Viscoelastic behavior of highly elastic magnetic elastomers has been studied by three different experimental techniques: elongation, static and dynamic shears. It has been shown that the elastic ...modulus of the materials increases considerably in an external homogeneous magnetic field of up to 0.3
T (100-fold increase of the tangential modulus has been observed at small 1–4% deformations). The appearance of the new effect of pseudo-plasticity induced by the magnetic field has been observed leading to a considerable (up to 100-fold) increase in the shear loss modulus of the composites.
The delayed-detonation explosion mechanism applied to a Chandrasekhar-mass white dwarf offers a very attractive model to explain the inferred characteristics of Type Ia supernovae (SNe Ia). The ...resulting ejecta are chemically stratified, have the same mass and roughly the same asymptotic kinetic energy, but exhibit a range in 56Ni mass. We investigate the contemporaneous photometric and spectroscopic properties of a sequence of delayed-detonation models, characterized by 56Ni masses between 0.18 and 0.81 M. Starting at 1 d after explosion, we perform the full non-local thermodynamic equilibrium, time-dependent radiative transfer with the code cmfgen, with an accurate treatment of line blanketing, and compare our results to SNe Ia at bolometric maximum. Despite the 1D treatment, our approach delivers an excellent agreement to observations. We recover the range of SN Ia luminosities, colours and spectral characteristics from the near-ultraviolet to 1 μm, for standard as well as low-luminosity 91bg-like SNe Ia. Our models predict an increase in rise time to peak with increasing 56Ni mass, from ∼15 to ∼21 d, yield peak bolometric luminosities that match Arnett's rule to within 10 per cent and reproduce the much smaller scatter in near-infrared magnitudes compared to the optical. We reproduce the morphology of individual spectral features, the stiff dependence of the
spectroscopic ratio on 56Ni mass and the onset of blanketing from Ti ii/Sc ii in low-luminosity SNe Ia with a 56Ni mass 0.3 M. We find that ionization effects, which often dominate over abundance variations, can produce high-velocity features in Ca ii lines, even in 1D. Distinguishing between different SN Ia explosion mechanisms is a considerable challenge but the results presented here provide additional support to the viability of the delayed-detonation model.
ABSTRACT
This paper introduces a novel method of modelling acoustic and elastic wave propagation in inhomogeneous media with sharp variations of physical properties based on the recently developed ...grid‐characteristic method which considers different types of waves generated in inhomogeneous linear‐elastic media (e.g., longitudinal, transverse, Stoneley, Rayleigh, scattered PP‐, SS‐waves, and converted PS‐ and SP‐waves). In the framework of this method, the problem of solving acoustic or elastic wave equations is reduced to the interpolation of the solutions, determined at earlier time, thus avoiding a direct solution of the large systems of linear equations required by the FD or FE methods. We apply the grid‐characteristic method to compare wave phenomena computed using the acoustic and elastic wave equations in geological medium containing a hydrocarbon reservoir or a fracture zone. The results of this study demonstrate that the developed algorithm can be used as an effective technique for modelling wave phenomena in the models containing hydrocarbon reservoir and/or the fracture zones, which are important targets of seismic exploration.
Abstract
We report the results of spectroscopic and photometric observations of the emission-line object IRAS 07080+0605 carried out in 2004–2021. We found that the object is significantly ...underluminous for its spectroscopic properties (
T
eff
= 8500 ± 500 K,
log
g
= 2.0 ± 0.5), if a strong visual attenuation by a factor of ∼43 found through the spectral energy distribution modeling is not taken into account. Visual brightness variations with a stable period of 190 days but a variable amplitude of ∼0.2 mag were found in the ASAS SN data and attributed to variable circumstellar extinction in the dusty disk. We also found that the observed behavior of IRAS 07080+0605 is similar to that of the protoplanetary nebula Red Rectangle. The dusty disk of IRAS 07080+0605 shows the presence of carbonaceous particles (∼10%–20% of the total dust content) and polycyclic aromatic hydrocarbon emission bands. However, IRAS 07080+0605 shows no obvious signs of the refractory element depletion, which is common in post–asymptotic giant branch (AGB) dusty binaries, or of a visual nebula. Absorption-line positions vary with an amplitude of ∼25 km s
−1
, suggesting the presence of a secondary component. Spectroscopic monitoring on a timescale from days to months is needed to search for regular variations. We conclude that IRAS 07080+0605 is most likely a binary system with an A-type component on its way toward the post-AGB evolutionary stage, as binarity is capable of explaining most of the observed features.
•FTIR spectra of Methylene Blue cation (MB+) were analyzed in their free form (gas-phase), hydrated crystal form and in solution.•The complications, emerging during the interpretation are due to the ...high activity of this molecule to the intermolecular interactions.•FTIR spectra of aqueous solution and hydrate show manifestation of dimerization and H-aggregation.•Intermolecular hydrogen bonds and π–π interaction of MB+ aromatic rings were observed during self-association.•The analysis of FTIR spectra indicates the identical nature of emerging intermolecular interactions for H-aggregates and hydrates.
Fourier-transform infrared (FTIR) spectra of cationic dye methylene blue (MB) were analyzed in its free form (gas-phase), hydrated crystalline state, and dried MB solution. A good agreement of experimental FTIR spectra with the results of theoretical calculations of MB vibration modes was observed. The calculations were performed by means of the density functional theory (DFT/B3LYP/6–31+G(d)), using Gaussian-03 software package. Vibrational bands of the N+(CH3)2 (1640–1650cm−1) and C-S-C (625-615, 1095cm−1) functional groups are characteristic of the presence of MB monomers in the studied samples. The participation of the N+(CH3)2 functional group in the formation of one bridging H-bond with OH groups of the solvent has been confirmed. The decrease in intensity of these bands with the increase of the fraction of dimers and H-aggregates of MB was observed. It was concluded that the configuration and primary localization of the charge in the heterocycle of ionic form MB+ are changed in the case of formation of dimers and H-aggregates. For samples with a dominant fraction of dimers and H-aggregates, the occurrence of intermolecular H-bonds of the type Nhet…Н-O⋯S+het was found. The occurrence of peaks at 1339–1356, 1481–1491, and 885cm−1 was observed. It was concluded that there is formation of dimers and H-aggregates due to interaction of sulfur and nitrogen atoms with OH groups of water molecules. Moreover, the manifestation of π-π stacking interactions of aromatic rings of the heterocycle of ionic form MB+ during self-association was determined on the basis of data on the behavior of the peaks of heterocyclic of СН (3050–3015cm−1), СС, СN (1600–1595cm−1), СС, and СN (1564–1546cm−1) vibrations.
We theoretically investigate quasiparticle interference in superconducting topological insulators with the nematic order parameter. This order parameter spontaneously breaks the rotational symmetry ...of the crystal. Such violation of rotational symmetry is seen in both coordinate and momentum spaces of the quasiparticles interference patterns. For small bias voltages quasiparticle interference incommensurate with the crystal symmetry and shows nematic behavior. If the bias voltage is comparable with the value of the order parameter interference picture is similar to the interference picture of the normal state. Interference patterns are sensitive to the orientation of the nematicity. We compare our results with the existing experimental data.
•Scattering on the charged impurity in topological superconductor with Eu pairing is studied.•At low bias QPI patterns reproduce twofold symmetry of the nematic order parameter.•Different orientations of the order parameter may be identified via QPI reflexes.•Calculated shortwave reflexes are in well agreement with the experimental one, while longwave reflexes are not.
Abstract HD 327083 is a binary system that consists of two supergiant components and exhibits the Be phenomenon. In this paper, we report the determination of a new set of the system’s fundamental ...parameters using a combination of photometric and spectroscopic data as well as the Gaia EDR3 distance. We found that the orbital period of the system is 107.68 ± 0.02 days. The spectral line content implies the effective temperatures of ≈7000 K and 25,400 ± 1400 K, while the photometric variations are consistent with the radii of ≈106 R ⊙ and ≈10 R ⊙ for the cool and hot components, respectively. The absorption lines of the cool component show a radial velocity semiamplitude of 48.3 ± 1.7 km s −1 , similar to that of the emission lines that originate around the hot component. The inclination of the system to the line of sight is 47 − 20 + 17 °. Modeling of the system's evolutionary history suggests that the components have masses of ∼12.5 M ⊙ and currently undergo mass transfer between them. This configuration, which takes in heating of the surface of the cool component by the radiation from the hot one, can reproduce the photometric and spectroscopic data and is in agreement with previous infrared observations of the circumbinary disk. The results of this study further confirm the hypothesis that the reason for the presence of the Be phenomenon in most objects is a consequence of the evolution of various binary systems.
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