RW-spaces and compactness of function spaces for L-domains

AbstractThe purpose of this paper is to study the Lawson compactness of function spaces for L-domains. A basic notion of property RW for core compact spaces is introduced, which is proved to have a close relation to the Lawson compactness of function spaces for continuous L-domains as following: (1)Every Lawson compact continuous dcpo has property RW (via the Scott topology) and for each continuous L-domain, Lawson compactness is equivalent to property RW;(2)Let P be a continuous dcpo with a least element. Then [X→P] is compact continuous for every core compact space X with property RW iff P is compact continuous L-domain;(3)Let X be a core compact space. Then [X→P] is compact for every compact continuous L-domain P iff X has property RW

Effect of austempering time on the microstructure and carbon partitioning of ultrahigh strength steel 56NiCrMoV7

Ultrahigh strength steel 56NiCrMoV7 was austempered at 270 °C for different durations in order to investigate the microstructure evolution, carbon partitioning behaviour and hardness property. Detailed microstructure has been characterised using optical microscopy and field emission gun scanning electron microscopy. A newly developed X-ray diffraction method has been employed to dissolve the bainitic/martensitic ferrite phase as two sub-phases of different tetragonal ratios, which provides quantitative analyses of the carbon partitioning between the resultant ferrites and the retained austenite. The results show that, a short-term austempering treatment was in the incubation period of the bainite transformation, which resulted in maximum hardness being equivalent to the oil-quenching treatment. The associated microstructure comprises fine carbide-free martensitic and bainitic ferrites of supersaturated carbon contents as well as carbon-rich retained austenite. In particular, the short-term austempering treatment helped prevent the formation of lengthy martensitic laths as those being found in the microstructure of oil-quenched sample. When the austempering time was increased from 20 to 80 min, progressive decrease of the hardness was associated with the evolution of the microstructure, including progressive coarsening of bainitic ferrite, carbide precipitating inside high-carbon bainitic ferrite and its subsequent decarbonisation

Can we constrain galaxy geometry parameters using spatially integrated SED fitting?

Sophisticated spectral energy distribution (SED) models describe dust attenuation and emission using geometry parameters. This treatment is natural since dust effects are driven by the underlying star-dust geometry in galaxies. An example is the Starduster SED model, which divides a galaxy into a stellar disk, a stellar bulge, and a dust disk. This work utilises the Starduster SED model to study the efficacy of inferring geometry parameters using spatially integrated SED fitting. Our method fits the SED model to mock photometry produced by combining a semi-analytic model with the same SED model. Our fitting results imply that the disk radius can be constrained, while the inclination angle, dust disk to stellar disk radius ratio, bulge radius and intrinsic bulge to total luminosity ratio are unconstrained, even though 21 filters from UV to FIR are used. We also study the impact of S/N, finding that the increase of S/N (up to 80) brings limited improvements to the results. We provide a detailed discussion to explain these findings, and point out the implications for models with more general geometry.Comment: 14 pages, 13 figures, Accepted for publication in MNRA