α径迹法用于分辨高浓铀和Pu微粒的方法研究

擦拭样品微粒分析技术是核保障环境样品分析的一种主要手段，从大量灰尘颗粒中识别并定位含高浓铀（HEU）或含Pu微粒是微粒分析首先需要解决的问题。本文以HEU和Pu微粒为研究对象，建立了用于微粒α径迹测量的样品制备方法，采用CR-39固体径迹探测器为α径迹探测器，测量了不同蚀刻时间2种微粒产生的α径迹星的径迹参数。结果表明：可通过测量径迹短轴与曲率直径并作图来分辨HEU和Pu微粒，该方法对于蚀刻时间大于10 h的微粒径迹星，均能明显分辨，对于径迹非常密集的径迹星，也能准确分辨。     

地铁列车-嵌入式轨道系统动力学性能研究I：理论建模、试验分析及验证

嵌入式轨道作为一种减振降噪轨道结构型式，通常是基于城市街道路面的低地板有轨电车系统设计的，而嵌入式轨道的连续支承特性及其减振降噪优点使其在地铁中具有较好的应用前景。嵌入式轨道在地铁中应用，将面临更高运行速度、更大轴重、更复杂线路条件等挑战，地铁列车-嵌入式轨道系统的动力学行为有待研究。建立地铁列车-嵌入式轨道系统的动力学模型，模型包括轨道系统模型、列车系统模型以及轮轨相互作用模型。其中，轨道子系统为嵌入式轨道系统，是建模和研究的重点。模型考虑了TIMOSHENKO钢轨模型、等效弹簧-阻尼单元支承的柔性轨道板模型、以及钢轨周围的填充材料模型，填充材料模型采用考虑质量的黏弹性弹簧-阻尼单元来模拟以考虑填充材料的惯性、弹性和阻尼特性。在我国首例运用于地铁的嵌入式轨道试验线开展了动力学性能试验研究，基于试验分析了动力学性能并通过试验验证了动力学模型的有效性，建立的分析模型和相关结论为嵌入式轨道结构在我国地铁的应用提供了理论基础和参考。     

Thermal Neutron Monitoring Using Cellulose Nitrate Track Detector by Means of Spark Counter

Cellulose nitrate films were examined for thermal neutron monitoring in contact with several kinds of (n, α) converter materials such as a plastic sheet doped with 1% boron, a solidified boron oxide plate, a single crystal plate of boron oxide and that of lithium fluoride. After thermal neutron irradiation in a research reactor, the films were etched in alkaline solution. The etch-pits on the films were counted with a spark counter. The single crystal converter of lithium fluoride was found to be the most sensitive for thermal neutron. A method for producing the single crystal converter was described. Linear relation between thermal neutron fluence and spark counts was found to be in the fluence range of 2 × 10^?6–3 × 10⁷n/cm² in case of using a lithium fluoride single crystal converter.     

CRTS Ⅰ型无砟轨道道床板裂缝成因分析及应对措施

针对CRTS Ⅰ型双块式无砟轨道道床板混凝土易开裂的问题,通过对实体结构调查,阐释了道床板混凝土的各种裂纹形式及其成因,并从设计、材料和施工3个方面提出了降低道床板混凝土开裂风险的技术措施。针对极端大风干旱地区环境特点,提出采用双掺保水-预蓄补水组分配制道床板自养护混凝土的技术思路,以期实现混凝土塑性阶段保水和硬化阶段内部持续补水的自养护功效,进而降低其开裂的风险。     

地铁不均匀沉降地段的轨道类型比选分析

简要总结了地铁不均匀沉降易发生的地段、原因及不利影响,对有砟轨道、普通无砟轨道、钢弹簧浮置板、隔振垫浮置板及梯形轨枕轨道等常用轨道类型对不均匀沉降的适应性和相关技术特点进行了全面分析,梯形轨枕在自身抗弯能力、空吊的检测和整治方便性、排水、施工速度、铺设精度等方面均具有优势,对不均匀沉降的适应性最好。     

Urban rail track condition monitoring based on in-service vehicle acceleration measurements

Condition monitoring of railway tracks is essential in ensuring the safety of railway systems. Traditional track recording vehicles (TRV) can only carry out the track inspection in the midnight after all the service vehicles are off duty. One track line can be inspected only once or less in a month. The severe track condition degradation cannot be detected timely and there is potential safety hazard for the railway system. Therefore, the track condition monitoring based on in-service vehicle has been paid more attention in the recent years. In this paper, the track condition monitoring based on the bogie and car body acceleration measurements is presented. The track alignment information which can be derived from the bogie and car body sensor is investigated by using a mathematical model and the frequency response analysis. The track irregularities can be estimated by using the bogie and the car body acceleration sensors. The acceleration signals are preprocessing with a DC filter and a low pass filter. After that, the track alignments are obtained by double integrating the signals. Field tests are carried out in Shang Hai metro Line 1 for demonstrating the effectiveness of the proposed track inspection system.     

城市轨道交通工程施工测量中注意问题及应对措施

城市轨道交通包括地铁、轻轨等。现城市轨道交通公司（业主）一般建立了由业主管理、第三方测量的单位，试图阐述城市轨道交通工程中施工测量注意的问题，并对难点、重点及应对措施做了探讨。     

The influence of train properties on railway ground vibrations

This paper uses a sensitivity analysis to quantify the dominant train properties (mass and spacing of wheels and bogies) that contribute to ground-borne vibration generation, with the aim of reducing the complexity of train–track numerical models. This research is significant because ground-borne vibration from railways is a growing problem, particularly in urban areas. Despite this fact, attempting to predict vibration levels is complex because there are many variables that contribute to the overall dynamic response. Therefore, a deterministic approach is commonly used, that ignores many of these variables. Thus, this paper identifies the variables that can be ignored, while highlighting those that are highly influential on vibration generation. For this purpose, a previously validated 2.5D finite elements-boundary elements approach is used to simulate dynamic train–track interaction. It is computed many times for a variety of modelling variables to investigate the effect of each on the ground-borne vibration levels in the far field. It is found that increases in unsprung mass of the train causes a large increase in vibration levels. Furthermore, changes in wheel/bogie spacing and semi-sprung mass are found to have a minimal effect on vibration generation.     

风机转子轴心轨迹的经验模态分解滤波与提纯

介绍了风机转子轴心轨迹的经验模态分解及滤波原理与提纯。采用该方法进行滤波提高了轴心轨迹表述的清晰性,有利于实际风机的故障诊断。     

Development of track condition assessment model based on visual inspection

Inspection and evaluation of railway track conditions are usually accomplished by analysis of geometric data obtained from track recording cars. Although most geometric deviations can be recorded by these cars, track structural defects cannot be identified during automated inspections and the causes of track problems cannot be fully recognised. This limitation makes the efficiency of current maintenance approaches questionable. This research proposes a new method of track evaluation based on the observation of track structural defects. Dominant observable structural distresses were studied and a methodology was proposed to translate structural problems into a meaningful numerical rating. The contribution of a track structural defect to track quality was investigated and a track structural quality index model was developed. This index is a function of the severity and density of distress types. To examine the practicability and applicability of the new index, a practical use of the model is presented.