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1.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
2.
A thermodynamic modeling of GaN was carried out to describe the thermodynamic behavior of native defects, dopants, and carriers
(free electrons and holes) in GaN semiconductors. The compound energy model (CEM) was used. An unintentionally doped GaN was
taken as an example. Oxygen was introduced into the model as the unintentionally doped impurity, according to the practical
experimental phenomena. The energies of component compounds in the model were defined based on the results of the ab initio
calculations and adjusted to fit experimental data. The thermodynamic properties of the defects and the oxygen doped were
calculated to show the facility of the model. 相似文献
3.
BACKGROUND: Systemic osteoporosis is a common and pathogenetically heterogenous complication in rheumatoid arthritis. Various factors such as disease activity, dosage and duration of glucocorticoid treatment and immobilization are involved in pathogenesis of osteoporosis in rheumatoid arthritis. INFLAMMATION AND BONE METABOLISM: Proinflammatory cytokines secreted by immunocompetent cells have a role in the regulation of the activity of osteoblasts and osteoclasts. The effects of these proinflammatory cytokines include the inhibition of bone formation and an increase in bone resorption. Interleukin-6 and nitric oxide induced in osteoblasts by proinflammatory cytokines are likely to be important mediators between these cytokines and the function of osteoblasts and osteoclasts. Furthermore, disease activity dependent changes in the secretion of glucocorticoids and in vitamin D metabolism may be involved in the pathogenesis of osteoporosis in this disease. Alteration of bone remodeling associated with immobilization is an important factor of systemic bone loss in rheumatoid arthritis. CONCLUSION: The inflammatory process in rheumatoid arthritis may cause penarticular and systemic bone loss by various cytokine and hormone mediated mechanisms. Concluding from these pathogenetic mechanisms, bisphosphonates and active vitamin D metabolites are likely to be effective therapeutic options in osteoporosis associated with rheumatoid arthritis. 相似文献
4.
5.
E Prescott M Osler PK Andersen A Bjerg HO Hein K Borch-Johnsen P Lange P Schnohr J Vestbo 《Canadian Metallurgical Quarterly》1997,26(6):1214-1218
BACKGROUND: Two recent much cited publications have raised the concern that risk associated with cigarette smoking has so far been underestimated. In this study we wish to determine whether excess all-cause mortality associated with smoking has increased during the last 20-30 years in a study population representative of the general Danish population and whether any such changes relate to changes in smoking behaviour. METHODS: Pooled data from three prospective population studies conducted in Copenhagen with detailed information on smoking habits. A total of 31,194 subjects, 17,669 males and 13,525 females, initially examined between 1964 and 1992 with examinations repeated at intervals from 1-10 years, were followed until 1995 for all-cause mortality. Relative mortality risk in smokers versus never-smokers was calculated within periods of five calendar years and compared throughout the study period. RESULTS: Male smokers' exposure did not change during the study period whereas female smokers' exposure to tobacco increased in terms of age at smoking onset, quantity smoked and depth of inhalation. During follow-up 5744 males and 2900 females died. In males, death rate ratios (comparing continuous smokers with never-smokers) did not change in the study period. In females, ratios increased from 1964-1978 to 1979-1994 by a factor of 1.3 (95% confidence interval 1.0-1.8). CONCLUSIONS: In agreement with the observed changes in smoking habits, excess mortality in male smokers did not increase whereas excess mortality in female smokers increased slightly. 相似文献
6.
W. Hein 《e & i Elektrotechnik und Informationstechnik》1998,115(11):605-607
The Kyoto Protocol to the United Nationsl Framework Convention on Climate Change gives a target for the reduction of greenhouse gases in the EU and most associated states of 8% from 1990 levels to 2010. The European Commissions Whitebook on Renewable Energy is setting a target of doubling the share of Renewable Energy from 6% now to 12% in 2010 for the European Union. There is no contradiction between these targets. 相似文献
7.
Z Chen A Spies R Hein X Zhou BC Thomas ML Richter P Gegenheimer 《Canadian Metallurgical Quarterly》1995,270(29):17124-17132
F1F0-ATP synthases utilize protein conformational changes induced by a transmembrane proton gradient to synthesize ATP. The allosteric cooperativity of these multisubunit enzymes presumably requires numerous protein-protein interactions within the enzyme complex. To correlate known in vitro changes in subunit structure with in vivo allosteric interactions, we introduced the beta subunit of spinach chloroplast coupling factor 1 ATP into a bacterial F1 ATP synthase. A cloned atpB gene, encoding the complete chloroplast beta subunit, complemented a chromosomal deletion of the cognate uncD gene in Escherichia coli and was incorporated into a functional hybrid F1 ATP synthase. The cysteine residue at position 63 in chloroplast beta is known to be located at the interface between alpha and beta subunits and to be conformationally coupled, in vitro, to the nucleotide binding site > 40 A away. Enlarging the side chain of chloroplast coupling factor 1 beta residue 63 from Cys to Trp blocked ATP synthesis in vivo without significantly impairing ATPase activity or ADP binding in vitro. The in vivo coupling of nucleotide binding at catalytic sites to transmembrane proton movement may thus involve an interaction, via conformational changes, between the amino-terminal domains of the alpha and beta subunits. 相似文献
8.
A. Filzwieser K. Hein G. Mori 《JOM Journal of the Minerals, Metals and Materials Society》2002,54(4):28-31
The knowledge of limiting current density and thickness of diffusion boundary layer is particularly important in improving
space-time-yield of electrolysis and especially of high current-density electrolysis. Both natural and forced convection of
electrolyte flow are considered in the presented computational fluid dynamics model for calculation of these values. Natural
convection is modeled by implementation of a source term at the cathode surface for copper concentration according to Faraday’s
law, which allows calculation of electrolyte density for each volume cell of the grid. Forced convection is considered as
flow of electrolyte through the cell generated by electrolyte inlet and outlet. By variation of current density, the limiting
current density can be calculated with a copperion concentration of zero at the cathode surface after reaching the steady-state
conditions in electrolyte. Time dependency of diffusion boundary layer thickness is shown for a chosen cell geometry. Literature
data and measured and calculated values of both quantities are in good agreement. 相似文献
9.
Reviews the predominant models developed by researchers to assess the psychological adaptation of immigrants in the host society. The use of the terms assimilation and acculturation to reflect the process of change undergone by immigrants is discussed. Although these terms have been used interchangeably, the outcome of change is very different in each. The difference between assimilation and acculturation is reflected in the models of adaptation regrouped under linear and bidimensional models. A 3rd model, called orthogonal cultural identification, is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Different modes of activation are described for a postgrafting reaction of acrylic acid on poly(p-phenylene terephthalamid) (PPTA)mitrogen plasma or electron-beam irradiation. Both lead to surface radical formation, and these species are able to initiate grafting. The Functionalization through amino group attachment is characteristic of plasma treatment. Degradation initiated by UV-visible emission of plasma is noticed, leading to the amide clivage. The surface grafting is more important when the PPTA is irradiated with a cold plasma and if water is used as the solvent. The polymer crystallinity degree reduces the grafting of the electron beam-irradiated PPTA even with a high radical concentration. © 1994 John Wiley & Sons, Inc. 相似文献