受电弓-受流靴受流方式转换的研究

介绍受电弓和受流靴这两种受流器各自的优缺点及工作原理,并针对广州地铁4号线运行中的实际情况,提出了受流方式转换过程的技术要点,设计了一种由可编程序控制器（PLC）为控制核心的系统,该系统可控制地铁列车在两种受流方式之间的转换。     

交通基础设施BOT项目的界面管理

为了提高交通基础设施BOT项目管理水平,基于交通基础设施BOT项目的界面信息特点,指出了对该类项目进行界面管理的必要性.提出应从技术分析、组织体系和合同约束等角度,分析该类项目在全生命周期中存在的界面,探讨了界面管理在交通基础设施BOT项目的具体应用.     

高速机车牵引齿轮磨前滚刀齿形优化设计

通过对刀齿啮合关系的研究,地对高速机车牵引齿轮的应用和加工工艺特点,对高速机车牵引齿轮磨前滚齿形进行了优化设计,并可用计算机画出滚刀齿形和齿轮齿形。     

陶瓷沥青混合料路用性能试验研究

为解决大量废陶瓷堆积带来的环境问题,同时为提高沥青路面的抗滑性能,采用耐磨性能较好的陶瓷再生集料等体积取代部分石灰岩集料(替代率分别为0%、20%、40%和60%),研制陶瓷沥青混合料,开展陶瓷沥青混合料的路用性能研究,主要包括配合比设计、高温稳定性、水稳定性能,以及力学性能研究。试验结果表明:当陶瓷掺量不超过60%时,陶瓷沥青混合料的动稳定度,浸水残留稳定度,冻融劈裂强度比等各项性能指标均满足规范要求,路用性能良好。     

Port competition with accessibility and congestion: a theoretical framework and literature review on empirical studies

This review interprets recent studies of the interactions between the competition of gateway seaports and the accessibility of landside transportation links to inland regions. Port competition is treated as part of a rivalry between two transportation chains. This article identifies the main modeling approaches and defines the different types of hinterland access systems described in the literature. A general theoretical framework is then proposed to incorporate those key components. The importance of the proposed framework is revealed by comparing and extending results from the literature. Major assumptions that need further empirical verification are identified and discussed, and related empirical studies are reviewed. Finally, avenues for further research are discussed.     

基于现代新科技的新型救生艇开发

设计一种基于太阳能发电、自动识别系统(AIS)定位和热敏电阻(PTC)加热的新型救生艇。首先,设计救生艇太阳能辅助能源系统,包括太阳能电池板在救生艇上的安放及展开结构的设计,并结合典型航道光照强度进行发电量计算;然后,利用半导体制冷技术结合空气加湿-除湿技术设计救生艇空气造水系统,并应用MATLAB软件模拟海洋环境进行造水系统取水率的验算;同时,对比分析AIS-SART与雷达应答器的综合性能,为新型救生艇选配适当的应答器;最后,分析PTC加热材料的加热特性,结合救生艇的结构特点,选配适当的PTC加热材料,设计救生艇座椅加热单元,并进行PTC加热系统耗电量的理论计算。结果表明,该设计可以解决救生艇能源较少、淡水有限、定位精度低及保温性差等问题,能够提高乘员的舒适性以及延长等待救援的时间。     

Axial Response of a Compression Pile to Nearby Excavation北大核心CSCD

One of the major concern in the excavation in soft soil areas is the effect of soil movement on adjacent pile foundations. In this paper, three-dimensional finite element models are established to study the axial response of the adjacent pile foundations close to an excavation in soft soil. The results show that, due to the nearby excavation, the axial bearing capacity of a single pile under compression decreases about 13.6%, and considerable additional settlements of a single pile subjected to the working compression load are generated. Therefore, the characteristics of load transfer mechanism between pile shaft and around soil, as well as the tip soil reaction are investigated extensively, which demonstrates that, as expected, the nearby excavation leads to a reduction of ultimate soil friction resistance. Furtherly, the widely employed load transfer method for pile foundation is modified to consider the effects of nearby excavation, which can be employed to predict the axial response of an axially loaded pile foundation beside an excavation. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Internalization of port congestion: strategic effect behind shipping line delays and implications for terminal charges and investment

This paper develops a theoretical model to analyze the congestion internalization of the shipping lines, taking into account the ‘knock on’ effect (i.e. the congestion delay passed on from one port-of-call to the next port-of-call). We find that with the presence of the knock-on effect, liners will operate less in terminals, and an increase of a liner’s operation in one terminal will decrease its operation in the other. If the liners are involved in a Stackelberg competition, whether they operate more or less in a terminal under the knock-on effect depends on the comparison between the marginal congestion costs of terminals. Furthermore, we find that the coordinated profit-maximizing terminal charges are higher than both the socially optimal terminal charges and the independent profit-maximizing terminal charges. When the knock-on effect is small, the independent profit-maximizing terminal charges are set at higher levels than the socially optimal terminal charges; but when the knock-on effect is sufficiently large, this relationship may reverse. Besides, the capacity investment rules are the same for welfare-maximizing terminal operator and coordinated profit-maximizing terminal operator, while independent profit-maximizing terminal operators invest less in capacity. The larger the knock-on effect, the larger this discrepancy.     

Numerical simulation of the solitary wave interacting with an elastic structure using MPS-FEM coupled method

Fluid-Structure Interaction (FSI) caused by fluid impacting onto a flexible structure commonly occurs in naval architecture and ocean engineering. Research on the problem of wave-structure interaction is important to ensure the safety of offshore structures. This paper presents the Moving Particle Semi-implicit and Finite Element Coupled Method (MPS-FEM) to simulate FSI problems. The Moving Particle Semi-implicit (MPS) method is used to calculate the fluid domain, while the Finite Element Method (FEM) is used to address the structure domain. The scheme for the coupling of MPS and FEM is introduced first. Then, numerical validation and convergent study are performed to verify the accuracy of the solver for solitary wave generation and FSI problems. The interaction between the solitary wave and an elastic structure is investigated by using the MPS-FEM coupled method.     

波形钢腹板人行桥的有限元分析

波形钢腹板PC组合箱梁结构恰当地分别利用了混凝土的高抗压强度和钢材的高抗剪能力,提高了材料的使用效率,具有广阔的应用前景.本文对我国第一座波形钢腹板PC箱梁桥建立有限元模型,分析了顶、底板和钢腹板的应力应变.