Multi-Point and Multi-Interval Availabilities for Markov Repairable Systems with History-Dependent Up and Down States

A Markov repairable system with history-dependent up and down states is presented. The state space of the repairable system is divided into three sets, which are up states, down states and changeable states.Using aggregated stochastic processes, we can get the multi-interval availability and multi-point availability for the Markov repairable system. Finally, numerical examples are given to illustrate the obtained results.     

类叶升麻苷通过激活ERK1/2诱导血红素加氧酶-1的表达

目的探讨类叶升麻苷(actesoide)诱导血红素加氧酶-1(HO-1)表达的信号机制。方法类叶升麻苷单独处理体外培养的PC12细胞或运用ERK1/2抑制剂PD98059预处理,提取细胞蛋白,Western blot方法检测pERK1/2和ERK1/2以及HO-1蛋白表达水平。结果与正常对照组相比,类叶升麻苷可以诱导HO-1的表达上调,类叶升麻苷激活ERK1/2,后者激活介导类叶升麻苷诱导HO-1的表达上调,因为PD98059预处理后可以减弱类叶升麻苷引起的HO-1蛋白表达水平降低。结论类叶升麻苷通过激活ERK1/2通路诱导HO-1的表达。     

3 ns RTP电光腔倒空调Q激光器

采用RTP(磷酸钛氧铷)晶体为电光Q开关,利用腔倒空技术,实现LD(半导体激光器)端面抽运Nd:YVO4晶体的1 064 nm调Q激光输出。在不同重复频率及不同抽运功率条件下,激光输出脉冲宽度保持在3.1±0.3 ns。考虑腔倒空过程中净增益为零,给出LD抽运的Nd:YVO4腔倒空激光器的输出脉冲波形方程,并数值求解该理论方程,其理论计算与试验结果相符。     

基于残余力向量法的基桩损伤诊断

根据振动微分方程详细推导了残余力向量的表达式,定义残余力向量的绝对值为结构的损伤指标。通过建立髙桩码头基桩有限元模型,运用残余力向量法对基桩进行损伤诊断数值模拟。数值模拟结果表明:残余力向量作为诊断指标,对结构的损伤较为敏感;只需结构的低阶模态,就可以准确快速地识别出结构的损伤。     

全承载客车正面碰撞吸能器设计与验证

为开发大型全承载客车碰撞吸能器，通过整车正面碰撞有限元仿真分析，确定了吸能器合理的吸能量和压溃力，以压溃力为目标进行吸能器结构参数设计。采用铝合金和DP600钢试制了吸能器样件，通过静态压溃试验对比不同吸能器的压溃力和变形模式，并通过台车碰撞和整车碰撞试验验证吸能器性能。结果表明，铝合金吸能器的压溃变形模式稳定，材料没有撕裂现象，在正面碰撞、偏置碰撞、斜角碰撞等多种碰撞工况下都能产生良好变形，满足整车碰撞安全性的要求。     

An investigation of incident frequency,duration and lanes blockage for determining traffic delay

Traffic delay caused by incidents is closely related to three variables: incident frequency, incident duration, and the number of lanes blocked by an incident that is directly related to the bottleneck capacity. Relatively, incident duration has been more extensively studied than incident frequency and the number of lanes blocked in an incident. In this study, we provide an investigation of the influencing factors for all of these three variables based on an incident data set that was collected in New York City (NYC). The information about the incidents derived from the identification can be used by incident management agencies in NYC for strategic policy decision making and daily incident management and traffic operation. In identifying the influencing factors for incident frequency, a set of models, including Poisson and Negative Binomial regression models and their zero‐inflated models, were considered. An appropriate model was determined based on a model decision‐making tree. The influencing factors for incident duration were identified based on hazard‐based models where Exponential, Weibull, Log‐logistic, and Log‐normal distributions were considered for incident duration. For the number of lanes blocked in an incident, the identification of the influencing factors was based on an Ordered Probit model which can better capture the order inherent in the number of lanes blocked in an incident. As identified in this study, rain is the only factor that significantly influenced incident frequency. For incident duration and the number of lanes blocked in an incident, various factors had significant impact. As concluded in this study, there is a strong need to identify the influencing factors in terms of different types of incidents and the roadways where the incidents occured.     

SS8型机车主电路瞬间接地故障的判断与预防

针对SS8型机车主电路瞬间接地故障,从主电路各设备的结构和机车运行环境、机车检修等方面进行分析,在总结多年工作经验的基础上,提出了主电路瞬间接地的分析判断方法及预防措施,从而有效减少机车主电路瞬间接地故障的发生,保障机车运行安全。     

E-TYPE雕塑

每年夏天的英国古德伍德速度节(GoodwoodFestival of Speed)上,最大的设计亮点是Goodwood House前的雕塑。在过去的十年间,这块艺术宝地一直被英国著名艺术家兼设计师Gerry Judah占领,今年也不例外。这里矗立的是一尊高达28米的捷豹E-Type,以此来庆祝此款跑车诞生50     

欧洲走廊将大规模安装欧洲铁路运输管理系统

欧洲铁路运输管理系统安装会议于2006年4月4日-6日在匈牙利的布达佩斯举行。此次会议由国际铁路联盟主持召开，会议旨在部署欧洲铁路运输管理系统在六大欧洲铁路运输走廊上的安装。此前，欧盟委员会与铁路部门已于3月份通过了一项谅解备忘录。