关于一种新模型对软件总体可靠度的估计

本文在对文[4]中软件可靠度的估计进行研究的基础上,提出了软件总体可靠性的一个新模型,对软件总体的可靠度进行了讨论,利用点估计方法,得到软件可靠度的点估计值,证明了软件总体失效率λ估计解的唯一性,并对缺陷数进行了估计,从而给出了新模型下软体总体可靠性的估计.     

Weibull分布场合无失效数据的可靠性验证试验

对于Weibull分布的无失效数据问题,利用Bayes方法给出了产品寿命服从Weibull分布,形状参数的先验分布为U(0,1),尺度参数为1,假定产品的可靠性指标达到某个给定的值的情况下,无失效数据的可靠性验证试验,并利用相同的分析方法给出形状参数的Bayes估计.     

Assessing the reliability of a nanocomponent using nanocrack growth

In nanoscience and nanotechnology, much attention has been given to the dual problem of designing nanocomponents with novel physical properties and how such nanocomponents can be fabricated. Receiving less attention has been the question of the nanocomponent's reliability; how does a nanocomponent fail and how long does a nanocomponent survive under typical operating conditions? High reliability is necessary to guarantee the advancement and utilization of nanocomponents due to the fact that they account for a high proportion of costs of newly designed nanosystems as well as multiscale systems. A nanocomponent is a component that is made of atoms, and its reliability is determined by these atoms. There are situations where it is hard or impossible to extract information from a nanocomponent about its relationship to its atoms. In this article, we assess the nanocomponent's reliability by using its physical properties. Specifically, it is known that nanocrack growth involves considerable statistical variability and such variability should be accounted for assessing growth. In this paper, we first provide a stochastic nanocrack growth model and then evaluate the reliability of a nanocomponent based on this model. Various properties of this model are obtained. We also evaluate the reliability of a nanocomponent under different assumptions on our proposed growth model. This paper is a modification of the extensive literature on modeling fatigue cracks in materials on a larger scale, applied to nanoscale where growth is not a function of cumulative stress on the component but related to the time to first exceedance of a threshold. Copyright © 2013 John Wiley & Sons, Ltd.     

Bayesian inference for Pr (Y

《Applied Mathematical Modelling》2014,38(5-6):1698-1709

风电场可靠性模型及其应用

考虑了风速分布的季节性差异和风速的随机变化的影响、风电机组的实际功率特性、风电场尾流效应以及风电机组故障状况,建立了风电场可靠性模型.根据某海上风电场实测数据进行数值仿真实验,结果验证了模型的正确性和有效性.模型为进一步研究大规模风电并网以及风电场功率预测等问题打下了基础.     

Optimal corrective maintenance contract planning for aging multi‐state system

This paper considers an aging multi‐state system, where the system failure rate varies with time. After any failure, maintenance is performed by an external repair team. Repair rate and cost of each repair are determined by a corresponding corrective maintenance contract with a repair team. The service market can provide different kinds of maintenance contracts to the system owner, which also can be changed after each specified time period. The owner of the system would like to determine a series of repair contracts during the system life cycle in order to minimize the total expected cost while satisfying the system availability. Operating cost, repair cost and penalty cost for system failures should be taken into account. The paper proposes a method for determining such optimal series of maintenance contracts. The method is based on the piecewise constant approximation for an increasing failure rate function in order to assess lower and upper bounds of the total expected cost and system availability by using Markov models. The genetic algorithm is used as the optimization technique. Numerical example is presented to illustrate the approach. Copyright © 2009 John Wiley & Sons, Ltd.     

基于改进自适应混沌控制的逆可靠度分析方法

自适应混沌控制方法是一种高效、稳健的逆可靠度分析方法,但在求解强非线性凹功能函数时,计算效率仍然有待提高,且可能会陷入局部最优.通过对混沌控制因子更新策略进行改进,提出了基于改进自适应混沌控制的逆可靠度分析方法.数值算例分析表明:该方法能够有效地改善混沌控制因子自适应选取时的合理性,具有更好的收敛性和更高的计算效率,为结构可靠度分析和可靠度优化问题提供了更加高效、稳健的求解途径.     

(5-氨基-[1,3,4]噻二唑-2-基)-丙酸乙酯的合成工艺改进

以丁二酸酐为起始原料,经醇解和酰化反应制得丁二酸单乙酯酰氯(3);3经甲烷磺酸催化与氨基硫脲环合合成了重要药物中间体——(5-氨基-[1,3,4]噻二唑-2-基)-丙酸乙酯,其结构经~1H NMR,IR和MS确证。运用正交试验对环合反应条件进行优化。最优反应条件为:3 132 mmol,n(氨基硫脲)∶n(3)∶n(甲烷磺酸)=1∶3∶3,于110℃反应3 h,总收率51.3%。     

富马酸丙酚替诺福韦合成工艺改进

对富马酸丙酚替诺福韦的合成工艺进行了改进,以干燥的替诺福韦为起始原料,与亚磷酸三苯酯反应得到(R)-9-(2-(苯基磷酰基甲氧基)丙基)腺嘌呤（3）; 3被氯化亚砜氯代得(R)-9-(2-(((苯基)(氯代)(磷酰基)甲氧基)丙基)腺嘌呤（4）; 4与L-丙氨酸异丙酯盐酸盐缩合得9-((R)-2-(((S)-((1-(异丙氧基羰基)乙基)氨基)苯氧基磷酰基)甲氧基)丙基)腺嘌呤（5）; 5经析晶纯化得9-((R)-2-(((S)-（((S)-1-(异丙氧基羰基)乙基)氨基)苯氧基磷酰基)甲氧基)丙基)腺嘌呤（丙酚替诺福韦,6）; 6与富马酸成盐得富马酸丙酚替诺福韦,其结构经¹H NMR, ¹³C NMR, MS(ESI),元素分析和XRD确证。按改进工艺进行公斤级规模放大,产品总收率达到32.2%,化学纯度99.92%,非对映异构体纯度99.99%。     

Polyaniline/Platinum Composite Cathode Catalysts Towards Durable Polymer Electrolyte Membrane Fuel Cells

Polymer stabilization proved to be a promising approach to increase the catalytic performance of common platinum/carbon based cathode catalysts (Pt/C) used in polymer electrolyte membrane fuel cells (PEMFCs). Platinum and polyaniline composite catalysts (Pt/C/PANI) were prepared by combining chemical polymerization reactions with anion exchange reactions. Electrochemical ex-situ characterizations of the decorated Pt/C/PANI catalysts show high catalytic activity toward the oxygen reduction reaction (ORR) and, more importantly, a significant enhanced durability compared to the undecorated Pt/C catalyst. Transmission electron microscopy (TEM) investigations reveal structural benefits of Pt/C/PANI for ORR catalysis. All studies confirm high potential of Pt/C/PANI for practical fuel cell application.