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Papers by Alexander Kozhevin
<jats:p>The active component of chromia-alumina dehydrogenation catalysts has been studied ... more <jats:p>The active component of chromia-alumina dehydrogenation catalysts has been studied by Raman and photoluminescence spectroscopy. The stress state at the Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> interface has been determined by photoluminescence spectroscopy. A model...</jats:p>
Glass and Ceramics, 2017
The luminescence spectra in samples of fired kaolin are investigated. It is shown that the obtain... more The luminescence spectra in samples of fired kaolin are investigated. It is shown that the obtained radiation corresponds to the luminescence of Cr3+ ions in mullite. The effect of the firing temperature and mass content of chromium oxide on the emission spectra is studied. The activation energy of mullite formation is determined from the experimental dependences to be Ea = 144 ± 6 kJ/mole and the maximum solubility of Cr2O3 in mullite equals 0.33%.
Journal of Russian …, 2007
Page 1. Journal of Russian Laser Research, Volume 28, Number 1, 2007 LASER SPECTROSCOPY OF NANOCR... more Page 1. Journal of Russian Laser Research, Volume 28, Number 1, 2007 LASER SPECTROSCOPY OF NANOCRYSTALS OF ALUMINUM AND SILICON OXIDES VS Gorelik,1 AE Kozhevin,2 SN Mikov,2 PP Sverbil',1 and MM Stepanov2 1P. ...
Physica Status Solidi (a), 2000
The photoluminescence spectra of Al 2 O 3 : Cr 3 nanopowder under excitation by a frequencydouble... more The photoluminescence spectra of Al 2 O 3 : Cr 3 nanopowder under excitation by a frequencydoubled YAG:Nd laser (l ex 532 nm) and a nitrogen-vapour pulsed laser (l ex 337:1 nm) have been studied. A considerable difference between the spectra of nanocrystalline and macrocrystalline samples has been observed. The nanocrystalline samples reveal a broad asymmetric line with the maximum at 690 nm under the YAG : Nd excitation, whereas under the nitrogen-vapour laser excitation, the broad line becomes more symmetric, and its maximum shifts by 45 nm to the longer-wavelength region. The above shift is shown to be due to a drastic change in the Huang-Rhys parameter of the 2 E± 4 A 2 transition. A decay of the broad line with the increase of the duration of UV illumination has been observed.
<jats:p>The active component of chromia-alumina dehydrogenation catalysts has been studied ... more <jats:p>The active component of chromia-alumina dehydrogenation catalysts has been studied by Raman and photoluminescence spectroscopy. The stress state at the Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> interface has been determined by photoluminescence spectroscopy. A model...</jats:p>
Glass and Ceramics, 2017
The luminescence spectra in samples of fired kaolin are investigated. It is shown that the obtain... more The luminescence spectra in samples of fired kaolin are investigated. It is shown that the obtained radiation corresponds to the luminescence of Cr3+ ions in mullite. The effect of the firing temperature and mass content of chromium oxide on the emission spectra is studied. The activation energy of mullite formation is determined from the experimental dependences to be Ea = 144 ± 6 kJ/mole and the maximum solubility of Cr2O3 in mullite equals 0.33%.
Journal of Russian …, 2007
Page 1. Journal of Russian Laser Research, Volume 28, Number 1, 2007 LASER SPECTROSCOPY OF NANOCR... more Page 1. Journal of Russian Laser Research, Volume 28, Number 1, 2007 LASER SPECTROSCOPY OF NANOCRYSTALS OF ALUMINUM AND SILICON OXIDES VS Gorelik,1 AE Kozhevin,2 SN Mikov,2 PP Sverbil',1 and MM Stepanov2 1P. ...
Physica Status Solidi (a), 2000
The photoluminescence spectra of Al 2 O 3 : Cr 3 nanopowder under excitation by a frequencydouble... more The photoluminescence spectra of Al 2 O 3 : Cr 3 nanopowder under excitation by a frequencydoubled YAG:Nd laser (l ex 532 nm) and a nitrogen-vapour pulsed laser (l ex 337:1 nm) have been studied. A considerable difference between the spectra of nanocrystalline and macrocrystalline samples has been observed. The nanocrystalline samples reveal a broad asymmetric line with the maximum at 690 nm under the YAG : Nd excitation, whereas under the nitrogen-vapour laser excitation, the broad line becomes more symmetric, and its maximum shifts by 45 nm to the longer-wavelength region. The above shift is shown to be due to a drastic change in the Huang-Rhys parameter of the 2 E± 4 A 2 transition. A decay of the broad line with the increase of the duration of UV illumination has been observed.