裂隙型硬粘土的力学模型及其在边坡工程中的应用

硬粘土是介于软岩和硬土之间的一种介质, 其中含有规律分布的裂隙, 具有明显的方向性和各向异性特征; 本文从实际应用的角度出发, 提出一种适用于裂隙性硬粘土的损伤力学模型, 并应用于南水北调中线渠道边坡工程的数值模拟分析。     

粘土矿物钝化改性及岩土的力学性质

本文以自行研制的粘土矿物钝化剂对广东省和武汉市等六地区的土壤进行了钝化改性实验研究，并对钝化效果的影响因素做了初步的分析探讨。实验表明，虽然6个地区11个样品中的粘土矿物种类和含量不同，但钝化剂对所有样品都有稳定的作用。其稳定效果，不仅与样品的物相组成和粒度分布有关；而且还与粘土矿物的种类及其含量密切相关。就三种主要粘土矿物来说，钝化效果的顺序是高岭土＞伊利石＞蒙脱石。     

The distribution of acetaldehyde in the lower troposphere during TROPOZ II

A series of 72 measurements of the acetaldehyde (CH₃CHO) mixing ratio were made in the lower troposphere during TROPOZ II. These measurements are the first ever made of the background level of this trace gas in the free troposphere. The data show a vertical decrease of the CH₃CHO mixing ratio with increasing altitude and indicate higher CH₃CHO concentrations in the Northern Hemisphere — in general agreement with a model-derived average CH₃CHO distribution. Deviations of the observed CH₃CHO mixing ratios from the modelled mean distribution are correlated with similar deviations in the corresponding HCHO mixing ratios.     

Experimental and theoretical determination of concentration profiles and influence of particle characteristics in blowing snow

Snow drift transport may cause avalanches on the roads during the periods of snowfall and strong wind. To better understand the factors influencing transport we have developed a theoretical model. This model is based on the boundary layer theory, where the particle mass conservation is considered. Assuming that the saturation is reached, the concentration profile can be represented by a negative exponential law. By means of this analysis, the influence of particle characteristics is explored through the roles of threshold friction velocity and fall velocity. Using fluid mechanics laws, an analysis of the concentration profile resulting from the effect of the wind on a particle bed was also developed. For several velocities of flow and for different kinds of particles an experimental determination of the concentration profile was achieved. We used a laser visualisation and image processing technique to carry out these experiments. The obtained results fit with the values predicted by the theoretical model.     

The NO2 absorption spectrum. I: Absorption cross-sections at ambient temperature in the 300–500 nm region

New laboratory measurements of NO₂ absorption cross-sections have been performed between 300 and 500 nm at ambient temperature with improved experimental conditions: low gas pressures, long absorption paths, suitable absorbance values, narrow spectral bandwidths. The data, stored at 0.01 nm intervals, have been compared to those of the more recent studies and some reasons of disagreement are discussed.In the photolysis region below 400 nm, our absorption cross-sections are larger than those previously published, suggesting that the photodissociation coefficient calculated from the current data sets is underestimated. In the structured region of the spectrum above 400 nm, improvement of the resolution gives more precise values useful for optical measurements in atmosphere.Unité de Recherche Associée au CNRS.     

云南梅树村前寒武系-寒武系界线剖面硅同位素研究

云南梅树村前寒武系-寒武系界线剖面是研究前寒武系-寒武系界线层型最重要的国际候选剖面之一。本文首次系统地研究了硅同位素在剖面中的变化规律,指出“C”点附近“界线粘土层”为火山成因,“B”点至“C”点之间有海底喷气活动;“C”点附近的δ~(13)C,δ~(18)O负异常与生物大量活动有关,而非“灾变”所致。     

塔克拉玛干沙漠及其以南风成相带划分和认识

至少在末次冰期初，塔克拉玛干沙漠及其以南就已存在风成的砂丘砂、亚砂土和黄土岩相带。末次冰期以来的全球冷期中，造成砂丘砂、亚砂土和黄土沉积的ＮＥ和ＮＷ风系及其影响下的风力未有显著变化，因此，这几个风成相带沉积界线亦没有明显移动。自那时以来的全球暖期，塔克拉玛干和其南部，气候暖干，导致四周山地冰雪大量消融，于本区形成冲积，洪积。然而，冲洪积作用并未能改变风成相带分布的基本格局。     

时段平均输沙率计算方法探讨

以流量和含沙量在时段内呈线性变化，而输沙率应是二次函数为出发点，用积分的方法推导出时段平均输沙率的计算公式，认为采用这套公式计算日平均输沙率和日平均小于某粒径沙重百分数是合理和实用的。可以提高成果的准确性。     

生物中碳氢化合物的结晶（英文）

文章专门讨论与特定成岩作用伴生的铬、铂和硫化物矿床形成的内生因素。该类成岩作用对矿石富集有显著影响。矿床的巨大规模起因于与广泛强烈的成岩过程有关的特殊的成矿作用。这些作用导致产在超基性杂岩中的特殊纯橄榄岩（铬矿石）、基性超基性层状侵入体中的低硫层和铁镁橄榄石纯橄榄岩（铂族金属矿床）的形成,以及富铁火成分异岩的透岩浆硫化作用（Ｃｕ Ｎｉ硫化物和Ｃｕ Ｚｎ Ｐｂ硫化物矿石）。还根据巨型矿床的成因模型提出了矿物学岩石学的找矿标志     

秋冬季节珠三角典型区域气溶胶浓度垂直分布的激光雷达反演

气溶胶与全球热辐射平衡、水循环、人类健康密不可分,其观测精度直接影响天气预测、气候建模以及对人类健康影响评估的精度,激光雷达能监测气溶胶的垂直分布,对污染气溶胶的扩散趋势、污染源反演、气候预测等均有重要意义。本文基于激光在大气中的辐射传输过程,根据米散射激光雷达的工作原理,使用雷达的多个系统参数计算雷达常数,建立激光雷达气溶胶质量浓度反演模型,从地面向上在晴空条件下进行了珠三角地区典型区域的秋冬季节气溶胶垂直观测的实验,计算气溶胶质量浓度的垂直廓线,反演气溶胶的垂直分布情况。验证与分析结果表明:(1)激光雷达反演结果显示,白天的反演结果中噪声大大减少,表明反演算法能够有效减弱太阳光的影响。(2)相比于传统方法,使用雷达常数而非边界值的反演结果波动较小,更符合实际,能够有效避免高空噪声的影响。(3)高层大气在晴朗静稳天气状况下较为干净,气溶胶基本分布在低空区域,质量浓度随高度基本呈负指数分布。