The casting-forging combined technique and the closed die forging without flash-less are both new developed material working methods. The former can not only decrease forming operations of forgings, but also increase ...The casting-forging combined technique and the closed die forging without flash-less are both new developed material working methods. The former can not only decrease forming operations of forgings, but also increase the material utilization ratio. Therefore, it is applied to produce more complex forgings. The latter is required for forging precise parts without burrs. The alternator pole is a complex forging, which was usually produced by hot forging, upsetting-extrusion or upsetting-extrusion and bending processes. During these processes, not only the forming force is higher, but the material of burrs accounts for 30 percent or so of total required material. And burrs are difficult to remove in the sequential machining process. In accordance with defects exiting in current manufacturing of alternator poles by upsetting-extruding process, such as more material demand, higher forming force and difficulty of next machining, a casting-forging precision process of alternator poles was developed and investigated in this paper. In the process, the pole was formed by two operations. One is the pre-forming operation by casting. The other is the final forming operation by the closed precision forging process. This can not only shorten processes, decrease material and power demand, but also increase precision of forgings. First, the casting blocker was designed considering the casting process and the forging ratio and the mode of deformation. Then the die structure for closed precision forging was designed, and the closing device for forging dies with spring assemblies in order to provide the necessary closing force was also designed. Finally the forming processes was investigated by test and numerical simulation method to optimum process parameters and die structure design parameters. The result can provide basis for applying the process to manufacture poles in practice.展开更多
As a newly developed precision technology, casting-forging complex near net forming process is utilized to produce complex components with a short lead time, low cost and high precision, thus to accelerate the respons...As a newly developed precision technology, casting-forging complex near net forming process is utilized to produce complex components with a short lead time, low cost and high precision, thus to accelerate the response speed of the market and enhance the competitive power of products. In this paper, the casting-forging complex near net forming process of alternator claw pole was developed and investigated with a combination of experimental and numerical simulation method. Qualified near net workpiece was manufactured, mechanical parameter and relative field information during the forming process was also obtained. While the alternator claw-pole is processed with this technology, the forming force is small, the process is short and the quality of forgings is perfect. Therefore, the complex casting-forging near net forming process of claw-pole is an energy and material saving technology, which will have a vast developing and application prospect in the future.展开更多
In order to meet the requirements of high reliability,long-lifetime and lightweight in a new generation of aerospace,aviation,high-speed train,and energy power equipment,integrated components are urgently needed to re...In order to meet the requirements of high reliability,long-lifetime and lightweight in a new generation of aerospace,aviation,high-speed train,and energy power equipment,integrated components are urgently needed to replace traditional multi-piece,welded components.The applications of integrated components involve in a series of large-size,complex-shaped,highperformance components made of difficult-to-deform materials,which present a huge challenge for forming ultra-large size integrated components.In this paper,the developments and perspectives of several extreme forming technologies are reviewed,including the sheet hydroforming of ultra-large curved components,dieless hydroforming of ellipsoidal shells,radial-axial ring rolling of rings,in situ manufacturing process of flanges,and local isothermal forging of titanium alloy components.The principle and processes for controlling deformation are briefly illustrated.The forming of typical ultra-large size integrated components and industrial applications are introduced,such as the high strength aluminum alloy,3m in diameter,integrated tank dome first formed by using a sheet blank with a thickness the same as the final component,and a 16m diameter,integrated steel ring rolled by using a single billet.The trends for extreme forming of ultra-large size integrated components are discussed with a goal of providing ideas and fundamental guidance for the further development of new forming processes for extreme-size integrated components in the future.展开更多
It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of pre...It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.展开更多
This paper presented a model of integrated reverse engineering system and set up its various data output flowchart, which is easy to be associated with other systems. The idea of integrated reverse engineer is introdu...This paper presented a model of integrated reverse engineering system and set up its various data output flowchart, which is easy to be associated with other systems. The idea of integrated reverse engineer is introduced to the system of forming sheet metal with complex surface and using IDEF0 method sets up the function model of the system. The freeform surface reconstruction and CAD modeling of the system are described and decomposed. This paper discussed some problems, such as the feature expression, feature modeling and feature translation of the sheet parts and dies.展开更多
An original plastic equivalent model was proposed to solve the problem of excessive FEM simulation time when designing the press bend forming path and optimizing the process parameters of press bend forming of the int...An original plastic equivalent model was proposed to solve the problem of excessive FEM simulation time when designing the press bend forming path and optimizing the process parameters of press bend forming of the integrally stiffened aircraft panels. Based on the in-depth analysis of the mechanics of the bending and springback of the detailed model and the equivalent model of the integral panels,the plastic equivalent model of the virtual material with special initial yield stress and hardening coefficients was constructed. FEM results indicate that the objective of getting the similar contour with the same press bend forming path is achieved with the error less than 6%,and the efficiency of FEM simulation is improved by more than 80%. The plastic equivalent model is valuable and essential for the further research on the press bend forming process of large scale complicated integral panels.展开更多
In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response...In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response surface,and the genetic algorithm.First,a multi-step press bend forming FEM equivalent model was established,with which the FEM experiments designed with Taguchi method were performed.Then,the BP neural network response surface was developed with the sample data from the FEM experiments.Furthermore,genetic algorithm was applied with the neural network response surface as the objective function. Finally,verification was carried out on a simple curvature grid-type stiffened panel.The forming error of the panel formed with the optimal path is only 0.098 39 and the calculating efficiency has been improved by 77%.Therefore,this novel optimization method is quite efficient and indispensable for the press bend forming path designing.展开更多
This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical e...This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical elements such as scales,modes,and compositional styles,illuminating shared threads and distinctive attributes that characterize Chinese and Western music.Against the backdrop of contemporary global dynamics,the research investigates the ongoing integration of these musical cultures.It explores the impact of globalization and technological advancements,revealing instances of cross-cultural collaboration and the emergence of hybrid musical forms.Augmenting theoretical discussions with concrete case studies,the paper offers illuminating examples of how Chinese and Western musical elements interweave,contributing to the evolving landscape of global music.This research not only advances scholarly understanding but also contributes practical insights for musicians,educators,and enthusiasts navigating the evolving dynamics of cross-cultural musical expression.By elucidating the intricate relationship between Chinese and Western music cultures,the paper underscores the richness borne out of their interaction and the cultural synthesis that defines contemporary musical landscapes.展开更多
Interesting classifications of basinogenesis and basins were proposed by many scientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamic angle . I...Interesting classifications of basinogenesis and basins were proposed by many scientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamic angle . In order to more comprehensively understand them for more effectively guiding prospecting and exploration, the author integrates the two methods of analysis with each other and proposes an integrative classification .According to the historical - dynamic integrative classification,basinogenesis and basins can be.di-vided into three types :oceanic crust type ,embryo-continental (transitional )crust type and continental crust type .Oceanic crust type can be subdivided into mobile region type (mainly tenskmal )and stable region type . Embryo-continental type includes pre-geosynclinal type (divisible into several mobile region types and stable region types with tensional type predominating among mobile region types ) and ear ly-geosynclinal type (mainly tenskmal ) .Continental crust type includes late- geosynclinal (fold belt)type (compressional or tenskmal ),platform type (mainly sinking and rarely tenskmal subsidence-aulacogen)and geodepression (diwa )type (compressional , tenskmal or compresskmal-tenskmal ).展开更多
Interesting classifications of basinogenesis and basins were proposed by many seientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamie angle. In...Interesting classifications of basinogenesis and basins were proposed by many seientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamie angle. In order to more comprehensively understand them for moore effectively guidlilg prospeeting and exploration, the author integrates the two methods of analysis wilh cach other and proposes an integrative classification. According to the historieal-dynamic integrative classification, basinogenesis and basins can be divided into three types: occanic erust type. embryo-continental (transitional ) erust iype and continental crust type. Oceanie erust type call be subdivided into mobile region type (mainly tensional) and stable region type. Embryo-continental type includes pre-geosynclinal type (divisible into several mobile region types and stable region types with tensional type predoiminating among mobile region trpes) and early-geosynelinal type (mainly tensional). Continental erust type ineludes late-gcosynelinal (fold belt) type (compressional or tensional), platform type (mainly sinking and rarely tensional subsidence-aulacogen) and gcodepression (diwa) type (compressional, tensional or compressional-tensional ).展开更多
Whether to adopt the meaning-oriented or form-oriented approach in EFL teaching has been in hot academic debate in the past decades. This paper investigates the literature contribution on these two methods, attempts a...Whether to adopt the meaning-oriented or form-oriented approach in EFL teaching has been in hot academic debate in the past decades. This paper investigates the literature contribution on these two methods, attempts an integration of the two,and introduces a teaching experiment of EFL reading and writing at China Agricultural University.展开更多
In this paper, firstly using different method and technique we derive the cor-responding integral representation formulas of (0, q)(q 〉 0) differential forms for the twotypes of the bounded domains in complex sub...In this paper, firstly using different method and technique we derive the cor-responding integral representation formulas of (0, q)(q 〉 0) differential forms for the twotypes of the bounded domains in complex submanifolds with codimension-m. Secondly weobtain the unified integral representation formulas of (0, q)(q 〉 0) differential forms for thegeneral bounded domain in complex submanifold with codimension-m, which include Hatzi-afratis formula, i.e. Koppelman type integral formula for the bounded domain with smoothboundary in analytic varieties. In particular, when m -- 0, we obtain the unified integralrepresentation formulas of (0, q)(q 〉 0) differential forms for general bounded domain in Cn,which are the generalization and the embodiment of Koppelman-Leray formula.展开更多
Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large de...Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35(the ratio between the maximum and minimum diameters of the part) can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes.展开更多
The important notions and results of the integral invariants of Poincard and Cartan-Poincard and the relationship between integral invariant and invariant form established first by E. Cartan in the classical mechanics...The important notions and results of the integral invariants of Poincard and Cartan-Poincard and the relationship between integral invariant and invariant form established first by E. Cartan in the classical mechanics are generalized to Hamilton mechanics on Kiihler manifold, by the theory of modern geometry and advanced calculus, to get the corresponding wider arid deeper results. differential展开更多
With the help of skew-symmetric differential forms the hidden properties of the mathematical physics equations are revealed. It is shown that the equations of mathematical physics can describe the emergence of various...With the help of skew-symmetric differential forms the hidden properties of the mathematical physics equations are revealed. It is shown that the equations of mathematical physics can describe the emergence of various structures and formations such as waves, vortices, turbulent pulsations and others. Such properties of the mathematical physics equations, which are hidden (they appear only in the process of solving these equations), depend on the consistency of derivatives in partial differential equations and on the consistency of equations, if the equations of mathematical physics are a set of equations. This is due to the integrability of mathematical physics equations. It is shown that the equations of mathematical physics can have double solutions, namely, the solutions on the original coordinate space and the solutions on integrable structures that are realized discretely (due to any degrees of freedom). The transition from the solutions of the first type to one of the second type describes discrete transitions and the processes of origin of various structures and observable formations. Only mathematical physics equations, on what no additional conditions such as the integrability conditions are imposed, can possess such properties. The results of the present paper were obtained with the help of skew-symmetric differential forms.展开更多
The reccnt Alcatel Lucent failure is an example of how many mergers run into considerable implementing difficulties in the months following their launch. Despite promising perspectives,no coherent whole seems to come ...The reccnt Alcatel Lucent failure is an example of how many mergers run into considerable implementing difficulties in the months following their launch. Despite promising perspectives,no coherent whole seems to come out of the merger,just as anticipated synergies have a hard time materializing.展开更多
A semi-direct sum of two Lie algebras of four-by-four matrices is presented,and a discrete four-by-fourmatrix spectral problem is introduced.A hierarchy of discrete integrable coupling systems is derived.The obtainedi...A semi-direct sum of two Lie algebras of four-by-four matrices is presented,and a discrete four-by-fourmatrix spectral problem is introduced.A hierarchy of discrete integrable coupling systems is derived.The obtainedintegrable coupling systems are all written in their Hamiltonian forms by the discrete variational identity.Finally,we prove that the lattice equations in the obtained integrable coupling systems are all Liouville integrable discreteHamiltonian systems.展开更多
We obtain the global weighted estimates for Jacobian J(x,f)and its subdeterminants, as well as the components of K-quasiconformalmappings in L^s(μ)-averagingdomains. To develop these estimates, both local and global ...We obtain the global weighted estimates for Jacobian J(x,f)and its subdeterminants, as well as the components of K-quasiconformalmappings in L^s(μ)-averagingdomains. To develop these estimates, both local and global weighted Ponincaré inequalities for differential forms are established.展开更多
文摘The casting-forging combined technique and the closed die forging without flash-less are both new developed material working methods. The former can not only decrease forming operations of forgings, but also increase the material utilization ratio. Therefore, it is applied to produce more complex forgings. The latter is required for forging precise parts without burrs. The alternator pole is a complex forging, which was usually produced by hot forging, upsetting-extrusion or upsetting-extrusion and bending processes. During these processes, not only the forming force is higher, but the material of burrs accounts for 30 percent or so of total required material. And burrs are difficult to remove in the sequential machining process. In accordance with defects exiting in current manufacturing of alternator poles by upsetting-extruding process, such as more material demand, higher forming force and difficulty of next machining, a casting-forging precision process of alternator poles was developed and investigated in this paper. In the process, the pole was formed by two operations. One is the pre-forming operation by casting. The other is the final forming operation by the closed precision forging process. This can not only shorten processes, decrease material and power demand, but also increase precision of forgings. First, the casting blocker was designed considering the casting process and the forging ratio and the mode of deformation. Then the die structure for closed precision forging was designed, and the closing device for forging dies with spring assemblies in order to provide the necessary closing force was also designed. Finally the forming processes was investigated by test and numerical simulation method to optimum process parameters and die structure design parameters. The result can provide basis for applying the process to manufacture poles in practice.
文摘As a newly developed precision technology, casting-forging complex near net forming process is utilized to produce complex components with a short lead time, low cost and high precision, thus to accelerate the response speed of the market and enhance the competitive power of products. In this paper, the casting-forging complex near net forming process of alternator claw pole was developed and investigated with a combination of experimental and numerical simulation method. Qualified near net workpiece was manufactured, mechanical parameter and relative field information during the forming process was also obtained. While the alternator claw-pole is processed with this technology, the forming force is small, the process is short and the quality of forgings is perfect. Therefore, the complex casting-forging near net forming process of claw-pole is an energy and material saving technology, which will have a vast developing and application prospect in the future.
基金This work was funded in part by the National Key Research and Development Program of China(2017YFB0306304)the National Natural Science Foundation of China(51705102,U1637209).The authors wish to express their gratitude for the funding.
文摘In order to meet the requirements of high reliability,long-lifetime and lightweight in a new generation of aerospace,aviation,high-speed train,and energy power equipment,integrated components are urgently needed to replace traditional multi-piece,welded components.The applications of integrated components involve in a series of large-size,complex-shaped,highperformance components made of difficult-to-deform materials,which present a huge challenge for forming ultra-large size integrated components.In this paper,the developments and perspectives of several extreme forming technologies are reviewed,including the sheet hydroforming of ultra-large curved components,dieless hydroforming of ellipsoidal shells,radial-axial ring rolling of rings,in situ manufacturing process of flanges,and local isothermal forging of titanium alloy components.The principle and processes for controlling deformation are briefly illustrated.The forming of typical ultra-large size integrated components and industrial applications are introduced,such as the high strength aluminum alloy,3m in diameter,integrated tank dome first formed by using a sheet blank with a thickness the same as the final component,and a 16m diameter,integrated steel ring rolled by using a single billet.The trends for extreme forming of ultra-large size integrated components are discussed with a goal of providing ideas and fundamental guidance for the further development of new forming processes for extreme-size integrated components in the future.
基金Project(51305334)supported by the National Natural Science Foundation of ChinaProject(51335009)supported by the National Natural Science Foundation of China for Key Program+1 种基金Project(CXY1442(4))supported by the Science and Technology Planning Project of Xi’an,ChinaProject supported by Shaanxi Province Postdoctoral Science Research Program of China
文摘It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.
基金The Research Fund for the Doctoral Pro- gram of Higher Education( 2 0 0 0 0 2 4838)
文摘This paper presented a model of integrated reverse engineering system and set up its various data output flowchart, which is easy to be associated with other systems. The idea of integrated reverse engineer is introduced to the system of forming sheet metal with complex surface and using IDEF0 method sets up the function model of the system. The freeform surface reconstruction and CAD modeling of the system are described and decomposed. This paper discussed some problems, such as the feature expression, feature modeling and feature translation of the sheet parts and dies.
基金Project(50675010) supported by the National Natural Science Foundation of China
文摘An original plastic equivalent model was proposed to solve the problem of excessive FEM simulation time when designing the press bend forming path and optimizing the process parameters of press bend forming of the integrally stiffened aircraft panels. Based on the in-depth analysis of the mechanics of the bending and springback of the detailed model and the equivalent model of the integral panels,the plastic equivalent model of the virtual material with special initial yield stress and hardening coefficients was constructed. FEM results indicate that the objective of getting the similar contour with the same press bend forming path is achieved with the error less than 6%,and the efficiency of FEM simulation is improved by more than 80%. The plastic equivalent model is valuable and essential for the further research on the press bend forming process of large scale complicated integral panels.
基金Project(20091102110021)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response surface,and the genetic algorithm.First,a multi-step press bend forming FEM equivalent model was established,with which the FEM experiments designed with Taguchi method were performed.Then,the BP neural network response surface was developed with the sample data from the FEM experiments.Furthermore,genetic algorithm was applied with the neural network response surface as the objective function. Finally,verification was carried out on a simple curvature grid-type stiffened panel.The forming error of the panel formed with the optimal path is only 0.098 39 and the calculating efficiency has been improved by 77%.Therefore,this novel optimization method is quite efficient and indispensable for the press bend forming path designing.
文摘This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical elements such as scales,modes,and compositional styles,illuminating shared threads and distinctive attributes that characterize Chinese and Western music.Against the backdrop of contemporary global dynamics,the research investigates the ongoing integration of these musical cultures.It explores the impact of globalization and technological advancements,revealing instances of cross-cultural collaboration and the emergence of hybrid musical forms.Augmenting theoretical discussions with concrete case studies,the paper offers illuminating examples of how Chinese and Western musical elements interweave,contributing to the evolving landscape of global music.This research not only advances scholarly understanding but also contributes practical insights for musicians,educators,and enthusiasts navigating the evolving dynamics of cross-cultural musical expression.By elucidating the intricate relationship between Chinese and Western music cultures,the paper underscores the richness borne out of their interaction and the cultural synthesis that defines contemporary musical landscapes.
文摘Interesting classifications of basinogenesis and basins were proposed by many scientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamic angle . In order to more comprehensively understand them for more effectively guiding prospecting and exploration, the author integrates the two methods of analysis with each other and proposes an integrative classification .According to the historical - dynamic integrative classification,basinogenesis and basins can be.di-vided into three types :oceanic crust type ,embryo-continental (transitional )crust type and continental crust type .Oceanic crust type can be subdivided into mobile region type (mainly tenskmal )and stable region type . Embryo-continental type includes pre-geosynclinal type (divisible into several mobile region types and stable region types with tensional type predominating among mobile region types ) and ear ly-geosynclinal type (mainly tenskmal ) .Continental crust type includes late- geosynclinal (fold belt)type (compressional or tenskmal ),platform type (mainly sinking and rarely tenskmal subsidence-aulacogen)and geodepression (diwa )type (compressional , tenskmal or compresskmal-tenskmal ).
文摘Interesting classifications of basinogenesis and basins were proposed by many seientists. They classified basinogenesis and basins mainly from a single angle, either from a historical angle or from a dynamie angle. In order to more comprehensively understand them for moore effectively guidlilg prospeeting and exploration, the author integrates the two methods of analysis wilh cach other and proposes an integrative classification. According to the historieal-dynamic integrative classification, basinogenesis and basins can be divided into three types: occanic erust type. embryo-continental (transitional ) erust iype and continental crust type. Oceanie erust type call be subdivided into mobile region type (mainly tensional) and stable region type. Embryo-continental type includes pre-geosynclinal type (divisible into several mobile region types and stable region types with tensional type predoiminating among mobile region trpes) and early-geosynelinal type (mainly tensional). Continental erust type ineludes late-gcosynelinal (fold belt) type (compressional or tensional), platform type (mainly sinking and rarely tensional subsidence-aulacogen) and gcodepression (diwa) type (compressional, tensional or compressional-tensional ).
文摘Whether to adopt the meaning-oriented or form-oriented approach in EFL teaching has been in hot academic debate in the past decades. This paper investigates the literature contribution on these two methods, attempts an integration of the two,and introduces a teaching experiment of EFL reading and writing at China Agricultural University.
文摘In this paper, firstly using different method and technique we derive the cor-responding integral representation formulas of (0, q)(q 〉 0) differential forms for the twotypes of the bounded domains in complex submanifolds with codimension-m. Secondly weobtain the unified integral representation formulas of (0, q)(q 〉 0) differential forms for thegeneral bounded domain in complex submanifold with codimension-m, which include Hatzi-afratis formula, i.e. Koppelman type integral formula for the bounded domain with smoothboundary in analytic varieties. In particular, when m -- 0, we obtain the unified integralrepresentation formulas of (0, q)(q 〉 0) differential forms for general bounded domain in Cn,which are the generalization and the embodiment of Koppelman-Leray formula.
基金Funded by the National Natural Science Foundation of China(No.51205260)
文摘Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35(the ratio between the maximum and minimum diameters of the part) can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes.
文摘The important notions and results of the integral invariants of Poincard and Cartan-Poincard and the relationship between integral invariant and invariant form established first by E. Cartan in the classical mechanics are generalized to Hamilton mechanics on Kiihler manifold, by the theory of modern geometry and advanced calculus, to get the corresponding wider arid deeper results. differential
文摘With the help of skew-symmetric differential forms the hidden properties of the mathematical physics equations are revealed. It is shown that the equations of mathematical physics can describe the emergence of various structures and formations such as waves, vortices, turbulent pulsations and others. Such properties of the mathematical physics equations, which are hidden (they appear only in the process of solving these equations), depend on the consistency of derivatives in partial differential equations and on the consistency of equations, if the equations of mathematical physics are a set of equations. This is due to the integrability of mathematical physics equations. It is shown that the equations of mathematical physics can have double solutions, namely, the solutions on the original coordinate space and the solutions on integrable structures that are realized discretely (due to any degrees of freedom). The transition from the solutions of the first type to one of the second type describes discrete transitions and the processes of origin of various structures and observable formations. Only mathematical physics equations, on what no additional conditions such as the integrability conditions are imposed, can possess such properties. The results of the present paper were obtained with the help of skew-symmetric differential forms.
文摘The reccnt Alcatel Lucent failure is an example of how many mergers run into considerable implementing difficulties in the months following their launch. Despite promising perspectives,no coherent whole seems to come out of the merger,just as anticipated synergies have a hard time materializing.
基金the Natural Science Foundation of Shandong Province under Grant No.Q2006A04
文摘A semi-direct sum of two Lie algebras of four-by-four matrices is presented,and a discrete four-by-fourmatrix spectral problem is introduced.A hierarchy of discrete integrable coupling systems is derived.The obtainedintegrable coupling systems are all written in their Hamiltonian forms by the discrete variational identity.Finally,we prove that the lattice equations in the obtained integrable coupling systems are all Liouville integrable discreteHamiltonian systems.
文摘We obtain the global weighted estimates for Jacobian J(x,f)and its subdeterminants, as well as the components of K-quasiconformalmappings in L^s(μ)-averagingdomains. To develop these estimates, both local and global weighted Ponincaré inequalities for differential forms are established.