Moving towards a hydrogen economy raises the demand for affordable and efficient catalysts for the oxygen reduction reaction.
Cu-bmpa
(bmpa = bis(2-picolyl)amine) is shown to have moderate activity, ...but poor selectivity for the 4-electron reduction of oxygen to water. To enhance the selectivity towards water formation, the cooperative effect of three
Cu-bmpa
binding sites in a single trinuclear complex is investigated. The catalytic currents in the presence of the trinuclear sites are lower, possibly due to the more rigid structure and therefore higher reorganization energies and/or slower diffusion rates of the catalytic species. Although the oxygen reduction activity of the trinuclear complexes is lower than that of mononuclear
Cu-bmpa
, the selectivity of the copper mediated oxygen reduction was significantly enhanced towards the 4-electron process due to a cooperative effect between three copper centers that have been positioned in close proximity. These results indicate that the cooperativity between metal ions within biomimetic sites can greatly enhance the ORR selectivity.
Combination of three copper redox centers into a single complex and forcing them into close proximity lead to high selectivity for the oxygen reduction reaction towards the formation of water.
•Co25.4Cr15Fe37.9Mn3.5Ni16.8Si1.4 alloy was produced by wire arc additive technology.•The microstructure consists mainly of FCC phase but also has CoCr nano phase.•The alloy has good mechanical ...properties.•The chemical are distributed homogeneously.
This study employed wire arc additive manufacturing (WAAM) to fabricate non-equiatomic Co25.4Cr15Fe37.9Mn3.5Ni16.8Si1.4 high-entropy alloy (HEA). Microstructure, elemental distribution, and mechanical properties were investigated. The fabricated HEA has a dendrite structure composed mainly of the FCC phase and CoCr nanoparticles with 1.5–2.5 nm sizes. Energy-dispersive X-ray spectrometry analysis showed that elements are distributed homogeneously in the alloy. Transmission electron microscopy demonstrated the presence of randomly oriented residual dislocations with the density of 1.2∙1010 cm−2. Compressive and tensile tests showed ductile deformation behavior. The yield strength of the alloy is ∼ 279 MPa; ultimate tensile strength is ∼ 500 MPa, and elongation is ∼ 63%.
•Al2.1Co0.3Cr0.5FeNi2.1 high entropy alloy was obtained by additive manufacturing.•The microstructure consists of dendrite grains and interdendrite areas.•The key phases detected at the submicro-and ...nano-levels are Al3Ni and (Ni, Co)3Al4.•Content of Al and Ni atoms are prevalent above other elements in the alloy.
The Al2.1Co0.3Cr0.5FeNi2.1 high-entropy alloy was a product of wire arc additive manufacturing. The feeding material was a three-core cable with different element compositions: Al – 99.95%; Cr – 20%, Ni – 80%; Co – 17%, Fe – 54%, Ni – 29%. Optical microscopy techniques were applied to study the microstructure of the produced material, which comprised dendrite grains varying from 4 to 15 µm and interdendritic regions. Scanning electron microscopy demonstrated the dendrite grains were generally made of Al and Ni atoms; the interdendritic regions contained Cr and Fe, whereas Co was distributed quasi-homogenously in the material. Transmission electron microscopy detected main phases to be Al3Ni and (Ni, Co)3Al4. An Al3Ni phase is cubic, and a (Ni, Co)3Al4 phase is spherical. 7 to 10 nm (Ni, Co)3Al4 particles were found along the boundaries of submicron (40–100 nm) Al3Ni phases.
The subject. Many shortcomings in the current state of local government and self-government systems are that in the process of forming the institutions of Russian public power, there were not ...evolutionary qualitative changes, but, on the contrary, there were processes of quantitative complication of mechanisms and institutions for the exercise of public power, making the role of the people in administrative processes impossible or insignificant.The experience of pre-revolutionary Siberian local self-government is a proven resource in historical practice for improving the organization of local government, as well as the mechanism of public administration, which was prepared on local, Siberian soil, and was not copied from the socio-political systems of foreign countries.The purpose of the article is to identify principles and features of the peasant self-government in Siberia laid down by the reform of the outstanding Russian statesman Michael Speransky.The theoretical and methodological basis of the research are the categories and principles of materialistic dialectics, formal-logical, systemic, comparative-legal and formal-legal methods.The main results. The conditions of life and traditions of self-governing peasant communities in Siberia made it possible for a very long period, up to the revolutionary upheavals of 1917, to find a solution that freed the crown government from the costs of the lower level of local government and its performance of the functions of administration and court in the Siberian village.Conclusions. Peasant self-government was endowed with state powers and included in the mechanism of state power according to the reform of Michael Speransky.
The RED-100 experiment Akimov, D.Yu; Alexandrov, I.S.; Alyev, R.R. ...
Journal of instrumentation,
11/2022, Letnik:
17, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Abstract
The RED-100 two-phase xenon emission detector has been
deployed at 19-m distance from the reactor core of the Kalinin
Nuclear Power Plant (KNPP) in 2021–2022 for investigation of the
...possibility to observe reactor antineutrinos using the effect of
coherent elastic neutrino-nucleus scattering (CE
ν
NS). The
performance of the main systems of the RED-100 setup at operating
nuclear power plant is described. There is no correlation of the
radioactive background at the experimental setup site with ON and
OFF states of the reactor. The data taking run was carried out at
the beginning of the year 2022 and covered both the reactor OFF and
ON periods.
The combination, under mild conditions, of the methylenecarboxylic-appended tetramercaptotetrathiacalix4arene (TMTCA) derivative 4 , blocked in the 1,3-alternate conformation, with acetate salts of ...octahedral copper( ii ), manganese( ii ), nickel( ii ) and zinc( ii ) leads to the formation, in the crystalline state, of high dimensional coordination networks. Depending on the nature of the used metal cations and bases (pyridine or non-coordinating Et 3 N), six new different high-dimensional coordination polymers have been evidenced, presenting 4 different coordination patterns. All the compounds present a metal/ 4 ratio equal to 2/1. The formation of a 2D grid-like compound ( 4 -Zn 2 (Py) 4 ) and three different pseudodiamondoid-like 3D compounds ( 4 -Co 2 (Py) 6 (H 2 O) 2 , 4 -Ni 2 (Py) 6 (H 2 O) 2 , 4 -Mn 2 (Py) 4 (MeOH) 2 , 4 -Mn 2 (DMF) 2 (MeOH) 4 and 4 -Zn 2 (MeOH) 4 ) is observed.
Using wire-arc additive manufacturing (WAAM), we produced samples of Al–Co–Cr–Fe–Ni high-entropy alloy (HEA) with a grain size of 4–15 µm. Inclusions of the second phase were found along the ...boundaries and in the volume of the grains. The near-boundary volumes of the alloy (volumes located along grain boundaries) are enriched in chromium and iron atoms, the volume of grains is enriched in nickel and aluminum atoms, and cobalt is quasi-uniformly distributed in the alloy. The inclusions of an elongated shape are enriched in chromium, iron, and oxygen atoms and may be carbides. Microhardness, modulus of elasticity, and tribological properties of the alloy are determined and the stretch curves are analyzed. Irradiation of the HEA with a pulsed electron beam is accompanied by the release of grain boundaries from precipitates of the second phase, which indicates the homogenization of the material. High-speed crystallization of the molten surface layer of HEA samples is accompanied by the formation of a columnar structure with a submicrometer-nanocrystalline structure. The electron-beam processing decreases the microhardness of the surface layer of the alloy with a thickness of up to 90 µm, which may be due to the relaxation of internal stress fields formed in the initial material during its manufacture. Irradiation of a high-entropy alloy with an intense pulsed electron beam improves the strength and plasticity of the material, increasing the compressive strength by 1.1–1.6 times.
A coating of high-entropy Cantor alloy FeCoCrNiMn of nonequiatomic composition was formed on a 5083 aluminum alloy substrate by wire-arc additive manufacturing (WAAM). The methods of physical ...materials science were applied to analyze the structure, elemental composition, microhardness, and wear resistance of the coating–substrate system. The deposition of the FeCoCrNiMn high-entropy coating on the 5083 alloy surface is accompanied by the formation of microhardness and elemental composition gradients. Microcracks and micropores were revealed in the cross section of the coating. Microhardness in the volume of the coating is 2.5–3.5 GPa and increases to 9.9 GPa at the boundary with the substrate. In the middle part of the coating, the wear factor is 2.3 × 10
–4
mm
3
/N m; the friction coefficient is 0.7. A transition layer up to 450 µm thick is formed at the interface between the coating and the substrate. We analyzed the elemental composition gradient of the transition layer and noted a high level of chemical homogeneity of the coating. The found doping of the coating with substrate elements (aluminum) leads to the formation of a FeC-oCrNiMnAl high-entropy coating, causing a lamellar structure at the interface between the transition layer and the substrate.
The subject. The article examines the reform of local government in Siberia carried out by the outstanding Russian statesman and reformer M.M. Speransky in the first quarter of the 19th century. The ...purpose of the article is to confirm or disprove the hypothesis that the “Statute on Siberian provincial administration” of 1822 formed the organizational structure of state administration in Siberia for almost a century as well as basis for future codifications of Russian legislation that would carry out by M. Speransky. The methodological basis of the research is combination of objectivity, historicism and alternativeness, which presuppose an unbiased approach in the analysis of the historical problems and a critical attitude towards the sources. The main results, scope of application. The “Statute on Siberian provincial administration” of 1822 was the first systematization of local legislation in the history of Russia. The Statute became the first practical experience in the preparation of a code of laws for M.M. Speransky and his collaborators. The Statute was ahead of the subsequent imperial codification and incorporation of legislation carried out under his leadership. The Speransky’s reform in Siberia in 1822 determined the foundations of the administrative-territorial structure of the Trans-Ural region of the country, which corresponded to the needs of the time. The Statute of 1822 also legitimized the volost public administration of the Siberian state peasants, which was organized in the last quarter of the 18th century. This system of administration put the peasant self-government under more strict control by the district police authorities. Particular attention in the article is paid to the structure, nature and organizational and legal issues of the activities of local government in Siberia. Conclusions. The increased interest in the establishment and development of Siberian regional governance is associated not only with the desire of researchers to look deeper into the past, but also with practical needs. Today it is necessary to research the events and facts of the Siberian past in a new way so as not to repeat old myths and delusions and to prevent the emergence of new ones.
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