Covering maps that are not compositions of covering maps of lesser order

In 1995 J.W. Heath asked which exactly -to-one maps are compositions of exactly -to-one maps with . This paper deals with compositions of covering maps. Exactly -to-one covering maps on locally arcwise connected continua that are not factorable into covering maps of order are constructed for all 's, and characterized in algebraic terms (fundamental groups). They are not proper compositions of exactly -to-one maps, open maps, or locally one-to-one maps.     

单位球上不同Hardy空间之间的复合算子

本文研究了ＣＮ中单位球Ｂ上不同Ｈａｒｄｙ空间之间的复合算子,引入了η－Ｃａｒｌｅｓｏｎ测度,利用它作为工具给出了有界的或紧的复合算子Ｃ■： Ｈｐ（Ｂ） → Ｈｑ（Ｂ）的特征．     

凸对策核仁的非空性及合成凸对策核仁的单调性

本文给出了核仁与核及最小核心之间的关系 ,且证明了凸对策核仁的存在性和唯一性 ,证明了凸对策的合成对策仍是凸对策 .最后 ,我们讨论了合成凸对策的核仁不满足单调性 .     

Analysis of Effective Composition of Hippophae Rhamnoides L.

IntroductionH ippophae Rhamnoides L. is a kind ofdeciduous arbor or bush,which is indispensablewoods in windy and dusty as well as arid areas,and itis an idealized green protective screen due toits advantages of higher survive rate and less plantdiseases and insectpests and the effects of acting aswind- break and sand- fixation,conserving waterand improving the soil.H ippophae Rhamnoides L.shows preciously nutritive value and medical value,contains many kinds of vitamin,proteins,amino-acids,t…     

Composition Operators on the Bloch Space of Several Complex Variables

Abstract In this paper, we study the boundedness and compactness of composition operator C _φ on the Bloch space β(Ω), Ω being a bounded homogeneous domain. For Ω = B _n, we give the necessary and sufficient conditions for a composition operator C _φ to be compact on β(B _n) or β ₀(B _n). Supported by the National Natural Science Foundation and the National Education Committee Doctoral Foundation     

The extended IEM mixing model in the framework of the composition PDF approach: applications to diesel spray combustion

A steady, two-dimensional corner flame is established when fuel and oxidizer enter the reaction zone in mutually perpendicular directions. A model problem in which the velocity fields are linear functions of spatial position is utilized to study the resulting flame. The flame structure is comprised of a diffusion flame surrounded on either side by fuel-rich and fuel-lean partially premixed laminar flames, similar to, but distinct from, triple flames. Using suitable coordinate transformations and change of variables, the governing equations in the thermodiffusive approximation are recast into a form akin to classical triple flames, with the strain rate appearing as the eigenvalue. A new exact integral representation of the solution to the mixture fraction equation is then utilized and high activation energy asymptotics are applied to solve approximately for the resulting flame shape, the imposed strain rate and, most significantly, the position of flame stabilization. This theoretically predicted flame is computed numerically, and comparisons are made between theory and computation.     

The essential norm of a composition operator on the bergman space of the unit ball

In this paper, we express the essential norm of a composition operator on Bergman spaces of the unit ball in terms of an asymptotic upper bound of a quantity involving the pull-back measure induced by the inducing map. The result could be generalized to convex domains of finite type and to the weighted situation.     

低地应力区碎裂结构围岩基本特征研究

以某市引水工程地下洞室围岩为例 ,采取试验样品若干件 ,分别做了围岩的平均化学成分与百分含量衍射以及电镜扫描分析 ,并得到了相应的结果。在此基础上 ,从成分和微观结构两方面入手 ,总结出低地应力区碎裂结构围岩组成与显微结构方面的特征和变化规律 ,初步探讨了低地应力区碎裂结构围岩微观变形特征 ,这为进一步研究低地应力区围岩宏观变形破坏及其稳定性等方面 ,将会起到重要的理论指导作用