[en] In this letter is described a TIR-total internal reflection-solar collector, with a concentration ratio of about 40-output temperature required, 250deg. The collector is made of metacrylate ''roof'' type (Amici) prisms; the engineering of the collector is described and a proper suntracking system is identified

[en] A very sensitive method for determining sodium, potassium and chlorine in very small samples of healthy and burnt human skin by neutron activation is described. Results show relevant alterations of electrolyte concentrations in burnt skin with respect to healthy skin. (author)

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[en] Measurements of the current noise power spectrum of the photoconducting insulators CdS and CdSe irradiated with monochromatic light of different wavelength λ are reported. It is shown that there is an abrupt change of about one order of magnitude in the low frequency power density of the noise when λ crosses the photoconductor gap value λ and the photocurrent and the device conductance are kept constant by varying the light intensity. The effect is explained in terms of an abrupt increase of the carrier recombination rate when the photon energy becomes larger than the energy gap of the photoconductor. Possible applications of these results are briefly discussed

[en] The quasi-elastic and inelastic spectra of 10 A neutrons scattered by MBBA in its nematic phase at various angles are reported. For small energy transfers the measured spectra have been resolved in the quasi-elastic peak, whose broadening as a function of the momentum transfer allows an evaluation of the self-diffusion coefficient, and in a broader underlying contribution due to molecular rotations. It has been found that the gas model fits very well the inelastic scattering

[en] The optical properties of conductive transparent thin films of undoped SnO², prepared by using magnetron sputtering, were studied by measuring the transmittance and the reflectance between lambda=0.25 μm and lambda=3 μm. The extracted optical constants are interpreted to give values of a direct band gap of the order of 4 eV and of an indirect band gap of the order of 3 eV. Typical SnO₂ films transmit approx. 85% of visible light, have sheet resistance R-sheet (100-800) Ω-sheet and resistivities of (2.4 10^-3-1.8 10^-2) Ω cm

[en] Two sets of a-SiC: H films were deposited by glow discharge in an Ar-SiH₄-CH₄ atmosphere to investigate the effect of a variable CH₄/SiH₄ ratio on the physical properties. The composition of the films was determined by resonant nuclear reaction and by Rutherford backscattering measurements, the optical gap and the index of refraction by transmissivity measurements in the visible-UV-NIR range, the bonding configuration by IR transmissivity measurements and the resistivity and the photoconductivity by electrical measurements in the dark and under a 500W/m² illumination. Results indicate that with increasing carbon content the refractive index decreases systematically over all wavelengths, the energy gap increases, the dark resistivity increases, the bonding configuration becomes dominated by carbon-containing chains and the structure more disordered