Lift distribution based design of two-dimensional sections

A lift distribution based section design method has been proposed. Through Newton-Raphson iterations, the section geometry is efficiently designed to meet the requirements for total lift and lift distribution. The effect of fluid viscosity on total lift is taken into account by coupling Reynolds-averaged Navier-Stokes (RANS) simulation with the potential-flow based design procedure. The present method avoids the difficulty of assigning velocity or pressure distributions on section surfaces. As the loading and thickness distributions are expressed in parametric forms, it is easy to ensure that the designed geometry is continuous and smooth. The effects of lift and thickness distributions on cavitation bucket are numerically investigated. A shift of lift loading towards the aft part of section tends to decrease the margin of back cavitation, while the width of cavitation bucket can be kept almost unchanged. To have a wider cavitation bucket, one can increase the leading edge radius, move properly the location of maximum thickness towards the leading edge, or decrease the curvature at the location of maximum thickness.     

高墩大跨径连续刚构桥双肢墩系梁设置道数与地震响应关系分析

为了研究系梁设置道数对大跨双肢薄壁高墩连续刚构桥自振特性及地震响应的影响,文中以清水江大桥为背景,利用 MIDAS/Civil程序,建立了空间有限元仿真分析模型,分析了系梁的道数对结构自振特性的影响,通过反应谱法讨论了在不同系梁道数下桥梁结构的地震响应规律。     

民企外包产品质量问题的分析与改进

以所驻民营企业为研究对象,就军代表在民营企业外包产品质量监督工作中应发挥的作用进行了分析,并提出了具体对策。     

楼梯升降机在地铁的选用设计

从楼梯升降机的种类、功能和结构，技术参数，驱动和牵引方式，使用操作和通信方式，主要技术要求等方面，介绍了楼梯升降机在地铁车站的选用设计。     

基于Vague集和GIS的铁通运营决策支持系统

铁通运营决策支持系统的应用使铁通公司决策智能化,提高了决策的质量和效率.介绍了系统设计和功能结构,阐述了数据仓库技术、GIS技术在Vague集决策支持系统中的应用.该系统实现了数据库管理,问题分析,专家决策等功能.     

地下空间开挖流固耦合问题的国内外研究现状及发展趋势

岩体水力学由于岩土介质的复杂性,远未达到完善的程度,本文就地下空间开挖所涉及的流固耦合问题的研究现状从理论、模型及突涌水预测方法的角度展开叙述,介绍了目前国内外有关地下开挖中所涉及的流固耦合问题的研究现状,并对其发展趋势作了简单的陈述。     

电动RTG的开发与应用

轮胎式集装箱门式起重机(RTG)是国内外集装箱专业化码头堆场的主力设备.它以轮胎支撑方式运行,用柴油发动机输出动力,完成堆场集装箱的装卸、堆码作业.     

Autonomy, bureaucracy, professionalism and accountability: a transaction cost approach to shipboard controls

In recent years, shipping industry has encountered severe competition, technological change, and environmental and safety concerns. In order to remain competitive, firms need to review and redesign shipboard work. A crucial aspect of these efforts is shipboard controls that define the extent of autonomy and accountability of officers and crew. This study examines four types of controls on board ships. These are monitoring and autonomy, outcome accountability, formalization and professionalization. The study applied trancsaction cost theory to test eight hypotheses on board 16 ships in two companies. The results largely confirm theoretical predictions. Task visibility, complexity and uncertainty show strong relationships to the four types of controls. However, there are also significant gaps in that accountability for outcomes is low, and situation with regard to crew training and autonomy can be improved. Implications for human resource practice and future research are discussed.     

岸边集装箱起重机金属结构疲劳寿命研究

以岸边集装箱起重机为研究对象，研究在产品设计阶段对金属结构疲劳寿命进行预测的基本计算方法，并编制计算程序，对结构在一定工作条件下的疲劳寿命进行计算分析。     

深水半潜式平台大型生活区结构强度研究

结构安全是保证深水半潜式钻井平台在恶劣海况、复杂载荷作用下正常作业的基本前提,而大型生活区往往因参与平台总强度而发生结构损伤,开展对生活区危险区域结构强度和位置布置研究是半潜式平台安全作业运营的重要保障。采用随机性设计波方法确定波浪参数,开展含生活区的半潜式平台结构响应计算和变形分析,总结主导生活区高应力区域的典型波浪载荷工况。通过横向和纵向布置位置对比分析,总结生活区参与平台总强度的规律。结果显示,主导生活区结构强度的典型波浪载荷工况为中纵剖面扭矩和中纵剖面剪力工况;当生活楼前侧围壁与平台首部侧围壁齐平时,参与平台总强度程度较大;生活楼长度增加会增大其参与平台总强度程度;生活楼的长度应避免与平台立柱内侧板的间距相当;分析结果可为半潜式平台生活区设计提供技术支持。