基于拉线机构的机器鱼运动控制仿真研究

研究机器鱼是为了模仿鱼类的游动方式,研究出更为高效、灵活的水下航行器。文中介绍了一种基于拉线机构的机器鱼,主要介绍了对拉线机构应用在机器鱼推进上的仿真分析和控制。对拉线机构的鱼尾进行了仿真分析,并对比真实鱼类游动时的体干波曲线。仿真结果显示：基于拉线机构的机器鱼与传统的多关节串联驱动的机器鱼相比能更好地模拟真实鱼类的游动。制作了机器鱼样机和控制系统,用于进一步分析研究基于拉线机构的机器鱼的性能。     

Warning standards study of real-time monitoring for anti-collapse in large cross-sefction tunnel of soft and weak surrounding rockEI北大核心

Research purposes: The statistics for tunnel disasters showed that the quantities and casualties of tunnel collapse are much higher than other tunnel disasters. Achieved warning before collapse in tunnel construction, can greatly reduce the tunnel collapse hazards. The key to achieve anti-collapse warning in soft and weak surrounding rock tunnel is to obtain anti-collapse warning standards. Therefore, it is necessary to study tunnel anti-collapse warning standards to guide safe tunnel construction. Research conclusions: (1) Deformation of the tunnel is relevant to hydrogeological conditions, construction method, construction progress and other factors. Currently, the standard values in criterion were not suitable for tunnel collapse warning. (2) It is practicable to achieve anti-collapse monitoring by relative deformation, because anti-collapse real-time monitoring focused on dome relative deformation differently from routine monitoring in soft and weak surrounding rock tunnel. (3) The reference value of tunnel anti-collapse real-time monitoring is determined by displacement limit value in criterion, the maximum value of the measured displacement in similar project and the measured data in tunnel project. (4) The field experiment indicated that the reference value could meet tunnel anti-collapse warning. Therefore, the research results can be applied to large cross-section tunnel of soft and weak surrounding rock.     

汽车底盘护板的空气动力特性探讨

因汽车底部的不平整,空气阻力随车速增加而增大,影响车辆的行驶动力性和燃油经济性;高速转弯时升力变大影响汽车的操纵稳定性和安全性.本文设计一种符合空气动力学形状的功能性底盘护板,建立这种功能性护板的物理模型,这种结构保证燃油经济性基础上产生向下方向的压力,提高汽车行驶的操纵稳定性和安全性;提出加装功能性护板后气流经过底盘处解决方案,综合考虑在实际使用中燃油经济性问题.     

钢-混凝土组合深梁填充钢框架动力弹塑性分析

钢-混凝土组合深梁填充钢框架是一种新型抗侧力结构体系.用有限元分析软件SAP2000对6层钢框架和6层钢框架填充组合深梁进行了动力非线性时程分析,得到结构的顶点位移、基底剪力、层间位移角、楼层位移及塑性铰发展情况.通过对比分析发现,钢框架内填深梁以后,结构刚度和承载能力增强,且深梁首先破坏,保证钢框架安全,充分起到了抗震第一道防线的作用.     

长江小南海枢纽施工二期导流明渠通航条件研究

根据小南海枢纽河段河势及水流条件特点,通过水工模型试验和船模试验相结合的方法,分析了小南海枢纽施工二期导流明渠通航条件及存在问题,提出了明渠进口段炸除碍航礁石、出口段开挖新航槽的优化方案。研究表明:导流明渠原设计方案明渠进、出口段礁石碍航严重,通航水流条件差;优化方案通过整治措施显著改善了导流明渠的通航条件,保障了小南海枢纽施工二期长江上游航运的安全畅通。     

粗糙集和贝叶斯网络融合故障诊断方法

融合贝叶斯网络和粗糙集对不确定故障诊断的优势,以及粗糙集对冗余信息的处理能力,给出了一种粗糙集和贝叶斯网络进行融合的装备故障诊断方法,获得最小属性集的贝叶斯网络故障诊断模型及诊断规则,并应用于某型机载电台装备中进行验证,结果表明该方法不仅有效,而且得到的诊断规则也比单纯应用贝叶斯网络要优。     

关于二维平面圆柱涡激振动的数值模拟

利用有限元软件Adina建立平面二维圆柱绕流的数值模型,模拟低雷诺数条件下流体与圆柱间的涡激振动。随着流速加大,圆柱振动经历非锁定一锁定一脱离锁定的过程,由于锁定形态下圆柱振动与尾涡脱落引起的流体力形成共振,使圆柱的振幅增大。仅考虑圆柱顺流向振动时,横流向振幅略有增加;同时考虑圆柱在平面内的旋转和顺流向振动时,横流向振幅显著增加、锁定区间加宽,且质量比越低变化就越明显。     

Auction-Based Congestion Pricing

Abstract

Planners, engineers and economists have introduced various demand management methods in an attempt to reduce the fast growing traffic congestion. The basic idea behind various demand management strategies is to force drivers to travel and use transportation facilities more during off-peak hours and less during peak hours, as well as to increase the usage of underutilized routes. In this paper, a new demand management concept – Auction-based Congestion Pricing – is proposed and modeled.     

路面除冰融雪新技术探讨

近几年来,我国冬季因路面冰雪灾害频发交通事故,已造成巨大损失.本文主要描述了目前国内路面除冰雪技术现状,介绍了路面除冰融雪新技术的技术原理,并经过一系列室内试验和道路试验验证其各方面的性能.综合表明,新材料涂层的环保性良好,既不影响路面摩擦系数,也不与冰层相粘附,除冰融雪能力较佳,真有明显的实际应用价值.     

基于装配约束转换的虚拟装配系统中树视图结构的创建

针对现有的虚拟装配模型信息表达方法不完整,建模难度大和装配模型存在的不足等问题.提出了基于装配约束转换的骨架模型理论,然后以该骨架模型的结构作为思想基础,以VC＋＋6.0为编程工具开发,运用MFC中的CTreeView类来实现树视图的构建及节点的动态插入、节点的动态删除和节点的拖曳等功能,使产品装配模型的装配次序及装配结构在直观上得到完整的表达.