运用微分方程稳定性理论,讨论了具有常数输入且疾病发生率为非线性的捕食-被捕食模型,给出了系统解的正不变性.根据微分不等式定理,进一步论证了系统解的有界性和各平衡点的存在性,并通过特征多项式,利用R ou th-Hurw itz判据证明了解...运用微分方程稳定性理论,讨论了具有常数输入且疾病发生率为非线性的捕食-被捕食模型,给出了系统解的正不变性.根据微分不等式定理,进一步论证了系统解的有界性和各平衡点的存在性,并通过特征多项式,利用R ou th-Hurw itz判据证明了解的局部渐近稳定性.通过构造适当的Lyapunov函数分析了各平衡点的全局渐近稳定性.展开更多
Due to the current trend towards lightweight design in automotive industry,hollow stepped gear shafts for automobile and its radial forging process are widely investigated.Utilizing coupled finite element thermo-mecha...Due to the current trend towards lightweight design in automotive industry,hollow stepped gear shafts for automobile and its radial forging process are widely investigated.Utilizing coupled finite element thermo-mechanical model,radial forging process of a hollow stepped gear shaft for automobile was simulated.The optimal combination of three process parameters including initial temperature,rotation rate and radial reduction was also selected using orthogonal design method.To examine the strain inhomogeneity of the forging workpiece,the strain inhomogeneity factor was introduced.The results reveal that the maximum effective strain and the minimum effective strain appeared in the outermost and innermost zones of different cross sections for the hollow stepped gear shaft,respectively.Optimal forging parameters are determined as a combination of initial temperature of 780°C,rotation rate of 21°/stroke and radial reduction of 3 mm.展开更多
We prove that any abelian cover over a smooth variety is defined by some cyclic equations. From the defining equations, we compute explicitly the normalization, branch locus, ramification indices, global invariants, a...We prove that any abelian cover over a smooth variety is defined by some cyclic equations. From the defining equations, we compute explicitly the normalization, branch locus, ramification indices, global invariants, and the resolution of singularities. As an application, we construct a new algebraic surface which is the quotient of ball.展开更多
We revisit quantum gravitational contributions to quantum gauge field theories in the gauge condition independent Vilkovisky-DeWitt formalism based on the background field method.With the advantage of Landau-DeWitt ga...We revisit quantum gravitational contributions to quantum gauge field theories in the gauge condition independent Vilkovisky-DeWitt formalism based on the background field method.With the advantage of Landau-DeWitt gauge,we explicitly obtain the gauge condition independent result for the quadratically divergent gravitational corrections to gauge couplings.By employing,in a general way,a scheme-independent regularization method that can preserve both gauge invariance and original divergent behavior of integrals,we show that the resulting gauge coupling is power-law running and asymptotically free.The regularization scheme dependence is clarified by comparing with results obtained by other methods.The loop regularization scheme is found to be applicable for a consistent calculation.展开更多
Sexual isolation resulting from differences in mate choice behaviors is a hallmark of rapidly-speciating lineages. When present, asymmetrical sexual isolation may provide insights into the mechanisms responsible for t...Sexual isolation resulting from differences in mate choice behaviors is a hallmark of rapidly-speciating lineages. When present, asymmetrical sexual isolation may provide insights into the mechanisms responsible for the evolutionary change in mate signaling traits. In particular, Kaneshiro＇s hypothesis suggests that divergence in sexual characters between populations may arise in allopatry when ＇derived＇ founding populations are subject to severe population bottlenecks, accompanied by a relaxation of sexual selection relative to ＇ancestral＇ source populations. In the present study, we tested predictions of asymmetrical sexual isolation between two allopatric species of Hawaiian Laupala crickets, representing ＇ancestral＇ （L. makaio） and ＇derived＇ （L. nigra） taxa. While crickets in this genus are notable for rapid divergence of male courtship songs, these species share similar song types, thus suggesting that patterns of sexual isolation are likely due to other mating cues. Analysis of behavioral responses in conspeci- fic and heterospecific ＇no-choice＇ mating trials revealed pronounced asymmetrical isolation in the direction predicted by Kane- shiro＇s hypothesis, wherein we observed a significant reduction in mating success for crosses involving ＇derived＇ males paired with ＇ancestral＇ females, compared to the reciprocal heterospecific and both conspecific pairings. Further dissection of courtship behaviors suggested this difference did not reflect male mate choice, but rather, marked reduced spermatophore acceptance rates by ＇ancestral＇ females paired with ＇derived＇ males. The results are discussed with respect to founder effect models of speciatiou and the potential role of chemosensory signals in mate choice in these species [Current Zoology 59 （2）： 230-238, 2013].展开更多
The authors first prove a convergence result on the Ka(?)anov method for solving generalnonlinear variational inequalities of the second kind and then apply the Kacanov method tosolve a nonlinear variational inequalit...The authors first prove a convergence result on the Ka(?)anov method for solving generalnonlinear variational inequalities of the second kind and then apply the Kacanov method tosolve a nonlinear variational inequality of the second kind arising in elastoplasticity. In additionto the convergence result, an a posteriori error estimate is shown for the Kacanov iterates. Ineach step of the Ka(?)anov iteration, one has a (linear) variational inequality of the secondkind, which can be solved by using a regularization technique. The Ka(?)anov iteration andthe regularization technique together provide approximations which can be readily computednumerically. An a posteriori error estimate is derived for the combined effect of the Ka(?)anoviteration and the regularization.展开更多
文摘运用微分方程稳定性理论,讨论了具有常数输入且疾病发生率为非线性的捕食-被捕食模型,给出了系统解的正不变性.根据微分不等式定理,进一步论证了系统解的有界性和各平衡点的存在性,并通过特征多项式,利用R ou th-Hurw itz判据证明了解的局部渐近稳定性.通过构造适当的Lyapunov函数分析了各平衡点的全局渐近稳定性.
基金Projects(51774054,51974050)supported by the National Natural Science Foundation of China。
文摘Due to the current trend towards lightweight design in automotive industry,hollow stepped gear shafts for automobile and its radial forging process are widely investigated.Utilizing coupled finite element thermo-mechanical model,radial forging process of a hollow stepped gear shaft for automobile was simulated.The optimal combination of three process parameters including initial temperature,rotation rate and radial reduction was also selected using orthogonal design method.To examine the strain inhomogeneity of the forging workpiece,the strain inhomogeneity factor was introduced.The results reveal that the maximum effective strain and the minimum effective strain appeared in the outermost and innermost zones of different cross sections for the hollow stepped gear shaft,respectively.Optimal forging parameters are determined as a combination of initial temperature of 780°C,rotation rate of 21°/stroke and radial reduction of 3 mm.
基金supported by National Natural Science Foundation of China (Grant No.10731030)the Innovation Program of Shanghai Municipal Education Commission (Grant No. 11ZZ18)
文摘We prove that any abelian cover over a smooth variety is defined by some cyclic equations. From the defining equations, we compute explicitly the normalization, branch locus, ramification indices, global invariants, and the resolution of singularities. As an application, we construct a new algebraic surface which is the quotient of ball.
基金Supported in part by the National Science Foundation of China under Grant Nos. 10821504,10975170the Key Project of Knowledge Innovation Program of Chinese Academy of Science
文摘We revisit quantum gravitational contributions to quantum gauge field theories in the gauge condition independent Vilkovisky-DeWitt formalism based on the background field method.With the advantage of Landau-DeWitt gauge,we explicitly obtain the gauge condition independent result for the quadratically divergent gravitational corrections to gauge couplings.By employing,in a general way,a scheme-independent regularization method that can preserve both gauge invariance and original divergent behavior of integrals,we show that the resulting gauge coupling is power-law running and asymptotically free.The regularization scheme dependence is clarified by comparing with results obtained by other methods.The loop regularization scheme is found to be applicable for a consistent calculation.
文摘Sexual isolation resulting from differences in mate choice behaviors is a hallmark of rapidly-speciating lineages. When present, asymmetrical sexual isolation may provide insights into the mechanisms responsible for the evolutionary change in mate signaling traits. In particular, Kaneshiro＇s hypothesis suggests that divergence in sexual characters between populations may arise in allopatry when ＇derived＇ founding populations are subject to severe population bottlenecks, accompanied by a relaxation of sexual selection relative to ＇ancestral＇ source populations. In the present study, we tested predictions of asymmetrical sexual isolation between two allopatric species of Hawaiian Laupala crickets, representing ＇ancestral＇ （L. makaio） and ＇derived＇ （L. nigra） taxa. While crickets in this genus are notable for rapid divergence of male courtship songs, these species share similar song types, thus suggesting that patterns of sexual isolation are likely due to other mating cues. Analysis of behavioral responses in conspeci- fic and heterospecific ＇no-choice＇ mating trials revealed pronounced asymmetrical isolation in the direction predicted by Kane- shiro＇s hypothesis, wherein we observed a significant reduction in mating success for crosses involving ＇derived＇ males paired with ＇ancestral＇ females, compared to the reciprocal heterospecific and both conspecific pairings. Further dissection of courtship behaviors suggested this difference did not reflect male mate choice, but rather, marked reduced spermatophore acceptance rates by ＇ancestral＇ females paired with ＇derived＇ males. The results are discussed with respect to founder effect models of speciatiou and the potential role of chemosensory signals in mate choice in these species [Current Zoology 59 （2）： 230-238, 2013].
基金Project supported by the ONR grant N00014-90-J-1238
文摘The authors first prove a convergence result on the Ka(?)anov method for solving generalnonlinear variational inequalities of the second kind and then apply the Kacanov method tosolve a nonlinear variational inequality of the second kind arising in elastoplasticity. In additionto the convergence result, an a posteriori error estimate is shown for the Kacanov iterates. Ineach step of the Ka(?)anov iteration, one has a (linear) variational inequality of the secondkind, which can be solved by using a regularization technique. The Ka(?)anov iteration andthe regularization technique together provide approximations which can be readily computednumerically. An a posteriori error estimate is derived for the combined effect of the Ka(?)anoviteration and the regularization.
