地下水及溶质运移数值模拟系统

介绍了地下水及溶质运移数值模拟的研究进展、数值模型的分类和数值模拟的步骤。根据数值模拟中涉及到的地质信息资源的特点，提出了基于地理信息系统(GIS)技术的地下水及溶质运移数值模拟系统的设计思路。该系统能够对模拟区域的基础地质资料、水文地质勘探资料以及数值模型的输入、输出资料进行动态管理，而且随着勘探、科研和生产的不断进行，通过对数据库的及时更新以及对数值模型的不断校正，可为不同的科研和生产方案的预测与评价提供信息资源。     

The design of post‐mining landscapes using geomorphic principles

Nature can provide analogues for post‐mining landscapes in terms of landscape stability and also in terms of the rehabilitated structure ‘blending in’ with the surrounding undisturbed landscape. In soil‐mantled landscapes, hillslopes typically have a characteristic pro?le that has a convex upper hillslope pro?le with a concave pro?le lower down the slope. In this paper hillslope characteristic form is derived using the area–slope relationship from pre‐mining topography at two sites in Western Australia. Using this relationship, concave hillslope pro?les are constructed and compared to linear hillslopes in terms of sediment loss using the SIBERIA erosion model. It is found that concave hillslopes can reduce sediment loss by up to ?ve times that of linear slopes. Concave slopes can therefore provide an alternative method for the construction of post‐mining landscapes. An understanding of landscape geomorphological properties and the use of erosion models can greatly assist in the design of post‐mining landscapes. Copyright © 2003 John Wiley & Sons, Ltd.     

基于GIS和SD方法的社会经济发展与生态环境响应动态模拟预测研究

在着重于空间现象分析处理的GIS与动态模拟的SD方法结合的模式下，动态模拟预测了不同社会经济发展策略对生态环境的影响，揭示了生态经济系统社会经济发展与生态环境相互影响关系，为区域可持续发展提供决策支持服务。     

水下无源导航系统仿真匹配算法研究

针对水下无源导航(地形辅助导航)系统的特点，充分利用各种海洋地理特征传感器获取信息，进行数据预处理、算法分析、性能评估，然后进行智能数据融合，进而完成水下无源导航系统模块化的仿真设计，为水下无源导航系统的进一步研究提供可行的方法和技术。仿真结果表明，采用水下地形匹配辅助导航，能够有效地修正惯导误差达到设计要求，为真实海洋环境下的精确导航提供可靠的技术依据。     

虚拟加工环境中的工件动态建模方法研究

提出并实现了基于平面纹理映射的基元立方体构造方法，以之为动态结点建立了动态八叉树结构，实现了支持变精度动态建模的自相似递归算法。该算法确保离正在加工的部位更近的区域有更高的精度，并采用C^ Builder和OpenGL构造了一个集成于虚拟加工环境的可加工工件模型。     

基于GPS基准站网的GPS测量

采用基于GPS基准网的GPS测量可以提高GPS测量的可靠性和准确性 ,可以消除和减小GPS测量观测值中与时间和空间相关的大气误差和轨道误差的影响 ,使中、长距离快速静态定位和RTK动态定位成为现实 ,还具有可直接得到WGS84Z坐标等优点。本文介绍基于GPS基准站网的GPS测量 ,简要地论述GPS虚拟参考站法VRS和区域改正数法FKP的原理、方法和特点 ,以及目前实施中存在的一些问题     

Atomistic simulation of the structure and elastic properties of pyrite (FeS2) as a function of pressure

Interatomic potential parameters have been derived at simulated temperatures of 0 K and 300 K to model pyrite FeS₂. The predicted pyrite structures are within 1% of those determined experimentally, while the calculated bulk modulus is within 7%. The model is also able to simulate the properties of marcasite, even though no data for this phase were included in the fitting procedure. There is almost no difference in results obtained for pyrite using the two potential sets; however, when used to model FeS₂ marcasite, the potential fitted at 0 K performs better. The potentials have also been used to study the high-pressure behaviour of pyrite up to 44 GPa. The calculated equation of state gives good agreement with experiment and shows that the Fe–S bonds shorten more rapidly that the S–S dimer bonds. The behaviour of marcasite at high pressure is found to be similar to that of pyrite.     

Are catch-up reefs an artefact of coring?

Drill cores through modern coral reefs commonly show a time lag in reef initiation followed by a phase of rapid accretion to sea level from submerged foundations – the so-called ‘catch-up response’. But because of the difficulty of drilling in these environments, core distribution is usually restricted to accessible areas that may not fully represent reef history, especially if the reef initiated in patches or developed with a prograde or retrograde geometry. As a consequence, core data have the potential to give a misleading impression of reef development, particularly with respect to the timing of initiation and response to sea-level rise. Here, we use computer models to simulate keep-up reef development and, from them, quantify variations in the timing of reef initiation and accretion rate using mock cores taken through the completed simulations. The results demonstrate that cores consistently underestimate the timing of reef initiation and overestimate the reef accretion rate so that, statistically, a core through a keep-up reef will most likely produce a catch-up pattern – an initiation lag followed by a phase of rapid accretion to sea level. This implies that catch-up signatures may be an artefact of coring and that keep-up reefs are significantly more common than previous core studies claim.     

Pull-down basin in the central part of Japan due to subduction-induced mantle flow

The driving force for the basin subsiding against isostatic balance in and around Lake Biwa in the Kinki district, Japan is discussed. The lake region is characterized by strong negative Bouguer anomalies, especially by a steep horizontal gradient zone of gravity anomaly running along the western margin of the lake. The large negative anomaly (>50 mgal) cannot be explained by low-density sediments beneath it. A down-warping structure extending to the Moho depth should be taken into account. This conjecture has been strongly supported by a short-period receiver function imaging, which shows a clear offset of about 8 km for the Moho discontinuity under the steep gravity gradient zone.A question arises as to what is the driving force to create such a large down-warping structure. We consider that the subduction of the shallow-dipping slab under the region (Philippine Sea Slab) may cause crustal deformation by dragging the viscous mantle downward. In order to verify this model, we simulated the induced mantle flow due to the subduction of the Philippine Sea Slab and the pressure distribution on the crust–mantle boundary. This numerical experiment showed that the induced flow makes a strong negative pressure zone under the lake region if the slab has a vertical offset along the direction of subduction. This offset of the slab is consistent with plate models deduced from hypocentral distributions and Sp phases of the deep-focus earthquakes.     

新疆某水利枢纽工程软弱结构面抗剪强度参数的试验研究

某水利枢纽工程位于伊犁地区,影响工程的主要问题为坝基岩体软弱结构面和断层的抗滑稳定问题。根据工程实际条件和软弱夹层特性,采取现场断层软弱结构面试验和室内模拟试验相结合,获得软弱夹层的抗剪参数。实践证明,把两种方法结合起来的试验成果可靠,尤其对一些不具备进行现场大型岩体软弱夹层抗剪试验的工程,采用室内中型直剪仪进 行剪切试验具有实用意义。