Vol 43, No 6 (2017)

The geometrical and topological analysis of the crystal structure of intermetallide ε-Mg₂₃Al₃₀ (ToposPro program) with V = 3098.0 ų and space group R-3 is carried out. The symmetric and topological codes of the cluster self-assembly of the crystal structure are determined: primary chain S₃¹ → microlayer S₃² → microframework S₃³. A new type of nanocluster-precursor of the crystal structure, which is formed on the internal 13-atomic cluster, which represents a template and consists of two bound ridged rings Mg–Al–Mg–Al–Mg–Al with the central Mg atom, is discovered. A quasi-spherical deltahedron shell made from 50 atoms is formed on the template. The center of a K63 cluster occupies the position with the point symmetry 3̅ in the unit cell. There are six neighboring K63 clusters in the local environment of the K63 cluster in the layer. The basic 3D network, which characterizes the location of the gravity centers of the K63 clusters, corresponds to a hexagonal closely packed network (HCP, Mg type) with CN = 12. The localization of two Mg atoms in the pores of the framework is determined.

Information on the valence and coordination states of the daughter ^119mSn atoms formed from the parent ¹¹⁹Sb and ^119mTe atoms at the cation and anion sites of crystalline lead chalcogenides (PbS, PbTe) and vitreous arsenic chalcogenides (As₂S₃, As₂Te₃) is obtained by the method of emission Mössbauer spectroscopy with the parent ^119mTe isotope being in a state of mobile radioactive equilibrium with the daughter ¹¹⁹Sb isotope. It is shown that the ratio of different valence and coordination states of tin atoms in crystals and glasses depends on the time of the preparation of Mössbauer sources. The displacement of a part of the daughter ¹¹⁹Sb atoms from positions of parent ^119mTe atoms as a result of the decay of the latter is demonstrated.

Sm³⁺-doped SrO–Al₂O₃–SiO₂ glass-ceramics with excellent luminescence properties were prepared by batch melting and heat treatment. The crystallization behavior and luminescent properties of the glass-ceramics were investigated. The results indicate that the crystal phase in this system is monocelsian (SrAl₂Si₂O₈). Under the excitation with blue light (475 nm) the Sm³⁺-doped SrO–Al₂O₃–SiO₂ glass-ceramics emit green, orange and red lights centered at 565, 605, 650 and 715 nm, which can be assigned to the ⁴G_5/2 → ⁶H_J/2 (J = 5, 7, 9, 11) electron transitions in Sm³⁺ ions, respectively. With the increase of nucleation/crystallization temperature, the crystallite part rises from 66 to 79%. Besides, by increasing crystallization temperature or concentration of Sm³⁺, the samples emission located at 565, 605 and 650 nm is intensified significantly. We envision that, by fine controlling and combining of these three (green, orange and red) lights in an appropriate proportion, the Sm³⁺-doped glass-ceramics are promising luminescence materials for white light-emitting diodes devices.

Neutron shielding properties of (90 – x)B₂O₃–10ZnO–xBi₂O₃ glass systems (where x = 15, 20, 25 and 30 mol %) were investigated by Monte Carlo simulations (FLUKA and GEANT4) and experiments. Neutron mass removal cross sections, number of inelastic scattering, elastic scattering, and capture interactions were estimated by simulations. ²⁴¹Am/Be neutron source was used for the neutron equivalent dose rate measurements. As a result, produced glass samples have fine neutron shielding capacity.

The results of studies, sol–gel synthesis, and the sedimentation stability of complex multicomponent sol–gel systems of the “silica sol modified with Co(NO₃)₂ · 6H₂O, Al(NO₃)₃ · 9H₂O with α-Al₂O₃ or γ-Al₂O₃ as highly dispersed filler” type are generalized. The physical–chemical processes accompanying the formation of modifying layers on the powder oxide particles are examined. The promising prospects of applying α-Al₂O₃ powders modified with a silicate layer of the composition (wt %) 1.2K₂O · 3Al₂O₃ · 3.2CaO · 12.5Na₂O · 28.1B₂O₃ · 52SiO₂ in the fabrication of ceramic materials with improved strength characteristics are demonstrated.

A new perovskite-like oxide (Rb₂Nd₂Ti₃O₁₀) is synthesized by the ceramic method. Its stability in a humid atmosphere and aqueous solutions of different acidities is investigated. Under these conditions, the formation of hydrated and protonated compounds is revealed. The parameters of the unit cell of the Rb₂Nd₂Ti₃O₁₀ oxide and its derivatives and the degree of rubidium substitution by protons for the obtained protonated phases are determined.

“The means by which enlightened rulers and sagacious generals moved and conquered others, that their achievements surpassed the masses, was advance knowledge. Advance knowledge cannot be gained from ghosts and spirits, inferred from phenomena, or projected from the measures of heaven, but must be gained from men, for it is the knowledge of the enemy’s true situation.”

Sun Tze, Bing Fa, 13 (perhaps 500 BC).

“Nam et ipsa scientia potestas est.” [For knowledge itself is power]

Francis Bacon (1561–1626) (Religious Meditations—Of Heresies).

“I am selling what the whole world wants: power.”

Matthew Boulton (1711–1780) (Letter to Catherine the Great of Russia, offering steam engines for sale).

“Modern industry has established the World Market.”

Karl Marx and Friedrich Engels, (The Communist Manifesto, 1848).

“The fundamental concept in social science is Power, in the same sense in which Energy is the fundamental concept in physics.”

Bertrand Russell (1872–1970) (“Power: A New Social Analysis,” 1938)

Using 3D printing, plastic products with the topology of triply periodic minimal surfaces (TPMS) are prepared and their mechanical properties are studied. It is shown that the strength of the products is sufficient to apply them as sandwich panels and they have promising prospects as anechoic platings.

The kinetics of polycondensation in solutions during the liquid-phase synthesis of ceramic material precursors based on a SrO–B₂O₃–SiO₂ system are studied by spectrophotometry. The ratio between the quantitative content of tetraethoxysilane and the reaction rate of the formation of polymer forms is proved.

The relationship between the number of polymorphic modifications of simple compounds comprising the chalcogenide systems and a tendency toward glass formation in the system is investigated. The interrelation between the sizes of glass formation areas and the number of polymorphic modifications is analyzed.