与集中质量和弹簧连接的均匀弹性杆的振动

讨论并求解一端系有集中质量且两端均与弹簧连接的均匀弹性杆振动问题.当弹簧劲度系数为零时,利用极限方法得到一端自由另一端系有集中质量的弹性杆振动问题的解.     

土工织物在长江界牌航道整治工程中的应用

通过长江界牌航道整治工程实例介绍土工织物在航道整治工程中的应用情况。     

用地性质与线路区位对社区公交的影响研究

社区公交的开通可有效缓解乘客出行的"最后一公里"问题,合理的站点布局可提高社区公交的客流量、促进公共交通发展。基于交通实地调查、SP调查和RP调查,对郑州市社区公交现状进行分析,分别对出行者的性别、年龄、家庭人口数、月收入、职业、出行目的进行特征分析。考虑用地性质和线路的区位影响,分别对社区公交的客流量和乘坐社区公交前使用的交通方式进行研究,分析其对社区公交的站点布设、两站点间的距离、发车间隔和发车频率等的影响,为社区公交的布设提供依据,增加社区公交的竞争力,更好地满足社区居民的出行需求。     

郊域轨道交通对土地利用演变的影响分析

选择贝叶斯网络(Bayesian Network, BN)对郊域轨道交通引起的土地利用演变规律(Land Use Change，LUC)进行研究。将影响范围外设为参照区分析LUC是否因郊域线出现差异，并与 市郊线进行对比。东京都的案例结果表明，郊域线对LUC产生了影响，其中，影响较大的是森林、 建筑与运动竞技用地(运营期)及森林、运动竞技与水域(开通前)地块，上述地块缓冲区与参照区的 差异依次是-32.08%，12.59%，8.24%与-24.23%，4.62%，4.40%；然而市郊线未产生影响，说明不同 于市区LUC的多驱动力，郊域线作为郊区LUC的强驱动力，引起的LUC变化显著，可为通过建设 郊域线推动郊区土地发展提供依据。由于市区土地发展成熟，土地利用(Land Use，LU)延续性 好，故市郊线当期总与前期LU有直接关系；郊域线作为郊区LUC的强驱动力，运营后引起LUC 活跃程度比较大，故导致运营期与前期 LU 无直接关系，可为郊域线土地开发时期提供参考依 据。BN推理显示，郊域线运营期缓冲区终态为建筑地块受建筑用地聚集程度影响低于参照区， 说明郊域线运营期终态为建筑地块的演变较独立，同样是由郊域线引起LUC活跃程度比较大引 起的；为支持郊域线运营期地块终态为建筑用地，区域需87.2%的概率为缓冲区，初始邻域用地需 98.5%为非森林地块，以上可为郊域线土地开发中建筑用地布局与选址提供参考依据。以多摩线 2006年LU作为初始态，预测2014年LU，结果精度达89.9%，表明BN具有较强的推理能力。最 后，挖掘轨道交通LUC机制，即其通过提高出行可达性影响人们愿意在其周边居住与生活，因此 出现缓冲区用地演变现象，并据此阐释了郊域线的LUC机制。     

Bending behavior modeling of unbonded flexible pipes considering tangential compliance of interlayer contact interfaces and shear deformations

Rigorous analytical formulations are given to describe the gross slip initiation and progression in tensile armor layers of unbonded flexible pipes. Then two mechanisms are thought to contribute to the decrease of layer stiffness before gross slip begins. The first one considers the micro-slip occurred at the interlayer contact interfaces. The relative displacement between an armor wire and the underlying layer is determined according to the theory of contact mechanics. Shear deformations of the supporting plastic layer are taken into account in the other mechanism where plane sections no longer remain plane. The results of bending moment-curvature relationship from the presented models are compared with the available test data and good correlations are found. The shear model is seen to describe the slip transition better than other models do.     

Distinguishing the land use effects of road pricing based on the urban form attributes

This paper studies the effects of road pricing on land use under different development scenarios (business as usual scenario and transit oriented development scenario) by a quantitative method, which combines the integrated land use and transport interaction model (TRANUS model) with the scenario-planning techniques. Moreover, in order to further analyze the differences of the land use effects of road pricing on traffic analysis zones (TAZs) with different urban form attributes, a quantitative classification method combining factor analysis and cluster analysis is then used to quantitatively classify TAZs. The results demonstrate that the effects of road pricing on the land use of a specific region depend on the urban form attributes of the region. The higher the densities of employments and population, and better street design (high densities of street and intersections) and public transportation condition, the less the region is negatively affected by road pricing, and vice versa. More importantly, rail transit can alleviate the negative impact of road pricing on commercial development and population concentration of the region. Therefore, before introducing a road pricing policy, it is necessary to develop public transport system, especially rail transit.     

An activity pattern – destination land use choice model of low income households of informal settlements – Case study of Delhi

Various transportation studies carried out in India, while estimating the travel demand, do not take into consideration the travel characteristics of different income groups. The conventional transportation travel demand model lacks the ability to address the travel needs of the urban poor. This paper explores the factors influencing the travel destinations of urban poor living in informal settlements and finds that travel times have a significant negative impact on the choice to travel and influences the choice of the destinations. The study also finds that the inhabitants of informal settlements are adversely affected by urban policies that displace them and rehabilitate them far from their employment opportunities and that the travel characteristics of low income households living in informal settlements are significantly different from higher income households.     

地铁站点客流特征与土地利用关系研究

讨论轨道交通站点客流的时间变化规律,根据客流的时序特征,利用时间序列聚类的K-means算法对轨道交通站点进行分类,对比不同类别站点的客流差异,同时探究轨道交通站点早晚高峰进出站客流与站点周围用地密度之间的相关关系,在考虑空间相关性的基础上,采用地理加权回归定量计算回归方程,详细分析客流与用地之间的相关系数在空间的分布情况。通过分析为不同站点制定有针对性的运营管理措施,以及为轨道交通规划提供理论支持。     

厚壁管道内部缺陷的超声柔性探头仿真分析

根据超声柔性探头的原理,介绍了柔性探头的成像模型3针对核电站等领域广泛使用的不锈钢厚壁管道,基于CIVA无损检测仿真软件,建立了厚达72.3 mm的厚壁管道模型,分别仿真了柔性探头及刚性探头在检测裂纹、分层及夹杂3种管道常见缺陷时的缺陷响应,定性及定量的比较了2种探头检测结果的区别.结果表明:柔性探头在检测厚壁管道等曲面形工件的10 mm×2mm、倾斜的横向裂纹,5 mm×5 mm的分层缺陷和直径4 mm、内部为铝的夹杂缺陷时具有较大的优势.     

减少小汽车出行的波特兰多方式交通体系建设

基于对美国波特兰大都市区交通与土地利用相关规划及政策文献的梳理,剖析了波特兰都市区构建多方式交通体系所采取的主要规划思想、政策手段及创新实践。指出波特兰都市区多方式交通体系建设的核心思想是减少对小汽车出行的依赖,并通过人均车公里等量化指标衡量、评估这种依赖程度的变化。同时,辅以城市增长控制、交通与土地利用整合以及广泛的公众参与和机构协调等政策,转变对小汽车交通发展的认识,加强交通需求管理。此外,极力提升公共交通、自行车和步行交通的品质,并就不同交通方式间的衔接换乘进行整合,从而使波特兰交通系统朝既定的多方式目标稳步推进。