Vortex-antivortex wavefunction of a degenerate quantum gas

A mechanism of a pinning of the quantized matter wave vortices by optical vortices in a specially arranged optical dipole traps is discussed. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum and form the "antiferromagnet"-like matter waves. The separable Hamiltonian for matter waves in pancake trapping geometry is proposed and 3D-wavefunction is factorized in a product of wavefunctions of the 1D harmonic oscillator and 2D vortex-antivortex quantum state. The 2D wavefunction's phase gradient field associated via Madelung transform with the field of classical velocities forms labyrinth-like structure. The macroscopic quantum state composed of periodically spaced counter-rotating BEC superfluid vortices has zero angular momentum and nonzero rotational energy.Comment: 11 pages, 5 figure

Experimental observation of spontaneous spin polarization of electrons in hybridized states of transition element impurities in semiconductors

Experimental evidence of the possible existence of spontaneous spin polarization of the electron system in hybridized states formed by transition element impurity atoms in the conduction band of semiconducting crystals is examined. The details of a quantitative interpretation of experiments on the temperature dependence of the specific heat and elastic moduli of mercury selenide crystals with iron impurities confirm the feasibility of establishing the presence of electron spin polarization in this type of experiment, as well as the possible existence of polarization in the crystals studied here. Theoretical arguments support the observation of a thermodynamic anomalous Hall effect owing to spontaneously polarized donor electrons from low-concentration impurities. © 2013 AIP Publishing LLC

Magnetization in AIIIBV semiconductor heterostructures with the depletion layer of manganese

The magnetic moment and magnetization in GaAs/Ga$_{0.84}$In$_{0.16}$As/GaAs heterostructures with Mn deluted in GaAs cover layers and with atomically controlled Mn $\delta$-layer thicknesses near GaInAs-quantum well ($\sim$3 nm) in temperature range T=(1.8-300)K in magnetic field up to 50 kOe have been investigated. The mass magnetization all of the samples of GaAs/Ga$_{0.84}$In$_{0.16}$As/GaAs with Mn increases with the increasing of the magnetic field that pointed out on the presence of low-dimensional ferromagnetism in the manganese depletion layer of GaAs based structures. It has been estimated the manganese content threshold at which the ferromagnetic ordering was found.Comment: 8 pages, 3 figure

Surface functionalization of biomedical Ti-6Al-7Nb alloy by liquid metal dealloying

Surface functionalization is an effective approach to change the surface properties of a material to achieve a specific goal such as improving the biocompatibility of the material. Here, the surface of the commercial biomedical Ti-6Al-7Nb alloy was functionalized through synthesizing of a porous surface layer by liquid metal dealloying (LMD). During LMD, the Ti-6Al-7Nb alloy is immersed in liquid magnesium (Mg) and both materials react with each other. Particularly, aluminum (Al) is selectively dissolved from the Ti-6Al-7Nb alloy into liquid Mg while titanium (Ti) and niobium (Nb) diffuse along the metal/liquid interface to form a porous structure. We demonstrate that the porous surface layer in the Ti-6Al-7Nb alloy can be successfully tailored by LMD. Furthermore, the concentration of harmful Al in this porous layer is reduced by about 48% (from 5.62 ± 0.11 wt.% to 2.95 ± 0.05 wt.%) after 30 min of dealloying at 1150 K. The properties of the porous layer (e.g., layer thickness) can be tuned by varying the dealloying conditions. In-vitro tests suggest improved bone formation on the functionalized porous surface of the Ti-6Al-7Nb alloy. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.European Research Council, ERCTohoku UniversityMinistry of Science and Higher Education of the Russian FederationNanjing University of Science and Technology, NUST: K2-2020-020MA 3333/13-1Supervision, I.V.O., R.W.-R., L.Z., L.M., J.E. and H.K.; Validation, I.V.O., S.-H.J., and B.L.; Writing – original draft, I.V.O. and B.L.; Writing – review & editing, all. All authors have read and agreed to the published version Funding: The financial support was provided by the German Science Foundation under the Leibniz Program of the manuscript. (Grant MA 3333/13-1), by the European Research Council (ERC) under the ERC Advanced Grant INTELHYB (grant Funding: The financial support was provided by the German Science Foundation under the Leibniz Program Ministry of Science and Higher Education of the Russian Federation, in the framework of the Increase Competitiveness (Grant MA 3333/13-1), by the European Research Council (ERC) under the ERC Advanced Grant INTELHYB Program of NUST «MISiS» (grant number K2-2020-020). I.V.O. is grateful for the financial support provided by the International Collaboration Center, Institute for Materials Research (ICC-IMR), Tohoku University, Japan. 02.A03.21.0006), and the Ministry of Science and Higher Education of the Russian Federation, in the framework Conflicts of Interest: The authors declare no conflict of interest. of the Increase Competitiveness Program of NUST «MISiS» (grant number K2-2020-020). I.V.O. is grateful for the financial support provided by the International Collaboration Center, Institute for Materials Research (ICC-IMR), Tohoku University, Japan

Simulaling the Faceted Tube Drawing

The paper studies cold-sinking of four-, six-, and eight-faceted steel tubes from round billets in a single pass. The built mathematical model of the process objectively describes the drawing and allows forecasting the geometric and deformation parameters of the pipes processed, as well as the power parameters of the process. The model accuracy has been confirmed by a series of parallel calculations and a comparative calculation in two software packages. The results have shown satisfactory convergence. The theoretical experiment results have been verified by performing a full-scale one. The results have also been consistent. The research results are of practical use to the process equipment manufacturers and consumers. © Published under licence by IOP Publishing Ltd.The work was performed according to the State task of the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences in the framework of the Program of Basic Research of State Academies. The work was supported by the Russian Foundation for Basic Research (project No. 20-21-00063 Rosatom) according to the State Assignment of IMET UB RAS under the Program of Fundamental Research of State Academies

Quantum Billiards with Surface Scattering: Ballistic Sigma-Model Approach

Statistical properties of energy levels and eigenfunctions in a ballistic system with diffusive surface scattering are investigated. The two-level correlation function, the level number variance, the correlation function of wavefunction intensities, and the inverse participation ratio are calculated.Comment: 4 pages REVTEX, two figures included as eps file

Strength Low Modulus Ti–Fe-Based Materials with Open Porous Microstructure for Biomedical Applications

Настоящая работа посвящена исследованию сквозных пористых Ti–Fe сплавов, синтезированных методом деаллоинга в жидком Mg исходного сплава Ti–Fe–Cu с использованием нескольких параметров процесса деаллоинга. Подробные результаты исследования опубликованы в работе [1].The present work is concerned with the research of open porous Ti-Fe alloys synthesized by dealloying in liquid Mg of the initial Ti-Fe-Cu alloy using several parameters of the dealloying process. Detailed results of the research are published in [1].Работа выполнена в рамках государственного задания Минобрнауки России (тема «Лазер», № АААА–А19–119070490049–8).The work was carried out within the framework of the state assignment of the Ministry of Education and Science of Russia (topic “Laser”, № AAAA19–119070490049–8)

Plasma Jet Stream Simulation for Formation Coating and Powder Manufacturing Processes

To carry out a comparative analysis of the parameters of the plasma jet flow, the configurations of the plasmatrons that are most common in industrial practice have been selected. The values of temperature, velocity and intensity of turbulence at the characteristic point are determined depending on the shape of the components of the plasmatrons. Recommendations have been developed for the configuration of technological equipment used in the processes of coating and powder production. © Published under licence by IOP Publishing Ltd.The work was performed according to the State task of the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences in the framework of the Program of Basic Research of State Academies. The work was supported by the Russian Foundation for Basic Research project No. 20-21-00063 (Rosatom)

PIV study of the effect of piston position on the in-cylinder swirling flow during the scavenging process in large two-stroke marine diesel engines

A simplified model of a low speed large two-stroke marine diesel engine cylinder is developed. The effect of piston position on the in-cylinder swirling flow during the scavenging process is studied using the stereoscopic particle image velocimetry technique. The measurements are conducted at different cross-sectional planes along the cylinder length and at piston positions covering the air intake port by 0, 25, 50 and 75%. When the intake port is fully open, the tangential velocity profile is similar to a Burgers vortex, whereas the axial velocity has a wake-like profile. Due to internal wall friction, the swirl decays downstream, and the size of the vortex core increases. For increasing port closures, the tangential velocity profile changes from a Burgers vortex to a forced vortex, and the axial velocity changes correspondingly from a wake-like profile to a jet-like profile. For piston position with 75% intake port closure, the jet-like axial velocity profile at a cross-sectional plane close to the intake port changes back to a wake-like profile at the adjacent downstream cross-sectional plane. This is characteristic of a vortex breakdown. The non-dimensional velocity profiles show no significant variation with the variation in Reynolds numbe