Uzhhorod National University

About: Uzhhorod National University is a education organization based out in Uzhhorod, Ukraine. It is known for research contribution in the topics: Raman spectroscopy & Laser. The organization has 1089 authors who have published 1056 publications receiving 5187 citations. The organization is also known as: State Higher Education Establishment "Uzhhorod National University" & Uzhhorod State University.

Long-Term Stability of Optical Properties of Colloidal CdSe Nanocrystals in Polymer Matrices

Abstract: Properties of CdSe nanocrystals (NCs) fabricated in aqueous solutions at relatively mild conditions in the presence of gelatine and stabilized in polymer (gelatine, gelatine + polyvinylpyrrolidone,...

Fragmentation of threonine under low-energy electron impact

Abstract: New data have been obtained on the fragmentation of a threonine ( $$\hbox {C}_{{4}}\hbox {H}_{{9}}\hbox {NO}_{{3}}$$ ) molecule (i.e., ionized product formation) under low-energy electron impact. This was accomplished using a mass spectrometric experimental technique in combination with an extensive DFT-theory approach. Based on the results, the main pathways of threonine molecule’s fragment yield are suggested. The absolute values of the appearance energies for some ion fragments have been experimentally measured, theoretically calculated, and analyzed.

Emission from a Transverse Volume Discharge in Neon with Small Admixtures of Water Vapor and Air

Abstract: Emission from the plasma of a pulsed discharge in neon with small admixtures of water vapor and air in the wavelength range 210–620 nm is investigated. A transverse volume discharge with spark UV preionization is ignited in neon at a pressure of 100–200 kPa and charging voltage of Uch≤20 kV. It is shown that the discharge acts as a source of pulsed UV radiation on OH(A-X) (λ=308–314 nm) and NO(B-X) (247.8 nm) transitions, which is of interest for the use in an ecologically safe lamp based on the mixtures of neon with water vapor and air. In the visible spectral region, plasma emission consists of the NeI (3s, 3s′-3p, 3p′) band and Hβ 486.1-nm spectral line. On the short-wavelength side of the spectrum, a broadband emission (the third continuum of neon) is observed, whose intensity increases with increasing neon pressure and decreasing emission wavelength.

UV Radiation Source Based on the Plasma of a Glow Discharge in a Mixture of Helium with Water Vapors

Abstract: The results on the optical characteristics of the glow–discharge plasma in an He/H2O mixture are presented. It has been established that it is a source of UV radiation in the region 306–315 nm (λmax = 309.6 nm). Radiation lines of the atoms of hydrogen (Hβ 486.1 nm and Hα 656.3 nm) and helium (491.1, 501.1, 587.6, and 667.8 nm) were recorded in the visible region of the spectrum; they can be used as diagnostic lines in measuring the parameters of this plasma (ne, Te) by the method of emission spectroscopy. The intensity of the UV bands and of the spectral lines HI and HeI have been optimized depending on the partial pressure of helium and the discharge current. The results obtained are of interest for the development of an ecologically pure source of UV radiation on the basis of chemiluminescence of water vapors in a longitudinal glow discharge.

A Pulsed-Periodic Low-Pressure Volume Discharge in a Krypton-Chlorine Gas Mixture

Abstract: The initiation conditions and characteristics of a volume discharge in a krypton-chlorine mixture at low pressures (P≤1.0 kPa) were studied. It is shown that a constant voltage of Uch 1.0 kV applied to a spherical anode-flat cathode system gives rise to a pulsed-periodic discharge with a pulse repetition rate of 1–50 kHz. The current-voltage characteristics of the discharge, the spectra of emission in a wavelength interval of Δ λ=130–350 nm, and oscillograms of the current and the total output emission intensity were studied as dependent on the partial composition and pressure of the krypton-chlorine mixture. It is shown that the discharge is a selective source of emission in the electronic-vibrational bands with λ=257 nm [Cl2(D′-A′)], 222 nm [KrCl(B-X)], and 200 nm [C12**]. The volume discharge in the Kr-Cl2 mixture can be used for the development of pulsed-periodic low-pressure excimer-halogen lamps.