地下卤水体系中水活度的计算方法评定

在温度 1 2 .1～ 60 .5℃范围内测定了地下卤水体系的饱和蒸汽压 ,并采用Clausius -Clapeyron方程进行关联 ,计算水活度 ;比较强电解质混合体系水活度的理论计算模型 ,探索计算地下卤水体系水活度的最佳方法     

基于最近邻支撑向量特征线融合算法的核爆地震识别

为增强核爆地震模式分类器的泛化能力以提高对核爆炸事件的准确识别能力,论文提出了一种选择支撑向量样本集来表征训练样本集的最近邻支撑向量特征线分类算法,用以训练时扩展核爆地震的训练样本库,提高分类器的泛化能力.该算法用于核爆炸和地震的识别结果发现,和最近邻特征线分类器相比,提出的算法降低了计算复杂度,但识别能力却有些许降低.对新算法的分析发现,纯粹的支撑向量集不能完全代表原始样本空间集,支撑向量比例在其中有重要作用,为发挥支撑向量比例的作用以提高核爆分类器的识别能力,提出了最近邻支撑向量特征线融合算法.最后以核爆地震数据库对上述算法进行了检验和分析,理论分析和识别结果证实,在相同的训练样本选择条件下,最近邻支撑向量特征线融合算法对于核爆炸的识别来说具有较好的泛化能力,正确识别率达到90.3%,且优于支持向量机算法和最近邻特征线算法.     

Considering dynamic soil structure interaction (SSI) effects on seismic isolation retrofit efficiency and the importance of natural frequency ratio

This paper utilizes and expands on existing coupled BEM–FEM (finite element method) methods for the investigation of the effects of soil structure interaction (SSI) on both an un-retrofitted and seismically isolated typical bridge structure. A simple numerical model of the bridge and surrounding soil is formulated and excited by an earthquake excitation. Utilizing Newmark's β FEM solution method along with the closed form B-spline BIRF method, the structural damped period, composite damping ratio, pier relative displacement, and base shear demand are monitored. From these results, the effects of SSI on this structure are identified. Additionally, the importance of the relative rigidity between the soil-foundation system and the bridge structure is also investigated. The results of the studies indicate that the response of the complete structure system considered is affected by the inclusion of SSI effects. Furthermore, the efficiency of the isolation measures designed using fixed base conditions is decreased by considering SSI over a certain relative rigidity range that is quantified using the structure to soil-foundation natural frequency ratio.     

新疆测震台网记录的远距离工业爆破分析

对新疆测震台网数字化记录中的宁夏ML4．4爆破记录进行了分析,新疆台网大部分台站都能记录到上千公里ML4.0以上的工业爆破。又对新疆巴里坤地震台记录的约1200km的宁夏ML3．8、内蒙ML4．2地震和宁夏ML4．4的工业爆破记录进行了分析,发现近距离爆破记录的特征大部分可以在远距离爆破中找到。     

Comparison of nitrate attenuation characterization methods at the Uranium mill tailing site in Monument Valley, Arizona

Several methods for characterizing the occurrence and rate of nitrate attenuation were tested at a field site near Monument Valley, Arizona. Spatial and temporal nitrate concentration data collected from a transect of monitoring wells located along the plume centerline were analyzed to evaluate the overall rates of natural attenuation. The occurrence and rate of denitrification was evaluated through microcosm experiments, nitrogen isotopic fractionation analysis, and solute-transport modeling. First-order denitrification-rate coefficients calculated with each method were comparable. In addition, the composite natural attenuation rate coefficient was similar to the denitrification-rate coefficients, which suggests that microbially induced decay primarily controls nitrate attenuation at the site. This research highlights the benefits associated with a multiple-method approach for the characterization of natural attenuation.     

地震和爆破时频域能量分布特征的对比分析

运用小波分析方法计算和分析了CDSN乌鲁木齐台记录的天然地震和人工爆破在时频域的能量分布特征,分析结果表明,在震中距大致相同的范围内,同一台站记录的不同当量的人工爆破具有相似的时频变化规律,而天然地震能量分布却存在较大差别。天然地震与人工爆破的时频域能量分布谱图存在比较明显的差异。     

4A沸石分子筛对KNO3和NH4NO3的吸持作用

实验研究了4A沸石分子筛经熔融盐处理后对KNO₃和NH₄NO₃的吸持作用。结果表明：在实验条件下,KNO₃处理后的4A沸石中含钾(以K₂O计)15.01%,含NO^-₃ 9.23%;NH₄NO₃处理后的4A沸石中含NO^-₃ 10.78%,含NH⁺₄ 0.94%。熔融盐处理后的样品X射线衍射峰相对强度发生了变化,红外光谱中1 640 cm^-1附近水的吸收带强度减弱,1 390 cm^-1附近出现的NO^-₃离子的强吸收带及825 cm^-1附近出现的NO^-₃离子的弱吸收带,以及热重-差热曲线中KNO₃和NH₄NO₃的热失重和分解热效应均证明沸石中吸持盐的存在。处理后4A沸石分子筛的基本骨架结构没有被破坏,吸持盐的4A沸石对营养盐的储备大大提高,是潜在的缓释肥料。     

Narrating the Natural History Unit: institutional orderings and spatial strategies

This paper develops a conceptualisation of institutional geographies through participation observation and interviews in the BBC’s Natural History Unit (NHU), and the approach of actor network theory. The methodological and theoretical tenets of actor network theory are examined for the insights they offer for understanding the achievements of this pre-eminent centre for the production of natural history films. The scope, scale and longevity of the NHU are analysed through the means by which localised institutional modes of ordering extend through space and over time. Drawing on empirical material, the paper outlines three different modes of ordering, which organise relations between actors in the film-making processes in different ways: prioritising different kinds of institutional arrangements, material resources and spatial strategies in the production of natural history films. Through these three modes of ordering, and through the topological insights of actor network theory, a series of overlapping and interlinked institutional geographies are revealed, through which the identity of the Unit as a centre of excellence for wildlife film-making is performed.     

非金属矿物在抗菌材料中的应用

对以非金属矿物沸石、蒙脱石等为载体的金属离子型无机抗菌剂的研 究作了简要介绍,并讨论了利用天然非金属矿产资源研制开发抗菌剂中应注意的问题。     

Application of neural networks in natural periods identification and simulation of prefabricated buildings response

The paper deals with an application of neural networks for detection of natural periods of vibrations of prefabricated, medium height buildings. The neural network technique is also used to simulate the dynamic response at selected floor of one of the analysed buildings subject to seismic loading induced by explosives in a nearby quarry. Both the training and testing patterns were formulated on the basis of measurements performed on actual structures. The results of neural network identification of natural periods of the considered buildings obtained with different soil, geometrical and stiffness parameters are compared with the results of experiments. The application of back-propagation neural networks enables us to identify the natural periods of the buildings with accuracy quite satisfactory for engineering practice. The experimental and generated data of vibration displacements are compared and much clearer comparison is given on the phase plane: displacements versus velocities. It was stated that a good generalization takes place both with respect to displacements and velocities.