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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Segregation Of Bismuth To Triple Junctions In Copper, K.-M. Yin, Alexander H. King, T.E. Hsieh, F.-R. Chen, J.J. Kai, L. Chang
Segregation Of Bismuth To Triple Junctions In Copper, K.-M. Yin, Alexander H. King, T.E. Hsieh, F.-R. Chen, J.J. Kai, L. Chang
Alexander H. King
Bismuth segregation in copper has been studied using energy-dispersive X-ray spectrometry (EDX) in a JEOL 2010F transmission electron microscope. In addition to the expected solute enrichment at grain boundaries, we have observed extremely high concentrations of bismuth at certain triple junctions, with significantly greater enrichment factors than in the adjacent grain boundaries. It is shown here that the triple junction segregation is a function of the parameters of the grain boundaries at the triple line, and existence of this type of segregation implies that the affected triple junctions embody excess free energy. At least one of the observed triple junctions …
Vibrational Spectra In Ordered And Disordered Ni3al, Jeffrey D. Althoff, Dane Morgan, Didier De Fontaine, Mark Asta, S. M. Foiles, Duane D. Johnson
Vibrational Spectra In Ordered And Disordered Ni3al, Jeffrey D. Althoff, Dane Morgan, Didier De Fontaine, Mark Asta, S. M. Foiles, Duane D. Johnson
Duane D. Johnson
We calculate the vibrational density of states (DOS) and corresponding thermodynamic properties of L12 ordered and disordered Ni3Al in the quasiharmonic approximation using the embedded-atom method. Vibrational and thermodynamic properties, including vibrational entropy differences between ordered and disordered states, are found to be in good agreement with experiment. The DOS of the configurationally disordered alloy resembles a broadened version of the DOS of the L12 phase, not a one-atom per cell fcc DOS, and is shifted downward in frequency because the disordered state has a larger volume than the ordered phase. Calculations of the projected DOS indicate that high-frequency modes …
Experimental And Theoretical Investigations Of Order-Disorder In Cu2almn, Duane D. Johnson, M. Asta, J. J. Hoyt, B. C. Chakoumakos, S. T. Misture, J. D. Althoff, R. Mccormack
Experimental And Theoretical Investigations Of Order-Disorder In Cu2almn, Duane D. Johnson, M. Asta, J. J. Hoyt, B. C. Chakoumakos, S. T. Misture, J. D. Althoff, R. Mccormack
Duane D. Johnson
A combination of X-ray and neutron powder diffraction has been used to measure the two long range order parameters vs. temperature below the disorder-B2 transition in the ternary alloy Cu2 AlMn. The results indicate that at temperatures just below the critical point the Al + Mn sublattice is enriched in Al. First-principles calculations based on only the atomic numbers of Cu, Mn and Al support the experimentally-observed preference of Al for the Al + Mn sublattice, and reveal the interplay between the constituent binary systems that gives rise to this behavior.
Low Pressure Synthesis Of Bulk, Polycrystalline Gallium Nitride, Alberto Argoitia, Cliff C. Hayman, John C. Angus, Long Wang, Jeffrey S. Dyck, Kathleen Kash
Low Pressure Synthesis Of Bulk, Polycrystalline Gallium Nitride, Alberto Argoitia, Cliff C. Hayman, John C. Angus, Long Wang, Jeffrey S. Dyck, Kathleen Kash
Jeffrey Dyck
Thick films of polycrystalline GaN were grown at low pressures by direct reaction of atomic nitrogen with liquid Ga without the presence of a substrate. The crystals were confirmed to be wurtzitic GaN by x-ray diffraction, transmission electron microscopy, Raman spectroscopy, and elemental analysis. Photoluminescence spectra showed near band edge peaks and broad yellow band emission at both 298 and 10 K. The results show that atomic nitrogen is an attractive alternative to high pressure N2 for the saturation of liquid gallium with nitrogen for the synthesis of bulk GaN.
Nmr And Vortex Lattice Melting In Yba2cu3o7, Charles Recchia, J Martindale, C Pennington, W Hults, J Smith
Nmr And Vortex Lattice Melting In Yba2cu3o7, Charles Recchia, J Martindale, C Pennington, W Hults, J Smith
Charles H Recchia
No abstract provided.
Local Nonequilibrium Transport Models, Sergey Sobolev
Local Nonequilibrium Transport Models, Sergey Sobolev
Sergey Sobolev
No abstract provided.
Local Non-Equilibrium Diffusion Effects On The Kinetic Phase Boundaries In Solidification, Sergey Sobolev
Local Non-Equilibrium Diffusion Effects On The Kinetic Phase Boundaries In Solidification, Sergey Sobolev
Sergey Sobolev
No abstract provided.
Internal Forces In Nondegenerate 2d Electron Systems, Christopher Fang-Yen, M Dykman, M Lea
Internal Forces In Nondegenerate 2d Electron Systems, Christopher Fang-Yen, M Dykman, M Lea
Christopher Fang-Yen
No abstract provided.