The spin Hamiltonian parameters for the two Cu centers A1 and A2 in the calcined catalysts CuO–ZnO are theoretically investigated using the high order perturbation formulas of these parameters for a 3d ion in tetragonally elongated octahedra. In the above formulas, the tetragonal field parameters Ds and Dt are determined from the superposition model, by considering the relative axial elongation...

The thermodynamic stabilities of various phases of the nitrides of the platinum-metal elements are systematically studied using density functional theory. It is shown that for the nitrides of Rh, Pd, Ir, and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures....

The finite element method has been used to simulate the properties of panels with Kagom e and tetragonal cores under compressive and shear loading. The simulation has been performed for two different materials: a Cu-alloy with extensive strain hardening and an Al-alloy with minimal hardening. It is shown that the Kagom e core is more resistant to plastic buckling than the tetragonal core under ...

We have investigated the role of the Ti-O Coulomb repulsions in the appearance of the ferroelectric state in BaTiO3 as well as the role of the Zn-O Coulomb repulsions in BiZn0.5Ti0.5O3, using a first-principles calculation with optimized structures. In tetragonal BaTiO3, it is found that the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states have an important role for the app...

Dislocation-free tetragonal hen egg white (HEW) lysozyme crystals were grown from a seed crystal in a cell. The rates of tetragonal HEW lysozyme crystal growth normal to the (110) and (101) faces with and without a 1-MHz external electric field were measured. A decrease in the typical growth rates of the crystal measured under an applied field at 1 MHz was observed, although the overall driving...

Molecular dynamics simulations, used in conjunction with a set of Born model potentials, have been employed to study oxygen transport in tetragonal La2NiO4+d. We predict an interstitialcy mechanism with an activation energy of migration of 0.51 eV in the temperature range 800–1100 K. The simulations are consistent with the most recent experiments. The prevalence of oxygen diffusion in the a–b p...

The bifunctional diaminohydroxyphosphoribosylaminopyrimidine deaminase/5-amino-6-(5-phosphoribosylamino)uracil reductase (RibD) represents a potential antibacterial drug target. The structure of recombinant Acinetobacter baumannii RibD is reported in orthorhombic and tetragonal crystal forms at 2.2 and 2.0 Å resolution, respectively. Comparisons with orthologous structures in the Protein Data B...

The copper(II) atom in the title compound, [Cu(C(5)H(10)NS(2))I(C(12)H(8)N(2))], is chelated by the N-heterocycle and the dithio-carbamate anion in a slightly distorted tetragonal coordination. The tetragonal-pyramidal coorination is completed by the iodine atom in the apical position. One ethyl group is disordered over two positions with site occupancies of 0.31 (2) and 0.69 (2).

The temperature dependence of piezoelectric, pyroelectric, and dielectric properties have been measured for 001 and 111 oriented 0.92Pb Zn1/3Nb2/3 O3–0.08PbTiO3 PZN-8%PT and 0.955Pb Zn1/3Nb2/3 O3–0.045PbTiO3 PZN-4.5%PT single crystals poled by two different poling methods, i.e., room temperature RT poling and poling through field cooling FC . Compared with the RT poling case, some interesting f...

We give an analysis of the stability and uniqueness of the simply laminated microstructure for all three tetragonal to monoclinic martensitic transformations. The energy density for tetragonal to monoclinic transformations has four rotationally invariant wells since the transformation has four variants. One of these tetragonal to monoclinic martensitic transformations corresponds to the shearin...