计算脉动风作用下拉索反应的一种新方法

提出了Ansys基于一点加速度时程分析方法,并用此方法对滨州黄河大桥最长的一根斜拉索N26进行脉动风荷载作用下的动力计算,包括计算原理和建模过程,并与实测结果进行对比。     

流水槽对客车风阻影响的仿真及试验

基于某中型发动机后置客车,建立整车的仿真模型分析流水槽导致整车风阻增加的流动机理,在此基础上提出圆弧型流水槽结构,并通过仿真和整车等速油耗试验进行验证。     

斜拉索涡激振动的被动自吸吹气流动控制

圆形斜拉索长细比大、阻尼及刚度小，因而其经常发生风致振动，尤其是涡激振动。涡激振动是一种限幅振动，其发生风速较低，因而斜拉索经常发生涡激振动现象，为此提出一种被动自吸吹气流动控制措施来抑制斜拉索涡激振动。通过节段模型气弹试验得到，被动吸吹气控制方法在套环间距适当下使得斜拉索涡激振动区间变窄，甚至可以完全抑制其发生涡激振动。通过分析斜拉索节段模型表面压力分布，得到被动自吸吹气能大幅度降低压力脉动值和脉动风荷载；且模型背风面的平均压力值的平台区也有所提升，表明平均阻力也有所减小。频谱分析表明：此控制方法改变了旋涡脱落模式及脱落强度。最后由尾流速度剖面可得，被动吸吹气流动控制方法缩小了模型尾流区宽度，尾流中的速度脉动也极大降低。折算风速为5.99时，对尾流速度时程做频谱分析可得，吸吹气控制方法能抑制住无控圆柱模型尾流中周期性交替脱落的旋涡。套环控制方法应用于三维柔性索性索模型上，能极大地降低柔性斜拉索的前三阶涡激振动幅值，同时发现套环间距越小，控制效果越强。     

天然气发动机技术及其在大客车上的应用

简要介绍了天然气发动机的发展历程及工作原理.重点阐述天然气发动机技术在大客车上的应用及各总成的功能与布置.     

Effect of wind speed variation on the dynamics of a high-speed train

The severe shaking due to wind speed variation in high-speed trains has a negative impact on driving safety and riding comfort. It is difficult to solve this problem by directly applying civil engineering technology because of the actual conditions. Therefore, set up a reasonable train operation plan considering the wind speed variation under strong winds is very important. In this study, a multi-body simulation model of a CRH2 high-speed rail vehicle is constructed, and the overturning coefficient is set as the safety limit, we established a crosswind model on the basis of measured wind speed curves and investigated the effect of the rate of wind speed changes, the duration of maximum wind speed and the variation of wind speed in different amplitude on the dynamics of the high-speed train. Considering the most critical wind speed variation conditions, the characteristic wind curve is obtained, which can be used as a reference to set up a reasonable train operation scheme considering the wind speed variation.     

基于二极管箝位级联拓扑变流器的直驱风电用变流技术

直接驱动型风力发电系统需要全功率变流器作为与电网的接口，多电平变流器的应用得到了广泛关注。二极管箝位五电平级联H桥拓扑，结合了二极管箝位型多电平和级联H桥多电平的优势，只需较少的箝位二极管和独立直流电源，即可进一步提高输出电压等级；使用移相变压器和12脉波整流器作为输入电路.可以方便地应用在使用多相永磁同步发电机的直驱风电系统中。基于拓扑提出了消谐波SPWM和载波相移SPWM相结合的调制方法，能够方便地对二极管箝位级联拓扑进行控制，可以进一步提高等效载波频率，减小器件损耗和滤波器体积。仿真和实验结果证实了所采用的拓扑及其控制方法的有效性。     

自然肿瘤红细胞花环试验的建立及临床应用

作者通过对红细胞在无补体存在情况下能直接与Ｓ１８０发生免疫粘附的机理及实验方法进行了研究，从而建立了自然肿瘤红细胞花环试验（ＮＴＥＲＴ）。通过临床应用，该方法具有简便、快速、实用、准确、易于观察等优点，有辅助诊断恶性肿瘤以及其与良性肿瘤的鉴别等作用，适宜于各级医疗单位和科研单位应用。     

DSA250型受电弓振动特性仿真与测试

以DSA250型受电弓为例,分别进行质量块模型计算、有限元模型仿真和实验测试,求得其固有频率,并把3种方法得出的结果加以比较。     

Wind-induced mesoscale circulation off the Ebro delta, NW Mediterranean: a numerical study

It is well known that the general circulation on the Catalan continental slope is dominated by a quasi-permanent southwestward geostrophic jet associated to the so-called Catalan front [Millot, C., 1987. Circulation in the western Mediterranean sea. Oceanol Acta 10, 143–149; Font, J., Salat, J., Tintoré, J., 1988. Permanent features of the circulation in the Catalan Sea. Oceanol. Acta 9, 51–57]. On the continental shelf, however, the flow is modified by the action of friction which enhances also other nonlinear interactions. Several authors have hypothesized that the shelf circulation is anticyclonic north of the Ebro delta [Salat, J., Manriquez, M., Cruzado, A., 1978. Hidrografia del golfo de Sant Jordi. Campaña Delta (Abril 1970). Investigación Pesquera 42 (2), 255–272; Ballester, A., Castellví, J., 1980. Estudio hidrográfico y biológico de las plataformas continentales españolas: I. Efecto de los efluentes de una planta de energía nuclear en el Golfo de San Jorge (Febrero 1975–Octubre 1976). Informes Técnicos del Instituto de Investigaciones Pesqueras 76, 70 pp.]. A quasi-3D finite element code based on the shallow-water equations has been used to explore the effect of several mechanisms which might be responsible for such a local circulation pattern, and in particular of wind. The obtained numerical results suggest that the basic anticyclonic structure of the mean flow is controlled by the bathymetry and that the clockwise-rotating mean flow pattern is not a permanent circulation feature. It is seen that the characteristic local wind stress fields—computed through interpolation of the records of a local network of meteo stations—may ‘enhance' or ‘delete' the anticyclonic gyre depending on the sign of their relative vorticity. According to the analysis of a 2-yr record of local wind data, the net contribution of wind events with a duration longer than 24 h is to reinforce the anticyclonic circulation (over 70% of these wind fields supply negative relative vorticity to the study area).     

提高广州珠江黄埔大桥悬索桥颤振临界风速的研究

改善抗风稳定性能是大跨度悬索桥设计和建造中的一个重要课题。由初步设计与施工图设计阶段模型试验的结果对比可知,调整结构的气动外形和整体刚度,能改善广州珠江黄埔大桥悬索桥的颤振稳定性能。