船用空压机冷却系统结垢现象的探索及防治措施

随着大型船舶的不断涌现,空压机作为船舶上使用的一种辅机,在船舶操纵控制和自动化方面的地位和作用愈显重要.为保证空压机长期稳定高效地运行,必须对其冷却系统内存在的结垢现象加以足够的重视.文章主要针对此结垢现象,分析了形成的原因及可能造成的危害,并提出了一系列防治措施.     

汽车空调系统工作原理及故障诊断

作为汽车的重要组成部分,空调系统一直都在汽车中扮演着重要角色.驾驶员可以借助空调系统,对车内环境(如温湿度等)进行调节,既可提高车内人员舒适度,还可消除附着在挡风玻璃的雾气,避免影响驾驶员的视线.但是经过长时间使用以后,汽车空调系统不可避免地会出现各种问题.文章首先对空调系统的运行原理进行了简单描述,然后分别介绍了空调...     

重视空气滤清器的安装位置

通过对由于空气滤清器安装位置不当造成发动机的充气效率ηv降低的分析,提出妥当安装空气滤清器的建议。     

某特种船空调系统设计

本文详细介绍了某特种船空调系统的组成、功能、布置等的设计。     

A model to identify airport hubs and their importance to tourism in Brazil

Air transportation in Brazil has been recently liberalized and one of the consequences of this process is the concentration of flights in a few hubs. During the years 2006-2007 two fatal accidents created unprecedented chaos in both land and air sides of the system with harmful consequences to tourism in Brazil. The consequences were more airport congestion and many episodes of flight delays and cancellations that lasted for several months. We argue that, among other factors, this state of blackout was a result of the increase in the degree of concentration in few airports, particularly Congonhas (in São Paulo) and Brasília. Using data obtained from a survey with Brazilian experts, a comparison was made with two existing methods (the one used by the US Federal Aviation Administration and the usual Herfindahl-Hirschman method) in order to calculate the number of hubs in Brazil. Due to the huge discrepancy obtained between data from the survey and the other two methods considered, a new mathematical method based on the Herfindahl-Hirschman Index was proposed to identify the number of hubs in a given network. Drawing from the examples of what happened to tourist destinations during and after the air transport crisis in Brazil, the article concludes discussing the need for a more accurate tool to identify and to monitor the concentration of flights at the Brazilian air transportation network and its importance to tourism.     

铁道车辆空气弹簧垂向动态特性分析方法的研究

应用空气动力学、工程热力学理论,推导空气弹簧垂向动态特性分析的数学模型,经过试验验证模型的正确性。分析装有固定节流阀空气弹簧对正弦激扰的减振性能。通过多种方案节流孔直径的空气弹簧对于不同幅值激扰的振动位移传输率的分析,确定了TY550型空气弹簧固定节流阀对于不同幅值激扰的最优取值范围,得出固定节流阀节流孔直径选取的原则是对于小幅值激扰应选取较小值,而大幅值激扰则应选稍大一些的值。     

FYJK-1型微机风源监测与控制系统的几点改进

本文分析了FYJK-1型微机风源监测与控制系统存在的问题，并提出了解决方法。     

论我国城市公交电动客车的开发

迈入新世纪,防治城市空气污染的紧迫重任摆在国人面前。据环保部门统计:城市空气污染源的60%以上来自交通运输车辆的废气排放。本文就开发我国零污染的城市公交电动客车作探讨性的论述。     

测定汽车滑行阻力系数的方法

从汽车滑行运动微分方程入手，经过积分推导出滚动阻力系数和空气阻力系数与滑行初速度、滑行总时间和滑行总距离之间的关系，用滑行过程中3个瞬时点的记录参数组成方程组，再用MATLAB求方程组的数值解，即可求出汽车的滚动阻力系数和空气阻力系数。本方法只需一次滑行试验，既方便易行，又比较准确。     

汽车轮胎气压电子实时监测系统

轮胎气压不足,将增大轮胎的弯曲变形,加快轮胎的磨损,增大车轮的滚动摩擦阻力,从而导致油耗显著增加,特别是当汽车高速行驶时,更会削弱轮胎的承载能力,导致轮胎破裂漏气。以北美市场及德国BERU公司的产品为例,介绍了轮胎压力电子实时监测系统的技术和市场方面的最新发展趋势。