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Full-Text Articles in Physics
Posterminaries: After Nabarro, Alexander H. King
Posterminaries: After Nabarro, Alexander H. King
Alexander H. King
With the passing of Frank Nabarro in July of this year, we have lost one of the founding fathers of materials science. His name appears in many of the textbooks from which we train our students today, and also on the spines of several volumes on dislocation theory, including his classic monograph on the subject. He rightly stands among the gods of our field. Ninety years old at his death, he was a sprightly dancer at the frontiers of knowledge, right up to the end.
Comment On “Structural Stability Of Complex Hydrides: Libh4 Revisited”, Duane D. Johnson, Nikolai A. Zarkevich
Comment On “Structural Stability Of Complex Hydrides: Libh4 Revisited”, Duane D. Johnson, Nikolai A. Zarkevich
Duane D. Johnson
A Comment on the Letter by Zbigniew Łodziana and Tejs Vegge, Phys. Rev. Lett. 93, 145501 (2004).
Posterminaries: The Scales Of Judgement, Alexander H. King
Posterminaries: The Scales Of Judgement, Alexander H. King
Alexander H. King
Materials scientists are generally well-versed in physics, and physics, above all, is a science of measurements. The first instinct of a physicist is to parse a problem in terms of its measurables in the dimensions of mass, length, and time, and it is the shifting of attention down the scale of length that particularly characterizes our present times as the Nano Age.
Posterminaries: Plain Text, Alexander H. King
Posterminaries: Plain Text, Alexander H. King
Alexander H. King
You just can’t win an argument with an English professor.
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Alexander H. King
Thermal effects on domain orientation in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) have been investigated by using in situ x-ray diffraction with an area detector. In the case of a soft PZT, it is found that the texture parameter called multiples of a random distribution (MRD) initially increases with temperature up to approximately 100 °C and then falls to unity at temperatures approaching the Curie temperature, whereas the MRD of hard PZT and PT initially undergoes a smaller increase or no change. The relationship between the mechanical strain energy and domain wall mobility with temperature is discussed.
Recycling Krylov Subspaces For Sequences Of Linear Systems, Michael L. Parks, Eric De Sturler, Greg Mackey, Duane D. Johnson, Spandan Maiti
Recycling Krylov Subspaces For Sequences Of Linear Systems, Michael L. Parks, Eric De Sturler, Greg Mackey, Duane D. Johnson, Spandan Maiti
Duane D. Johnson
Many problems in science and engineering require the solution of a long sequence of slowly changing linear systems. We propose and analyze two methods that significantly reduce the total number of matrix‐vector products required to solve all systems. We consider the general case where both the matrix and right‐hand side change, and we make no assumptions regarding the change in the right‐hand sides. Furthermore, we consider general nonsingular matrices, and we do not assume that all matrices are pairwise close or that the sequence of matrices converges to a particular matrix. Our methods work well under these general assumptions, and …
Solute/Defect-Mediated Pathway For Rapid Nanoprecipitation In Solid Solutions: Γ Surface Analysis In Fcc Al-Ag, Daniel Finkenstadt, Duane D. Johnson
Solute/Defect-Mediated Pathway For Rapid Nanoprecipitation In Solid Solutions: Γ Surface Analysis In Fcc Al-Ag, Daniel Finkenstadt, Duane D. Johnson
Duane D. Johnson
In face-centered-cubic (fcc) Al, stacking fault energy (SFE) is high at ca. 150mJ/m2, inhibiting stacking fault (SF) formation and dislocation motion. Yet Ag-rich hcp precipitates form rapidly in Al-rich fcc Al-Ag, even as the energy difference ΔEhcp−fcc between hcp and fcc homogeneous solid solution increases with Ag content. Using electronic density functional theory methods, we calculate the SFE γSF versus distance of Ag (111) planes from intrinsic (isf), extrinsic (esf) and twin (tsf) SFs. We find that an inhomogeneous distribution of Ag solute segregated in layers adjacent to SFs leads to favorable SFE, a manifestation of the well-known Suzuki effect. …
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Duane D. Johnson
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu–xAl (x=0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γutstacking faultenergies (SFEs). Our results reveal an increased tendency of Cu–Al to deform preferentially by twinning with increasing Al content, consistent with experiment. We attribute this mechanical behavior to appreciable lowering of the twinning barrier γut, along with the stable intrinsic and twin SFEs.