Electrochemical Study of Graphene Coated Nickel Foam as an Anode for Lithium-Ion Battery

This study reports the synthesis of a few-layered graphene (GF) thin film on Ni foam by chemical vapor deposition (CVD) technique and investigation of its electrochemical performance as a negative electrode for lithium-ion batteries (LIBs). A standard deposition procedure with a methane precursor was employed to prepare the GF films. The SEM studies revealed the formation of a dark uniform film on the surface of Ni foam’s wires upon the CVD deposition. The film consisted of numerous GF sheets replicating the shape of the Ni grain boundaries over the Ni wire surface. The Raman spectroscopy of the prepared films on the Ni foam confirmed that the samples are a few-layered GF with high quality and purity. In order to evaluate the  potential of the use of the prepared materials as an anode in LIBs, their electrochemical performance was studied in coin-type lithium half-cells using cyclic voltammetry (CV) and galvanostatic cycling. The results of CV showed that both graphene and native oxide layer (NiO) on nickel foam exhibit electrochemical activity with respect to lithium ions. Galvanostatic cycling revealed that both GF and NiO contribute to the overall capacity, which increases upon cycling with a stable Coulombic efficiency of around 99%. The designed 3D GF coated NiO/Ni anode demonstrated a gradual increase of its areal charge capacity from 65 μAh cm-2 at the initial cycle to 250 μAh cm-2 at the final 250th cycle

Quantitative analysis of the learning curve obtained for foreign language studies

The article presents the results of an experimental construction and quantitative analysis of the learning curve (LC) obtained from individuals learning a foreign language. The experiment was conducted at the Ural Federal University named after the first President of Russia B.N. Yeltsin. Three types of LC were constructed for different level of English skills of the subjects: Pre-Intermediate, Intermediate and Upper-Intermediate. Comparison of these curves demonstrates that the subject's knowledge acquisition keeps running for 14 hours after the flash memory session. The paper presents two dependencies for constructing an approximation of the learning curve: logarithmic and polynomial. Based on a comparison of the approximation of the experimental LCs with functions of various types, we suggest that they all provide satisfactory results. Based on the results plans for further study of the problem were proposed. © 2020 American Institute of Physics Inc.. All rights reserved

The Contribution of Genetic Variants to the Risk of Papillary Thyroid Carcinoma in the Kazakh Population: Study of Common Single Nucleotide Polymorphisms and Their Clinicopathological Correlations

Objective: Risk for developing papillary thyroid carcinoma (PTC), the most common endocrine malignancy, is thought to be mediated by lifestyle, environmental exposures and genetic factors. Recent progress in the genome-wide association studies of thyroid cancer leads to the identification of several genetic variants conferring risk to this malignancy across different ethnicities. We set out to elucidate the impact of selected single nucleotide polymorphisms (SNPs) on PTC risk and to evaluate clinicopathological correlations of these genetic variants in the Kazakh population for the first time. Methods: Eight SNPs were genotyped in 485 patients with PTC and 1,008 healthy control Kazakh subjects. The association analysis and multivariable modeling of PTC risk by the genetic factors, supplemented with rigorous statistical validation, were performed. Result: Five of the eight SNPs: rs965513 (FOXE1/PTCSC2, P = 1.3E-16), rs1867277 (FOXE1 5’UTR, P = 7.5E-06), rs2439302 (NRG1 intron 1, P = 4.0E-05), rs944289 (PTCSC3/NKX2-1, P = 4.5E-06) and rs10136427 (BATF upstream, P = 9.8E-03) were significantly associated with PTC. rs966423 (DIRC3, P = 0.07) showed a suggestive association. rs7267944 (DHX35) was associated with PTC risk in males (P = 0.02), rs1867277 (FOXE1) conferred the higher risk in subjects older than 55 years (P = 7.0E-05), and rs6983267 (POU5F1B/CCAT2) was associated with pT3–T4 tumors (P = 0.01). The contribution of genetic component (unidirectional independent effects of rs965513, rs944289, rs2439302 and rs10136427 adjusted for age and sex) to PTC risk in the analyzed series was estimated to be 30–40%. Conclusion: Genetic factors analyzed in the present work display significant association signals with PTC either on the whole group analysis or in particular clinicopathological groups and account for about one-third of the risk for PTC in the Kazakh population

CVD graphene growth on a surface of liquid gallium

Abstract This paper presents the results of the experiments on graphene growth on the surface of a liquid metal gallium that appeared to have the catalytic ability in respect to carbon atoms. Due to the absence of crystal lattice, the liquid catalyst does not influence the graphene formation and as a result, the latter has uniform hexagonal structure. The work comprises the data on graphene synthesis on the surface of pure gallium with different precursors and on the surface of pre-treated gallium without any precursor. Obtained materials were characterized by RAMAN, TEM, SEM and FT-IR techniques

EFFECT OF DOPING WITH CATIONS AND ANIONIC GROUPS ON THE IONIC CONDUCTIVITY PROPERTIES OF LATP SOLID ELECTROLYTES FOR LI-ION BATTERIES

The good energy capacity of lithium-ion batteries (LIBs) makes them promising electrochemical energy storage devices. Existing commercial batteries use flammable liquid electrolytes, which are unsafe, toxic and environmentally unsound, and have poor chemical stability. Recently, solid Li-ion conducting ceramic electrolytes have received considerable attention, since they combine high ionic conductivity with low electrical conductivity, chemical stability and potentially sufficient mechanical properties

The effect of ancient totemic beliefs on the Kazakh traditional singing

The Kazakh musical culture has undoubtedly a rich history that stretches back to ancient time. The philosophy of the Kazakh people is laced with mythological beliefs, with belief in higher forces, magic. Music has always had a sacral meaning for the Kazakhs; all the major life stages were accompanied with the corresponding folk songs. Totemic beliefs occupy a special place in the philosophy of the Kazakh music. This article seeks to establish the relationship between totemic in the Kazakh culture and traditional singing. The evolution of totemic symbols and their role in the life of Kazakh people were observed.La cultura musical kazaja tiene, sin duda, una rica historia que se remonta a la antigüedad. La filosofía del pueblo kazajo está ligada a creencias mitológicas, a creencias en fuerzas superiores, magia. La música siempre ha tenido un significado sagrado para los kazajos; todas las principales etapas de la vida fueron acompañadas con las canciones populares correspondientes. Las creencias totémicas ocupan un lugar especial en la filosofía de la música kazaja. Este artículo busca establecer la relación entre totémico en la cultura kazaja y el canto tradicional. Se observó la evolución de los símbolos totémicos y su papel en la vida de los kazajos

Study of oxygen and steam interactions with rgt graphite

Corrosion in air and water remains a problem for graphite as an important structural material of nuclear reactors. Changes in the gas composition in corrosion chamber with samples of RGT graphite have been studied. The sample was linearly heated to 1100C with 10C /min rate, and held at this temperature for 1800 s. Then the sample was cooled down within the same rate. During the experiment changes in the gas composition in the chamber were registered within the mass range 1-70. The time and temperature dependencies of steam, oxygen and gaseous corrosion products of RGT graphite have been obtained. Arrhenius dependencies and activation energy of rate constants of graphite interaction with the following products were derived: oxygen-graphite (mole/(sm2Pa)),water-graphite (mole/(sm2Pa)