•As-cast and annealed high entropy alloys FeCrCoNiMnxVy (x, y=0, 1) were studied.•V turned CoCrFeNiMnx single FCC phase structure to σ phase matrix with FCC particles.•No effect of annealing on the ...phase composition of the alloys was observed.•Formation of σ phase resulted in considerable strengthening and loss in ductility.
Microstructure and mechanical properties of equimolar composition alloys FeCrCoNi, FeCrCoNiV, FeCrCoNiMn and FeCrCoNiMnV were studied in as-solidified and annealed conditions. The FeCrCoNi and FeCrCoNiMn alloys were single-phase FCC solid-solutions in both conditions. However, the FeCrCoNiV and FeCrCoNiMnV alloys consisted of the intermetallic σ-phase matrix with a tetragonal crystal lattice and precipitates of a disordered FCC phase. The crystal structures of these alloys were found to be not affected by annealing. A number of criteria were considered to explain phase composition of the studied alloys. It was shown that poor compatibility of V with other alloying elements caused significant distortions of FCC solid solution and thus promoted formation of the σ phase. Tensile and compressive properties of these alloys together with their microhardness were determined. Significant strengthening accompanied by the loss of ductility due to formation of the σ phase was demonstrated in the V containing alloys. The characteristics of the microstructure formation in the studied alloys were discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Ni
Mn
In
(close to 2-1-1 system) Heusler alloy was studied by magnetization measurement dependence on the temperature in magnetic fields of up to 13.5 T. The magnetocaloric effect measured by the ...direct method in quasi-adiabatic conditions showed a maximum value of ∆T
= -4.2 K at a temperature T = 212 K in a magnetic field of 10 T in the region of martensitic transformation. The structure of the alloy was studied by transmission electron microscopy (TEM) as a function of the temperature and the thickness of the sample foil. In the temperature range from 353 to 215 K, at least two processes were established. The results of the study indicate that the concentration stratification occurs according to the mechanism of spinodal decomposition (conditionally spinodal decomposition) into nanoscale regions. At a temperature of 215 K and lower, martensitic phase with 14 M modulation is observed in the alloy at thicknesses greater than 50 nm. Some austenite is also observed. In foils with thickness of less than 50 nm in a temperature range from 353 to 100 Km only the initial austenite, which has not transformed, was found.
We have developed a deep generative model, generative tensorial reinforcement learning (GENTRL), for de novo small-molecule design. GENTRL optimizes synthetic feasibility, novelty, and biological ...activity. We used GENTRL to discover potent inhibitors of discoidin domain receptor 1 (DDR1), a kinase target implicated in fibrosis and other diseases, in 21 days. Four compounds were active in biochemical assays, and two were validated in cell-based assays. One lead candidate was tested and demonstrated favorable pharmacokinetics in mice.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Data on the electrolytic preparation of β -Ta in halide and oxohalide melts were reported. It was shown that during electrolysis in halide melts containing K 2 TaF 7 , the amount β -Ta in the ...cathodic products can be markedly increased by using a copper cathode with a definite texture. It was found that in chloride-oxofluoride melts the β -Ta content increases monotonically on passing from NaCl to KCl and RbCl melt. The dependencies of the β -Ta content in cathodic products on the ratio of oxygen to tantalum concentrations were studied in chloride-oxofluoride and fluoride-oxofluoride melts. The maxima of these dependences were identified and explained. It was shown that β -Ta could be obtained by electrolysis in molten salts only at temperatures below 850 °C.
Abstract The harmonic modulation of coherent systems gives rise to a wealth of physical phenomena, e.g., the AC-Stark effect and Mollow triplets, with important implications for coherent control and ...frequency conversion. Here, we demonstrate a novel regime of temporal coherence in oscillators harmonically driven at extreme energy modulation amplitudes relative to the modulation quantum. The studies were carried out by modulating a confined exciton-polariton Bose-Einstein condensate (BEC) by an acoustic wave. Features of the new regime are the appearance, in the spectral domain, of a comb of resonances termed acceleration beats with energy spacing tunable by the modulation amplitude and, in the time domain, of temporal correlations at time scales much shorter than the acoustic period, which also depend on the modulation amplitude. These features are quantitatively accounted for by a theoretical framework, which associates the beats with accelerated energy-change rates during the harmonic cycle. These observations are underpinned by the high sensitivity of the BEC energy to the acoustic driving, which simultaneously preserves the BEC’s temporal coherence. The acceleration beats are a general feature associated with accelerated energy changes: analogous features are thus also expected to appear under highly accelerated motion e.g., in connection with Cherenkov and Hawking radiation.
An ever growing demand for efficient energy conversion, for instance in luminescent lamps, flexible screens and solar cells, results in the current significant growth of research on functionalized ...nanomaterials for these applications. This paper reviews recent developments of a new class of optically active nanostructured materials based on
glasses doped with luminescent Ag nanoclusters
consisting of only a few Ag atoms, suitable for mercury-free white light generation and solar down-shifting. This new approach, based solely on Ag nanocluster doped glasses, is compared to other alternatives in the field of Ag and rare-earth ion co-doped materials.
We review recent progress in the field of luminescent Ag nanoclusters for the efficient photonic conversion, including white light generation.
► Radiation-protective composites were fabricated by solid state intermixing and thermal pressing. ► The composites based on UHMWPE contain В4С and W nanopowders as fillers. ► The mechanical and ...γ-radiation protective properties of the polymer-matrix nanocomposites were determined experimentally. ► For composites containing 12% B4C and 12% W the mechanical properties were studied prior to and after the irradiation with fast neutrons.
UHMWPE-based nanostructured composites containing B4C and W nanopowders were fabricated and studied. The mechanical and γ-radiation protective properties of the polymer-matrix nanocomposites were determined experimentally. For selected composites the mechanical properties were studied prior to and after the irradiation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
8.
Polariton-driven phonon laser Chafatinos, D. L.; Kuznetsov, A. S.; Anguiano, S. ...
Nature communications,
09/2020, Volume:
11, Issue:
1
Journal Article
Peer reviewed
Open access
Abstract
Efficient generation of phonons is an important ingredient for a prospective electrically-driven phonon laser. Hybrid quantum systems combining cavity quantum electrodynamics and ...optomechanics constitute a novel platform with potential for operation at the extremely high frequency range (30–300 GHz). We report on laser-like phonon emission in a hybrid system that optomechanically couples polariton Bose-Einstein condensates (BECs) with phonons in a semiconductor microcavity. The studied system comprises GaAs/AlAs quantum wells coupled to cavity-confined optical and vibrational modes. The non-resonant continuous wave laser excitation of a polariton BEC in an individual trap of a trap array, induces coherent mechanical self-oscillation, leading to the formation of spectral sidebands displaced by harmonics of the fundamental 20 GHz mode vibration frequency. This phonon “lasing” enhances the phonon occupation five orders of magnitude above the thermal value when tunable neighbor traps are red-shifted with respect to the pumped trap BEC emission at even harmonics of the vibration mode. These experiments, supported by a theoretical model, constitute the first demonstration of coherent cavity optomechanical phenomena with exciton polaritons, paving the way for new hybrid designs for quantum technologies, phonon lasers, and phonon-photon bidirectional translators.
Investigation of hafnium cathodic and anodic processes in chloride melts containing HfCl
4
revealed that two-hafnium electroreduction processes are corresponded two electrooxidation processes. The ...only difference between these processes was the presence of salt passivation under certain dissolution conditions. In chloride-fluoride melts containing K
2
HfF
6
the number of cathodic and anodic processes can be different due to the amount of hafnium ions passing into the melt during anodic dissolution exceeding the amount of fluorine anions necessary to bind them into fluoride complexes. Based on the experimental data it was found that the conclusion about the mirror reflection of cathodic and anodic processes is invalid in the case of a heteroligand composition of melts. It was determined that the dissolution in the NaCl-KCl-K
2
HfF
6
(10 wt%) melt at the anodic current density of >0.02 А∙cm
−2
was accompanied by the formation of Hf(IV) fluoride complexes and Hf(II) chloride complexes. It was shown that the appearance of hafnium complexes with different valence during anodic process in the NaCl-KCl-K
2
HfF
6
(10 wt%) melt is a highly undesirable phenomenon, which leads to the formation of metallic film on the surface of the melt decreasing the current efficiency for coating deposition.
Anodic processes were studied in chloride-fluoride, fluoride melts by voltammetry and gas chromatography mass spectrometry method. It was found that the reason for the occurrence of the anodic effect ...during the electrolysis of the KCl-KF-K
2
NbF
7
melt is the formation of the compound C
x
F
y
on the electrode surface, which has electrical insulating properties. Influence of oxide ions on the anodic processes in the KCl-KF-K
2
NbF
7
melt was investigated. It was determined that oxide ions and oxofluoride complexes of niobium oxidize at a glassy carbon electrode at more negative potentials than fluoride ions. The anodic effect in the chloride-fluoride melt containing oxide ions and oxofluoride complexes of niobium can be reached if the anodic current density will be higher than the limiting current density of electrooxidation of oxide ions and niobium oxofluoride complexes.
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