汽油机颗粒物捕捉器(GPF)的碳载模型计算介绍

汽油机颗粒物捕捉器(GPF)能有效地捕集汽车排气中的颗粒物,其过滤效果可接近90%。EMS通过对车辆运行过程中碳颗粒(soot)的生成速率以及系统控制再生过程的碳颗粒(soot)的燃烧速率积分计算,进而计算出GPF中累积的颗粒物的质量。因此对碳颗粒的累积质量及再生质量的计算极其重要。     

新能源汽车技术服务技能竞赛与职业教育改革探索研究

新能源汽车的出现,既体现了社会的可持续发展理念,又体现了汽车领域对技术的突破与创新,使新型出行方式逐渐在生活中被渗透。然而,与新能源汽车的销路大增不相匹配的是,该类型汽车的配套服务还非常滞后,尤其是涉及到技术维修的配套服务。可喜的是,已有众多职业院校看到了这一领域的职业需求,并开设起与之对应的技术专业,着力于向社会输送相关人才。这在很大限度上推动了新兴领域的发展,却也因该类专业的教育发展不成熟而存在诸多桎梏。这样的背景下,技能竞赛逐渐被人们重视起来,成为被探索的新的促进职业教育改革的途径。     

Effect of vehicle vibration environment of high-speed train on dynamic performance of axle box bearing

In this study, we developed a comprehensive three-dimensional vehicle–track coupled dynamics model considering the traction drive system and axle box bearing. In this model, dynamic interactions between the axle box bearing and other components, such as the wheelset and bogie frame, are considered based on a detailed analysis of the structural properties and working mechanism of the axle box bearing. A few complicated dynamic excitations, such as the time-varying mesh stiffness of gears, time-varying stiffness of bearing, bearing gaps and track irregularities, are considered. Then, the dynamic responses of the vehicle–track system are demonstrated via numerical simulations based on the established dynamics model. The results indicate that the traction drive system and track irregularities can significantly influence the dynamic interactions of the axle box bearing. The necessity of considering the excitation caused by gear meshing and track irregularities when assessing the dynamic performance of the axle box bearing is demonstrated.     

铁路重载运输效益评价研究

大力发展铁路重载运输,可以使铁路繁忙干线的运输能力迅速提高,使我国能源结构中处于主导地位的煤炭的供求紧张关系将得到有效缓解,占铁路货运主导地位的大宗货物运输也将迅猛增长.铁路重载运输,将提高整个社会的经济效益和社会效益,促进国民经济的可持续发展.     

高温作用对混凝土破坏准则的影响

借助连续介质力学理论,将损伤变量D引入强度理论,从理论上建立了混凝土材料因高温作用的损伤破坏准则,以反映材料内部状态的改变对混凝土材料强度的影响.计算值与文献试验值的对比结果证实了所提出的损伤破坏准则的合理性,同时也表明双轴强度极限线是逐渐萎缩的.     

A new data acquisition and processing system for profiling sonar

A multi-beam chirp sonar based on IP connections and DSP processing nodes was proposed and designed to provide an expandable system with high-speed processing and mass-storage of real-time signals for multi-beam profiling sonar. The system was designed for seabed petroleum pipeline detection and orientation, and can receive echo signals and process the data in real time, refreshing the display 10 times per second. Every node of the chirp sonar connects with data processing nodes through TCP/IP. Merely by adding nodes, the system＇s processing ability can be increased proportionately without changing the software. System debugging and experimental testing proved the system to be practical and stable. This design provides a new method for high speed active sonar.     

泡沫改良富水砂层工程性质的实验研究

土压平衡盾构穿越复杂地层时,必须采取土体改良措施,目前泡沫改良土体已被广泛应用于盾构施工中.我国地铁施工中所用泡沫剂多为进口产品,国内产品因质量原因采用很少.利用自行研制的泡沫剂开展泡沫对细砂、粗砂土性改良的试验研究表明,泡沫不但能显著降低砂土的渗透系数和剪切强度,而且能大大增强土的压缩性:若加入适量膨润土或粘土,则可获得进一步提高砂土保水性、流动性及进一步降低砂土的渗透系数和剪切强度的效果,这对盾构施工中改良土体工程性质的研究具有重要意义.     

分层教学法在高职汽车检测与维修专业中的价值

随着我国现代社会经济水平的不断提升,各地区的私家车汽车数量逐渐增多,且汽车整体结构愈发复杂,工艺水平不断提升,传统的汽车检测与维修方法已经无法满足其实际需求。基于此种背景,高职汽车检测与维修专业课程内容不断增多,教师需要积极引进不同的教学方法,针对班级中学生情况开展分层教学,以此提高教学效率与教学质量,培养更加优秀的汽车检测与维修专业人才,为我国社会提供优质汽车服务。文章简要分析了分层教学法及其在汽车检测与维修专业中的应用价值,对如何充分发挥分层教学法在汽车检测与维修专业中的应用价值进行深入探究。     

基于支撑伺服组合系统超深基坑安全支护技术研究

为研究城市建筑密集区域深大基坑支护体系受力规律与安全支护技术,采用数值模拟手段对昆明轨道交通4 号线火车北站深大基坑开挖过程中支护体系受力变形规律开展研究,并结合现场监测手段对支撑伺服系统布置与应用效果进行论述分析。研究结果表明: 1)受支撑形式与支撑间距影响,内支撑体系中钢筋混凝土支撑轴力水平要大于钢支撑,支撑轴力呈折线分布,在混凝土支撑施作期间围护结构容易发生较大变形; 2)引入支撑轴力伺服系统,依据数值计算与设计要求,设定正确的轴力控制值,能更好地发挥支撑对围护结构的变形控制作用; 3)工程应用实际表明,支撑轴力伺服系统在深大基坑施工应用中效果良好,采用伺服支撑段围护结构累计水平变形要小于无伺服段,支护效果更为优越。     

A Study on Location of Facilities of Acceptable Gap Control System of the Entrance Ramp on Expressway

The concept of control system of acceptable gap in the entranceramp, the construction of the minimum acceptable gap and the method of determining it are introduced. On the above-mentioned basis and by taking the Chinas reality into consideration, the issues on the design of control system of acceptable gap are approached in this paper.