A perturbation boundary integral equation method for analysis of interaction between foundation and nonlinear rock and soil medium

A scheme is developed for analysing the interaction between a foundation and a nonlinear rock and soil medium, in which the foundation is considered as a linear elastic body and a typical boundary integral equation method (BIEM) is employed. On the basis of taking the nonlinear properties of the medium into account, a perturbation BIEM is developed. The fundamental equations for the nonlinear coupling analysis are formulated, and typical problems are solved and discussed by the present method.     

The role of analytical chemistry in Niger Delta petroleum exploration: A review

Petroleum and organic matter from which the petroleum is derived are composed of organic compounds with some trace elements. These compounds give an insight into the origin, thermal maturity and paleoenvironmental history of petroleum, which are essential elements in petroleum exploration. The main tool to acquire the geochemical data is analytical techniques. Due to progress in the development of new analytical techniques, many hitherto petroleum exploration problems have been resolved. Analytical chemistry has played a significant role in the development of petroleum resources of Niger Delta. Various analytical techniques that have aided the success of petroleum exploration in the Niger Delta are discussed. The analytical techniques that have helped to understand the petroleum system of the basin are also described. Recent and emerging analytical methodologies including green analytical methods as applicable to petroleum exploration particularly Niger Delta petroleum province are discussed in this paper. Analytical chemistry is an invaluable tool in finding the Niger Delta oils.     

Fourier transform spectroscopy of CH3OH: rotation-torsion-vibration structure for the CH3-rocking and OH-bending modes

High-resolution Fourier transform spectra of CH₃OH have been investigated in the infrared region from 930 to 1450 cm⁻¹ in order to map the torsion-rotation energy manifolds associated with the ν₇ in-plane CH₃ rock, the ν₁₁ out-of-plane CH₃ rock, and the ν₆ OH bend. Upper-state term values have been determined from the assigned spectral subbands, and have been fitted to power-series expansions to obtain substate origins and effective B-values for the three modes. The substate origins have been grouped into related families according to systematic trends observed in the torsion-vibration energy map, but there are substantial differences from the traditional torsional patterns. There appears to be significant torsion-mediated spectral mixing, and a variety of “forbidden” torsional combination subbands with |Δυ_t|>1 have been observed, where υ_t denotes the torsional quantum number (equivalent to υ₁₂). For example, coupling of the (υ₆,υ_t)=(1,0) OH bend to nearby torsionally excited (υ₇,υ_t)=(1,1) CH₃-rock and (υ₈,υ_t)=(1,1) CO-stretch states introduces (υ₆,υ_t)=(1,0)←(0,1) subbands into the spectrum and makes the ν₇+ν₁₂−ν₁₂ torsional hot band stronger than the ν₇ fundamental. The results suggest a picture of strong coupling among the OH-bending, CH₃-rocking, and CO-stretching modes that significantly modifies the traditional energy structure and raises interesting and provocative questions about the torsion-vibration identity of a number of the observed states.     

Measurements of saturated basic and acidic rock electrical conductivities at lower crustal temperatures and high pressures

Abstract

Laboratory measurements of the electrical conductivity of brine saturated acidic and metabasic rocks were done at confining pressures up to 0.2 GPa, high pore pressures and temperatures of 900°C. Acidic rocks showed conductivities insufficient to explain the lower crustal high conductivity layer. Basic rocks, however, showed conductivities consistent with the high conductivity layer at those temperatures that the layer is thought to possess.     

The Determination of 222Rn in Drilling Fluids of the KTB Pilot Borehole Using SSNTD Techniques

²²²Rn dissolved in drilling fluids of the KTB (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland) pilot hole has been determined using solid state nuclear track detector (SSNTD) technique:The α-sensitive SSNTD CR-39 was used to measure the a-activity of ²²²Rn. Well-defined conditions for Rn-measurements could be established by employing a mica nuclear track microfilter to separate the detector containing air volume from the volume containing the water. This technique has been applied to determine quantitatively the ²²² Rn-concentration as a function of depth of the borehole down to 4000 m.     

耦合时间精度对模拟飞行器自由运动特性的影响

将亚迭代技术引入流体动力学和刚体动力学方程的耦合求解,获得细长三角翼极限环运动的规律.探讨耦合时间精度对飞行器非定常运动特性的影响,细长三角冀的大迎角自由滚运动最终形成极限环振荡的周期性自维持运动,不同攻角自由滚振幅阶跃式的变化特点较好地吻合了自由滚试验的规律.对于多系统耦合问题,亚迭代耦合求解(耦合时间精度为二阶)对物理时间步长的依赖性不明显;而存在一阶时间滞后的解耦推进方法的数值结果强烈地依赖于物理时间步长选取,稍大的时间步长将导致非物理的数值结果.     

分形(fractal)几何与岩石断裂

岩石断口的不规则性可以统计地认为具有自相似性,由此本文应用新几何——分形(fractal) 几何来描述这种不规则性。建立了穿晶以及沿晶界和穿晶相偶合的微观断裂fractal 模型,用电镜和光学显微镜观察了大量岩石断口的 fractal 特征,得到了 fractal 维数与岩石宏观断裂力学量之间的初步对应关系。     

中国东南部中、新生代基性岩荧光光谱与等离子质谱测试结果对比及其地质意义分析

通过对中国东南部中、新生代基性岩类岩石的荧光光谱和等离子体质谱分析结果的对比研究,发现中生代基性岩SiO₂平均含量为±50%,新生代基性岩为±43%,前者属典型基性岩类,后者属超基性岩类。两者在微量元素及稀土元素组成上也有显著差异。中生代基性岩的微量元素和稀土元素标准化配分模式与上陆壳的配分模式相同或相似,而新生代基性岩则与OIB型洋岛玄武岩相同或相似。由此得到的认识是：新生代的基性岩与OIB型洋岛玄武岩一样,均为地幔来源,而中生代的基性岩浆则极有可能来自上陆壳底部,与本区中生代壳内重熔岩浆层的演化有关。     

Rocky coast processes: with special reference to the recession of soft rock cliffs

Substantial progress in research on the recession of coastal cliffs composed of soft materials has been made in recent years and data with higher accuracy have been accumulated. This paper provides the state of the art review in the recession studies and highlights two new findings obtained from the reanalysis of existing data. The review topics are: episodic and localized nature of cliff recession; the development of cliffline; the relationship between cliff height and recession rate; mechanisms of cliff toe erosion by waves; a fundamental equation for wave-induced toe erosion; factors controlling toe erosion; and slope instabilities and mass movements. The findings are presented on (1) the temporal change in cliffline recession mode and (2) the effect of beach sediment at the cliff base on the cliff erosion.     

激光诱导击穿光谱技术对火成岩岩性的高精度识别

在石油勘探领域,细碎岩屑样品的岩性识别,特别是物性接近的火成岩的高精度识别是地质学的难题之一。针对这一问题,提出了一种基于激光诱导击穿光谱技术(LIBS)元素分析和全碱-硅(TAS)图版的新方法。利用自主搭建的LIBS系统,首先通过对比实验,系统的研究了脉冲能量、采集延时、采集方式、预燃对光谱信号的影响,确定了对火成岩样品元素分析的最佳条件：脉冲能量50 mJ,采集延时2 μs,采集同一样品表面20个不同点的光谱积分平均,并通过实验证明了预燃的样品处理方式不适合火成岩样品,有效提高了样品检测光谱数据的重复性。随后确定了火成岩岩性识别常用7种元素(钠镁铝硅钾钙铁)的特征谱线,定性分析和比较了不同岩性的火成岩样品;利用已知元素含量的国标系列岩石样品信息,生成了钠、硅、钾的定标曲线,线性相关系数均大于0.9,并利用国标岩石样品考察了定量分析的准确性;利用定标曲线法定量分析了火成岩样品的元素含量,并采用TAS图版法识别火成岩的岩性,准确率达90.7%。研究表明,LIBS技术能够有效实现火成岩岩性的高精度识别。