MODEL AND SIMULATION FOR A BRUSHLESS AC GENERATOR WITH AROTARY RECTIFIER

Objective For a brushless AC generator with a rotary rectifier, it is necessary and significant to model and simulate at normal and fault operation states. Methods Two new concepts, namely, Simulink signals and PSB (Power System Blockset) variables, are proposed, and the difference between the two concepts is clarified. Based on the new model for synchronous machines, a simulation model for a brushless AC generator with a rotary rectifier is constructed by Matlab/Simulink/PSB. This new model, which has a speed input terminal and an exciting voltage input one, can simulate the real electrical characters and direct mechanical connection between two synchronous machines perfectly. The rotary rectifier is a three-phase full-wave bridge rectifier which consists of six diodes. The model for the diodes is a macro-model which possesses much better accuracy than an ideal one of switches. Results Based on the present model, some simulation results such as exciting current waveform, phase current waveform and phase voltbge waveform are afftained at several operation conditions. Conclusion The simulation for a brushless AC generator with a rotary rectifier is demonstrated at normal and fault operation states, respectively. The results confirm the presented method.     

高性能沥青路面（Superpave）的技术初探

采用旋转压实新技术,用PG等级和常规指标评价SBS改性沥青的技术性能。从原材料、配合比设计、现场施工等方面简略介绍了Superpave技术在沪蓉高速公路成都段的首次应用,为今后Superpave技术推广应用提供借鉴。     

上海南站综合客运枢纽的换乘诱导标识研究

首先通过对上海南站换乘现状的调查和对客运枢纽标识的深入研究,从综合客运枢纽换乘诱导标识的自身特点和旅客的行为特性的角度进行分析,旨在找出南站换乘诱导标识功能缺失的症结,为提高客运枢纽换乘标识的功能发挥寻求方向.同时,通过南站换乘寻路实验为例,基于具体换乘路线,按照分级诱导的原则,对上海南站换乘诱导标识特点加以评析,并提出相应的建议.     

THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1 000 Hz, rotating speed is from 60 rpm to 1 200 rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shafts speed.     

预瞄跟随理论和驾驶员模型在汽车智能驾驶研究中的应用

根据预瞄跟随理论及驾驶员的开车行为特性 ,指出汽车智能驾驶与驾驶员操纵行为的内在一致性——汽车智能驾驶系统的控制特性与熟练驾驶员的驾驶行为特性基本一致。结合驾驶员操纵行为模式将汽车智能驾驶系统划分为信息感知、轨迹决策和操纵控制三个部分 ,并一一加以具体分析 ,利用系统模糊决策理论对几种汽车行驶的典型工况进行了智能车辆方向控制仿真计算。理论分析和仿真结果表明预瞄跟随理论为智能车辆的研究提供了一个可行的研究途径 ,按照该理论建立的驾驶员方向控制模型可以直接应用于智能车辆控制算法的研究开发     

浅析我国注册会计师行业的未来发展之路

中国已经入世，会计市场即将全面开放，面对机遇和挑战，我们对中国的注册会计行业应有一个清楚的认识，认清问题之所在，才能迎接挑战，抓住机遇，只有锐意改革，不断开拓进取，巩固改革的基础，才能迎头赶上，迈出国门，走向世界。     

粉喷桩处理软土地基施工技术

粉喷桩加固软土地基的原理是：利用压缩空气携带着粉体固化材料，经过橡胶软管输送到钻头，借助叶片在旋转提升时产生的空隙喷出，喷出的混合气体在空隙中压力急剧降低，促使固化材料粘附在旋转叶片切开空隙的土中，地基土固化材料通过水泥的水解和水化作用、离子交换、硬化反应、碳化反应后，形成坚硬稳定的土体，从而达到加固软土地基的目的。其施工工艺流程见图1。     

河南省“十三五”公路水路发展阶段及趋势特征

基于交通运输发展相关理论,结合"十三五"河南省交通运输发展的需求特点,研究判断"十三五"时期河南省公路水路交通所处的发展阶段,分析该时期交通发展所呈现出的阶段性特征,明确未来河南省经济社会发展和人民生活对公路水路交通发展的新要求,把握全省公路水路交通下一步发展的方向和重点,为未来交通主管部门做好投资决策和制订发展规划等提供基础理论支撑。     

磁浮轴承系统的数学模型与控制分析

磁浮轴是一种依赖电磁力支承转子的新型无接触轴承,与传统油润滑轴承相比,具有许多优越性。介绍了磁浮轴承的基本原理和结构,在建立磁浮轴承一对径向定位电磁铁单自由度数学模型的基础上,对该不稳定系统进行了ＰＩＤ补偿控制,研究了控制器参数对系统稳定性的影响。     

飞越谜雾

汽车，火车，轮船，飞机等高速交通工具的出现，它们给人类带来了现代的生活节奏，奔波于拥挤的大都市的人们在享受着现代科技带来的高速与高效率的同时，却在上天赐予的“雾”面前大都停止了前进，一意孤行却使生命在一刹那的碰撞之间可能化为乌有。