基于表面反应和扩散迁移控制的灰岩单裂隙渗流—溶解模型及其数值模拟

针对碳酸盐类可溶岩地区水电站坝址流场、化学场以及固相介质属性等随时间发生改变,从而对工程安全运行造成不利影响等问题,研究了灰岩地区地下水运移过程中各物理场间的相互作用,分析了影响灰岩溶解速率的两个因素,即表面反应控制和扩散迁移控制。在此基础上,建立了单裂隙中的渗流—溶解耦合模型,并进行数值求解。模拟结果表明,在垂直裂隙延伸方向,其溶蚀锋面为非齐整平面,而是呈似“虫洞”状非均一变化,而沿裂隙延伸方向即自上游侧向下游方向溶蚀程度逐渐减轻;而通过裂隙的流量呈现随时间逐渐增大的趋势,但变幅不大;根据流量求得的等效水力隙宽,其增幅和增长速率均小于实际平均隙宽;同时,化学场中Ca2+浓度的分布与裂隙开度变化具有相似性,不同时刻下上游侧反应速率R均大于下游侧。就反应机制而言,在初期均受表面反应控制,而随反应进行,位于上游补给区部位转为受扩散迁移控制,但在下游位置仍受表面反应控制。     

高温预析出对Al-Zn-Mg-Cu铝合金显微组织、强度和应力腐蚀抗力的影响

通过改变固溶条件 ,对Al Zn Mg Cu高强铝合金采用先高温后低温的两步固溶处理 (高温预析出 )来改善晶内和晶界的析出状态 ,研究了高温预析出对Al Zn Mg Cu铝合金的金相组织、强度和应力腐蚀性能的影响。结果表明 ,4 6 5℃高温预析出在保持较高强度和塑性的同时 ,可以改善合金的抗应力腐蚀性能     

Nitrogen removal using recycled polystyrene bottles as biofilm media

The performance of an attached growth wastewater treatment process was investigated in an effort to improve nitrogen removal efficiency. Recycled Yakult (lactic acid fermentation drink) bottles made of polystyrene were used as a biofilm media. The use of Yakult bottles as a biofilm media has been attempted by numerous researchers in Japan for the removal of solids and organics. However, these studies focused only on the removal of solids and organics. This study extended their application to the removal of nitrogen for domestic sewage treatment. Yakult media was placed in a reactor with 70% apparent reactor volume in a conventional A/O process. The bottom of the Yakult media was removed, and randomly filled Yakult media were effectively able to reduce the flow in tanks, resulting in an increase in the contact time between pollutants and microorganisms. With higher HRT, the nitrogen removal efficiency was increased by up to 83% with 12 hr of HRT. Nitrification appeared to be the limiting factor of nitrogen removal at an HRT that is less than 12 hr, indicating that the Yakult process requires more retention time to achieve nitrification compared to other biofilm processes. The removal efficiencies of organics and solids were high regardless of the change of operational parameters. This article is based on a presentation in “The 7th Korea-China Workshop On Advanced Materials” organized by the Korea-China Advanced Materials Cooperation Center and the China-Korea Advanced Materials Cooperation Center, held at Ramada Plaza Jeju Hotel, Jeju Island, Korea on August 24–27, 2003.     

真空水冷铜坩埚感应炉模糊控制专家系统的研究

研究真空水冷铜坩埚感应炉中模糊控制专家系统。阐述该炉控制系统复杂性 ,介绍模糊控制专家系统的主要结构和各主要部分的功能和一些算法     

粘土砂旧砂再生效果与其含水量的关系

在影响粘土砂旧砂再生效果的诸多因素中,旧砂中水分含量是最重要的因素。本文就水分含量对再生效果的影响规律、再生效果最佳的水分含量等进行了研究和分析,得出了如下结论:并非含水量越低再生效果就越好,而是存在一个去泥率低谷区;再生效果最佳的适宜水分含量为1～2%。     

焊接企业生产管理系统

通过对焊接企业的分析和总结,以 Oracle 为数据平台,运用面向对象的插件开发技术,设计、开发了焊接企业生产管理系统,以便对企业焊接生产线上所有物质、流程进行更精准的监控、管理,如对焊材、母材的管理等。同时,该系统集成了各种焊材的国家检验标准数据,并支持按企业特性进行修改,为质检人员制定标准提供便捷。     

基于冗余链路的校园网流量管理设计与实现

分析了目前校园网用户体验宽带不宽的主要因素,针对校园网出口冗余链路提出基于时间策略的负载均衡方案,并对校园网骨干架构做出相应调整,经过实际应用测试,保障了用户办公学习网络应用带宽,提高了校园网用户满意度。     

Statistically uniform intra-block refresh algorithm for very low delay video communication

This paper focuses on the mechanism underlying the overall delay of a real-time video communication system from the time of capture at the encoder to the time of display at the decoder. A detailed analysis is presented to illustrate the delay problem. We then describe a statistically uniform intra-block refresh scheme for very low delay video communication. By scattering intra-blocks uniformly into continuous frames, the overall delay is significantly decreased, and object changes in the scene could be presented to the end user instantly. For comparison, the overall delay and the peak signal-to-noise ratio (PSNR) performance are tested. The experiment results show that an average of approximately 0.1 dB PSNR gain on average is obtained relative to random intra-macroblock refresh algorithm in H.264 JM, and the end-to-end delay performance is significantly improved.