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排序方式: 共有1161条查询结果,搜索用时 265 毫秒
41.
J. Madison J. E. Spowart D. J. Rowenhorst L. K. Aagesen K. Thornton T. M. Pollock 《Metallurgical and Materials Transactions A》2012,43(1):369-380
Fluid flow within the dendritic structure at the solid–liquid interface in nickel-based superalloys has been studied in two
directionally solidified alloy systems. Millimeter-scale, three-dimensional (3D) datasets of dendritic structure have been
collected by serial sectioning, and the reconstructed mushy zones have been used as domains for fluid-flow modeling. Flow
permeability and the influence of dendritic structure on flow patterns have been investigated. Permeability analyses indicate
that the cross flow normal to the withdrawal direction limits the development of flow instabilities. Local Rayleigh numbers
calculated using the permeabilities extracted from the 3D dataset are higher than predicted by conventional empirical calculations
in the regions of the mushy zone that are prone to the onset of convective instabilities. The ability to measure dendrite
surface area in 3D volumes permit improved prediction of permeability as well. 相似文献
42.
Karl Fraser Scott J. Harrison Geoff A. Lane Don E. Otter Yacine Hemar Siew-Young Quek Susanne Rasmussen 《Food chemistry》2012
Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the potential of HILIC chromatography combined with non-targeted mass spectrometric methods to provide a comprehensive understanding of polar metabolites in plant extracts. 相似文献
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Abstract The use of information technology (IT) in developing countries has attracted a considerable amount of attention in recent years. However, the research in this area is largely fragmented, and there is a need to consolidate efforts in order to make research more effective. Theory can provide a basis for this consolidation process by allowing communication between different researchers and also between researchers and practitioners. The primary objective of this paper is to describe aspects of the state of existing theory in the field of IT in developing countries, and discuss possible research directions for the future. A total of 199 articles were analyzed to describe existing research themes, and future directions are discussed in terms of level of analysis, research methods, and research reports. 相似文献
46.
Rout Bapin Kumar Brooks Geoff Subagyo Rhamdhani M. Akbar Li Zushu 《Metallurgical and Materials Transactions B》2016,47(6):3350-3361
Metallurgical and Materials Transactions B - Quantification of metal droplets ejected due to impinging gas jet on the surface of liquid metal is an important parameter for the understanding and for... 相似文献
47.
Geoff Giordano 《Plastics Engineering》2019,75(1):28-35
The global push toward finalizing and implementing the next generation of connected smart machinery—the Industry 4.0 protocols—begs the question: how will these new standards influence equipment purchasing decisions for plastics manufacturers? 相似文献
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