船用柴油机相继增压气动蝶阀切换时间研究

建立柴油机相继增压蝶阀气动控制系统的物理模型,并应用气压传动系统动力学理论建立蝶阀控制系统数学模型;然后利用MATLAB/Simulink编制的仿真程序对蝶阀转换过程进行仿真计算,结果得出了影响蝶阀切换时间的主要因素及影响规律;最后搭建了蝶阀气动控制系统的试验台,通过试验结果和仿真结果的对比,验证了仿真结果的可靠性;为深入了解蝶阀控制系统的特性提供了理论依据.     

Train rescheduling model with train delay and passenger impatience time in urban subway network

This paper considers the train rescheduling problem with train delay in urban subway network. With the objective of minimizing the negative effect of train delay to passengers, which is quantified with a weighted combination of travel time cost and the cost of giving up the planned trips, train rescheduling model is proposed to jointly synchronize both train delay operation constraints and passenger behavior choices. Space–time network is proposed to describe passenger schedule‐based path choices and obtain the shortest travel times. Impatience time is defined to describe the intolerance of passengers to train delay. By comparing the increased travel time due to train delay with the passenger impatience time, a binary variable is defined to represent whether the passenger will give up their planned trips or not. The proposed train rescheduling model is implemented using genetic algorithm, and the model effectiveness is further examined through numerical experiments of real‐world urban subway train timetabling test. Duration effects of the train delay to the optimization results are analyzed. Copyright © 2017 John Wiley & Sons, Ltd.     

TCP缓释陶瓷材料的研究

以无定型磷酸三钙为基体，通过加入微量元素Cu,制备出具有缓释作用的陶瓷材料。通过不浸实验和XRD研究了缓释陶瓷的金融离子Cu释放速度以及陶瓷材料的微观结构。     

Performance comparison between pedestrian push-button and pre-timed pedestrian crossings at midblock: a Korean case study

Walking has been highlighted as an independent transportation mode as well as an access/egress mode to/from public transit to encourage the use of more sustainable transport systems. However, walking does not seem to have priority over other transportation modes, especially in areas where various modes of movement are in conflict. The pedestrian push-button system seems to be a solution to distribute the right of way. The focus of this study is on the performance issue of the pedestrian push-button. Specifically, this study deals with issues related to mid-block crossings and attempts to answer two questions: whose waiting time is longer at pre-timed and push-button crossings, pedestrians, or vehicles? and which system – pre-timed or push-button – is better in terms of total waiting time? According to our simulation analyses, if the pedestrian flow rate is less than 120, 85, and 70 ped/h for two-, three-, and four-lane roads, respectively, the push-button system is recommended.     

Delay Restoration of Single-Track Railway Rescheduling

On the basis of analysis of the principle of delay restoration in a disturbed schedule, a heuristic algorithm for rescheduling trains is developed by restoring the total delay of the disturbed schedule. A discrete event topologic model is derived from the original undisturbed train diagram and a back propagation analysis method is used to label the maximum buffer time of each point in the model. In order to analyze the principle of delay restoration, the concept of critical delay is developed from the labeled maximum buffer time. The critical delay is the critical point of successful delay restoration. All the disturbed trains are classified into the strong-delayed trains and the weak-delayed trains by the criterion of the critical delay. Only the latter, in which actual delay is less than its critical delay, can be adjusted to a normal running state during time horizon considered. The heuristic algorithm is used to restore all the disturbed trains according to their critical details. The cores of the algorithm are the iterative repair technique and two repair methods for the two kinds of trains. The algorithm searches iteratively the space of possible conflicts caused by disturbed trains using an earfiest-delay-first heuristics and always attempts to repair the earliest constraint violation. The algorithm adjusts the weak-delayed trains directly back to the normal running state using the buffer time of the original train diagram. For the strong-delayed trains,the algorithm uses an utility function with some weighted attributes to determine the dynamic priority of the trains, and resolves the conflict according to the calculated dynamic priority. In the end, the experimental results show that the algorithm produces ＂good enough＂ schedules effectively and efficiently in disturbed situations.     

世界银行贷款项目“卫津路拓宽工程”的经济效益计算

本市以天津城市主干道卫津路拓宽改造工程为例，论述城市道路经济效益计算方法。按全天高峰小时、非高峰小时，分别计算机动车和非机动车的运营成本、时间价值及事故费用，采用有、无项目对比法．进行经济效益计算。经济效益中以车辆行程时间延误与路口时间延误的节约作为主要效益。     

Auto-ignition and micro-explosion behaviors of droplet arrays of water-in-fuel emulsion

The characteristics of auto-ignition and micro-explosion behaviors of one-dimensional arrays of fuel droplets suspended in a chamber with high surrounding temperature were investigated experimentally with various droplet spacings, numbers of droplet and surrounding temperatures. The fuels used were pure n-decane and emulsified n-decane with varied water contents ranging from 10 to 30%. All experiments were performed under atmospheric conditions with high surrounding temperatures. An imaging technique using a high-speed camera was adopted to measure ignition delay, flame lifetime, and flame spread speed. The camera was also used to observe micro-explosion behaviors. As the droplet array spacing increased, the ignition delay also increased, regardless of water content. However, the lifetime of the droplet array decreased as the droplet spacing increased. The micro-explosion starting time remained unchanged regardless of the number of the droplets or the droplet spacing; however, it tended to be delayed slightly as the water percentage and droplet spacing increased.     

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简单输入输出模型与冲击波分析是研究交通瓶颈问题的两种常用方法,本文着重分析两者的一致性。在数学推导中考虑到达需求与流出率的变化时,两者对于排队和延误的预测结果是一致的。在不同的交通和边界条件下,两者在拥堵形成至消散的任意时刻所得排队长度,拥堵时间等结果均是一致的。以往认为两种方法不一致的研究忽略了一些与背景交通密切相关的基本因素。实例分析说明正是这些基本因素使得这两种分析方法在不同流量－密度关系下都具有一致性。     

基于 M/G/1模型的停车场出口排队延误

通过对大型停车场高峰时段出口车辆行驶特性的调查研究,选取了车辆排队的出口车头时距以及出口服务时间两个指标。基于两个指标实测特性和 M/G/1排队模型的分析,计算了停车场出口理论平均排队时间。通过实测车辆平均排队时间,对理论模型计算的平均排队时间进行了修正。实例分析表明：排队时间修正模型能够准确地估计排队时间。提出了基于驾驶员容忍度的排队延误分级标准。