物流通道的空间溢出效应检验——基于中国11 条物流通道的实证

以中国11 条物流通道为实证对象,综合测算物流通道技术水平,构造基于地理距 离的空间邻接权重矩阵,检验相关变量的空间自相关性,构建空间杜宾面板数据模型验证了 中国物流通道的空间溢出效应.研究表明：中国物流通道总体上具有显著的正向空间溢出效 应,但从分布于不同空间的物流通道看,长江、沿海、京九、陇海兰新和沪昆物流通道正向空间 溢出效应显著;而京沪、京广和宝昆物流通道研究期内空间溢出效应不显著.我国物流通道的 空间溢出效应具有显著的空间差异,应因地制宜地合理化建设物流通道.     

南汇嘴边滩地形演变及其分析

南汇嘴边滩处于长江口和杭州湾的交接地带,受长江口和杭州湾北岸两股往复性潮流的控制,特定的水动力泥沙环境,决定了南汇嘴边滩长期以来的演变特点:边滩发育基本稳定;边滩外形基本保持不变;主要呈整体向东南方向移动的趋势。根据已有的1998~2005年断面数据资料分析了南汇嘴附近海域近期的地形演变情况,并对其影响因素——动力因素、泥沙絮凝、长江入海水沙变化以及近岸水利工程建设进行了分析。     

多波束测深系统在河床变化分析中的应用

河道变化情况与变化趋势是河道防洪、通航、水文等分析的重要因素。特别是在河道水情复杂和险工险段处，其河床变化复杂，规律难寻，对通航安全、防洪排涝、水利工程设施稳定性等影响深远。根据具体实测数据研究了多波束测深体系在河床变化分析中的应用，探索了多波束测深系统在内河河底地形数据采集及数据处理及分析的方法，形成了一种基于多波束测深系统的河底地形数据进行河床变化的反演分析的思路。     

Mechanical model and characteristics of deep-water drilling riser-wellhead system under internal solitary waves

Internal solitary waves with a huge amount of energy easily trigger the large dynamic responses of riser-wellhead system and threaten its structural safety. However, previous studies have only focused on the dynamic response of the riser under internal solitary waves. The riser may experience excessive traction from the platform, especially from the mooring platform, in response to the arrival of internal solitary waves. The bottom of the riser connects to the wellhead system, which in turn exerts a reaction force on the riser. To address this problem, a coupled dynamic model of deep-water drilling mooring platform-riser-wellhead system under internal solitary waves is developed in this paper. A dynamic response analysis method based on the fourth-order Runge-Kutta method and finite element method is also proposed for the mooring platform-riser-wellhead system. A dynamical solver for the coupled system is then developed using MATLAB. The dynamic response characteristics of the riser-wellhead system under internal solitary waves are calculated. Results show that the displacement and bending moment of the system initially increases and then decreases along with the propagation of internal solitary waves, and finally reach equilibrium position. The displacement and bending moment reach their peak before the trough of internal solitary waves passes through the riser-wellhead system. The dynamic responses of the riser-wellhead system under the influence of internal solitary wave loads are much larger than those without the effect of internal solitary wave loads. The riser system experiences shearing loads at the interface of internal solitary waves, which trigger a step-like bending moment variation. The bending moment of the conductor under the mudline is greatly increased by the internal solitary waves.