Adsorption characteristics of perchloroethylene in natural sandy materials with low organic carbon content

Laboratory batch tests were conducted to investigate the sorption isotherms and sorption kinetics of the chlorinated hydrocarbon perchloroethylene (PCE) in five natural sandy materials with an organic carbon content (f _oc) in the range 0.080–0.540%. The amended non-linear dual-mode model can describe the sorption isotherms in materials with f _oc in the range 0.080–0.090%. For a sample with a much higher f _oc of 0.54%, the absorption isotherm was found to fit a linear model. These results may indicate that organic carbon is not the main factor influencing the sorption isotherm. The sorption kinetics of PCE in samples with f _oc in the range 0.080–0.090% are not first-order and are different from those observed in the samples with higher f _oc. The sorption process in the materials with lower f _oc involves fast sorption, fast desorption and an equilibrium stage. The results may imply that the factors affecting sorption kinetics of PCE in low f _oc media are pore filling and capillary condensation rather than organic carbon content.     

广东省某水电站上坝公路、进厂房公路地质灾害影响评估

通过对广东省某水电站公路两侧存在的地质灾害-滑坡进行稳定性分析,并结合区域地质情况对该电站上坝公路、进厂房公路两侧存在的地质灾害现状进行了评估;最后,对评估区进行了分区,同时针对不同分区提出不同的治理方案.     

Kirchhoff Helmholtz积分方法计算远震转换波

Kirchhoff-Helmholtz积分方法推广到远震转换波的合成地震图的计算,其优点是,能够计算复杂界面的地震波。通过与反射率法及动力学射线追踪的对比,表明KH积分方法能很好地模拟远震转换波震相,且精度较高。KH积分方法能够计算任意复杂界面的地震波,是一种研究地壳上地幔结构的有效方法。     

Modeling fluvial response to in‐stream woody vegetation: implications for stream corridor restoration

River restoration and bank stabilization programs often use vegetation for improving stream corridor habitat, aesthetic and function. Yet no study has examined the use of managed vegetation plantings to transform a straight, degraded stream corridor into an ecologically functional meandering channel. Experimental data collected using a distorted Froude‐scaled flume analysis show that channel expansion and widening, thalweg meandering and riffle and pool development are possible using discrete plantings of rigid, emergent vegetation, and the magnitudes of these adjustments depend on the shape of the vegetation zone and the density of the vegetation. These experimental results were verified and validated using a recently developed numerical model, and model output was then used to discuss mechanistically how rivers respond to the introduction of in‐stream woody vegetation. Finally, a hybrid method of meander design is proposed herein where managed vegetation plantings are used to trigger or force the desired morphologic response, transforming a straight, degraded reach into a more functional meandering corridor. It is envisioned that such numerical models could become the primary tool for designing future stream restoration programs involving vegetation and assessing the long‐term stability of such activities. Copyright © 2007 John Wiley & Sons, Ltd.     

钢筋混凝土柱考虑损伤累积的反复荷载-位移关系分析

为能在反复荷载作用下钢筋混凝土柱的荷载-位移关系分析中考虑柱低周疲劳性能,提出了一损伤模型,对柱中纵向受力钢筋和混凝土的损伤状态作评估与记录。将这一记录材料性能信息的损伤指标带入材料各自的恢复力模型以考虑产生损伤后材料的强度和刚度退化。基于多弹簧模型对不同变幅加载路径下及等幅低周疲劳加载下钢筋混凝土柱的空间反应进行了数值计算模拟。与已有试验结果比较表明,所提材料层次上的损伤累积模型以及考虑损伤累积效应的柱构件空间荷载-位移关系分析方法具有一定的精度,为钢筋混凝土柱的抗震性能分析提供了一个辅助工具。     

Shear-wave splitting in the crust beneath the southeast Capital area of North China

This study focuses on the southeast Capital area of North China (38.5–39.85° N, 115.5–118.5° E). Shear-wave splitting parameters at 20 seismic stations are obtained by a systematic analysis method applied to data recorded by the Capital Area Seismograph Network (CASN) between the years 2002 and 2005. Although some differences in the results are observed, the average fast-wave polarization is N88.2° W ± 40.7° and the average normalized slow wave time delay is 3.55 ± 2.93 ms/km. The average polarization is consistent with the regional maximum horizontal compressive stress and also with the maximum principal strain derived from global positioning system measurements in North China. In spite of the uneven distribution of faults around the array stations that likely introduce some amount of scatter in the shear-wave splitting measurements, site-dependent polarizations of fast shear wave are clearly observed: in the northern half of the study area, the polarizations at CASN stations show E–W direction, whereas in the southern half the polarizations exhibit a variety of possible azimuths, thus suggesting dissimilar stress field and tectonic frame in both areas. Comparing the splitting results with those previously obtained in the northwest part of the region, we find a difference in polarization of about 20° between the southeast and northwest parts of the Capital area; also, in the southeast Capital area the average time delay is smaller than in the northwest Capital area, thus making clear that the magnitude of crustal seismic anisotropy is not the same in the two zones. Being the shear-wave splitting polarizations in the southeast Capital area, which lies on the basin, clearly different from the observed polarizations in the northwest Capital area, where uplifts and basin converge, it is quite evident that the shear-wave splitting results are consequence of the tectonics and stress field affecting the two regions.     

松辽盆地地热场

本文实测了65口井的地热数据,从中取得17个大地热流值,松辽盆地地热场具有中部高边部低,并呈环状分布,该区地热具有高特征的地质发展历史。分区计算盆地的沉积岩层、花岗岩质层和玄武岩质层各底部的温度和热流值,也都具有中部高边部低的变化趋势。分析了盆地地热场受影响的状况和地热高的主要原因。还分析了盆地地热场与构造活动性、地震活动性、重磁力场、岩石圈厚度的关系,以及与石油生成、运移和富集的关系。     

高级汉字地震位图绘制软件（SACWSBP）

文中主要介绍位图文件的生成方法及其用该法编制的高级汉字地震位图绘制软件（ＳＡＣＷＳＢＰ）的功能及可能应用。该软件可绘制正式使用的地震图。并着重讨论了了地震位图文件中心；线等基本图形函数的实现，地震图形软件的编制，图形显示，文字标注，汉字输入、与现有中文系统的接口、打印输出，高级汉字地震位绘制条件的功能，特点及其应用情况等，是获得高级精美的地震图形的一种途径，具有较强的实用价值。     

利用地震层析成象技术确定横向非均匀介质中的速度分布和界面位置

本文提出一种横向非均匀介质中的地震层析成象方法，由地震走时资料确定介质的速度分布和界面位置。计算中采用了参数分离、变阻尼、奇异值分解等技术，方程的解较稳定，且可得到解的分办。除反射波外，该方法还可同时利用分析波的资料。因此，适宜于折射及宽角度反射地震测深剖面的资料处理。数字试验结果表明，在模型内部，该方法能得到可靠的反演结果。在边界附近效果较差，受初始值影响较大。