The minimum driving forces for fcc Al-based and hcp Zr-based Al-Zr solid solutions to amorphize are calculated to be about -0.05 and -0.03 eV/atom, respectively, whereas the maximum driving force is found to be -0.23 eV/atom at the alloy stoichiometry of Al(60)Zr(40). A thermodynamics parameter (gamma) over bar, defined
as the ratio of the driving force to the formation energy of the solid solution, is further proposed to indicate the glass-forming ability of an Al-Zr alloy. Thermodynamics calculations show that the glass-forming ability of the Al(56)Zr(44) alloy is the largest, implying that the Al(56)Zr(44) amorphous alloy is more ready to form than other alloys in the Al-Zr system. Besides, Voronoi analysis found that there exists a strong correlation see more between the coordinate number and structure. Amorphization could result in increase of coordinate numbers and about 1.5% volume-expansion. The volume-expansion
induced by amorphization can be attributed to two factors, i.e., the total bond number of the Al-Zr amorphous phase is greater than that of the corresponding solid solution, and the averaged bond length of the Al-Zr amorphous phase is longer than that of the corresponding solid solution. For the Al-Zr alloys, especially for the Al-Zr amorphous phase, there exists a negative chemical micro-inhomogeneity in the alloys, suggesting that metallic bonds prefer to NCT-501 inhibitor be formed between the atoms of dissimilar species. Finally, it is found that there is a weak correspondence between the bond-angle distributions of Al-Zr amorphous alloys and the solid solutions. It is further suggested that the configuration of Al-Zr amorphous alloys embodies some hybrid imprint of bcc, fcc, and hcp structures.
More interestingly, the short-range order is also observed in the bond-angle distributions. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3585869]“
“Cognitive decline in multiple sclerosis can appear early in the course of the disease and may not be evident to HM781-36B in vivo the clinician if not investigated formally. Clinical neuropsychological evaluation with these patients has main peculiarities: disabilities, fatigue, relapses, medical treatment, psychological problems, that have to be seriously taken into consideration in choosing the tests and interpreting the profile. The peculiarity of cognitive decline in MS suggests an examination primarily of attentive-executive and memory domains, with Pasat and Symbol Digit Modalities Test, strongly recommended, together with memory test. The utilization of extensive or brief cognitive batteries depends on the different goals of the neuropsychological evaluation.