bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristic properties of “spin glass” alloys of copper with manganese and cobalt
Authors: Vedyaev A. V. , Cherenkov V. A.
Published: December 2024

The electrical resistivity, the thermo-emf, the magnetic susceptibility in an alternating magnetic field, the Hall effect, and the electron–paramagnetic resonance in copper–manganese and copper–cobalt alloys were studied over the 4.2–300 °K temperature range. Here the main parameters of these systems, namely the s–d exchange integrals and the effective Kondo temperatures as well as the magnitudes of impurity–impurity and RKKY interaction are calculated. The anomalies found in the kinetic characteristics are attributed to a transition of these systems to the “spin glass” state.
Exciton relaxation in condensed xenon
Authors: Voronova T. Ya. , Obodovskii I. M.
Published: December 2024

We have studied the kinetics and luminescence yield of alpha scintillation in liquid and solid xenon and in the gas at high pressures, up to the critical pressure. The changes in these parameters were followed through the phase transitions. A kinetic model has been formulated which takes into account the transitions between the low excited states of Xe2. We found the effective lifetime of the triplet level to be τ2 = 90 ± 10 nsec, the difference in energy levels to be ΔE = (3.4 ± 1.7) meV, the probability for transitions between them to be 1∑u+⇄k2k1∑u+k1=(4.1±1.5)⋅10−14cm3/sec and k2 = (1.37±0.5)× 10−14 exp (– ΔE/kT) cm3/sec. We observed that the relaxation parameters are identical in the Xe2∗ molecule and in the exciton state.
The dispersion law of crystallization-melting waves at a quantum crystal surface
Authors: Kosevich A. M. , Kosevich Yu. A.
Published: December 2024

Attention is drawn to the fact that the crystallization-melting wave may be represented as directed motion of a large number of growth steps at the quantum crystal surface. The dynamics of steps is considered, and the effective mass of an individual step is calculated. A correction is found to the dispersion law of Andreev Parshin surface waves.
A type-II superconductor in a variable field
Authors: Krasnov Yu. K.
Published: December 2024

The impedance in an ac circuit of a type-II superconductor in the vortex state is studied within the framework of the phenomenological theory of the motion of quantized vortices. It is suggested that such a superconductor can be used as the element that generates the master feedback signal in radio-frequency ac generators. The phase diagram of such generators is considered. A new method of measuring the electrodynamic parameters of type-II superconductors in the mixed state is proposed.
Critical current anisotropy and the peak effect in plastically deformed superconducting single crystal niobium
Authors: Vinnikov L. Ya.
Published: December 2024

The critical currents and the dislocation structure of a deformed niobium single crystal are investigated. The critical current as a function of the angle of inclination of the magnetic field to the broad face of a plane sample is found to be anisotropic. The critical currents exhibit a complex correlation with the anisotropic dislocation distribution.
Localized superconducting states in spatially inhomogeneous superconductors
Authors: Nabutovskii V. M. , Shapiro B. Ya.
Published: December 2024

The temperature at which localized superconducting states appear in metals with an inhomogeneous electron-electron interaction constant g(r) is determined as a functional of the inhomogeneity parameters. Planar, linear, and volume inhomogeneities are considered within the framework of the microscopic theory of superconductivity both for the case g(r) → g(∞) ≠ 0 and for g(r) → g(∞) = 0, when the inhomogeneity is the sole source of the superconductivity. The inhomogeneities described can serve as a model of grain boundaries, dislocation tubes, and inhomogeneous clusters of impurity atoms.
Electronic structure of hexagonal ferromagnetic cobalt and its change under pressure
Authors: Kulikov N. I. , Kulatov É. T.
Published: December 2024

Self-consistent computations of the band structure of hexagonal-close-packed (hcp) ferromagnetic cobalt under normal conditions and a pressure of 290 kbar are performed. The linearized Korringa-Kohn-Rostoker method (model Hamiltonian) is used for the computation. Results of the computation are compared with recent experimental investigations of the band structure by the method of photoelectron spectroscopy. A new model is presented for the Fermi surface of this metal, which permits incontrovertible description of both the angular dependences of the frequency spectrum of the de Haas–van Alphen effect, and their change under pressure.
Effect of dissolved hydrogen on electrical properties of low-temperature tin films
Authors: Belevtsev B. I. , Komnik Yu. F.
Published: December 2024

A study was made to determine the effect of dissolved hydrogen on the electrical and superconducting properties of tin films deposited on a substrate cooled by liquid helium, with hydrogen at pressures of (1–9) · 10−5 torr present in the ambient vacuum. It has been found that dissolved hydrogen does strongly affect the electrical and superconducting properties of tin films, namely it causes an appreciable increase of their electrical resistance (by 1–2 orders of magnitude) and superconducting transition temperature Tc (by approximately 1 °K). The effect of hydrogen increases with its concentration and with decreasing thickness of the films. Furthermore, the R(T) curve of irreversible changes was found to have a minimum at about 25 °K evidently associated with an escape of dissolved hydrogen from the films. These results are discussed here on the basis of known theoretical concepts.
Peierls insulator with induced dimerization and soliton confinement
Authors: Krive I. V. , Rozhavskii A. S.
Published: December 2024

The conduction mechanism in a Peierls insulator (PI) of the cis-polyacetylene type is investigated. It is shown that depending on the magnitude of the external electric field and the parameter γ ≅ Δe/ Δ0 (Δo is the “rigid” gap in the conduction electron spectrum, owing to induced dimerization, Δω is the equilibrium PI gap for Δe = 0), two qualitatively different types of conductivity are realized in the PI: polaron and soliton conductivity, as well as an insulating phase, in which solitons are confined and which is characterized by a large number of quantum soliton–antisoliton levels. The analogy between the PI with induced dimerization and one-dimensional quantum electrodynamics (massive Schwinger model) is noted.
The absorption of high-frequency energy in three-magnon processes in a quasi-one-dimensional ferromagnet
Authors: Pereverzev Yu. V.
Published: December 2024

We calculate the absorption coefficient of high-frequency energy in a quasi-one-dimensional ferromagnet. In processes with the participation of three magnons, the high density of magnon states in the low-energy part of the spectrum results in considerable losses of electromagnetic radiation with frequencies close to the limiting values of the magnon energy in the direction of strong exchange interaction. The obtained results are applicable to quasi-one-dimensional antiferromagnets which consist of ferromagnetic chains coupled by a weak antiferromagnetic interaction.
Static skin effect in a magnetic field oriented obliquely to the plate surface
Authors: Kopeliovich A. I.
Published: December 2024

The thickness-averaged electrical conductivity of a plate of a typical metal with an atomically smooth surface and of a plate of a semimetal in a magnetic field oriented obliquely to the plate surface is examined, as is also the consequences of the skin effect for the current under these conditions. The conditions are established under which multichannel specular reflection of electrons by the surface appreciably influences the electrical conductivity and can thus be detected experimentally. In a plate of a semimetal there is demonstrated the existence of two skin-effect layers and the transition is tracked which occurs as the field inclination angle changes from the diffuse size effect to one corresponding to the static skin effect, a transition also characteristic of a typical metal.
Electron-phonon interaction and x-ray emission spectra of osmium in the relativistic approximation
Authors: Nemoshkalenko V. V. , Antonov V. N. , Antonov VI. N.
Published: December 2024

The energy band structure and wave functions of osmium are calculated using the method of relativistic augmented plane waves. The potential was determined by superposition of Slater atomic charge densities with exchange with α = 1. The total and partial densities of states were computed with the use of a linear interpolation scheme. The intensity distribution in the OIIINVI,VII emission spectrum is computed in the dipole approximation. The Hopfield parameter η is computed. The numerical results showed that relativistic effects are important. However, the effect of spin orbital interaction on the magnitude of the electron-phonon interaction is insignificant.
The relation between the structure and electrophysical properties of niobium nitride films
Authors: Antonova E. A. , Sukhov V. A.
Published: December 2024

A study is made of the microstructure, lattice constant, electrophysical properties (residual resistivity ρ, the ratio ρ300/ρ20, Tc, ΔTc) of niobium nitride films prepared by the reactive cathode sputtering technique, with the composition varying regularly within the existence domain of the cubic δ-NbN phase. The sputtered niobium nitride films are shown to have a columnar-granular structure. The degree of granulation is determined by the technological parameters of their preparation, i.e., the composition of the gas mixture and the substrate temperature, and by the character of the film structure and grain size. The critical temperature of niobium nitride films is governed by the composition of the grains and the degree of granulation of the structure.
Effect of localized electron-magnon states on magnetic ordering in doped ferromagnetic semiconductors
Authors: Petrova T. G.
Published: December 2024

Localized electron-magnon states, arising below the continuous spectrum of a ferromagnetic semiconductor with a donor impurity having a magnetic moment is studied with the use of the microscopic s-d model. Impurity states in which electron localization at a defect is accompanied by a different number of spin deviations from the direction of magnetic ordering are examined. The energies and average values of the z projection of the impurity spin in such states are found, using the Jacobi matrix method, for different values of the parameters describing the s-d exchange interaction of an electron with a defect and with a regular atom. The structure of the energetically most favorable electron-magnon impurity states is determined. It is shown that it depends greatly on the nature of the s-d interactions in the system. The study carried out permits a systematic explanation of the different effect of donors, observed experimentally, on the magnetic ordering of ferromagnetic semiconductors.
Energy spectrum of CsDy(MoO4)2 in vicinity of the structural phase transition
Authors: Khats’ko E. N. , Chernyi A. S.
Published: December 2024

The magnetic susceptibility of CsDy(MoO4)2 and CsDy(MoO4)2 + 10% Eu3+ was measured in the temperature range 4—70 °K and the frequency range 200 Hz-20 MHz. The spin-lattice relaxation of the Dy3+ ion observed in this case is characterized by exponential temperature dependences of the relaxation time: τ−1 = A exp(—Δ/kT) with Δ = 105±20 cm−1 and 250±40 cm−1 for CsDy(MoO4)2 in the temperature ranges 10–20 and 20–38 °K, respectively, and Δ = 22.4± 5 cm for CsDy(MoO4)2 + 10% Eu3+. It is postulated that the energies Δ = 105±20 cm and 250±40 cm correspond to the first and second excited levels of Dy3+ in the low-temperature phase of CsDy(MoO4)2, while Δ = 22.4 ± 5 cm-1 corresponds to the first excited level of Dy3+ in the high-temperature phase of this compound.
Electron photoferromagnetism in ferromagnets
Authors: Genkin G. M. , Tokman I. D.
Published: December 2024

The change in magnetization of a ferromagnet due to the contribution of spin polarized carrier magnetism is considered. Such electronic photoferromagnetism occurs upon the absorption of light whose frequency satisfies the condition Eg <ħω <Eg + AS (Eg is the forbidden bandwidth, and AS is the magnitude of spin splitting of the conduction band).
Phase transition in a weakly disordered quasi-one-dimensional magnet material
Authors: Kleiner V. Z. , Makarov V. I.
Published: December 2024

The effect of fixed substitutional impurities on the magnetic field driven phase transition is considered in the one-dimensional X-Y model. It is shown that in the low-concentration region smearing of the singularity in the magnetic susceptibility is significantly attenuated when the relation (I′/I)2=/ μ′/μ is satisfied for the exchange constants and magnetons of the impurities and of the matrix.
High-frequency conductivity of superconducting gallium according to ultrasonic data
Authors: Denisenko V. I. , Fil’ V. D. , Masalitin E. A. , Bezuglyi P. A.
Published: December 2024

The high-frequency conductivity of superconducting gallium near the transition temperature is determined from measurements of the complex propagation constant of linearly polarized transverse sound. It is shown that the normalized complex conductivity in the investigated frequency range (50–250 MHz) is practically independent of the frequency, and its temperature variation is consistent with the theoretical calculations.
Nonlinear acoustic phenomena in superconductors with paramagnetic impurities
Authors: Galaiko V. P. , Glushchuk N. I. , Shumeiko V. S.
Published: December 2024

Effects on paramagnetic impurities on the nonlinear attenuation of short-wavelength longitudinal sound and on generation of acoustic harmonics in pure superconductors are considered. The acoustic nonlinearity results from strong nonequilibrium of the electron system which is formed due to Andreev’s mechanism for the dragging of resonance excitations by the sound wave field.
Observation of the Shubnikov–de Haas effect in thin bismuth films
Authors: Komnik Yu. F. , Andrievskii V. V. , Butenko A. V.
Published: December 2024

Through recording of the derivative ∂R/∂H as a function of the magnetic field intensity H over the 0–50 kOe range at 4.2 °K in epitaxial 1300–4000-Å-thick bismuth films, it was possible to detect Shubnikov-de Haas oscillations corresponding to magnetic quantization in the hole band. Large-amplitude Shubnikov-de Haas oscillations were observed in the field dependence of the derivative ∂VH/∂H and of the Hall component VH+,VH− itself directly, which has been found to be another manifestation of magnetic quantization in the hole band. The period of all observed Δ(H−1) oscillations was found to vary appreciably with varying film thickness L, namely to decrease from ∼3 · 10−5 Oe−1 at the maximum thickness to 1.8 · 10−5 Oe −1 at 1500 Å, while remaining larger than the corresponding known period (1.6 · 10−5 Oe−1) for holes in a pure bulk bismuth crystal with an analogous orientation of the crystallographic axes. The decrease of the Δ(H−1) period with decreasing film thickness L corresponds to the result, obtained earlier with with the aid of measurements of kinetic characteristics of a bismuth film, that indicates an increase in the concentrations of both types of charge carriers with a decrease in the bismuth film thickness, and is explainable on the basis of the model of a nonuniform film potential.
Effect of isovalent impurities and pressure on the magnetic properties and the parameters of the energy spectrum of cadmium
Authors: Grechnev G. E. , Svechkarev I. V.
Published: December 2024

The behavior of the magnetic susceptibility of a cadmium single crystal upon introduction of isovalent impurities and under pressure at low temperatures (T≃20°K) is analyzed on the basis of an earlier constructed theory of magnetism in normal hcp metals. The effect of impurity scattering on the anomalies of the magnetic susceptibility are taken into account in terms of the effective temperature, which can be determined experimentally. Through a comparison of the calculated magnetic susceptibility with experimental data, there have been determined several energy-spectrum parameters of pure cadmium as well as the dependence of the band splitting and of the position of the level of the chemical potential on the concentration of magnesium and mercury impurities and on the applied pressure. Quantitative characteristics of the pseudopotential of cadmium near the first zero of the form factor have been obtained in the “on the Fermi sphere” approximation.
Anisotropy of electrical resistivity of osmium single crystals from 4.2-300 °K
Authors: Volkenshtein N. V. , Dyakina V. P. , Dyakin V. V. , Startsev V. E. , Cherepanov V. I. , Azhazha V. M. , Kovtun G. P. , Elenskii V. A.
Published: December 2024

The anisotropy of the electrical resistivity of pure osmium single crystals with ρ273.2/ρ4.2 = 2600 has been studied at temperatures of 4.2–300 °K. In addition, the anisotropy of the size effect was studied at 4.2 °K. It was observed that the resistivity anisotropy coefficient α(T)=ρ〈0001〉/ρ〈101¯0〉 is smaller than unity and has a maximum at T≈50 °K. The anisotropy in the size effect (ρl)〈0001〉/(ρl)〈1010¯〉 is 0.39±0.07 at 4.2 °K. At helium temperatures scattering of conduction electrons by the crystal surface radically alters ρ(T) in thin samples. The results are interpreted based on the geometry of the Fermi surface in osmium and including the electron-phonon relaxation processes and electron scattering at the sample surface.
Vibrations of a string in a superfluid liquid
Authors: Gabdulin V. Z. , Krasnov Yu. K.
Published: December 2024

The spectrum and the relaxation time of harmonics of the free vibrations of a quantized Onsager–Feynman vortex, both isolated and attached to a thin string are studied. It is demonstrated that a systematic application of the dynamic theory of quantized vortices yields a new temperature dependence of the beat frequency for such a string and the quantized vortex attached to it. New possibilities are considered which illustrate how the vibrations of a string with Onsager–Feynman vortex attached can be used for studying the quantum properties of helium-II.
Amplitude-dependent damping of axial–torsional oscillations of a cylinder of the alloy AI–13.5 at.% Ag
Authors: Magradze O. V.
Published: December 2024

The damping of oscillations of cylinders made of the superconducting alloy Al–13.5 at.% Ag was investigated. It was established that under different heat treatment a defect structure consisting of spherical Guinier-Preston zones and individual γ′-phase lamellae was formed in one specimen while in another specimen it was an ordered structure of γ′-phase lamellae along with the equilibrium γ-phase. With a decrease in the amplitude of the oscillations in magnetic fields relatively far from the lower critical field, the damping at first increases, reaches a maximum, and then decreases as the amplitude continues to decrease. With the growth of the magnetic field the damping maximum shifts to lower amplitudes. The concentration Cp of pinned fluxoids (in relation to the total number of fluxoids in the specimen) was found from the magnetization curves and from data on the oscillation frequency of the specimen. It was discovered that in each case the damping maximum is observed at Cp ∼0.5, i.e., when roughly half of the fluxoids are pinned and the other half are free.
Influence of the type of impurity on the scattering of conduction electrons in niobium and vanadium at 20.4 °K
Authors: Aleksandrov B. N. , Dalakova N. V. , Slobodskoi M. I. , Filippov V. F.
Published: December 2024

The effects of six impurities (Ti, Fe, Co, Ni, Cu, Mo) on the residual resistivity of vanadium and of eleven impurities (Al, Si, Ti, V, Cr, Cu, Zr, Mo, Pd, Hf, W) on the residual resistivity of niobium have been investigated. For the series of impurities the value of the change of residual resistivity of the alloys Δρ/c for 1 at.% added impurity has been obtained for the first time. It has been established that for V- and Vi-period impurities in niobium the quantity Δρ/c has a maximum in the vicinity of Ru and Os, respectively. For IV- period impurities in vanadium a monotonic growth of Δρ/c occurs from vanadium to copper. Up to now there is no theoretical explanation of this phenomenon.
High-frequency properties of copper chloride dihydrate over a wide range of frequencies and magnetic fields
Authors: Galkin A. A. , Vetchinov A. V. , Dan’shin N. V. , Popov V. A.
Published: December 2024

The antiferromagnetic resonance in CuCl2 · 2H2O is studied experimentally and theoretically over a wide range of values of the magnetic field H||a. New values of the characteristic fields and other parameters of this antiferromagnet, differing from the values obtained in other works, are determined. The influence of the predicted weak ferromagnetism on the resonance properties of CuCl2 · 2H2O was not observed.
Phonon damping of excitons in cryocrystals of inert elements
Authors: Fugol’ I. Ya. , Tarasova E. I.
Published: December 2024

The damping Γk(T) and nonadiabtic displacement of excitonic states in cryocrystals of inert elements with single phonon scattering are studied over a wide range of temperatures and values of exciton quasi-momenta. A detailed analysis of the different limiting situations (with respect to temperature and magnitude of the quasimomentum) is carried out and calculations of the damping of the exciton states are presented in analytic form. For purposes of practical application and checking the applicability of the theoretical approximations, the results of an exact numerical calculation of Γk(T) are examined. It is shown that excitons remain “good” quasiparticles only for temperatures that do not exceed a critical value Tc and quasimomenta that are greater than some limiting values k0 (T). The nature of the change in damping as a function of the magnitude of the exciton wave vector is analyzed in detail. It is established that taking into account nonadiabatic exciton-phonon interactions lowers the exciton states by several Debye frequencies.
Acoustic doppleron-spin resonance in metals
Authors: Zvezdin M. K.
Published: December 2024

The possibility of exciting magnetic resonance of the nuclear spin system of a metal by phonons by exciting the doppleron-phonon resonance at the NMR frequency is shown. A condition is obtained for the existence of this effect and possibilities for its observation are discussed.
Growth step formed by an edge dislocation emerging on a crystal surface
Authors: Kosevich A. M. , Kosevich Yu. A.
Published: December 2024

The elastic field an edge dislocation near the free surface of a crystal is described. It is shown that the treatment suggested is consistent with the description of a growth step on the crystal surface.
Multiphoton absorption by Fermi systems with pulsed and continuous pumping
Authors: Glazman L. I. , Tsukernik V. M.
Published: December 2024

The magnitude of the absorption of a strong alternating field interacting parametrically with a system of Fermi particles is calculated. The cases of pulsed action of the field on the system and continuous pumping, establishing a state of saturation, are examined. The equations obtained are applied to the problem of longitudinal pumping in a one-dimensional XY spin model and to the theory of interband absorption of a strong electromagnetic wave.
Weak ferrimagnetism in CsMnF3: polarization spectroscopic and visual investigations
Authors: Eremenko V. V. , Mil’ner A. A. , Kharchenko N. F. , Gredeskul V. M. , Popkov Yu. A. , Petrov S. V.
Published: December 2024

Using polarization spectroscopy, a weak uncompensated magnetic moment directed along the hexogonal axis is shown to exist in a CsMnF3 crystal. The magnitude of the moment is estimated as mz ≲ 0.2 cgsm/cm3. The weak ferrimagnetic domains (WFM) in the specimen were photographed in quasimonochromatic light with a wavelength corresponding to the exciton absorption line.
Structure of thin films of solidified N2–Xe and N2–Kr binary mixtures
Authors: Kovalenko S. I. , Krupskii I. N. , Solodovnik A. A.
Published: December 2024

The structure of solidified N2–Xe and N2–Kr mixtures was studied by transmission electron diffraction. Observations were carried out in the temperature range from 2.5 to 30 °K on specimens prepared at 2.5, 20, 25, and 28 °K by condensation from the gas phase. The influences of composition, deposition temperature, and also of subsequent heating on the structure of the condensates were established. The form of the phase diagrams of the systems studied was deduced from an analysis of the experimental results. It was shown that the orientational order of the N2 molecules is destroyed as the inert gas content is increased. The observed disorientation occurred in the process of forming the specimens from the gas phase.
Probability of two-phonon scattering of polaritons in xenon cryocrystals
Authors: Fugol’ I. Ya. , Tarasova E. I.
Published: December 2024

We have studied the properties of the intensity distribution and the structure of the resonance band in the polariton luminescence in solidified xenon. The existence of an additional maximum in the emission at low temperatures (T < 10 °K) is related to the presence of anomalies at the corresponding frequency in the two-phonon Raman scattering probability, while the symmetrization of the resonance band for T >60°K is explained by thermal activation of two-phonon scattering of polaritons by acoustic phonons at this temperature.
The temperature dependence of the domain structure in thulium orthoferrite
Authors: Gorobets Yu. I. , Lapchenko V. F. , Prokopenko A. K. , Khokhlov V. A.
Published: December 2024

The domain structure of thulium orthoferrite in the spontaneous spin-flip region of Fe3+ ions has been studied. The domain structure, which is a maze structure at room temperature, becomes a strip structure in the spin-flip region T2–T1 (T2 is the beginning and T1 is the end of the transition). As the temperature is raised from T1 the strip-domain structure is preserved up to roughly 150 °K, after which bubbles appear along with the strip structure. It is suggested that the observed change in the domain structure during the spin-flip phase transition is caused by the presence of a potential barrier between the strip and maze structures, owing to the difference of the magnetostatic energies of the two structures. The domain-wall energy σw(T) and the anisotropy constant K1 (T) are found as a function of the temperature from the temperature dependence of the period of the strip-domain structure.
Spectrum of elementary excitations with spin reorientation in ferromagnets
Authors: Bar’yakhtar V. G. , Grishin A. M. , Drobot’ko V. F.
Published: December 2024

An essential difference between spin reorientation in ferromagnetic metals and insulators is demonstrated. At low frequencies the spectrum and wave transformations are affected mainly by the interaction of magnetic oscillations with the slow wave of minimum phase velocity. In insulators this is the magnetoacoustic interaction, in metals it is the coupling of magnons to damped electromagnetic oscillations.
Approximation of P–ρ–T data near the critical point for He4 with a new equation of state
Authors: Kukarin V. F. , Martynets V. G. , Matizen É. V. , Sartakov A. G.
Published: December 2024

P–ρ–T data for He4 obtained near its critical evaporation point are approximated with a new equation of state which takes into account the asymmetry of real liquids as well as the nonasymptotic behavior of liquids farther away from the critical point. It is demonstrated that the terms in this equation which describe the nonasymptotic behavior become significant at the 0.99 confidence level. The results of this approximation are compared with data of other authors.
Electric field in a superconducting ring
Authors: Kon L. Z. , lordatii V. P.
Published: December 2024

An equation describing the spatial distribution of the gauge invariant potential for a current-carrying superconductor in the presence of a temperature gradient along the current is derived on the basis of the kinetic equations. The electric field and the heat flux in a bimetallic ring are computed with the aid of this equation. The pure-superconductor limit, in which the electrons are scattered not only by the phonons, but also by the magnetic impurities or the nonmagnetic impurities when the condensate velocity is nonzero, is considered.
Vibrations of an edge dislocation in a ferromagnet
Authors: Bar’yakhtar V. G. , Sobolev V. L. , Khudik B. I.
Published: December 2024

The influence of the vibrations of an edge dislocation in a ferromagnet on the magnetization dynamics is studied. Expressions are obtained for the Fourier components of the variable part of the magnetization and the elastic displacement vector. The energy flux emitted by the dislocations and the radiation damping of its vibrations are computed.
Effect of magnetic fields of up to 62 kOe on the yield strength of aluminum
Authors: Krylovskii V. S. , Lebedev V. P. , Khotkevich V. I.
Published: December 2024

The yield strength of polycrystalline aluminum of 99.9999–99.5% purity at 4.2 °K was measured in a longitudinal magnetic field of up to 62 kOe. It has been found that the yield strength of aluminum increases with increasing magnetic field intensity and with increasing strain rate, and also depends on the chemical and structural purity of the metal. The results obtained are discussed on the basis of models of electron-induced dislocation drag in a magnetic field.
Advances in synchronization and superstimulation for OPU/IVEP: optimizing oocyte quantity and quality
Authors: Motta Jessica C. L. , Hayden Cameron B. , Sala Rodrigo V. , Ross Pablo J. , García-Guerra Alvaro
Published: December 2024

The sustained expansion of in vitro embryo production (IVEP) in cattle necessitates ongoing advancements in IVEP methodologies. The success of IVEP largely depends on the quantity and quality (i.e. developmental competence) of oocytes retrieved after ovum pick-up (OPU). The fundamental role of the ovarian follicle in the development of the oocyte highlights the importance of considering the ovarian physiology during development of OPU/IVEP methodologies. Oocyte quantity is largely influenced by ovarian phenotype determined through antral follicle count (AFC) or circulating anti-Müllerian hormone (AMH). In addition, substantial evidence indicates that follicle size and status can affect OPU/IVEP outcomes such that promoting the presence of medium to large sized dominant-like follicles can enhance oocyte developmental competence and thus embryo production. Ovarian superstimulation, using follicle-stimulating hormone (FSH), allows optimization of follicle development and oocyte developmental competence resulting in greater IVEP efficacy. The present review examines various aspects of FSH administration, providing an update of ovarian superstimulation methodologies and their implementation in OPU/IVEP systems. Additionally, the potential development of targeted ovarian superstimulation approaches that consider the marked physiological differences among individuals with varying AFC/AMH phenotypes is explored with the goal of further enhancing IVEP efficacy.
Molecular basis of lipid and ligand regulation of prostaglandin receptor DP2
Authors: Xu Jiuyin , Xu Youwei , Hou Li , He Xinheng , Li Yang , Zhao Jing , Meng Xue , Wang James Jiqi , Wu Yanli , Zhang Heng , Li Yunhai , Hu Wen , Yuan Qingning , Wu Kai , Cheng Xi , Jiang Yi , Xia Yu , Xu H. Eric , Wu Canrong
Published: December 2024

Prostaglandin D2 receptor 2 (DP2) is an important anti-inflammatory and antiallergic drug target. While inactive DP2 structures are known, its activation mechanisms and biased signaling remain unclear. Here, we report cryo-EM structures of an apo DP2–Gi complex, a DP2–Gi complex bound to the endogenous ligand Prostaglandin D
2
(PGD
2
), and a DP2–Gi complex bound to indomethacin, an arrestin-biased ligand, at resolutions of 2.5 Å, 2.8Å, and 2.3 Å, respectively. These structures reveal a distinct binding pose of PGD
2
and indomethacin and provide key insights into receptor activation and transducer coupling. Combining the structural data with functional studies, we uncover the molecular basis for biased signaling of indomethacin toward β-arrestin over G proteins. Notably, a phospholipid binding site was identified at the DP2–G protein interface that modulates DP2–G protein interactions. Together, our functional and structural findings provide insights into DP2 activation, biased signaling, drug interactions, and lipid regulation, enabling rational design of safer antiallergy therapeutics targeting this key immune receptor.
3D electron microscopy for analyzing nanoparticles in the tumor endothelium
Authors: Mladjenovic Stefan M. , Chandok Ishaan S. , Darbandi Ali , Nguyen Luan N. M. , Stordy Benjamin , Zhen Mei , Chan Warren C. W.
Published: December 2024

Delivering medical agents to diseased tissues has been challenging, leading researchers to study the in vivo transport process in the body for improving delivery. Many imaging techniques exist for mapping the distribution of medical agent-carrying nanoparticles in tissues, but they cannot capture the three-dimensional context of tissues with single nanoparticle resolution. Here, we developed 3DEM-NPD, a three-dimensional electron microscopy (3D EM) machine learning strategy to image and map single nanoparticle distributions (NPD) in tissues. 3DEM-NPD provides unbiased visualization and quantification of individual nanoparticles within organs. We applied this technique to quantify nanoparticle transport through tumor blood vessel endothelial cells. We measured the cell diameter, surface area, and volume and found that traditional 2D EM cannot accurately measure these features. We used machine learning to locate over 550,000 nanoparticles in less than 3 h with an accuracy of over 82%. The 3DEM-NPD method allowed us to establish a metric to quantify nanoparticle transport at the single nanoparticle level and to quantify the morphological features of ~2,800 vesicles. We find that on average there are only 2.4 nanoparticles per vesicle with a theoretical maximum of 158 nanoparticles per vesicle (~66x increase). These surprising results suggest the need to increase vesicle encapsulation efficiency for improved transport and they provide a benchmark for increasing nanoparticle transport and delivery. This technique may provide unique insights into the interactions between medical agents, drug carriers, emerging materials, and cells at the single-nanoparticle level throughout tissues.
The ternary complex of Mn
2+
, synthetic decapeptide DP1 (DEHGTAVMLK), and orthophosphate is a superb antioxidant
Authors: Yang Hao , Sharma Ajay , Daly Michael J. , Hoffman Brian M.
Published: December 2024

Mn
2+
coordinated by orthophosphate (Pi), metabolites, or peptides acts as a superoxide dismutase (SOD), and these Mn antioxidant complexes are universally accumulated in extremely radiation-resistant cell types across the tree of life. This behavior prompted design of decapeptide DP1 (DEHGTAVMLK) as a Mn
2+
ligand, and development of a highly potent Mn
2+
-antioxidant (MDP) containing [Pi] = 25 mM, and [DP1] = 3 mM, the ratio found in the radioresistant bacterium
Deinococcus radiodurans
, with [Mn
2+
] = 1 mM. MDP is an exceptional antioxidant, both in vitro and in vivo, and has reinvigorated the development of radiation-inactivated whole-cell vaccines. This study investigates the nature of the active Mn
2+
complex in MDP. We measure the affinity of DP1 for the substitutionally labile Mn
2+
ion using isothermal-titration calorimetry (ITC) and use changes in the Mn
2+
solution EPR spectrum to determine affinities of Mn
2+
for DP1 and for Pi, and to monitor Mn
2+
ligation while titrated with the fixed Pi/DP1 ratio of MDP, 25/3, using ENDOR/ESEEM to characterize DP1 ligation to Mn
2+
. In parallel,
1
H NMR of DP1 was used to monitor binding interactions between Pi and DP1, and DP1 binding to the diamagnetic Ca
2+
. We report: i) DP1 forms an extremely weak, dynamic Mn
2+
complex (K
a
≈ 40 M
−1
) ii) Mn
2+
binds Pi much more strongly (K
a
≈ 390 M
−1
) as shown previously, but iii) DP1 and Pi jointly bind to Mn
2+
in MDP to form a ternary Mn
2+
(Pi) (DP1) complex with greater formation-constant than Pi alone (K
a
app
≈ 670 M
−1
). It is this ternary complex that is the superb antioxidant in MDP.
Enhancing aluminium resistance in wheat (
Triticum aestivum
L.) by exploring for novel genes in the wheat genome
Authors: Emebiri Livinus , Raman Harsh
Published: December 2024

Aluminium (Al
3+
) toxicity is a major constraint to crop production worldwide and is considered second only to drought for its importance as an agronomic challenge. A common practice to manage the impact is the application of lime but this is expensive, and it can take years for the lime to be effective in ameliorating the subsoil acidity. Plant species with a natural ability to adapt to Al
3+
toxicity offer an option to maintain production while amelioration efforts continue, especially in low-rainfall areas where yield responses to lime is less profitable. In wheat (
Triticum aestivum
L.), the genes conferring Al
3+
resistance have been extensively researched over the years through classical inheritance, cytogenetic, quantitative trait locus (QTL) and genome-wide association studies, and transcriptional analyses. As a focal point for this discussion, we assembled a total of 212 QTL from research papers published between 2006 and 2024, and their physical positions were projected on the sequenced genome of the moderately Al
3+
-resistant hexaploid wheat variety, Chinese Spring. The markers were distributed across the 21 wheat chromosomes, with the highest numbers on chromosomes 3B, 4D and 7A and the lowest on chromosomes 3D and 5D. The physical mapping of significantly associated markers onto the reference genome map uncovered novel candidate genes. These include wheat aluminium-induced (Wali) genes, the ATP-binding cassette (ABC) transporters, phytosulfokine receptor (PSKR), PIN-formed (PIN, auxin transporter), NAC (NAC domain), WRKY (WRKY domain) and natural resistance-associated macrophage proteins (NRAMP). These were discussed to provide a contextual review of gaps that can be exploited in enhancing Al
3+
resistance in wheat, which can lead to the discovery of novel genes and the development of improved cultivars.
Axion-like universal gravitational wave interpretation of pulsar timing array data
Authors: Lozanov Kaloian D , Pi Shi , Sasaki Misao , Takhistov Volodymyr , Wang Ao
Published: December 2024

Formation of cosmological solitons is generically accompanied by production of gravitational waves (GWs), with a universal GW background expected at frequency scales below that of non-linear dynamics. Beginning with a general phenomenological description of GWs associated with soliton formation, we demonstrate that universal GW background from axion-like particle solitonic oscillons provides a viable interpretation to the recent NANOGrav 15 year pulsar timing array (PTA) data, which does not suffer from the overproduction of primordial black holes. We show that PTA data displays preference for models where formed solitons do not strongly interact or cluster. Coincidence observations with Nancy Roman telescope will allow to discriminate between distinct scenarios of cosmological solitons.
Textile actuators based on electrochemical lithiation of silicon thin films
Authors: Schmidl Gabriele , Jia Guobin , Konkin Gulnara , Brückner Uwe , Graf Leonie , Hupfer Maximilian L , Gawlik Annett , Richter Klaus , Plentz Jonathan
Published: December 2024

The aim of this study was to investigate whether a textile electrode coated with an amorphous silicon thin film can be used as an actuator element in a lithium electrolysis process in comparison to a crysralline silicon wafer stripe. It is well known from battery research that a deformation of the silicon electrode occurs during lithiation. This reversible process is being studied as a mechanical switch to move lightweight textiles for potential applications such as ventilation, thermal management, privacy protection, etc. To identify a solution, silicon thin film coatings on textile substrates, electrolytes and the lithiation process have been examined under both inert laboratory and application conditions. Methods such as cyclic voltammetry, amperometry and impedance spectroscopy were used to analyze the electrolytic process, and secondary ion mass spectrometry and electrical analysis were used to obtain material information. It is shown that the charging and discharging of lithium ions is associated with bending for more than 5 cycles. During this process, repeated forward and backward movements of the textile electrode were observed at low voltages below −10 V. Bending forces in the range of 0.2–0.7 mN dependent on the charging time, and a current flow in the range of −0.01 to −440 µA dependent on the voltage, were measured. This is suitable for the scenario where low force is required.
An impact localization method of composite fan blades based on stress wave features
Authors: Zhang Qingchen , Zhao Bowen , Liu Qijian , Liu Hailong , Huang Meiao , Qing Xinlin
Published: December 2024

Impact monitoring in real-time is an effective approach to ensure the integrity and safety of aircraft engine composite fan blades. The changing curvature of composite fan blades and the anisotropic nature of the material make it difficult to achieve accurate impact localization with the existing impact monitoring techniques. In this paper, an impact localization method based on stress wave features is proposed to accurately locate impact sources for composite fan blades. Firstly, a sensor array attached to the surface of the fan blade with variable curvatures is used to record the stress waves caused by the impact. Secondly, an adaptive signal decomposition method is used to decompose the original impact signals to obtain the components at different frequency regions. Thirdly, the features of component within the highest frequency region, having a monotonic attenuation relationship with distance and less influenced by material anisotropy, are extracted and fused. Finally, the improved weighted centroid localization algorithm using the fused feature is used to achieve accurate impact localization. Validation is also conducted on a custom-made experimental blade, achieving an average error of 7.9%. The monitoring results demonstrate that the developed method can achieve high-precision impact localization on composite fan blades and it has practical engineering value for monitoring in aerospace engines.
Resonance phenomenon for an underdamped bistable system with additive dichotomous noise and multiplicative noise
Authors: Cao Yudong , He Zhiguo , Fu Xuemin
Published: December 2024

Vibrational resonance (VR) and stochastic resonance for an underdamped bistable system driven by one high-frequency (HF) and one low-frequency (LF) periodic force with additive dichotomous noise, additive white noise and multiplicative white noise are investigated. The dynamical equation corresponding to the LF periodic force is obtained by decomposing the system output into one HF motion and one LF motion. Under the condition of weak LF signal, based on two-state theory, the system output signal-to-noise ratio (SNR) is derived. It is shown that the SNR can reach one peak value with the variation of the amplitude of the dichotomous noise. VR phenomenon can be observed when the SNR varies with both the amplitude and the frequency of the HF signal. One resonance peak occurs when the SNR changes with the strength of the multiplicative noise. The SNR can obtain one maximum value as increasing the system damping coefficient and increasing the intensity of the additive noise.
Design of Artificial Intelligence for Evaluation of In Vitro Potato (Solanum tuberosum) Microtuber Growth from Tissue Culture Based on Digital Imagery
Authors: Diningrat Diky Setya , Febriyossa Adelia , Suryanto Eka Dodi , Maulana Bagoes , Sari Ayu Nirmala , Asmin  , Nainggolan Tiara Bunga , Hasibuan Ali Ahmatul Umri , Rambe Khadra Ulfah
Published: December 2024

The goal of this research is to introduce an AI model for assessing the development and yield of in vitro potato microtubers using tissue culture technology. The AI system was created to assist lab personnel in making decisions regarding microtubers produced through tissue culture. Previous research has indicated that the growth of microtubers is significantly impacted by the intensity of light. Once microtubers have formed, the light intensity needs to be decreased until it becomes dark, to facilitate optimal microtuber growth. The AI system takes in a digital image of the plant and other relevant information provided by the laboratory assistant. The digital image is then automatically processed to extract specific color intensity data for the microtubers and leaves. This intensity data is used as input for the fuzzy interference engine, which combines it with existing rules in the database to generate new rules. Additionally, the AI system employs a forward chaining mechanism to provide recommendations for appropriate actions that laboratory assistants should take based on the condition of a particular microtuber. Trial results demonstrate that the system’s recommendations are quite satisfactory, with an average accuracy of 95% in handling recommendations for potato microtubers.
The Solid-state Synthesis of MnFe2O4 and its Application as Photo-Fenton Catalyst for the Degradation of dye
Authors: Awaluddin A , Nanda R , Ilahi A N , Amiruddin E , Deraf I F P , Siregar S S
Published: December 2024

Manganese ferrite spinel has been successfully synthesized using birnessite-type manganese oxide (MnO2) and ferric chloride (FeCl3) through solid-state method. The solid product was then calcined at different temperatures to study the effect of the calcination on the structure and catalytic activity. The as-synthesized ferrite was further characterized by XRD, FTIR and Raman spectroscopy, and UV-DRS spectroscopy. The XRD results revealed that the predominant phase present is MnFe2O4, with the cyptomelane-type MnO2 appearing as a minor components. The increase in the calcination temperature resulted in more crystalline phase and purity of MnFe2O4. The IR vibration modes are found in-between 432-745 cm−1 with Fe-O bond at 680 cm−1 and 745 cm−1, and Mn-O at 412 cm−1, 432 cm−1 and 488 cm−1 indicated the spinel phase of the MnFe2O4. The Raman results further confirmed the presence of the MnFe2O4 phase. The UV-DRS results indicated that the calcination temperature has a strong influence on the optical properties. The catalytic test was conducted for the degradation of methylene blue (MB) dye using the photo-Fenton method and the MnFe2O4 calcined at 700°C showed the highest catalytic activity. In the optimum condition, the MnFe2O4 was able to degrade 97.99% of MB with the following conditions: 0.04 g of MnFe2O4, 5 mL of H2O2, and 50 ppm of initial MB concentration. The optimum condition seems to correlate with a low band gap and high purity of the MnFe2O4 phase.