在有序表中搜索插值点

通过实验介绍了在插值算法中如何快速有效地搜索插值节点,以减少计算量和误差,使构造的函数逼近“真实”函数。     

三维径向点插值无网格法及其在流固耦合中的应用

径向基函数点插值无网格法(radial point interpolation method,RPIM)是一种新型的无网格法,其形函数具有插值特性,且形式简单,易于施加本质边界条件。文中介绍了径向基函数点插值无网格法的基本原理,推导了三维情况下点插值无网格法的基本公式。从变分原理出发,结合比奥固结理论,建立了流-固耦合的三维点插值无网格法基本方程和数值积分方法,并开发了相应计算程序。通过三维悬臂梁和单向固结问题的数值试验,验证了该方法对三维弹性问题和流-固耦合问题的适用性和有效性     

基于空间散乱点插值的曲面重构

采用最近邻点法、距离反比加权法和克里格法等空间插值方法,基于IDL语言实现插值算法,对我国西部某金属矿山坑道内,利用大功率充电法测得的163个电位数据进行曲面重构,结果表明,克里格插值方法更能够真实地反映空间数据变量(场)的分布特性,具有广泛的实用价值。     

自然邻点插值算法及其在二维不规则数据网格化中的应用

由于观测数据的不足,对不规则散点数据的二维插值在地球物理中应用非常广泛。这里研究并实现了自然邻点二维插值算法,并以一个大地电磁测深反演数据为例,验证了该方法的可行性与效果。实际资料试算与成图结果表明,该方法具有精度高、插值效果好、速度快以及便于模拟地形数据等优点。     

基于单位分解的扩展径向点插值无网格法

针对线弹性断裂力学问题,提出扩展径向点插值无网格法（X-RPIM）。该方法基于单位分解思想,在传统径向点插值无网格法的位移模式中加入扩展项来描述裂纹两侧的不连续位移场和裂尖奇异场。由于其形函数具有Kronecker ? 函数性质,易于施加本质边界条件。详细描述了X-RPIM不连续位移模式的建立,支配方程的离散形式以及J积分计算混合模式裂纹的应力强度因子的实现过程,讨论了不同积分区域对应力强度因子的影响。数值算例分析证明了该方法在求解断裂问题时的可行性和有效性,同时说明扩展径向点插值无网格法在模拟裂纹扩展问题时具有良好的前景。     

地层划分中有序地质量分割法

有序地质量最优分割法,目前国内应用较广,而一些简便分割法却不多见。本文欲对所知的几种方法予以比较,并提出增补意见。一最早由费歇(Fisher,1958)提出的有序样品聚类法(最优分割法),简称V型法,是目前地层划分中较普遍采用的数学方法。 V型法从有序样品分段的段内特征差异尽可能小,段间特征差异尽可能大的原则出发,寻求最优的分段结果。在数学上用方差(或离差平方和)来定义。     

有序聚类分析法的改进及其在水文序列突变点识别中的应用

有序聚类分析法是水文学中识别突变点的有效方法,但该法只考虑了同类之间的离差较小原则,忽略了类与类之间的离差较大原则。基于此,提出了改进的有序聚类分析法,改进法同时考虑了同类之间的离差较小和类类间的离差较大原则。将改进的有序聚类分析法应用于年平均流量序列突变点识别中,并与传统有序聚类分析法进行对比分析,研究结果表明,改进的有序聚类分析法原理明确,识别突变点更加有效。     

不同降雨插值方法在新疆阿克苏地区降雨插值精度对比中的分析

选取常用两种降雨差值方法对比其在新疆阿克苏地区的降雨插值精度,对比实测降雨数据分析表明:反距离加权插值方法更适用于新疆阿克苏地区降雨插值,其在年尺度和月尺度降雨插值误差明显好于克里金插值方法。研究成果对于新疆阿克苏地区面降水推求,特别是无资料地区降雨计算分析具有参考价值。     

两种常用插值方法在本溪地区降雨插值应用中的对比分析

克里金插值方法和反距离加权插值方法为常用的两种降水插值方法。以辽宁本溪市为研究对象,结合实测降雨数据对比两种常用插值方法在本溪地区降雨插值的适用性。结果表明:相比于反距离加权插值方法克,克里金插值方法年尺度和月尺度降雨插值误差分别降低14. 5%和15. 6%,研究成果对于本溪地区降雨面平均降水分析具有重要的参考价值。     

我国海相火山岩中斜长石的有序度

近20年来,不少岩矿工作者对火成岩中斜长石的有序度做了大量工作,发表了不少文章,但很少涉及海相火山岩的斜长石有序度。笔者测定了四川省拉拉厂铁铜矿区、云南省大红山铁铜矿区、甘肃省白银厂多金属矿区、黑龙江省谢尔塔拉铁矿区和新疆维吾尔自治区雅满苏铁矿区海相火山岩的斜长石有序度。测定的岩石包括细碧岩、磁铁角斑岩、石英角斑岩、石英钠长斑岩、钠长斑岩、钠长变粒岩和角闪钠长片岩。所测岩层的     

Searching for metals in the 1980s

The past four decades have seen an unprecedented development of metal exploration techniques because as exposed and easily exploitable mineral deposits have been used up, exploration geologists have been forced to find new ways of looking deeper into the crust.     

Numerical solution for the dilation of a fluid-saturated porous elastic sphere due to a point source of fluid at the centre of the sphere

Mathematical modelling of the ascent of free fluid through relatively strong rock, deep in the Earth's mantle, presents a challenge in geomechanics. Here the medium is considered as fluid-saturated, porous, elastic and bounded, and the fluid enters at a point source. An explicit finite difference method is developed for the numerical solution to the problem of the dilatation of a fluid-saturated porous elastic sphere due to a point fluid source of constant strength at the centre of the sphere. A cubic spline interpolant is used to evaluate a definite integral which occurs in the boundary condition for the pore fluid pressure at the surface of the sphere. The numerical solutions for the dilatation and pore fluid pressure are compared with analytical solutions and the absolute and relative errors of the numerical solutions are calculated. When the fluid source is switched on, the pore fluid pressure starts to decrease, reaches a minimum value and then steadily increases. The initial time rate of decrease of the pore fluid pressure is independent of the radial distance from the source. It decreases as the radius of the sphere increases and vanishes for a point fluid source in an infinite porous elastic medium.     

嵌入城市：——创造与城市总体环境相融和的广播电视建筑

通过对黄石市广播电视教育中心方案设计过程的总结，提出了广播电视中心的设计既是建筑单体的设计，同时也是城市总体设计的一部分，建筑师应着眼于全局，在展开单体设计之前，应对城市总体规划予以关注，在受到总全规划约束和限定的前提下，应能够将建筑单体恰如其分地 嵌入到城市总体环境当中去。     

Membership List for the year 1922

Those who have followed the historical development of the systematicclassification of the old Palaeozoic rocks in Europe would undoubtedly wellremember how the Ordovician became recognized as a well-defined,independ-     

Searching for long cycles in short sections

Long sedimentary cycles with periods of 400 thousand to two million years are difficult to establish. The main reasons are a lack of stationarity in stratigraphic time series and unknown changes in sedimentation rates. Filtering, trend removal and time scale transformations can help to interpret stratigraphic sequences, but the application of any such method has to be justified by geological arguments. The effects of filtering, scale transformation and trend removal are explored using sets of field data from the Carboniferous (NW Ireland), the Cretaceous (Gubbio, Italy) and Pliocene (Sicily). Their location and stratigraphy are described.     

Searching for silenced voices in Appalachian music

Music is extremely important in representations of place in the Appalachian Region of the United States, where ballads and banjo tunes become musical signposts in popular and academic culture to mark the region’s Otherness. Embedded in the discourse about the region and its music are silences about groups of people that do not fit dominant expectations of authenticity or belonging, the Others within. This essay serves to highlight some historical contributions of these groups, the social processes that have silenced them, and directions for future research to amplify those voices.     

论扬子地台金刚石找矿

扬子地台存在约3 000Ma结晶基底,已发现雪峰期、加里东期两个确切的金刚石成矿期和中、新生代推测成矿期.根据地台周缘存在环状的相关岩带,预示地台中心的川东、重庆地区是探索性寻找金伯利岩的可选地区.要取得较好的找矿效果,还必须在上述地区针对某一成矿期,研究其成矿后抬升剥蚀及沉陷埋藏特征.     

Numerical investigation of pile installation effects in sand using material point method

The installation of displacement piles in sand leads to severe changes in the stress state, density and soil properties around the pile tip and shaft, and therefore has a significant influence on the pile bearing capacity. Most current numerical methods predicting pile capacity do not take installation effects into account, as large deformations can lead to mesh distortion and non-converging solutions. In this study, the material point method (MPM) is applied to simulate the pile installation process and subsequent static pile loading tests. MPM is an extension of the finite element method (FEM), which is capable of modelling large deformations and soil-structure interactions. This study utilizes the moving mesh algorithm where a redefined computational mesh is applied in the convective phase. This allows a fine mesh to be maintained around the pile tip during the installation process and improves the accuracy of the numerical scheme, especially for contact formulation. For the analyses a hypoplastic constitutive model for sand is used, which takes into account density and stress dependent behaviour. The model performs well in situations with significant stress level changes because it accounts for very high stresses at the pile tip. Numerical results agree with centrifuge experiments at a gravitational level of 40 g. This analysis confirms the importance of pile installation effects in numerical simulations, as well as the proposed numerical approach’s ability to simulate installation and static load tests of jacked displacement piles.