9 = 0.6 I / s ' 7 = 6.0 0 7 = 2 4 i ti 3 = 6 0 Through close control over green-state powder processing, pure alumina ceramics of 0.5-pm grain size were obtained by sintering at 1250°C. The static grain growth of this material was modest at temperatures below 1300°C. However, dynamic grain growth occurred rapidly during superplastic deformation. Therefore, although the ultrafine-grained alumina...

in the present study, an ultrafine grained (ufg) 304l stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. weldability of the ufg sample was studied by nd: yag laser welding under different welding conditions. taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

Epidemiological and toxicological studies have suggested that the health effects associated with exposure to particulate matter (PM) are related to the different physicochemical properties of PM. These effects occur through the initiation of differential cellular responses including: the induction of antioxidant defenses, proinflammatory responses, and ultimately cell death. The main objective ...

austenitic stainless steels are extensively used in various applications requiring good corrosion resistance and formability. in the current study, the formation of nano/ ultrafine grained austenitic microstructure in a microalloyed aisi 304l stainless steel was investigated by the advanced thermomechanical process of reversion of strain-induced martensite. for this purpose, samples were subjec...

background: it has been shown that inhalation of carbonaceous particulate matter may impair lung function in children. objective: using the carbon content of airway macrophages as a marker of individual exposure to particulate matter derived from fossil fuel, we sought direct evidence for this association. methods: 300 children from puffed rice industrial areas and 300 children from population ...

How do the electronic properties of a metal atom change when clusters of different sizes and geometry are formed? Nilius et al. (p. 1853) used scanning tunneling microscopy (STM) to build gold chains with defined numbers of atoms on a nickel-aluminum alloy surface. They then used the STM to perform scanning tunneling spectroscopy on these structures. Conductivity spectra taken at 30 points alon...

Ultrafine-grained (UFG) metallic materials are at the cutting edge of modern materials science as they exhibit outstanding properties which make them very interesting for prospective structural or functional engineering applications. Due to the progress in severe plastic deformation techniques during the last decade, ultrafine-grained microstructures are no longer only restricted to easy to def...

A review of the physical characteristics of sulfur-containing aerosols, with respect to size distribution of the physical distribution, sulfur distributions, distribution modal characteristics, nuclei formation rates, aerosol growth characteristics, and in situ measurement, has been made. Physical size distributions can be characterized well by a trimodal model consisting of three additive log-...

Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid M. Ehn, T. Petäjä, H. Aufmhoff, P. Aalto, K. Hämeri, F. Arnold, A. Laaksonen, and M. Kulmala Division of Atmospheric Sciences, Department of Physical Sciences, P.O. Box 64, 00014 University of Helsinki, Finland Max-Planck Institute for Nuclear Physics (MPI...

Grain refinement can make conventional metals several times stronger, but this comes at dramatic loss of ductility. Here we report a heterogeneous lamella structure in Ti produced by asymmetric rolling and partial recrystallization that can produce an unprecedented property combination: as strong as ultrafine-grained metal and at the same time as ductile as conventional coarse-grained metal. It...