Materials Literature
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Inelastic scattering of electrons by small metal particles is investigated with full inclusion of spatial dispersion effects. In sharp contrast to results obtained from classical studies, based on the use of a local dielectric constant, the differential cross section for larger collection angles is rather diffuse beca…
The frequency and temperature dependence of the elastic moduli of a number of commercially available polymers has been studied in the temperature range of 0–35 °C and for frequencies 102–106 Hz. Away from transitions a significant new relationship has been obtained, i.e., the Young’s modulus of these polymers is propo…
The luminescence spectrum of ${\mathrm{SrTiO}}_{3}$ from 1.6 to 3.2 eV has been studied as a function of time elapsed after excitation. A broad emission band with maximum intensity at 2.44 eV can be observed. The shape of this band, including some fine structure, can be reproduced by the Huang-Rhys model for excitatio…
It has been found that the dielectric capacitance response of doped silica glasses measured in the frequency range 10 -3 -10 5 Hz for temperatures between 500 and 1100K displays anomalous thermally activated resonance-type behaviour. This response is linked to time domain oscillations reported in similar materials. It…
The adequacy of the Callaway integral (1959, 1974) and the Leibfried-Schlomann formula (1979) for describing the pressure dependence of the thermal conductivity of insulators is investigated. It is concluded that, overall, the Leibfried-Schlomann formula and the Callaway integral offer roughly the same agreement betwe…
The electronic properties of the ferrous ion in (Fe(H 2 O) 6 )(NH 4 ) 2 (SO 4 ) 2 are investigated using far-infrared (FIR) Fourier transform spectra and FIR EPR measurements at low temperatures in the energy range from 8 to 100 cm -1 . Several absorption lines can be identified to originate from electronic excitation…
Polarised luminescence spectra of Cr 3+ -doped beta -alumina crystals were taken at temperatures between 78 and 295K. From luminescence excitation spectra the energy level scheme of the Cr 3+ ion is obtained. This turns out to be very similar to that of ruby, with the Cr 3+ ion substitutional for the Al 3+ ion in the…
Neutron and X-ray diffraction measurements of liquid sulphuric acid are reported. The aim of the present work is to study the arrangement of the hydrogen atoms in the liquid in comparison with the solid phase. By employing both experimental techniques, the localization of both heavy atoms and hydrogen is possible. We…
The electronic structure of ferroelectric LiNbO 3 at room temperature has been investigated using the X alpha molecular orbital method applied to a NbO 6 cluster of C 3v symmetry. The total and partial densities of states associated to the O 2p valence band built up from the X alpha eigenvalues are compared with XPS a…
Intense luminescence due to the 2 F 5/2→2 F 7/2 transition, near 1μm, is observed when the elpasolites Cs2NaHoCl6 and Cs2NaNdCl6 are doped with Yb3+ and excited by 488 nm or 514 nm argon ion laser radiation respectively. The mechanism of energy transfer has been studied for Cs2NaHoCl6: YbCl3- 6 using temperature, conc…
Layer-by-layer alternating surface reconstructions of Si(001) 2×1 and 1×2 have been observed for the first time using reflection high-energy electron diffraction (RHEED) during molecular beam epitaxy. RHEED intensity oscillations of the specular beam and two kinds of reconstruction related spots have been monitored si…
$^{129}\mathrm{I}$ M\"ossbauer spectra of $g\ensuremath{-}{\mathrm{Ge}}_{x}{\mathrm{Se}}_{1\ensuremath{-}x}$ alloys display a local maximum in the site-intensity ratio $\frac{{I}_{B}}{{I}_{A}}(x)$ at the critical composition $x={x}_{c}=0.23\ifmmode\pm\else\textpm\fi{}0.02$. This observation is consistent with the real…
The dependence of the nonequilibrium partition coefficient $k$ of Bi in Si upon solidification velocity $v$ has been measured with sufficient accuracy to distinguish between proposed solute-trapping mechanisms. For the range of measured velocities, 2-14 m/s, we observe a much more gradual increase in $k$ with increasi…
The substitution of hydroxyproline for proline in position Y of the repeating Gly-X-Y tripeptide sequence of collagen-like poly(tripeptide)s (i.e., in the position in which Hyp occurs naturally) is predicted to enhance the stability of aggregates of triple helices, while the substitution of Hyp in position X (where no…
While MnTe has the stable NiAs structure with a direct band gap of 1.30 eV and a Mn-Te bond length of 2.92 \AA{}, extrapolation of the data for the zinc-blende alloy ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Te}$ to $x=1$ suggests an alloy-stabilized MnTe phase with very different properties: a band ga…
(4 ,000-1 0,000), urea nitrogen (BUN) 22 mg/dl (8-20), creatinine 1.9 mg/dl (0 .5-1 .0) , and uric acid > 12 mg/dl (2.7-7.8). Bilirubin was 1.4 mg/dl (0 .1-0.9) and SGOT, LDH , and alkaline phosphatase were elevated. Serum osmolality was 330 mosmoles/kg (269-298), while
Alloying additions of 0.25–1.0 wt‐% B to austenitic manganese steels lead to the formation of carboborides arranged in a cell‐type microstructure. Pin abrasion tests on flint grinding paper using different dead weight loads reveal that these carboborides do not substantially improve the wear resistance due to a relati…
Article Untersuchungen zum Aufbau von interferenzfähigen Deckschichten auf gaskontrastiertem HfC-Co-Hartmetall / Investigations about the Structure of Interference Coatings on Gas-Contrasted HfC-Co Hard Metal was published on June 1, 1986 in the journal Practical Metallography (volume 23, issue 6).
Abstract Kinetic and equilibrium measurements were carried out for the complexation reaction of nickel(II) malate and nickel(II) tartrate in an aqueous solution at 20 °C and at pressures up to 100 MPa. From the pressure dependence of the stability constant and the rate constant, the reaction volume, ΔV0, and the activ…
The structures of glasses in the system CuO‐PbO‐SiO 2 have been investigated by Raman and Fourier transform infrared (FTIR) spectroscopy. Glasses of compositions represented by 2 x CuO.(1 – x) PbO.(l – x)SiO 2 (x = 0 to 0.1) and 3 x CuO.(l – x)PbO.2(l – x)SiO 2 (x=0 to 0.1) may contain up to 2 and 4 mol% CuO, respecti…