Statistical Evaluation of Learning Factor in Reliability Studies
A mathematical formulation is developed which allows the statistical evaluation of certain features of the probability distribution of the ratio between two random variables as in the determination of learning factors. This evaluation is of the mode, an s-confidence band for the ratio, and the effect of sample size.
Confidence Intervals for the Ratio of Two Poisson Means and Poisson Predictor Intervals
Easy-to-use charts are presented for confidence intervals for the ratio of two Poisson mean occurrence rates and for predictor intervals for the future value of a Poisson random variable, given a previously observed value. The use of the charts is illustrated and their theoretical basis is given.
Unidirectional hexagonal rare-earth disilicide nanowires on vicinal Si(100)-2×1
Rare-earth disilicide nanowires grown on vicinal Si(100) with a miscut of 2–2.5° toward the [110] azimuth at 600 °C were studied by scanning tunneling microscopy and compared with those grown on flat Si(001). In contrast to rare-earth disilicide nanowires grown on flat Si(100) surfaces, the nanowires grow unidirectionally along the [01̄1] direction of the vicinal Si(100) surface. Rare-earth disilicide nanowires form bundles composed of single nanowire units on both flat and vicinal surfaces. Yet, on the vicinal surface, the bundle width is comparable to the width of the terrace. The average nanowire length on the vicinal substrate is longer than that on the flat substrate. Scanning tunneling spectroscopy shows that the rare-earth disilicide nanowires have metallic properties.