Journal of Telecommunications and Information Technology, 2017
The paper summarizes experimental efforts of the Pushkov Institute of Terrestrial Magnetism, Iono... more The paper summarizes experimental efforts of the Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) undertaken in search of the biggest part of Chelyabinsk meteorite in the bottom of lake Chebarkul, South Ural, Russia, and to estimate the ecological effects of its subsequent excavation.
Purpose: Raman Scattering Spectra can be thought of as the "fingerprints" of the investigated mat... more Purpose: Raman Scattering Spectra can be thought of as the "fingerprints" of the investigated material. The purpose of this work was to link the absorbed doses of irradiated radiochromic film at the micrometer level with changes in their Raman spectra.
During magnetron sputtering of graphite using hydrogen as plasma-forming gas, a material sputtere... more During magnetron sputtering of graphite using hydrogen as plasma-forming gas, a material sputtered from the target deposited only on heated substrates. When using currentheated Ni-Fe foils as substrates, carbon deposits of different crystal structures were obtained. The conditions for growing single-crystal graphite layers and single-and multilayer graphenes are found by analyzing deposits by Raman scattering.
<title>Surface and bulk states of disordered carbon and their optical properties</title>
Samples of disordered carbon obtained by different technologies (carbon plasma deposition, irradi... more Samples of disordered carbon obtained by different technologies (carbon plasma deposition, irradiation, anodic etching etc.) by Raman scattering (RS) and photoluminescence (PL) were studied. The common spectral features for these cardinally different technologies preparation samples are found. The following conclusion from the obtained data are made: " In some samples of disordered carbon there are carbon nanoparticles, which consist of
Investigation of semiconductor nanocrystals by Raman scattering
SPIE Proceedings, 2000
The spectra of Raman scattering and photoluminescence of porous Si, Ge, GaP and carbon nanocrysta... more The spectra of Raman scattering and photoluminescence of porous Si, Ge, GaP and carbon nanocrystals are investigated at room temperature. The deduction that porous structures consist of isotropic nanoparticles, which have a crystalline kern is made. Using GaP as an example, it can be shown, that nanocrystals, obtained by an electrochemical etching have more perfect crystalline structure than the initial
<title>Raman spectroscopy in nanopolyacetylene</title>
Optical Devices and Diagnostics in Materials Science, 2000
The evolution of off-resonant and resonant Raman scattering spectra of cis and trans nanopolyacet... more The evolution of off-resonant and resonant Raman scattering spectra of cis and trans nanopolyacetylene (NPA) with change of frequency and intensity of incident laser light was studied. It was found that laser irradiation with wavelength 514.5 nm in process of Raman scattering spectra recording is accompanied by effective cis trans isomerization of approximately 50% cis - 50% trans NPA-PVB blend. The results obtained allow assuming that NPA in the initial compositions is a mixture of two types of nanoparticles.
Development of phase analysis method of high-temperature superconductor YBaCuO by its Raman spectrum
SPIE Proceedings, 2000
Some modification of the YBaCuO phase analysis method using the Raman spectra is proposed. It is ... more Some modification of the YBaCuO phase analysis method using the Raman spectra is proposed. It is based not only on the analysis of the corresponding Raman band maxim positions, as usually, but on the analysis of the integral contours of these bands as well. The 400-500 cm-1 region of Raman spectra of the YBaCuO single crystals was studied for this
Phototransformation and photoinduced oxygen uptake in C60 films irradiated by femtosecond laser pulses
SPIE Proceedings, 1999
Photopolymerization and photoinduced diffusion of the molecular oxygen in oxygen bearing C 60 fil... more Photopolymerization and photoinduced diffusion of the molecular oxygen in oxygen bearing C 60 films by (lambda) equals 459, 514 nm continuous laser radiation and by 100-fs, (lambda) equals 395, 410 nm pulses were compared by visual observation of ...
This paper briefly discusses the advantages of commercial nanodiamond and analyses its structural... more This paper briefly discusses the advantages of commercial nanodiamond and analyses its structural and chemical impurities, polyfunctional surface termination, agglomeration, and other features that may restrict the ND application in academic research and industrial practice. We have designed and tested a novel approach to detonation nanodiamond purification and surface functionalization, using a high temperature treatment in gaseous media containing hydrogen and chlorine. A drastic change in the hydrophily (by a factor of 20) due to thermal treatment at 450°C in a CCl 4 /Ar mixture is demonstrated. The characterization techniques employed (chemical analyses; Raman, FTIR, and ESR spectroscopy; chromatomass spectrometry) can provide a profound nanodiamond modification and its prescribed functionalization.
Effect of electric arc plasma jet treatment on porous silicon properties
SPIE Proceedings, 1996
The effect of arc plasma jet treatment (APJT) on the porous silicon (PS) structure, surface, and ... more The effect of arc plasma jet treatment (APJT) on the porous silicon (PS) structure, surface, and photoluminescence (PL) has been studied. The investigation of PS FTIR absorption spectra indicate that the Ar/air APJT induces the decreasing of the concentration of Si-Hn, C-Hn, (n equals 1, 2, 3) bonds and corresponding increasing of Si-Ox bonds more than an order of magnitude.
ABSTRACTSamples of carbon nanoparticles obtained by different technologies (carbon plasma deposit... more ABSTRACTSamples of carbon nanoparticles obtained by different technologies (carbon plasma deposition, irradiation, anodic etching etc.). by Raman scattering and photoluminescence were studied. It was shown that there are carbon nanoparticles which consist of a core containing sp2 bonds and a shell containing sp3 bonds. These particles have a rather intense photoluminescence. We propose the following photoluminescence mechanism of such nanoparticles: first the nanoparticle core absorbs light; further excitation is transmitted to the external cover or environment where photorecombination occurs. This effect occurs when the size of the particles becomes smaller than the size of the wave function excited state of the nanoparticle. The aim of this research is to check this mechanism.
We used Raman scattering for study the phonon modes of self-organized Ge/Si quantum dots, grown b... more We used Raman scattering for study the phonon modes of self-organized Ge/Si quantum dots, grown by a molecular-beam epitaxy method. It is revealed, that Ge-Ge and Si-Ge vibrational modes considerably intensify at excitation of exciton between the {Lambda}3 valence and {Lanbda}1 conduction bands (transitions E1 and E1+{Delta}1), that allows to observe Raman scattering spectrum from extremely small volumes of Ge,
The ordering of structural units in a cation sublattice and the photorefractive properties of lit... more The ordering of structural units in a cation sublattice and the photorefractive properties of lithium niobate single crystals of different compositions: nominally pure with different [Li|/[Nb| ratios and doped with nonphotorefractive cations Mg ^, Gd ^, and Y ^, are studied by their Raman spectra. It is shown that at low concen trations of Mg^+, Gd^+, and Y^+, the magnitude of the photorefractive effect is determined by the ordering of the structural units of the cation sublattice. It is found for the first time that the intensity of a Raman line corresponding to the bridge valence vibrations of oxygen atoms in the NbOe octahedra is sensitive to the dipole ordering of the cation sublattice.
We present an entirely analytic, leading log order determination of the friction an electroweak b... more We present an entirely analytic, leading log order determination of the friction an electroweak bubble wall feels during a first order electroweak phase transition. The friction is dominated by W bosons, and gives a wall velocity parametrically ∼ α w , and numerically small, ∼ .01 ÷ 0.1 depending on the Higgs mass.
Journal of Experimental and Theoretical Physics Letters, 1998
Photoinduced polymerization and photoinduced diffusion of molecular
oxygen in thin C60 films irr... more Photoinduced polymerization and photoinduced diffusion of molecular
oxygen in thin C60 films irradiated by femtosecond laser pulses are
investigated. A comparison of the Raman scattering and absorbed energy
spectra and the irradiation doses required to observe photopolymerization
using continuous-wave radiation and femtosecond pulses
shows that the efficiency of both photoinduced processes decreases
considerably in the latter case.
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Papers by Nikolay Melnik
oxygen in thin C60 films irradiated by femtosecond laser pulses are
investigated. A comparison of the Raman scattering and absorbed energy
spectra and the irradiation doses required to observe photopolymerization
using continuous-wave radiation and femtosecond pulses
shows that the efficiency of both photoinduced processes decreases
considerably in the latter case.