Категорія двоїни і становлення морфологічної норми української мови

У статті простежено вплив граматичної категорії двоїни на становлення морфологічної норми сучасної української літературної мови.The research presents an analysis of grammatical category of plural number with pair meaning. The main trends of morphological norm in literary Ukrainian have been generalised

Low Temperature Precursor Route for Highly Efficient Spherically Shaped LED-Phosphors M2Si5N8:Eu2+ (M = Eu, Sr, Ba)

The highly efficient nitridosilicate phosphors M2Si5N8 (M = Sr, Ba, Eu) for phosphor-converted pc-LEDs were synthesized at low temperatures using a novel precursor route involving metal amides M(NH2)2. These precursors have been synthesized by dissolution of the respective metals in supercritical ammonia at 150°C and 300 bar. The thermal behavior and decomposition process of the amides were investigated with temperature programmed powder X-ray diffractometry and thermoanalytical measurements (DTA/TG). These investigations rendered the amides as suitable intermediates for reaction with silicon diimide (Si(NH)2). Thus, the desired nitridosilicate phosphors were obtained at relatively low temperatures around 1150−1400°C which is approximately 300°C lower compared to common synthetic approaches starting from metals or oxides. The influence of the thermal treatment on the phosphor morphology has been studied extensively. The accessibility of spherical phosphor particles represents another striking feature of this route since it improves light extraction from the crystallites due to decreasing light guiding and decreasing re-absorption inside the phosphor particle. The synthesized luminescent materials M2Si5N8:Eu2+ (M = Sr, Ba) exhibit quantum efficiencies and emission band widths (FWHM 70−90 nm) comparable to standard phosphor powders. Employment of Eu(NH2)2 as dopant reagent for synthesis of Ba2Si5N8:Eu2+ proved favorable for the formation of spherical crystallites compared to doping with Eu metal, halides, or oxide

Synthesis of YVO4:Eu3+/YBO3Heteronanostructures with Enhanced Photoluminescence Properties

Novel YVO4:Eu3+/YBO3core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures. Photoluminescence (PL) study reveals that PL efficiency of the YVO4:Eu3+nanocrystals (cores) can be improved by the growth of YBO3nanocoatings onto the cores to form the YVO4:Eu3+/YBO3core/shell heteronanostructures. Furthermore, shell ratio plays a critical role in their PL efficiency. The heteronanostructures (SR = 1/7) exhibit the highest PL efficiency; its PL intensity of the5D0–7F2emission at 620 nm is 27% higher than that of the YVO4:Eu3+nanocrystals under the same conditions

On the influence of calcium substitution to the optical properties of Cr3+ doped SrSc2O4

© 2017 Elsevier B.V.Cr3+ doped (Sr,Ca)Sc2O4 samples were synthesized and investigated in view of their potential application as luminescent converters for high power broad band near infrared (NIR) sources. The synthesis of the Cr3+ activated MSc2O4 (M=Ca, Sr) samples was performed by solid state reactions. Obtained powders show broad band near infrared emission between 700 and 1000 nm under excitation in the blue spectral range. The emission is assigned to the intraconfigurational (3d3) 4T2→4A2 transition on Cr3+. As the calcium concentration in SrSc2O4 was increased, a blue shift of the emission spectra was observed. In order to gain insight in the luminescence properties, the crystal field strength, Racah parameters and phonon coupling parameters were examined. Additionally, the influence of temperature in the range between 4 and 500 K on the photoluminescence of the CaSc2O4:Cr3+ and SrSc2O4:Cr3+ was investigated. At 4 K a μs decay time typical of Cr3+ broad band d-d emission was observed. Between 70 and 350 K the decay time and emission intensity decrease due to thermal quenching. The large Stokes shift of the Cr3+ emission (~3000 cm-1) combined with the low energy position of the 4T2 excited state causes non-radiative relaxation to the ground state, already below room temperature. The low thermal quenching temperature of broad band NIR emission is a general problem and the present results provide insight in factors determining thermal quenching

Mercury Free UV Lamp for Disinfection and Purification of Drinking, Process, and Waste Water – An Approach to assessing its Innovation Potential and Possible Market Entry Strategies

Ultraviolet radiation sources found many application areas in science and technology. They play an important role within several markets worldwide today. One of these markets is disinfection and photochemical purification of water which has been a growing market for many decades. At the moment low pressure mercury discharge lamps are the state of the art technology. Although they have been developed towards an impressive maturity level, they still show many drawbacks as e.g. strong temperature dependence. Therefore, this paper is dedicated to a mercury free alternative radiation source for this market, namely so called phosphor converted excimer discharge lamps. They are in the centre of present R&D activities, since they offer several advantages compared to the mercury discharge lamps such as very little temperature sensitivity, a high customisability of the emission spectrum, a large form factor, and instant full radiation power after they have been switched on. A brief description of the technology of phosphor converted excimer lamps will be sketched and furthermore their potential as a possible game changer for water disinfection and photochemical water purification market areas will be highlighted

Luminescence and energy transfer in Lu3Al5O12 scintillators co-doped with Ce3+ and Pr3+

Lu3Al5O12:Ce3+ (LuAG:Ce) is a scintillator with a fast response time. The light yield is lower than theoretically expected and to increase the light yield co-doping with Pr3+ is investigated. To better understand the energy flow to the Ce3+ ion, first low temperature emission and excitation spectra of Pr3+ doped LuAG were investigated, allowing the accurate determination of the zero-phonon lines for the 5d states of Pr3+ in LuAG and the temperature dependent energy transfer from the Self Trapped Exciton to Pr3+. In addition VUV excitation and soft X-ray excited emission spectra of the co-doped LuAG:Ce,Pr were studied. The results show that energy transfer from Pr3+ to Ce3+ occurs but it is followed by back transfer to the 4f states of Pr3+