Materials Literature
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A model of magnetization processes is proposed which postulates the existence of two types of domain walls (resonating and relaxating) and takes into account the distribution of grain sizes in polycrystalline ferrite specimens. Mathematical expressions for approximation of magnetic spectra are obtained. The suggested…
N 2 diffuses into the structural pores of clinoptilolite 10 3 to 10 4 times faster than does CH 4 . Thus internal surfaces are kinetically selective for N 2 adsorption. Some clino samples are more effective at N 2 /CH 4 separation than others and this property was correlated with the zeolite surface cation population.…
In order to establish the atomic order (or disorder) of Li atoms in LiFe5O8, a crystallographic structure refinement and a spectroscopic Mössbauer study are made. Several polycrystalline and monocrystalline samples are separately heat treated and studied. The results are in agreement with the existence of a short-rang…
Experimental elastic moduli of the pure vitreous inorganic oxides SiO2, GeO2, P2O5, B2O3, and As2O3, are compared with simple theoretical models of elastic deformation involving the use of available estimates for the anion-cation (first order) stretching force constants. On the basis of this comparison it is concluded…
The results of a study of the atomic structure and crystallization behavior of As-Te glasses are reported. The primary tool of this investigation is M\"ossbauer-effect spectroscopy of the Te sites. Strikingly different behavior of the spectra is observed depending on whether the As content is above or below 40 at.%. I…
We present a detailed study of the Raman spectrum of $\ensuremath{\alpha}$-LiI${\mathrm{O}}_{3}$ as a function of temperature and pressure. Measurements under hydrostatic pressure were performed at 300 and 380 K. Comparison of these results among each other and with previous results from uniaxial stress measurements p…
Deep trapping of injected holes or electrons is temporarily enhanced at room temperature in chalcogenide films which have undergone prior near-band-gap photoexcitation at room temperature. Persistence of this effect can be measured by xerographic techniques which are very sensitive to relatively small changes in trapp…
Macrocyclic Complexes of Lanthanides: Stability and Electrochemical Behaviour in Methanol and Propylene Carbonate The stabilities of the 1:1 complexes of the trivalent lanthanides with the diazapolyoxamacrocycles (2.1.) and (2.2.1.) in anhydrous methanol and propylene carbonate have been determined at 25°, by competit…
The existence of dissociation plateaus in the pressure-composition isotherms for hydrogen absorption in amorphous metals is shown to depend on the degree of configurational disorder in the host lattice. Within a mean-field approximation for the attractive elastic hydrogen-hydrogen interaction, the Stoner-type conditio…
First-principles calculations on the geometric and electronic structures of undoped and doped polypyrrole chains indicate the appearance upon high doping of bipolaron states in the gap. A picture of the band-structure evolution upon doping is presented, showing the presence of bipolaron bands in the gap for experiment…
We have investigated the mechanism and driving force of the CO-induced phase transition of the Pt(100) surface. In a preceding paper, we have concentrated on the mechanism by which CO removes the surface reconstruction. As discussed, the clean reconstructed (hex) surface of Pt(100) is more stable than the unreconstruc…
Molecular dynamics has been used to study the dependence of homogeneous nucleation of the crystal on the rate with which the liquid is quenched, the initial state of the liquid and on the depth of the quench. A total of 54 simulations of quenching for a liquid rubidium system were performed and the dependence on these…
We present the results of a theoretical study of the surface electronic structure of the ideal (110), (001), and (100) faces of tin dioxide, a semiconductor crystallizing with the bulk rutile structure. The surface electronic structure is determined using a scattering-theoretic method in which the bulk electronic stru…
Electrodynamic calculations of the electric field on the surface of Ag prolate spheroids indicate that, as the size increases, the field enhancement decreases rapidly and the resonance shifts to longer wavelengths, the resonance linewidth broadens, and a new set of higher-order resonances appears. The calculated surfa…
The effect of adding 0.05 to 16.2 mol.% CeO 2 on the dielectric properties and loss tangent of sintered BaTiO 3 was investigated at different temperatures. The permittivity increased with CeO 2 additions up to 0.5 mol%, then decreased with increasing concentrations. In the samples doped with 5.6 and 16.2 mol.% CeO 2 t…
Proton mobility has been established in solid hydrazine sulphate through coulometric, conductivity, IR, DSC and TGA studies. The electrical conductivity has been measured on pressed pellets in the frequency range from 100 Hz to 100 kHz in the temperature range 300-500K. The frequency dependence of the conductivity has…
A detailed procedure leading to the evaluation of the explicit anharmonic contributions to the phonon frequency shift and the linewidth to the lowest order is described for a molecular crystal. An application is then made to obtain numerical results for phonon frequency shifts and the linewidths in deuterated naphthal…
Elastomer-modified epoxy resins have grown in usage in the past 15 years in several application areas connected with structural adhesives, composites, civil engineering/construction, electrical laminates/encapsulants and corrosion resistance. Some of this increased attention has come about through utility of telecheli…
Novel elastomeric polysiloxane modifiers for epoxy networks have been synthesized and characterized. In addition, curing studies of conventional epoxy resins incorporating these oligomers have been conducted. Structures were prepared having either epoxide, primary amine and/or secondary amine endgroups. The polymeriza…
A correlated study of the structural, optical, magnetic, and transport properties of polyacetylene, doped with iodine to nearly the metallic doping levels, shows that essentially all charges go into solitonlike states. The measurements are in quantitative agreement with charge transport via variable-range hopping amon…