Moscow University Physics Bulletin最新文献

Helmholtz Free Energy in the Two-Dimensional Ising Model with Defects 含缺陷二维Ising模型中的亥姆霍兹自由能

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700451

V. V. Binkovskii, S. D. Mostovoy

{"title":"Helmholtz Free Energy in the Two-Dimensional Ising Model with Defects","authors":"V. V. Binkovskii, S. D. Mostovoy","doi":"10.3103/S0027134926700451","DOIUrl":"10.3103/S0027134926700451","url":null,"abstract":"The influence of point defects of the vacancy type on the thermodynamic properties of the two-dimensional Ising model is investigated in the paper. The main attention is paid to the comparison of two approaches to the description of the system: the traditional analysis of the internal energy (E) and a more complete analysis of the Helmholtz free energy (F) and entropy (S). Using Monte Carlo methods—the Metropolis algorithm and the Wang–Landau algorithm—the temperature dependences of the changes in the indicated quantities upon the introduction of defects are calculated. It is established that the interaction of defects has the character of attraction with an effective radius of (dapprox 3). It is shown that in the phase transition region, the free energy behaves as a continuous monotonically decreasing function of temperature, whereas the internal energy exhibits a singularity caused by the behaviour of the entropy. The possible dynamics of defects is investigated by comparing the energy of different configurations; a tendency towards defect clustering at temperatures above the critical one is observed. A comparative analysis of the accuracy and computational efficiency of both approaches is carried out.","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":"81 3","pages":"420 - 429"},"PeriodicalIF":0.4,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859880","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}

引用次数: 0

Real-Time Accumulation of Calibration Information and Its Application to Optimal Control for Inaccurate Predictive Models 校正信息的实时积累及其在不准确预测模型最优控制中的应用

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700542

E. M. Churakov, P. V. Golubtsov

{"title":"Real-Time Accumulation of Calibration Information and Its Application to Optimal Control for Inaccurate Predictive Models","authors":"E. M. Churakov, P. V. Golubtsov","doi":"10.3103/S0027134926700542","DOIUrl":"10.3103/S0027134926700542","url":null,"abstract":"The problem of optimal control of a dynamic system in the presence of inaccurate information about its parameters is considered. A continuous real-time parameter calibration approach is proposed, involving the accumulation of calibration information of a special kind for model predictive control. This approach does not require storage of the complete data history and allows the calibration information to be updated and the parameters to be recomputed at each control step. The algorithm developed in the paper is illustrated using the example of the problem of the motion of an object in a viscous medium. The numerical simulation results demonstrated a significant improvement in the control quality after parameter calibration: elimination of oscillations, reduction in overshoot and a decrease in the objective function values. An important feature of the proposed approach is the possibility of refining the model parameters without interrupting the normal operation of the system. A modification of the algorithm that ensures gradual forgetting of calibration information, making it applicable in the presence of parameter drift, is also considered.","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":"81 3","pages":"436 - 447"},"PeriodicalIF":0.4,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859881","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}

引用次数: 0

Features of the Formation of Spins of Fission Fragments in Complete Fusion Reactions of Deformed Nuclei 变形核完全聚变反应中裂变碎片自旋形成的特征

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700414

V. A. Drozdov, D. O. Eremenko, O. A. Yuminov

{"title":"Features of the Formation of Spins of Fission Fragments in Complete Fusion Reactions of Deformed Nuclei","authors":"V. A. Drozdov, D. O. Eremenko, O. A. Yuminov","doi":"10.3103/S0027134926700414","DOIUrl":"10.3103/S0027134926700414","url":null,"abstract":"Within the framework of a dynamical model, an analysis of the energy dependences of the mean spins of fission fragments formed in complete fusion reactions of deformed nuclei has been carried out. The parameters of the dynamical model are determined from the conditions of the best description of experimental data on the mean spins of fission fragments for the reactions ({}^{12})C(+)\u0000 ({}^{232})Th, ({}^{16})O(+)\u0000 ({}^{209})Bi, ({}^{12})C(+)\u0000 ({}^{209})Bi, and ({}^{16})O(+)\u0000 ({}^{232})Th. The influence of the reaction entrance channel on the formation of fission fragment spins of the compound nucleus is discussed. The effect of the entrance channel is considered using the example of the ({}^{12})C(+)\u0000 ({}^{236})U and ({}^{13})C (+)\u0000 ({}^{235})U reactions, leading to the formation of the same compound nucleus ({}^{248})Cf. It is shown that, at sub-barrier collision energies, noticeable differences in the behaviour of the mean spins of fission fragments for different entrance channels of the fusion reaction should be observed.","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":"81 3","pages":"454 - 460"},"PeriodicalIF":0.4,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859882","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}

引用次数: 0

Temporal Analysis of the SOL2015-08-21 Flare Radiation, Theoretical Calculation of Observed Fluxes in the Lines of Calcium, Hydrogen, and Helium. Inhomogeneity of the Flare Structure and the Role of Plasmoids SOL2015-08-21耀斑辐射的时间分析，钙、氢、氦线观测通量的理论计算。耀斑结构的不均匀性和等离子体的作用

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700438

Yu. A. Kupryakov, K. V. Bychkov, V. A. Maliutin, A. B. Gorshkov, O. M. Belova, M. Bárta

{"title":"Temporal Analysis of the SOL2015-08-21 Flare Radiation, Theoretical Calculation of Observed Fluxes in the Lines of Calcium, Hydrogen, and Helium. Inhomogeneity of the Flare Structure and the Role of Plasmoids","authors":"Yu. A. Kupryakov, K. V. Bychkov, V. A. Maliutin, A. B. Gorshkov, O. M. Belova, M. Bárta","doi":"10.3103/S0027134926700438","DOIUrl":"10.3103/S0027134926700438","url":null,"abstract":"We observed an M1.4-class flare in active region NOAA 12403 using the horizontal spectrograph for solar observations (HSFA-2) at the Ondřejov Observatory in the spectral lines of calcium, helium, and hydrogen, as well as using two radio telescopes. The active region remained unchanged over several days, being located in a region of strong magnetic field. It was a typical bipolar region consisting of a group of spots, pores, and bright flocculi. After processing the spectra, the integral radiation fluxes in the H(alpha), H(beta), H(varepsilon), H CaII, IR CaII ((lambda=8542) Å), D3 HeI lines were determined. Then, using the model of heated homogeneous gas layers, a theoretical calculation of the plasma parameters was performed, taking into account the physical conditions in the chromosphere, including self-absorption in the spectral lines. To explain the observed fluxes, three gas layers oriented perpendicular to the line of sight, each with its own individual parameters, had to be considered. One of them is very extended, while the other two are thin, indicating that the flare plasma is highly inhomogeneous. The radio observations carried out at frequencies of 0.8–2.0 GHz revealed drifting pulsating structure with frequency decreasing, which evidences the upward rise of the radio-emission source.","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":"81 3","pages":"503 - 507"},"PeriodicalIF":0.4,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859856","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}

引用次数: 0

Geodynamics of the Eastern Segment of the Greater Caucasus Based on GNSS Observations 基于GNSS观测的大高加索东段地球动力学

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700578

A. P. Mironov, V. K. Milyukov, A. N. Ovsyuchenko, A. S. Larkov, Kh. M. Khubaev

{"title":"Geodynamics of the Eastern Segment of the Greater Caucasus Based on GNSS Observations","authors":"A. P. Mironov, V. K. Milyukov, A. N. Ovsyuchenko, A. S. Larkov, Kh. M. Khubaev","doi":"10.3103/S0027134926700578","DOIUrl":"10.3103/S0027134926700578","url":null,"abstract":"The paper presents the results of a comprehensive study of the geodynamic features of the Eastern Segment of the Greater Caucasus, based on original long-term quasi-continuous satellite-geodetic observations at 28 regional Global Navigation Satellite System (GNSS) stations. The GNSS measurements were processed using the GAMIT/GLOBK software package, designed for high-precision geodetic determinations from radio-navigation satellite signals. As a result of the processing, time series of coordinate increments and displacement velocities of the GNSS stations were obtained in two reference frames, the global ITRF2020 and a regional frame, relative to stable Eurasia. To study the relative displacements of regional tectonic structures, the method of velocity profiling was applied. A 500 km-long profile was selected, extending from south to north with an azimuth of 6.58({}^{circ}). The profiling results revealed relative motions of the main regional tectonic structures. Interpretation of the obtained results in the context of regional seismotectonics provides a detailed picture of the present-day geodynamic situation of the Eastern Segment of the Greater Caucasus.","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":"81 3","pages":"508 - 524"},"PeriodicalIF":0.4,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859898","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}

引用次数: 0

Seiches in Kuril Lake Stimulated by the 2025 Mw 8.8 Kamchatka Earthquake 2025年堪察加8.8级地震引发的千岛湖地震

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700554

M. A. Nosov, D. N. Valeeva

引用次数: 0

On Planar Perturbations in Vertically Stratified Keplerian Discs in a Uniform Magnetic Field 均匀磁场中垂直分层开普勒盘的平面摄动

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700463

K. Yu. Parusov

引用次数: 0

Electronic Properties of the CsPb({}_{1-x})Mn({}_{x})Cl({}_{3}) Solid Solution with the Perovskite Structure 钙钛矿结构CsPb ({}_{1-x}) Mn ({}_{x}) Cl ({}_{3})固溶体的电子性质

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700530

E. D. Rubtsova, A. N. Vasil’ev, I. A. Kamenskikh, I. N. Shpinkov

引用次数: 0

Study of the Middepth Temperature Maximum in Meromictic Lakes of Kandalaksha Bay Based on Mathematical Modeling 基于数学模型的坎大拉沙湾浅成湖泊中深最高温度研究

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700475

I. N. Ivanova, A. V. Klenin, V. M. Stepanenko, E. D. Krasnova, D. A. Voronov

引用次数: 0

Heat Capacity at Constant Pressure on the Saturation Curve of Argon 氩气饱和曲线上的恒压热容

IF 0.4 4区物理与天体物理

Moscow University Physics Bulletin Pub Date : 2026-08-31 DOI: 10.3103/S0027134926700505

P. N. Nikolaev

引用次数: 0