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.

Bithreshold Neural Network Classifier

Abstract: The fully connected 2-layer feedforward network architecture with the hidden layer consisting of bithreshold neurons is considered in the paper. We design the neural network multicategory classifier based on such an architecture. We also give the upper bound on the size of the bithreshold network, which is capable to recognize an arbitrary partition of the given finite set of patterns into a predefined number of classes. The learning algorithm is proposed for such neural networks. We give simulation results of the classifier performance on the real data set and discuss the influence of algorithm parameters on the quality of learning and the representational capacity of classifier.

Emission Characteristics of a Glow Discharge in a Mixture of Heavy Inert Gases with Iodine Vapor

Abstract: The results of a systematic investigation of the emission characteristics of a low-pressure UV excimer-halogen lamp pumped by a longitudinal dc glow discharge are presented The discharge was initiated in mixtures of heavy inert gases with iodine vapor at a total pressure of 100–2000 Pa and a power deposited into the plasma of 10–100 W Current-voltage characteristics of the glow discharge and emission spectra of the plasma in the region of 190–360 nm are studied The radiation intensity at the resonance line of the iodine atom (2062 nm) and the intensity at the peaks of the XeI(B-X) (253 nm) and I2(B-X) (342 nm) emission bands are analyzed as functions of the pressure and partial composition of the mixtures of Ar, Kr, and Xe with iodine vapor, as well as the electric power of the glow discharge The most efficient gas mixtures are determined for an electric-discharge UV iodine vapor lamp with continuous-wave emission and a long service life before a change of the mixture is required

Synthesis from aqueous solutions and optical properties of Ag–In–S quantum dots

Abstract: Size-selected series of Ag–In–S and Ag–In–S:Zn quantum dots (QDs) with intense broadband photoluminescence were synthesized in aqueous solutions in the presence of glutathione and mercaptoacetic acid. The bands observed in their Raman spectra are assigned to the corresponding bond vibrations. A noticeable bandgap broadening with addition of a zinc agent at the second stage of the synthesis procedure implies incorporation of Zn into the QD lattice rather than the QD surface passivation by a ZnS shell. The stability of the synthesized QD solutions during long-term storage at room temperature is discussed.

Characteristics of a high-frequency barrier discharge in mixtures of mercury diiodide vapor with gases

Abstract: The spectral and electric characteristics of atmospheric-pressure high-frequency barrier discharge plasma based on mixtures of mercury diiodide with neon and admixtures of argon, xenon, and nitrogen are analyzed. A repetition rate of sinusoidal voltage pulses of about 100 kHz is used both to produce the gas discharge plasma and to excite the components of the working mixture. The radiation of the discharge in the range 200–900 nm is analyzed with a high resolution. It is found that, in the range 400–900 nm, the system of bands of excimer molecules HgI(B → X) emits 85% of the barrier discharge radiation. It is established that the radiation intensity of HgI(B → X) molecules is maximal in the mixture HgI2/Xe/Ne = 0.6/10/90 kPa. In this mixture, UV radiation of molecules XeI(B → X) and XeI(B → A) is observed. The regular features of the spectral and electric characteristics of the gas discharge plasma are discussed. An atmospheric-pressure high-frequency barrier discharge in mixtures of mercury diiodide with gases is of interest for use in a selective (Δλ = 438–446 nm) excilamp with a cylindrical working aperture.