Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

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Anomalous Sorption of Yttrium Ions by the Mutual Activated Hydrogels in the Interpolymer System of Poly(Methacrylic Acid) and Poly(4-Vinylpyridine)
(Lviv Polytechnic National University, 2023-03-26)
Talkybek Jumadilov
;
Bakytgul Totkhuskyzy
;
А. М. Imangazy
;
Juozas V. Gražulevičius
This paper considers the effect of mutual activation of poly(methacrylic acid) (PMAA) and poly-(4 vinylpyridine) (P4VP) hydrogels during their remote interaction on the degree of yttrium ions sorption from an aqueous medium. Electrochemical properties were studied by conductometry and pH measurements to predict the activation possibility of these hydrogels. pH measurements showed that at 0.1 hour, the pH values were the lowest, indicating a high content of H+ ions in the aqueous solution. An increase in the interaction time to 24 hours leads to an increase in pH values, indicating a decrease in the content of H+ ions in the solution. The dependences of the specific electrical conductivity were studied. The experiments showed that the maximum values were observed at the ratios of 3 : 3 and 1 : 5 (gPMAA : gP4VP), which coincided with the result of pH measurements. The obtained results indicate the significant changes occurred in the electrochemical and conformational values of the initial macromolecules in the interpolymer system. Our research confirms the presence of remote interaction between hydrogels and their mutual activation.
Цитирования (OpenAlex) 8Цитирования (OpenCitations) 5
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Sintering Atmosphere and Polytype Effects on Porous Silicon Carbide Ceramics
(2025-01-01)
Shynar Kultayeva
;
Bibol Yermuratovich Zhakipbayev
;
Zhangazy Nurzhanovich Moldamuratov
;
Hyun-Sik Kim
;
Nazgul Akimbayeva
This study investigates the effects of sintering atmosphere and polytype on the electrical and thermal conductivities, and flexural strength of porous SiC ceramics.The porosity was maintained at approximately 38.2%.The nitrogen sintered porous SiC ceramic fabricated from β-SiC powder exhibited the electrical conductivity of 1.2 × 10 1 (Ωcm) -1 which was two orders of magnitude higher than that of a porous SiC ceramic fabricated from α-SiC powder (5.0 × 10 -1 (Ωcm) -1 ).The highest thermal conductivity of 19.5 W/mK and flexural strength of 22.0 MPa showed porous SiC ceramics fabricated from α-SiC powder when sintered in argon and nitrogen atmosphere, respectively.The lowest thermal conductivity of 12.0 W/mK and flexural strength of 5.8 MPa porous SiC ceramics fabricated from β-SiC powder when sintered in nitrogen and argon atmospheres, respectively.Electrical conductivity was primarily determined by the incorporation of nitrogen into the SiC crystal lattice, whereas the thermal conductivity and flexural strength mainly dependent on the microstructure of the material.
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Novel Spinel Li–Cr Nano-Ferrites: Structure, Morphology, and Electrical/Dielectric Properties
(Multidisciplinary Digital Publishing Institute, 2025-10-26)
Mukhametkali Musagalievich Mataev
;
Altynai Madiyarova
;
Moldir Rashidovna Abdraimova
;
Marzhan Nurbekova
;
Karima Seibekova
This article reports on the synthesis and physicochemical characterization of a novel complex ferrite material, LiCr3.4Fe1.6O8, prepared via the sol-gel method. X-ray diffraction (XRD) analysis confirmed that the synthesized compound is a single-phase material with a spinel-type structure and cubic symmetry. Raman spectroscopy was employed to investigate the vibrational modes, and the observed peaks corresponding to Fe–O and Cr–O bonds further validated the spinel-like structure of the compound. The microstructure and elemental composition were examined using scanning electron microscopy (SEM). Multiple regions of the LiCr3.4Fe1.6O8 crystals were analyzed, revealing a homogeneous phase and providing detailed insight into the morphology and chemical composition of the surface. The synthesized ferrite particles exhibited relatively large dimensions, with sizes measured at approximately 5, 30, 100, and 200 μm. The dielectric behavior was studied to assess the material’s response to an external electric field, demonstrating its capacity for electric charge polarization. Both capacitance and electrical conductivity were found to increase with rising temperature. Electrophysical measurements were conducted using the LCR-800 system over a temperature range of 293–483 K and at frequencies of 1.5 kHz and 10 kHz. An increase in frequency to 10 kHz resulted in a decrease in the dielectric constant (ε) across the entire temperature range.
Цитирования (OpenAlex) 3Цитирования (OpenCitations) 1
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Electrical Conductivity of Polyaniline/Zinc Oxide Nanocomposites: Effect of Zinc Oxide Nanoparticle Content, Morphology and Laser Irradiation
(2026-01-01)
M. A. Makhkamov
;
Islomjon Khudoyberdiyev
;
Mavluda Khidirova
;
Iroda GʻULOMOVA
;
Nasiba Khodjayeva
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FeMnO3: Synthesis, Morphology, Dielectric Properties, and Electrochemical Behavior Toward HER by LSV
(Multidisciplinary Digital Publishing Institute, 2026-02-27)
Mukhametkali Musagalievich Mataev
;
Zamira Sarsenbaeva
;
Marzhan Nurbekova
;
Ramachandran Krishnamoorthy
;
Bahadır Keskin
This paper presents a comprehensive investigation into the synthesis, morphological characteristics, electrical conductivity, dielectric behavior, and electrocatalytic activity of perovskite-structured iron manganite (FeMnO3), with a specific focus on its performance in the hydrogen evolution reaction (HER). FeMnO3(FMO) nanoparticles (NPs) were synthesized using a sol–gel-type Pechini method and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (FESEM-EDS). XRD analysis confirmed the formation of a crystalline structure with cubic symmetry assigned to the Ia-3 space group, with an average crystallite size of 52.47 nm. FESEM images revealed a relatively uniform morphology with an average particle diameter of 55.84 nm. The redox and oxidation states of Fe and Mn can be studied by temperature-programmed oxidation (TPO-O2) in order to understand oxygen uptake and metal oxidation processes occurring within the FMO lattice. The dielectric constant, dielectric loss, electric modulus and electrical conductivity were calculated as a function of frequency and temperature using a Novocontrol Alpha-A broadband dielectric spectrometer (Novocontrol system) coupled with the LCR-800 precision meter. The dielectric data reveal that the FMO has semiconducting behavior with dominant charge- or ionic-relaxation processes. The electrocatalytic activity toward the HER was evaluated using linear sweep voltammetry (LSV), with the working electrode modified by an FMO catalyst ink. The material exhibited significant catalytic activity within the HER potential range, and an increase in the number of cycles led to stabilized current and enhanced hydrogen evolution. These results highlight the stability of FeMnO3 for hydrogen generation.
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Structural and Functional Properties of the Oxide System LaCaCuVMnO7.5 and Its Composites with YBa2Cu3Ox
(Multidisciplinary Digital Publishing Institute, 2026-07-06)
Zhenisgul Imangalievna Sagintaeva
;
Shuga Bulatovna Kasenova
;
Bulat Kunurovich Kasenov
;
Erbolat Ermekovich Kuanyshbekov
;
Aigul Tanirbergenovna Ordabaeva
Oxide systems with the nominal composition LaCaCuVMnO7.5 and composites modified with the YBa2Cu3Ox phase were synthesized by the solid-state reaction method. The phase composition and structural features were systematically investigated by X-ray diffraction (XRD), Rietveld refinement, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). The parent oxide was found to form a two-phase system, consisting of an orthorhombic perovskite-like phase and a cubic manganite–vanadate phase, whereas the introduction of 10 wt.% YBa2Cu3Ox resulted in the formation of a three-phase composite containing an additional cuprate phase. Thermophysical investigations in the 298–673 K range revealed λ-type-like anomalies in the heat capacity, which may be associated with possible structural or interphase transformations in the investigated oxide systems. The incorporation of YBa2Cu3Ox significantly modified the temperature dependence of heat capacity and increased its values over both low- and high-temperature regions. Electrophysical measurements in the 293–483 K range confirmed the semiconducting nature of conductivity, while the addition of YBa2Cu3Ox reduced electrical resistance and enhanced dielectric permittivity. These findings demonstrate that YBa2Cu3Ox modification provides an effective route for tuning the thermophysical and electrophysical properties of LaCaCuVMnO7.5-based oxide systems, suggesting their potential as promising candidates for multifunctional oxide materials with possible electronic and sensor-related applications.

Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

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