隧道振动台模型试验的相似关系

以嘎隆拉隧道振动台模型试验为例,在模型试验相似理论的基础上对隧道振动台试验相似关系进行了研究;用方程分析法和量纲分析法推导了模型试验相似准则,实现了模型试验几何条件、边界条件、荷载及材料的相似,将其应用于隧道振动台动力模型试验;建立了有限元模型,从加速度时程曲线、频谱特性、加速度放大系数、破坏现象等方面与试验进行了对比。结果表明,试验结果与计算结果比较相符,破坏现象和破坏部位基本相似,说明本次相似关系的拟定是合理的。     

Extended bottlenecks, the fundamental relationship, and capacity drop on freeways

This paper presents evidence that the commonly used point bottleneck model is too simplistic for freeway bottlenecks, the actual mechanism appears to occur over an extended distance. We find evidence of subtle flow limiting and speed reducing phenomena more than a mile downstream of a lane drop bottleneck. These phenomena impact the fundamental relationship, FD. Close to the lane drop the free flow regime appears to come from a “parabolic” FD, but further downstream the relationship straightens to a “triangular” FD and throughput increases. We develop a theory to explain the underlying mechanisms. These insights should help resolve the decades long debate about the shape of the FD. The phenomena also provide a mechanism that may contribute to the empirically observed capacity drop often seen at bottlenecks. Although we study a lane drop, this work should be transferable to other bottlenecks where the capacity restriction persists for an extended distance, e.g., a corridor with a fixed number of lanes and an on-ramp bottleneck.     

三峡库区周期性库水位变化对抗滑桩加固效果非饱和流固耦合分析

三峡库区内广泛发育的滑坡等地质灾害在水库运行水位周期性波动条件下会发生复活乃至失稳。抗滑桩是其中应用广泛、效果良好的防治措施之一。抗滑桩在库水位周期性波动条件下对滑坡的治理加固效果及其自身的变形受力特征是较为重要但研究尚少的问题。采用非饱和岩土本构关系,考虑在库水位周期性波动条件下滑坡体处于饱和-非饱和周期性变化时的流固耦合效应,采用有限元法对设置抗滑桩前后库区某滑坡的位移和稳定状态进行模拟,并分析了抗滑桩内力及其桩顶位移随库水位变化的特征。研究结果表明,抗滑桩对滑坡的水平位移控制效果较为显著,安全系数最少能提高到2以上。在库水位运行的一个周期内,抗滑桩加固滑坡的安全系数变化幅度不超过5.4 %,而抗滑桩内力及桩顶位移不超过10.4 %。滑坡最小安全系数和抗滑桩最大受力出现在最高水位时,其变化趋势与水位变化趋势较为一致。     

供应链关系协调管理研究

提出了供应链管理研究中的一个新论点:供应链关系协调管理,并从供应链的复杂系统特性、供应链产生和发展的思想起源、企业环境、技术条件及供应链管理的研究历程、定义和供应链管理与传统管理模式的区别等多个方面进行了论证.在此基础上,给出了供应链关系协调管理的定义,讨论了供应链关系协调管理的框架性内容,给出了供应链关系协调管理的主要方法.     

高职汽车专业英语课程思政教学应处理好的几个关系

高职汽车专业英语课程思政教学要在保持课程自身特性基础上,针对教学难点,处理好教学目标多维要素之间、三个门类的教学内容比例、教师与学生之间,课程思政育人效果评价和汽车专业英语教学评价之间的四个关系,是实现思政育人目的的重要途径.     

Regulating the regulator: The impact of professional procuring bodies on local public transport policy and its effectiveness

During the past 15 years competitive tenders have become a common procedure when procuring local bus services in Europe. In particular, tenders with gross cost contracts and the so-called Scandinavian model have gained popularity, resulting in a vast amount of research on optimal contractual relationships between government and operators. This paper pays attention to a rather neglected part of the Scandinavian model: the construction of professional procuring bodies and their relationship to the local public administration, focusing on its implications for policy steering and service performance.The paper outlines briefly two different perspectives of analyses of organisational models: one perspective is anchored in principal-agent theory and institutional economics; and the other perspective in political science. Empirically, the article is based on an evaluation of the relation between two Norwegian counties and the administrative company responsible for planning and procuring public transport services. This evaluation indicates, firstly, important common challenges for the county administration due to lack of regional administrative competencies in relation to the administrative company, which also hampers the county’s role as coordinator of policy areas of importance for public transport. Secondly, due to increased transaction costs, the establishment of administrative companies does not seem compatible with contracts relying on net cost solutions with huge scope for operator initiatives.     

D.H.劳伦斯的"两极平衡"思想及其在两性观上的反映

劳伦斯的"两极平衡"思想是其哲学体系的一个重要方面,它独到深刻的内涵反映了劳伦斯对资本主义工业文明冲击下的社会现实的不断反思.劳伦斯的两性观亦以"两极平衡"思想为哲学基础,认为理想的两性关系是实现了"两极平衡"的关系.本文试从劳伦斯的"两极平衡"思想、"两极平衡"思想与劳伦斯的两性观,以及劳伦斯"两极平衡"思想形成的社会根源三个方面,就劳伦斯的"两极平衡"思想及其在他的两性观上的反映展开讨论,从而揭示劳伦斯及其作品中的深刻的社会批判意识.     

从胡锦涛主席访问印度看中印关系的发展走向

作为世界上两个最大的发展中国家,中国和印度的关系具有全球性意义.中印关系十分重大而复杂,两国存在历史遗留下来的问题;但在经济全球化的背景下,中印两国有着共同的战略利益和合作需要.胡锦涛主席访问印度使中印战略合作伙伴关系有了实质性提升,使双边关系进入全面发展的新阶段;中印两国不是对手,而是合作伙伴和朋友,虽然中印之间的历史和现实问题有待解决,但中印关系的发展前景光明.     

大学生人身伤害事故归责原则分析

高校在办学过程中发生的大学生人身伤害事故的解决主要取决于如何认定高校与大学生的法律关系及高校责任的归结问题.高校与大学生的法律关系不是单一的,包括教育行政法律关系、民事法律关系等,因此决定其归责原则体系应由过错责任原则、过错推定责任原则组成.提出解决大学生人身伤害事故的赔偿应实现市场化.     

AIS与罗经的相互关系和技术要求

此文探讨AIS与罗经的相互关系和技术要求,以及如何在船舶检验工作中加以应用,使船舶更好满足SOLAS公约及船检法规、规范的要求,供验船师、PSCO和相关技术人员参考。