Assessing the lifetime performance index of products with the exponential distribution under progressively type II right censored samples

In practice, lifetime performance index C_L is used to measure the potential and performance of a process, where L is the lower specification limit. Progressive censoring scheme is quite useful in many practical situations where budget constraints are in place or there is a demand for rapid testing. In this paper, under the assumption of exponential distribution, this study constructs a maximum likelihood estimator (MLE) of C_L based on the progressively type II right censored sample. The MLE of C_L is then utilized to develop the hypothesis testing procedure in the condition of known L. The new testing procedure can be employed by product managers to assess whether the lifetime of products (or items) adheres to the required level in the condition of known L. Finally, we give one example to illustrate the use of the testing algorithmic procedure under given significance level.     

C_(pk)写控制图的研究与应用

控制图与过程能力指数Cp(Cpk)都是用来进行质量分析与处理的重要工具。文 [1]谈及控制图的两类错误 (其概率分别为α、β) ,文 [2 ]讨论了Cpk与α的关系 ,但涉及Cpk与控制图检出力 (1- β)关系的文章却不多。本文以 X控制图为例 ,讨论了α、β、1- β、与Cpk的关系 ,得出了联合应用它们会对工序状态有较好的了解 ,对其适当的调整有助於提高产品质量     

An EM Algorithm for Batch Markovian Arrival Processes and its Comparison to a Simpler Estimation Procedure

Although the concept of Batch Markovian Arrival Processes (BMAPs) has gained widespread use in stochastic modelling of communication systems and other application areas, there are few statistical methods of parameter estimation proposed yet. However, in order to practically use BMAPs for modelling, statistical model fitting from empirical time series is an essential task. The present paper contains a specification of the classical EM algorithm for MAPs and BMAPs as well as a performance comparison to the computationally simpler estimation procedure recently proposed by Breuer and Gilbert. Furthermore, it is shown how to adapt the latter to become an estimator for hidden Markov models.     

SMT工艺设计流程重组研究

电子电路模块制造企业所处的外部环境发生了很大的变化，这就对其工艺设计流程提出了更高的要求。采用业务流程重组理论，对SMT工艺设计流程进行了重组研究，并取得了明显的成效。     

Analytical instrument maintenance and its implications

The various aspects of importance for the maintenance of analytical instruments for process control are discussed. This discussion is based on practical experience in a large industrial chemical company. Emphasis is placed on the organizational aspects and the continuous attention that is needed. Also, the significant role of audits is stressed.     

关于GB8052—87中各CSP方案的LQ值的验证和计算

本文指出了ＧＢ８０５２—８７中ＣＳＰ—１、ＣＳＰ—２和ＣＳＰ—Ｔ方案的ＬＱ值的误差，计算并给出一套精度为１０（－４）的ＬＱ值．     

MULTIVARIATE SURVIVAL DISTRIBUTIONS OF AGE AND RESIDUAL LIFETIME PROCESSES IN NONHOMOGENEOUS POISSON PROCESS

Let{N(t),t≥0} be the nonhomogeneous Poisson process with cumulative intensity parameter Λ(t),{δt,t≥0} the age process,and {yi,t≥0) the residual lifetime process.In the present paper the expressions of n-dimensional survival distribution functions of the processes{δi} and {yi}, and their Lebesgue decompositions are derived.     

成核剂对聚烯烃的结晶和力学性能的影响

本文利用加入各种类型的成核剂的方法得到了不同结晶形态的聚乙烯(PE)和聚丙烯(PP);用偏光显微镜研究了各种成核剂的成核作用和结晶形态;用显微激光分析仪和差动热分析(DSC)研究了各成核剂对结晶和熔融过程的依赖关系,并测定了它们对结晶度的依赖关系,研究了它们对拉伸力学性能的影响。研究结果表明,成核剂可以明显地使晶粒细而均匀,能改变结晶和熔融速率,以适应各种工艺性要求,但对力学性能的影响较小,因此可以根据工艺和使用要求选用不同的成核剂。     

Process splitting of the boundary conditions for the advection–dispersion equation

Rational strategies are considered for the specification of the intermediate boundary condition at an inflow boundary where process splitting (fractional steps) is adopted in solving the advection–dispersion equation. Three lowest-order methods are initially considered and evaluation is based on comparisons with an analytical solution. For flow and dispersion parameter ranges typical of rivers and estuaries, the given boundary condition for the complete advection–dispersion equation at the end of the complete time step provides a satisfactory estimate of the intermediate boundary value. This was further confirmed by the development and evaluation of two higher-order methods. These required non-centred discrete approximations for spatial derivatives, which offset any special advantages from the higher truncation error order.     

Electrical performance, reliability and microstructure of sub-45 nm copper damascene lines fabricated with TEOS backfill

The fabrication of narrow Cu trenches using a conformal TEOS backfill approach is shown. Cu trenches with widths down to 30-40 nm were achieved. With an adequate Ta-based PVD barrier and Cu seed layer scheme, narrow Cu lines with high yield were obtained. An increase of the electrical resistivity in the narrowest dimensions was observed as a result of the size effect. Electromigration assessment demonstrated that a bilayer TaN/Ta barrier outperforms the monolayer Ta barrier. Electron backscattering diffraction (EBSD) analysis was carried out to determine grain orientation and texture in narrow copper trenches. For the first time, EBSD data reveal that Cu trenches down to 30-40 nm wide have mostly a random texture. The narrower the Cu lines get, the weaker the (1 1 1) texture with both monolayer and bilayer Ta-based barriers.