A Unified Symmetry of Mechanical Systems with Variable Mass in Phase Space

In this paper, the definition and the criterion of a unified symmetry of the mechanical system with variable mass in phase space are given. The Noether conserved quantity, the generalized Hojman conserved quantity, and Mei conserved quantity deduced from the unified symmetry are obtained. An example is given to illustrate the application of the results.     

Explicit algebras with the Leibniz–Mellin translation product

A sub‐calculus of the calculus (“algebra”) of all complete conormal symbols arising in the edge pseudodifferential calculus is constructed. This calculus of complete conormal symbols is suitable for constructing sub‐calculi of the general edge pseudodifferential calculus, for which the edge‐degenerate pseudodifferential operators involved map conormal asymptotics of distributions near the edges in a prescribed manner. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A complex variable meshless method for fracture problems

1 Introduction The meshless (or meshfree) method has been a hot topic and the development trend of numerical methods for many science and engineering problems in recent years. Comparing with the conventional numerical methods, such as the finite element method and the boundary element method, the meshless method is an approximation based on nodes, and does not form a mesh to determine the shape function in the domain, in which a problem is to be solved. The meshless method has some advantages …     

A class of multiobjective linear programming model with fuzzy random coefficients

The aim of this paper is to deal with a multiobjective linear programming problem with fuzzy random coefficients. Some crisp equivalent models are presented and a traditional algorithm based on an interactive fuzzy satisfying method is proposed to obtain the decision maker’s satisfying solution. In addition, the technique of fuzzy random simulation is adopted to handle general fuzzy random objective functions and fuzzy random constraints which are usually hard to be converted into their crisp equivalents. Furthermore, combined with the techniques of fuzzy random simulation, a genetic algorithm using the compromise approach is designed for solving a fuzzy random multiobjective programming problem. Finally, illustrative examples are given in order to show the application of the proposed models and algorithms.     

A generalization of Hardy spaces <Emphasis Type="Italic">H</Emphasis><Superscript><Emphasis Type="Italic">p</Emphasis></Superscript> by using atoms

Let X = （X, d,μ） The purpose of this paper is to be a space of homogeneous type in the sense of Coifman and Weiss. generalize the definition of Hardy space H^P（X） and prove that the generalized Hardy spaces have the same property as H^P（X）. Our definition includes a kind of Hardy- Orlicz spaces and a kind of Hardy spaces with variable exponent. The results are new even for the R^n case. Let （X, δ, μ） be the normalized space of （X, d, μ） in the sense of Macias and Segovia. We also study the relations of our function spaces for （X, d, μ） and （X, δ,μ）.     

PERIODIC SOLUTIONS FOR NEUTRAL LINARD EQUATION WITH A STATEMENT-DEPENDENT DEVIATION VARIABLE

Using the theroy of topological degree, the paper studies the periodic solutions to a type of neutral Lienard equation with state-dependent deviation variable. A sufficient condition for the existence of periodic solution is obtained.     

离心压气机部件几何造型方法的研究

叶轮在微型燃气轮机占有很重要的地位.本文采用B样条曲线,对照母型级压气机叶轮的几何参数,通过调整控制点的参数,并且结合数值模拟,对母型级叶轮进行优化,从而完成了对叶轮几何轮廓的设计.在整个过程中,找到了一种快速的建模的方法,大大缩短了设计时间.     

最速反馈控制的不变性

变结构控制对系统模型和扰动具有一定的不变性是众所周知的事实。最速反馈控制是以其开关曲线为滑动曲线的变结构控制。本文用变结构控制理论来讨论修正了的最速反馈控制对一定范围的系统扰动具有完全的不变性,即完全能够抑制一定范围的扰动作用,而且闭环系统的所有轨线,在理论上,都以有限时间到达原点。这就为设计高效非线性反馈提供了一条有效途径,还给出了避免高频颤震来实现最速反馈控制的数字化办法。     

二维变系数线性微分方程组的稳定性

本文讨论了微分方程组(2),运用[2]中的思路和方结推广了[2]中的结果,并给出了微分方程组(1)稳定性的若干充分条件。     

Quasi-measures with image transformations as generalized variables

We introduce an image transformation as a generalization of measurable maps. Structure properties of the image transformation is given. Unique extension of image transformations from solid sets is proven. The multidimensional median and sample median are presented as image transformations, providing a construction suitable for probability theorists.