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Каражанов, Смагул Жангабергенович

Организационные подразделения

Организационная единица

Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.

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Каражанов

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Смагул Жангабергенович

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Только метаданные
Thin Ta/Ta oxide core-shell nanoparticle film size-dependent energy structure
(2021) Borisyuk, P. V.; Vasilyev, O. S.; Lebedinskii, Y. Y.; Bortko, D. V.; Karazhanov, S.; Борисюк, Петр Викторович; Васильев, Олег Станиславович; Лебединский, Юрий Юрьевич; Бортко, Диана Владимировна; Каражанов, Смагул Жангабергенович
© 2020 Elsevier B.V.The paper presents the research of thin films, consisting of spherical monodisperse Ta particles. For different samples particle sizes varied from 1.3 nm to 5.8 nm. The films were also exposed to the atmosphere for oxidation, which resulted in formation of a core-shell particle structure, where core was metal and shell was Ta oxide (Ta2O5). Dependency of bandgap Egap and valence band offset (VBO) on particle size has been investigated for the structure by using the X-ray photoelectron spectroscopy (XPS) and reflected electron energy loss spectroscopy (REELS) methods. We have found, that Egap decreases from 4.72 eV to 4.47 eV whereas VBO decreases from 3.50 eV to 2.95 eV with increasing the particle size. A new method of a fine regulation of the electronic structure is suggested, particularly for the application in ultraviolet (UV) photodetector design for low-lying nuclear and electron transitions detection.
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Comparative analysis of photothermal boiling of water enhanced by nano- and micro-particles of carbon black
(2021) Ulset, E. T.; Kosinski, P.; He, Y.; Struchalin, P. G.; Karazhanov, S. Z.; Balakin, B. V.; Стручалин, Павел Геннадьевич; Каражанов, Смагул Жангабергенович
© 2020 Elsevier B.V.The paper describes the effect of sodium dodecyl sulfate (SDS) on the steam generation during photothermal boiling of carbon nanofluids. The considered process finds promising applications for e.g. solar desalination where SDS may boost steam generation. Our study was carried out in a lab system boiling aqueous suspensions of carbon by means of artificial thermal radiation. The experiments demonstrate that the newly-produced nanofluids turn into suspension when no SDS is present in the fluid. The agglomeration of nanoparticles reduces the stability of the system yet degrades the steam generation by no more than 8.2%. The optimum particle concentration was about 2% wt. independently of whether SDS was present in samples. The steam was superheated by up to 12 K when using the surfactant which was 5–7 K higher than without SDS. The experimental data was supported by a theoretical analysis.
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Doping-induced modulation of electronic, optical and wetting properties of CeO2
(2022) Mamedov, D.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
Recently, CeO2 as well as other Rare-Earth Oxides (REOs) have become known as water repelling materials which enables their usage in glass industry. In this study, we investigate electronic, optical and wetting properties of pure and doped CeO2 by first-principles calculations. It is established that introduction of tetravalent doping atoms (Zr, Ti, Sn and Si) significantly modifies the optical response of CeO2 in the visible range by shifting the absorption edge which also effects on the refractive index of the material. For these systems, the water contact angle has been computed through adsorption energy of water layers. We report the intrinsic hydrophilicity of the low-index surfaces of CeO2, which is enhanced by introduction of the impurity atom. Influence of the dopants on the oxygen vacancy formation energy Ef(VO) is considered and discussed with respect to its possible effect on the hydrophobic behavior of CeO2. It is found out that all the considered doping atoms reduce Ef(VO), resulting in enhanced adsorption of the air hydrocarbons at the surface, which leads to an increased water contact angle. Based on the obtained results, an assessment on the applicability of doped CeO2 in glass industry is made. It is concluded that Zr-doped CeO2 possesses the most prominent properties among considered systems for the application as transparent layer. © 2022 The Authors
Только метаданные
Physical and chemical properties of dust in the Pre-Aral region of Uzbekistan
(2022) Bazarbayev, R.; Zhou, B.; Allaniyazov, A.; Zeng, G.; Mamedov, D.; Ivanitskaya, E.; Karazhanov, S.; Каражанов, Смагул Жангабергенович
© 2022, The Author(s).The aim of this work is study of physical and chemical properties of dust of the Pre-Aral region of Uzbekistan such as Karakalpakstan and Khorezm that are located near the three deserts such as the Aralkum, Karakum, and Kyzylkum. The dust particles fell on glass have been collected in Karakalpakstan and Khorezm and studied systematically by employing wide range of methods. Particle volume vs size distribution has been measured with maximum around 600 nm and ~ 10 µm. The major and minor constituent materials present in the dust have been studied systematically by X-ray fluorescence spectroscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectroscopy. Main characteristic absorption bands corresponding to Si–O, Si–O-Si bonding in quartz and Fe–O bonds in hematite Fe2O3 have been identified by infrared and Raman spectroscopy. Quartz, hematite, lime, corundum, magnesia, and several other trace minerals have been identified in the dust particles. X-ray diffraction peaks corresponding to quartz, hematite, and corundum are sharp and are found to be more crystalline with some level of disorder. Analysis of the particle size and crystallinity on human being has been performed: disordered or crystalline quartz can create the lung disease; the particles in the size of 0.5–0.7 µm may produce diseases such as chronic silicosis, silicosis, and silica tuberculosis whereas hematite might create lung disease. Dust particles worsen optical transmittance of glass of the panels. Graphical abstract: [Figure not available: see fulltext.]
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Environmental dependence of the photochromic effect of oxygen-containing rare-earth metal hydrides
(2021) Stolz, L.; Moro, M. V.; Adalsteinsson, S. M.; Chioar, I. A.; Moldarev, D.; Karazhanov, S. Z.; Wolff, M.; Каражанов, Смагул Жангабергенович
© 2021 Author(s).We study the dependence of the photochromic effect on environment and triggering light. We demonstrate that the first darkening/bleaching cycle of freshly grown films is accompanied by a release of weakly bound hydrogen, most likely present at the grain boundaries. For consecutive photochromic cycles, we do not find further exchange of material with the environment. Moreover, we report bleaching kinetics dependent on the gas environment after darkening with light of energies below the optical bandgap of the film. For darkening with photon energies above the bandgap of the film, we report a linear relation between the degree of darkening and bleaching relaxation time irrespective of gas environment.
Только метаданные
Photochromic properties of yttrium oxyhydride thin films: Surface versus bulk effect
(2020) Baba, E. M.; Moro, M. V.; You, C. C.; Primetzhofer, D.; Moldarev, D.; Wolff, M.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
© 2020Photochromic yttrium oxyhydride (YHO) films of different thicknesses but similar chemical composition were grown by reactive magnetron sputtering. Photochromic response of the films defined as the relative change in transmittance upon illumination increases almost linearly with thickness for films below 600 nm and saturates (≈ 50%) for thicker ones. These results suggest that the photochromic effect on YHO films has a bulk nature and might be limited by material transport on the microscale.
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In-situ composition analysis of photochromic yttrium oxy-hydride thin films under light illumination
(2019) Moro, M. V.; You, C. C.; Baba, E. M.; Primetzhofer, D.; Moldarev, D.; Karazhanov, S. Z.; Wolff, M.; Каражанов, Смагул Жангабергенович
© 2019 Elsevier B.V.In this work, we investigate the chemical composition of a reactively sputtered photochromic YHxOy thin film by non-destructive ion beam-based techniques, i.e., Rutherford Backscattering Spectrometry, Particle-Induced X-Ray Emission, Time-of-Flight/Energy coincidence Elastic Recoil Detection Analysis and Elastic Backscattering Spectrometry. To enhance the accuracy of the analysis, the set of spectra was evaluated in an iterative self-consistent approach. This procedure resulted in high-resolution depth profiles of the chemical composition and revealed a thin oxygen-rich-layer on the surface, which apparently does not act as a self-passivation layer. In the film, the concentration of Y remains practically constant, whereas O replaces H during the oxidation process. In-situ light illumination was performed during the compositional analysis in a high vacuum setup. The results from these measurements demonstrate that, for these samples, the induced reversible photochromism is not linked to any detectable change in the bulk composition of the film and can thus take place even in a vacuum environment.
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Methods of estimations of the band gap for kesterite Cu2ZnSnS(Se)(4)
(2019) Mamedov, D.; Yakubov, K.; Bazarbaev, R. B.; Ismailov, K.; Karazhanov, S.; Каражанов, Смагул Жангабергенович
This paper presents a study related to methods of estimation of the band gap for kesterite-type Cu2ZnSnS (Se)(4) based on their electronic structure and optical properties driven by the first-principles calculations within the hybrid functional. The estimations have been performed by four different methods. The first one is based on the band structure estimated as the difference of the energy corresponding to the conduction band and valence band edges. The rest three methods are based on the spectral distribution of the absorption coefficient a(hx) driven from the first-principles calculations: (i) Tauc plot, (ii) first derivative of a(hx) on photon energy hx in the energy range around the fundamental absorption edge, and (iii) linear combination of the methods (i) and (ii). We show that the band gap estimated by different methods can deviate each from other drastically and the large difference is not only relayed to defects, impurities and other lattice imperfections. We show also, that the influence of lattice anisotropy on optical properties of CZTS and CZTSe is negligible. We have pointed out importance of the dependence of dielectric constant on surface texture. The equation describing dependence of dielectric constant on the experimentally observed surface texture is derived. (c) 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the E-MRS Fall Meeting, 2019.
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Preferential Orientation of Photochromic Gadolinium Oxyhydride Films
(2020) Baba, E. M.; Montero, J.; Moro, M. V.; Primetzhofer, D.; Moldarev, D.; Wolff, M.; Karazhanov, S.; Каражанов, Смагул Жангабергенович
We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.
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Influence of Si-nanoparticles on PEDOT:PSS properties for hybrid solar cells
(2019) Mamedov, D.; You, C. C.; Karazhanov, S. Z.; Marstein, E. S.; Каражанов, Смагул Жангабергенович
Hole-conducting poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a material receiving increasing interest for use in photovoltaic devices. In this work, we present the results of study of the degradation of the optical and electrical properties of pure PEDOT:PSS and PEDOT:PSS doped with Si-nanoparticles. The PEDOT:PSS has been deposited on top of Si wafers by spin coating. We found that incorporation of Si nanoparticles into PEDOT:PSS enhances the surface passivation of the surface of the Si wafer by increasing the carrier lifetime measured by the photoluminesence quasi-steady state photoconductance (PL QSS-PC) method from about 320 ms to 420 ms at a minority carrier injection level of 2*10(15) cm(-3). Analysis showed that incorporation of the Si nanoparticles does not change the kinetics of degradation of lifetime considerably. (c) 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the E-MRS Fall Meeting, 2019. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).