关于面积平均p叶函数（Ⅱ）

假设ｆ（ｚ）＝ｚ＾ｐ（１＋Σ＾∞ｎ＝１ａｎ＾ｚ＾ｎｋ）是△＝｛｜ｚ｜＜１｝内面积平均ｐ叶的（如果必要，△＝｛｜ｚ｜＜１｝＼（－１，０］）。本文的主要结论是：（１）如果设Ｍ（ｒ）＝ｍａｘ｜ｆ（ｚ）｜，则（１－ｒ）２ｐ／ｋＭ（ｒ）→αｋ≤１（ｒ→１），αｋ＝１的充要条件是ｆ（ｚ）＝ｚ＾ｐ（１－ｘｚ＾ｋ）＾－２ｐ／ｋ，｜ｘ｜＝１。进一步，如果１≤ｋ＜４ｐ，我们有｜ａｎ｜ｎ＾１－２ｐ／ｋ→αｋГ（２ｐ／ｋ     

关于面积平均P叶函数的最大增长方向

本文研究了具有最大增长方向的面积平均Ｐ叶函数的渐近性质和最大增长方向的唯一性，推广并改进了Ｉ．Ｍ．Ｍｉｌｉｎ的一个结果。     

亚纯p叶凸象函数的子类

本文引进单位圆盘内亚纯ｐ叶凸函数的新子类Ｃ（ｎ,ｐ,Ａ,Ｂ）和Ｋ（ｎ,ｐ,Ａ,Ｂ）,分别研究其包含关系与类中函数的积分变换等性质．     

关于面积平均p叶函数（Ⅰ）

Ｌｅｂｅｄｅｖ－Ｍｉｌｉｎ方法是研究单叶函数的强有力的方法，本文建立了几个不等式，使得用这个方法来研究面积平均ｐ叶函数成为可能．本文还给出一个应用一－ＨａｍｉＩｔｏｎ猜测的证明。利用上述不等式和方法我们还能得到一些有趣的结果，这将另文讨论。     

一类不能作为自同构群的有限群

本文证明了阶小于ｐ９的有限交换ｐ－群不能作为有限群的自同构群，从而推进了ＭａｃＨａｌｅ的结果．     

关于p—局部群系的临界性问题

本文利用文献〔１〕定义的ｆ－超中心，给出了ｐ－局部群系临界性问题的结构。利用该结构将文献〔２〕的一些结果推广到一般的ｐ－局部群系ｆｐ上，从而使Ｉｔｏ定理＾〔３〕和Ｂｕｃｋｌｅｙ定理＾〔３〕成为本文定理２．２和定理２．３的特殊情况。本文还利用Ｓ－拟正规的概念〔３〕，将Ｉｔｏ定理和Ｂｕｃｋｌｅｙ定理推广到一般的ｐ－局部群系ｆｐ上。     

关于p－超可解群的若干充分条件

关于ｐ－超可解群的若干充分条件王品超，李文祥（山东曲阜师范大学数学系，２７３１６５）（山东滨州师专数学系，２５６６０４）关键词Ｐ－超可解群，ｐ－ｓｙｌｏｗ子群．分类号ＡＭＳ（１９９１）２０Ｄ２０／ＣＣＬＯ１５２本文定理１推广了［１］（ｐ８８）中定理８...     

沿曲线的极大算子和Hilbert变换的L^p有界性

本文沿Ｒ＾ｎ中曲线的极大算子Ｍ和Ｈｉｌｂｅｒｔ变换Ｈ的Ｌ＾ｐ有界性。对一类凸曲线，证明了Ｍ和Ｈ都是Ｌ＾ｐ（Ｒ＾ｎ）上的有界算子，ｐ＞１／     

映射Fp：X→‖AXB—C‖p^p的临界点的特征

对于Ｈｉｌｂｅｒｔ空间有界线性算子Ａ、Ｂ、Ｃ,考虑了当Ａ有一个广义逆Ａ＾－使得（ＡＡ＾－）＾＊＝ＡＡ＾－,Ｂ有一个广义逆Ｂ＾－Ｔ使得（Ｂ＾－Ｂ）＾＊＝Ｂ＾－Ｂ时,映射Ｆｐ：Ｘ→‖ＡＸＢ－Ｃ‖ｐ＾ｐ临界点的特征的一般形式（１〈ｐ〈∞）,推广了Ｐ．Ｊ．Ｍａｈｅｒ的关于ｐ＝２时的结果,并指出该定理可推广到多个算子的情形。     

几何造型的有理p-细分法

本文提出一类细分法——有理ｐ－细分法．该方法能够生成计算机辅助几何设计中常用的有理多项式曲线、曲面，增加了自由度，扩展了表示对象范围，一定程度上推广和完善了Ｃａｖａｒｅｔａ，Ｄａｈｍｅｎ，Ｍｉｃｈｅｌｉ等１９８９年和１９９３年的有关结果．     

关于p叶近于凸性的充分条件

Let Ap(n)(p, n∈N={1,2,...}) denote the class of functions of the form f(z)=zp+ap+nzp+n+... which are analytic in the unit disc E={z:|z|＜1}. By using the method of differential subordinations we give some sufficient conditions for a function f(z)∈Ap(n) to be a certain subclass Rp(n,k) of p-valently close-to-convexity functions.     

与Dziok-Srivastava算子相关的正系数亚纯多叶函数类

利用Dziok-Srivastava算子定义了单位圆盘内以原点为极点的具有正系数的p叶亚纯函数的子类Wp+,q,s(α1,α),考察它们的各种性质,并将解析函数的邻域概念运用于此亚纯多叶函数类.     

Active control of secondary resonances piezoelectric sandwich beams

Secondary resonances of piezoelectric/elastic/piezoelectric sandwich beams submitted to active control are studied in this paper. The proportional and derivative nonlinear potential feedback controls via piezoelectric sensor and actuator layers are used. The dynamics of the beam is modelled by a highly nonlinear ordinary-differential equation. The method of multiple scales is applied and approximate solutions are obtained for hard excitations. Analytical frequency and phase-amplitude relationships as well as the time response are explicitly given for various super- and subharmonic resonances. Static and dynamic stability criteria are elaborated and critical displacement and excitation amplitudes associated to the resulting unstable zones are analytically given. The feedback parameters effects on the subharmonic and superharmonic resonances and on their stability are investigated.     

Boundary-Value Problems of the Theory of Thin and Nonthin Orthotropic Shells with Account of Nonlinearly Elastic Properties and Low Shear Rigidity of Composite Materials

The basic geometric and physical relations and resolving equations of the theory of thin and nonthin orthotropic composite shells with account of nonlinear properties and low shear rigidity of their materials are presented. They are derived based on two theories, namely the theory of anisotropic shells employing the Timoshenko or Kirchhoff-Love hypothesis and the nonlinear theory of elasticity and plasticity of anisotropic media in combination with the Lagrange variational principle. The procedure and algorithm for the numerical solution of nonlinear (linear) problems are based on the method of successive approximations, the difference-variational method, and the Lagrange multiplier method. Calculations of the stress-strain state for a spherical shell with a circular opening loaded with internal pressure are presented. The effect of transverse shear strains and physical nonlinearity of the material on the distribution of maximum deflections and circumferential stresses in the shell, obtained according to two variants of the shell theories, is studied. A comparison of the results of the problem solution in linear and nonlinear statements with and without account of the shell shear strains is given. The numerical data obtained for thin and nonthin (medium thick) composite shells are analyzed.     

Effects of permeability and viscosity in linear polymeric gels

We propose and analyze a mathematical model of the mechanics of gels, consisting of the laws of balance of mass and linear momentum of the polymer and liquid components of the gel. We consider a gel to be an immiscible and incompressible mixture of a nonlinearly elastic polymer and a fluid. The problems that we study are motivated by predictions of the life cycle of body‐implantable medical devices. Scaling arguments suggest neglecting inertia terms, and therefore, we consider the quasi‐static approximation to the dynamics. We focus on the linearized system about stress‐free states, uniform expansions, and compressions and derive sufficient conditions for the solvability of the time‐dependent problems. These turn out to be conditions that guarantee local stability of the equilibrium solutions. We also consider non‐stress free equilibria and states with residual stress and derive an energy law for the corresponding time‐dependent system. The conditions that guarantee stability of solutions provide a selection criteria of the material parameters of devices. The boundary conditions that we consider are of two types, displacement‐traction and permeability of the gel surface to the fluid. We address the cases of viscous and inviscid solvent, assume Newtonian dissipation for the polymer component, and establish existence of weak solutions for the different boundary permeability conditions and viscosity assumptions. We present two‐dimensional, finite element numerical simulations to study stress concentration on edges, this being the precursor to debonding of the gel from its substrate. Copyright © 2015 John Wiley & Sons, Ltd.     

Financial Risk Modelling and Econometric Inference

In finance, the explicit modelling of uncertainty takes on a particularly important role. The values of financial derivatives increase in the return volatility of the underlying security. This notion requires a concept of volatility and hence uncertainty. In addition, the choice between modelling in discrete and continuous time is not arbitrary, since it corresponds to a distinction between incomplete and complete markets, respectively, and this distinction matters for asset pricing, financial risk modelling, and inference. Risk and volatility are closely connected, and implied volatility, volatility forecasting, volatility in term structure models, stochastic volatility, and portfolio analysis are considered and related to a more general interplay between cross-sectional and dynamic aspects in finance. Stocks, bonds, and options are considered and placed in the context of efficiency and separation in inference.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Latroids and their representation by codes over modules

It has been known for some time that there is a connection between linear codes over fields and matroids represented over fields. In fact a generator matrix for a linear code over a field is also a representation of a matroid over that field. There are intimately related operations of deletion, contraction, minors and duality on both the code and the matroid. The weight enumerator of the code is an evaluation of the Tutte polynomial of the matroid, and a standard identity relating the Tutte polynomials of dual matroids gives rise to a MacWilliams identity relating the weight enumerators of dual codes. More recently, codes over rings and modules have been considered, and MacWilliams type identities have been found in certain cases.

In this paper we consider codes over rings and modules with code duality based on a Morita duality of categories of modules. To these we associate latroids, defined here. We generalize notions of deletion, contraction, minors and duality, on both codes and latroids, and examine all natural relations among these.

We define generating functions associated with codes and latroids, and prove identities relating them, generalizing above-mentioned generating functions and identities.

     

计算Hamilton矩阵特征值的一个稳定的有效的保结构的算法

提出了一个稳定的有效的保结构的计算Hamilton矩阵特征值和特征不变子空间的算法,该算法是由SR算法改进变形而得到的。在该算法中,提出了两个策略,一个叫做消失稳策略,另一个称为预处理技术。在消失稳策略中,通过求解减比方程和回溯彻底克服了Bunser Gerstner和Mehrmann提出的SR算法的严重失稳和中断现象的发生,两种策略的实施的代价都非常低。数值算例展示了该算法比其它求解Hamilton矩阵特征问题的算法更有效和可靠。