聚合物驱提高采收率发展现状与趋势

聚合物驱作为提高采收率技术是最先发展起来的，本文综述了聚合物驱在目前油田开发中的应用，并对现行的聚合物驱的驱油机理进行了探讨，对以后发展进行了展望。     

杜229块蒸汽驱扩大试验参数优化设计

鉴于杜229块蒸汽驱先导试验较好的开发效果,进行蒸汽驱的扩大试验,为该块规模汽驱作准备。方案设计中在分析先导试验效果的基础上,利用数值模拟方法优化扩大试验的主要注采参数,最大限度地提高蒸汽驱的开发效果和经济效益。     

聚合物驱提高采收率研究

聚合物驱是一种比较有效的提高原油采收率的三次采油方法。综述了聚合物驱技术在国内外的应用和研究进展,分析了聚合物驱的驱油机理。介绍了常见的聚合物驱并提出了发展聚合物驱急需解决的问题。     

Analysis of flooding as a stochastic process in polymer electrolyte membrane (PEM) fuel cells by impedance techniques

Impedance measurements were conducted to gain insight into flooding of a single polymer electrolyte membrane (PEM) fuel cell. The stochastic character of the formation of water droplets and subsequent removal by gas flow is demonstrated to increase the standard deviation of impedance measurements, yielding a sensitive manner to detect onset of flooding. The increase in stochastic noise associated with flooding was more apparent at low frequencies, due to the closer match to the characteristic frequency associated with the growth and removal of water droplets. The onset of flooding was sensitive to the design of the gas diffusion layer.     

Counter-current gas-liquid flow and incipient flooding in inclined small diameter tubes

Free flowing liquid layer characteristics, counter-current gas-liquid two-phase flow and incipient flooding were studied in small diameter inclined tubes (7 and 9 mm). Experiments were carried out at various inclination angles from the horizontal (30°, 45°, 60° and 75°), while several liquids covering a wide range of physical properties were employed. Fast video recordings and conductivity probes were used for liquid layer thickness measurements, from which mean layer thickness and its statistical quantities were calculated. The wall shear stress at the tube bottom was also measured using an electrodiffusion technique.The new experimental data confirm previous interpretation that in almost all cases the dominant flooding mechanism is wave growth and upward dragging by the gas phase. Consequently, incipient flooding is strongly affected by the liquid layer characteristics, which in turn are influenced by the liquid properties. New correlations based on dimensionless groups for the prediction of flooding in inclined small diameter tubes are proposed.     

Compiling network traffic into rules using soft computing methods for the detection of flooding attacks

The ability to dynamically collect and analyze network traffic and to accurately report the current network status is critical in the face of large-scale intrusions, and enables networks to continually function despite of traffic fluctuations. The paper presents a network traffic model that represents a specific network pattern and a methodology that compiles the network traffic into a set of rules using soft computing methods. This methodology based upon the network traffic model can be used to detect large-scale flooding attacks, for example, a distributed denial-of-service (DDoS) attack. We report experimental results that demonstrate the distinctive and predictive patterns of flooding attacks in simulated network settings, and show the potential of soft computing methods for the successful detection of large-scale flooding attacks.     

石油磺酸盐在多孔介质中的色谱效应

本文研究了石油磺酸盐KPS－2在砂管岩心中的色谱效应及其影响因素。流动实验结果表明单、双磺酸盐在岩心砂上的吸附有明显的差别,是导致KPS－2的色谱效应的主要因素。在复合驱体系中加入1％碱剂碳酸钠可以大大地降低石油磺酸的吸附量和色谱分离程度;在稀表面活性剂体系中,聚合物与表面活性剂的不兼容性表现为水解聚丙烯酰胺的加入使KPS－2的色谱分离增加,在动态条件下石油磺酸盐进入油相中的量较小。     

无线传感器网络最优搜索泛洪协议研究

泛洪是无线传感器网络中一种基本的方法,像拓扑形成、路由建立、目标探测或者数据查询等经常使用泛洪策略来实现。在泛洪策略的研究上,以前的研究大多关注于如何产生最优的广播树,同时假定节点之间的通讯是可靠的。然而,在实际的无线传感器网络环境中,这一目标并不是最有效的,而其假设更是不成立的。将最优搜索理论与分簇方法相结合,提出一种高效率的泛洪协议——最优搜索泛洪协议(OSFP),应用于无线传感器网络的目标探测。该泛洪协议既可应用于可靠的数据传输网络,也可应用于不可靠的数据传输网络。仿真结果表明,与其他泛洪协议相比,OSFP可以最大化发现目标的概率而不增加其搜索代价。     

以网络性能为核心的移动自组网Flooding攻击防御技术

移动自组网(Mobile Ad Hoc Networks,MANETs)所面临的Flooding攻击是一种严重DOS攻击行为。然而,现有的针对Flooding攻击的防范技术因不能较好地适应MANETs特性(如有限资源、动态拓扑等)而难以在MANETs网络性能和网络安全之间保持平衡。通过分析移动自组网的时空动态性、网络性能评估与Flooding安全威胁之间的内在关系,提出了一种基于性能评估的Flooding攻击防御技术。通过构建可量化的MANETs安全威胁、防御收益与代价的评估指标体系,实现了基于网络安全和性能平衡的防御及其性能优化方法。仿真实验结果表明,所提出的防御技术可有效地弥补现有移动自组网安全技术存在的一些缺陷,因而能够 满足移动自组网特性且适合于实际应用。     

A visualization study on relationship between water-droplet behavior and cell voltage appeared in straight, parallel and serpentine channel pattern cells

It is a critical issue to understand the relationship between water-droplet behavior and cell voltage for the establishment of PEFC water management. We fabricated three cells, whose channel pattern is different: straight one channel, parallel three channels and serpentine one channel. We operated these different channel-pattern cells and visualized water droplets in cathode channel, with systematically changing operation condition to quantitatively compare the performance and water droplet behavior between the cells. Successive process of water behavior, named as flooding, plugging and flushing, emerged in every channel-pattern cell. However, the each channel pattern cell also has inherent water behavior, showing particular cell voltage variation. Within our experimental condition, the serpentine one channel cell showed a superior tolerance to flooding and the highest performance among the three cells.