Host and defect-related luminescence in Rb 2 KTiOF 5 oxyfluoride crystals irradiated by fast electrons

The paper presents a comparative analysis of RKTF crystals (full name single crystals Rb 2 KTiOF 5 ), and RKTF + e crystals, single crystals irradiated on a cyclotron by fast electrons Rb 2 KTiOF 5 . The crystals were grown by slow solidification method. The study was conducted at a temperature from 7 to 400 K for various types of optical and radiation effects. Spectra of photoluminescence (PL) and X-ray excited luminescence (XRL) in region of 1.5-5.5 eV, time-resolved pulse cathode-luminescence (PCL) spectra, the temperature depending of the XRL, luminescence decay kinetics were studied. Single crystal RKTF are transparent from microwave up to the edge of the long-wave fundamental absorption (near UV range). We detected three luminescence bands for RKTF, in the visible spectral region, that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombinaion-type luminescence (2.1 eV) and luminescence of higher TiOF 5 complexes (1.9 eV), for all emission bands characterized by great (∼1.5-1.8 eV) Stokes shift. The exponential component with lifetime of approximately 19 μs was found in the PCL decay kinetics at 2.25 eV. In the crystal RKTF + e we detected new luminescence bands 2.6 eV and 3.2 eV and the disappearance of the RKTF luminescence bands. Stokes shift of the band 3.2 eV of the RKTF + e crystal is much smaller and is equal to 0.7 eV. Excitation of the band 3.2 eV occurs in the field of crystal transparency, which indicates the defective nature of the glow. PCL decay kinetics at 2.0 and 2.5 eV has a complex nature and consists of at least two components with a life time of 0.5 ms and 6 ms, that significantly more in comparison with RKTF. Irradiation by fast electrons of crystals Rb 2 KTiOF 5 led to entirely new optical properties and suppression of self-luminescence of the crystals. © Published under licence by IOP Publishing Ltd.This work has been partially supported by the Ministry of Education and Science of the Russian Federation – basic part of the government mandate (project No. 3.8302.2017/8.9) and Act 211 Government of the Russian Federation (contract No. 02.A03.21.0006, the Center of Excellence “Radiation and Nuclear Technologies”) and COST Action TD1401 "FAST”. The authors thank to Dr. S. Omelkov (University of Tartu, Estonia) for help in PCL experiments and M. Sarychev (UrFU) for support in low temperature measurements

Problemas y perspectivas de factorizar el desarrollo del mercado en Rusia

Under the conditions of the economic crisis and fierce competition, companies are able to efficiently use affordable financial resources such as factoring, which is a competitive business financing tool that meets international standards. The benefits of factoring can be seen in all participants of this service. It is beneficial for suppliers in terms of increasing sales, turnover, and reducing cash gaps. Due to the factoring, buyers obtain commodity loans and provide the optimal use of working capital. Commission merchants increase in their revenues and the number of customers, and strengthen their market positions. In the global market, an increase in factoring regardless of the presence or absence of a crisis leads to an increase in the volume of trade flows. In Russia, the popularity of the factoring is low compared to bank loans, especially among small and medium-sized businesses. The paper analyses the composition of the players in this market, examines the dynamics of the volumes of financing provided, the weighted average cost of factoring in comparison with the interest on loans, the number of participants, and financing by industry and region of the country. Based on an analysis of the current situation and long-term market data, the paper summarizes the problems of factoring in Russia, and identifies key factors for factoring market growth in the future.  Bajo las condiciones de la crisis económica y la feroz competencia, las empresas pueden utilizar de manera eficiente recursos financieros asequibles, como el factoring, que es una herramienta competitiva de financiación empresarial que cumple con los estándares internacionales. Los beneficios de la factorización se pueden ver en todos los participantes de este servicio. Es beneficioso para los proveedores en términos de aumentar las ventas, la rotación y reducir las brechas de efectivo. Debido al factoring, los compradores obtienen préstamos de productos básicos y proporcionan el uso óptimo del capital de trabajo. Los comerciantes de comisiones aumentan sus ingresos y el número de clientes, y fortalecen sus posiciones en el mercado. En el mercado global, un aumento en el factoring independientemente de la presencia o ausencia de una crisis conduce a un aumento en el volumen de los flujos comerciales. En Rusia, la popularidad del factoring es baja en comparación con los préstamos bancarios, especialmente entre las pequeñas y medianas empresas. El documento analiza la composición de los actores en este mercado, examina la dinámica de los volúmenes de financiamiento proporcionados, el costo promedio ponderado de factoring en comparación con los intereses de los préstamos, el número de participantes y el financiamiento por industria y región del país. . Basado en un análisis de la situación actual y datos de mercado a largo plazo, el documento resume los problemas de factoring en Rusia e identifica factores clave para factorizar el crecimiento del mercado en el futuro

Exciton Lines in Luminescence Spectra of NixZn1-xO under Inner Shell Excitation

AbstractThe paper presents the results of the study of two narrow luminescence lines I1 and I2 at the energies of 3.339 and 3.393eV respectively in NiO and solid state solution Ni0.6Zn0.4O. The luminescence spectroscopy with a sub-nanosecond time resolution upon selective photoexcitation in the energy range of absorption of the inner shells Zn M- and Ni L2,3- edges of Zn- and Ni- ions was used to promote proposed earlier mechanism of origin of luminescence lines I1 and I2. Photoluminescence decay kinetics of NiO and solid state solution Ni0.6Zn0.4O under soft x-ray excitation are discussed. The doublet of I1 and I2 lines is believed to arise due to the radiative annihilation of p-d excitons

Luminescence of Li6Gd(BO3)3 crystals upon ultraviolet and inner-shell excitations

The paper presents the results of the study on luminescence and electronic excitations in Li6Gd(BO3)3 single crystals. The optical and luminescence spectroscopy with a sub-nanosecond time resolution upon selective photoexcitation in the energy range from 3.0 to 650 eV was used to investigate in detail the luminescence of both the Gd3+ host ions and Ce3+ impurity ions as well as the processes of energy transfer between them. The intrinsic ultraviolet emission at 3.95-3.97 eV due to Pj6→S7/28 transitions in the Gd3+ host ion and the fast luminescence at 2.8-3.0 eV due to 5d→4f1 dipole-allowed transitions in the Ce3+ impurity ion were studied upon excitations through the intracenter, charge transfer, band-to-band, and inner-shell transitions. The specificity of the energy transfer upon excitation of photoluminescence in the energy range of absorption of the inner shells of different atoms of the crystal, as well as in the energy region of the giant resonance of 4d-4f transitions was revealed. On the basis of the experimental data, the bandgap Eg=9.3 eV, the minimum energy of the 5d→4 f1 and charge transfer transitions were determined. The expected positions of the ground states of the 4fn and 4fn-15d levels of trivalent lanthanide ions as well as the 4fn+1 and 4f n5d levels of divalent ions were calculated for all the lanthanide ions in Li6Gd(BO3)3 host crystal. © 2012 Elsevier B.V. All rights reserved

Theoretical and Methodological Approaches to the Supply Chain Strategies Role and Analysis of Seaport Competitiveness in the Far East of Russia

Under market conditions, competitiveness is the main quality of any subject, whether it is an enterprise or such a complex structure as a seaport. Competitiveness was considered by many authors abroad and in Russia from different positions: cost approach, innovative approach, supply chain. Each author endured a certain aspect as the main one for analysis. The article is based on the analysis of different points of view and study object features, substantiates the essence of competitiveness through an integrated approach, since the seaport, performing a complex of specific services, fights for demand at different levels: from international to intra-port. The aim of the study was the systematization of theoretical and methodological approaches to the analysis of seaport competitiveness in the Russian Far East for the further development of proposals on competitiveness improvement. Based on the analysis, they substantiated the significance of seaports in the modern world economy and the economy of the Russian Far East. They evaluated the development potential of the Far Eastern ports. On the basis of an integrated supply chain, the competitiveness of the seaports of the Far East of Russia was assessed

Spectroscopic study of red-light-emitting centers in K2Al 2B2O7: Fe single crystals

We report on spectroscopic study of red-light-emitting centers in K 2Al2B2O7 (KABO) single crystals containing ca. 2 ppm of Fe3+. Owing to the low Fe3+- concentration, KABO does not show noticeable absorption due to Fe3+ d-d-transitions in the visible spectral region, but it exhibits the charge-transfer (CT) UV-absorption bands O-Fe at 4.7, 5.7 and 6.5 eV. The red photoluminescence at 1.675 eV (FWHM = 0.173 eV) is due to intracenter 4T1 (4G) → 6A1 (6S) transitions in Fe3+ ions. Because of partial overlapping of the fundamental absorption edge of the crystal, where mobile excitons are created, and a broad CT absorption band at 6.5 eV, the most intensive red emission occurs at 7 K upon excitation in the excitonic energy region. The presence of two nonequivalent Al2O7 clusters in KABO lattice provides two different types of red-light-emitting centers in the form of Fe3+ ion occupied the Al3+ tetrahedral site. Superposition of their luminescence bands determines both the spectrum and temperature dependence of red emission in KABO at T = 7-80 K: two bands with the ratio of intensities of ca. 2:1 are 20 meV-shifted relative to each other; two-stage thermal quenching obeys the Mott law with ET = 9 and 20 meV. © 2013 Elsevier B.V. All rights reserved

Luminescence spectroscopy of K3WO3F3 oxyfluoride crystals

Spectra of photoluminescence (PL) in region of 1.5-5.5 eV, PL excitation spectra (3-22 eV), PL decay kinetics, the temperature dependence of the PL were measured for single crystals and ceramics K3WO3F3 as well as irradiate ceramics K3WO3F3. Synchrotron radiation was used for low temperature PL experiments with time resolution. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is Eg = 4.3 eV. The intrinsic luminescence of tungstates is usually ascribed to the radiative relaxation of exciton-like excitations localized on WO6 octahedra or WO4 tetrahedra. In K3WO3F3 the wide band luminescence in the region of 2.5 eV with the Stokes shift of 1.5 eV with the microsecond decay kinetics is connected with luminescence of triplet self-trapped excitons (STE). This luminescence is formed by electronic transitions in [WO3F3] octahedron. Different distortion of KWOF crystal lattice is manifested in the change of the Stokes shift of STE luminescence band. The 3.2 eV emission band in low-temperature PL spectrum with decay times of 1.8 ns and 11 ns corresponds to singlet STE luminescence. A new 2.9 eV emission band is discovered in low-temperature PL spectrum in the samples irradiated by fast electrons (E = 10 MeV, D = 160 kGy). This emission band is excited not intracenter mechanism, and through the creation of excitons bound on the defects. It is suggested that it is F-like centers of anionic sublattice induced by the mechanism of elastic collision. © 2016 Author(s)

Luminescence of Li6Y(BO3)3 doped with Pr3+ ions under x-ray, electron beam and ultraviolet excitation

This paper reports the spectroscopic properties of praseodymium-doped lithium yttrium triple borates, Li6Y(BO3)3:Pr3+(1%). Emission and photoluminescence excitation spectra were measured at room temperature in the near IR and VIS-UV range. For this Pr3+- doped triple borates, the interconfigurational 415→42 transitions with nanosecond decay time were detected. Besides the intraconfigurational 42→42 transitions in visible and near IR regions were analyzed