Papers by Keyword: Variation

Abstract: Gauge repeatability and reproducibility are becoming a versatile tool for determining the effectiveness or adequacy of manual and automatic measuring systems. The knowledge of variation is essential as variation is inherent in every measurement process and is sometimes unpredictable. Understanding and controlling variation in measurement systems is critical to reducing variability. This paper presents a design of an experiment to analyze gauge capability and uses the same designed experiment to test and compare the variation for two automatic measurement systems. Three factors were determined as a starting point and were compared at two levels. The test results were analyzed using the expanded ANOVA method in Minitab. Significant conclusions were drawn out and a recommendation for further work is suggested.

Abstract: The paper deals with the variation of resistance of selected High Performance Concrete (HPC) materials against chloride ion penetration. The resistance of chloride penetration is described by means of the diffusion coefficient and it is derived from emerging non-destructive tests. It is computed from the measurements of surface electrical resistivity (see e.g. AASTHTO TP-95 specification) data. The effect of concrete aging on the diffusion coefficient is taken into account as the concrete properties are time dependent and it is significantly important for High Performance Concrete (HPC) materials.

Abstract: Optimized design of Silicon Carbide (SiC) power devices depends, besides power device physics, also on consideration of basic properties and technological readiness of the material. This paper presents a novel analysis of the dependence of variation of epitaxial doping and thickness on the determination of the optimum design point of SiC devices. We introduce electric field at epitaxy-substrate interface as a useful parameter in controlling the dependence of device parameters on epitaxy. Using this method as criterion for design can improve the robustness of SiC devices to epitaxial variation and hence the process yield.

Abstract: Recent technology requires multistandard Radio Frequency (RF) chips for multipurpose wireless applications. In RF circuits, a low-noise amplifier (LNA) plays the key role in determining the receiver’s performance. With CMOS technology scaling, various designs has been adopted to study circuit’s characteristic and variation. In this paper, we present the results of scalable wideband LNA design based on complementary metal oxide semiconductor (CMOS), with its variance study. The design was fabricated in 180nm, 90nm, 65nm and 40nm CMOS technology.

Abstract: The process of circular saw blades sawing hedge branches belong to typical highly nonlinear penetration problems, so it is difficult to measure the actual cutting force, and it will have different characteristics with the variational saw feeding speed. The result of display dynamic analysis in the ANSYS/LS-DYNA module to circular saw blades sawing branches can be very close to the actual results. This paper make the numerical simulation for the regular pattern of cutting force with the variational saw feeding speed, analysis the force of circular with the saw feeding speed, and get some variation of circular saw blades sawing process by force, which laid foundation for the future study.

Abstract: Dynamic reactive power optimization of power system is an important means to ensure grid economic safety. Unlike static reactive power optimization, dynamic reactive power optimization has to consider the reactive power compensation devices switches and number of constraints of transformer tap stalls. The number of constraints undermine the independence of each period, each time reactive power optimization scheduling interrelated, so dynamic reactive power optimization must be considered from the entire period of time to compensate the number of constraints of the devices, and how to deal with action number of constraints is difficulty and focus of solving dynamic reactive power optimization of the power system.

Abstract: The variation on the product functional parameter has been shown to cause potential failures. These potential failures may not be caught in production line, but become the reason of customer complaints. To enable the development of robust method to detect variation, this work explores the possible sign from the data of sector reports and transforms the questioned data to the variation by Six Sigma Methodology. The key techniques of DMAIC, MVA, SPC and RSMDOE are utilized. The method is designed with three phases: firstly it is to analyze the data from the sector report to detect the peculiar value. Then the performance is evaluated to identify the variation. In the last step the issue related to the variation is solved by design optimization. The method is evaluated in the manufacturing site with the material consumption data, and the excessive 20% consumption caused by the variation is saved, which demonstrates this variation detection method is in feasible and efficient manner for quality management.

Abstract: This paper analyzed the content and distribution of Pb in surface waters in Jiaozhou Bay in 1982. Results showed that Pb content in April, June, July and October ranged from 0.49-3.25μg.L^-1, 0.45-3.35μg.L^-1, 0.30-2.67μg.L^-1 and 0.33-0.67μg.L^-1, respectively, complied with Grade I (1.00μg.L^-1) or Grade II (5.00μg.L^-1) in Sea water quality standard (GB 3097-1997) of China. As a whole, Jiaozhou Bay waters in 1982 was very lightly polluted by Pb. Non-point source was the major source of Pb in this bay, including atmosphere deposition, ocean current from the offshore, and the transportation of the head of the islands. The content, distribution and source of Pb showed significant seasonal variations, and different pollution prevention and control measurements should be took in different seasons.

Abstract: Jiaozhou Bay is located in the south of Shandong province, and is around by economic developed cities such as Qingdao, Jiaozhou and Jiaonan etc. Previous studies showed that this bay had been polluted by mercury ( Hg) in certain level. This paper is a summary of previous studies, in order to reveal the transfer process of Hg, including 1) the variation of Hg content, 2) the pollution sources of Hg, 3) land transfer process of Hg, 4) aquatic transfer process of Hg, and 5) settling process of Hg. The results of this paper were meaningful to the control of Hg pollution.

Abstract: Based on the investigation data of mercury (Hg) in both surface and bottom waters in Jiaozhou bay in 1979 to 1981, this paper tried to analysis the vertical variations of Hg contents, and to reveal the transfer processes of Hg in the bay. Results showed that, Hg pollution in the bay is mainly discharged from the major rivers, the seasonal variations of Hg content in surface waters showed a similar trend in different years, with an order of spring (or summer) > autumn. The Hg contents in bottom waters were mainly determined by the sedimentation of Hg from surface waters. There were major three transfer processes of Hg as, 1) Hg from various pollution sources was transported to streams by rainfall, 2) Hg in streamflows was discharged to surface waters of the bay, and 3) Hg in surface waters was sedimented to the bottom of the bay.