农用车辆驱动系统普通V带传动概率优化设计

普通V带传动是农业机械中应用极为普遍的一种传动形式。在常规设计中,一般根据给定的已知行条件如功率、转速、中心距以及其工作环境等参数来确定。提出了一种新的设计方法,运用可靠性理论与最优化设计技术,在保证预期可靠度及其他随机约束概率的条件下,建立了农用车辆驱动系统普通V带的概率优化设计数学模型,并通过V带传动实例计算分析,得到了比常规设计更为合理的设计结果。     

Saturation characteristics of low voltage ionization chamber filled with argon or xenon

Argon and xenon are both attractive working gas for low voltage ionization chamber (LVIC), which is a promising candidate for ITER X-ray detectors. In this work, the performances of Ar-filling LVIC (Ar-LVIC) and Xe-filling LVIC (Xe-LVIC) as well as the impacts of operation parameters were investigated. Saturation curves of Ar-LVIC and Xe-LVIC with pressure from 0.4 to 1.2 bar were measured with a tungsten X-ray source. The minimum voltage of saturation region (${V}_{{\rm{\min }}}$) of Ar-LVIC and Xe-LVIC, the relationship between ${V}_{{\rm{\min }}}$ and saturation current, the ideal operating voltage in ITER and impacts of pressure on saturation current were studied. It was found that Ar-LVIC had smaller ${V}_{{\rm{\min }}}$ and saturation currents which decreased with the drop of pressure from 1.2 to 0.4 bar; Xe-LVIC had larger ${V}_{{\rm{\min }}}$ and saturation currents which did not obviously decrease with the same pressure drop. It is envisaged that ITER can take advantage of the larger saturation current and lower pressure of Xe-LVIC in the non-nuclear operation phase, and flexibility of pressure and low sensitivity to neutron/gamma radiation of Ar-LVIC in the nuclear operation phase.     

基于汽车CAN总线概述及其故障检测方法探讨

汽车CAN数据总线具有信息共享,减少导线数量,减轻配线线束的重量,控制单元插脚最小化,提高可靠性和可维修性等优点。针对装有车载网络系统的车辆在行驶过程中,车载网络系统出现故障时,造成接收信息的电控单元将无法正常工作,从而为汽车故障诊断带来困难等特点。通过对CAN总线系统组成、CAN总线的特点、数据总线应用、数据总线传输原理、数据传输过程等内容进行逐一研究,及对CAN总线故障现象特征分析,从而总结出汽车CAN总线技术故障类型主要有三种:一是电源系统引起的故障;二是多路信息传输系统链路故障;三是多路信息传输系统节点故障。并通过故障机理和故障实例分析,给出了相应的系统故障检测步骤以及所采用的故障检测设备与检修方法等。