We review studies of vortical motion and the resulting global polarization of
and
hyperons in heavy-ion collisions, in particular, within 3FD model. 3FD predictions for the global midrapidity ...polarization in the FAIR-NICA energy range are presented. The 3FD simulations indicate that energy dependence of the observed global polarization of hyperons in the midrapidity region is a consequence of the decrease of the vorticity in the central region with the collision energy rise because of pushing out the vorticity field into the fragmentation regions. At high collision energies this pushing-out results in a peculiar vortical structure consisting of two vortex rings: one ring in the target fragmentation region and another one in the projectile fragmentation region with matter rotation being opposite in these two rings.
Magnetodielectric materials are characterized by a strong coupling of the magnetic and dielectric properties and, in rare cases, simultaneously show both magnetic and polar order. Among other ...multiferroics, TbMnO3 and GdMnO3 reveal a strong magneto-dielectric coupling and as a consequence fundamentally different spin excitations exist: electro-active magnons (or electromagnons), spin waves that can be excited by a.c. electric fields. Here we provide evidence that these excitations appear in the phase with an incommensurate magnetic structure of the manganese spins. In external magnetic fields this incommensurate structure can be suppressed and the electromagnons wiped out, thereby inducing considerable changes in the index of refraction from d.c. up to terahertz frequencies. Hence, besides adding a creature to the zoo of fundamental excitations, the refractive index can be tuned by moderate magnetic fields, which enables the design of the next generation of optical switches and optoelectronic devices.
The Budker Institute of Nuclear Physics in worldwide collaboration has developed a project of a 14 MeV neutron source for fusion material studies and other applications. The projected neutron source ...of the plasma type is based on the gas dynamic trap (GDT), which is a special magnetic mirror system for plasma confinement. Essential progress in plasma parameters has been achieved in recent experiments at the GDT facility in the Budker Institute, which is a hydrogen (deuterium) prototype of the source. Stable confinement of hot-ion plasmas with the relative pressure exceeding 0.5 was demonstrated. The electron temperature was increased up to 0.9 keV in the regime with additional electron cyclotron resonance heating (ECRH) of a moderate power. These parameters are the record for axisymmetric open mirror traps. These achievements elevate the projects of a GDT-based neutron source on a higher level of competitive ability and make it possible to construct a source with parameters suitable for materials testing today. The paper presents the progress in experimental studies and numerical simulations of the mirror-based fusion neutron source and its possible applications including a fusion material test facility and a fusion-fission hybrid system.
Metastable alloys based on the Ti–Nb system are considered promising candidates to replace the biomaterials currently used in medicine. Several very promising alloys like TNTM, TNZT, etc., were ...recently developed by adding Zr, Ta, Mo, Fe, or other elements to the Ti–Nb system. However, only a few fundamental studies were devoted to the structural characterisation of Ti–Nb alloys in the as-cast state. In this study, we analyze the microstructure, the phase transformations, the lattice parameters, the interaction of different phases, and Young's modulus of a wide range of Ti–Nb alloys produced by suction casting. The structure of experimental samples was investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and synchrotron X-ray diffraction (SXRD) analysis. The samples with a Nb content of less than 17.5 wt % consisted of α′ phase. The pure α’’ phase was observed only in the alloy with 17.5 wt % Nb. The alloys with an intermediate content of Nb (20–30 wt %) contained a mixture of α’’, β and ω phases. The samples with 30–35 wt % Nb consisted of a mix of β and ω phases. The samples with 37.5 and 45 wt % Nb included two types of β phase. In addition to the regular β phase, a little detectable amount of bcc phase was observed with a larger lattice parameter named βminor. The mechanical properties strongly depended on the phase composition. We found that for α’’-dominated alloys, there is a correlation between Young's modulus and orthorhombicity and c/a ratio of α’’ phase. The lowest Young's modulus (47 GPa) was observed in the alloy with 17.5 wt % Nb, which has orthorhombicity close to unity and c/a ratio close to 1.58.
•High orthorhombicity and low c/a ratio of α’’ phase result in low Young's modulus.•Small volume change in β→ω transformation causes a high Young's modulus.•Two different β metastable phases have been observed in Nb rich alloys.•Lattice strains in β→ω transformations are smaller than in β→α′/α″ transformations.
We report the synthesis and systematic investigation of nine different indigo derivatives as promising materials for sustainable organic electronics. It has been shown that chemical design allows one ...to tune optoelectronic properties of indigoids as well as their semiconductor performance in OFETs. Fundamental correlations between the molecular structures of indigo derivatives, structural characteristics of their films, charge carrier transport properties and transistor characteristics have been revealed. Particularly important was lowering the LUMO energy levels of indigoids bearing strong electron withdrawing groups which improved dramatically ambient stability of n-type OFETs. Chemical structures of novel indigoids enabling truly air-stable n-channel OFET operation were proposed.
ABSTRACT The "VISTA near-infrared YJKs survey of the Magellanic Clouds System" (VMC) is collecting deep Ks-band time-series photometry of pulsating variable stars hosted by the two Magellanic Clouds ...and their connecting Bridge. In this paper, we present Y, J, Ks light curves for a sample of 4172 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with literature V values, allowed us to construct a variety of period-luminosity (PL), period-luminosity-color (PLC), and period-Wesenheit (PW) relationships, which are valid for Fundamental (F), First Overtone (FO), and Second Overtone (SO) pulsators. The relations involving the V, J, Ks bands are in agreement with their counterparts in the literature. As for the Y band, to our knowledge, we present the first CC PL, PW, and PLC relations ever derived using this filter. We also present the first near-infrared PL, PW, and PLC relations for SO pulsators to date. We used PW(V, Ks) to estimate the relative SMC-LMC distance and, in turn, the absolute distance to the SMC. For the former quantity, we find a value of Δμ = 0.55 ± 0.04 mag, which is in rather good agreement with other evaluations based on CCs, but significantly larger than the results obtained from older population II distance indicators. This discrepancy might be due to the different geometric distributions of young and old tracers in both Clouds. As for the absolute distance to the SMC, our best estimates are μSMC = 19.01 ± 0.05 mag and μSMC = 19.04 ± 0.06 mag, based on two distance measurements to the LMC which rely on accurate CC and eclipsing Cepheid binary data, respectively.
The Khasurty Fossil Insect Lagerstätte Kopylov, D. S.; Rasnitsyn, A. P.; Aristov, D. S. ...
Paleontological journal,
12/2020, Letnik:
54, Številka:
11
Journal Article
Recenzirano
The Khasurty locality (Lower Cretaceous of Transbaikalia, Russia) is one of the largest fossil insect sites in the region. Over the entire period of study, more than 6000 insect imprints have been ...collected here, representing 16 orders and 130 families. Dipterans, aphids and hymenopterans are the most common forms here, the most diverse taxa are Diptera, Hymenoptera, Coleoptera and Trichoptera. In addition to insects, remains of crustaceans, mosses, liverworts and vascular plants were found in Khasurty, as well as occasional finds of arachnids, bird feathers and fish scales. Two new families, 17 new genera and 21 new species of Trichoptera, two new species of Orthoptera, one new genus and species of Phasmatoptera, one new species of Reculida, three new genera and species of Hemiptera, a new genus and species of Thysanoptera, a new genus and species of Hymenoptera, a new subfamily, two new genera and six new species of Lepidoptera, three new genera and four new species of Neuroptera, as well as a new genus and species of liverworts are described. In terms of the composition of the fauna and flora, the Khasurty locality is very peculiar, it includes both Jurassic and Cretaceous taxa, but in general it can be attributed to the Jehol biota.
Abstract
Recent surveys have uncovered new young massive clusters that host dozens of red supergiants (RSGs) near the inner Galaxy. However, many of them have still not been fully studied. Using Very ...Large Telescope/X-shooter near-infrared spectra, we present the first radial velocity analysis for the putative members of the candidate RSG cluster Alicante-8. Our results show a large dispersion of radial velocities among the candidate member stars, indicating that Alicante-8 does not seem to be a real cluster, unlike Alicante-7 and Alicante-10, which are confirmed by the distribution of the radial velocities of their RSG members. Measuring the spectral indices reveals that the assumption that the candidate stars are RSGs was incorrect, leading to the misclassification of Alicante-8 as a candidate RSG cluster. Our results imply that spectral classification based on the widely used CO band at 2.3
μ
m alone is not a sufficient criterion, because both red giants and RSGs can attain similar CO equivalent widths, and that spectroscopic radial velocities are needed in order to confirm unambiguously the cluster membership.
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