Materials Literature
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Following the recent discussion on the puzzling nature of the interactions in the nanotubular system Na2V3O7, we present a detailed ab-initio microscopic analysis of its electronic and magnetic properties. By means of a non-trivial downfolding study we propose an effective model in terms of tubes of nine-site rings wi…
A protein conformation transition from random coil and/or helical conformation to beta-sheet is known to be central to the process used by silk-spinning spiders and insects to convert concentrated protein solutions to tough insoluble threads. Several factors including pH, metallic ions, shear force, and/or elongationa…
Magnesium alanate $\mathrm{Mg}{(\mathrm{Al}{\mathrm{H}}_{4})}_{2}$ has recently raised interest as a potential material for hydrogen storage. We apply ab initio calculations to characterize structural, electronic and energetic properties of $\mathrm{Mg}{(\mathrm{Al}{\mathrm{H}}_{4})}_{2}$. Density functional theory ca…
Alkali halide (100) crystal surfaces are anomalous, being very poorly wetted by their own melt at the triple point. We present extensive simulations for NaCl, followed by calculations of the solid-vapor, solid-liquid, and liquid-vapor free energies showing that solid NaCl(100) is a nonmelting surface, and that its ful…
This study deals with the spin wave spectrum in magnetic macrostructure (composed of two ferromagnetic materials) showing a 3D periodicity: spherical ferromagnetic grains disposed in the nodes of a simple cubic crystal lattice are embedded in a matrix with different ferromagnetic properties. It is shown that the \text…
In this paper we present a theoretical analysis of the effect of anomalies of the Fermi surface (FS) curvature on oscillations in the electron density of states (DOS) in strong magnetic fields. It is shown that the oscillations could be significantly strengthened when the FS curvature turns zero in the vicinities of s…
The thermal depoling behavior of several different Aurivillius phase ferroelectric ceramics has been studied. This includes two-layer (CaBi2Nb2O9,Ca0.9Ba0.1Bi2Nb2O9,Bi3NbTiO9,Bi3Nb1.2Ti0.8O9), three-layer (Bi4Ti3O12), and four-layer [CaBi4Ti4O15,Ca0.94(Na,Ce)0.03Bi4Ti4O15] compounds. All of them have a high Curie poin…
Spectra of one-particle and collective excitations in narrow-band ferromagnets with unquenched orbital moments are calculated in various theoretical models. The interaction of spin and orbital excitations with conduction electrons results in the damping of the former which, however, turns out to be rather small; there…
In the summary the results of experimental research of the dispersed media dielectric properties /spl epsiv/ and tg/spl delta/, in wide microwave band 2.5-3.5, 5.6-8.3 and 8-12 GHz, as a specimens of water foam, which are located in sections of rectangular waveguides are presented. The characteristics of absorption an…
Stress migration (SM) reliability of wide copper (Cu) interconnects with gouging vias was studied using a via chain structure stressed at temperatures ranging from 150/spl deg/C to 200/spl deg/C. After a 1000-hour SM test, via chain structures at the edge of the wafer were observed to have extremely high resistance du…
The use of hydrogel beads for the crystallization of proteins is explored in this contribution. The dynamic behaviour of the internal precipitant, protein concentration and relative supersaturation in a gel bead upon submerging the bead in a precipitant solution is characterized theoretically using a transient diffusi…
The specific heat and the thermal expansion under ambient pressure and the temperature dependence of magnetic susceptibility under applied pressure have been investigated for $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Mn}}_{1\ensuremath{-}x}{M}_{x}$ ($M=\mathrm{Ru}$, Os, and Ir) alloys by taking spin fluctuation…
Octupolar molecules are generally believed to be of potential use in developing nonlinear optical materials owing to the fact that they do not easily form molecular aggregates. This is often put against the conjectured drawback that electric fields have no poling, or ordering, effect for this class of molecules becaus…
Abstract Phenoxymethylpenicillin (PMP) has been reversibly intercalated into a layered double hydroxide, and the resulting composite exhibits effective anti‐bacterial activity. Powder X‐ray diffraction studies indicate that the PMP molecules are interdigitated between the inorganic layers, and under mild acidic media,…
The most challenging requirement for depositing NiTi-based shape memory thin films is the control of film composition because a small deviation can strongly shift the transformation temperatures. This article presents a technique to control film composition via adjustment of the power supplied to the targets during si…
A new spectroscopic cell has been designed for studying model catalysts using in situ or operando X-ray absorption spectroscopy. The setup allows gas treatment and can be used between 100 and 870 K. Pressures from 10(-3) Pa up to 300 kPa can be applied. Measurements on model systems in this particular pressure range a…
Electrolytic deposition is used to prepare submicrometer-sized vaterite (CaCO3) tubes (see Figure) in the absence of organic molecules, the presence of which was previously thought to be necessary for the growth of calcium carbonate crystals in complex morphologies. The mechanism of formation is shown experimentally t…
Hydrogen permeability (Φ), i.e., the product of hydrogen diffusion coefficient (D) and hydrogen solubility (K), of the as-cast Nb40Zr30Ni30 (mol %) alloy has been investigated. This alloy is composed of the primary body-centered-cubic (bcc)-(Nb, Zr) and eutectic {(Nb,Zr)+ZrNi} phase and the chemical composition and th…
A new X-ray absorption cell dedicated to in situ and operando experiments in heterogeneous catalysis has been built and tested. The cell consists of several boron nitride and stainless steel plates linked together using graphite seals. It allows the measurement of XANES and EXAFS spectra of heterogeneous catalysts wit…
The interface effect of InSb quantum dots (QDs) embedded in $\mathrm{Si}{\mathrm{O}}_{2}$ matrix has been investigated by Raman scattering spectroscopy, x-ray diffraction (XRD), and x-ray absorption fine structure (both of EXAFS and XANES). The EXAFS and XRD results show clearly that the bond length of the Sb-In first…