垃圾转运车上翻式后门装置

介绍了某垃圾转运车的后门装置,该后门装置在液压缸的驱动下,可上翻至垃圾箱的顶部,从而方便垃圾从箱体后门尾部装入。     

How well a single-track linear model captures the lateral dynamics of long combination vehicles

ABSTRACT

The effect of centre-of-gravity heights on the high-speed performance measures of long combination vehicles including truck with double centre-axle trailers, Nordic, and A-double combination vehicles is investigated. The high fidelity three-dimensional models, used in this research, are validated against physical test data. These models are often accurate in terms of the actual dynamic behaviours of the vehicle. On the other hand, the simple yaw-plane single-track models with linear tires require less number of vehicle parameters. In this paper, it is investigated how accurate the estimations of performance measures are at high forward speeds by such single-track linear (STL) models. The influence of load height is especially studied. The high-speed performance-based standard or PBS measures considered are rearward amplifications of both lateral acceleration and yaw velocity; lateral load transfer; yaw damping and high-speed transient offtracking. The results show that tire relaxation has a large effect and it is rather easy to add to an STL model, so it is assumed to be modelled in STL. With realistically high payload and a required accuracy of PBS measures of approximately 10%, only the accuracy of rearward amplification of yaw velocity calculated by the frequency response is fulfilled by the STL. With low payload, the same statement is valid, but with around 5% in required accuracy. The roll dynamics effects are more important than the tire non-linearities.     

TRANSVAGINAL COLOR DOPPLER STUDY OF UTEROPLACENTAL CIRCULATION IN NORMAL EARLY PREGNANCY

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船舶应急电系统受控的逻辑关系

为加强轮机人员对电力系统知识的掌握,根据现代大型集装箱船电力系统的特点,详细介绍了船舶应急电系统受控的逻辑关系,特别指出联络开关的意义和作用,可为船舶电站设计、轮机设备维护管理及故障分析提供指导。     

交直传动相控电力机车过电压保护参数的合理匹配

交直电力机车分别在牵引绕组和整流器元件设置阻容吸收电路以降低操作过电压和换流过电压，探讨了二者在整流器工作过程中的相互作用与影响，当参数选配不当，会造成二极管关断损坏和晶闸管开通损坏，阻容器件也会出现烧损故障；指出当前运用机车普遍存在绕组阻容参数失配情况，以致晶闸管故障率高，阻容器件烧损严重，提出满足各种机车过压保护的优化调整方案。     

某山区公路滑坡分析及治理策略分析

针对山区公路特殊的地质条件及复杂结构,容易引起公路滑坡的问题。以某一山地高速公路为实例,采用传递系数法和FLAC 3D方法对天然状态(自重条件)和饱和状态(自重状态+暴雨状态)下的公路滑坡进行稳定性分析,并提出滑坡治理方案。研究表明:传递系数法和FLAC 3D数值模拟法下获得天然状态下滑坡的稳定系数值均在1.06附近,滑坡处于基本稳定状态;饱和状态下的滑坡稳定系数值在0.92附近,处于不稳定状态。针对饱和状态的不稳定性,提出采用削坡法和布设抗滑桩法两种防治方案。对两种滑坡质量方案进行模拟分析表明:削坡法经济有效,但易引起上级滑坡,造成二次灾害,布设抗滑桩法花费高,工程量大,对滑坡稳定性效果显著,实际施工中根据山体高速公路的具体路面情况选择合适的抗滑桩参数。     

牵引模式对C0-C0架悬式机车粘着性能的影响

分析了牵引模式对C0-C0架悬式机车粘着性能的影响.通过对牵引装置不同布置方式进行比较,指出机车的轴重转移量以车体中央截面成对称分布,对应轮对上的粘着质量利用率之和为定值;并提出牵引点高度对机车粘着性能影响较大,而牵引装置布置方式对其影响较小,机车设计时需根据悬挂特性选择合适的牵引点高度.     

Theoretical and experimental excitation force spectra for railway-induced ground vibration: vehicle–track–soil interaction,irregularities and soil measurements

Excitation force spectra are necessary for a realistic prediction of railway-induced ground vibration. The excitation forces cause the ground vibration and they are themselves a result of irregularities passed by the train. The methods of the related analyses – the wavenumber integration for the wave propagation in homogeneous or layered soils, the combined finite-element boundary-element method for the vehicle–track–soil interaction – have already been presented and are the base for the advanced topic of this contribution. This contribution determines excitation force spectra of railway traffic by two completely different methods. The forward analysis starts with vehicle, track and soil irregularities, which are taken from literature and axle-box measurements, calculates the vehicle–track interaction and gets theoretical force spectra as the result. The second method is a backward analysis from the measured ground vibration of railway traffic. A calculated or measured transfer function of the soil is used to determine the excitation force spectrum of the train. A number of measurements of different soils and different trains with different speeds are analysed in that way. Forward and backward analysis yield the same approximate force spectra with values around 1 kN for each axle and third of octave.     

垃圾转运车后门液压系统故障分析

针对在实际生产过程中出现的垃圾转运车后门不能举升和下降的故障现象,通过对液压系统原理图的分析和借助适当的检测工具,按照由简单到复杂的原则,逐一排查可能引起故障的原因,使故障得以快速解决,并提供了一种对故障原因进行分析的思路。     

Experimental study of the airside performance for interrupted fin-and-tube heat exchanger with hydrophilic coating under dehumidifying conditions

The airside heat transfer and friction characteristics of seven interrupted fin-and-tube heat exchangers with hydrophilic coating under dehumidifying conditions are experimented. The effects of number of tube rows, fin pitch and inlet relative humidity on airside performance are analyzed. The test results show that the influence of fin pitch on the friction characteristic under dehumidifying conditions is similar to that under dry surface, and the friction factors decrease slightly with the increase of number of tube rows. The heat transfer performance decreases as fin pitch and number of tube rows increases. The heat transfer performance and the friction characteristic are independent of inlet relative humidity. Based on the test results, heat transfer and friction correlations in terms of the Colburn j factor and Fanning f factor, are proposed to describe the airside performance of the interrupted fin geometry with hydrophilic coating under dehumidifying conditions. The correlation of the Colburn j factor gives a mean deviation of 9.7%, while the correlation of the Fanning f factor shows a mean deviation of 7.3%.