净化消声器压力损失计算方法

本文综合运用流体力学、热力学及化学有关理论,对柴油机用的净化消声器的压力损失算法进行推导及试验验证,为在净化消声器设计阶段预测净化消声器对发动机性能的影响提供了可用的手段。     

Phase change analysis of an underwater glider propelled by the ocean's thermal energy

The phase change characteristic of the power source of an underwater glider propelled by the ocean's thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process,but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees,the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change,and the slope of the temperature time history curve remains the same. However,the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size,boundary conditions,and the power source's cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38mm needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems.     

ISS-based robust adaptive fuzzy algorithm for maintaining a ship's track

This paper focuses on the problem of linear track keeping for marine surface vessels. The influence exerted by sea currents on the kinematic equation of ships is considered first. The input-to-state stability(ISS) theory used to verify the system is input-to-state stable. Combining the Nussbaum gain with backstepping techniques,a robust adaptive fuzzy algorithm is presented by employing fuzzy systems as an approximator for unknown nonlinearities in the system. It is proved that the proposed algorithm that guarantees all signals in the closed-loop system are ultimately bounded. Consequently,a ship's linear track-keeping control can be implemented. Simulation results using Dalian Maritime University's ocean-going training ship 'YULONG' are presented to validate the effectiveness of the proposed algorithm.     

小郭巨渔港工程防波堤平面布置方案

波浪是渔港建设中最重要的水动力因素,由于外海风浪作用强烈,影响港内渔船泊稳,需修建防波堤挡潮抗浪。从波浪角度研究防波堤平面布置,首先分析了舟山市六横岛小郭巨渔港工程的建设条件,确定防浪掩护控制标准,并提出防波堤直线形、折线形布置的8个平面布置方案。以满足渔船有效泊稳面积为准,采用MIKE21 BW模块计算在50 a一遇波浪与水位组合条件下堤后波高分布及防浪掩护效果,对8个方案进行研究,基于其中相对较优方案,进行了2个方案的优化。最终确定某渔港防波堤平面布置最优方案为:防波堤总长350 m、折堤夹角132°、直线段长122 m、折线段长228 m。     

基于GIS/GPS的高速公路车辆追尾预警系统研究

分析了高速公路车辆追尾事故的原因,研究了车辆安全制动距离,综合驾驶员跟驰与车辆制动模型得到安全距离函数,提出一种基于GIS/GPS的高速公路车辆追尾预警系统框架,建立了车辆报警流程图。该系统有利于预防追尾事故,提高高速公路安全。     

城市道路交通系统频谱分析方法及应用

对实际道路交通系统特征的研究是通过分析布设在路网中不同地点大量交通信息采集设备采集的数据来进行的。交通信息采集是对城市道路交通系统在时间和空闻上一个采样过程,其数据具有时问和空间属性．本文系统地建立了一种城市道路交通系统频谱分析方法。对于时间采样,通过功率谱分析认为：不同的数据采样间隔,获得的交通信息不同,从而分析出的...     

轨道交通列车运行延误仿真系统研究

简述了轨道交通列车运行延误仿真系统的基本框架结构;对列车延误模拟分析和运行模拟两个主要模块的模型建立、结构设计、功能实现及算法结构进行了描述.对列车延误仿真的评价指标进行了说明.系统可根据基础设施特点、列车运行组织方案、列车运行图以及列车运行延误的影响等,进行运行组织方案的可靠性、适应性及预期效果的定量分析和评价.     

中国、俄罗斯地铁规划及相关预埋建设的对比

考察了俄罗斯地铁,结合城市轨道交通线网规划、运营管理工作,分析规划指标、建设预留与运营效益关系的规律,对比两国的差异,探讨适合中国国情的线网模式,以及决策、建设与线网功能的关系。     

《地铁设计规范》问与答(21)

问题57 《地铁设计规范》第6.2.1条规定:"正线及辅助线钢轨应依据近、远期客流量,并经技术经济综合比较确定,宜采用 60kg/m钢轨,也可采用 50kg/m钢轨."