13 research outputs found
Development of multicomponent hybrid powders based on titanium and niobium carbides as a promising material for laser cladding
Multicomponent hybrid TiC-NbC(Zr, Si) powder was developed and manufactured by mechanosynthesis in a high-energy vibratory ball mill. High-purity fragmented TiC, NbC, Zr and Si powders were selected and mixed in a ratio of 60:15:10:15 at.%, respectively, to manufacture the above powder. Several modes of mechanosynthesis were chosen for the experiment: 3, 6, 9 and 12 hours. Scanning electron microscopy (SEM) and X-Ray diffraction (XRD) analyzes were used to study the morphology, chemical and phase compositions of the obtained TiC-NbC(Zr, Si) powder. The SEM analysis confirmed the presence of all TiC, NbC, Zr and Si components in the final powder regardless of the mechanosynthesis time. However, the XRD analysis showed that after 9 and 12 hours of mechanosynthesis, the Zr and Si diffraction lines are completely absent. This occurs due to the dissolution of the Zr and Si elements in titanium and niobium carbides. In addition, it has been established that more than 6 hours are required to synthesize finely dispersed TiC-NbC(Zr, Si) powder. The study results can be useful for optimization of the mechanosynthesis process
Mechanical and Structural Characterization of Laser-Cladded Medium-Entropy FeNiCr-B4C Coatings
Equiatomic medium-entropy alloy (MEA) FeNiCr-B4C (0, 1, and 3 wt.% B4C) coatings were deposited onto an AISI 1040 steel substrate using pulsed laser cladding. Based on an SEM microstructural analysis, it was found that the cross-sections of all the obtained specimens were characterized by an average coating thickness of 400 ± 20 μm, a sufficiently narrow (100 ± 20 μm) “coating–substrate” transition zone, and the presence of a small number of defects, including cracks and pores. An XRD analysis showed that the formed coatings consisted of a single face-centered cubic (FCC) γ-phase and the space group Fm-3m, regardless of the B4C content. However, additional TEM analysis of the FeNiCr coating with 3 wt.% B4C revealed a two-phase FCC structure consisting of grains (FCC-1 phase, Fm-3m) up to 1 µm in size and banded interlayers (FCC-2 phase, Fm-3m) between the grains. The grains were clean with a low density of dislocations. Raman spectroscopy confirmed the presence of B4C carbides inside the FeNiCr (1 and 3 wt.% B4C) coatings, as evidenced by detected peaks corresponding to amorphous carbon and peaks indicating the stretching of C-B-C chains. The mechanical characterization of the FeNiCr-B4C coatings specified that additions of 1 and 3 wt.% B4C resulted in a notable increase in microhardness of 16% and 38%, respectively, with a slight decrease in ductility of 4% and 10%, respectively, compared to the B4C-free FeNiCr coating. Thus, the B4C addition can be considered a promising method for strengthening laser-cladded MEA FeNiCr-B4C coatings. © 2023 by the authors.National Natural Science Foundation of China, NSFC: 52105351; Ministry of Education and Science of the Russian Federation, Minobrnauka: 121102900049-1, 122021000033-2, 122021000036-3This research was carried out within the state assignment of the Ministry of Science and Higher Education of the Russian Federation (themes “Additivity” No. 121102900049-1; “Structure” No. 122021000033-2; and “Spin” No. 122021000036-3) using the equipment of the Collaborative Access Center “Testing Center of Nanotechnology and Advanced Materials” of the IMP UB RAS, and supported by the National Natural Science Foundation of China (Grant No. 52105351)
Production of {\pi}+ and K+ mesons in argon-nucleus interactions at 3.2 AGeV
First physics results of the BM@N experiment at the Nuclotron/NICA complex
are presented on {\pi}+ and K+ meson production in interactions of an argon
beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse
momentum distributions, rapidity spectra and multiplicities of {\pi}+ and K+
mesons are measured. The results are compared with predictions of theoretical
models and with other measurements at lower energies.Comment: 29 pages, 20 figure
The BM@N spectrometer at the NICA accelerator complex
BM@N (Baryonic Matter at Nuclotron) is the first experiment operating and
taking data at the Nuclotron/NICA ion-accelerating complex.The aim of the BM@N
experiment is to study interactions of relativistic heavy-ion beams with fixed
targets. We present a technical description of the BM@N spectrometer including
all its subsystems.Comment: 34 pages, 47 figures, 6 table
Endonuclease from Proteus mirabilis | Endonukleaza Proteus mirabilis.
Two isoforms of nuclease displaying DNase and RNase activities were found in the culture liquid and periplasm of Proteus mirabilis. The enzyme was isolated from the periplasm and then purified to a functionally homogeneous state. The nuclease was equally potent in cleaving denatured and native DNAs by the endonuclease mechanism and was designated Pm endonuclease. The endonuclease was shown to be a temperature-dependent enzyme with a pH optimum of 10.4-10.6, requiring the presence of bivalent metal ions and inhibited by citrate and ethylenediaminetetraacetate
Liquid metal dealloying combined with polymer impregnation as novel promising technology for bioHEA-based implant manufacturing
The paper provides a short review of liquid metal dealloying (LMD) combined with subsequent polymer impregnation as promising technology to synthesize low modulus metal-polymer composites for biomedical applications. The introduction presents the key problems and relevance of the development and synthesis of such materials. The “Theoretical basis” chapter defines the LMD method and the main steps required to activate this process. The fundamental principles of thermodynamics, kinetics and morphology evolution of LMD process are presented here. Due to their favorable mechanical characteristics in the context of biomedical applications, the so-called biocompatible high-entropy alloys (bioHEAs) are proposed as promising candidates for LMD treatment combined with polymer impregnation and, accordingly, the synthesis of novel metal-polymer bioHEA materials
Endonuclease from Proteus mirabilis | Endonukleaza Proteus mirabilis.
Two isoforms of nuclease displaying DNase and RNase activities were found in the culture liquid and periplasm of Proteus mirabilis. The enzyme was isolated from the periplasm and then purified to a functionally homogeneous state. The nuclease was equally potent in cleaving denatured and native DNAs by the endonuclease mechanism and was designated Pm endonuclease. The endonuclease was shown to be a temperature-dependent enzyme with a pH optimum of 10.4-10.6, requiring the presence of bivalent metal ions and inhibited by citrate and ethylenediaminetetraacetate
Development of multicomponent hybrid powders based on titanium and niobium carbides as a promising material for laser cladding
Multicomponent hybrid TiC-NbC(Zr, Si) powder was developed and manufactured by mechanosynthesis in a high-energy vibratory ball mill. High-purity fragmented TiC, NbC, Zr and Si powders were selected and mixed in a ratio of 60:15:10:15 at.%, respectively, to manufacture the above powder. Several modes of mechanosynthesis were chosen for the experiment: 3, 6, 9 and 12 hours. Scanning electron microscopy (SEM) and X-Ray diffraction (XRD) analyzes were used to study the morphology, chemical and phase compositions of the obtained TiC-NbC(Zr, Si) powder. The SEM analysis confirmed the presence of all TiC, NbC, Zr and Si components in the final powder regardless of the mechanosynthesis time. However, the XRD analysis showed that after 9 and 12 hours of mechanosynthesis, the Zr and Si diffraction lines are completely absent. This occurs due to the dissolution of the Zr and Si elements in titanium and niobium carbides. In addition, it has been established that more than 6 hours are required to synthesize finely dispersed TiC-NbC(Zr, Si) powder. The study results can be useful for optimization of the mechanosynthesis process
Endonuclease from Proteus mirabilis | Endonukleaza Proteus mirabilis.
Two isoforms of nuclease displaying DNase and RNase activities were found in the culture liquid and periplasm of Proteus mirabilis. The enzyme was isolated from the periplasm and then purified to a functionally homogeneous state. The nuclease was equally potent in cleaving denatured and native DNAs by the endonuclease mechanism and was designated Pm endonuclease. The endonuclease was shown to be a temperature-dependent enzyme with a pH optimum of 10.4-10.6, requiring the presence of bivalent metal ions and inhibited by citrate and ethylenediaminetetraacetate
Dataset for determining rational taxation value with incompatible criteria of economic efficiency and equity
© 2019 The Authors This article is essentially a dataset necessary for analysing the taxation. The data analysis has allowed to determine the optimal taxation model, when the criteria of economic efficiency and equity are incompatible. The dataset has allowed the use of the method of successive concessions in tax optimization. The practical significance of the dataset lies in the ability to simultaneously improve the efficiency and equity in taxation. The dataset was obtained by using the method of expert estimates. A group of experts was asked to rank the taxes established by the Tax Code of the Russian Federation, in descending order of importance. Only strict rankings were allowed. The consistency of expert opinion was evaluated using the Kendall coefficient of concordance. The data set was supplemented with the expert ranking data of the basic principles of taxation, such as the principle of equity; the principle of certainty and accuracy of taxes; the principle of ease of tax collection for taxpayers; the principle of efficiency; the principle of commitment. The dataset can be used in the future to determine a rational amount of taxation depending on the established criteria