Advanced Research in Materials Science

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Authors: Ulambayar Rentsenorov, Batmunkh Davaabal, Jadambaa Temuujin
Abstract: Raw coal fly ash and acid pretreated fly ash were used to synthesize A-type zeolite by hydrothermal treatment. In order to synthesize zeolite A an aqueous gel having a molar batch composition of Na2O:Al2O3:1.926SiO2:128H2O was utilized. Fly ash and zeolitic products were characterized by SEM, XRF, XRD and cation exchange capacity (CEC). After hydrothermal treatment, several types of zeolites were formed: zeolite A, analcime, faujasite and hydroxy-sodalite. The highest content of zeolite A was formed in the mixture treated at 80°C for 8 hours. CEC values of the zeolitic products were 28-38 times higher than that of in raw fly ash. Acid pretreatment which leads to low calcium and iron content is preferable method for processing of fly ash for the zeolite synthesis. Synthesized zeolite can be used for ion exchangers for water treatment.
Authors: Lkhagvajav Sarantuya, Galsan Sevjidsuren, Pagvajav Altantsog, Namsrai Tsogbadrakh
Abstract: Nanosized spinel Li4Ti5O12 was successfully synthesized by a solid state reaction method at 800°C according to the Li4Ti5O12 cubic spinel phase structure. In this synthesizing process, anatase TiO2 and Li2CO3 were used as reactants. The average grain size of the synthesized powders was around 200 nm. The synthesized Li4Ti5O12 powder was characterized X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectrometry (EDS), and Specific Surface Area Analyzer (BET, Brunner-Emmett-Teller) respectively. X-ray diffraction results show that calcination temperature and time have the important effects on the crystal structure of Li4Ti5O12 powder. In this study, we used a first principle method, based on the density functional theory to explore electronic and structural properties of Li4Ti5O12, as anode material for lithium ion batteries. Differences on these properties between delithiation state Li4Ti5O12 and lithiation state Li7Ti5O12 are compared. All the predicted structural and electrochemical properties agree closely with the experimental findings in literature. The average intercalation voltage of 1.4V during charging/discharging were obtained. We have shown that the Li4Ti5O12 material exhibits insulating behavior with the band gap of 3.16 and 3.90 eV using the GGA and GGA+U+J0 calculations respectively. Li7Ti5O12 becomes metallic as Li atoms inserted in Li4Ti5O12 material. Spinel Li4Ti5O12 has been regarded as an attractive anode material for the development of high-power lithium-ion batteries because of its unique attributes of high safety and rate capability.
Authors: Ta Na Bao, Ojin Tegus, Hasichaolu, Jun Ning, Narengerile
Abstract: In this paper, red phosphorus successfully turned to black phosphorus by the mechanical ball milling method. The samples were analyzed by the X-ray diffraction (XRD) method and by high resolution transmission electron microscopy (HRTEM). The XRD result showed that the black phosphorus obtained had small crystal size and a small, amorphous, broadly diffused peak of red phosphorus. The HRTEM analysis showed that the grain size of most of the black phosphorus was small (about 3-5nm). The electron diffraction pattern and the d-spacing on HRTEM correspond well to the characteristic peaks of black phosphorus, such as {111}, {021} and {151}. In some areas, the grain size of black phosphorus was large (about 20-50nm) and contained many defects in crystals. This showed that initially, the amorphous red phosphorus turned into black phosphorus nanocrystals under the action of mechanical milling. Subsequently, the grains were refined and became tiny grains under the action of a large number of edge dislocations in the crystals. During analysis of the TEM, the small size crystals of black phosphorus were rapidly non-crystallized and seriously damaged by electron irradiation. Therefore only the big grains were left after 30 minutes of irradiation.
Authors: Uyat Bayarzul, Jadambaa Temuujin
Abstract: Glass ceramics were prepared from fly ash, waste window glass and fluorite rawmaterials. Mixtures of raw materials were melted at 1300, 1400 and 1500 °C for 4 h and quenchedin cold water. The crystallization behavior of glass ceramics was investigated by differentialthermal analysis-thermogravimetry (DTA-TG). Crystallization at various temperatures (700, 800,900 and 1000 °C) for 30 min was used to obtain the glass ceramics. The obtained glass ceramicswere characterized by X-ray diffraction (XRD), light microscopy and hardness test. XRD studyrevealed that the crystallized phases were plagioclase-type minerals (diopside and albite). TheVickers hardness of the glass ceramics increased from 0.80±0.19 GPa to 6.35±0.35GPa and densityranged from 1.44 g/cm3 to 2.42 g/cm3 depending on the treatment temperature. Glass ceramicsprepared from fused glass melted at 1500 °C temperature showed the highest hardness comparedwith those melted at lower temperatures.
Authors: Tian Xiao, Jing Yan, Ru Xia Duan, Naren Gerile
Abstract: The alloy with the composition of Mg2Ni prepared by low-temperature solid-phase sintering was mechanically milled for 10, 25, 40 and 50 h. The microstructures and electrochemical properties of the Mg2Ni alloys were investigated by X-ray diffraction (XRD), optical microscope (OM) and electrochemical measurements. Furthermore, two broadening effects of XRD peaks caused by crystallite size and lattice strain were separated by the approximate function method and least square method. Crystallite size and lattice strain of the alloy were calculated. The results showed that sintered and milled alloys consist of the Mg2Ni phase. The milled alloys transform partly into nanocrystalline/amorphous structures during the milling process. By calculation, the crystallite size decreases and the lattice strain in the alloy decreases first and then increases with increasing milling time. The discharge capacities of the sintered alloy are significantly improved by milling. The maximum discharge capacities of the milled alloys increase with the increasing milling time.
Authors: Naren Gerile, H. Alata, Tian Xiao, Ta Na Bao, Ojin Tegus
Abstract: Working with acylaminocarboxylate ligands, we used ethanol and water as a solvent, and the europium complexes were prepared using a chemical reaction method in solution. The elements were analyzed and characterized by polarizing microscope and XRD, respectively. The surfaces of complexes in the solid state were observed by polarizing microscope morphology. XRD diffraction data confirms the periodic long range order/disorder structure of these europium complexes. We also found that diversified material was easily formed by the rare earth complexes. Using the above tests, the structural information of the Eu complexes in the glassy state, liquid crystal glassy state and crystalline states was obtained
Authors: G. Munkhbayar, S. Palleschi, F. Perrozzi, M. Nardone, J. Davaasambuu, L. Ottaviano
Abstract: In this study, We demonstrate mono and few layers MoS2 samples on the SiO2(270nm)/Si substrate from bulk MoS2 crystal by micromechanical exfoliation technique. We have systematically studied Atomic Force Microscopy, Raman and PL properties of mono and few layer MoS2 on the SiO2(270nm)/Si substrate. First, we find that the number of layer values dependent the Raman and PL emission. First, Raman intensity area ratio of the MoS2 E12g, A1g and 2LA modes to that area of the Si substrate increased linear with increasing number of layers MoS2. Second, Normalized PL intensity area of the (A) peak decreased linear with increasing number of layers MoS2. The value of those graphs is a method to understand the number of layers the exfoliated MoS2.
Authors: Natalia V. Yumozhapova, Andrey Nomoev, Yuri Ya. Gafner
Abstract: The process of nanoparticle Cu@Si formation by the molecular dynamic method using MEAM-potentials was studied. Modeling the droplet behavior demonstrates that a core-shell structure with a copper core and a silicon shell can be formed if the drop is in the liquid state, until the material is finally redistributed. The parameters of thermal stability of Cu@Si composite nanoparticles of different sizes have been determined. It is concluded that as the temperature increases, the diffusion of copper atoms to the surface begins, which leads to a change in the structure and the formation of particles with a core of the Cu@Si type.
Authors: Deleg Sangaa, Baatartsogt Khongorzul, Enkhnaran Uyanga, Narmandakh Jargalan, Namsrai Tsogbadrakh, Hideyuki Hirazawa
Abstract: In recent time, interest to ferrite magnetic nanomaterials has considerably grown mainly due to their much promising medical and biological applications. The spinel ferrite powder samples having high heat generation ability in AC magnetic field was studied for application to hyperthermia treatment of cancer tumor. These properties of ferrites are strongly depending on their chemical composition, ion distribution, spin orientation and method of preparation in general and crystal structure in particular nature of the material. In this study, several samples of ferrite magnetic structures were investigated by neutron diffraction. The explanation of the mechanism to occurs the heat generation ability in the magnetic materials and the electronic and magnetic states of ferrite-spinel – type structures were theoretically defined by the first-principles calculations within the framework of DFT.

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