递归方法和团簇磁性的计算

介绍了如何应用递归方法将哈密顿矩阵三对角化,从而求得局域态密度 ,并以计算铑团簇的磁矩为例,说明了递归方法在研究团簇的电子结构方面的应用。     

Bounded Immunity and Btt-Reductions

We define and study a new notion called k-immunity that lies between immunity and hyperimmunity in strength. Our interest in k-immunity is justified by the result that θ does not k-tt reduce to a k-immune set, which improves a previous result by Kobzev [7]. We apply the result to show that Φ′ does not btt-reduce to MIN, the set of minimal programs. Other applications include the set of Kolmogorov random strings, and retraceable and regressive sets. We also give a new characterization of effectively simple sets and show that simple sets are not btt-cuppable.     

Recursively Enumerable Equivalence Relations Modulo Finite Differences

We investigate the upper semilattice Eq* of recursively enumerable equivalence relations modulo finite differences. Several natural subclasses are shown to be first-order definable in Eq*. Building on this we define a copy of the structure of recursively enumerable many-one degrees in Eq*, thereby showing that Th(Eq*) has the same computational complexity as the true first-order arithmetic. Mathematics Subject Classification: 03D25, 03D15, 03D35.     

Study of disorder-order transitions in FexAl1−x binary alloys using the augmented space recursion based orbital peeling technique

In this communication we propose a method for the study of disorder-order transitions in Fe_xAl_1−x binary alloys. We turn to our earlier development [1] of a combination of the recursion method introduced by Haydock et al. [2] and our augmented space approach [3] with the orbital peeling technique proposed by Burke [4] to determine the small energy differences required in obtaining the pair energies which go as input to the generalized perturbation technique [5] of studying disorder-order transitions.     

Recursive formulation of the relativistic law of superposition of multiple collinear velocities

We study the recursive formulation of the law of superposition of multiple collinear velocities. We start with the non-linear equation, transform it into two linear coupled difference equations with variable cofficients, and then decouple these latter equations. The coupled difference equations are solved by three different, but interrelated, methods: (i) via the graph theoretic discrete path approach, (ii) by using the general closed form solution of two coupled first order difference equations with variable coefficients, and (iii) in terms of the symmetric functions via the pochhammers of 2 × 2 non-autonomous matrices. The solutions of the decoupled equations are factorial polynomials.     

The study and application of a new filtering method on electronic speckle pattern interferometric fringe

It is important for the study of digital image processing to remove noises and enhance images because of various noises in images. The article is concerned with the recursive algorithm-filtering technique, which is capable of effectively removing noise and rapidly leading to a continuous gray-level distribution of a random image. By applying the method on speckle images of defects of rubber material, it is shown that this technique is the most effective and speedy method for the filtering of ESPI fringe patterns. Comparing the images before and after filtering, we can see the advantages of the novel technique clearly. It can increase the accuracy of measurement both in phase measurement and in quantitative evaluations of defects.     

Compatibility of symplectic structures adapted to noncommutatively integrable systems

It is known that any integrable, possibly degenerate, Hamiltonian system is Hamiltonian relative to many different symplectic structures; under certain hypotheses, the ‘semi-local’ structure of these symplectic forms, written in local coordinates of action-angle type, is also known. The purpose of this paper is to characterize from the point of view of symplectic geometry the family of all these structures. The approach is based on the geometry of noncommutatively integrable systems and extends a recent treatment of the nondegenerate case by Bogoyavlenskij. Degenerate systems are comparatively richer in symplectic structures than nondegenerate ones and this has the counterpart that the bi-Hamiltonian property alone does not imply integrability. However, integrability is still guaranteed if a system is Hamiltonian with respect to three suitable symplectic structures. Moreover, some of the properties of recursion operators are retained.     

无序二元合金(Ni_xCu_(1-x))表面CO吸附及对表面偏析的影响

根据计算机编程构造出了存在和不存在表面偏析的无序二元合金NixCu1 -x(x =0 4 )的原子集团模型 ,然后按覆盖度θ=0 5 ,构造出了CO表面吸附的模型 ,应用Recursion方法计算了CO在NixCu1 -x(存在偏析和不存在偏析时 )合金表面不同位置 (顶位和芯位 )吸附的电子结构 .由此得出 :1 )CO在顶位吸附时较稳定 ;2 )CO吸附使合金表面态密度峰降低 ,带宽加宽 ,使d轨道的局域性变弱 ;3)CO的吸附抑制了Cu在表面富集 ,从电子层次上解释了CO吸附于NixCu1 -x对合金表面偏析的影响机理