Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

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SIMULATION OF ACOUSTIC ENERGY TRANSFER THROUGH A MULTILAYER SYSTEM FOR CHANGING THE RHEOLOGICAL PROPERTIES OF HYDROCARBONS

Relevance of the research is caused by the need to determine the acoustic energy level of ultrasonic exposure propagation in a multilayer system. This is required to develop the engineering project of ultrasonic devices which would modify the hydrocarbon fuel rheological properties. This, in its turn, could further their application in energy complex facilities in the Arctic and Antarctic environments. Aim: to develop a mathematical model for ultrasonic radiation propagation in a multilayer system with the determination of the energy at each resonance. Such a model would take into account the design-type of the ultrasound resonant emitter. Object: design-type of the ultrasound resonant emitter, multilayer system and physical model system: «ultrasonic emitter – multilayer system». Methods: mathematical modeling of ultrasonic radiation propagation within a multilayer system, considering the following impact factors: design-type of the ultrasound resonant emitter, operating mode, number of layers and material mechanical properties of the multilayer system. Experiments were based on the physical model system: «ultrasonic emitter – multilayer system». Experimental data verification proved the effectiveness of the mathematical model. Results. This mathematical model enables to determine and calculate the energy and frequency characteristics of acoustic radiation in each layer within the multilayer system itself. Ultrasonic resonant emitter operating experiments under one plexiglass-layer, two plexiglass-layer and three-plexiglass layer loads have been carried out. Estimated data are in good agreement with experiments, whereas, discrepancy does not exceed 15 %. Conclusion. Proposed and developed mathematical model enables the ultrasound resonant emitter-type to be designed, according to required power source capacity and frequency range. In this case, it could be applied for hydrocarbon fuel laboratory research

Effect of Diamond Phase Dispersion on the Properties of Diamond-SiC-Si Composites

The research aimed at the composition optimization for diamond-SiC-Si composites. The effect of a porous diamond workpiece was studied on the properties (porosity, density, modulus of elasticity, phase composition) of the product of its siliconization with molten silicon. The lowest porosity and highest modulus of elasticity were observed in the case of using mixed matrices with the maximum size of diamond grains of 250/200 μm for siliconization. The best results in terms of the sound speed (16,600 m/s) and elasticity modulus (860 GPa) were achieved by microwave processing of a composite containing detonation nanodiamonds

The Influence of Zn3(PO4)2:Mn–Luminophores Synthesis Conditions on their Surface and Luminescent Features

A technology, that allows production effective x-ray luminescent phosphors Zn3(PO4)2:Mn2+ with nanosized particles from the water solution by sol-gel method, and directional regulated their luminescence color from green to red was developed. X-ray intensity and spectra, phase structure, and surface properties of synthesized samples depending on the synthesis conditions was studied. The conditions of synthesis which allow to obtain the samples according to the demands for the luminophores of medical assignment were determined.</jats:p

Luminescent materials on the basis of yttrium oxide and yttrium aluminum garnet used for photodynamic therapy

Finely-dispersed phosphors of Y2O3:Eu and Y3Al5O12:Eu have been synthesized with the help of Pechini method and the method of self-propagating high-temperature synthesis (SHS). During the synthesis of phosphors on the basis of Y2O3 carried out with Pechini method the size of crystallites increases with the enlargement of concentration of yttrium, but it decreases when the method of SHS is applied. The structure of phosphors on the basis of Y3Al5O12 (YAG) is strongly amorphized. This fact agrees with the data of XRD and with the prevalence of the band with λmax = 613 nm in the spectra of this phosphor. The enlargement of yttrium concentration in it promotes the amorphisation of yttrium aluminum garnet and the decrease of a crystal phase content. The sample of Y3Al5O12:Eu synthesized with Pechini method has the maximum intensity, while in conditions of excitement with “high-level” X-ray radiation which corresponds to the radiation of industrial medical X-ray apparatus, the phosphor of Y2O3:Eu synthesized with the help of SHS showed the largest intensity. Colloid solutions prepared with the use of the samples synthesized by SHS method revealed a higher steadiness and a lower disposition to the sedimentation process. The samples of Y2O3:Eu phosphor possessing the smallest size of particles and the highest intensity of X-ray luminescence are the most suitable for the creation of pharmacological drugs used for photodynamic therapy

Luminescent materials on the basis of yttrium oxide and yttrium aluminum garnet used for photodynamic therapy

Finely-dispersed phosphors of Y2O3:Eu and Y3Al5O12:Eu have been synthesized with the help of Pechini method and the method of self-propagating high-temperature synthesis (SHS). During the synthesis of phosphors on the basis of Y2O3 carried out with Pechini method the size of crystallites increases with the enlargement of concentration of yttrium, but it decreases when the method of SHS is applied. The structure of phosphors on the basis of Y3Al5O12 (YAG) is strongly amorphized. This fact agrees with the data of XRD and with the prevalence of the band with λmax = 613 nm in the spectra of this phosphor. The enlargement of yttrium concentration in it promotes the amorphisation of yttrium aluminum garnet and the decrease of a crystal phase content. The sample of Y3Al5O12:Eu synthesized with Pechini method has the maximum intensity, while in conditions of excitement with “high-level” X-ray radiation which corresponds to the radiation of industrial medical X-ray apparatus, the phosphor of Y2O3:Eu synthesized with the help of SHS showed the largest intensity. Colloid solutions prepared with the use of the samples synthesized by SHS method revealed a higher steadiness and a lower disposition to the sedimentation process. The samples of Y2O3:Eu phosphor possessing the smallest size of particles and the highest intensity of X-ray luminescence are the most suitable for the creation of pharmacological drugs used for photodynamic therapy

Hydrophobic-core PEGylated graft copolymer-stabilized nanoparticles composed of insoluble non-nucleoside reverse transcriptase inhibitors exhibit strong anti-HIV activity

Benzophenone-uracil (BPU) scaffold-derived candidate compounds are efficient non-nucleoside reverse transcriptase inhibitors (NNRTI) with extremely low solubility in water. We proposed to use hydrophobic core (methoxypolyethylene glycol-polylysine) graft copolymer (HC-PGC) technology for stabilizing nanoparticle-based formulations of BPU NNRTI in water. Co-lyophilization of NNRTI/HC-PGC mixtures resulted in dry powders that could be easily reconstituted with the formation of 150-250 nm stable nanoparticles (NP). The NP and HC-PGC were non-toxic in experiments with TZM-bl reporter cells. Nanoparticles containing selected efficient candidate Z107 NNRTI preserved the ability to inhibit HIV-1 reverse transcriptase polymerase activities with no appreciable change of EC50. The formulation with HC-PGC bearing residues of oleic acid resulted in nanoparticles that were nearly identical in anti-HIV-1 potency when compared to Z107 solutions in DMSO (EC50=7.5+/-3.8 vs. 8.2+/-5.1 nM). Therefore, hydrophobic core macromolecular stabilizers form nanoparticles with insoluble NNRTI while preserving the antiviral activity of the drug cargo

Single-Mode Lasing from Imprinted Halide-Perovskite Microdisks

Halide-perovskite microlasers have demonstrated fascinating performance owing to their low-threshold lasing at room temperature and low-cost fabrication. However, being synthesized chemically, controllable fabrication of such microlasers remains challenging, and it requires template-assisted growth or complicated nanolithography. Here, we suggest and implement an approach for the fabrication of microlasers by direct laser ablation of a thin film on glass with donut-shaped femtosecond laser beams. The fabricated microlasers represent MAPbBrxIy microdisks with 760 nm thickness and diameters ranging from 2 to 9 μm that are controlled by a topological charge of the vortex beam. As a result, this method allows one to fabricate single-mode perovskite microlasers operating at room temperature in a broad spectral range (550–800 nm) with Q-factors up to 5500. High-speed fabrication and reproducibility of microdisk parameters, as well as a precise control of their location on a surface, make it possible to fabricate centimeter-sized arrays of such microlasers. Our finding is important for direct writing of fully integrated coherent light sources for advanced photonic and optoelectronic circuitry.This work was supported by the Ministry of Education and Science of the Russian Federation (Grant No. 14.Y26.31.0010, numerical simulations and optical measurements), Russian Science Foundation (Grant No. 17-19-01325, fs laser fabrication), Priority research project “Materials” of the Far Eastern Federal University, and also the Strategic Fund of the Australian National University