地震波非线性反演方法研究综述

地震波非线性反演方法研究跟正演模拟方法研究一样,是地球物理学中一个非常重要的研究领域,其进展对人们正确认识和了解地球内部的细节及物性具有重大意义,对地球动力学的研究也具有不可忽视的推动作用。对地震波非线性反演问题理论研究的进展作了评述;在简单回顾非线性反演方法发展历史的基础上,总结了近年来常见的非线性反演方法研究的最新进展情况,对非线性反演中存在的各种问题进行了比较和评述,同时指出了目前非线性反演方法存在的问题,并对今后发展的方向作了简要展望。     

多孔介质中泡沫的迁移特性和影响因素研究

通过设计一系列模拟柱实验探讨了泡沫在非饱和多孔介质中的运移特征以及泡沫质量、泡沫注入速率、介质渗透率对泡沫注入压力的影响.研究表明:泡沫气体锋面、泡沫液体锋面与泡沫锋面在多孔介质中是分离迁移的,且迁移速度大小关系为泡沫气体锋面>泡沫液体锋面>泡沫锋面;泡沫锋面相对于泡沫气体锋面的延迟系数为2.0.在泡沫运移过程中,模拟柱中压力的产生主要发生并均匀分布在泡沫覆盖区域中,固定点处压力随时间呈直线增加趋势;泡沫在1~1.2mm介质中的有效粘度为85.49mPa·s,是水在介质中运移有效粘度的84.64倍(水的有效粘度为1.01mPa·s).由此可知,泡沫注入模拟柱时需要较大的压力,主要是由于泡沫的有效粘性较大引起的.介质渗透率对泡沫注入压力的影响主要取决于泡沫注入速率;当单位面积泡沫注入速率相同时,泡沫注入压力随介质渗透率增大而降低. 当泡沫质量为91.4%时,当泡沫注入速率由2.1mL/min升高至3.2mL/min与4.4mL/min时,压力梯度由26.95psi/m升高至30.74与46.40psi/m,而当泡沫注入速率为3.2mL/min时,当泡沫质量由93.5%降低至91.4%与88.2%时,压力梯度由30.16psi/m升高至30.74与34.57psi/m,由此可知,泡沫质量与泡沫注入速率均对泡沫注入速率产生影响,然而泡沫注入速率的影响大于泡沫质量对注入压力的影响.     

以PTFE为基布的混织滤料过滤性能及其在燃煤电厂的应用

滤料是袋式除尘器和电袋复合除尘器的核心,通过对目前常用的两种PTFE混织滤料材质结构、加工工艺及适用条件进行的对比分析,并列举了其在燃煤电厂中的应用效果,阐明了混织滤料的优良过滤性能,适用于烟气温度高、粉尘排放要求较高、工况变化大的燃煤电厂。     

粒状滤料过滤技术发展与应用的探讨

粒状滤料过滤技术广泛用于废水的深度处理.过滤技术使用后,快滤池技术发展迅速.随着多种滤料的开发,深层过滤技术得到发展,直接过滤工艺应运而生.反冲洗是快滤池的一项关键技术,气水联合反冲洗对滤料过滤能力的再生效果优于单水反冲洗.滤料过滤存在跑料、料层板结等问题,在工程实践中逐步得到改进.     

NUMERICAL AND ANALYTICAL SOLUTIONS OF DISPERSION IN A FINITE,ADSORBING POROUS MEDIUM1

ABSTRACT Numerical and analytical solutions are developed for the distribution of a contaminant within an adsorbing porous medium in a unidirectional flow field subject to a step function for input concentration. The medium is considered to be homogeneous, isotropic, and areally finite. As a by-product, solutions are also obtained for the case of a non-absorbing porous medium. An example that demonstrates the applicability of the solutions is presented.     

DEVELOPMENT AND APPLICATION OF A MODFLOW PREPROCESSOR USING PERCOLATION THEORY FOR FRACTURED MEDIA1

ABSTRACT: The discrete heterogeneity of fracture distribution and hydraulic discontinuity are the primary difficulties in the modeling of flow in fractured media. The equivalent porous medium (EPM) approach, however, which has been frequently applied to simulate flow in fractured media due to its ease of use, ignores this. This practice results in some severe limitations such as hydraulic head averaging and an inability to handle preferred fluid pathways. The PMF package (a Preprocessor to MODFLOW for Fractured media) was developed employing percolation theory to address these limitations and to utilize the simplicity of the EPM approach at the same time. This preprocessor was applied to a fractured rock aquifer around Cranberry Lake in northern New Jersey. The calibration using hydraulic head observations, validation using water balance, and evaluation using residuals show that the model generated by the PMF package can provide a superior simulation of ground water flow to the EPM approach.     

局域网内ARP协议攻击及解决办法

地址解析协议(ARP,Address Resolution Protocol)是用于关联某个3层(网络层)地址(如IP地址)和某个两层(数据链路层)地址(MAC地址)。由于ARP协议的自身的缺陷,使得ARP协议在使用的过程中存在着盗用IP地址和ARP欺骗等严重的安全问题。笔者在对ARP协议简要介绍的基础上,主要分析了利用ARP协议漏洞进行网络攻击的原理和攻击的常见方式,并提出相关的ARP攻击的解决办法。     

悬浮填料滤池固液分离新技术的中试试验研究

本文提出了采用悬浮填料滤池对活性污泥混合液进行固液分离的新技术。该技术所采用的悬浮填料滤池可直接设置在生化反应池末端,取消原工艺中的二沉池。中试试验对悬浮填料滤池的固液分离效果,滤池的运行周期及冲洗方法进行了研究。试验证明,悬浮填料滤池运行稳定,在进水表面负荷高达2.0~3.0 m3/m2.h的情况下出水SS达到城镇污水处理厂污染物二级排放标准(GB18918-2002),工作周期可达到5天以上。悬浮填料滤池可采用曝气方法进行冲洗,操作管理简单,冲洗效果良好,便于实现自动化运行。     

Chemical Warfare Materiel: Unique Regulatory Issues

In those states that have not included CWM as hazardous materials in their RCRA programs, the RCRA requirements for management of hazardous waste would not strictly apply to any of the CWM. The Army has historically implemented procedures requiring that chemical warfare agents be managed as RCRA hazardous waste regardless of the concentration, physical form, or configuration of the agent. Such application of strict hazardous waste requirements to management of potentially nonhazardous CWM can result in remedial costs well out of proportion to potential human health and environmental benefits. Recent development of chronic toxicity values for the CWM has opened the door for development of cleanup and waste management standards for waste streams or media containing small residual amounts of CWM. Implementation of this health-based approach to management of CWM remediation wastes may, in part, help to reduce potentially unnecessary hazardous waste management costs for the nonhazardous CWM.     

Evaluation of the effectiveness of horizontal subsurface flow constructed wetlands for different media

Two media bed (gravel and Filtralite NR) were tested in a mesocosm to evaluate the removal of organic matter (as chemical oxygen demand (COD)),ammonia (NH4-N),nitrite,nitrate and solid matter (as total suspended solids (TSS)) for a synthetic wastewater (acetate-based) and a domestic wastewater.The use of Filtralite allowed average removal rates (6–16.8 g COD/(m2·day),0.8–1.1 g NH4-N/(m2·day) and 3.1 g TSS/(m2·day)) and removal effciencies (65%–93%,57%–85% and 78% for COD,NH4-N and TSS,respectively),higher than that observed in the experiments with gravel.The applied loads of COD,ammonia,nitrate and TSS seem to influence the respective removal rates but only for the treatment of domestic wastewater with higher correlation coefficients for Filtralite.Regardless the type of media bed and the type of wastewater,nitrate was completely removed for nitrogen loading rates up to 1.3 g NO3-N/(m2·day).There was no evidence of the influence of nitrate loads on the removal of organic matter.