Materials Literature
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We derive a formula, useful for first-principles calculations, which relates the free energy of an oxide/metal interface to the free energies of surfaces and the work of separation of the interface. We distinguish the latter {\it mechanical} quantity from the {\it thermodynamic} work of adhesion, and we describe expli…
A review of the approximations in any time-dependent density functional calculation of excitation energies is given. The single-pole approximation for the susceptibility is used to understand errors in popular approximations for the exchange-correlation kernel. A new hybrid of exact exchange and adiabatic local densit…
In seeking to understand at a microscopic level the response of dislocations to stress we have undertaken to study as completely as possible the simplest case: a single dislocation in a two dimensional crystal. The intention is that results from this study will be used as input parameters in larger length scale simula…
The role of the exchange-correlation potential and the exchange-correlation kernel in the calculation of excitation energues from time-dependent density functional theory is studied. Excitation energies of the He and Be atoms are calculated, both from the exact ground-state Kohn-Sham potential, and from two orbital-de…
A scheme for making ab-initio calculations of the dynamic paramagnetic spin susceptibilities of solids at finite temperatures is described. It is based on Time-Dependent Density Functional Theory and employs an electronic multiple scattering formalism. Incommensurate and commensurate anti-ferromagnetic spin fluctuatio…
A simple description of thermodynamics of DMAAS and DMAGaS ferroelectric crystals by means of Landau expansion is proposed. Conditions of occurrence of phase transitions are established and their temperatures are obtained. The influence of external hydrostatic pressure on phase transitions is described. The temperatur…
This paper demonstrates that, by using oil-in-water micelles, nonstoichiometric zinc ferrite nanoparticles are fabricated. Control in size and composition is obtained. The nanocrystals are characterized by a spinel structure with two sublattices in tetrahedral and octahedral sites. Repartition of Fe 3+ in the two subl…
The elastic moduli of polymerically stabilized suspensions consisting of colloidal silica particles coated with endgrafted PDMS ( M n = 80 000) in heptane, were measured as a function of concentration. And the elastic modulus at high frequency was quantitatively described by model calculations with microscopic paramet…
The intensity maxima of lamellar reflections in small-angle scattering patterns from uniaxially oriented polymers such as fibers do not generally fall on a straight layer line or on a circular arc. The shape of the reflection can be analyzed by measuring the periodicity L φ of the lamellar planes as a function of the…
A combined microcalorimetry and adsorption study has been used to characterize the surface acidity of two series of MCM-41 aluminosilicates (referred to as SiAl x C n, where x is the mole Si:Al ratio and n the chain length of the surfactant template). 29 Si magic angle spinning NMR spectra of a selected sample (SiAl32…
[reaction: see text] The formal synthesis of the ocular age pigment A2-E was achieved by the efficient one-pot preparation of the substituted pyridine, which involves the aza-6pi-electrocyclization of the Schiff base derived from (E)-3-carbonyl-2,4,6-trienal followed by oxidation.
With the help of a Si(Li) detector, incoherent scattering cross sections of Ag, In and Sn were determined from 40°-135° in the case of 59.54 keV gamma rays of Am-241. A new method has been developed to determine differential incoherent scattering cross sections of elements. This method is based on simultaneous measure…
A method of obtaining polymer with markedly decreased entanglements concentration in melt, via high-pressure crystallization of high-density polyethylene (HDPE), is elaborated. It is shown, by calculations and experiments, that melting of chain-extended crystals obtained in this process provides a chain-disentangled m…
Spider dragline silk is Nature's high-performance protein fiber. This biomaterial has attracted much interest from scientists in various disciplines since it has become feasible to produce spider silk proteins by means of biotechnology. This article reports on research directed toward the regeneration of spider silk.…
We present a model calculation for the temperature dependent behaviour of surface states on a ferromagnetic local-moment film. The film is described within the s-f model featuring local magnetic moments being exchange coupled to the itinerant conduction electrons. The surface states are generated by modifying the hopp…
We use Monte-Carlo simulations to study island formation in the growth of thin semiconducting films deposited on lattice-mismatched substrates. It is known that islands nucleate with critical nuclei of about one atom and grow two dimensionally until they reach a critical size s$_c$, when it is favorable for the island…
A comprehensive theoretical and experimental study is presented of the magnetic susceptibility versus temperature χ(T) of spin S = 1/2 two- and three-leg Heisenberg ladders and ladder oxide compounds. Extensive quantum Monte Carlo simulations of χ(T) were carried out for both isolated and coupled two-leg ladders with…
Polyelectrolytes in poor solvents show a necklace structure where collapsed polymer pearls are linked to stretched strings. In the present paper the elasticity of such chains is studied in detail. Different deformation regimes are addressed. The first is the continuous regime, where many pearls are present. A continuo…
The physical and chemical properties of nanophase materials rely on their crystal and surface structures. Transmission electron microscopy (TEM) is a powerful and unique technique for structure characterization. The most important application of TEM is the atomic-resolution real-space imaging of nanoparticles. This ar…
The light deflection phenomenon is studied in ammonium pentafluoro antimonate (APFA) crystals versus the laser beam incidence related to the twinned sample. The variations of the orientation of the deflected beams, as well as of their polarization are measured and theoretically explained. A simplified model allows one…