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- Euchner, H., et al.
(författare)
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Anomalous vibrational dynamics in the Mg2Zn11 phase
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 83:14, s. 144202-
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Tidskriftsartikel (refereegranskat)abstract
- We present a combined experimental and theoretical study of the structure and the lattice dynamics in the complex metallic alloy Mg2Zn11, by means of neutron and x-ray scattering, as well as ab initio and empirical potential calculations. Mg2Zn11 can be seen as an intermediate step in structural complexity between the simple Laves-phase MgZn2 on one side, and the complex 1/1 approximants and quasicrystals ZnMgAl and Zn(Mg)Sc on the other. The structure can be described as a cubic packing of a triacontahedron whose center is partially occupied by a Zn atom. This partially occupied site turned out to play a major role in understanding the lattice dynamics. Data from inelastic neutron scattering evidence a Van Hove singularity in the vibrational spectrum of Mg2Zn11 for an energy as low as 4.5 meV, which is a unique feature for a nearly-close-packed metallic alloy. This corresponds to a gap opening at the Brillouin zone boundary and an interaction between a low-lying optical branch and an acoustic one, as could be deduced from the dispersion relation measured by inelastic x-ray scattering. Second, the measured phonon density of states exhibits many maxima, indicating strong mode interactions across the whole energy range. The origin of the low-energy modes in Mg2Zn11 and other features of the vibrational spectra are studied, using both ab initio and empirical potential calculations. A detailed analysis of vibrational eigenmodes is presented, linking features in the vibrational spectrum to atomic motions within structural building blocks.
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3. |
- Euchner, H., et al.
(författare)
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Anomalous vibrational dynamics in the Mg(2)Zn(11) phase
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 83:14, s. 144202-
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Tidskriftsartikel (refereegranskat)abstract
- We present a combined experimental and theoretical study of the structure and the lattice dynamics in the complex metallic alloy Mg(2)Zn(11), by means of neutron and x-ray scattering, as well as ab initio and empirical potential calculations. Mg(2)Zn(11) can be seen as an intermediate step in structural complexity between the simple Laves-phase MgZn(2) on one side, and the complex 1/1 approximants and quasicrystals ZnMgAl and Zn(Mg)Sc on the other. The structure can be described as a cubic packing of a triacontahedron whose center is partially occupied by a Zn atom. This partially occupied site turned out to play a major role in understanding the lattice dynamics. Data from inelastic neutron scattering evidence a Van Hove singularity in the vibrational spectrum of Mg(2)Zn(11) for an energy as low as 4.5 meV, which is a unique feature for a nearly-close-packed metallic alloy. This corresponds to a gap opening at the Brillouin zone boundary and an interaction between a low-lying optical branch and an acoustic one, as could be deduced from the dispersion relation measured by inelastic x-ray scattering. Second, the measured phonon density of states exhibits many maxima, indicating strong mode interactions across the whole energy range. The origin of the low-energy modes in Mg(2)Zn(11) and other features of the vibrational spectra are studied, using both ab initio and empirical potential calculations. A detailed analysis of vibrational eigenmodes is presented, linking features in the vibrational spectrum to atomic motions within structural building blocks.
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4. |
- Feuerbacher, M., et al.
(författare)
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The Samson phase, β-Mg2Al3, Revisited
- 2007
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Ingår i: Zeitschrift für Kristallographie. - 0044-2968. ; 222:6, s. 259-288
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Tidskriftsartikel (refereegranskat)
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8. |
- Simak, S. I., et al.
(författare)
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Gallium and indium under high pressure
- 2000
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 85:1, s. 142-145
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Tidskriftsartikel (refereegranskat)
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10. |
- Ahlstedt, S, et al.
(författare)
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Evaluation of circulating immune complex-like material for development of skin reactions in connection with penicillin therapy
- 1981
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Ingår i: International Archives of Allergy and Applied Immunology. - 0020-5915. ; 64:2, s. 195-200
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Tidskriftsartikel (refereegranskat)abstract
- The levels of immune complex-like material in serum from 18 patients in connection with skin eruptions appearing during penicillin therapy were determined with a modified ELISA. Immune complex-like material could only be shown in the serum of 3 out of the 17 patients. However, according to ELISA results, the complexes appeared without the simultaneous presence of penicilloyl-specific antibodies. Neither could penicilloyl-specific antibodies be recorded in 9 patient treated with parenteral penicillin without adverse reactions. 3 of these patients had immune complex-like material in their serum. It was concluded that immune complex-like material with penicilloyl specificity is not likely to contribute to the development of skin eruptions often seen in connection with penicillin treatment.
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