Pub Date : 2024-07-22DOI: 10.1134/s1990793124700015
O. S. Lebedeva, N. G. Lebedev, A. S. Chibrikov, E. N. Shamina
Abstract
This paper is a theoretical study of the piezoresistivity of germanene nanoribbons (GeNRs) of various structural modifications (arm-chair and zig-zag) with acceptor structural defects. Gallium atoms were chosen as impurities. A phenomenological expression for the band structure of nanoribbons (NRs) deformed by tension and compression is proposed. The dependencies of the longitudinal component of the elastic conductivity tensor on the relative deformation of tension and compression, the concentration of impurities, and the width of the NR are analyzed.
摘要 本文是对具有受体结构缺陷的各种结构修饰（扶手椅形和之字形）锗纳米带（GeNRs）的压阻系数进行的理论研究。镓原子被选为杂质。提出了纳米带（NRs）在拉伸和压缩变形时的带状结构现象学表达式。分析了弹性传导张量的纵向分量与拉伸和压缩的相对变形、杂质浓度和 NR 宽度的关系。
{"title":"Elastic Conductivity of Germanene Ribbons with Acceptor Defects","authors":"O. S. Lebedeva, N. G. Lebedev, A. S. Chibrikov, E. N. Shamina","doi":"10.1134/s1990793124700015","DOIUrl":"https://doi.org/10.1134/s1990793124700015","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper is a theoretical study of the piezoresistivity of germanene nanoribbons (GeNRs) of various structural modifications (arm-chair and zig-zag) with acceptor structural defects. Gallium atoms were chosen as impurities. A phenomenological expression for the band structure of nanoribbons (NRs) deformed by tension and compression is proposed. The dependencies of the longitudinal component of the elastic conductivity tensor on the relative deformation of tension and compression, the concentration of impurities, and the width of the NR are analyzed.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700301
M. G. Golubkov, A. V. Suvorova, A. V. Dmitriev, G. V. Golubkov
Abstract
The intense precipitation of energetic electrons from the Earth’s radiation belt (ERB) is one of the most important sources of ionization in the ionosphere and atmosphere. A large-scale statistical analysis is carried out of the data from continuous low-orbit satellite observations of solar-cycle variations in the flux enhancements of the ERB electrons with energy >30 keV at an altitude of 850 km, acquired from the NOAA/POES and MetOp satellites in the interval from 1998 to 2022. The basic features of artificial failures in the satellite database with high-time resolution measurements in the interval from 2014 to 2022 are found and described. Appropriate data correction is carried out. It is shown that the average annual number of days with electron flux enhancements increases rapidly within three years after the solar-cycle maximum and reaches its greatest value near the middle of the declining phase of solar activity. Then the frequency of event occurrence begins to decrease noticeably within an 8-year interval, including the minimum, rising, and maximum phases of the solar cycle. The minimum level is achieved at the maximum solar activity.
{"title":"Statistical Analysis of Flux Enhancements of Energetic Electrons in the Low-Latitudinal Ionosphere According to the Data from the NOAA/POES and MetOp Satellites from 1998 to 2022","authors":"M. G. Golubkov, A. V. Suvorova, A. V. Dmitriev, G. V. Golubkov","doi":"10.1134/s1990793124700301","DOIUrl":"https://doi.org/10.1134/s1990793124700301","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The intense precipitation of energetic electrons from the Earth’s radiation belt (ERB) is one of the most important sources of ionization in the ionosphere and atmosphere. A large-scale statistical analysis is carried out of the data from continuous low-orbit satellite observations of solar-cycle variations in the flux enhancements of the ERB electrons with energy >30 keV at an altitude of 850 km, acquired from the NOAA/POES and MetOp satellites in the interval from 1998 to 2022. The basic features of artificial failures in the satellite database with high-time resolution measurements in the interval from 2014 to 2022 are found and described. Appropriate data correction is carried out. It is shown that the average annual number of days with electron flux enhancements increases rapidly within three years after the solar-cycle maximum and reaches its greatest value near the middle of the declining phase of solar activity. Then the frequency of event occurrence begins to decrease noticeably within an 8-year interval, including the minimum, rising, and maximum phases of the solar cycle. The minimum level is achieved at the maximum solar activity.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700052
E. V. Stegno, V. Yu. Bychkov, N. A. Abramova, A. V. Grachev, V. M. Lalayan, A. Yu. Shaulov, A. A. Berlin
Abstract
In the interaction of high-molecular ammonium polyphosphate with polyethylene polyamine, thermoplastic polymers with Tg = 46.3–50.7°C, Tsoft = 43–92°C, and Tflow = 85–152°C are obtained. Thermal heat resistance, moisture resistance, and the degree of crystallinity depending on the concentration of polyethylene polyamine are measured. The bending strength of polymers and reinforced composites is measured. A chemical scheme for the formation of a polycomplex is proposed and its structure is considered.
{"title":"Low-Melting Hybrid Thermoplastics of Ammonium Polyphosphate","authors":"E. V. Stegno, V. Yu. Bychkov, N. A. Abramova, A. V. Grachev, V. M. Lalayan, A. Yu. Shaulov, A. A. Berlin","doi":"10.1134/s1990793124700052","DOIUrl":"https://doi.org/10.1134/s1990793124700052","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In the interaction of high-molecular ammonium polyphosphate with polyethylene polyamine, thermoplastic polymers with <i>T</i><sub>g</sub> = 46.3–50.7°C, <i>T</i><sub>soft</sub> = 43–92°C, and <i>T</i><sub>flow</sub> = 85–152°C are obtained. Thermal heat resistance, moisture resistance, and the degree of crystallinity depending on the concentration of polyethylene polyamine are measured. The bending strength of polymers and reinforced composites is measured. A chemical scheme for the formation of a polycomplex is proposed and its structure is considered.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700106
A. V. Kuzin, A. V. Lobanov, V. A. Shelonzev, E. A. Eliseeva, A. S. Samadov
Abstract
The kinetics of dissolution and the electrochemical features of the behavior of magnetite (in cathodic polarization) in solutions of sulfuric and orthophosphoric acids are studied. Two independent experimental methods establish that the rate and current of dissolution in H3PO4 are higher than in H2SO4. This pattern is explained based on the stronger complexing properties of various kinds of phosphate anions in comparison with sulfate anions in solution with iron(III) ions. In the range of studied concentrations of orthophosphoric and sulfuric acids, as well as Fe(II) and Fe(III) ions, the reaction orders for orthophosphoric and sulfuric acids are 1.3 ± 0.1; for iron(II) ions, 0.25 ± 0.1; and for iron(III) ions, –0.25 ± 0.1.
{"title":"Process of Magnetite Dissolution in Orthophosphoric and Sulfuric Acid Solutions According to Kinetic and Electrochemical Methods","authors":"A. V. Kuzin, A. V. Lobanov, V. A. Shelonzev, E. A. Eliseeva, A. S. Samadov","doi":"10.1134/s1990793124700106","DOIUrl":"https://doi.org/10.1134/s1990793124700106","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The kinetics of dissolution and the electrochemical features of the behavior of magnetite (in cathodic polarization) in solutions of sulfuric and orthophosphoric acids are studied. Two independent experimental methods establish that the rate and current of dissolution in H<sub>3</sub>PO<sub>4</sub> are higher than in H<sub>2</sub>SO<sub>4</sub>. This pattern is explained based on the stronger complexing properties of various kinds of phosphate anions in comparison with sulfate anions in solution with iron(III) ions. In the range of studied concentrations of orthophosphoric and sulfuric acids, as well as Fe(II) and Fe(III) ions, the reaction orders for orthophosphoric and sulfuric acids are 1.3 ± 0.1; for iron(II) ions, 0.25 ± 0.1; and for iron(III) ions, –0.25 ± 0.1.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700143
V. M. Kumbhar, K. K. Kumar, T. K. Gade, K. D. Sonawane, S. Natarajan, S. A. Jadhav
Abstract
This work deals with phytochemical synthesis of TiO2 nanoparticles by using leaf extract of Ficus benghalensis tree and evaluation of their antibacterial and photocatalytic activities. The synthesized TiO2 nanoparticles were characterized by using X-ray diffraction, Attenuated total reflectance Infrared, UV visible spectroscopy and transmission electron microscopy as well as scanning electron microscopy techniques. The characterizations revealed formation of stable, spherical nanoparticles of anatase phase of TiO2 with average diameter of 21 nm. The particles showed excellent antibacterial activity against Bacillus cereus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The photocatalytic testing showed complete degradation of model pollutants from cationic and anionic dye family namely methylene blue (cationic dye) and methyl orange (anionic dye) that confirmed the excellent photocatalytic activity of the particles.
摘要 本研究利用榕树叶提取物进行植物化学合成 TiO2 纳米粒子，并对其抗菌和光催化活性进行了评估。利用 X 射线衍射、衰减全反射红外光谱、紫外可见光谱、透射电子显微镜和扫描电子显微镜技术对合成的 TiO2 纳米粒子进行了表征。表征结果表明，形成了稳定的锐钛矿相二氧化钛球形纳米粒子，平均直径为 21 纳米。这些颗粒对蜡样芽孢杆菌（革兰氏阳性）和大肠杆菌（革兰氏阴性）具有出色的抗菌活性。光催化测试表明，该颗粒可完全降解阳离子和阴离子染料家族的模型污染物，即亚甲基蓝（阳离子染料）和甲基橙（阴离子染料），这证实了该颗粒具有出色的光催化活性。
{"title":"Photochemical and Antimicrobial Testing of TiO2 Nanoparticles Obtained by a Green Synthesis Method","authors":"V. M. Kumbhar, K. K. Kumar, T. K. Gade, K. D. Sonawane, S. Natarajan, S. A. Jadhav","doi":"10.1134/s1990793124700143","DOIUrl":"https://doi.org/10.1134/s1990793124700143","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This work deals with phytochemical synthesis of TiO<sub>2</sub> nanoparticles by using leaf extract of <i>Ficus benghalensis</i> tree and evaluation of their antibacterial and photocatalytic activities. The synthesized TiO<sub>2</sub> nanoparticles were characterized by using X-ray diffraction, Attenuated total reflectance Infrared, UV visible spectroscopy and transmission electron microscopy as well as scanning electron microscopy techniques. The characterizations revealed formation of stable, spherical nanoparticles of anatase phase of TiO<sub>2</sub> with average diameter of 21 nm. The particles showed excellent antibacterial activity against <i>Bacillus cereus</i> (Gram-positive) and <i>Escherichia coli</i> (Gram-negative) bacteria. The photocatalytic testing showed complete degradation of model pollutants from cationic and anionic dye family namely methylene blue (cationic dye) and methyl orange (anionic dye) that confirmed the excellent photocatalytic activity of the particles.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700209
I. K. Larin, G. B. Pronchev, E. M. Trofimova
Abstract
The reaction rate constant of a chlorine atom with dimethyl sulfide (DMS) is measured in the temperature range 308–366 K by the method of resonant fluorescence (RF) of chlorine atoms. It is shown that the reaction rate constant decreases during experiments at a higher temperature. At a temperature of 308 K, the rate constant of this reaction is measured at different ratios of the reaction time and the diffusion time of chlorine atoms to the reactor wall. The data of these experiments show that with an increase in the diffusion time of the active centers to the surface of the reactor, compared with the contact time of the reagents, a decrease in the measured reaction rate constant is observed. This allows us to assert that the reaction is heterogeneous and the interaction of the chlorine atom with the DMS occurs on the surface of the reactor.
摘要 通过氯原子的共振荧光（RF）方法，测量了氯原子与二甲基硫醚（DMS）在 308-366 K 温度范围内的反应速率常数。实验表明，温度越高，反应速率常数越小。在 308 K 的温度下，按反应时间和氯原子向反应器壁扩散时间的不同比率测量了该反应的速率常数。这些实验数据表明，与试剂的接触时间相比，随着活性中心向反应器表面扩散的时间增加，测得的反应速率常数也随之降低。由此我们可以断定，反应是异质的，氯原子与二甲基亚砜的相互作用发生在反应器的表面。
{"title":"Heterogeneous Reaction of Dimethyl Sulfide with a Chlorine Atom","authors":"I. K. Larin, G. B. Pronchev, E. M. Trofimova","doi":"10.1134/s1990793124700209","DOIUrl":"https://doi.org/10.1134/s1990793124700209","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The reaction rate constant of a chlorine atom with dimethyl sulfide (DMS) is measured in the temperature range 308–366 K by the method of resonant fluorescence (RF) of chlorine atoms. It is shown that the reaction rate constant decreases during experiments at a higher temperature. At a temperature of 308 K, the rate constant of this reaction is measured at different ratios of the reaction time and the diffusion time of chlorine atoms to the reactor wall. The data of these experiments show that with an increase in the diffusion time of the active centers to the surface of the reactor, compared with the contact time of the reagents, a decrease in the measured reaction rate constant is observed. This allows us to assert that the reaction is heterogeneous and the interaction of the chlorine atom with the DMS occurs on the surface of the reactor.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700167
J. Zhang, W. Wang
Abstract
The lanthanide disulfides have been studied many times, but their various physical chemistry properties still need to be improved. In this paper, we carried out calculations based on density functional theory to investigate the structural, electronic, optical, and elastic properties for ultrathin nanostructured praseodymium disulfide. The band structures and density of states were calculations and analyses in the part of electronic property. We also calculated the real and imaginary parts of dielectric function, absorption coefficient, extinction coefficient and reflectivity to deeply analyze the optical properties. It’s found that praseodymium disulfide shows good characteristics required for potential photovoltaic applications. In addition, the elastic properties were evaluated to check mechanical stability and examine relevant elastic parameters such as Young’s modulus, shear modulus, Poisson’s ratio, etc. Our results indicate that praseodymium disulfide has attractive mechanical, electronic, and optical properties, which making this ultrathin nanostructure suitable for photovoltaic device and engineering applications.
{"title":"The Electronic and Optical Properties of Ultrathin Nanostructured Praseodymium Disulfide","authors":"J. Zhang, W. Wang","doi":"10.1134/s1990793124700167","DOIUrl":"https://doi.org/10.1134/s1990793124700167","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The lanthanide disulfides have been studied many times, but their various physical chemistry properties still need to be improved. In this paper, we carried out calculations based on density functional theory to investigate the structural, electronic, optical, and elastic properties for ultrathin nanostructured praseodymium disulfide. The band structures and density of states were calculations and analyses in the part of electronic property. We also calculated the real and imaginary parts of dielectric function, absorption coefficient, extinction coefficient and reflectivity to deeply analyze the optical properties. It’s found that praseodymium disulfide shows good characteristics required for potential photovoltaic applications. In addition, the elastic properties were evaluated to check mechanical stability and examine relevant elastic parameters such as Young’s modulus, shear modulus, Poisson’s ratio, etc. Our results indicate that praseodymium disulfide has attractive mechanical, electronic, and optical properties, which making this ultrathin nanostructure suitable for photovoltaic device and engineering applications.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700118
G. M. Nazin, A. I. Kazakov, T. S. Larikova, A. V. Nabatova, N. N. Volkova
Abstract
The pressure of 1,1-diamino-2,2-dinitroethylene (FOX-7) vapors in the temperature range 140–160°C is determined by the manometric method. The correlation dependence of log Pvap on 1/T is established, which makes it possible to estimate the value of Pvap with satisfactory accuracy in the temperature range of 100–200°C. The kinetics of the reaction in the gas phase are measured at temperatures of 200–230°C and m/V = 10–3–10–4 g/cm3. It is found that under these conditions, in parallel with the usual monomolecular isomerization reaction into the aci-form, a chain process of the direct oxidation of FOX-7 by NO2 proceeds. The consequence of this reaction is a significant decrease in the activation energy observed and the appearance of a dependence of the rate on the experimental conditions. The scheme of the main stages of the chain reaction is presented and the conditions necessary for the manifestation of this reaction are determined.
{"title":"Kinetics of Decomposition of 1,1-Diamino-2,2-Dinitroethylene (Fox-7): 5. Vapor Pressure and Reaction in the Gas Phase","authors":"G. M. Nazin, A. I. Kazakov, T. S. Larikova, A. V. Nabatova, N. N. Volkova","doi":"10.1134/s1990793124700118","DOIUrl":"https://doi.org/10.1134/s1990793124700118","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The pressure of 1,1-diamino-2,2-dinitroethylene (FOX-7) vapors in the temperature range 140–160°C is determined by the manometric method. The correlation dependence of log <i>P</i><sub>vap</sub> on 1/<i>T</i> is established, which makes it possible to estimate the value of <i>P</i><sub>vap</sub> with satisfactory accuracy in the temperature range of 100–200°C. The kinetics of the reaction in the gas phase are measured at temperatures of 200–230°C and m/V = 10<sup>–3</sup>–10<sup>–4</sup> g/cm<sup>3</sup>. It is found that under these conditions, in parallel with the usual monomolecular isomerization reaction into the aci-form, a chain process of the direct oxidation of FOX-7 by NO<sub>2</sub> proceeds. The consequence of this reaction is a significant decrease in the activation energy observed and the appearance of a dependence of the rate on the experimental conditions. The scheme of the main stages of the chain reaction is presented and the conditions necessary for the manifestation of this reaction are determined.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s199079312470009x
A. P. Aldushin, P. M. Krishenik, S. A. Rogachev
Abstract
The methods of mathematical modeling are used to explore the initiation of combustion of a large mass of a condensed mixture in the local contact with the end face of the burning layer. It is shown that the minimum width of the igniting layer is proportional to the width of the thermal front of the combustion wave. The coefficient of proportionality is determined by the initial temperature, heat, and activation energy of the reaction. The calculation results can be used to estimate the effective activation energy of the reaction that controls the combustion mechanism of a gasless system.
{"title":"Ignition of a Gasless Mixture Array by a Combustion Wave","authors":"A. P. Aldushin, P. M. Krishenik, S. A. Rogachev","doi":"10.1134/s199079312470009x","DOIUrl":"https://doi.org/10.1134/s199079312470009x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The methods of mathematical modeling are used to explore the initiation of combustion of a large mass of a condensed mixture in the local contact with the end face of the burning layer. It is shown that the minimum width of the igniting layer is proportional to the width of the thermal front of the combustion wave. The coefficient of proportionality is determined by the initial temperature, heat, and activation energy of the reaction. The calculation results can be used to estimate the effective activation energy of the reaction that controls the combustion mechanism of a gasless system.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700027
V. N. Gorshenev
Abstract
Currently, modified oxidized (intercalated) graphites (OGs) and thermally expanded graphites (TEGs) obtained from them are used to solve many applied problems. This is due to the fact that while retaining all the properties of layered graphite compounds, split graphite particles have important new properties, such as ease of molding, low bulk density, and active interaction with the polymer matrix. However, the question of the mechanisms of expansion of OG and the properties of TEG particles split into layers has not been sufficiently studied. The establishment of experimental patterns of expansion processes of graphite oxidized by acids contributes to the understanding of the set of stages of complex processes occurring during the expansion of graphite particles in a gas atmosphere and in polymer matrices. The aim of this study is to synthesize a colloidal-graphite (CG) suspension based on TEG particles and determine the properties of suspensions and expansion processes of OG during thermal and microwave heating. As a result of modifying TEG with a low bulk density in the activating media, CG suspensions are synthesized without a vibration grinding stage. The splitting of graphite materials after chemical modification by thermal and microwave-stimulated heating leads to the formation of graphene-like structures. The development of techniques for modifying electrically conductive porous samples of materials used as electrodes makes it possible to introduce nanographite particles under the influence of an electric field.
摘要目前，改性氧化（插层）石墨（OGs）和由其制成的热膨胀石墨（TEGs）被用于解决许多应用问题。这是因为在保留层状石墨化合物所有特性的同时，裂解石墨颗粒具有重要的新特性，如易于成型、体积密度低以及与聚合物基体的相互作用活跃等。然而，关于 OG 的膨胀机制和分层 TEG 颗粒的特性问题还没有得到充分研究。建立酸氧化石墨膨胀过程的实验模式有助于了解石墨颗粒在气体环境和聚合物基质中膨胀时发生的一系列复杂过程。本研究的目的是以 TEG 颗粒为基础合成胶体石墨（CG）悬浮液，并确定悬浮液的性质以及热和微波加热过程中 OG 的膨胀过程。由于活化介质中的 TEG 体积密度较低，因此合成 CG 悬浮液无需振动研磨阶段。通过热和微波刺激加热对石墨材料进行化学改性后，石墨材料的分裂导致了类石墨烯结构的形成。对用作电极的材料的导电多孔样品进行改性的技术开发，使得在电场影响下引入纳米石墨颗粒成为可能。
{"title":"Colloidal-Graphite Suspension Based on Thermally Expanded Graphite","authors":"V. N. Gorshenev","doi":"10.1134/s1990793124700027","DOIUrl":"https://doi.org/10.1134/s1990793124700027","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Currently, modified oxidized (intercalated) graphites (OGs) and thermally expanded graphites (TEGs) obtained from them are used to solve many applied problems. This is due to the fact that while retaining all the properties of layered graphite compounds, split graphite particles have important new properties, such as ease of molding, low bulk density, and active interaction with the polymer matrix. However, the question of the mechanisms of expansion of OG and the properties of TEG particles split into layers has not been sufficiently studied. The establishment of experimental patterns of expansion processes of graphite oxidized by acids contributes to the understanding of the set of stages of complex processes occurring during the expansion of graphite particles in a gas atmosphere and in polymer matrices. The aim of this study is to synthesize a colloidal-graphite (CG) suspension based on TEG particles and determine the properties of suspensions and expansion processes of OG during thermal and microwave heating. As a result of modifying TEG with a low bulk density in the activating media, CG suspensions are synthesized without a vibration grinding stage. The splitting of graphite materials after chemical modification by thermal and microwave-stimulated heating leads to the formation of graphene-like structures. The development of techniques for modifying electrically conductive porous samples of materials used as electrodes makes it possible to introduce nanographite particles under the influence of an electric field.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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