to the continuum. The peak asymmetry, the width as well as total cusp cross sections are calculated for He++ He collisions and compared with the available experimental data. 1.

This paper describes a practical model for the polarization of Be stars which can be used to estimate roughly the physical parameters for optically thin circumstellar envelopes from broadband UBVRI photopolarimetry data. Analysis of long-term variability in terms of these parameters is a promising approach toward understanding the Be phenomenon. An interesting result from fitting the model to observations of eight Be stars is that all of them may have geometrically thin disks, with opening half-angles on the order of ten degrees or less. This contributes to the growing evidence that most Be disks are geometrically thin. Subject headings: polarization—scattering—techniques:polarimetric—stars: emissionline, Be—stars:winds, outflows—circumstellar matter 1.

Abstract not found

into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories

few material parameters. But it becomes inaccurate for problems in which the detailed atomistic processes affect the macroscopic behavior of the medium, or when the scale of the medium is small enough that the continuum approximation becomes questionable. Such situations are often found in studies

The object of -convergence is the description of the asymptotic behaviour of families of minimum problems, usually depending on some parameters whose nature may be geometric or constitutive, deriving from a discretization argument, an approximation procedure, etc. Since its introduction by De

We consider finite approximations of a topological space M by noncommutative lattices of points. These lattices are structure spaces of noncommutative C ∗-algebras which in turn approximate the algebra C(M) of continuous functions on M. We show how to recover the space M and the algebra C(M) from a

on the idea of continuum approximation, which is valid when the network density is high. Index Terms — Cooperative communications, wireless networks, continuum approximation, performance evaluation, phase transition. I.

A continuum approximation for the excitations of the (1, 1,...,1) interface in the quantum Heisenberg model

www.elsevier.com/locate/jlumin Transport of optical excitations on dendrimers in the continuum approximation