Rietveld refinement for indium nitride in the 105-295 K range

Results of Rietveld refinement for indium nitride data collected in the temperature range 105-295 K are presented. Acicular microcrystals of indium nitride prepared by reaction of liquid indium with nitrogen plasma were studied by X-ray diffraction. The diffraction measurements were carried out at the Swiss-Norwegian Beamline SNBL (ESRF) using a MAR345 image-plate detector. Excellent counting statistics allowed for refinement of the lattice parameters of InN as well as those of the metallic indium secondary phase. In the studied temperature range, the InN lattice parameters show a smooth increase that can be approximated by a linear function. Lattice-parameter dependencies confirm the trends indicated earlier by data measured using a conventional equipment. The relative change of both the a and c lattice parameters with increasing the temperature in the studied range is about 0.05%. The axial ratio slightly decreases with rising temperature. The experimental value of the free structural parameter, u=0.3769(14), is reported for InN for the first time. Its temperature variation is found to be considerably smaller than the experimental error. The thermal-expansion coefficients (TECs), derived from the linearly approximated lattice-parameter dependencies, are αa=3.09(14)×10−6 K−1 and αc=2.79(16)×10−6 K−1. The evaluated TECs are generally consistent with the earlier data. For the present dataset, the accuracy is apparently higher for both, the lattice parameters and thermal-expansion coefficients, than for the earlier results. The refined lattice parameter cIn of the indium secondary phase exhibits the known strongly nonlinear behavior; a shift (ΔT equal about −50 K) of the maximum in cIn(T) dependence is observed with respect to the literature dat

Жизнь и труд незрячих людей в древних веках

У статті представлений огляд питань життя і можливостей працевлаштування людей з дисфункцією зору на підставі обраної літератури. Період дослідження охоплює епохи починаючи з доісторичної до пізнього Середньовіччя.The article presents an overview of the issues of life and employment opportunities of people with dysfunction of view on the basis of selected literature. The study period covers the era from prehistoric to late Medieval times.В статье представлен обзор вопросов жизни и возможностей трудоустройства людей с дисфункцией зрения на основании избранной литературы. Период исследования охватывает эпохи начиная с доисторической до позднего Средневековья

Lattice parameter of polycrystalline diamond in the low-temperature range

The lattice parameter for polycrystalline diamond is determined as a function of temperature in the 4–300 K temperature range. In the range studied, the lattice parameter, expressed in angstrom units, of the studied sample increases according to the equation a = 3.566810(12) + 6.37(41) × 10−14T 4 (approximately, from 3.5668 to 3.5673 Å). This increase is larger than that earlier reported for pure single crystals. The observed dependence and the resulting thermal expansion coefficient are discussed on the basis of literature data reported for diamond single crystals and polycrystal

Driver reaction to navigation instructions incorporating good and poor landmarks

The study consisted of a road-based trial involving 48 participants using a navigation system to complete a complex urban route. The participants were divided into three matched groups experiencing one of the following landmark conditions: good, poor or no landmarks, incorporated in verbal instructions. A range of objective and subjective measures were taken to assess driver performance with and attitudes to each of the landmark categories. The aims were to: • assess the impact on driver performance and attitudes of presenting navigation instructions which included good, poor or no landmarks • validate the REGIONAL model, which was developed to predict the navigational value of individual landmarks • identify any other factors (e.g. driver or manoeuvre characteristics) that may affect the value of landmark

Near-forward Raman scattering by bulk and surface phonon-polaritons in the model percolation-type ZnBeSe alloy

We study the bulk and surface phonon-polaritons of the Zn0.67Be0.33Se zincblende alloy by near-forward Raman scattering. The short (Be-Se) bond exhibits a distinct percolation doublet in the conventional backscattering Raman spectra, corresponding to a three-mode behavior in total [1(Zn-Se),2(Be-Se)] for Zn0.67Be0.33Se. This offers an opportunity to achieve a refined understanding of the phonon-polariton modes of a zincblende alloy beyond the current two-mode approximation, corresponding to a [1(Zn-Se),1(Be-Se)] description in the present case. The discussion is supported by contour modeling of the Raman signals of the multi-mode bulk and surface phonon-polaritons within the formalism of the linear dielectric response