152 research outputs found
Computer simulation of the photoluminescence of nanostructured aluminum oxide excited with pulsed synchrotron radiation
An algorithm and a program are developed to calculate the photoluminescence (PL) parameters for bulk single-crystal and nanoscale dielectrics excited with pulsed synchrotron radiation. The luminescence spectra of F and F+centers and the PL decay kinetics in single-crystal and nanoscale aluminum-oxide samples containing oxygen anion vacancies are calculated for various nanoparticle sizes. It is shown that a noticeable broadening of the bands and a decrease in the afterglow time is observed for nanoparticle sizes that are less than 20 nm. Β© 2013 Pleiades Publishing, Ltd
Dosimetric application of green luminescence in irradiated TLD-500 detectors
The spectral and kinetic characteristics of thermoluminescence (TL) for anion-defective Ξ±-Al2O3 single crystals in the 4.4-2.2 eV range at 300-600 K were studied. Three-dimensional (3D) plots of the luminescence under research for a sample before and after UV irradiation at 623 K for 30 min were analyzed. The increase in the emission response in the 2.4 and 3.7 eV bands for the sample after the photothermal treatment was observed. The dominant contribution of a thermally stimulated process with first-order kinetics in the regularities of the 2.4 eV luminescence was shown. The linearity of the dose dependences for the 2.4 eV TL response in different samples at 10-5-1 Gy was demonstrated. The advantage of using the green thermoluminescence in the TLD-500 for solid state dosimetry was discussed. Β© 2013 Elsevier B.V. All rights reserved
X-ray fluoresced high-Z (up to Z = 82) K-x-rays produced by LiNbO3 and LiTaO3 pyroelectric crystal electron accelerators
High-energy bremsstrahlung and K X-rays were used to produce nearly
background-free K X-ray spectra of up to 87 keV (Pb) via X-ray fluorescence.
The fluorescing radiation was produced by electron accelerators, consisting of
heated and cooled cylindrical LiTaO3 and LiNbO3 crystals at mTorr pressures.
The newly discovered process of gas amplification whereby the ambient gas
pressure is optimized to maximize the electron energy was used to produce
energetic electrons which when incident on a W/Bi target gave rise to a
radiation field consisting of high-energy bremsstrahlung as well as W and Bi K
X-rays. These photons were used to fluoresce Ta and Pb K X-rays.Comment: 6 pages, 6 figures, PD
The role of deep centers in formation of luminescent and dosimetric properties of wide-gap materials
Luminescent and dosimetric properties of nanostructured ceramics based on aluminum oxide
The main features of thermoluminescence (TL) of nanostructured ceramics based on anion-defective aluminum oxide have been investigated. The kinetic parameters of the TL dosimetric peak at 475 K have been determined. The possibility of using nanostructured ceramics for beta-radiation dosimetry of high doses (up to 1 kGy) with thermoluminescence of deep traps has been justified. It has been found that the light sum of the dosimetric peak decreases with an increase in the heating rate due to the temperature quenching of the luminescence. The obtained results have confirmed that the mechanism of TL quenching in anion-defective aluminum oxide is associated with the temperature dependence of the probability of the capture in deep traps, which can be caused by thermal ionization of excited states of F-centers. Β© 2013 Pleiades Publishing, Ltd
Disintegration of microcrystalline Zn2SiO4:Mn phosphor powder
Zn2SiO4:Mn (willemite) nanoparticles βΌ30 nm in size have been prepared by disintegrating microcrystalline willemite powder in a planetary ball mill. X-ray diffraction and scanning electron micros-copy characterization showed that ball milling of the Zn2SiO 4:Mn powder for 60 min or a longer time ensured complete disintegration of the microcrystalline material and that the crystal structure of the resultant nanoparticles was identical to that of the parent powder. Β© 2013 Pleiades Publishing, Ltd
Cooperation Model of Interaction Between the University and Industrial Enterprises
ΠΠ°ΡΡΠΎΡΡΠ°Ρ ΡΠ°Π±ΠΎΡΠ° ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π° ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ΅ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ΠΎΠ² ΠΊ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠΎΠ² Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ ΡΠ½ΠΈΠ²Π΅ΡΡΠΈΡΠ΅ΡΠΎΠ² Ρ ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΡΠΌΠΈ ΡΠ΅Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ΅ΠΊΡΠΎΡΠ° ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΊΠΈ Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ
Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΠΈ Π΄ΠΎΡΡΠΈΠΆΠ΅Π½ΠΈΡ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΡΠ²Π΅ΡΠ΅Π½ΠΈΡΠ΅ΡΠ° Π Π€. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Π° ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΡΡΠΎΠ²Π½Π΅ΠΉ ΠΈ ΡΠΈΠΏΠΎΠ² Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ, ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ ΠΌΠΎΠ΄Π΅Π»ΠΈ ΡΡΡΠ°ΡΠ΅Π³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΠ°ΡΡΠ½Π΅ΡΡΡΠ²Π° Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ ΡΠΎΠ²ΠΌΠ΅ΡΡΠ½ΠΎΠΉ ΠΈΠ½Π½ΠΎΠ²Π°ΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΡ ΠΏΠΎΠ»Π½ΠΎΠ³ΠΎ ΡΠΈΠΊΠ»Π°. Π ΡΠ°ΠΌΠΊΠ°Ρ
ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π½ΠΎΠΉ ΠΌΠΎΠ΄Π΅Π»ΠΈ ΠΎΠ±ΡΡΠΆΠ΄Π°ΡΡΡΡ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΡΡΠ°Π½ΡΡΠ΅ΡΠ° ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΉ.This work is devoted to the development of approaches to the formation of mechanisms for interaction between universities and organizations in the real sector of the economy in the context of the need to achieve technological sovereignty of the Russian Federation. A classification of levels and types of interaction is presented, and models of strategic partnership based on the creation of a full-cycle joint innovation infrastructure are considered. Within the framework of the proposed model, the features of technology transfer mechanisms are discussed
ANISOTROPY OF EXOEMISSION PROPERTIES OF QUARTZ SINGLE-CRYSTALS
The symmetrical aspects of exoelectron emission in quantz are discussed. The dependence of the emission intensity and the energy spectra on the emitting direction show that the anisotropy of the emission properties of quartz is determined by the point-symmetry group of a crystal. It is also shown that the absence of a symmetry center in a quartz lattice changes the charge distribution of the emission-active layer upon heating. TSEE related to piezoelectric polarization along certain crystallographic directions was obtained.
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