考虑毛管数和非达西效应的凝析气液两相流入动态

近期的大量理论和实验研究发现,高速流动导致的毛管数和非达西效应对近井油气相对渗透率有显著影响,而目前仅仅考虑非达西效应无法准确描述油气真实渗流状态。如何准确理解并考虑这两种效应的影响对于凝析气藏渗流动态分析以及生产动态预测有很重要的意义。本文建立了油气两相渗流的定解问题,得到了拟稳态形式的流入动态方程。在三区渗流机理上,首次综合考虑了毛管数和非达西效应对相对渗透率的影响。实例分析揭示了高速流动下油气相对渗透率变化及油气分布状态新特征。对不同流入动态模型的对比分析表明,本文方法较之现有方法更有助于正确预测生产动态,评估气井产能。     

News media coverage of smoking and health is associated with changes in population rates of smoking cessation but not initiation

OBJECTIVE: To determine whether changes in news media coverage of smoking and health issues are associated with changes in smoking behaviour in the USA. DESIGN AND MAIN OUTCOME MEASURES: Issue importance in the US news media is assessed by the number of articles published annually in major magazines indexed in The Reader's Guide to Periodical Literature. Annual incidence rates for cessation and initiation in the USA were computed from the large, representative National Health Interview Surveys (1965-1992). Patterns in cessation incidence were considered for ages 20-34 years and 35-50 years. Initiation incidence was examined for adolescents (14-17 years) and young adults (18-21 years) of both sexes. RESULTS: From 1950 to the early 1980s, the annual incidence of cessation in the USA mirrored the pattern of news media coverage of smoking and health, particularly for middle aged smokers. Cessation rates in younger adults increased considerably when second hand smoke concerns started to increase in the US population. Incidence of initiation in young adults did not start to decline until the beginning of the public health campaign against smoking in the 1960s. Among adolescents, incidence rates did not start to decline until the 1970s, after the broadcast ban on cigarette advertising. CONCLUSIONS: The level of coverage of smoking and health in the news media may play an important role in determining the rate of population smoking cessation, but not initiation. In countries where cessation has lagged, advocates should work to increase the newsworthiness of smoking and health issues.     

P2P视频在人才招聘网站上的应用

简要描述了传统人才招聘网站的方式；从招聘的流程、环节、方式等方面，从现实的情况提出了“P2P视频优化的即时沟通方式”：重点介绍P2P即时通讯的视频方式对网站优化所起到的作用和优点；通过对P2P视频在网站上的优点的分析，说明分P2P的视频应用是完全可行的．有助于企业、人才、网站三方面优化和提高效率。     

ASF流媒体切割技术的研究与实现

ASF文件作为当前主要的流媒体格式之一，给人们的生活带来极大的方便。但同时受到广告泛滥、内容模糊，不能分离精彩片段的严重制约，必须开发一种对其进行编辑的软件，既节省时间，又可以反复观看经典内容。并且通过使用WMF SDK提供的生成器、读取器、编辑器可以忽略ASF文件底层的实现细节，提高开发效率。针对ASF文件切割中存在的问题，对切割精度、绕开生成器的压缩编码过程、属性编辑等方面进行了研究，并实现了对ASF文件的切割。     

Additive Schwarz with aggregation-based coarsening for elliptic problems with highly variable coefficients

Summary We develop a new coefficient-explicit theory for two-level overlapping domain decomposition preconditioners with non-standard coarse spaces in iterative solvers for finite element discretisations of second-order elliptic problems. We apply the theory to the case of smoothed aggregation coarse spaces introduced by Vanek, Mandel and Brezina in the context of algebraic multigrid (AMG) and are particularly interested in the situation where the diffusion coefficient (or the permeability) α is highly variable throughout the domain. Our motivating example is Monte Carlo simulation for flow in rock with permeability modelled by log–normal random fields. By using the concept of strong connections (suitably adapted from the AMG context) we design a two-level additive Schwarz preconditioner that is robust to strong variations in α as well as to mesh refinement. We give upper bounds on the condition number of the preconditioned system which do not depend on the size of the subdomains and make explicit the interplay between the coefficient function and the coarse space basis functions. In particular, we are able to show that the condition number can be bounded independent of the ratio of the two values of α in a binary medium even when the discontinuities in the coefficient function are not resolved by the coarse mesh. Our numerical results show that the bounds with respect to the mesh parameters are sharp and that the method is indeed robust to strong variations in α. We compare the method to other preconditioners and to a sparse direct solver.      

计算机辅助教学与学生学习关系之探悉

20世纪90年代，计算机多媒体技术的问世，为新时期的教学提供了新的内容和手段。随着多媒体技术的日益成熟和普及，多媒体技术在教学中应用日益普遍，计算机辅助教学已成为教学过程中必不可少的手段。     

P2P视频在人才招聘网站上的应用

简要描述了传统人才招聘网站的方式;从招聘的流程、环节、方式等方面,从现实的情况提出了“P2P视频优化的即时沟通方式”;重点介绍P2P即时通讯的视频方式对网站优化所起到的作用和优点;通过对P2P视频在网站上的优点的分析,说明分P2P的视频应用是完全可行的,有助于企业、人才、网站三方面优化和提高效率。     

RTSP流媒体代理IPv4/IPv6组播互通的研究

基于RTSP协议的流媒体应用发展迅速,在Internet上传输流媒体的相关技术成为热点。在网络和网络应用从IPv4向IPv6过渡的过程中,新构建的基于IPv6的实时RTSP流媒体组播应用要求能够与原有基于IPv4的实时RTSP流媒体组播应用互通。分析了当前主流的流式多媒体信息的发布平台Microsoft的Windows MediaService以及RealNetworks的Helix Universal Server对组播的实现方式,并研究对支持IPv4/IPv6网络间互访的RTSP流媒体应用代理进行一些扩展来实现IPv4/IPv6 RTSP流媒体组播应用互通。     

基于自定义流媒体格式的远程教学系统设计

构建了一种以自定义流媒体格式进行网上传输的远程教学系统框架。自定义媒体格式遵循RIFF(Resource Interchange File Format)规范,将多路音视频存储在一个文件中。该系统具有成本低,存储简单,多媒体课件同步性高,可扩展性强的特点,可用于远程教学,视频点播等多个领域。     

水介质中制备铝粉颜料的研究

以蒸馏水替代有机溶剂制备环保型铝粉颜料,通过优化组合获取一种优良的复合缓蚀剂,以抑制铝粉在球磨过程中与水发生反应;通过优化转速、球料比及球磨时间等工艺参数,获得制备铝粉颜料的最佳条件:转速为300r/min,球料比为25∶1,球磨时间为6h.