Global force balance of region 1 current system

At times of strong solar wind forcing such as those that produce major magnetic storms, the region 1 current system dominates over the Chapman–Ferraro current system in mediating the transfer of force between the solar wind and the terrestrial system. The global force balance can be broken into two components, one involving the high-altitude part of the region 1 current system that is in contact with the solar wind (labeled here the HRS) and the other involving the low-altitude part of the region 1 current system that lies in the ionosphere (the LRS). Both communicate their J×B force to the geomagnetic dipole via a gradient in the magnetic field that they generate. In the HRS case the force acts to push the dipole away from the sun. This is the region 1 analog of the Chapman–Ferraro mechanism for transmitting the solar wind's force to the Earth. However, in the LRS case, the force (which is much stronger than in the HRS case) acts to push the dipole toward the sun, seemingly paradoxically. The LRS balances the ‘paradoxical’ sunward force on the dipole with an opposite force on the atmosphere. This paper uses MHD simulations to demonstrate the presence of both the normal force-transmitting gradient generated by the Chapman–Ferraro and the counter-Chapman–Ferraro gradient in the magnetic field generated by the region 1 current system.     

Static and dynamic response of massive caisson foundations with soil and interface nonlinearities—validation and results

The static, cyclic, and dynamic response of a massive caisson foundation embedded in nonlinear layered or inhomogeneous soil and loaded at its top is investigated. The caisson is supported against horizontal displacement and rotation by four types of inelastic springs and dashpots, described with the BWGG model that was developed in the preceding companion paper [Gerolymos N, Gazetas G. Development of winkler model for static and dynamic response of caisson foundations with soil and interface nonlinearities. Soil Dyn Earthq Eng, submitted companion paper]. The prediction of the model is satisfactorily compared with results from 3D-finite element analysis. Some experimental corroboration of the method is provided with the help of a 1/3-scale lateral load test that had been conducted in the field by EPRI. An illustrative example of a caisson embedded in linearly-inhomogeneous clay and subjected to static and dynamic loading is analysed. Characteristic results are presented highlighting the role of soil inelasticity and its interplay with the two dominant interface nonlinearities: separation (gapping) of the caisson shaft from the surrounding soil, and uplifting of the base from the underlying soil.     

1-（4-硝基苯基）-3-（3，5-二溴吡啶）三氮烯的合成及其与镍的显色反应

合成了1-(4-硝基苯基)-3-(3,5-二溴吡啶)三氮烯(NPDBPDT),并研究了NPD-BPDT与镍的显色反应。在pH 10.0的Na2B4O7-NaOH缓冲溶液介质中,表面活性剂Triton X-100存在下,镍与试剂生成摩尔比为1∶4的络合物在470 nm处有最大正吸收峰,表观摩尔吸光系数为1.02×105L.mol-1.cm-1;在540 nm处有最大负吸收峰,表观摩尔吸光系数为1.15×105L.mol-1.cm-1;以540 nm为参比波长、470 nm为测量波长进行双波长测定,表观摩尔吸光系数为2.17×105L.mol-1.cm-1。镍含量在0~480μg/L内符合比尔定律。方法用于合金样品中镍的测定,结果与原子吸收法相符,加标回收率为98.0%~102.0%;精密度小于5%(RSD,n=6)。     

地质公园三维电子地图的设计与实现

结合三维建模和电子地图的基本理论,根据地质公园的特点,利用ERDAS实现大面积区域三维可视化,并结合3DS MAX丰富的建模技术及强大的动画制作功能,在地质景观演化方面做了初步探讨。采用“超地图”的形式来组织各种地图数据以及超媒体相关信息,从内容结构设计及特点进行论述,实现了伊通火山群的三维电子地图,展示出“伊通型火山”的特点。为科研、科普和旅游提供了方便、直观的信息表现形式,拓宽了电子地图的应用领域,同时也丰富了电子地图的研究内容。     

利用高分辨率影像建立三维虚拟校园——以"数字成都理工大学"为例

以数字化校园工程———“数字成都理工大学”为例,探讨利用航空影像和数字摄影测量技术,获取基础空间地理信息的方法及途径。并采用三维建模软件Cyber C ity对建筑物进行三维建模。而对于复杂地物,采用三维地理信息系统IMAGIS软件建立单个模型,从而实现了成都理工大学校区的三维可视化虚拟重建和漫游。实践证明,利用数字摄影测量技术和遥感影像,能够有效地获取大范围区域地表地物的三维信息,并快速地建立地面模型和三维景观。     

非均匀介质中交错网格高阶有限差分数值模拟

地震波场的数值模拟一直是地球物理学的一个重要的研究领域,而在数值正演模拟方法的研究中,计算精度和计算效率是评价该方法有效性及优越性的二个关键问题。这里从一阶速度—应力弹性波动方程出发,着重介绍如何构造离散化模型的网格,如何求解空间导数,如何选取边界条件等内容,从而更有效地提高数值计算的精度与计算效率。文中构造了不同类型的介质模型,并在交错网格中,利用高阶有限差分模拟非均匀介质的波场传播。模拟结果表明,该方法实现简单,具有很好地稳定性和较高的精度,能够直观、高效地反映出介质中波场的传播规律。     

井地直流电法三维数值模拟中若干问题研究

讨论了地下垂直线源分段计算和场叠加的方法,并实现了在套管上供直流电的三维数值模拟。讨论了大型容量矩阵的压缩存储方式,采用数组和结构体相结合的方法实现容量矩阵的一维链表式压缩存储。在求解超大型稀疏线形方程组时引入不完全Cholesky分解稳定化的双共轭梯度算法(ICBG),通过与均匀半空间垂直线源解析解的对比,证明了该算法是准确可靠的。     

库车坳陷西段出露盐体的溶解物理模拟

库车坳陷西段古近系库姆格列木群中分布着巨厚的盐岩层,喜山末期构造运动使得大量的盐体在库车前陆褶皱冲断带前缘被逆冲推覆至地表,遭受大气降水的溶解.除了平衡剖面恢复所得出的缩短量之外,盐推覆构造的逆冲推覆距离还应包括溶解盐体的厚度.通过采集研究区出露地表的盐岩样品,进行溶解物理模拟实验,估算自1.64Ma以来,研究区出露盐体的溶解厚度为3.969~14.727km.根据前人利用平衡剖面恢复所计算出该区的盐推覆构造的最大推覆距离为30km以上,从而得出该区的盐推覆构造的最大推覆距离为44.727km以上.     

三维质点追踪模型及其在胶南海域的应用

在已建立的变边界河口、陆架、海洋模型(ECOM)的基础上添加一个变边界质点追踪模块,研究胶东半岛南海域的物质输运特征,讨论了三维空间中,水质点在潮流作用下的迁移特点.该模型在近海海洋环境管理上具有实用价值.     

斜坡上异重流的三维数值模拟

针对异重流的流动特征,建立了适用于具有各向异性浮力紊动特征的三维异重流运动的数学模型,并模拟了异重流在15°斜坡底面上的潜行过程。计算结果准确地模拟了异重流的运动特征和形态,其前锋的潜行速度与实验结果相当吻合。该模型采用非结构同位网格上的SIMPLEC算法能适应复杂边界和地形,可应用于自然界实际环境中异重流的演进计算。