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Dispersive shock wave theory for nonintegrable equations
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. 2019. Vol. 99. No. 1. Article 012203.
Kamchatnov A.M.
We suggest a method for calculation of parameters of dispersive shock waves in the framework of Whitham modulation theory applied to nonintegrable wave equations with a wide class of initial conditions corresponding to propagation of a pulse into a medium at rest. The method is based on universal applicability of Whitham’s “number of waves conservation law” as well as on the conjecture of applicability of its soliton counterpart to the above mentioned class of initial conditions which is substantiated by comparison with similar situations in the case of completely integrable wave equations. This allows one to calculate the limiting characteristic velocities of the Whitham modulation equations at the boundary with the smooth part of the pulse whose evolution obeys the dispersionless approximation equations. We show that explicit analytic expressions can be obtained for laws of motion of the edges. The validity of the method is confirmed by its application to similar situations described by the integrable Korteweg–de Vries (KdV) and nonlinear Schrödinger (NLS) equations and by comparison with the results of numerical simulations for the generalized KdV and NLS equations.
Бондаренко Г.Г., Кристя В. И., Савичкин Д. О. et al., Поверхность. Рентгеновские, синхротронные и нейтронные исследования 2026 № 4 С. 29–36
Сформулирована модель тлеющего газового разряда в смеси аргона и паров ртути при наличии
на поверхности катода тонкой диэлектрической пленки. Рассчитаны зависимости характеристик
разряда от температуры в интервале ее изменения, в котором заметный вклад в ионизацию
рабочей газовой смеси дает ионизация атомов ртути метастабильными возбужденными атомами
аргона (реакция Пеннинга). Показано, что в случае катода без диэлектрической пленки при
повышении температуры до ...
Added: June 20, 2026
Chertenkov V. I., Shchur L., Lobachevskii Journal of Mathematics 2026 Vol. 47 No. 2 P. 720–727
Supervised machine learning is successfully applied to the study of critical phenomena and allows us to obtain a numerical estimate of the phase transition temperature and the correlation length exponent. We discuss the influence of possible systematic errors, as well as statistical errors, on the accuracy of such numerical estimates. Errors in the training and ...
Added: June 16, 2026
Батурин А. С., Гаврилов В. Р., Иванов А. В. et al., Измерительная техника 2026 Т. 75 № 2 С. 14–28
28 декабря 2025 года Всероссийскому научно-исследовательскому институту оптико-физических измерений (ВНИИОФИ) исполнилось 60 лет. За прошедшие десятилетия институт выполнил значительное количество научных исследований, разработал и поставил потребителям тысячи высокоточных средств оптико-физических измерений (включая эталонное оборудование). В статье представлены наиболее значимые для метрологического обеспечения оптико-физических измерений результаты научно-исследовательских работ, выполненных ВНИИОФИ за период 2016–2025 гг. ...
Added: June 15, 2026
Вишняков Г. Н., Левина Э. Ю., Minaev V., Измерительная техника 2025 Т. 74 № 2 С. 20–27
Качество формируемого оптической системой изображения определяется её частотно-контрастной характеристикой или коэффициентами передачи модуляции на различных пространственных частотах. Для обеспечения единства измерений коэффициентов передачи модуляции и создания эталонной базы по воспроизведению, хранению и передаче единицы коэффициента передачи модуляции усовершенствован Государственный первичный эталон единиц оптической силы очковой оптики ГЭТ 205-2013 в части воспроизведения единицы коэффициентов передачи модуляции ...
Added: June 15, 2026
Filippova A. V., Yurchenko N. Y., Smirnov S. A. et al., Journal of Alloys and Compounds 2026 No. 1074 Article 189162
This study investigates the effects of post-processing heat treatment at 300–500 °C on the microstructure, hardness, and tensile properties of laser powder bed fusion (PBF-LB) processed Al-bronze processed with energy densities (ED) in the range of 125–938 J/mm3. In the as-printed state, sharp needle-like α + β′ laths form at lower ED whereas with increasing ED, the β′ ...
Added: June 12, 2026
Konakov V., Kucher D., Mammen E., / Series arXiv "math". 2026. No. 2606.11142v1.
In this paper, we construct strong approximations for discrete-time Markov chains weakly converging to continuous diffusion processes, as well as for their perturbed counterparts. Under the assumption of bounded coefficients, we construct closely coupled versions of these processes on a shared probability space. In particular, for both non-degenerate and degenerate cases, we maximize the probability ...
Added: June 11, 2026
Спонтанное образование скин-слоя в воде с деформацией ОН-полосы КР вкладом компоненты льда 3200 см-1
Першин С. М., Степанов Е. В., Артемова Д. Г. et al., Письма в Журнал экспериментальной и теоретической физики 2026 Т. 123 № 6 С. 383–390
Открыто спонтанное образование в течение 4 ч скин-слоя дистиллированной воды толщиной до 3 мм при комнатной температуре с новыми свойствами. Обнаружены деформация ОН-полосы комбинационного рассеяния вкладом компоненты льда ( 3200 см-1), снижение коэффициента упругого рассеяния и его флуктуаций, а также увеличение на 20 капиллярах. Восстановление слоя после обогащения воздухом в результате перемешивания указывает на стабильность ...
Added: June 8, 2026
Springer, 2026.
The book presents the proceedings of the 13th International Conference on Frontiers of Intelligent Computing: Theory and Applications (FICTA 2024), held at Intelligent Systems Research Group (ISRG), London Metropolitan University, London, United Kingdom, during June 6–7, 2025. Researchers, scientists, engineers and practitioners exchange new ideas and experiences in the domain of intelligent computing theories with ...
Added: June 8, 2026
N.S. Artekha, D.R. Shklyar, Physics of Plasmas 2026 Vol. 33 No. 6 Article 062105
The peculiarities of resonant interaction between slow extraordinary (SE) waves and relativistic electrons have been studied. General equations of motion of relativistic electrons in the field of SE wave and a uniform ambient magnetic field are derived. Conditions of applicability of the isolated resonance approximation are elucidated. In this approximation, the equations of motion are reduced to one-dimensional set of ...
Added: June 6, 2026
Zirnik G., Ostovari Moghaddam A., Zhukov S. et al., Journal of Materials Science: Materials in Electronics 2026 Vol. 37 Article 738
In regards to the advances in InGaZnO for flexible transistors applications, herein for the first time we measure the broadband radio-frequency range (10 Hz to 1 MHz) dielectric permittivity ε′ and electrical conductivity σ of InGaZnO4 nanoparticle layers at different temperatures ranging from 10 to 300 K. The InGaZnO4 nanoparticles prepared by metal–nitrate–glycol gel decomposition method exhibited ...
Added: June 6, 2026
Flamarion M. V., Pelinovsky E., Nonlinear Dynamics 2026 Vol. 114 Article 784
In this article, we investigate wave packet and solitary wave dynamics in the Whitham–Ostrovsky (WO) equation. By means of a multiple-scales expansion, we formally derive a nonlinear Schrödinger (NLS) equation governing the envelope evolution.The corresponding modulational stability diagram is then obtained using the Lighthill criterion. We show that sufficiently large values of the low-frequency dispersive term render ...
Added: June 5, 2026
Hazarika A. P., Das A., Das S. K. et al., Physica B: Condensed Matter 2026 Vol. 738 Article 418803
Lemon grass (Cymbopogon citratus, LG-SiO2), horsetail (Equisetum debile, SG-SiO2), and cassava leaves (Manihot esculenta, CL-SiO2) were used to green-synthesize silica (SiO2) nanoparticles (NPs). While LG-SiO2 and SG-SiO2 had strong (101) peaks and a large 22° amorphous peak, XRD of CL-SiO2 verified crystallinity. LG-SiO2 (agglomerated porous), SG-SiO2 (rectangular-cube agglomerates), and CL-SiO2 (flake agglomerates) had different morphologies. The TEM image of LG-SiO2 revealed agglomerated ...
Added: June 4, 2026
Kornbleuth M., Opher M., Drake J. F. et al., Astrophysical Journal 2026 Vol. 1004 No. 1 Article 1
The shape of the heliosphere, regarded as comet-like since the 1960s, has recently been the subject of intense debate in the last decade. There is disagreement as to whether the heliospheric tail extends to ∼10,000 au in a comet-like shape or if it is short (∼400 au) with a split. Energetic neutral atom (ENA) maps from ...
Added: June 3, 2026
Nishant T., Kartsev A., Saswata G. et al., Journal of Materials Chemistry C 2026 Article -
Overheating remains a critical limitation in high-performance electronic and computing systems,
necessitating the development of efficient thermal management fluids. In this work, a magnetically
responsive hybrid ferrofluid was developed by incorporating two-dimensional hexagonal boron nitride
(2D-hBN) nanosheets into a Mn–Zn–ferrite-based ferrofluid. The hybrid system retains magnetic
responsiveness while leveraging the high in-plane thermal conductivity and chemical stability of 2D-hBN
nanosheets. ...
Added: June 2, 2026
Fortuna A. S., A.I. Kartsev, Gorshenkov M. V. et al., Journal of Alloys and Compounds 2026 Vol. 1070 Article 188711
The τ-phase in Mn-Al-Ga alloys is a promising candidate for rare-earth-free permanent magnets. This study re-veals that the τ(γ₂)-phase in rapidly quenched Mn55Al36Ga9 ribbons contains a high density of dislocations, which
form antiphase boundaries (APBs). Using transmission electron microscopy and density functional theory, we
demonstrate that Mn atoms at these APBs couple antiferromagnetically. This antiferromagnetic interaction is
identified ...
Added: June 2, 2026
Dikhtievskaya K., Argunov E., Alexey I. Kartsev et al., The Journal of Physical Chemistry Letters 2026 Vol. 17 No. 17 P. 4999–5004
In this study we revealed the effect of scandium doping on the electronic and superconducting properties of the MgB2 compound. Calculations demonstrate that Sc substitutes for Mg atoms, acting as an electron donor. Mg substitution diminishes the density of states in the σ-band and attenuates the electron–phonon coupling, thereby elucidating the reduction in critical temperature. Simultaneously, ...
Added: June 2, 2026
Duran E. ., Pulgar A., Izquierdo R. et al., Physica Status Solidi (A) Applications and Materials 2026 Vol. 223 No. 7 Article e202500942
Ceramic superconductors exhibit remarkable properties, including zero electrical resistance and potent magnetic behavior, operating at temperatures as high as the boiling points of liquid nitrogen (77 K) and liquid hydrogen (20 K). These characteristics position them as key enablers for sustainable technologies spanning electric propulsion, lossless energy transmission, advanced medical imaging, and quantum computation. This review presents ...
Added: June 1, 2026
Dorovskiy A., / Series arXiv "math". 2026.
In this paper the structural stability of generic families of vector fields of the PC-HC class on the two-dimensional sphere is proved. A classification of these families up to moderate equivalence in neighborhoods of their large bifurcation supports is presented, based on such invariants as the configuration and the characteristic set. The realization lemma is proved. ...
Added: May 14, 2026
Taletskii D., / Series arXiv "math". 2026.
A vertex subset of a graph is called a \textit{distance-$k$ independent set} if the distance between any two of its distinct vertices is at least $k + 1$. For all $n,k \geq 1$, we determine the minimum possible number of inclusion-wise maximal distance-$k$ independent sets among all $n$-vertex trees. It equals~$n$ if $n \leq k ...
Added: May 1, 2026
Ovcharenko M., / Series arXiv "math". 2026.
We introduce an explicit class of tempered Laurent polynomials in the sense of Villegas and Doran--Kerr in n⩽4 variables including all Landau--Ginzburg models for smooth Fano threefolds with very ample anticanonical class. We check that it contains Landau--Ginzburg models for various Fano fourfolds which are complete intersections in smooth toric varieties and Grassmannians of planes, ...
Added: April 30, 2026
Zlotnik Alexander, / Series arXiv "math". 2026. No. 2602.03481v1.
We deal with the global in time weak solutions to the 1D compressible Navier-Stokes system of equations for large discontinuous initial data and nonhomogeneous boundary conditions of three standard types. We prove the Lipschitz-type continuous dependence of the solution $(\eta,u,\theta)$, in a norm slightly stronger than $L^{2,\infty}(Q)\times L^2(Q)\times L^2(Q)$, on the initial data $(\eta^0,u^0,e^0)$ in a ...
Added: April 18, 2026
Medvedev V., / Series arXiv "math". 2026.
We investigate the interplay between the dimension of the space of static potentials and the geometric and topological structure of the underlying static three-manifold. A partial classification of boundaryless static manifolds is obtained in terms of this dimension. We also treat the case of static manifolds with boundary. In particular, we prove that if a ...
Added: April 3, 2026
Gabdullin N., Androsov I., / Series Computer Science "arxiv.org". 2026.
Label prediction in neural networks (NNs) has O(n) complexity proportional to the number of classes. This holds true for classification using fully connected layers and cosine similarity with some set of class prototypes. In this paper we show that if NN latent space (LS) geometry is known and possesses specific properties, label prediction complexity can ...
Added: April 2, 2026
Melnikov I., Flamarion M., Nonlinear Dynamics 2026 No. 114 Article 42
The interaction of a solitary wave with an external force is studied within the framework of a modified Korteweg-de Vries equation, accounting for viscosity and damping. Using asymptotic methods, a dynamical system is derived to describe the amplitude and phase of the solitary wave. A bifurcation analysis of this system is presented, depending on the ...
Added: February 24, 2026