to four examples to simulate strong 3-D free surface flows and sediment transport where non-hydrostatic pressures have a considerable effect on the velocity field. The newly developed model is verified against analytical solutions with an excellent agreement.
文摘The 3-D seismic dataset is a key tool to analyze and understand the mechanism of structural and stratigraphic hydrocarbon(HC)trapping in the subsurface.Conventionally used subsurface seismic characterization methods for fractures are based on the theory of effective anisotropy medium.The aim of this work is to improve the structural images with dense sampling of 3-D survey to evaluate structural and stratigraphic models for reservoir development to predict reservoir quality.The present study of the Gullfaks Field,located in the Norwegian North Sea Gullfaks sector,identifies the shallowest structural elements.The steepness of westward structural dip decreases eastward during the Upper Jurassic to Lower Cretaceous deposition.Reservoir sands consist of the Middle Jurassic deltaic deposits and Lower Jurassic fluvial channel and delta plain deposits.Sediment supply steadily prevails on sea-level rise and the succession displays a regressive trend indicated by a good continuous stacking pattern.The key factor for the development of reservoirs in the Gullfaks Field is fault transmissibility with spatially distributed pressure.The majority of mapped faults with sand-to-sand contacts are non-sealing,which provide restriction for the HC flow between the fault blocks.The traps for HC accumulation occur between the post-rift and syn-rift strata,i.e.antiform set by extensional system,unconformity trap at the top of syndeposition,and structural trap due to normal faults.Overall reservoir quality in the studied area is generally excellent with average 35%porosity and permeability in the Darcy range.Our findings are useful to better understand the development of siliciclastic reservoirs in similar geological settings worldwide.