Neutron activation studies of the geochemical behaviours of 26 elements in deep-sea drill core sediments from the Indian Ocean

The geochemical behaviours of 26 elements in deep-sea drill core sediments from the Indian Ocean have been investigated with INAA, including Na, K, Ca, Sc, Cr, Fe, Co, Rb, Sr, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au, Th and U. Their distribution patterns with depth are also discussed. In terms of the enrichment factors of the respective elements, their residence times in the sea have been calculated by the least squares fitting and are compared with the previous results.     

河北省峪耳崖金矿床地质地球化学特征

本文从地质地球化学角度对峪耳崖金矿床进行了详细研究,认为该金矿是典型的岩浆热浪型脉状金矿床,金矿与峪耳崖花岗岩(即矿床的主要围岩)为同源岩浆作用的产物,而其源岩物质可能来自深部地壳。黄铁矿中Co/Ni比为1.58,石英中La/Yb比为2.95,δ~(34)S_∑为+2.6‰,δ~(13)O水为+7.03‰,δD为-88.4‰,δ~(13)C为-4.18‰,成矿温度为305～343℃,pH为6.2～6.8,石英包裹体成分中Cl~->F~-、Na~+>K~+,金可能是以Na[AuCl_2],Na[Aucl_4]或Na[AuS]等络合物形式迁移。     

Dielectric constants of BeO,MgO, and CaO using the two-terminal method

Using fused SiO₂, CaF₂, and SrF₂ samples with accurately known dielectric constants, we have evaluated the accuracy and precision of two-terminal dielectric constant measurements on small single crystals using empirically determined edge corrections. Values of κ′ at 1 MHz of 3.836±0.05 for silica, 6.814±0.07 for CaF₂ and 6.463±0.09 for SrF₂ indicate an accuracy and precision of 1.0–1.5% for samples having areas of 0.05–1.0 cm². Dielectric constants of BeO, MgO, and CaO measured by this technique are: BeO, κ′_a=6.87 and κ′_c=7.74; MgO, κ′= 9.90; and CaO, κ′=11.95 where κ′_a and κ′_c are the dielectric constants parallel to the a and c axes, respectively. Dielectric loss measurements on CaO in vacuum between 5–400 K at 10–10⁵ Hz indicate significant dispersion at temperatures higher than 300 K, but the effect of the losses on the dielectric constant is less than 1% at 1 MHz and 300 K.     

由计算机产生的等距离区域分界线

本文介绍一种最近由作者在美国研制的,由计算机产生等距离区域分界线的程序及其数据结构,同时给出初步的试验结果。     

应力波在波阻抗连续变化的弹性杆中的演化

利用特征线方法数值模拟计算了应力波在截面或弹性模量连续变化的弹性杆中的反射,同时也讨论了应力波脉冲宽度对反射波波形特征的影响,其结果对桩基测量有一定的参考价值。     

1991年江淮梅雨暴雨与亚洲季风的关系

利用实际大气参数取值进行尺度分析，求得斜压半地转模式中非线性斜压Ｒｏｓｓｂｙ波的非频散周期解的存在条件与解。给出了能够描述非线性特性波动的无量纲拟能效ε，由此推导了非线性特征波动的波速公式及波参数间的一些诊断关系。     

Structural Styles of the Longmenshan Thrust Belt and Evolution of the Foreland Basin in Western Sichuan Province, China

The Longmenshan thrust system consists of two major groups of structural styles according to the depth of their involvement: basement thrusts-compressional fault blocks; fold-thrust system in the cover. In cross-section, the Longmenshan structural belt is divided into 5 zones. The propagation of the Longmenshan thrust system is piggy-back due to pushing at the early stage and overstep due to gravity sliding at the late stage. Balanced cross-sections and palinspastic reconstruction reveal that the total sliding displacement of the thrust system amounts to 120 km. The tectonic evolution of the Tethys domain in western Sichuan has experienced 5 stages: continental break-up; ocean-continent subduction ; continent-arc collision; orogenic thrusting; uplift of western Sichuan.     

2-D transient soil–surface foundation interaction and wave propagation by time domain BEM

This paper shows an effective implementation of the half-plane Green function for surface strip impulses (Lamb's problem), which was previously developed in a closed form by the authors, into the time-domain boundary element method for the analysis of related initial boundary value problems. The time-stepping algorithm utilizing Heaviside step function makes the solution process free from the Rayleigh wave front singularity. Illustrative analyses performed include that: First, the response due to an impulsive uniform strip loading is dealt with in order to check the accuracy of the present solution and to interpret the associated wave motion in the medium. Second, a rigid massless strip surface foundation is analysed when subjected to various impulsive loadings in vertical, horizontal and rotational directions to observe which wave is most concerned with the respective foundation motion. The field response is also of interest with respect to distance attenuation. Third, the dynamic cross-interaction between active and passive foundations through soil is investigated when multiple strip foundations are placed separately on a half-space with a certain distance.     

Hydrostatic compression of γ-Mg2SiO4 to mantle pressures and 700 K: Thermal equation of state and related thermoelastic properties

P-V-T equations of state for the γ phase of Mg₂SiO₄ have been fitted to unit cell volumes measured under simultaneous high pressure (up 30 GPa) and high temperature (up to 700 K) conditions. The measurements were conducted in an externally heated diamond anvil cell using synchrotron x-ray diffraction. Neon was used as a pressure medium to provide a more hydrostatic pressure environment. The P-V-T data include 300 K-isothermal compression to 30 GPa, 700 K-compression to 25 GPa and some additional data in P-T space in the region 15 to 30 GPa and 300 to 700 K. The isothermal bulk modulus and its pressure derivative, determined from the isothermal compression data, are 182(3) GPa and 4.2(0.3) at T=300 K, and 171(4) GPa and 4.4(0.5) at T=700 K. Fitting all the P-V-T data to a high-temperature Murnaghan equation of state yields: K _TO=182(3.0) GPa, K _TO=4.0(0.3), ?K _T /?T)₀=?2.7(0.5)×10^?2 GPa/K and (?² K _T /?P?T)₀=5.5(5.2)×10^?4/K at the ambient condition.     

1983 年梅雨期前后亚洲季风区水汽输送的分析

分析了1983年江淮流域入梅前、梅雨期以及出梅后垂直积分的水汽输送和水汽通量散度分布,计算了南海和中国东部地区的水汽收支。结果指出:江淮流域入梅前,华南地区降水的水汽主要来自印度西南季风和东南季风气流;梅雨期降水的水汽主要来自印度西南季风气流;出梅后华北雨季则主要受中低纬水汽输送气流汇合的影响。分析表明,江淮流域梅雨期是印度西南季风气流加强并东进北上,西太平洋高压东撤所造成的;而梅雨结束则是由于西南季风气流减弱西退和西太平洋高压西进北上所造成的;此外,还讨论了水汽输送、水汽通量辐合与云量及我国东部降水的关系。