EXPERIMENTAL AND NUMERICAL STUDY FOR HYDRODYNAMIC CHARACTERISTICS OF AN OSCILLATING HYDROFOIL

The present article reports the experimental Particle Image Velocimetry （PIV） investigation and the corresponding numerical simulation results about the water flow over the oscillating hydrofoil and its unsteady dynamic characters. The experimental study focuses on the effect of mean angles of attack. The comparison between the PIV results and numerical prediction about the flow field using Fluent well demonstrates the capability of CFD on the simulation of the water flow around the pitching hydrofoil. The numerical results indicate that the forced oscillating frequencies have evident effects on the flow separation and vortex shedding. The simulations about the hydrodynamic drag and lift coefficients were also performed.     

The performance of newly privatized firms in selected MENA countries: The role of ownership structure, governance and liberalization policies

The paper analyzes 95 newly privatized firms (NPFs) in four Middle Eastern and North African countries (Egypt, Morocco, Tunisia, and Turkey). We find that these firms experienced significant increases in profitability and operating efficiency, and significant declines in employment and leverage. We also document strong performance improvements for firms that did remain state-owned, that were not sold to foreigners, and that came from Egypt. Job losses are higher in Egypt and in firms where the state is no longer in control. Also, the results indicate that revenue firms and NPFs in Morocco display significantly less leverage than control firms and those from other countries. We find that profitability changes are negatively related to state control and positively related to foreign ownership. Trade openness, change in real GDP over the privatization window, index of investor protection, and foreign ownership are important determinants of the changes in sales efficiency and output. These findings suggest that NPFs become more productive in environments where property rights are better protected and enforced and that foreign investors influence firms' productivity through their monitoring role.     

考虑风险因素的第三方物流企业合作伙伴选择研究

在考虑风险因素的前提下研究了第三方物流企业合作伙伴的选择问题。首先提出了考虑风险因素的合作伙伴选择指标体系,其次采用层次分析法和模糊TOPSIS法相结合的综合方法对物流企业合作伙伴进行选择,最后通过案例验证了该方法的合理性。     

三维有限元渗流模拟计算在水库安全评价中的应用研究

本文先介绍了有限元在土木工程中的发展过程以及渗流研究现状,然后以云南省允楞水库为例,对水库安全评价中的渗流分析进行三维有限元渗流模拟计算,计算结果跟实测值比较,说明三维有限元渗流模拟在渗流分析中的可行性。     

Development and introduction of new designs for gas-dust flow mixing distribution systems at thermal power plants

The successful introduction and setup of new designs for dust separators in Russian and foreign 200–800 MW coal-fired power production units is described. Results from mathematical and physical modelling of these designs, as well as data on their operation in test stands, are presented. Recommendations are given for the most suitable equipment and configurations of new dust distribution systems in dust preparation systems. Translated from élektricheskie Stantsii, No. 7, July 2008, pp. 10–23.     

3ds max 建模在织物组织结构教学中的应用

本文介绍了利用3ds max建模在织物组织结构教学中的应用特点、优势和对教师的要求,对应该注意的问题也作了说明,同时3ds max织物组织立体建模作了概述。3ds max建模在织物组织结构教学中的应用对织物组织教学提供了新的方法和途径,特别是对于初学织物组织的学生来说,更易理解组织图与组织结构之间的关系。     

对企业并购估价中威斯通模型的进一步研究

威斯通模型是企业并购估值贴现现金流模型中具有代表性的研究。首先对超常增长而后无增长的威斯通模型作了一点修正;接着建立了企业在超常增长期采取不同投资策略时的估价模型;最后分析了新建模型与原模型的差异,并通过数例对两模型进行了敏感性分析。     

呼和浩特抽水蓄能电站蜗壳回填灌浆施工技术

针对呼和浩特抽水蓄能电站厂房座环、蜗壳阴角部位狭窄、空间小,混凝土浇筑易形成局部空腔的问题,介绍了环向充气式拔管、直埋式注浆钢管多循环平衡注浆技术,并介绍了施工的技术要求、施工程序和方法,提出了在灌浆过程中对蜗壳位移进行监测及应急处理措施。经质量检查,灌浆效果良好,解决了蜗壳座环底部回填灌浆难题。     

螺旋式调压井运输通道下压力钢管安装工法

大湾水电站调压井设计方案为底坡i=13%,断面6m×6m城门洞形螺旋式,洞身长310m。为合理节约投资、节省工期,调压井底板混凝土浇筑后,即作为压力钢管安装运输通道使用。安装单位根据洞身变径、螺旋式特点,巧妙地运用卸车天锚、导向地锚配合卷扬机、滑车系统,顺利完成安装任务,解决了该工程压力钢管运输难题。其经验可为其他类似工程参考。     

The use of non-persistent herbicides,glyphosate, and 2,4-D amine,to control riparian stands of Japanese knotweed (reynoutria japonica houtt.)

The non-persistent herbicides glyphosate and 2,4-D amine were applied to riparian stands of R. japonica on the banks of the River Cynon, South Wales at doses of 2154 g and 2790 g active ingredient (a.i.) ha^?1 respectively. Glyphosate being tested with one or two applications per season, 2,4-D amine with two only. Two weeks after spraying, the biomass and leaf area ratio of shoots in all treated plots was depressed but was significantly (P < 0–01) lower in the 2,4-D amine plots. Ten weeks after treatment shoots had begun to recover but the biomass was still < 40 per cent of the control areas. Rapid (six weeks after treatment) recovery of Leaf Area Ratio was also observed. Second applications of glyphosate and 2,4-D amine to the respective plots resulted in shoot death after four weeks. Management recommendations are made for the control of R. japonica on riverbanks based on the results presented.