In this paper, the effect of elliptical shape openings was numerically compared to the case when circular openings were used in the steel panel shear walls. At first, the finite element model in ABAQUS was calibrated by experimental results, obtained from previous studies. Then, three steel shear panels with different sizes of elliptical openings were analyzed under cyclic loads, and the result...

The dependencies on strain and oxygen vacancies of the ferroelectric polarization and the weak ferromagnetic magnetization in the multiferroic material bismuth ferrite, BiFeO3, are investigated using first principles density functional theory calculations. The electric polarization is found to be rather independent of strain, in striking contrast to most conventional perovskite ferroelectrics. ...

Oxygen vacancies have been implicitly assumed isolated ones, and understanding oxide materials possibly containing oxygen vacancies remains elusive within the scheme of the isolated vacancies, although the oxygen vacancies have been playing a decisive role in oxide materials. Here, we report the presence of oxygen vacancy linear clusters and their orientation along a specific crystallographic d...

The density of oxygen vacancies characterization in high-k/metal gate is significant for semiconductor device fabrication. In this work, a new approach was demonstrated to detect the density of oxygen vacancies by in situ x-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) measurement. Moreover, the band alignment of the structure with optical band gap measur...

Based on the ab initio electronic structure calculations the picture of ferromagnetism in polimerized C60 is proposed which seems to explain the whole set of controversial experimental data. We have demonstrated that, in contrast with cubic fullerene, in rhombohedral C60 the segregation of iron atoms is energetically unfavorable which is a strong argument in favor of intrinsic character of carb...

Band structure calculations are presented for large supercells of Ba2CuO4 (BCO) with O-vacancies in planar or apical positions, and of superoxygenated La2CuO4 (LCO) with oxygen interstitials in the La2O2 layers. It is found that apical oxygen vacancies in BCO act as electron dopants and makes the electronic structure similar to that of hole doped LCO. Excess oxygen interstitials forming wires i...

This article reports positron annihilation spectroscopy and calorimetric measurements of the aging behavior in a Cu–Al–Be shape memory alloy. An excess of single vacancies is retained in the alloy as a result of a quench. All vacancies in excess disappear after long aging time, and a migration energy EM51.060.1 eV for this process has been found to be larger than in other Cu-based shape memory ...

Novel self-activated yellow-emitting BaLuAlxZn4-xO7-(1-x)/2 photoluminescent materials were investigated by a combined experimental and theoretical analysis. The effects of Al/Zn composition modulation, calcination atmosphere and temperature on the crystal structure and photoluminescence properties have been studied via engineering oxygen vacancies. Accordingly, BaLuAl0.91Zn3.09O7 prepared in a...

Design of thinned semi-elliptical and quarter-elliptical antenna arrays, with uniform excitation and uniform spacing using genetic algorithm (GA) optimization, is presented in this paper. Thinned arrays produce narrow directive beam without causing major degradation of fully populated antenna arrays. Semi-elliptical array contains antenna elements along half of the elliptical geometry and quart...

The electron dynamics in a TiO(2)/alizarin based dye-sensitized solar cell is studied by a means of ab initio nonadiabatic molecular dynamics. The effects of surface terminations and vacancy defects on photoexcited interfacial electron transfer (ET) and energy relaxation of injected electrons are examined in detail. In particular, we consider three plausible TiO(2) surface terminations which ar...