Doklady Physics最新文献

{"title":"Spatial Reorientation of a Solid Body Using a Moving Mass in the Presence of External Forces Specified as Functions of Time","authors":"A. M. Shmatkov","doi":"10.1134/S1028335824600160","DOIUrl":"10.1134/S1028335824600160","url":null,"abstract":"<p>The spatial motion of a mechanical system consisting of a rigid body and a moving point mass, interacting with each other by means of unspecified internal forces, has been studied. The task is to construct such a trajectory for a point mass moving along which a rigid body under the influence of the force of interaction with this mass that changes its orientation in space according to a known program. It is assumed that there are external forces acting on both objects, which are specified as functions of time. A system of three first-order ordinary differential equations, resolved with respect to derivatives, is obtained, which allows one to solve the problem. These relationships can be used to control spacecraft and robotic systems.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 7-9","pages":"72 - 76"},"PeriodicalIF":0.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculation of the Parameters of a Modified Silicon Carbide Layer during Stoichiometric Hydrogen Ion Sputtering","authors":"V. V. Manukhin","doi":"10.1134/S1028335825600038","DOIUrl":"10.1134/S1028335825600038","url":null,"abstract":"<p>Changes in the surface composition of silicon carbide under hydrogen ion bombardment were studied based on the method of calculating the component composition and thickness of the layer of two-component targets that changed as a result of stoichiometric sputtering under irradiation with light ions. The thickness of the modified layer and its component composition were calculated. The calculations showed that the surface layers are depleted of carbon, which is consistent with the experimental results.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 7-9","pages":"68 - 71"},"PeriodicalIF":0.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis of Nanodiamonds in Kerosene","authors":"B. A. Timerkaev,&nbsp;A. S. Vladimirov,&nbsp;B. R. Shakirov,&nbsp;G. R. Farkhutdinova,&nbsp;R. R. Shaykhattarov,&nbsp;I. G. Galeev","doi":"10.1134/S1028335825600026","DOIUrl":"10.1134/S1028335825600026","url":null,"abstract":"<p>This article considers the possibilities of organizing an arc discharge between graphite electrodes in kerosene with argon supply to the discharge area as applied to the synthesis of carbon nanostructures. The presence of argon was dictated by the conditions of maintaining a low-current discharge in a liquid medium with low viscosity. It is shown that an argon–hydrocarbon arc discharge in kerosene can serve as an effective tool for synthesizing nanodiamonds. The synthesized nanostructures look like a chain of figures that are approximately identical in shape and size. Moreover, these chains are not interrupted anywhere, making up a kind of crystal of nanodiamonds. This may be due to the entry of a particle into a liquid, from the other end of which a new particle begins to form. The synthesized nanodiamonds have sizes from 40 to 100 nm and are built into a linear row one after another. The most interesting thing about these results is that in the immediate vicinity there are no other nanostructures except nanodiamonds, which may be due to the presence of hydrogen, which reacts with unbound carbon atoms and removes them from the discharge area.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 7-9","pages":"77 - 80"},"PeriodicalIF":0.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ab Initio Simulation of Electronic and Magnetic Properties of ZnSe Supercells Doped with 3d Metals","authors":"V. N. Jafarova,&nbsp;V. I. Eminova,&nbsp;U. S. Abdurahmanova","doi":"10.1134/S1028335824600433","DOIUrl":"10.1134/S1028335824600433","url":null,"abstract":"<p>The magnetism of ZnSe supercells doped with 3<i>d</i> transition metals was investigated using the density functional theory. An analysis of the electronic properties of Zn_1–<i>x</i>Me_<i>x</i>Se systems showed additional peaks at the Fermi level due to Me²⁺ 3<i>d</i> levels. The computed magnetic moments for the Me_<i>x</i>Zn_1–<i>x</i>Se supercell systems were found to be 4.0 µ_B for Cr_<i>x</i>Zn_1–<i>x</i>Se, Fe_<i>x</i>Zn_1–<i>x</i>Se, and Ni_<i>x</i>Zn_1–<i>x</i>Se, and the main contribution to the magnetization of these systems is from Me <i>d</i> states. First-principles simulation of total energies for ferromagnetic and antiferromagnetic phases indicated the ferromagnetic phase stability of the Cr_<i>x</i>Zn_1–<i>x</i>Se, Fe_<i>x</i>Zn_1–<i>x</i>Se, and Ni_<i>x</i>Zn_1–<i>x</i>Se systems. Our results demonstrated that the magnetization of Me_<i>x</i>Zn_1–xSe supercell systems strongly depends on the Me concentration. In addition, Curie temperatures were estimated for the investigated materials. The Cr_<i>x</i>Zn_1–<i>x</i>Se and Ni_<i>x</i>Zn_1–<i>x</i>Se systems are half-metallic ferromagnetic materials with higher Curie temperatures. The Cr_<i>x</i>Zn_1–<i>x</i>Se and Ni_<i>x</i>Zn_1–<i>x</i>Se compounds are promising materials for spintronics and Fe_<i>x</i>Zn_1–<i>x</i>Se is a paramagnetic compounds and a useful candidate for optoelectronic devices.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 7-9","pages":"61 - 67"},"PeriodicalIF":0.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of EMIC Waves in Multi-Ion Plasmas: The Role of Beam Velocity and Kappa Distributions","authors":"Rahul Bhaisaniya,&nbsp;Ganpat Ahirwar","doi":"10.1134/S1028335824600573","DOIUrl":"10.1134/S1028335824600573","url":null,"abstract":"<p>The influence of beam velocity and the kappa distribution function on the growth length of electromagnetic ion cyclotron (EMIC) waves in a multi-ion magnetoplasma is analyzed. EMIC waves, characterized by their transverse nature and frequencies below the proton cyclotron frequency, play a vital role in various space plasma phenomena and laboratory plasma environments. The kappa distribution function (<i>k</i>_<i>p</i>), which accounts for non-Maxwellian plasma characteristics with an enhanced high-energy particle tail, is used to model the energy distribution of plasma particles more realistically. We conduct a comprehensive analysis of the nonlinear variation in growth length as a function of wave vector for different beam velocities (<i>V</i>_<i>Dl</i>) and the parameter <span>({{k}_{p}})</span>, focusing on a plasma composed of multiple ion species such as H⁺, He⁺, and O⁺. Our results reveal that increasing negative beam velocities significantly enhance the growth length of EMIC waves, indicating stronger beam-driven instabilities and wave–particle interactions. Additionally, the growth length rises exponentially with increasing wave vector, particularly at higher beam velocities. The parameter <span>({{k}_{p}})</span> exerts a damping effect, where higher values reduce the growth length, suggesting a potential mechanism for controlling wave growth and stabilizing plasma systems. The study also examines how the <span>({{k}_{p}})</span> modifies the dispersion relations, growth rates, and resonance conditions of EMIC waves. The non-Maxwellian energy distribution influences the overall wave behavior, along with the kappa distribution high-energy tail intensifying wave–particle interactions and contributing to the dynamics of wave growth. These findings have significant implications for understanding and controlling plasma instabilities in fusion devices, particle accelerators, and magnetospheric environments. They enhance the modeling of space weather phenomena and provide deeper insight into the interaction between beam velocity and non-Maxwellian plasma distributions, offering valuable contributions to the field of plasma physics and space plasma dynamics.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 7-9","pages":"53 - 60"},"PeriodicalIF":0.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Entropy of Melting of Simple Substances","authors":"V. V. Sagadeev,&nbsp;D. V. Kosenkov","doi":"10.1134/S1028335825600087","DOIUrl":"10.1134/S1028335825600087","url":null,"abstract":"<p>The development of theoretical methods for calculating the entropy of melting of simple substances is reviewed and an attempt is made to explain positional crystal lattice disordering and the melting entropy growth.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 4-6","pages":"23 - 30"},"PeriodicalIF":0.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal Calculation of Expanded Clay Production Furnace","authors":"A. V. Sadykov","doi":"10.1134/S1028335825700016","DOIUrl":"10.1134/S1028335825700016","url":null,"abstract":"<p>Complex heat transfer in an expanded clay production furnace is simulated by two-dimensional differential equations of energy, radiation transfer, motion, continuity, <i>k–</i>ε-turbulence model, and a two-step methane combustion model. The radiation transfer equation is solved using the discrete ordinate method. A comparison of the obtained calculated data with experimental data of other authors is given.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 4-6","pages":"31 - 34"},"PeriodicalIF":0.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regression Analysis Using Neutral Networks for Nondestructive Control of the Thermal Characteristics of Polymers","authors":"A. A. Balashov","doi":"10.1134/S1028335825600063","DOIUrl":"10.1134/S1028335825600063","url":null,"abstract":"<p>An intelligent information-measuring system for controlling the thermal characteristics of materials is a relevant topic related to the issue of finding the middle of a thermogram working section using a neural network as an advanced and accurate way of processing experimental results. The object of study is an information-measuring system for nondestructive testing of structural transitions in polymers. The aim of this study was to derive a new regression equation for the middle of the working section of a thermogram, depending on the thermal activity of a material and the specific thermal power of a flat heater, using a neural network. The obtained experimental dependences of the temperatures in the middle of the working section of a thermograms can be used by technologists who deal with the development of new polymers and the use of existing ones. New results have been obtained using a neural network and reliably described by the derived regression equation. Using the results, the regression equation has been refined to determine the middle of the working section in the method for nondestructive testing of structural transitions in polymers. Using the regression equation, one can predict the temperatures in the middle of a thermogram working section, depending on the power of the heater and the coefficient of thermal activity of the material under study.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 4-6","pages":"35 - 39"},"PeriodicalIF":0.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma Electrolytic Post-Processing of Surfaces for Aircraft Engine Parts Manufactures by Additive Methods","authors":"K. Yu. Nagulin,&nbsp;A. A. Terent’ev,&nbsp;M. D. Belov,&nbsp;A. O. Sukharev,&nbsp;A. Kh. Gil’mutdinov","doi":"10.1134/S1028335825600051","DOIUrl":"10.1134/S1028335825600051","url":null,"abstract":"<p>The paper is devoted to the problems of the immersion (classical) method of electrolytic plasma processing. The immersion method is compared with the jet version. The advantages of the jet version of the plasma electrolytic processing unit are revealed, which, for comparative analysis, was used to polish parts of aircraft engines made of heat-resistant alloys. An alternative version of the plasma electrolytic processing technology showed higher selectivity, versatility, and mitigating of the disadvantages of the classic version.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 4-6","pages":"40 - 47"},"PeriodicalIF":0.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of Heat Transfer in an Internal Combustion Engine Cylinder at the Design Stage","authors":"V. V. Rumyancev,&nbsp;V. A. Lushcheko","doi":"10.1134/S102833582560004X","DOIUrl":"10.1134/S102833582560004X","url":null,"abstract":"<p>The article presents the results of heat transfer modeling in the in-cylinder part of a piston combined diesel engine using the AVL BOOST commercial package at the design stage. The calculation results are compared with the results of bench tests of the R6ChN 13.2/15.8 diesel engine. Heat transfer similarity equations for calculating heat loss in the cylinder-piston section of a diesel engine are recommended.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"69 4-6","pages":"48 - 52"},"PeriodicalIF":0.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}