Preliminary study on the mode of occurrence of arsenic in high arsenic coals from southwest Guizhou Province

Coal samples from high arsenic coal areas have been analyzed by electron micropbe analyzer (EMPA), scanning electron microscopy with an energy dispersive X-ray analyzer (SEM-EDX), X-ray diffinction analysis (XRD), low temperature ashing (LTA), transmission electron microscopy (TEM), X-ray absorption fine structure (XAFS), instnunent neutron activation analysis (INAA) and wet chemical analysis. Although some As-bearing minerals such as pyrite, arsenopyrite, realgar (?), As-bearing sulfate, and As-bearing clays are found in the high arsenic coals, their contents do not account for the abundance of arsenic in the some coals. Analysis of the coal indicates that arsenic exists mainly in the form of A_s ⁵⁺ and A_s ³⁺, combined with compounds in the organic matrix. The occurrence of such exceptionally high arsenic contents in coal and the fact that the arsenic is dominantly organically associated are unique observations. The modes of occurrence of arsenic in high As-coals are discussed.     

Determination of the absolute32S/34S ratio of IAEA-S-1 reference material and V-CDT sulfur isotope standard

The absolute³²S/³⁴S ratios of IAEA-S-1 reference material and V-CDT standard are determined. For cross-checking, two sets of synthetic isotope mixtures are prepared from high purity³²S and³⁴S-enriched materials in different forms: the first set is prepared from BaSO₄ whereas the second is prepared from Ag₂S. The sulfur isotope analyses are done by using SF₆ method with a MAT-251 EM mass spectrometer. The resulting³²S/³⁴S ratio of IAEAS-1 reference material is 22. 656 4 ±0.006 0, and that of V-CDT is 22.649 6 ± 0.006 0. Project supported by the National Natural Science Foundation of China (Grant No. 86020341).     

琅琊山抽水蓄能电站上水库副坝地段岩溶发育特征及渗漏分析

琅琊山抽水蓄能电站上水库位于岩溶区,水库的主要问题是副坝坝基深部的岩溶渗漏问题。本文简要分析副坝地段岩溶发育规律和特征,利用地下水渗流场分析岩溶渗漏特征和形式,并用岩溶管道水汇流理论分析和计算渗漏量,从而分析研究岩溶结构体的透水性,为岩溶渗漏分析和防渗处理提供依据      

地形与积云对流对重力惯性波不稳定增长的影响

利用一个带有地形的二层均质流体模式,引入参数化形式的积云对流加热反馈,研究了重力惯性波的不稳定增长及传播,得到并讨论了一些接近天气实际情况的结果。      

热带东风急流的气候学和中期振荡

本文用13年夏半年(5—10月)月平均风场和两年逐日风场资料研究了200hPa南亚热带东风急流的气候学特征和中期振荡过程。研究表明,南亚夏季热带东风急流显著的非季节性变动和年际差异与低纬对流层高层大尺度环流变化和南亚夏季风活动密切相关,相对于多年平均而言,存在5类异常的东风急流。 各种分析表明,热带东风带存在三种主要的中期振荡。准50天周期振荡与夏季南亚对流层上部大尺度散度场的变化相关联,表现为十分显著的向南的位相传播。准50天和25天振荡均存在显著的年际变化。准50天周期振荡系统性不强的年份,准25天周期振荡是低纬行星波的主要振荡,在东风急流区除表现为系统性向西传播外也表现为向南的位相传播。准双周振荡在东风带一般向西传播。      

三种岩溶塌陷形态的产生条件

本文对三种岩溶塌陷形态─—塌井、地面下沉和地面裂缝的产生条件进行了分析。为解释直径很大的塌井,提出“组合塌井”概念。地面下沉可理解成土体下沉量很小而直径特大的“组合塌井”．而地面裂缝则是地面下沉的伴生产物。      

以声发射估计岩石试样先存应力的新方法

利用声发射话动的凯塞（Kaiser）效应测定岩石先存最大应力已成为声发射技术的重要应用领域。目前,判断岩石凯塞效应对应应力的方法仍被重视。作者在研究岩石在单轴压缩条件下的声发射话动时发现:除了通过凯塞效应可测定岩石的先存最大应力之外,还可根据重复加载时声发射话动的某些特点推断出加载前的先存最大应力,从而进一步验证和提高了利用凯塞效应测定先存最大应力的可靠性。重复加载时声发射话动在一定技术条件下会出现这样的特点:在应力达到第一次加载的最大应力值时出现凯塞效应;而在此之前,当应力达到加载前岩石的先存最大应力值时,声发射话动相对其前后有所特殊。作者认为,这种现象可能反映了材料对先前经历过的损伤的记忆能力。本文初步探讨了这一现象的物理基础。     

人影高炮作业落区的一种判定方法

提出了人影高炮弹丸轨迹的运动方程,根据方程计算理论弹丸落点并得出安全区外扩的误差范围。针对人影高炮作业射界设定安全区的情况,提出落点位于安全区内外的判定方法,从而在理论上给出判断人影高炮作业安全性的问题。     

Numerical study of harbor oscillations induced by water surface disturbances within harbors of constant depth

Oscillations within an enclosed rectangular harbor and a set of partially opened rectangular harbors with various widths and locations of entrance induced by cubic water surface disturbances with different initial heights and locations are simulated using FUNWAVE 2.0 model. The height and the location of the cubic water surface disturbance refer to its thickness and its relative horizontal position inside the harbor, respectively. The water depth inside and outside all harbors is set to be constant. The aim of this paper is to investigate how different heights and locations of the water surface disturbance and various widths and locations of harbor entrance affect the oscillations inside the harbor. Results show that for the given harbors and the range of the initial height of water surface disturbance studied in this paper, all the response amplitudes of various eigenfrequencies increase linearly with the initial height of water surface disturbance. The variations of the initial location of water surface disturbance along the backwall and sidewall of the harbor can significantly change the transverse and longitudinal oscillation patterns of various modes, respectively. The effects of the variations of the width and location of the harbor entrance on the response amplitudes of various resonant modes both depend on the relative positions of their node lines and antinode lines to the harbor entrance.     

Effect of uneven noise source and/or station distribution on estimating the azimuth anisotropy of surface waves

With the development of the dense array, the surface wave velocity and azimuthal anisotropy under the array can be directly obtained by beamforming the noise cross-correlation functions (NCFs). However, the retrieval of the Green's function by cross-correlating the seismic noise requires that the noise source has a uniform distribution. For the case with uneven noise source, the azimuthal dependence on the sources in the expression for the spatial coherence function, which corresponds to the NCF in the time domain, has the same form as the azimuthal dependence of the surface wave velocity in weakly anisotropic media. Therefore, the uneven noise source will affect the surface wave anisotropy extraction. In this study, three passive seismic methods, i.e., beamforming, SPAC (spatial autocorrelation), and NCF, are compared to demonstrate that an uneven source distribution and uneven station distribution have equivalent effects on the outcome from each method. A beamforming method is proposed to directly extract the velocity and azimuthal anisotropy of surface waves. The effect of uneven noise source and/or station distribution on estimating the azimuth anisotropy of surface waves was investigated using data from the ChinArray Phase II. A method for correcting the apparent anisotropy in beamforming results caused by an uneven station distribution is suggested.