Materials Literature
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BaTi${\mathrm{O}}_{3}$ ceramics doped with several iron-group elements up to 2.0 mole% were identically prepared and afterwards annealed at 700\ifmmode^\circ\else\textdegree\fi{}C in ${\mathrm{O}}_{2}$ at 150 bar or in ${\mathrm{H}}_{2}$-${\mathrm{H}}_{2}$O with an oxygen partial pressure of ${10}^{\ensuremath{-}22}$…
The hydriding and dehydriding kinetics of Mg were measured by a method which sweeps through the pressure and reacted-fraction variables. However, a new data-analysis method is employed which permits the derivation of the kinetics at constant pressure, in which form they are much more amenable to interpretation. The eu…
Models based on energy and stress considerations are applied to the phenomenon of spontaneous fracture of materials due to phase transformations and thermal expansion anisotropy. Results are shown to be in reasonable agreement with observations of the grain‐size dependence of such cracking and the effects of internal…
Amorphous films with the compositions MgSiO3 and Mg2SiO4 were condensed by reactively sputtering cathodes with the compositions MgSi and Mg2Si in argon-oxygen atmospheres. Optical constants for these films in the 7-33 micron region were derived by fitting the transmission curves with harmonic oscillators (classical di…
The influence of the structure of activators on the anionic polymerisation of lactams is examined and a classification of activators taking into account the chemical nature of the active centres formed and the side products is proposed. An approach to the specific selection of activating compounds for the regulation o…
After reviewing the structural properties and formation of Al thin films on the basis of literature, the phenomena of crystal growth taking place in vacuum deposited Al films are discussed. The presence of oxygen in the residual gases affects the layer growth of the individual crystallites directly. The adsorbed oxyge…
Luminescence spectra are reported for BaMoO4. Thee emission occurs only for samples precipitated from acid solutions. Samples show at liquid helium temperature a green emission. (AIP)
The average mobility (\barµ) of majority carriers evaluated from the magneto-resistance of highly oriented graphite through B 2 /( Δ ρ/ρ 0 )=( c /\barµ) 2 +O( B 2 ) is proportional to T -1.6 between 40 K and 80 K, and T -1.2 above 80 K. The T -1.2 dependence was observed by Soule and is in agreement with the theory of…
Abstract Triplet–triplet energy transfer has been shown to occur from poly(ethylene terephthalate) (PET) units to the 2,6‐naphthalenedicarboxylate (2,6‐ND) monomer units in a series of poly(ethylene terephthalate– co –2,6‐naphthalenedicarboxylate) (PET–2,6‐ND) copolymers, as filament yarns, by an exchange mechanism at…
In this third paper of a series, the influence of phonons upon the angle-resolved spectra of electrons photoemitted from the bulk bands of solids is considered. When a tight-binding formalism is used to describe the electronic states of solids, it is possible to divide the electron-phonon interaction into terms that m…
We have measured the dielectric constants of cyanobiphenyls (CB), cyanophenylcyclohexanes (PCH), and cyanocyclohexylcyclohexanes (CCH) using a capacitance bridge with a dielectric cell having a guard ring. The ratio Δχ/Δε was also measured for these materials using a new technique which is applicable when Δχ is small…
We have detected intrinsic surface phonons in amorphous silica by performing Raman scattering and infrared-reflectivity measurements on samples of porous Vycor glass. Qualitative agreement of our experimental spectra with theoretical calculations provides an identification of the surface features in terms of microscop…
The effect of the white noise on the hydrodynamic transitions is studied in the nematic MBBA. The values of both transition points to the laminar flow and to the turbulent flow increase with the amplitude of the white noise. Brief discussion is described.
Specific-heat measurements near the nematic-smectic-$A$ transitions of the octyloxy, nonyloxy, and decyloxy members of the 4-$n$-pentyl-phenylthiol-4\ensuremath{'}-alkoxybenzoate ($\overline{n}\mathrm{S}5$) homologous series reveal the presence of critical-tricritical crossover behavior upon increasing $\overline{n}$,…
Abstract A preliminary analysis of deconvolution of a nylon model is given. This is then developed to give the available deconvolution strain in cotton. The total extension is then given by adding the fibrillar strain and is compared with experimental values of breaking extension. The relation between convolution exte…
The phase diagram of Cu 2-δ Te (δ<0.22, T <400°C) is constructed with the help of the galvanic cell Cu|CuBr|Cu 2-δ Te|C, showing that it includes as large as 10 phases in the range concerned. This diagram has been justified by DTA measurements. The electronic conductivity and ionic one are also measured.
Magnetization measurements and 55 Mn NMR study of a system with the nominal formula LaNi 1- x Mn x O 3 (0.0 ≤ x ≤0.5) were made. It was found that materials with 0.03 ≤ x ≤0.5 are mixtures of a Pauli paramagnet LaNiO 3 and a ferromagnet LaNi 0.5 Mn 0.5 O 3 . The Curie temperature of LaNi 0.5 Mn 0.5 O 3 was found to be…
Auger-electron spectroscopy (AES), low-energy-electron diffraction (LEED), electron-energy-loss spectroscopy (ELS), and ultraviolet-photoelectron spectroscopy (UPS) were used to characterize the composition, structure, and electronic properties of the strontium-titanate (100) surface and the platinum---strontium-titan…
New progress in Mie theory calculations is reported. A computer program is available using the Lentz algorithm allowing more extensive calculations, namely, studying of bigger diameters and more important absorption coefficients. Emphasis on particle sizing is considered.
A first order phase transition occurs at Ni (111) surfaces under conditions of controlled chemical potential. For a dilute Ni–C alloy of fixed bulk composition an abrupt change occurs (as temperature is lowered) in the surface carbon coverage from a very low coverage state to a two dimensional crystalline C overlayer.…