地理信息系统的数据模型与系统结构

数据模型是描述数据内容及其相互关系的工具，它是数据库设计的核心问题之一。空间数据相对于一般事务性数据具有数据量大和更加复杂的特点，因此，地理信息系统（ＧＩＳ）中空间数据模型的研究显得尤为重要。商业化的ＧＩＳ一般采用关系数据模型，而关系数据模型缺乏表达空间实体及其相互关系的能力，因此形成了图形库与属性库相分离的ＧＩＳ系统结构。这种结构不便于空间实体的整体管理。为解决这一问题，人们探索了扩展的关系模型和面向对象的数据模型。本文介绍了这三种ＧＩＳ数据模型及其与之对应的三种系统结构，分析了这些模型与系统结构的优越性和不足之处，并揭示了数据模型与系统结构之间的内在关系。     

皖南地区大隆组页岩生物标志化合物特征及其地质意义

为阐明下扬子皖南地区上二叠统大隆组页岩特征,通过对港地1井岩心进行取样,开展了大隆组页岩样品的有机地球化学测试、氩离子抛光-扫面电镜观察、矿物组成分析等工作.结果表明皖南地区大隆组页岩TOC含量为1.18%～4.35%,干酪根以Ⅰ型为主,少数为Ⅱ₁型,Ro介于1.15%～1.29%,反映大隆组页岩整体处于成熟的生油气阶段.饱和烃气相色谱图呈典型的单峰型分布,正构烷烃主峰碳数分布在nC₁₈～nC₂₂之间,nC₂₅₊高碳数正构烷烃含量较低.规则甾烷的丰度整体上表现为C₂₇≈C₂₉>C₂₈,属于V型分布,且高、低碳数的正构烷烃单体碳同位素δ¹³C相差较大(3.0‰～5.6‰),略高于单一来源的不同碳数正构烷烃的δ13C变化(一般小于1.6‰),反映大隆组页岩有机质主体来源于菌藻类等低等水生生物,局部存在陆源高等植物.TOC与TS的相关性、Pr/Ph比值、Pr/nC₁₇-Ph/nC_1...     

青藏高原南部邛多江盆地新建更新统洛村组地层特征及意义

错那-沃卡裂谷是青藏高原南部的众多新生代南北向裂谷之一,该裂谷中段的邱多江盆地沉积了大面积的第四纪湖相沉积物。此前由于地质调查程度较低,古湖积物的地表调查工作基本属于空白。本次调查对洛村-邛多江盆地古湖积物进行了详细研究,在洛村地区发现了完整的古湖积物的连续沉积,测制了地层剖面,开展了精确的光释光定年分析,结果显示其沉积时代为上更新世。鉴于区域上该套更新世地层出露面积广、厚度大,故新建地层单元,定名为洛村组(Qp 3 lc);并推测邱多江-洛村古湖可能是雅鲁藏布江中部超大古堰塞湖的一部分,洛村组是由藏南地区错那-沃卡裂谷和古大湖共同作用形成,初步计算了古湖出水口、湖面高度、湖水面积等参数。     

关中—天水经济区城市群人口经济与资源环境发展耦合协调性分析

以关中-天水经济区城市群为研究对象,分别构建资源环境和人口经济系统的综合评价指标体系,采用主成分分析法,对该经济区主要城市2002年和2011年资源环境和人口经济的发展指数及其耦合协调度进行测评,并探究其时空差异性。结果表明:2002-2011年其城市资源环境发展水平上升的有渭南、商洛和天水,下降的有西安、铜川、宝鸡、咸阳和杨凌;人口经济发展上升的有西安、铜川、宝鸡、咸阳、渭南和商洛,下降的有天水和杨凌;各主要城市的资源环境与人口经济发展水平及其耦合协调性的空间差异明显,多数城市资源环境与人口经济的耦合协调性不尽合理,且出现衰退趋势。最后就该城市群实现资源环境与人口经济协调发展提出建议和对策。     

Transient analysis of the source of water to wells: Cape Cod, Massachusetts

A transient flow modeling analysis for potential public-supply wells on western Cape Cod, Massachusetts, demonstrates the difference between transient and steady-state recharge areas can have important implications for wellhead protection. An example of a single pumping well illustrates that commonly used steady-state time-related capture areas do not represent the recharge area and travel times of water being pumped from the well until sufficient time has elapsed for steady-state flow conditions to be established. Until that time, transient recharge areas are needed to account for the portion of water discharging from the well that entered the aquifer before pumping started. An example of two pumping wells demonstrates the same area at the water table cannot supply water to more than one well under steady-state flow conditions. Transient recharge areas to multiple wells can overlap, however, until steady-state flow conditions are established. The same area can, therefore, be a source of water to more than one well during early pumping times, and the water pumped from a given well may derive from source areas, including contaminated areas, that do not lie within the well's steady-state recharge area.     

Inorganic species in geologic fluids: correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes

Correlations among experimentally determined standard partial molal thermodynamic properties of inorganic aqueous species at 25 degrees C and 1 bar allow estimates of these properties for numerous monatomic cations and anions, polyatomic anions, oxyanions, acid oxyanions, neutral oxy-acid species, dissolved gases, and hydroxide complexes of metal cations. Combined with correlations among parameters in the revised Helgeson-Kirkham-Flowers (HKF) equation of state (Shock et al., 1992), these estimates permit predictions of standard partial molal volumes, heat capacities, and entropies, as well as apparent standard partial molal enthalpies and Gibbs free energies of formation to 1000 degrees C and 5 kb for hundreds of inorganic aqueous species of interest in geochemistry. Data and parameters for more than 300 inorganic aqueous species are presented. Close agreement between calculated and experimentally determined equilibrium constants for acid dissociation reactions and cation hydrolysis reactions supports the generality and validity of these predictive methods. These data facilitate the calculation of the speciation of major, minor, and trace elements in hydrothermal and metamorphic fluids throughout most of the crust of the Earth.     

前言——我们的共同记忆与理想

2007-08-28 是中国科学院暨香港中文大学地球信息科学联合实验室成立10周年的纪念日,曾经在实验室学习与工作过的学生与学者从国内外回到香港中文大学未圆湖畔,报告自己的研究进展,以学术研讨会的形式展现我们的共同记忆与理想.专栏收集的论文是研讨会中的部分报告,以此形成我们10周年纪念的成果之一.     

Electrokinetic migration of permanganate through low-permeability media

This research was conducted to evaluate the combination of electromigration and potassium permanganate as a potential remediation method for low-permeability media (e.g., soil and sediment) contaminated with dissolved and sorbed organic contaminants. The experimental procedure was composed of two stages: determination of migration rates of permanganate through homogeneous cores and a primarily qualitative analysis of migration in more heterogeneous, two-dimensional scenarios. Results indicated that transport of permanganate through fine-grained porous media and clays can be undertaken using electromigration, and electromigration rates were found to be at least 400% faster than diffusion alone. In addition, the use of an applied electric field in a flushing scenario was shown to result in almost 100% sweep efficiency of a domain consisting of clay blocks interspersed in a glass bead medium. The results of the study show that there is potential for this method to be able to deliver permanganate and other potential remedial agents to treat contaminated zones within heterogeneous and low-permeability porous media through in situ chemical oxidation or other processes.     

GeoSQL：一种可视化空间扩展SQL查询语言

根据结构化查询语言ＳＱＬ的基本原理,设计了空间查询语言ＧｅｏＳＱＬ及其表达形式、界面设计和实现方法。ＧｅｏＳＱＬ的特色为：（１）采用子查询重组ＦＲＯＭ语句,使其符合一般空间操作的程序（２）ＧｅｏＳＱＬ的界面设计融入Ｉｃｏｎ、Ｌｉｓｔｏｘ等可视化部件,易于查询本的形成,且减少了语法错误。