驱动重联过程中等离子体团的聚合

本文对驱动重联过程作了二维可压缩磁流体动力学模拟．对于长的计算域（１：４），在持续入流的作用下形成了双重磁岛结构，这些磁岛在向外运动的过程中不断靠近，逐渐聚合成为一个大的等离子体团，并继续向外运动．这说明在地球磁层顶和磁尾所观测到的大尺度磁结构，很可能是在驱动重联过程中，由较小的等离子体团聚合后形成的．并初步揭示了在空间等离子体中，磁岛的聚合过程难以直接观测的动力学原因．     

安徽绩溪伏岭岩体隆升时代的磷灰石裂变径迹证据

安徽绩溪伏岭岩体位于安徽省南部、黄山花岗岩体的东部。伏岭岩体裂变径迹（AFT）热年代分布于51±5～68±7 Ma之间,围限径迹长度为11.9～12.9μm。岩体形成之后,所在山系经历了速率波动较大的隆升过程,至55 Ma期间为一加速隆升过程,到55 Ma时速度达到最大的73 mm/ka;随后速度减缓,54 Ma左右时的平均抬升速率为60 mm/ka;54～51 Ma间又是一个快速加速隆升时期,到51 Ma时,速度达到70 mm/ka。研究区具有三个主要的冷却剥露阶段：130～116 Ma左右,冷却速率约为1.34℃/Ma;70～60 Ma左右,进入第二个较为快速冷却阶段,冷却速率约为25℃/Ma;在7～8 Ma左右发生突然加剧冷却事件,持续至今,速率达到8℃/km。总体来说,伏岭岩体经历了速率逐渐增加的冷却过程。由于黄山山体与伏岭岩体在大地构造位置、岩性特征及侵入时间上具有很大的相似性,二者的隆升时代、速率以及抬升剥蚀量是大致相当的。     

碳酸盐型盐湖卤水的模拟太阳池结晶试验

在碳酸盐型盐湖提锂工艺中, 太阳池是一个重要组成部分, 目的是储存太阳能能量以结晶析出碳酸锂。文章利用加热方法首次在实验室条件下进行模拟太阳池结晶试验, 试验的蒸发量随着温度的升高而加大, 但蒸发量的不同对析盐结晶影响不大。在不同时间段模拟试验中, 24 h时间段的Mg2+析盐浓度较Li+大, 且随着时间的延长逐渐降低, 而Li+则相反;Mg2+析出速率随着时间的增加而逐渐降低, 而Li+析出速率基 本保持一致。在不同温度模拟试验中, 卤水主要组分总析出率与温度的升高呈正相关, 卤水中CO32?和Li+的浓度降低速度大于其他组分, CO32?和Li+的析出率远大于其他组分, 析出主要矿物鉴定结果均为扎布耶石     

GALILEO系统仿真与分析

本文着重阐述了GALILEO仿真系统星座和误差模型的构建过程,利用该系统进行DOP值分析并通过定位解算验证了GALILEO系统的性能指标。通过与GPS系统性能指标进行比较,得出GALILEO系统的星座设计具有较好的DOP值分布特性,定位精度优于GPS定位精度。在进行差分定位时,其误差贡献比较大的是接收机噪声和卫星钟差,因此提高差分定位的关键是降低接收机的噪声水平和提高卫星钟差预报精度。     

地下水数值计算中断层处理的"切割-导通法"

从对断层导水性能的分析出发 ,提出了地下水数值计算中断层处理的“切割—导通法” ,既考虑断层侧向导水性 ,又考虑了其垂向导水性 ,更符合断层导水的实际情况 ,也易于描述较大断裂在走向上的导水性差异。     

Numerical Calculation of Equivalent Cell Permeability Tensors for General Quadrilateral Control Volumes

A new method for upscaling fine scale permeability fields to general quadrilateral-shaped coarse cells is presented. The procedure, referred to as the conforming scale up method, applies a triangle-based finite element technique, capable of accurately resolving both the coarse cell geometry and the subgrid heterogeneity, to the solution of the local fine scale problem. An appropriate averaging of this solution provides the equivalent permeability tensor for the coarse scale quadrilateral cell. The general level of accuracy of the technique is demonstrated through application to a number of flow problems. The real strength of the conforming scale up method is demonstrated when the method is applied in conjunction with a flow-based gridding technique. In this case, the approach is shown to provide results that are significantly more accurate than those obtained using standard techniques.     

Study on rain-runoff process in the peripheral mountainous area of the Sichuan Basin

Studies on rain-runoff process in the peripheral mountainous area of the Sichuan Basin, which is regarded as a key ecological shelter, will contribute to flood control and environmental protection for the Upper Yangtze River Basin. In two typical catchments--the Fujiang River Catchment and the Wujiang River Catchment, rainfall simulations have been conducted to study the rain-runoff processes of yellow soil and limestone soil in three types of land use--forestland, farmland and grassland. Results showed that （1） within the same rainfall process, overland flow occurs first on farmland, then on grassland, and finally on forestland; （2） soil surface coverage has a great impact on the occurrence and amount of overland flow. The runoff amount can increase 2-4 times after the coverage is removed; （3） the infiltration before the occurrence of overland flow will decrease because of higher gravel contents of soil, but it takes no effect on infiltration once overland flow becomes stable; （4） the runoff coefficient of the limestone soil forestland is greater than that of the yellow soil forest land, but less than that of the farmland; （5） three empirical infiltration models, including Horton＇ model, Kostiakov＇ model, and modified Kostiakov＇ model, were compared by using the observed results under rainfall simulation. The results showed that the Kostiakov＇ model performed better than both the Horton＇ model and modified Kostiakov model. According to the results of this research, the Kostiakov＇s model can be used to simulate rainfall infiltration when water erosion is modeled in the peripheral mountainous area of the Sichuan Basin.     

Spectral Simulation and Conditioning to Local Continuity Trends in Geologic Modeling

Spectral simulation has gained application in building geologic models due to the advantage of better honoring the spatial continuity of petrophysical properties, such as reservoir porosity and shale volume. Distinct from sequential simulation methods, spectral simulation is a global algorithm in the sense that a global density spectrum is calculated once and the inverse Fourier transform is performed on the Fourier coefficient also only once to generate a simulation realization. The generated realizations honor the spatial continuity structure globally over the whole field instead of only within a search neighborhood, as with sequential simulation algorithms. However, the disadvantage of global spectral simulation is that it traditionally cannot account for the local information such as the local continuity trends, which are often observed in reservoirs and hence are important to be accounted for in geologic models. This disadvantage has limited wider application of spectral simulation in building geologic models. In this paper, we present ways of conditioning geologic models to the relevant local information. To account for the local continuity trends, we first scale different frequency components of the original model with local-amplitude spectrum ratios that are specific to the local trend. The sum of these scaled frequency components renders a new model that displays the desired local continuity trend. The implementation details of this new method are discussed and examples are provided to illustrate the algorithm.     

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。     

太湖梅梁湾藻类生态模拟与蓝藻水华治理对策分析

根据目前对太湖梅梁湖生态环境的认知,建立该湖区藻类生态动力学模型进行生态模拟,基于模拟结果对太湖富营养化中最严重的蓝藻水华治理与污染物排放控制和清淤工程进行了分析。结果显示;太湖污染物排放达标将极大改善富营养水平;但应结合经济分析和效益分析,通过组合各类污染物控制总量来达到最优治理效果,模拟分析表明,单一清淤工程对于富营养化中蓝藻水华治理意义有限。