A high-accuracy multiresolution method is proposed to solve mechanics problems subject to complex shapes or irregular domains.To realize this method,we design a new wavelet basis function,by which we construct a fifth...A high-accuracy multiresolution method is proposed to solve mechanics problems subject to complex shapes or irregular domains.To realize this method,we design a new wavelet basis function,by which we construct a fifth-order numerical scheme for the approximation of multi-dimensional functions and their multiple integrals defined in complex domains.In the solution of differential equations,various derivatives of the unknown function are denoted as new functions.Then,the integral relations between these functions are applied in terms of wavelet approximation of multiple integrals.Therefore,the original equation with derivatives of various orders can be converted to a system of algebraic equations with discrete nodal values of the highest-order derivative.During the application of the proposed method,boundary conditions can be automatically included in the integration operations,and relevant matrices can be assured to exhibit perfect sparse patterns.As examples,we consider several second-order mathematics problems defined on regular and irregular domains and the fourth-order bending problems of plates with various shapes.By comparing the solutions obtained by the proposed method with the exact solutions,the new multiresolution method is found to have a convergence rate of fifth order.The solution accuracy of this method with only a few hundreds of nodes can be much higher than that of the finite element method(FEM)with tens of thousands of elements.In addition,because the accuracy order for direct approximation of a function using the proposed basis function is also fifth order,we may conclude that the accuracy of the proposed method is almost independent of the equation order and domain complexity.展开更多
In this paper, the basic formulae for the semi-analytical graded FEM on FGM members are derived. Since FGM parameters vary along three space coordinates, the parameters can be integrated in mechanical equations. There...In this paper, the basic formulae for the semi-analytical graded FEM on FGM members are derived. Since FGM parameters vary along three space coordinates, the parameters can be integrated in mechanical equations. Therefore with the parameters of a given FGM plate, problems of FGM plate under various conditions can be solved. The approach uses 1D discretization to obtain 3D solutions, which is proven to be an effective numerical method for the mechanical analyses of FGM structures. Examples of FGM plates with complex shapes and various holes are presented.展开更多
To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization ...To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mssbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.展开更多
The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized by hydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage mod...The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized by hydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage modulus below and above the glass transition temperature occurred and the complexes exhibited shape memory behaviors. The morphology of complexes was studied by using DSC, WAXD, and DMA. The results indicate that the fixed phase of this kind of novel shape memory materials is the network, and the reversible phase is the amorphous state of PEG:PMAA complex phase. The shape recoverability almost reaches 100%. This type of complexes can be regarded as a novel shape memory network.展开更多
Both four-arm star-shaped poly(ε-caprolactone) (4sPCL) and two-arm linear PCL (2LPCL) were synthesized and their inclusion complexation withα-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs) formed b...Both four-arm star-shaped poly(ε-caprolactone) (4sPCL) and two-arm linear PCL (2LPCL) were synthesized and their inclusion complexation withα-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs) formed between the PCL polymers andα-CD were characterized by 1H-NMR, DSC, TGA, WAXD, and FT-IR, respectively. Both branch arm number and molecular weight of the PCL polymers have apparent effect on the stoichiometry (CL:CD, mol:mol) of these ICs. All these analytical results indicate that the branch arms of the PCL polymers are incorporated into the hydrophobicα-CD cavities and their original crystalline properties are completely suppressed. Moreover, the inclusion complexation between two-arm linear or four-arm star-shaped PCL polymers andα-CD not only enhances the thermal stability of the guest PCL polymers but also improves that ofα-CD.展开更多
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to ...The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to the structure.So the hole-edge stress concentration is always a serious phenomenon.And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points.Most partial damage begins from these weak points.According to the complex variable functions theory,the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes.Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress function.The boundary integral equations are founded based on exact boundary conditions.Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved.Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed.And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole arc madc.It can bc concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient;and smaller angle of outer load and fiber can decrease the stress peak value.展开更多
Based on lots of field experiments and theoretical research, fully thinking the equipment and production craft characters of four high cold mill, a new cambering scheme for four high cold mill is advanced in this pape...Based on lots of field experiments and theoretical research, fully thinking the equipment and production craft characters of four high cold mill, a new cambering scheme for four high cold mill is advanced in this paper. This scheme considered the need of production of multi-specification products, as well as the control of roller ends contact. The most homogeneous transverse distribution of front tension is the control target and the homogeneous pressure distribution between rollers is the constraint condition. In this technology, working roll curve adapt the combination of cosine curve and high order curve, backup roll adapt the combination of cosine curve, straight line and high order curve. The cosine subentry of working roll and the high order curve subentry are used to control edge wave, the high order curve subentry of working roll is used to control the roll contact, the cosine subentry of backup roll is used to reduce the center wave. That’s the features of this technology. On-site testing shows that the new cambering and combination can not only manage the complex waves of normal four high cold mill effectively, but also will reduce the contact between roller ends and minish roll consumption. This technology has created economic benefits for enterprises.展开更多
The absorber is known to be vertical axisymmetric for a single-point wave energy converter(WEC). The shape of the wetted surface usually has a great influence on the absorber's hydrodynamic characteristics which a...The absorber is known to be vertical axisymmetric for a single-point wave energy converter(WEC). The shape of the wetted surface usually has a great influence on the absorber's hydrodynamic characteristics which are closely linked with the wave power conversion ability. For complex wetted surface, the hydrodynamic coefficients have been predicted traditionally by hydrodynamic software based on the BEM. However, for a systematic study of various parameters and geometries, they are too multifarious to generate so many models and data grids. This paper examines a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped and stepped surfaces based on the boundary discretization method(BDM) which overcomes the previous difficulties. In such case, by using the linear wave theory based on eigenfunction expansion matching method, the expressions of velocity potential in each domain, the added mass, radiation damping and wave excitation forces of the oscillating absorbers are obtained. The good astringency of the hydrodynamic coefficients and wave forces are obtained for various geometries when the discrete number reaches a certain value. The captured wave power for a same given draught and displacement for various geometries are calculated and compared. Numerical results show that the geometrical shape has great effect on the wave conversion performance of the absorber. For absorbers with the same outer radius and draught or displacement, the cylindrical type shows fantastic wave energy conversion ability at some given frequencies, while in the random sea wave, the parabolic and conical ones have better stabilization and applicability in wave power conversion.展开更多
Both a persulfide crystal of L-L(1), the oxidative coupling product of 1-phenyl-1H-tetrazole-5-thiol(HL), and a neutral copper(I) complex of Cu6L6(2) were self-assembled and their crystal architectures were characteri...Both a persulfide crystal of L-L(1), the oxidative coupling product of 1-phenyl-1H-tetrazole-5-thiol(HL), and a neutral copper(I) complex of Cu6L6(2) were self-assembled and their crystal architectures were characterized by CCD method. HL was converted into the persulfide L-L(1) over a metalloporphyrin catalyst with enzymatic characters under ambient conditions. Whlie in the crystal architecture of Cu6L6(2), 6 copper(I) ions were ligated by 6L-anions to construct a Cu6 ring, which just resembled the chair configuration of cyclohexane. Notably, both compounds 1 and 2 exhibit strong photoluminescence in solid state.展开更多
基金Project supported by the National Natural Science Foundation of China(No.11925204)the 111 Project(No.B14044)。
文摘A high-accuracy multiresolution method is proposed to solve mechanics problems subject to complex shapes or irregular domains.To realize this method,we design a new wavelet basis function,by which we construct a fifth-order numerical scheme for the approximation of multi-dimensional functions and their multiple integrals defined in complex domains.In the solution of differential equations,various derivatives of the unknown function are denoted as new functions.Then,the integral relations between these functions are applied in terms of wavelet approximation of multiple integrals.Therefore,the original equation with derivatives of various orders can be converted to a system of algebraic equations with discrete nodal values of the highest-order derivative.During the application of the proposed method,boundary conditions can be automatically included in the integration operations,and relevant matrices can be assured to exhibit perfect sparse patterns.As examples,we consider several second-order mathematics problems defined on regular and irregular domains and the fourth-order bending problems of plates with various shapes.By comparing the solutions obtained by the proposed method with the exact solutions,the new multiresolution method is found to have a convergence rate of fifth order.The solution accuracy of this method with only a few hundreds of nodes can be much higher than that of the finite element method(FEM)with tens of thousands of elements.In addition,because the accuracy order for direct approximation of a function using the proposed basis function is also fifth order,we may conclude that the accuracy of the proposed method is almost independent of the equation order and domain complexity.
基金Project supported by the National Natural Science Foundation of China (No. 10432030)
文摘In this paper, the basic formulae for the semi-analytical graded FEM on FGM members are derived. Since FGM parameters vary along three space coordinates, the parameters can be integrated in mechanical equations. Therefore with the parameters of a given FGM plate, problems of FGM plate under various conditions can be solved. The approach uses 1D discretization to obtain 3D solutions, which is proven to be an effective numerical method for the mechanical analyses of FGM structures. Examples of FGM plates with complex shapes and various holes are presented.
基金National Natural Science Foundation of China （51075013） Beijing Natural Science Foundation （4102035）+1 种基金 Fundamental Research Funds for the Central Universities （YWF-10-01-A09） Research Foundation of State Key Laboratory for Manufacturing Systems Engineering （Xi＇an Jiaotong University）
基金Project supported by the National Natural Science Foundation of China (Grant Nos 90505007 and 10774061)
文摘To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mssbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.
文摘The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized by hydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage modulus below and above the glass transition temperature occurred and the complexes exhibited shape memory behaviors. The morphology of complexes was studied by using DSC, WAXD, and DMA. The results indicate that the fixed phase of this kind of novel shape memory materials is the network, and the reversible phase is the amorphous state of PEG:PMAA complex phase. The shape recoverability almost reaches 100%. This type of complexes can be regarded as a novel shape memory network.
基金This work was supported by the National Natural Science Foundation of China (No. 20404007).
文摘Both four-arm star-shaped poly(ε-caprolactone) (4sPCL) and two-arm linear PCL (2LPCL) were synthesized and their inclusion complexation withα-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs) formed between the PCL polymers andα-CD were characterized by 1H-NMR, DSC, TGA, WAXD, and FT-IR, respectively. Both branch arm number and molecular weight of the PCL polymers have apparent effect on the stoichiometry (CL:CD, mol:mol) of these ICs. All these analytical results indicate that the branch arms of the PCL polymers are incorporated into the hydrophobicα-CD cavities and their original crystalline properties are completely suppressed. Moreover, the inclusion complexation between two-arm linear or four-arm star-shaped PCL polymers andα-CD not only enhances the thermal stability of the guest PCL polymers but also improves that ofα-CD.
基金supported by National Natural Science Foundation of China(No.50675209)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China(No.200724).
文摘The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to the structure.So the hole-edge stress concentration is always a serious phenomenon.And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points.Most partial damage begins from these weak points.According to the complex variable functions theory,the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes.Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress function.The boundary integral equations are founded based on exact boundary conditions.Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved.Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed.And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole arc madc.It can bc concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient;and smaller angle of outer load and fiber can decrease the stress peak value.
基金the National High Technology Research and Development Program of China(No.2019YFB2006503)the National Natural Science Foundation of China(No.51875124).
文摘Based on lots of field experiments and theoretical research, fully thinking the equipment and production craft characters of four high cold mill, a new cambering scheme for four high cold mill is advanced in this paper. This scheme considered the need of production of multi-specification products, as well as the control of roller ends contact. The most homogeneous transverse distribution of front tension is the control target and the homogeneous pressure distribution between rollers is the constraint condition. In this technology, working roll curve adapt the combination of cosine curve and high order curve, backup roll adapt the combination of cosine curve, straight line and high order curve. The cosine subentry of working roll and the high order curve subentry are used to control edge wave, the high order curve subentry of working roll is used to control the roll contact, the cosine subentry of backup roll is used to reduce the center wave. That’s the features of this technology. On-site testing shows that the new cambering and combination can not only manage the complex waves of normal four high cold mill effectively, but also will reduce the contact between roller ends and minish roll consumption. This technology has created economic benefits for enterprises.
基金supported by the National Natural Science Foundation of China(Grant Nos.11572094,51579055 and 51509048)
文摘The absorber is known to be vertical axisymmetric for a single-point wave energy converter(WEC). The shape of the wetted surface usually has a great influence on the absorber's hydrodynamic characteristics which are closely linked with the wave power conversion ability. For complex wetted surface, the hydrodynamic coefficients have been predicted traditionally by hydrodynamic software based on the BEM. However, for a systematic study of various parameters and geometries, they are too multifarious to generate so many models and data grids. This paper examines a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped and stepped surfaces based on the boundary discretization method(BDM) which overcomes the previous difficulties. In such case, by using the linear wave theory based on eigenfunction expansion matching method, the expressions of velocity potential in each domain, the added mass, radiation damping and wave excitation forces of the oscillating absorbers are obtained. The good astringency of the hydrodynamic coefficients and wave forces are obtained for various geometries when the discrete number reaches a certain value. The captured wave power for a same given draught and displacement for various geometries are calculated and compared. Numerical results show that the geometrical shape has great effect on the wave conversion performance of the absorber. For absorbers with the same outer radius and draught or displacement, the cylindrical type shows fantastic wave energy conversion ability at some given frequencies, while in the random sea wave, the parabolic and conical ones have better stabilization and applicability in wave power conversion.
基金Supported by the National Natural Science Foundation of China(No.20771073)the Third Project of"211"in Guangdong Province,China.
文摘Both a persulfide crystal of L-L(1), the oxidative coupling product of 1-phenyl-1H-tetrazole-5-thiol(HL), and a neutral copper(I) complex of Cu6L6(2) were self-assembled and their crystal architectures were characterized by CCD method. HL was converted into the persulfide L-L(1) over a metalloporphyrin catalyst with enzymatic characters under ambient conditions. Whlie in the crystal architecture of Cu6L6(2), 6 copper(I) ions were ligated by 6L-anions to construct a Cu6 ring, which just resembled the chair configuration of cyclohexane. Notably, both compounds 1 and 2 exhibit strong photoluminescence in solid state.
