我国西北地区不同类型纤蛇纹石石棉的电镜研究

作者对西北地区不同类型温石棉矿床的石棉进行了扫描电镜和高分辩率透射电镜研究,拍摄到清晰的晶格象和电子显微象,发现茫崖型和小八宝型的温石棉纤维的晶格条纹、晶格缺陷及纤维形貌有明显差异。这种差异与成棉地质条件和温度有关。     

灵武四次中强地震前地下水动态

宁夏灵武在37个月内发生了4次中强地震和数千次小余震。这4次地震震级相差不大,震中基本在同一地点,其地点均在银川平原地震地下水动态观测网范围内。4次中强地震前,水氡、水位动态反映各异,即使同一井泉,在不同地震前的短临异常反映也不相同,这一现象揭示了地震前兆的复杂性和特定条件下的不重现性特征。     

数字地形模型自动获取的一种新方案——辐射法

利用数字影像自动提取数字地形模型(DTM)的关键是影像匹配。匹配算法有基于特征的相关匹配和基于影像区域匹配两类,前者利用某种抽象的“特征”(一般为线段或点),而后者直接比较像素。但要同时满足DTM的精度,密度、可靠性和速度等要求,单纯引用某种特定的相关方法是不能有效地解决生产实际问题的。本文在分析现有几种典型方法的基础上,提出了基于特征点的辐射法,从而较为合理地兼顾了精度、密度、可靠性以及速度等指标。在AST 386微机上,无任何加速处理器,运行速度达到每秒1～3点,精度为子像素精度。     

Strong site preference of Co2+ in olivine,Co1.10Mg0.90SiO4

The crystal structure and site preference of Co²⁺ in a synthetic Co_1.10Mg_0.90SiO₄ olivine have been determined from single crystal X-ray diffraction data collected on an automatic diffractometer. The R factor is 0.044 for 612 reflections. The site occupancies are: Ml site: Co 0.730±0.006; Mg 0.270; M2 site: Co 0.370, Mg 0.630. The Gibbs free energy change, ΔG° for the ion-exchange reaction between M1 and M2 sites is ?4.06 kcals/mole, assuming ideal mixing at each set of sites. This energy may be called ‘site preference energy’ of Co²⁺ in olivine. The strong preference of Co²⁺ for the M1 site can be quantitatively explained by two competing forces: preference of ions larger than Mg²⁺ for the M2 site and stronger covalent bonding of transition metal ions at the M1 site. For Fe²⁺, Mg²⁺, these two effects nearly neutralize each other, explaining the lack of considerable cation-ordering in Fe-Mg olivines.     

构造活动和火山作用对干酪根成烃转化的影响

盆地构造活动和火山作用可以促进干酪根的成烃转化。构造活动的影响表现在力化学作用上；火山活动的影响除了表现为加热作用外，还表现为与火山岩有关的矿物与有机质或干酪根的相互作用，包括催化和加氢作用。黄铁矿被证明是一种更有效的催化剂。这些影响是附加在正常的干酪根热解作用上，而且构造活动和火山作用的影响也是复合在一起的。一些模拟实验证实了上述作用的存在以及对于不同的干酪根类型所施加影响的程度是不同的。     

Dynamic analysis of structures using modified Lanczos co‐ordinates

An efficient dynamic analysis method using the modified Lanczos co‐ordinates is presented. The proposed method is obtained by applying the modified Lanczos algorithm using Lanczos vectors that satisfy the stiffness‐orthonormality condition to the conventional Lanczos co‐ordinates method. The modified Lanczos co‐ordinates method is more efficient than the conventional method in the case of structures under multi‐input loads. The effectiveness of the modified Lanczos co‐ordinates method is verified by analysing a numerical example. Copyright © 2003 John Wiley & Sons, Ltd.     

基础隔震结构随机地震响应分析的复模态法

本文对多自由度基础隔震结构的随机地震响应问题进行了系统研究，首先建立了运动方程，然后用第一振型将上部结构展开，针对所得方程为非经典阻尼、非对称质量和非对称刚度情况，用复模态法解耦，获得了以第一振型表示的结构地震响应的解析解，对单自由度体系，此解即为结构响应的精确解，从而建立了两自由度体系在任意非经典阻尼与非对称质量和刚度情况下随机地震响应解析解分析的一般方法。本文方法也可用于带TMD减震结构、无损伤“加层减震”加固结构的随机地震响应分析与优化设计。     

鞍山中太古代铁架山花岗岩中表壳岩包体的地球化学特征及地质意义

鞍山地区中太古代铁架山花岗岩中存在多种类型的表壳岩包体。本文对其中 类变泥砂质岩石进行了研究。一类包括云母石英片岩、黑云变粒岩、浅粒岩, 它们高钾低钠, 具有强的负铕异常(Eu/Eu^* = 0.10~0.23) 和负钡异常(Ba/Ba^*＝^*＝0.09～0.23),t_DM和ε_Nd(3.0 Ga)变化范围分别为3.36～3.51 Ga和-3.89～-1.59.岩石高的成熟度和长的地壳滞留时间表明鞍山地区中太古代以前陆壳基底就有了相当的规模,并具有很长的地壳演化历史.它们在元素组成上与铁架山花岗岩十分相似,相互间存在物源上的成因联系.铁架山花岗岩的t_DM和ε_Nd(3.0 Ga)变化范围分别为3.39～3.70 Ga和-4.99～-2.36,Sm、Nd同位素组成与变质泥砂质岩石存在一定差异,看来主要与前者形成过程中源区选择性部分熔融和稀土组成发生变化有关.另一类为黑云斜长片麻岩,组成上与第一类变泥砂质岩石存在较大区别,而与古太古代陈台沟花岗岩较为相似,相互间可能存在物源上的成因联系.它们对铁架山岩体部分轻、重稀土强烈分离花岗质岩石的形成可能起了一定作用.物源区的复杂性是铁架山花岗岩组成上存在较大变化的主要原因.     

Distribution and Variation of Ribonucleic Acid （RNA） and Protein and Its Hydrolysis Products in Lake Sediments

Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition —amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein. The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities. The research project was financially supported jointly by the Ntional Natural Science Foundation of China (No. 40173038) and the Guizhou Provincial Foundation (No. 3090) and the Chinese Academy of Sciences Knowledge-Innovation Foundation (KZCX2-105).     

Geochemical evolution of highly alkaline and saline tank waste plumes during seepage through vadose zone sediments

Leakage of highly saline and alkaline radioactive waste from storage tanks into underlying sediments is a serious environmental problem at the Hanford Site in Washington State. This study focuses on geochemical evolution of tank waste plumes resulting from interactions between the waste solution and sediment. A synthetic tank waste solution was infused into unsaturated Hanford sediment columns (0.2, 0.6, and 2 m) maintained at 70°C to simulate the field contamination process. Spatially and temporally resolved geochemical profiles of the waste plume were obtained. Thorough OH⁻ neutralization (from an initial pH 14 down to 6.3) was observed. Three broad zones of pore solutions were identified to categorize the dominant geochemical reactions: the silicate dissolution zone (pH > 10), pH-neutralized zone (pH 10 to 6.5), and displaced native sediment pore water (pH 6.5 to 8). Elevated concentrations of Si, Fe, and K in plume fluids and their depleted concentrations in plume sediments reflected dissolution of primary minerals within the silicate dissolution zone. The very high Na concentrations in the waste solution resulted in rapid and complete cation exchange, reflected in high concentrations of Ca and Mg at the plume front. The plume-sediment profiles also showed deposition of hydrated solids and carbonates. Fair correspondence was obtained between these results and analyses of field borehole samples from a waste plume at the Hanford Site. Results of this study provide a well-defined framework for understanding waste plumes in the more complex field setting and for understanding geochemical factors controlling transport of contaminant species carried in waste solutions that leaked from single-shell storage tanks in the past.