Materials Literature
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A recently proposed linear-scaling scheme for density-functional pseudopotential calculations is described in detail. The method is based on a formulation of density functional theory in which the ground state energy is determined by minimization with respect to the density matrix, subject to the condition that the ei…
The switching of the sandwich structure ‘‘ferroelectric+thin dielectric layer’’ is theoretically studied. The behavior of the remanent polarization, Pr, coercive field, Ec, maximal polarization on the loop, Ps, and the slope of the hysteresis loop at Ec as a function of both, the relative thickness of the layer (the t…
Crystal structures and magnetic properties for off-stochiometric R 2 Fe 14 Ga 2 (R=Y, Nd and Sm) have been studied by using X-ray diffraction, magnetic measurements and Mossbauer spectra. All compounds have the Tb 2 Zn 17 structure. The Curie temperatures increase by about 150-200 degrees C over those for the correspo…
The proposed continuum model describes thin film nucleation and growth from a unique point of view for the whole region of supersaturations (both the metastable region of small supersaturations and the unstable region of high supersaturations). The early stage of thin-film formation is presented as a relaxation proces…
Glycine-124 and leucine-307 of phenylalanine dehydrogenase from Bacillus sphaericus were altered by site-specific mutagenesis to the corresponding residues in leucine dehydrogenase: alanine and valine, respectively. These two residues have previously been implicated from molecular modelling as important in determining…
The motion of charged particles in electric fields can be harmful to gas-insulated apparatus, or may be used beneficially in several electrostatic technologies, such as printing, coating and separation of mixed granular solids. The theoretical analysis and the experimental data demonstrate the existence of numerous fa…
Equilibrium molecular dynamics is used to simulate fluids comprised of chains of tangent hard spheres. Reptation theory predictions of segmental motion are compared with simulation results. In addition to the usual tube confinement, a second entanglement effect is observed. As the chain disengages from the tube, persi…
Surface freezing of a crystalline monolayer has been observed at the free surface of liquid binary mixtures of normal alkanes by x-ray and surface tension measurements. Two dramatically different behaviors are found for the monolayer properties depending on $\ensuremath{\Delta}n$, the difference in the components' car…
The incorporation of hydrogen into Si, under different electrochemical conditions including anodization in fluoride solutions where porous silicon is formed, is studied by NRA and in situ capacitance measurements. Results suggest a large near surface concentration of H whilst simulation show that the maximum penetrati…
Oxides of the La 1-x Pb x MnO 3 system show giant magnetoresistance around 300 K. In La 1-x Pb x MnO 3 the magnitude of the magnetoresistance (MR) at 320 K is 85% at 6 T and it is nearly temperature independent over a temperature range 40-320 K. All the compositions (0.1<or=x<or=0.5) show a peak in resistivity around…
Surface potential decay after charge deposition by corona or contact has been studied for epoxy samples and compared with polarization measurements. We show that the classical interpretation of the potential decay in terms of the injection of the deposited charge into the volume of the insulator does not account for o…
The synthesis of plasma-polymerized tetraethoxysilane (TEOS) and hexamethyldisiloxane (HMDSO) thin films by atmospheric pressure glow (APG) discharge was investigated and the characteristics of this method were compared with those of low-pressure plasma-enhanced CVD (LPPECVD) methods. The obtained films had smooth sur…
${\mathrm{CN}}_{x}$ films were found to have a distorted graphitelike microstructure consisting of buckled and curved basal planes using high-resolution electron microscopy. Nanoindentation showed an elastic recovery of 85%, and a hardness of $\ensuremath{\sim}60$ GPa. Based on detailed quantum chemical calculations a…
This study investigated a model theory of the changes in magnetization that a ferromagnetic material undergoes when subjected to an applied uniaxial stress. The description of these effects is shown to be totally different from the description of the changes in the hysteresis curve under a series of constant applied s…
Polarization aberrations due to varying polarization state across the field of view (FOV) are investigated for crossed folding mirrors. We define crossed mirrors as oriented in space such that s-polarized light incident on the first mirror is p-polarized at the second mirror. This completely compensates for polarizati…
In the molecular scheme of living organisms, adenosine 3',5'-monophosphate (cyclic AMP or cAMP) has been a universal second messenger. In eukaryotic cells, the primary receptors for cAMP are the regulatory subunits of cAMP-dependent protein kinase. The crystal structure of a 1-91 deletion mutant of the type I alpha re…
Energy dispersive x ray diffraction measurements were performed on RbH to 120 GPa. RbH was observed to transform from the B2 phase to the orthorhombic, CrB, phase at 85 GPa. The equation of state for the B2 phase and the CrB phase are reported. Transmission measurements were made to 120 GPa to determine the band gap v…
The method of molecular dynamics computer simulations is employed to study oligomer melts confined in ultra-thin films and subjected to shear. The focus is on the self-diffusion of oligomers near attractive surfaces and on their desorption, together with the effects of increasing energy of adsorption and shear. It is…
Ion-beam sputtering has been used to prepare Fe/Si multilayers on a variety of substrates and over a wide range of temperatures. Small-angle x-ray diffraction and transmission electron microscopy experiments show that the layers are heavily intermixed although a composition gradient is maintained. When the spacer laye…
We present a quantitative model for Na partitioning between clinopyroxene and silicate melt, applicable in the range 0.1 MPa to 6.0 GPa, 1000–2000°C over a wide span of composition. Our model is derived from the Jadeite melting equilibrium, via the relationship Δ G ƒ( P , T ) = − RT ln K ƒ = RT ln D * Na where Δ G ƒ(…