SOFTWARE REVIEWS

Electromap World Atlas , Version 1.1. Interactive Population Statistical System , Version 1.0. Jerry W. Wicks and Jose Luiz Pereira de Almeida MATHCAD , Version 2.5. Memory Mate. Micro DEM +, Version 5.21. Peter Guth NCSS – Number Cruncher Statistical System , Version 5.02. Dr. Jerry L. Hintze     

Discrete Virial Theorem

We reexamine the classical virial theorem for bounded orbits of arbitrary autonomous Hamiltonian systems possessing both regular and chaotic orbits. New and useful forms of the virial theorem are obtained for natural Hamiltonian flows of arbitrary dimension. A discrete virial theorem is derived for invariant circles and periodic orbits of natural symplectic maps. A weak and a strong form of the virial theorem are proven for both flows and maps. While the Birkhoff Ergodic Theorem guarantees the existence of the relevant time averages for both regular and chaotic orbits, the convergence is very rapid for the former and extremely slow for the latter. This circumstance leads to a simple and efficient measure of chaoticity. The results are applied to several problems of current physical interest, including the Hénon–Heiles system, weak chaos in the standard map, and a 4D Froeschlé map.     

数字地图无缝连接及漫游的基本方法

针对目前数字地图应用中通常只使用单幅地图，从而在功能上受到一定限制的情况，本文提出实现多幅地图无缝连接并能漫游的设想，说明了实现这种功能的方法。     

GIS-ILA:THE GIS FOR ITALIAN LOGISTICS IN ANTARCTICA

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Methodological considerations of probabilistic seismic hazard mapping

This paper presents a methodological discussion of several issues involved with the development of maps of seismic hazard. The points made are illustrated with worked examples, using Scotland as an illustrative case. The issues treated are divided under three headings: matters relating to the difference between hazard maps and site studies; matters concerned with the technical issues of mapping, and matters relating to the use to which hazard maps will be put. It is concluded that a hazard map cannot be an all-purpose substitute for site-specific studies, owing to the impracticality of ensuring all-round conservatism in a hazard map, and the lower level of detail (more broad-brush approach) in a regional mapping study. Also, since users of a hazard map are not necessarily going to be engineers, consideration should be given to the provision of maps expressed in parameters other than physical measures of ground motion. Intensity is useful here, since it relates to actual earthquake experience and to damage. One can also move to making maps of generic seismic risk even before one has data on the distribution of exposure and vulnerability. Discussion is made of the issue of testing the validity of hazard maps against real experience, with examples. If a map can be shown to accord with real observations, then it can be treated with greater confidence by users.     

中国地壳运动观测网络基准站倾斜固体潮观测中的海潮负荷信号改正问题

利用最新的全球海潮模型（Csr3.0,Fes95.2,Tpxo2,Csr4.0和Scw80)和中国近海海潮资料，基于标准地球模型负荷格林函数，采用Agnew的积分格林函数方法研究了倾斜固体潮观测中的海潮负荷效应。文章计算了中国地壳运动观测网络25个基准站8个主要潮流的倾斜负荷，数值结果说明对某一潮波而言，倾斜负荷振幅达10^-9弧度，沿海地区达10^-8弧度或更多。文章构制了北京和上海等8个主要台站的倾斜负荷随时间变化。     

基于MAPGIS平台的数字气候图集制作方法

尝试应用MAPGIS手段对新疆40年来的气温、积温、降水、蒸发等要素进行了一系列的计算、分析和制图。生成图像、数据可与其它应用系统进行信息交换、输出编辑图文并茂的应用产品。开拓性、探索性地开展气象服务信息化工作。     

应用MAPGIS处理地质、物化探图件

目前MAPGIS地理信息系统软件已在地质行业中广泛应用。本文叙述的是作者在使用该系统进行物化探图件编制过程中的一点体会和经验。     

Zoning patterns in orthopyroxene and garnet in granulites: implications for geothermometry

Compositional maps of orthopyroxene and garnet of contrasting grain size and in contact with different minerals were made from two paragneiss granulites from the Minto terrane of northern Quebec. The compositional maps provide clear evidence of late exchange of Fe/(Fe + Mg) after Ca in garnet and Al in orthopyroxene had been quenched-in. The extent of late Fe-Mg exchange was controlled by neighbouring minerals, with negligible Fe-Mg gradients against plagioclase and quartz, and substantial gradients against exchangeable Fe-Mg minerals. Cores of grains in contact with exchangeable Fe-Mg neighbours are progressively more reset in Fe/(Fe + Mg) as grain size decreases, whereas cores of even small grains surrounded by only plagioclase and quartz are not significantly different in Fe/(Fe + Mg) than cores of the largest grains. Gradients of Ca in garnet and of Al in orthopyroxene in grains of uniform Fe/(Fe + Mg) preserve a high-temperature retrograde history during which intergranular exchange effected compositional uniformity of mineral rims and intragranular Fe-Mg diffusion in garnet and orthopyroxene was rapid enough to homogenize Fe/(Fe + Mg). The transition from efficient intergranular exchange at relatively high temperatures to local Fe-Mg exchange at lower temperatures may have been controlled by loss of an intergranular exchange medium in the rock, possibly an internally generated dehydration melt phase. Implications for geothermometry of granulites include the following (numerical values are particular to this study): (1) core compositions of garnet and orthopyroxene grains in contact with exchangeable neighbours may be reset in Fe/(Fe + Mg) relative to the most refractory compositions by an amount equivalent to 120d? C; (2) Fe-Mg exchange thermometry using even the most refractory Fe/(Fe + Mg) compositions may not record peak granulite conditions, possibly recording instead the temperature at which an intergranular exchange medium was lost from the rock; and (3) temperature-sensitive net transfer equilibria involving Al solubility in orthopyroxene yield temperatures up to 150d? C higher than maximum Fe-Mg exchange temperatures, even in grains with flat Fe/(Fe - Mg) compositional profiles, making them a better means of estimating peak granulite temperatures than Fe-Mg exchange thermometry.     

Learning Spatial Information from Maps: Can Orientation-Specificity Be Overcome?*

Maps that facilitate learning and navigating through an environment will influence the form and content of cognitive representations developed of that environment. Cognitive representations derived from maps have been demonstrated to exhibit orientation-specificity, a bias toward the orientation at which the map was studied, while cognitive representations derived directly from the environment appear to be orientation-free. An experiment was conducted to test the hypothesis that multi-orientation map presentation can eliminate the usual orientation-specificity. Results support the hypothesis but suggest that elimination of orientation-specificity will come at the cost of decreased accuracy in the cognitive representation obtained and/or slower access to the stored information.