Water–rock interaction during the process of steam stimulation exploitation of viscous crude oil in Liaohe Shuguang Oil Field, Liaoning, China

In the process of steam stimulation exploitation of viscous crude oil, the injected water, at high temperature and under high pressure, reacts intensively with the host rock. This kind of water–rock interaction in Liaohe Shuguang Oil Field was studied on the basis of analysis of water composition changes, laboratory experiments, mineral saturation indices analysis, and mass balance calculation. Compared with the injected water, the changes of the composition of discharged water are mainly the distinct decrease of pH, Na⁺, SiO₂ and Cl⁻, as well as the increase of K⁺, Ca²⁺, Mg²⁺, SO ₄ ²⁻ and HCO ₃ ⁻ . Laboratory experiments under field conditions showed: the dissolution sequence of minerals quantitatively is quartz>potassium feldspar>albite, and the main change of clay minerals is the conversion of kaolinite to analcime. Mass balance calculation indicated during the process of steam stimulation, large quantities of analcime are precipitated with the dissolution of large amounts of quartz, kaolinite, potassium feldspar, and CO₂. These results correlated very well with the experimental results. The calculated results of Liaohe Shuguang Oil Field showed that during the steam stimulation for viscous crude oil, the amounts of minerals dissolved (precipitated) are huge. To control the clogging of pore spaces of oil reservoirs, increased study of water–rock interaction is needed.     

Mongolian gerbils and Daurian pikas responded differently to changes in precipitation in the Inner Mongolian grasslands

Mongolian gerbils (Meriones unguiculatus) and Daurian pikas (Ochotona dauurica) are two key small mammal species in the Inner Mongolian grasslands, China. Mongolian gerbils displayed density-dependent population growth, but the time lag of density dependence was short and within season. The spring–autumn population growth rate was inversely related to population density in Mongolian gerbils of the Erdos desert grasslands. The autumn–spring population growth rate of Mongolian gerbils was inversely related to winter precipitation. Precipitation had stronger effects on the population growth of gerbils during the non-breeding season. The monthly population growth rate of Daurian pikas was positively related to the monthly precipitation and was inversely related to population density in central Inner Mongolia. Daurian pikas select habitats with tall plants. Increased precipitation enhances plant production and increases the height of plants in arid and semi-arid regions. This enhancement of plant height might increase the population growth of Daurian pikas. Mongolian gerbils live in short grasslands. Increased winter precipitation might result in higher winter mortality of Mongolia gerbils, or taller plants might supress gerbil population growth in wet years. Therefore, responses of small mammal species to changes in precipitation depend on the life history of small mammals and changes in vegetation induced by climatic changes.     

Hydrogeochemical evolution of groundwater in a Mediterranean coastal aquifer, Mersin-Erdemli basin (Turkey)

In this study, hydrogeologic and hydrochemical information from the Mersin-Erdemli groundwater system were integrated and used to determine the main factors and mechanisms controlling the chemistry of groundwaters in the area and anthropogenic factors presently affecting them. The PHREEQC geochemical modeling demonstrated that relatively few phases are required to derive water chemistry in the area. In a broad sense, the reactions responsible for the hydrochemical evolution in the area fall into four categories: (1) silicate weathering reactions; (2) dissolution of salts; (3) precipitation of calcite, amorphous silica and kaolinite; (4) ion exchange. As determined by multivariate statistical analysis, anthropogenic factors show seasonality in the area where most contaminated waters related to fertilizer and fungicide applications that occur during early summer season.     

基于LBS的嵌入式GIS研究--以北京市综合交通信息平台设计为例

GIS是LBS的位置定位、导航及地图表达的基础技术支撑。针对LBS的固定服务端与移动终端的信息交互需求，提出了平台GIS与移动GIS的概念；针对移动GIS，提出了嵌入式、软件插件组合技术，确定了无线下载的事件表结构；将此用于北京市交通综合信息平台设计，实现了LBS的数据与业务分离、实时信息的自动交互、移动终端的位置确定与表达。     

Soluble organic compounds in fog and cloud droplets: what have we learned over the past few years?

We have recently set up a new procedure for characterising the water soluble organic compounds (WSOC) in fog water, for which information is still rather limited. Fog samples collected during the 1998–1999 fall–winter season in the Po Valley (Italy) were analysed following this procedure, which allows a quantitative determination of three main classes of organic compounds (neutral species, mono- and di-carboxylic acids, polycarboxylic acids), together accounting for ca. 85% of the total WSOC. This procedure also provides information on the main chemical characteristics of these three classes of compounds (functional groups, aliphatic vs. aromatic character, etc.). The enhanced chemical knowledge on fog/cloud chemical composition opens new scenarios as far as chemical and microphysical processes in clouds and fogs are concerned.     

均匀土-箱基-结构相互作用体系的计算分析

采用通用有限元程序ANSYS，针对捱动台试验中的均匀土-箱基-结构试验进行了三维有限元分析，计算中土体的本构模型采用等效线性模型，利用面-面接触单元考虑土体与基础交界面的状态非线性。计算表明，基础底面和土体发生滑移，基础侧面和土体之间发生了滑移和脱离，上部结构柱顶加速度反应主要由基础转动引起的摆动分量组成，通过与试验结果的对照研究，二者得出的规律基本一致，验证了采用的计算模型与分析方法的合理性，为进一步计算研究和实际工程应用奠定了基础。     

Seismic analysis of base-isolated liquid storage tanks using the BE–FE–BE coupling technique

A three-dimensional soil–structure–liquid interaction problem is numerically simulated in order to analyze the dynamic behavior of a base-isolated liquid storage tank subjected to seismic ground motion. A dynamic analysis of a liquid storage tank is carried out using a hybrid formulation, which combines the finite shell elements for structures and the boundary elements for liquid and soil. The system is composed of three parts: the liquid–structure interaction part, the soil–foundation interaction part, and the base-isolation part. In the liquid–structure interaction part, the tank structure is modeled using the finite elements and the liquid is modeled using the internal boundary elements, which satisfy the free surface boundary condition. In the soil–foundation interaction part, the foundation is modeled using the finite elements and the half-space soil media are modeled using the external boundary elements, which satisfy the radiation condition in the infinite domain. Finally, above two parts are connected with the base-isolation system to solve the system's behavior. Numerical examples are presented to demonstrate the accuracy of the developed method, and an earthquake response analysis is carried out to demonstrate the applicability of the developed technique. The properties of a real LNG tank located in the west coast of Korea are used. The effects of the ground and the base-isolation system on the behavior of the tank are analyzed.     

液化场地桩-土-桥梁结构动力相互作用振动台试验研究进展

本文在全面归纳与总结液化场地桩－土－桥梁结构动力相互作用振动台试验及与之相关领域的国内外研究进展基础上，直接针对我国桥梁工程中的主要震害问题，提出在我国开展液化场地桩－土－桥梁结构动力相互作用振动台试验研究的必要性，并阐述作者对液化场地桩－土－张桥梁结构动力相互作用振动台试验中若干问题的认识。