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141.
Michael B. C. Khoo 《Quality Engineering》2005,17(3):453-458
A semicircle control chart can be used in detecting both increases and decreases in the mean and/or variance. In this paper, we propose two modified semicircle charts for detecting a reduction in the process variance, a.k.a. process improvement. Each of these modified semicircle charts, namely, SC1 and SC2 has two limits, defined by the inner and outer semicircles. A process improvement is detected by the SC1 scheme if a point is plotted inside the smallest semicircle, or if two successive points are plotted between the inner and outer semicircles and by the SC2 scheme if a point plots inside the smallest semicircle or if two of three successive points plot between the inner and outer semicircles. It will be shown that the two modified semicircle charts have superior average run length (ARL) performances to the basic semicircle chart in the detection of process improvement. The ARL study is conducted by means of a simulation. 相似文献
142.
In this article, particle size distributions (PSDs) measured by different techniques, including image analysis (IA), laser diffraction (LD), ultrasonic attenuation spectroscopy (UAS), and focused-beam reflectance measurement (FBRM), are compared for spherical glass beads and nonspherical silica flakes. It is shown that particle shape strongly affects the results obtained by different techniques. For spheres, the PSDs obtained by IA, LD, and UAS agree well. There is no consistent result among different particle measurement techniques for nonspherical particles. The conversion between PSDs obtained by IA, LD, and UAS has been based on particle shape factors. Caution must be exercised when a measured chord length distribution (CLD) is used to indicate the PSD during a process because the CLD result obtained by FBRM is complex, depending not only on the PSD, but also on particle optical properties and shape. 相似文献
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The upward bubble velocity and the pierce length distributions in a sectional water model of the copper converter in Guixi Smelter in Jiangxi, China, were measured using a two-contact electro-resistivity probe. In the case of using a single tuyere, the bubble velocity distribution along longitudinal direction was similar to that derived from Guassian function. Beyond the center of the longitudinal range, the bubble pierce length exhibited a sudden increase. The upward bubble velocity at a specified location could go up to meters per second. Its probability at a fixed location obeys a lognormal function; the bubble pierce length there varies bellow a few centimeters. In the case of using multi-tuyeres, the upward bubble velocity was roughly uniform right above the tuyeres and showed a slow decrease beyond this region. The bubble pierce length within both of these two regions was roughly uniform. Its average value in the former region, however, was found to be somewhat lower than that in the later. 相似文献
147.
介绍了电子储存环中偏转磁铁入口和出口处的非均匀磁场产生的辐射——边缘辐射,给出了零边缘长度、有限边缘长度、有限直线节长度条件下的辐射通量和亮度分布,通过与常规同步辐射场的比较,充分说明了边缘辐射是一种优良的红外同步辐射光源。 相似文献
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在线路升高改造中,由于线路局部升高,将引起线长的变化,因此需计算导线和地线的应力来进行线长调整,否则可能导致该耐张段应力增加。为此提出了一种试算方法——降温替代法,并通过实例详细说明了该方法的计算过程。 相似文献
150.
大电流真空电弧特性的研究与分析 总被引:6,自引:2,他引:6
本文分析并介绍了大电流时纵向磁场,触头开距,触头半径等对电弧特性的影响,可为高压大容量直空断路器设计提供参考。 相似文献