This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials (FGMs). First, a Laplace transform approach is used to handle the time variable. Then, a f...This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials (FGMs). First, a Laplace transform approach is used to handle the time variable. Then, a fundamental solution in Laplace space for FGMs is constructed. Next, a hybrid graded element is formulated based on the obtained fundamental solution and a frame field. As a result, the graded properties of FGMs are naturally reflected by using the fundamental solution to interpolate the intra-element field. Further, Stefest's algorithm is employed to convert the results in Laplace space back into the time-space domain. Finally, the performance of the proposed method is assessed by several benchmark examples. The results demonstrate well the efficiency and accuracy of the proposed method.展开更多
Using comparative analysis and logical reasoning methods,in combination with traditional logistics theory and practice,and on the basis of objective demand of modern agricultural development for logistics service,we a...Using comparative analysis and logical reasoning methods,in combination with traditional logistics theory and practice,and on the basis of objective demand of modern agricultural development for logistics service,we analyze features of logistics function.Besides,we discuss functional elements and service contents of agricultural modern logistics.In addition,we explore innovation model of agricultural modern logistics and systematized operation of supply chain.Finally,it is concluded that logistics development shall bring into full play all functional elements and achieve high efficient operation of the system through enhanced management measures.展开更多
In order to establish the sufficient and necessary condition that arbitrarily reliable systems can not be constructed with function elements under interference sources, it is very important to expand set of interferen...In order to establish the sufficient and necessary condition that arbitrarily reliable systems can not be constructed with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of interference sources are raised respectively: interference source possessing real input vectors and constant reliable interference source. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbitrarily reliable systems can not be constructed with the elements effected by above interference sources.展开更多
An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system (FPSO system). Finite water depth Green function and higher-order boundar...An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system (FPSO system). Finite water depth Green function and higher-order boundary ele- ment method are used to solve integral equation. Numeri- cal results about added mass and damping are presented for odd and even mode motions of FPSO. The results show ro- bust convergence in high frequency range and can be used in wave load analysis for FPSO designing and operation.展开更多
In this paper, we define the shared value of an algebroid function and its derivative on its Riemann surface. By considering the relationship between the shared values and the branch points of algebroid functions and ...In this paper, we define the shared value of an algebroid function and its derivative on its Riemann surface. By considering the relationship between the shared values and the branch points of algebroid functions and their derivatives, we obtain some uniqueness theorems of algebroid functions sharing values with their derivatives, which extend 3 IM shared values theorem of nonconstant meromorphic functions and their derivatives obtained by Mues-Steinmetz and Gundersen.展开更多
The main purpose of this paper is to study the problems on the existence of algebraic solutions for some second-order complex differential equations with entire algebraic function element coeifficients. Several theore...The main purpose of this paper is to study the problems on the existence of algebraic solutions for some second-order complex differential equations with entire algebraic function element coeifficients. Several theorems on the existence of solutions are obtained, which perfect the solution theory of linear complex differential equations.展开更多
To reduce computational costs, an improved form of the frequency domain boundary element method(BEM) is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitr...To reduce computational costs, an improved form of the frequency domain boundary element method(BEM) is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitrary orientation. The boundary integral equation(BIE) representation solves the two-dimensional convected Helmholtz equation(CHE) and its fundamental solution, which must satisfy a new Sommerfeld radiation condition(SRC) in the physical space. In order to facilitate conventional formulations, the variables of the advanced form are expressed only in terms of the acoustic pressure as well as its normal and tangential derivatives, and their multiplication operators are based on the convected Green's kernel and its modified derivative. The proposed approach significantly reduces the CPU times of classical computational codes for modeling acoustic domains with arbitrary mean flow. It is validated by a comparison with the analytical solutions for the sound radiation problems of monopole,dipole and quadrupole sources in the presence of a subsonic uniform flow with arbitrary orientation.展开更多
In this paper, we introduce the integration of algebroidal functions on Riemann surfaces for the first time. Some properties of integration are obtained. By giving the defi- nition of residues and integral function el...In this paper, we introduce the integration of algebroidal functions on Riemann surfaces for the first time. Some properties of integration are obtained. By giving the defi- nition of residues and integral function element, we obtain the condition that the integral is independent of path. At last, we prove that the integral of an irreducible algebroidal function is also an irreducible algebroidal function if all the residues at critical points are zeros.展开更多
The discrete scheme called discrete operator difference for differential equations was given. Several difference elements for plate bending problems and plane problems were given. By investigating these elements, the ...The discrete scheme called discrete operator difference for differential equations was given. Several difference elements for plate bending problems and plane problems were given. By investigating these elements, the ability of the discrete forms expressing to the element functions was talked about. In discrete operator difference method, the displacements of the elements can be reproduced exactly in the discrete forms whether the displacements are conforming or not. According to this point, discrete operator difference method is a method with good performance.展开更多
This paper discusses some basic properties of algebroid functions in a subdomain of the complex plane and some similar results (to those in the whole complex plane) and a new situation are showed.
The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era...The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA (Hall et al., 2004). Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly (Jiang et al., 2003).展开更多
The repair and treatment of tumor bone defects is a difficult problem to solve urgently in clinical medicine.After tumor resection,patients are not only faced with a large area of bone defect,but also may have the ris...The repair and treatment of tumor bone defects is a difficult problem to solve urgently in clinical medicine.After tumor resection,patients are not only faced with a large area of bone defect,but also may have the risk of tumor recurrence,which can easily cause huge physical and mental harm to patients.In this study,we successfully designed and constructed an organic/inorganic composite microgel bone powder(S-H-M3%Ce/3%Se)based on cerium(Ce)and selenium(Se)elements co-doped mesoporous bioactive glass(M3%Ce/3%Se),sodium alginate(SA),and recombinant human-like collagen(HLC).The obtained S-H-M3%Ce/3%Se could inhibit the growth of osteoma cells and promote the growth of normal cells,and effectively promote the repair of defect bone.The integration of the“treatment and repair”organic/inorganic composite microgel bone powder provided a new strategy for the treatment of cancerous bone defects.展开更多
Sulfur is an essential functional element in leaves,and it plays important roles in regulating plant growth,development and abiotic stress resistance in natural communities.However,there has been limited information o...Sulfur is an essential functional element in leaves,and it plays important roles in regulating plant growth,development and abiotic stress resistance in natural communities.However,there has been limited information on the spatial variation in leaf sulfur content(LSC)and adaptive characters on a large community scale.Sulfur in leaves of 2207 plant species from 80 widespread ecosystems(31 forests,38 grasslands and 11 deserts)in China was measured.One-way analysis of variance with Duncan’s multiple-range tests were used to evaluate the differences in LSC among different plant growth forms and ecosystems.We fitted the relationships of LSC to spatial and climate factors using regression.Structural equation modeling analysis and phylogenetic analysis helped us further explore the main factors of LSC variation.LSC ranged from 0.15 to 48.64 g·kg^(-1),with an average of 2.13±0.04 g·kg^(-1) at the community scale in China.We observed significant spatial variation in LSC among different ecosystems and taxa.Overall,LSC was higher in arid areas and herbs.Furthermore,higher LSC was observed under environments of drought,low temperatures and intense ultraviolet radiation.Temperature,precipitation,radiation,soil sulfur content and aridity jointly regulated LSC,explaining 79%of the spatial variation.However,LSC was not significantly related to phylogeny.Our results demonstrate that LSC plays an important role in plant adaptations to extreme environments and further extend our understanding of the biological function of sulfur from the organ to the community level.These findings highlight the importance of sulfur metabolism for our understanding of the impact of global climate change on plants.展开更多
The boundary element method(BEM) is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required...The boundary element method(BEM) is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required calculations and storage increase rapidly with the increase of the structure scale. Thus, an accelerated method with a low storage is desirable for the wave interaction with a very large structure. A systematic review is given in this paper for the BEM for solving the problem of the wave interaction with a large scale structure. Various integral equations are derived based on different Green functions, the advantages and disadvantages of different discretization schemes of the integral equations by the constant panels, the higher order elements, and the spline functions are discussed. For the higher order element discretization method, the special concerns are given to the numerical calculations of the single-layer potential, the double layer potential and the solid angle coefficients. For a large scale computation problem such as the wave interaction with a very large structure or a large number of bodies, the BEMs with the FMM and p FFT accelerations are discussed, respectively, including the principles of the FMM and the p FFT, and their implementations in various integral equations with different Green functions. Finally, some potential applications of the acceleration methods for problems with large scale computations in the ocean and coastal engineering are introduced.展开更多
In this paper, we estimate the constants in the inverse inequalities for the finite ele- ment functions. Furthermore, we obtain the least upper bounds of the constants in inverse inequalities for the low-order finite ...In this paper, we estimate the constants in the inverse inequalities for the finite ele- ment functions. Furthermore, we obtain the least upper bounds of the constants in inverse inequalities for the low-order finite element functions. Such explicit estimates of the con- stants can be used as computable error bounds for the finite element method.展开更多
Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional...Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-Ⅳ elements including silicene, germanene and stanene within the Green's function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene(stanene) has the maximum(minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases(decreases) with impurity concentration in silicene(germanene and stanene) structure.展开更多
文摘This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials (FGMs). First, a Laplace transform approach is used to handle the time variable. Then, a fundamental solution in Laplace space for FGMs is constructed. Next, a hybrid graded element is formulated based on the obtained fundamental solution and a frame field. As a result, the graded properties of FGMs are naturally reflected by using the fundamental solution to interpolate the intra-element field. Further, Stefest's algorithm is employed to convert the results in Laplace space back into the time-space domain. Finally, the performance of the proposed method is assessed by several benchmark examples. The results demonstrate well the efficiency and accuracy of the proposed method.
基金Supported by Youth Fund Project of Weifang University (2010S10)
文摘Using comparative analysis and logical reasoning methods,in combination with traditional logistics theory and practice,and on the basis of objective demand of modern agricultural development for logistics service,we analyze features of logistics function.Besides,we discuss functional elements and service contents of agricultural modern logistics.In addition,we explore innovation model of agricultural modern logistics and systematized operation of supply chain.Finally,it is concluded that logistics development shall bring into full play all functional elements and achieve high efficient operation of the system through enhanced management measures.
基金Tsinghua University Research Foundation(JC2000025)
文摘In order to establish the sufficient and necessary condition that arbitrarily reliable systems can not be constructed with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of interference sources are raised respectively: interference source possessing real input vectors and constant reliable interference source. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbitrarily reliable systems can not be constructed with the elements effected by above interference sources.
基金supported by the Fundamental Research Funds forthe Central Universities (DVT10LK43)the Returned Overseas Chinese Scholars,State Education Ministry (2007[24])
文摘An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system (FPSO system). Finite water depth Green function and higher-order boundary ele- ment method are used to solve integral equation. Numeri- cal results about added mass and damping are presented for odd and even mode motions of FPSO. The results show ro- bust convergence in high frequency range and can be used in wave load analysis for FPSO designing and operation.
基金supported by NSF of China (11209119511171119+1 种基金11101096)the STP of Education Department of Jiangxi Province,China (GJJ12179)
文摘In this paper, we define the shared value of an algebroid function and its derivative on its Riemann surface. By considering the relationship between the shared values and the branch points of algebroid functions and their derivatives, we obtain some uniqueness theorems of algebroid functions sharing values with their derivatives, which extend 3 IM shared values theorem of nonconstant meromorphic functions and their derivatives obtained by Mues-Steinmetz and Gundersen.
基金Supported by Guangdong Natural Science Foundation(2015A030313628,S2012010010376)Training plan for Distinguished Young Teachers in Higher Education of Guangdong(Yqgdufe1405)+1 种基金Guangdong Education Science Planning Project(2014GXJK091,GDJG20142304)the National Natural Science Foundation of China(11301140,11101096)
文摘The main purpose of this paper is to study the problems on the existence of algebraic solutions for some second-order complex differential equations with entire algebraic function element coeifficients. Several theorems on the existence of solutions are obtained, which perfect the solution theory of linear complex differential equations.
基金supported by National Engineering School of Tunis (No.13039.1)
文摘To reduce computational costs, an improved form of the frequency domain boundary element method(BEM) is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitrary orientation. The boundary integral equation(BIE) representation solves the two-dimensional convected Helmholtz equation(CHE) and its fundamental solution, which must satisfy a new Sommerfeld radiation condition(SRC) in the physical space. In order to facilitate conventional formulations, the variables of the advanced form are expressed only in terms of the acoustic pressure as well as its normal and tangential derivatives, and their multiplication operators are based on the convected Green's kernel and its modified derivative. The proposed approach significantly reduces the CPU times of classical computational codes for modeling acoustic domains with arbitrary mean flow. It is validated by a comparison with the analytical solutions for the sound radiation problems of monopole,dipole and quadrupole sources in the presence of a subsonic uniform flow with arbitrary orientation.
基金supported by the National Natural Science Foundation of China(11501127)Guangdong Natural Science Foundation(2015A030313628)+1 种基金the Training Plan for Outstanding Young Teachers in Higher Education of Guangdong(Yqgdufe1405)the Open Fund of the National Higher Education Quality Monitoring Data Center(Guangzhou)(G1613)
文摘In this paper, we introduce the integration of algebroidal functions on Riemann surfaces for the first time. Some properties of integration are obtained. By giving the defi- nition of residues and integral function element, we obtain the condition that the integral is independent of path. At last, we prove that the integral of an irreducible algebroidal function is also an irreducible algebroidal function if all the residues at critical points are zeros.
文摘The discrete scheme called discrete operator difference for differential equations was given. Several difference elements for plate bending problems and plane problems were given. By investigating these elements, the ability of the discrete forms expressing to the element functions was talked about. In discrete operator difference method, the displacements of the elements can be reproduced exactly in the discrete forms whether the displacements are conforming or not. According to this point, discrete operator difference method is a method with good performance.
文摘This paper discusses some basic properties of algebroid functions in a subdomain of the complex plane and some similar results (to those in the whole complex plane) and a new situation are showed.
基金supported by the grants from the National Natural Science Foundation of China(Nos.31576124,31071382 and 30771210)the National Basic Research Program of China(973 Program,Nos.2010CB125904 and 2013CBA01405)
文摘The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA (Hall et al., 2004). Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly (Jiang et al., 2003).
基金This work was supported by the National Natural Science Foundation of China(Nos.22078265,21908179,and 21838009)the National key Research and development program of China(No.2021YFC2103900)the Shaanxi Provincial Science Foundation(Nos.2017SF-201 and 218JQ2052).
文摘The repair and treatment of tumor bone defects is a difficult problem to solve urgently in clinical medicine.After tumor resection,patients are not only faced with a large area of bone defect,but also may have the risk of tumor recurrence,which can easily cause huge physical and mental harm to patients.In this study,we successfully designed and constructed an organic/inorganic composite microgel bone powder(S-H-M3%Ce/3%Se)based on cerium(Ce)and selenium(Se)elements co-doped mesoporous bioactive glass(M3%Ce/3%Se),sodium alginate(SA),and recombinant human-like collagen(HLC).The obtained S-H-M3%Ce/3%Se could inhibit the growth of osteoma cells and promote the growth of normal cells,and effectively promote the repair of defect bone.The integration of the“treatment and repair”organic/inorganic composite microgel bone powder provided a new strategy for the treatment of cancerous bone defects.
基金supported by the Natural Science Foundation of China(31988102,31872690)National Key R&D Program of China(2017YFA0604803).
文摘Sulfur is an essential functional element in leaves,and it plays important roles in regulating plant growth,development and abiotic stress resistance in natural communities.However,there has been limited information on the spatial variation in leaf sulfur content(LSC)and adaptive characters on a large community scale.Sulfur in leaves of 2207 plant species from 80 widespread ecosystems(31 forests,38 grasslands and 11 deserts)in China was measured.One-way analysis of variance with Duncan’s multiple-range tests were used to evaluate the differences in LSC among different plant growth forms and ecosystems.We fitted the relationships of LSC to spatial and climate factors using regression.Structural equation modeling analysis and phylogenetic analysis helped us further explore the main factors of LSC variation.LSC ranged from 0.15 to 48.64 g·kg^(-1),with an average of 2.13±0.04 g·kg^(-1) at the community scale in China.We observed significant spatial variation in LSC among different ecosystems and taxa.Overall,LSC was higher in arid areas and herbs.Furthermore,higher LSC was observed under environments of drought,low temperatures and intense ultraviolet radiation.Temperature,precipitation,radiation,soil sulfur content and aridity jointly regulated LSC,explaining 79%of the spatial variation.However,LSC was not significantly related to phylogeny.Our results demonstrate that LSC plays an important role in plant adaptations to extreme environments and further extend our understanding of the biological function of sulfur from the organ to the community level.These findings highlight the importance of sulfur metabolism for our understanding of the impact of global climate change on plants.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51379032,51490672 and 51479026)
文摘The boundary element method(BEM) is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required calculations and storage increase rapidly with the increase of the structure scale. Thus, an accelerated method with a low storage is desirable for the wave interaction with a very large structure. A systematic review is given in this paper for the BEM for solving the problem of the wave interaction with a large scale structure. Various integral equations are derived based on different Green functions, the advantages and disadvantages of different discretization schemes of the integral equations by the constant panels, the higher order elements, and the spline functions are discussed. For the higher order element discretization method, the special concerns are given to the numerical calculations of the single-layer potential, the double layer potential and the solid angle coefficients. For a large scale computation problem such as the wave interaction with a very large structure or a large number of bodies, the BEMs with the FMM and p FFT accelerations are discussed, respectively, including the principles of the FMM and the p FFT, and their implementations in various integral equations with different Green functions. Finally, some potential applications of the acceleration methods for problems with large scale computations in the ocean and coastal engineering are introduced.
基金Acknowledgments. This work is supported by the National Natural Science Foundation of China (No. 11071226).
文摘In this paper, we estimate the constants in the inverse inequalities for the finite ele- ment functions. Furthermore, we obtain the least upper bounds of the constants in inverse inequalities for the low-order finite element functions. Such explicit estimates of the con- stants can be used as computable error bounds for the finite element method.
文摘Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-Ⅳ elements including silicene, germanene and stanene within the Green's function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene(stanene) has the maximum(minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases(decreases) with impurity concentration in silicene(germanene and stanene) structure.