Radiation Induced Enhancement of Hydrogen Influence on Luminescent Properties of nc-Si/SiO Structures.

Using photo-luminescence, infrared spectroscopy, and electron spin resonance technique, the silicon dioxide films with embedded silicon nanocrystals (nc-Si/SiO structures) have been investigated after γ-irradiation with the dose 2 × 10 rad and subsequent annealing at 450 °C in hydrogen ambient. For the first time, it was shown that such a radiation-thermal treatment results in significant increase of the luminescence intensity, in a red shift of the photoluminescence spectra, and in disappearance of the electron-spin resonance signal related to silicon broken bonds. This effect has been explained by passivation of silicon broken bonds at the nc-Si-SiO interface with hydrogen and by generation of new luminescence centers, these centers being created at elevated temperatures due to transformation of radiation-induced defects.

[Densitometric parameters in the presence of risk factors and complications of osteoporosis].

The paper deals with the densitometric study of 3000 persons due to 21 to 85 years. It presents the major common risk factors of osteoporosis and osteopenia and the indices of bone mineral density in relation to age, risk factors, and a history of bone fractures. Groups of the examinees were formed according to the history and densitometric data.