Monolayer (ML)-scale GaN/AlN multiple quantum well (MQW) structures for electron-beam-pumped ultraviolet (UV) emitters are grown on c-sapphire substrates by using plasma-assisted molecular beam epitaxy under controllable metal-rich conditions, which provides the spiral growth of densely packed atomically smooth hillocks without metal droplets. These structures have ML-stepped terrace-like surface topology in the entire QW thickness range from 0.75–7 ML and absence of stress at the well thickness below 2 ML. Satisfactory quantum confinement and mitigating the quantum-confined Stark effect in the stress-free MQW structures enable one to achieve the relatively bright UV cathodoluminescence with a narrow-line (~15 nm) in the sub-250-nm spectral range. The structures with many QWs (up to 400) exhibit the output optical power of ~1 W at 240 nm, when pumped by a standard thermionic-cathode (LaB6) electron gun at an electron energy of 20 keV and a current of 65 mA. This power is increased up to 11.8 W at an average excitation energy of 5 µJ per pulse, generated by the electron gun with a ferroelectric plasma cathode at an electron-beam energy of 12.5 keV and a current of 450 mA.

The health of the components that make up the cables of power lines, and hence their service life, is governed at the micro level by changes in their structure and microstructure. In this paper, the structure and microstructure of aluminum wires of overhead power transmission lines (without a steel core) of different service life from 0 to 62 years have been investigated by quantitative techniques of X-ray diffraction, diffraction of back-scattered electrons, and the densitometric method. Elastoplastic properties of the wires have been tested by the acoustic-resonance method. A decrease in the Al material density Δρ/ρ∼−0.165% was found in the near-surface layer of ∼36 μm depth and in the bulk of the wires with an increase in the service life from 0 to 18 years. The density decrease is associated with the accumulation of microcracks. The following density increase (Δρ/ρ∼−0.06%) in wires with a service life of 62 years is attributed to the formation of ∼0.7 vol.% of crystalline Al oxides in the near-surface layers of the wires. The nature of the change in the elastic modulus, microplastic flow stress, and decrement indicates complex structural changes correlating with the results obtained by diffraction methods.

A method for the growth of high‐quality gallium oxide (β‐Ga2O3) bulk crystals from the melt is developed. The influence of the atmosphere in the process zone on the stability of growth and the quality of Czochralski grown crystals is studied. The structural properties of the crystals obtained are investigated. Samples of gallium oxide substrates are demonstrated. The possibility of growing bulk crystals of solid‐solution oxides (AlxGa1–x)2O3 is tested.

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The observed differences in the structure of native tissue and tissue formed in vitro cause the loss of functional activity of cells cultured in vitro. The lack of fundamental knowledge about the protein mechanism interactions limits the ability to effectively create in vitro native tissue. Collagen is able to spontaneously assemble into fibrils in vitro, but in vivo, other proteins, for example fibronectin, have a noticeable effect on this process. The molecular or fibrillar structure of collagen plays an equally important role. Therefore, we studied the interaction of the molecular and fibrillar structure of collagen with fibronectin. Atomic force and transmission electron microscopy showed that the presence of fibronectin does not affect the native structure and diameter of collagen fibrils. Confocal microscopy demonstrated that the collagen structure affects the cell morphology. Cells are better spread on molecular collagen compared with cells cultured on fibrillar collagen. Fibronectin promotes the formation of a large number of focal contacts, while in combination with collagen of both forms, its effect is leveled. Thus, understanding the mechanisms of the relationship between the protein structure and composition will effectively manage the creation in vitro of a new tissue with native properties.