试论新世纪地理信息科学的发展

本文重点分析了当前国内外地理信息科学的形成与发展趋势和地理信息科学不断发展的历程 ,提出近期发展的前沿 ,以及当前地理信息产业化面临的一些重要问题。最后提出对地理信息科学发展的意见。     

Canonical theory of perturbations using eccentric anomaly as independent variable

It is shown in this paper how to build a canonical transformation of variables, so that the eccentric anomaly becomes the new independent variable. In the case of eccentric elliptical orbits it changes the equations of motion so, that they can be integrated analytically to any order of approximation comparatively easy.     

On the expansions of intermediate orbit for general planetary theory

Intermediate orbit for general planetary theory is constructed in the form of multivariate Fourier series with numerical coefficients. The structure and efficiency of the derived series are illustrated by giving various statistical properties of the coefficients.The ability of the recently proposed elliptic function approach to compress the Fourier series representing the intermediate orbit is investigated. Our results confirm that when mutual perturbations of a pair of planets are considered the elliptic function approach is quite efficient and allows one to compress the series substantially. However, when perturbations of three or more planets are under study the elliptic function approach does not give any advantages.     

亚毫米波射电天文用超导SIS接收机的研制(英文)

为了研制亚毫米波射电天文用超导SIS(超导 -绝缘体 -超导 )接收机 ,我们重点开展了如下研究 ,1 )Nb超导SIS结在其能隙频率附近的量子混频特性 ,及其结合高能隙超导薄膜 (NbTiN)和高电导率金属薄膜 (Al)分布结阵在 780 - 950GHz频率区间的量子混频特性 ;2 )亚毫米波超导混频器嵌入阻抗的数值和实验表征 ;3)高电流密度小面积Nb超导SIS结的制备和特性表征 ;4)一个 60 0 - 72 0GHz超导SIS混频器的研制和特性表征。本文详细介绍了相关的数值分析和实验测量结果。