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Solution Structural Studies of Pre-amyloid Oligomer States of the Biofilm Protein Aap
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Role of short range order on crystallization of tectosilicate glasses: A diffraction study
Abstract not provided
Density functional theory study of the point defect energetics in y- LiAlO2, Li2ZrO3 and Li2TiO3 materials
The defect energetics in y-LiAlO2, Li2 TiO3, and Li2ZrO3 materials used in tritium-producing burnable absorber rods and fusion solid breeder applications was investigated using density functional theory calculations. A comprehensive analysis of the charged defects was performed for cation and anion vacancies, interstitials, antisite defects, and 3H interstitial and substitutional defects to understand the defect structures at different charge states and their stability as a function of the electron chemical potential across the electronic band gap of crystals at operating temperature and oxygen partial pressure conditions. Through investigation of the local bonding configurations and projected electronic density of states of the 3H related charged defects, including 3H interstitial (3Hint), 3Hint bound with an oxygen interstitial, and substitutional 3H defects on the Li, O, and M (M¼ Al, Ti, and Zr) sites (3HLi, 3HO, and 3HM), the 3H states of these defects were distinguished, i.e. triton (3Hþ), neutral 3H (3H0), and tritide (3H-). The two stable 3H related defects under the Li2O-LiOH rich condition at T ¼ 1000 K, between P(O2) ¼ 10^-5 and 10^-25 atm were found to be 3H interstitial (3Hint) with charge of þ1 and neutral 3HLi (substitutional 3H on the Li site) in g-LiAlO2, Li2ZrO3, and Li2TiO3 materials. For Li2TiO3, the stability of the 3HO with charge of þ1 and 3HM with charge of 3 becomes comparable to that of 3Hint atm at P(O2) ¼ 1025 atm. Overall, our results indicate the energy cost to form the stable 3H defect species (3Hint with charge of þ1 and neutral 3HLi) in g-LiAlO2 material are higher than those of Li2TiO3 and Li2ZrO3 materials at T ¼ 1000 K, between P(O2) ¼ 10^-5 and 10^-25 atm. Interactions between the point defects and the 3H species as a function of the electron chemical potential across the band gap of the materials were also examined. All the three materials exhibit strong interactions between the 3Hint and the O vacancy, Li vacancy, and O interstitial defects with the strongest interactions found in the case of y-LiAlO2 phase, indicating a higher tendency to trap 3H at such point defects in y-LiAlO2.
Theoretical study of the electronic, thermodynamic, and thermo-conductive properties of y-LiAlO2 with 6Li isotope substitutions for tritium production
Lithium aluminate has attracted researchers’ interests due to its wide applications. The structural, electronic, optical, lattice phonon thermodynamic, and thermo-conductive properties of ?-LiAlO2 with 6Li-isotope substitution are investigated by density functional theory and lattice phonon dynamics. The calculated results show that ?-LiAlO2 possesses a wide band-gap of 4.63 eV. The valence band is mainly formed by p orbitals of Li, O, and Al. The calculated lattice thermal conductivity of ?-LiAlO2 is found to be in good agreement over a wide range of temperatures with the available experimental data. The calculated dielectric matrix shows anisotropic behavior along z and x (or y) axes. Due to the wide band-gap, the optical conductivity of ?-LiAlO2 is mainly contributed from the electron hopping between valence-conduction bands. Substitution of 7Li with 6Li isotope in ?-LiAlO2 leads to observable differences in the lattice phonon frequencies at higher frequencies (>8THz) and to slight changes in corresponding thermal conductivity and the infrared and Raman spectra which are in good agreement with the measured data. The relevance of these properties for tritium production through 6Li absorbing neutron in nuclear reactors is discussed.
Multi-scale thermal stability study of commercial lithium-ion batteries as a function of chemistry and state-of-charge.
Abstract not provided.
Fabric and anisotropy of slates: From classical studies to new results
Abstract not provided
High-pressure, low-temperature studies of phase transitions in SrRuO3 – Absence of volume collapse
Not Available
Numerical study of damage in particulate composites during high-strain rate loading using novel damage model
Not provided.