‘True’ self-avoiding walks with generalized bond repulsion on ℤ

We consider a nearest-neighbor random walk on , for which the probability of jumping along a bond of the lattice is proportional to exp[–g. (number of previous jumps along that bond) ^k ], withg>0,k(0,1]. After a review of earlier results obtained for the casek=1 we outline the generalizations fork(0,1), obtaining a whole range of anomalous diffusion limits.Dedicated to Oliver Penrose on the occasion of his 65th birthday     

一类具有二虚不变直线的三次系统的极限环与分支

讨论一类具有二虚平行不变直线的三次系统，求出了奇点O(0,0)的焦点量, 证明了δlmn=0 时系统在O外围至多有一个极限环. 利用分支理论给出了分界线环和半稳 定环分支曲线的分支图，进一步说明了系统至多有二个极限环.     

Limit cycles in a general Kolmogorov model

The problem of limit cycles is interesting and significant both in theory and applications. In mathematical ecology, finding models that display a stable limit cycle—an attracting stable self-sustained oscillation, is a primary work.In this paper, a general Kolmogorov system, which includes the Gause-type model (Math. Biosci. 88 (1988) 67), the general predator-prey model (J. Phys. A: Math. Gen. 21 (1988) L685; Math. Biosci. 96 (1989) 47), and many other models (J. Biomath. 15(3) (2001) 266; J. Biomath. 16(2) (2001) 156; J. Math. 21(22) (2001) 145), is studied. The conditions for the existence and uniqueness of limit cycles in this model are proved. Some known results are easily derived as an illustration of our work.     

Non-chromatographic atomic spectrometric methods in speciation analysis: A review

In recent years, knowledge of the different chemical forms of the elements has gained increasing importance. There has been significant progress in methods that hyphenate chromatographic separations with atomic spectrometry. These hyphenated methods can provide the most complete information on the species distribution and even structure. However, they can be lengthy, relatively costly and difficult to bring to the routine. On the other hand, it is important to remember that chromatographic techniques represent only a minor part of the separation procedures available and, in certain cases, the application of basic chemistry to sample treatments can give quantitative information about specific chemical forms. In this sense, non-chromatographic procedures can provide methods that offer sufficient information on the elemental speciation for a series of situations. Moreover, these non-chromatographic strategies can be less time consuming, more cost effective and available, and present competitive limits of detection. Thus, non-chromatographic speciation analysis continues to be a promising research area and has been applied to the development of several methodologies that facilitate this type of analytical approach. In view of their importance, the present work overviews and discusses different non-chromatographic methods as alternatives for the speciation analysis of clinical, environmental and food samples using atomic spectrometry for detection.     

~n上的非初等变换群及其极限集

该文对高维非初等Mobius变换群进行了研究,得到了一些重要性质,给出了几个关于离散准则和代数收敛性的定理.     

Multiplicative calculus and its applications

Two operations, differentiation and integration, are basic in calculus and analysis. In fact, they are the infinitesimal versions of the subtraction and addition operations on numbers, respectively. In the period from 1967 till 1970 Michael Grossman and Robert Katz gave definitions of a new kind of derivative and integral, moving the roles of subtraction and addition to division and multiplication, and thus established a new calculus, called multiplicative calculus. In the present paper our aim is to bring up this calculus to the attention of researchers and demonstrate its usefulness.     

关于Smarandache LCM序列

For any positive integer n,let L(n)=[1,2,…,n] be the least common multiple of the integers from 1 to n.Let k be any positive integer.The main purpose of this paper is to study the asymptotic property of L(nk),and give some interesting relevant results.     

Abel-like differential equations with no periodic solutions

We present various criteria for the non-existence of positive periodic solutions of generalized Abel differential equations with periodic coefficients that can change sign. As an application, we obtain some families of planar vector fields without limit cycles.     

Adaptive variational curve smoothing based on level set method

This paper presents an adaptive method for variational curve smoothing based on level set implementation. A suitable cost functional is minimized via solving the derived Euler–Lagrangian equation, of which the discretization is conducted on unstructured triangular meshes by employing a simple and effective finite volume scheme. Through adaptive refinement of the mesh, the geometry features of the given curve can be well resolved in a cost-effective way. Various numerical experiments demonstrate the effectiveness and efficiency of the proposed approach.     

应用曲面镜成像原理仿真高温超导体磁悬浮力

文章首次探讨了应用曲面镜成像原理 ,对高温超导体悬浮力进行仿真计算 ,并且比较了实验数据与计算结果 ,结果表明了此方法的有效性。文章还讨论了此方法今后的工作方向。