Materials Literature
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Acoustic emission release during tensile testing of polycrystalline aluminium is measured at room temperature. It is found that acoustic emission power and acoustic emission energy release at yielding and various strains during work- hardening increase with the inverse of the grain diameter. This dependence is explain…
The Raman spectrum of K(TCNQ) crystals has been obtained from 30 to 2300 ${\mathrm{cm}}^{\ensuremath{-}1}$. We have identified lattice modes at 70, 81, 110, 170, 229, and 295 (\ifmmode\pm\else\textpm\fi{}5) ${\mathrm{cm}}^{\ensuremath{-}1}$ and 13 intramolecular modes above 300 ${\mathrm{cm}}^{\ensuremath{-}1}$. The m…
By applying the method of symmetry breaking potential to Zwanzig's three direction model for liquid crystal, the nematic-smectic as well as isotropic-nematic transitions are investigated. Particular attention is paid to the effect of orientational fluctuation on the nematic-smectic A transition. It is shown that the n…
Previously reported spectra of nine triply ionized lanthanides in LaF3 are analyzed by using a parametrized C2 crystal-field Hamiltonian. Initial crystal-field parameters Bnm in the fitting procedure were obtained from point charge lattice sums Anm using previously derived ρn, where Bnm=ρnAnm. The largest rms deviatio…
The effect of impurities on the phase mode of CDW in a one-dimensional system is studied by taking account of the non-linearity of the problem. Most of the work is based on numerical simulations which are performed using a classical mechanical equation of motion for the phase mode. The existence of critical field for…
The Hartree–Fock instability of the SCF wave functions obtained for the quadruply bonded complexes Cr2(O2CH)4 and Mo2(O2CH)4 is studied at the ab initio level. Several cases of singlet, nonsinglet, and nonreal instabilities are found for each of these complexes at the experimental value of the metal–metal bond length.…
The intensities of plasmon-loss satellities in x-ray photoelectron (XPS) and electron-energy-loss (EEL) spectra of Mg metal have been determined. The method used has been described earlier in a similar study of aluminum. Intrinsic processes contribute 22% of the total plasmon intensity in the case of XPS core lines. T…
Abstract Red phosphorus is a highly effective flame retardant for polyolefins. The low additive levels of red phosphorus in polyethylene make it an attractive route to nonhalogen flame‐retardant systems. The mode of action of the red phosphorus has been investigated. Results indicate that the red phosphorus is effecti…
Abstract Glassy polycarbonate has been subjected to sub‐glass‐transition annealing and exposure to high‐pressure CO 2 . The subsequently measured solubilities of nitrogen, argon, and CO 2 in these specimens were found to be decreased by the former and increased by the latter. Annealing decreases the enthalpy of polyca…
The liquid-crystal alignment properties of gratings with a 1–10-μm period are described. Experiments are presented to compare the roles of interfacial interactions and surface topography in determining alignment. It is shown that grooves are neither necessary nor always sufficient to produce alignment. Interfacial for…
Antireflective (AR) coatings, which are produced from organometallic driven solutions containing oxide constituents in a chemically polymerized form, are presented. These solutions leave a film on substrates which, upon heat treatment, converts to a glasslike oxide film having the desired optical thickness and index o…
We have carried out computer simulations of the freely jointed polymer chain with an excluded volume interaction using a dynamic Monte Carlo method for chain lengths N between N=8 and N=100. The equilibrium values of end-to-end distances and radius of gyration approach the asymptotic form ∼Nν for N≳70 (scaling limit)…
High-temperature measurements have been performed on the electronically conducting oxide system ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Cr}{\mathrm{O}}_{3}$ ($0<~x<~0.4$). The electrical conductivity displayed thermally activated temperature dependence between 300 and 1900 K with activation ene…
The electrical resistivity, magnetic susceptibility and EPR of (Ti 1-x V x ) 4 O 7 single crystals (0<x<1.6 at.%) have been studied between 4.2 and 300K and the heat capacity was examined in the range 120-300K. Pure Ti 4 O 7 and the compounds with x< approximately 0.35 at.% show three phases, a low-temperature semicon…
The authors demonstrate that the order of kinetics of the TL process can change with the dose received by a sample. In LiF the order of kinetics becomes constant only when the dose given to the sample is smaller than the saturation dose by at least an order of magnitude. The order of kinetics followed by glow peaks V…
The influence of the coupling between valence and conduction bands on the scattering of electrons by acoustic phonons is investigated for the case of bismuth. The calculation is based on a model employed previously for the lead chalcogenides and InSb. Elements of the weak field thermodynamic tensor have been analysed…
The Raman spectrum of NiCl 2 has been measured at various temperatures above and below the antiferromagnetic ordering temperature T N =52.3K. Two prominent bands at 175.2 and 270.9 cm -1 (6K) were observed at all temperatures and are assigned to the E g and A 1g k=0 optic phonons, respectively. A careful search was ma…
The mechanism of ozone generation in the silent discharge of air-fed ozonisers is studied theoretically and experimentally. The nitrogen oxides (NO x ) formed in the silent discharge have been found to play an important role in the process of ozone generation due to the catalytic cycle for O 3 destruction: NO+O 3 to N…
The Raman spectra of 4-pyridine-carboxaldehyde-doped Al-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$-Ag tunnel junctions evaporated onto Ca${\mathrm{F}}_{2}$ films and optical diffraction gratings show that the molecular Raman scattering is strongly enhanced under conditions which permit the direct excitation of the surface…
Abstract Suitable chemical treatment of North Sea oil and gas production plays a small but vital role in determining the production plays a small but vital role in determining the success of the project. During the initial period of production from a new oilfield, the chemical treatment requirements are generally mini…