压电材料平面应力状态的直线裂纹问题一般解

研究了含直线裂纹系的压电材料平面应力问题单个裂纹和双裂纹问题的封闭解答表明，在裂纹尖端，应力、电场强度和电位移有１／２阶的奇异性并与前人结果比较了产生电场奇异性的物理因素     

重庆“朝天扬帆”钢结构工程风振研究

“朝天扬帆”是位于重庆朝天间广场的钢结构雕塑工程,该工程建筑型体复杂、结构布局不规则,通过该雕塑工程缩尺模型的几洞试验,确定其风载计算的体型系数;用时程法计算结构的风振响应,且在模拟作用于结构上的脉动风时程曲线时考虑结构的高度相关性,应用ALGOR93软件对结构进行风振时程分析,并自编程序加以前、后处理。通过对比该结构在脉动风和平均风作用下的杆件内力、节点位移响应,约定结构风振系数,为该雕塑工程抗风设计参数的确定提供理论依据。     

Bifurcation analysis of a diffusive predator–prey system with a herd behavior and quadratic mortality

In this paper, a diffusive predator–prey system, in which the prey species exhibits herd behavior and the predator species with quadratic mortality, has been studied. The stability of positive constant equilibrium, Hopf bifurcations, and diffusion‐driven Turing instability are investigated under the Neumann boundary condition. The explicit condition for the occurrence of the diffusion‐driven Turing instability is derived, which is determined by the relationship of the diffusion rates of two species. The formulas determining the direction and the stability of Hopf bifurcations depending on the parameters of the system are derived. Finally, numerical simulations are carried out to verify and extend the theoretical results and show the existence of spatially homogeneous periodic solutions and nonconstant steady states. Copyright © 2014 John Wiley & Sons, Ltd.     

A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma北大核心CSCD

Tadalafil( TAD)and dapoxetine HCl( DAP)are recently co-formulated and both show native fluo-rescence. Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chroma-tographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard( IS). Separation was achieved using isocratic elution within 7. 0 min on C18 column and acetonitrile-0. 15% triethylamine( 40∶60,v/v;pH 4)as a mobile phase. The flow rate was 1. 0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm. The linear ranges from 0. 01 to 30. 00 μg/mL for each drug with the limits of detection of 4. 20 and 7. 20 ng/mL for TAD and DAP,respectively. The method was validated in accordance to the International Conference on Harmonization( ICH)guidelines and was successful-ly applied to spiked human plasma with mean recoveries of 98. 17% and 98. 83% for TAD and DAP respectively.     

Amenability properties of Banach algebra valued continuous functions

Let X be a compact Hausdorff space and A   a Banach algebra. We investigate amenability properties of the algebra C(X,A)$C(X,A)$ of all A  -valued continuous functions. We show that C(X,A)$C(X,A)$ has a bounded approximate diagonal if and only if A has a bounded approximate diagonal; if A   has a compactly central approximate diagonal (unbounded) then C(X,A)$C(X,A)$ has a compactly approximate diagonal. Weak amenability of C(X,A)$C(X,A)$ for commutative A is also considered.     

Cohomological relation between Jacobi forms and skew‐holomorphic Jacobi forms

Eichler and Zagier developed a theory of Jacobi forms to understand and extend Maass' work on the Saito‐Kurokawa conjecture. Later Skoruppa introduced skew‐holomorphic Jacobi forms, which play an important role in understanding liftings of modular forms and Jacobi forms. In this paper, we explain a relation between Jacobi forms and skew‐holomorphic Jacobi forms in terms of a group cohomology. More precisely, we introduce an isomorphism from the direct sum of the space of Jacobi cusp forms on and the space of skew‐holomorphic Jacobi cusp forms on with the same half‐integral weight to the Eichler cohomology group of with a coefficient module coming from polynomials.     

Associating divisors with quadratic differentials on Klein surfaces

We extend the notion and basic properties of quadratic differential divisors to a Klein surface, using the corresponding form’s divisors from the double cover of the Klein surface.     

水下任意刚性散射体对Bessel波的散射特性分析

本文利用Bessel波的谐波展开式, 采用T矩阵方法的推导思路, 建立了水下任意刚性散射体在Bessel波照射下的声散射场计算公式. 以水下刚性椭球体和两端附连半球的刚性圆柱体为例, 计算了在不同波锥角β 下的反向散射形态函数, 同时, 依据镜反射波和绕行波的干涉物理模型, 给出了预报Bessel波照射下的反向散射形态函数峰峰间隔值的计算模型. 仿真结果表明本文提出的Bessel波照射下反向散射形态函数峰峰间隔值预报方法是准确有效的, 同时也说明, 本文建立的基于T矩阵法计算水下任意刚性散射体在Bessel波束下的声散射场方法是有效的, 这拓展了T矩阵法的应用领域.     

Coxeter’s frieze patterns and discretization of the Virasoro orbit

We show that the space of classical Coxeter’s frieze patterns can be viewed as a discrete version of a coadjoint orbit of the Virasoro algebra. The canonical (cluster) (pre)symplectic form on the space of frieze patterns is a discretization of Kirillov’s symplectic form. We relate a continuous version of frieze patterns to conformal metrics of constant curvature in dimension 2.     

Analysis on Fractal Objects

Irregular objects are often modeled by fractals sets. In order to formulate partial differential equations on these nowhere differentiable sets the development of a “new analysis” is necessary. With the help of the model case of the Sierpinski gasket the definition of energy forms and Laplacians on self-similar finitely ramified fractals is explained. Moreover, some results for certain classes of non-self-similar fractals are presented. 2000 Math. Subj. Class.: Primary 28A80, 35J15; Secondary 31C25, 35P05