Forced secondary resonances at the 3 : 1 commensurability

For the 3 : 1 Jovian resonance problem, the time scales of the two degrees of freedom of the resonant Hamiltonian are well-separated [5]. With the adiabatic approximation, the solution for the fast oscillations can be found in terms of the slowly varying variables. Thus the rapidly oscillating terms in the slow oscillation equations can be treated as forced terms. We refer to the resonance between the forcing and intrinsic frequencies as a forced secondary one in this paper. We discuss the forced secondary resonances in asteroidal motion at the 3 : 1 commensurability by using Wisdom's method. The results show that the orbits situated originally near the resonance will leave the neighbourhood of resonance and tend to the separatrices and critical points for different energies, respectively. We have not found any stochastic web as expected in this case. Moreover, we study the problem of validity on the approximation of a system.The Project Supported by the National Natural Science Foundation of China.     

Virtual Field Geologic Trip System

Virtual Field Geologic Trip System (VFGTS) constructed by the technique of visualization can efficiently present geologic field information and widely used in the field of geologic education. This paper introduces the developing thinking of VFGTS and discusses the main implement processes. Building VFGTS mainly includes systemically gathering of field geological data, the building of virtual geological world, and displaying of virtual geologic world and human-computer interaction.     

用ASP.NET开发科研成果管理系统

采用基于Microsoft.NET平台、用通用语言编译运行的程序-ASP.NET,设计开发了科研成果管理系统软件.该系统包括用户登录注册、文档管理、项目管理、用户管理、文档分类管理及附件管理6个模块.     

面向服务的旅游资源管理系统实现

研究旅游资源管理系统的实现方法和关键技术,介绍了天地图公共服务平台,设计了旅游资源专题数据库,实现了数据存储管理机制和调用流程,基于天地图地理信息公共服务平台实现了旅游景区一体化查询、精品路线推荐和公交换乘等功能。面向服务的旅游资源管理系统的应用结果表明,该系统能够为社会公众提供可视化、网络化的出行旅游地理信息服务,并且为城市旅游的科学管理和决策提供有力的技术支持。     

基于复杂性理论的城市经济网络研究进展与展望

城市经济网络的研究借鉴了复杂性理论的分析方法,能更细致地刻画城市网络的空间格局。现有的大量研究仍沿袭城市体系空间结构的思路,注重城市的竞争和位序关系以及城市网络的中心性,未能充分体现城市经济网络和城市体系空间格局的差异。本文通过对基本文献的梳理,从复杂性理论的视角将城市经济网络研究的发展历程分为3个阶段:20世纪40年代前的基础理论构建阶段;50-90年代的发展创新突破阶段以及21世纪以来的多元繁荣发展阶段。目前,城市经济网络研究的热点领域包括城市经济的拓扑结构和空间拟合、全球城市联系的范围测算和质量评价;城市经济网络结构的动力学影响以及城市经济网络的安全管控和功能优化。未来要关注大数据时代的数据整合和挖掘,构建城市经济网络的整体研究框架。     

我国劳动力市场动态均衡分析与实证研究

运用蛛网模型对劳动力市场进行动态均衡分析，给出劳动力市场均衡的条件及影响因素，利用中国劳动力市场的有关数据对其进行实证，采用时间序列分析方法对中国未来几年的劳动力市场均衡状态进行预测，并提出改善我国劳动力市场均衡状态的思路。     

BOOK REVIEWS

Books reviewed in this article: Aerial Photography and Remote Sensing Aerial photography and image interpretation for Resource Management . DAVID P. PAINE . Analytical Models and Techniques Spatial Processes Models and Applications A. D. CLIFF AND J. K. ORD Quantitative and Statistical Approaches to Geography: A Practical Manual JOHN A. MATTHEWS . Cartography and Maps Map Data Processing . HERBERT FREEMAN AND GOFFREDO G. PIERONI , eds. Computer-assisted Cartography: Principles and Prospects, 1982 . MARK S. MONMONIER . Cultural Navajo Architecture: Forms, History, Distributions . STEPHEN C. JETT AND VIRGINIA E . SPENCER . Rational Landscapes and Humanistic Geography . EDWARD RELPH . Economic The Structure and Control of a State Economy . W. L. L'ESPERANCE . Economic Geography . JAMES O. WHEELER AND PETER O. MULLER . The Myth of the Family Farm: Agribusiness Dominance of U.S. Agriculture . INGOLF VOCELER . Libya: The Experience of Oil . J. A. ALLEN . Geography of Public Finance, Welfare Under Fiscal Federalism and local Government Finance . ROBERT BENNETT . Environmental Management, Resources, and Systems Mountains and Man . LARRY W. PRICE . Environmental Geology . DONALD R. COATES . An Introduction to Environmental Systems . G. H. DURY . The Environment: Chinese and American Views . Edited by LAURENCE J. C. MA AND ALLEN G. NOBLE . Land Use in America . RICHARD H. JACKSON . Medical Conceptual and Methodological Issues in Medical Geography . MELINDA S. MEADE (ed.). Philosophy and Geographic Thought Birds in Egg/Eggs in Bird . GUNNAR OLSSON . PhysicaI Climatology: Selected Applications . J. E. OLIVER . Geomorphological Techniques . ANDREW GOUDIE (ed.). Political Politics, Geography and Behaviour . RICHARD MUIR AND RONAN PADDISON . The State of the World Atlas . MICHAEL KIDRON AND RONALD SECAL . Population The Population of the South . DUDLEY L. POSTON , JR . AND ROBERT H. WELLER , eds. Regional Latin America: Economic Development and Regional Differentiation . ARTHUR MORRIS . Developing the Amazon . EMILIO F. MORAN . Western Europe: A Systematic Human Geography . BRIAN W. ILBERY . Settlement Systems in Sparsely Settled Regions: The United States and Australia . RICHARD E. LONSDALEAND JOHN H. HOLMES , eds. African Perspectives: The Economic Geography of Nine African States . HARM DE BUJ AND ESMOND MARTIN , eds. Rural Nonmetropolitan America in Transition . AMOS H. HAWLEY AND SARA MILLS MAZIE , eds. Social Crime and Environment . R. NORMAN DAVIDSON . The Ghetto: Readings with Interpretations . JOE T. DARDEN , ed. Urban Urban Problems and Planning in the Developed World . MICHAEL PACIONE (ed.) Problems and Planning in Third World Cities . Edited by MICHAEL PACIONE . The City in West Europe . D. BURTENSHAW , M. BATEMAN , AND C. J. ASHWORTH .     

SOFTWARE REVIEWS

software reviews are in this article BMDP/PC CONCEPTS COMPUTERIZED ATLAS EVALUATION OF ALTERNATE PROPOSALS (EAP) EXTRA: EXPRESS TRANSIT ANALYSIS MATC CAD MOTORS TRANSPORTATION PACKAGE PCMAP: Thematic Mapping Software for the IBM Personal Computer, Version 2.3 PLACE TRANPLAN . US-ATLAS     

Energy distributions of the large-scale horizontal currents caused by wind in the baroclinic ocean

Wind is the main energy source for the generation of the internal waves and the ocean mixing. Wunsch[1] estimated that about 1 TW (1 TW = 1012 W) energy was transported into the ocean from the winds by us-ing the altimeter data. Watanabe et al.[2] numerically calculated that the mixing processes obtained 0.7 TW energy from the global wind, which afforded most of the energy needed by the maintenance of the Merid-ional Overturning Circulation (MOC). During the past 50 years, in the Norther…     

Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems

Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.