Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natura...Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.展开更多
In this manuscript,a reduced(3+1)-dimensional nonlinear evolution equation is studied.We first construct the bilinear formalism of the equation by using the binary Bell polynomials theory,then explore a lump solution ...In this manuscript,a reduced(3+1)-dimensional nonlinear evolution equation is studied.We first construct the bilinear formalism of the equation by using the binary Bell polynomials theory,then explore a lump solution to the special case for z=x.Furthermore,a more general form of lump solution of the equation is found which possesses seven arbitrary parameters and four constraint conditions.By cutting the lump by the induced soliton(s),lumpoff and instanton/rogue wave solutions are also constructed by the more general form of lump solution.展开更多
With the development of computer technology and finite element method, the priority research area of plasticforming has focused on 3D FE simulation of forming processes for components with complicated geometrical shap...With the development of computer technology and finite element method, the priority research area of plasticforming has focused on 3D FE simulation of forming processes for components with complicated geometrical shape.These processes have complex deforming mechanism, and different sections have different deforming characteristics.Therefore, for making a simple, convenient, and practical analysis of its deforming law, how to obtain deformationinformation of key sections from the results of 3D FE simulation has become one of problems urgently to be solved.So, a method of obtaining deformation information by tracing deformation from sections for 3D FE simulation hasbeen proposed. From the deformation information got by this method, the deformation law of key locations and thewhole deforming body can be obtained. This method can also help to compare the result from FE simulation withthat from physical modeling. Key procedures of this method have been presented in detail, and it has been testedby applying to 3D FE simulation of precision forging of the blade with a damper platform. The result shows thatthe method is practicable and reliable, and it can also be applied to 3D FE simulation of plastic forming processes ofother components.展开更多
Based on the characteristics of 3D bulk forming process, the arbitrary Lagrangian-Eulerian (ALE) formulation-based FEM is studied, and a prediction-correction ALE-based FEM is proposed which integrates the advantages ...Based on the characteristics of 3D bulk forming process, the arbitrary Lagrangian-Eulerian (ALE) formulation-based FEM is studied, and a prediction-correction ALE-based FEM is proposed which integrates the advantages of precisely predicting the boundary configuration of the deformed material, and of efficiently avoiding hexahedron remeshing processes. The key idea of the prediction-correction ALE FEM is elaborated in detail. Accordingly, the strategy of mesh quality control, one of the key enabling techniques for the 3D bulk forming process numerical simulation by the prediction-correction ALE FEM is carefully investigated, and the algorithm for hexahedral element refinement is formulated based on the mesh distortion energy.展开更多
<正> In this paper the entanglement of pure 3-qubit states is discussed.The local unitary(LU)polynomialinvariants that are closely related to the canonical forms are constructed and the relations of the coeffici...<正> In this paper the entanglement of pure 3-qubit states is discussed.The local unitary(LU)polynomialinvariants that are closely related to the canonical forms are constructed and the relations of the coefficients of thecanonical forms are given.Then the stochastic local operations and classical communication(SLOCC)classification ofthe states are discussed on the basis of the canonical forms,and the symmetric canonical form of the states without3-tangle is discussed.Finally,we give the relation between the LU polynomial invariants and SLOCC classification.展开更多
The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric const...The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric constant, anomalous hysteresis and long-lasting polarization for CH_3NH_3PbI_3 originate from the formed CH_3NH_3 at the heterojunction. It is found that the induced weak EPS by the reorientation of CH_3NH_3 sub-group along the built-in electric field enables us to effectively increase the ordering of entire lead-halide framework. In addition, the heterojunction has an advantage of channel separation between carrier transport and electron diffusion. These properties of the heterojunction are the main origin of the high efficiency of CH_3NH_3PbI_3 solar cells.展开更多
MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X...MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size (5.2*2.1*1.2 cm) and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.展开更多
Background:The perception of visual forms is crucial for effective interactions with our environment and for the recognition of visual objects.Thus,to determine the codes underlying this function is a fundamental theo...Background:The perception of visual forms is crucial for effective interactions with our environment and for the recognition of visual objects.Thus,to determine the codes underlying this function is a fundamental theoretical objective in the study of the visual forms perception.The vast majority of research in the field is based on a hypothetico-deductive approach.Thus,we first begin by formulating a theory,then we make predictions and finally we conduct experimental tests.After decades of application of this approach,the field remains far from having a consensus as to the traits underlying the representation of visual form.Our goal is to determine,without theoretical a priori or any bias whatsoever,the information underlying the discrimination and recognition of 3D visual forms in normal human adults.Methods:To this end,the adaptive bubble technique developed by Wang et al.[2011]is applied on six 3D synthetic objects under varying views from one test to another.This technique is based on the presentation of stimuli that are partially revealed through Gaussian windows,the location of which is random and the number of which is established in such a way as to maintain an established performance criterion.Gradually,the experimental program uses participants’performance to determine the stimulus regions that participants use to recognize objects.The synthetic objects used in this study are unfamiliar and were generated from a program produced at C.Edward Connor’s lab,Johns Hopkins University School of Medicine.Results:The results were integrated across participants to establish regions of presented stimuli that determine the observers’ability to recognize them-i.e.,diagnostic attributes.The results will be reported in graphical form with a Z scores mapping that will be superimposed on silhouettes of the objects presented during the experiment.This mapping makes it possible to quantify the importance of the different regions on the visible surface of an object for its recognition by the participants.Conclusions:The diagnostic attributes that have been identified are the best described in terms of surface fragments.Some of these fragments are located on or near the outer edge of the stimulus while others are relatively distant.The overlap is minimal between the effective attributes for the different points of view of the same object.This suggests that the traits underlying the recognition of objects are specific to the point of view.In other words,they do not generalize through the points of view.展开更多
基金financially supported by the Beijing Natural Science Foundation for Young Scientists(Grant No.8214052)the Talent Fund of Beijing Jiaotong University(Grant No.2021RC226)the State Key Laboratory for GeoMechanics and Deep Underground Engineering,China University of Mining and Technology(Grant No.SKLGDUEK2115).
文摘Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11675084 and 11435005)the Fund from the Educational Commission of Zhejiang Province,China(Grant No.Y201737177)+1 种基金Ningbo Natural Science Foundation(Grant No.2015A610159)the K C Wong Magna Fund in Ningbo University
文摘In this manuscript,a reduced(3+1)-dimensional nonlinear evolution equation is studied.We first construct the bilinear formalism of the equation by using the binary Bell polynomials theory,then explore a lump solution to the special case for z=x.Furthermore,a more general form of lump solution of the equation is found which possesses seven arbitrary parameters and four constraint conditions.By cutting the lump by the induced soliton(s),lumpoff and instanton/rogue wave solutions are also constructed by the more general form of lump solution.
基金The authors would like to express their appreciation for the financial support of the National Science Foundation of China for Distinguished Young Scholars (50225518), the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institution of MOE,PRC,the fund of the Developing Program for Outstanding Persons in NWPU,and Natural Foundation of Shaanxi Province (2002E223)for the present research work.
文摘With the development of computer technology and finite element method, the priority research area of plasticforming has focused on 3D FE simulation of forming processes for components with complicated geometrical shape.These processes have complex deforming mechanism, and different sections have different deforming characteristics.Therefore, for making a simple, convenient, and practical analysis of its deforming law, how to obtain deformationinformation of key sections from the results of 3D FE simulation has become one of problems urgently to be solved.So, a method of obtaining deformation information by tracing deformation from sections for 3D FE simulation hasbeen proposed. From the deformation information got by this method, the deformation law of key locations and thewhole deforming body can be obtained. This method can also help to compare the result from FE simulation withthat from physical modeling. Key procedures of this method have been presented in detail, and it has been testedby applying to 3D FE simulation of precision forging of the blade with a damper platform. The result shows thatthe method is practicable and reliable, and it can also be applied to 3D FE simulation of plastic forming processes ofother components.
基金the National Natural Science Foundation of China(No.50275094).
文摘Based on the characteristics of 3D bulk forming process, the arbitrary Lagrangian-Eulerian (ALE) formulation-based FEM is studied, and a prediction-correction ALE-based FEM is proposed which integrates the advantages of precisely predicting the boundary configuration of the deformed material, and of efficiently avoiding hexahedron remeshing processes. The key idea of the prediction-correction ALE FEM is elaborated in detail. Accordingly, the strategy of mesh quality control, one of the key enabling techniques for the 3D bulk forming process numerical simulation by the prediction-correction ALE FEM is carefully investigated, and the algorithm for hexahedral element refinement is formulated based on the mesh distortion energy.
基金The project supported by National Natural Science Foundation of China under Grant No. 6J3433050 and the Natural Science Foundation of Xuzhou Normal University （Key Project） under Grant No. 03XLA04
文摘<正> In this paper the entanglement of pure 3-qubit states is discussed.The local unitary(LU)polynomialinvariants that are closely related to the canonical forms are constructed and the relations of the coefficients of thecanonical forms are given.Then the stochastic local operations and classical communication(SLOCC)classification ofthe states are discussed on the basis of the canonical forms,and the symmetric canonical form of the states without3-tangle is discussed.Finally,we give the relation between the LU polynomial invariants and SLOCC classification.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos. 20060006024 and 20080013006Chinese Ministry of Education, by the National Natural Science Foundation of China under Grant No. 60772023+2 种基金by the Open Fund of the State Key Laboratory of Software Development Environment under Grant No. SKLSDE-07-001Beijing University of Aeronautics and Astronauticsby the National Basic Research Program of China (973 Program) under Grant No. 2005CB321901
基金Supported by the National Natural Science Foundation of China under Grant No 61875235the Ph.D. Programs Foundation of Ministry of Education of China under Grant No 20130009110008the Beijing Municipal Education Commission Project under Grant No KM201210015008
文摘The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric constant, anomalous hysteresis and long-lasting polarization for CH_3NH_3PbI_3 originate from the formed CH_3NH_3 at the heterojunction. It is found that the induced weak EPS by the reorientation of CH_3NH_3 sub-group along the built-in electric field enables us to effectively increase the ordering of entire lead-halide framework. In addition, the heterojunction has an advantage of channel separation between carrier transport and electron diffusion. These properties of the heterojunction are the main origin of the high efficiency of CH_3NH_3PbI_3 solar cells.
文摘MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size (5.2*2.1*1.2 cm) and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.
文摘Background:The perception of visual forms is crucial for effective interactions with our environment and for the recognition of visual objects.Thus,to determine the codes underlying this function is a fundamental theoretical objective in the study of the visual forms perception.The vast majority of research in the field is based on a hypothetico-deductive approach.Thus,we first begin by formulating a theory,then we make predictions and finally we conduct experimental tests.After decades of application of this approach,the field remains far from having a consensus as to the traits underlying the representation of visual form.Our goal is to determine,without theoretical a priori or any bias whatsoever,the information underlying the discrimination and recognition of 3D visual forms in normal human adults.Methods:To this end,the adaptive bubble technique developed by Wang et al.[2011]is applied on six 3D synthetic objects under varying views from one test to another.This technique is based on the presentation of stimuli that are partially revealed through Gaussian windows,the location of which is random and the number of which is established in such a way as to maintain an established performance criterion.Gradually,the experimental program uses participants’performance to determine the stimulus regions that participants use to recognize objects.The synthetic objects used in this study are unfamiliar and were generated from a program produced at C.Edward Connor’s lab,Johns Hopkins University School of Medicine.Results:The results were integrated across participants to establish regions of presented stimuli that determine the observers’ability to recognize them-i.e.,diagnostic attributes.The results will be reported in graphical form with a Z scores mapping that will be superimposed on silhouettes of the objects presented during the experiment.This mapping makes it possible to quantify the importance of the different regions on the visible surface of an object for its recognition by the participants.Conclusions:The diagnostic attributes that have been identified are the best described in terms of surface fragments.Some of these fragments are located on or near the outer edge of the stimulus while others are relatively distant.The overlap is minimal between the effective attributes for the different points of view of the same object.This suggests that the traits underlying the recognition of objects are specific to the point of view.In other words,they do not generalize through the points of view.
