基于RBD与FTA的航天器太阳翼可靠性分析

太阳翼对航天器的在轨运行品质有重要影响。该文基于东方红3号卫星平台,对系统部件的可靠性属性进行了分类,利用可靠性框图(RBD)给出了在确定载荷与随机载荷情况下的可靠度计算公式。应用故障树分析法(FTA)研究了太阳翼系统的可靠性问题。分析结果表明:铰链是影响太阳翼可靠性的最主要部件;空间温度、材料在空间中的特性是影响太阳翼可靠性的最主要因素。添置冗余、采用新型材料与优化受载结构等方法可以提高太阳翼的可靠度。     

Comparison of an SMS text messaging and phone reminder to improve attendance at a health promotion center： A randomized controlled trial

Objective： To compare the efficacy of a short messaging service （SMS） text messaging and phone reminder to improve attendance rates at a health promotion center. Methods： A total of 1 859 participants who had scheduled appointments in the health promotion center of our hospital from April 2007 to May 2007 were enrolled in the study and randomly assigned into 3 groups： control （no reminder） group, SMS text messaging reminder group and telephone reminder group. Attendance rates and costs of interventions were collected. Results： A total of 1848 participants were eligible for analysis. Attendance rates of control, SMS and telephone groups were 80.5%, 87.5% and 88.3%, respectively. The attendance rates were significantly higher in SMS and telephone groups than that in the control group, with odds ratio 1.698, 95% confidence interval 1.224 to 2.316, P=0.001 in the SMS group, and odds ratio 1.829, 95% confidence interval 1.333 to 2.509, P〈0.001 in the telephone group. However, there was no difference between the SMS group and the telephone group （P=0.670）. The cost effectiveness analysis showed that the cost per attendance for the SMS group （0.31 Yuan） was significantly lower than that for the telephone group （0.48 Yuan）. Conclusion： SMS and telephone are effective reminders for improving attendance rate at a health promotion center. SMS reminder may be more cost-effective compared with the telephone reminder.     

Influence of DC Supply Systems on Unplanned Reactor Trips in Nuclear Power Plants

IntroductionMany factors influence the economics ofnuclear power plants.Unplanned reactor trips arethe most important factors,so it has beeninvestigated from various aspects because oftheirinfluence on the operating capacity factor inNuclear Power Plants ( NPPs ) .Operationalexperience has shown thatsome components in theNPPs are so importantthattheir failure may causethe entire plantto shutdown.Such shutdowns haveoften occurred in the pastin the NPPs.So,nuclearpowerplantauthorities have…     

中韩自由贸易协定与世界生物资源战争

2014年11月10日至11日于北京举行的APEC(Asia Pacific Economic Cooperation)峰会上,国家主席习近平与韩国总统朴槿惠就深化中韩战略合作伙伴关系达成广泛共识,双方决定加快中韩自由贸易区协定谈判,并宣布了中韩自由贸易区协定实质性谈判已圆满完成。中国之所以主动组织、推进此次会议,主要原因有两个。从外部来看,中韩自由贸易协定(FTA)的签署有利于稳固两国在东北亚及东南亚地区的政治、经济地位,并与竞争对手日本形成抗衡力量。从内部来看,通过与韩国的合作,还能够缓解中国现有的"三农问题"。随着未来中国农产品的大量对外出口,虽会促使我国农民收入得到增长,但也会给中国的生物资源带来潜在的威胁。特别是近年来在发达国家之间悄无声息展开的"生物遗传资源战争"中,中国将会受到不小的冲击。     

地铁变阻制动系统FTA分析

运用系统可靠性工程设计理论，对城市地下铁路变阻制动系统进行可靠性分析，寻找导致故障的模式，判断潜在的故障，以利于改进设计方法和制订维修方案。     

故障树和人工神经网络在可靠性再分配中的应用

在产品可靠性设计过程中,通常情况下,可靠性指标的分配并不是一次可以完成的,不同的设计阶段有不同的可靠性分配方法。随着设计过程的深入,初步分配的结果可能会存在不合理的情况,所以在设计阶段中后期,还需要对可靠性指标进行再次分配。在进行指标分配之前,用一定的算法将所有最小割集进行筛选,再将筛选出的需要分配的最小割集利用人工神经网络进行指标分配,最终目标是将可靠性指标分配到故障树的最小割集或基本事件上。通过分配前初始可靠性与分配后的可靠性对比,可以找出产品设计中的薄弱环节进而改进设计,并在一定程度上检验了FMECA(failure mode,effects and criticism analysis,故障模式、影响及危害性分析)的结果。     

基于故障树分析的鱼雷可靠性评定方法

针对鱼雷系统特点,建立了基于故障树分析的系统可靠性评定模型,该模型除了可克服常规金字塔式可靠性评定方法所存在的缺陷外,还可更直观、直接地反映系统功能结构及故障状态,适用于含重复单元、非串联或非并联的各种复杂系统。重点研究了故障树分析的贝叶斯近似评定方法,并对鱼雷系统进行了可靠性评定实例分析,结果表面所提出的基于故障树可靠性评定方法较传统可靠性评定方法更方便、更直观。     

ZQ—86牵引电动机FTA分析

运用系统可靠性工程设计理论 ,对地铁的ZQ— 86牵引电动机进行系统可靠性分析 ,寻找导致故障的模式 ,判断潜在的故障 ,以利于改进设计方法和制订维修方案     

Interval Fault Tree Analysis of Excavator VariableFrequency Speed Control System

In consideration of the uncertainty of basic events failure rate and lack of probability statistical information in fault tree analysis（ FTA） of excavator variable-frequency speed control system, the interval theory was employed and combined with conventional FTA method. The basic events failure probabilities were described by interval numbers,and the interval operators of logical gates in FTA were deduced based on interval theory. Finally,the reliability assessment of excavator variable-frequency speed control system was done by interval FTA method. The result shows that the interval FTA method is suitable for the complex system with insufficient failure data.     

日语终助词“カナ”的语用功能

日语终助词"カナ"的某些使用场合,反映出其语用方面的功能;从面子保全理论来分析,带有"间接指令型‘カナ’"的表达作为间接言语行为,是通过"不实施面子威胁行为"这一补救策略来体现其礼貌性的;"间接指令型‘カナ’"在具有较高礼貌性的同时,伴随着较高的交际失败风险。为降低风险,说话人有时需一定程度地牺牲礼貌性。