双决策变量法在水电站优化调度中的应用

对调度模型以隐随机优化为基本途径求解，采用两个决策变量，用传统最小二乘法及水能计算方法，寻求合理、有效的水电站优化调度规则。通过实例计算表明：双决策调度实际应用所得的经济效益明显优于常规调度。     

以水资源的可持续利用支持中国社会经济的可持续发展

水资源可持续利用的目的在于支持经济社会的可持续发展。经济、社会的发展是需水部门，如何由水工程或其他措施供水是供水部门，二者必须多次反馈、协调才能作出一个统一的决策。西方先阐述人类与发展，可持续发展的要求和水资源的可持续利用3个问题，然后引用土耳其GAP地区的水与发展为例，并以长江流域为对象探讨这一主题。     

卸压瓦斯抽采技术实践应用研究

矿井瓦斯是引起煤矿安全事故的重要原因,卸压瓦斯抽采技术是实现煤与瓦斯共采的重要手段.介绍了卸压瓦斯抽采技术的理论基础,介绍了四种卸压瓦斯抽采方法,实践证明工作面卸压瓦斯抽采可实现良好的社会与经济效益.     

United friction resistance in open channel flows

It is now over half a century since Keulegan conducted his open channel flow experiments.Over the past decades,many empirical formulae were proposed based on his results,however,there is still not a combined expression to describe the effects of friction over all hydraulic regions in open channel flows.Therefore,in this letter,based on the analysis of the implicit model and the logarithmic matching method,the results of Keulegan(for authentic experiment data are no longer available,here we adopt the analytical solutions given by Dou)are rescaled into one monotone curve by combining the Reynolds number and the relative roughness of the river bed.A united expression that could cover the entire turbulence regions and be validated with Dou’s analytical solutions is suggested to estimate the friction factor throughout the turbulent region in open channel flows,with higher accuracy than that of the previous formulas.     

水资源可持续利用与社会发展

本文就目前中国社会转型大背景下，针对社会发展大系统中的自然资源与环境要素，围绕水资源在社会经济发展中的作用，就水资源在社会发展系统中的影响作用进行分析与论证。     

STUDY AND APPLICATION OF STEADY FLOW AND UNSTEADY FLOW MATHEMATICAL MODEL FOR CHANNEL NETWORKS

Based on the Preissmann implicit scheme for the one-dimensional Saint-Venant equation, the mathematical model for one-dimensional river networks and canal networks was developed and the key issues on the model were expatiated particularly in this article. This model applies the method of three-steps solution for channel-junction-channel to simulate the river networks, and the Gauss elimination method was used to calculate the sparse matrix. This model was applied to simulate the tree-type irrigation canal networks, complex looped channel networks and the Lower Columbia Slough networks. The results of water level and discharge agree with the data from the Adlul and field data. The model is proved to be robust for simulating unsteady flows in river networks with various degrees of complex structure. The calculated results show that this model is useful for engineering applications in complicated river networks. Future research was recommended to focus on setting up ecological numerical model of water quality in river networks and canal networks.     

不同隐格式法在工程实例中的应用

采用preissmann隐格式法和特征隐格式法对同一工程输水运行时的明满流现象进行了数值模拟,具体介绍了两种数学模型的不同之处以及边界处理方法,并对计算结果进行分析和比较,提出在计算明满流时特征隐格式法较preissmann隐格式法适用性强。     

Do social support interventions ("buddy systems") aid smoking cessation? A review

OBJECTIVE: To provide an overview of the role of social support in smoking cessation and to critically review evidence regarding the use of "buddy systems" (where smokers are specifically provided with someone to support them) to aid smoking cessation. DATA SOURCES: Studies were located by searching Medline and Psyclit using the key words "smoking", "smoking cessation", "social support", and "buddy". Additional studies were identified through reference lists. Only studies reported in English and published since 1980 were included. STUDY SELECTION: Studies were selected on four criteria: publication in a peer reviewed journal; randomised controlled trial using smokers who wanted to stop; the use of a social support intervention, including a "buddy"; dependent variable of smoking abstinence. Most research in this area does not use a randomised design so only a small proportion of the originally identified studies were included. DATA SYNTHESIS: In view of the diverse nature of the studies, a meta-analysis was not attempted. Ten studies were identified: nine were clinic based smoking trials, eight used a group format, and nine used buddies from among smokers' existing relationships. Support training varied from role play and rehearsal to a simple instruction to call each other regularly. Intervention and follow up periods varied between studies. Two studies showed a significant benefit of the intervention in the short term. CONCLUSIONS: Research methodology in many cases was poor. The evidence would suggest that in the context of a smokers clinic the use of buddies may be of some benefit. There is a lack of evidence regarding the efficacy of the use of buddies in community interventions. This is an important area for future research.     

有杆抽油系统预测模型的隐式差分法

现有的求解有杆抽油系统预测模型的方法都存在一定的局限性 ,为此 ,把抽油泵处的边界条件处理成一维方程 ,与求解波动方程第一类初边值问题的隐式差分方程组合并 ,提出了求解预测模型的隐式差分法。隐式差分法是无条件稳定的 ,它可以根据精度要求合理地选择步长 ,从而显著节省计算时间。实例计算表明 ,隐式差分法与显示差分法计算结果非常接近 ,其中隐式差分法能计算出抽油杆在任一瞬时与任一截面的位移和载荷 ,适合于各种工况下的抽油井预测。     

管理型工程项目管理之路

管理型工程项目是现在施工企业普遍采用的一种施工模式,以较少的人员投入,完成较多的产值,实现较多的利润,达到增加企业积累、扩大企业发展的目的。通过采用切实可行的管理办法,在以我为主、有效驾驭的前提下,吸引、团结、聚集、利用一大批履约能力强,能够共担风险的社会资源力量,为企业走好管理型项目发展道路提供充足的资源保障。