BLLac天体研究简介

本文对BLLac天体的研究现状，目前天体物理界热衷的问题：尘埃问题，宁静问题、发射线问题、BLLac天体与OVV／HPQ关系问题，及处理BLLac天体的流行方案作一个介绍。     

对F.& M.Riesz定理和圆盘代数的极大理想定理的推广

本文将F.& M.Riesz定理和圆盘代数的极大理想定理分别推广到向量测度和向量值函数。     

A PTAS for a disc covering problem using width-bounded separators

In this paper, we study the following disc covering problem: Given a set of discs of various radii on the plane and centers on the grid points, find a subset of discs to maximize the area covered by exactly one disc. This problem originates from the application in digital halftoning, with the best known approximation factor being 5.83 (Asano et al., 2004). We show that if their radii are between two positive constants, then there exists a polynomial time approximation scheme. Our techniques are based on the width-bounded geometric separator recently developed in Fu and Wang (2004), Fu (2006). This research is supported by Louisiana Board of Regents fund under contract number LEQSF(2004-07)-RD-A-35.     

对电子期刊的理性思考

根据电子期刊的发展概况,理性地分析了电子期刊相对于印刷型期刊的优势和不足,论证了电子型期刊与印刷型期刊长期并存的观点。