200km/h六轴大功率客运交流传动电力机车概述

介绍了200 km/h六轴大功率客运交流传动电力机车的主要技术特点、性能参数、总体结构,以及通风系统、电气系统、机械系统、制动系统等子系统的技术方案。     

主变压器差动保护装置极性问题的探讨

阐述牵引变电所三相V/v接线牵引变压器差动保护极性的影响因素及其校验方法（微机保护的极性、主变压器的极性和电流互感器的极性3方面）,分析了包西线某牵引变电所主变压器设计和接线的缺陷,提出并验证了三相V/v接线牵引变压器差动保护接线方式的正确性。     

利用钢轮托车辅助盾构机过站施工技术

针对地铁盾构法施工中盾构机通过满足过站要求的已完工车站进行二次始发这一常见施工环节,介绍一种通过钢轮托车辅助盾构机空载推进实现过站需要的施工技术及相应施工要点,如盾构机过站的施工工艺流程,钢板、钢轮拖车及轨道的铺设等。论述了利用钢轮拖车辅助盾构机过站施工技术采取的质量控制、安全措施及环保措施,分析了采用该技术的经济、社会和环境效益。     

城市轨道交通车辆受电弓弓头安全宽度的计算

分析了城市轨道交通车辆在直线段和曲线段中受电弓弓头的偏移影响因素以及接触线的受风偏移现象.根据比较车辆处于直线段和曲线段时的受电弓与接触线之间相对距离来确定受电弓弓头宽度的合理安全宽度,并设计了“城市轨道交通车辆受电弓宽度参数计算软件”.     

变频器输出电压du/dt对电机的影响及其滤波器的设计

研究了变频器输出电压du/dt对电机端电压和轴承电流的影响,在PSpice中建立了电机高频模型,并对端电压波形进行了仿真;着重研究了一种du/dt滤波器的参数设计方法,并且进行了仿真和实验验证。实践证明,该滤波器具有较好的滤波效果。     

HXD1B型机车大螺栓的强度及预紧分析

文章介绍了HXD1B型机车大螺栓的安装结构及其作用,对大螺栓的轴向工作载荷、预紧力、强度等进行计算和校核,比较了力矩法、测量螺栓伸长法、应变计法等三种不同的预紧力控制方法的优缺点,提出影响大螺栓预紧力控制的各种因素并进行分析,最终确定适用于大螺栓的预紧力及其相应的控制方法.     

HX_D1C型机车砂箱撑管破损原因分析及改进措施

对HXD1C型机车砂箱撑管进行观察,发现其破损的原因是砂子的冲蚀磨损。分析撑管破损的机理,得出结论:撑管最先破损的位置发生在砂子冲击角度为30°的地方。提出撑管的改进措施,改进后的撑管运用状况良好。     

新线开通对线网客流特征的影响

随着北京市轨道交通的快速发展,每年的新线开通都将对线网各线的客流分布产生较大的影响,但新线可研多注重新线自身的预测,缺乏线网整体变化的预测分析.结合线网客流变化的关键因素,探索利用新线可研和现有OD数据预测新线开通后线网客流的方法,并以北京地铁4号线开通为例进行验证,从一定程度上证明该方法的可行性和适用性.     

Surf-riding and oscillations of a ship in quartering waves

The behavior of a ship encountering large regular waves from astern at low frequency is the object of investigation, with a parallel study of surf-riding and periodic motion paterns. First, the theoretical analysis of surf-riding is extended from purely following to quartering seas. Steady-state continuation is used to identify all possible surf-riding states for one wavelength. Examination of stability indicates the existence of stable and unstable states and predicts a new type of oscillatory surf-riding. Global analysis is also applied to determine the areas of state space which lead to surf-riding for a given ship and wave conditions. In the case of overtaking waves, the large rudder-yaw-surge oscillations of the vessel are examined, showing the mechanism and conditions responsible for loss of controllability at certain vessel headings.List of symbols c wave celerity (m/s) - C(p) roll damping moment (Ntm) - g acceleration of gravity (m/s²) - GM metacentric height (m) - H wave height (m) - I _x ,I _z roll and yaw ship moments of inertia (kg m²) - k wave number (m^–1) - K _H ,K _W ,K _R hull reaction, wave, rudder, and propeller - K _p forces in the roll direction (Ntm) - m ship mass (kg) - n propeller rate of rotation (rpm) - N _H ,N _W ,N _R hull reaction, wave, rudder, and propeller - N _P moments in the yaw direction (Ntm) - p roll angular velocity (rad/s) - r rate-of-turn (rad/s) - R(,x) restoring moment (Ntm) - Res(u) ship resistance (Nt) - t time (s) - u surge velocity (m/s) - U vessel speed (m/s) - v sway velocity (m/s) - W ship weight (Nt) - x longitudinal position of the ship measured from the wave system (m) - x _G ,z _G longitudinal and vertical center of gravity (m) - x _S longitudinal position of a ship section (S), in the ship-fixed system (m) - X _H ,X _W ,X _R hull reaction, wave, rudder, and propeller - X _P forces in the surge direction (Nt) - y transverse position of the ship, measured from the wave system (m) - Y _H ,Y _W ,Y _R hull reaction, wave, rudder, and propeller - Y _p forces in the sway direction (Nt) - z _Y vertical position of the point of action of the lateral reaction force during turn (m) - z _W vertical position of the point of action of the lateral wave force (m) Greek symbols angle of drift (rad) - rudder angle (rad) - wavelength (m) - position of the ship in the earth-fixed system (m) - water density (kg/m³) - angle of heel (rad) - heading angle (rad) - _e frequency of encounter (rad/s) Hydrodynamic coefficients K roll added mass - N _v ,N _r yaw acceleration coefficients - N _v N _r N _rr N _rrv ,N _vvr yaw velocity coefficients K. Spyrou: Ship behavior in quartering waves - X _u surge acceleration coefficient - X _u X _vr surge velocity coefficients - Y _v ,Y _r sway acceleration coefficients - Y _v ,Y _r ,Y _vv ,Y _rr ,Y _vr sway velocity coefficients European Union-nominated Fellow of the Science and Technology Agency of Japan, Visiting Researcher, National Research Institute of Fisheries Engineering of Japan     

钢管混凝土拱桥转体施工技术

对钢管混凝土拱桥施工过程中的竖转、平转体系构造，以及施工技术进行阐述，并对施工方法的特点进行分析，供同类桥梁施工借鉴。