Use of electrophoresis for transporting nano-iron in porous media

Research has been conducted to evaluate if electrophoresis could transport surface stabilized nanoscale zero-valent iron (nZVI) through fine grained sand with the intent of remediating a contaminant in situ. The experimental procedure involved determining the transport rates of polymer modified nZVI and hematite in fine grained sands under an applied electrical gradient under different physical and chemical conditions. Results indicated transport of polymer modified nZVI and hematite can be accomplished by electrophoresis, with rates found to be much higher than diffusion alone and comparable to those predicted by electrokinetic theory. This study indicates there is potential for this method to deliver polymer modified nZVI into contaminated zones within fine grained sands for the purpose of remediation.     

江西金山金矿韧性剪切带控矿特征探讨

叙述了江西金山金矿韧性剪切带构造岩分带、蚀变分带及金矿化强度分带“三位一体”的规律性分布特征,分析了金山韧性剪切带控矿特征,指出金山韧性剪切带严格控制矿体的产出,其变形变质作用对金的成矿和富集提供容矿空间和动力条件.     

基于语义匹配和QoS的Web服务混合选择方法

提出了一种Web服务语义匹配方法,在此基础上分析了基于语义匹配和基于QoS(服务质量)的服务选择策略,以及面向独立服务和组合服务的服务选择方法,并给出了结合语义匹配和QoS指标值的Web服务混合选择策略及算法.实例分析结果表明,该混合选择策略能针对不同的服务需求作相应的处理,增加了服务选择的正确性,提高了服务组合效率.     

多源卫星遥感影像时空融合研究的现状及展望

高空间分辨率的地表或者大气环境动态监测需要高时间-空间分辨率的卫星遥感影像作为数据支撑,但由于卫星传感器硬件技术及卫星发射成本等客观因素的限制,使得获取高时空分辨率遥感影像的较为便捷高效、低成本的可行手段就是将分别具有高时间和高空间分辨率的多源遥感影像进行时空融合,从而生成不同研究和应用所需的高时空分辨率卫星影像。现阶段,虽然国内外的学者进行了大量的时空融合算法研究,但是这些研究都局限于特定的数据类型、算法原理、应用目的等客观限制,而且其发展呈现出多样性。本文对现有主流的时空融合算法研究进行了归纳总结,将其分为4种:(1)基于地物组分的时空融合;(2)基于地表空间信息的时空融合;(3)基于地物时相变化的时空融合;(4)组合性的时空融合。同时,本文还对时空融合算法中存在的问题和面临的挑战进行了分析,并对其未来的发展方向进行了前瞻性的展望。     

西藏错龙错晚三叠世粗粒巨斑二长花岗岩锆石U-Pb年龄和地球化学特征

对出露于冈底斯中带偏西部错龙错地区原划为早白垩世的粗粒巨斑二长花岗岩进行了较系统的岩石学、LA-ICP-MS锆石U-Pb定年、地球化学研究。结果表明,该地区粗粒巨斑二长花岗岩的成岩年龄为212.6±2.7Ma,属晚三叠世。岩石为高钾钙碱性-钾玄岩系列,具高SiO_2、K_2O的特征。Al_2O_3含量为13.18%~16.26%,铝饱和指数A/CNK为0.96~1.33(平均值为1.11),为准铝质-过铝质花岗岩。稀土元素总量在182.99×10~(-6)~324.34×10~(-6)之间,轻稀土元素明显富集,重稀土元素相对亏损,δEu值变化于0.38~0.57之间,具明显的负Eu异常。微量元素富集K、Rb、Th和相对亏损Ba、Nb、Sr、P、Ti,具有类似造山后花岗岩的微量元素特征。该类岩石的地球动力学背景应为班公湖-怒江洋壳南向俯冲有关的由挤压向伸展转变的同碰撞向后碰撞的过渡阶段。     

Predicting the tails of breakthrough curves in regional-scale alluvial systems

The late tail of the breakthrough curve (BTC) of a conservative tracer in a regional-scale alluvial system is explored using Monte Carlo simulations. The ensemble numerical BTC, for an instantaneous point source injected into the mobile domain, has a heavy late tail transforming from power law to exponential due to a maximum thickness of clayey material. Haggerty et al.'s (2000) multiple-rate mass transfer (MRMT) method is used to predict the numerical late-time BTCs for solutes in the mobile phase. We use a simple analysis of the thicknesses of fine-grained units noted in boring logs to construct the memory function that describes the slow decline of concentrations at very late time. The good fit between the predictions and the numerical results indicates that the late-time BTC can be approximated by a summation of a small number of exponential functions, and its shape depends primarily on the thicknesses and the associated volume fractions of immobile water in "blocks" of fine-grained material. The prediction of the late-time BTC using the MRMT method relies on an estimate of the average advective residence time, t(ad). The predictions are not sensitive to estimation errors in t(ad), which can be approximated by L/v , where v is the arithmetic mean ground water velocity and L is the transport distance. This is the first example of deriving an analytical MRMT model from measured hydrofacies properties to predict the late-time BTC. The parsimonious model directly and quantitatively relates the observable subsurface heterogeneity to nonlocal transport parameters.     

MBACI sampling of an episodic disturbance: stormwater effects on algal epifauna

Whilst it has been well established that stormwater and associated contaminants negatively impact the quality of recipient waters, the ecological effects of individual stormwater pulses in marine environments are relatively unknown. In this study, the impacts of stormwater outfalls upon water quality and epifaunal invertebrates inhabiting the alga Sargassum linearifolium are assessed through an MBACI sampling program. Water quality and the abundance of mobile algal epifauna were recorded at three control sites and three impact sites every 10-12 weeks during dry weather and opportunistically within 24h of large rain events (>50 ml rainfall in 24h) and again 4d after the rain event. Sampling took place during two periods over two separate years and this included four large rainfall events. Following rainfall, salinity dropped rapidly at impact sites close to stormwater outfalls, whilst turbidity increased. Declines in salinity at control sites were slight and turbidity did not differ to 'before' periods. The abundance of epifaunal gastropods and polychaetes were reduced at impact sites 24h after rain events, but not control sites. The abundance of copepods, amphipods and ostracods, however, were reduced at both control and impact sites for up to 4d following rainfall. Reductions of these taxonomic groups could not be attributed to stormwater outfalls. Whilst short-term impacts of stormwater runoff were identified for some faunal groups, impacts were not identified for the majority. Instead, effects were harbour-wide (i.e. at control and impact sites), probably in response to the physical disturbance of heavy seas associated with large rain events.     

层结流体中具有纬向基本剪切流的Rossby波振幅的mKdV方程

In this paper,modified Korteweg-de Vries (mKdV) equations for the amplitude of solitary Rossby waves in stratified fluids with a zonal shear flow are derived by using a weakly nonlinear method.It is found that the coefficients of mKdV equations depend not only on the β effect and the Visl-Brunt frequency,but also on the basic shear flow.     

1992年加州半德斯地震的前震序列及对地震起始的推断

１９９２年６月２８日加州兰德期地震震前有一个７小时的前震序列，它至少由２８个地震组成，在这次研究中，我们根据附近台站记录的地震波形互相关的高精度定位，对几何条件和时间进程进行了仔细胞调查。在兰德斯地震中，确定出现了这情况，虽然不均匀的尺度很少，以用常规定位技术都无法确定。     

GIS中空间模糊叠加模型的设计

空间叠加模是地理信息系统中重要的空间分析模型。本文在介绍传统的叠加模型的基础上，提出了基于模糊集合论的叠加模型。并介绍了该模型的实现过程及隶属度确定的方法。