Polyus Research Institute of M.F.Stelmakh (Russia)

The article examines the practice of misinforming relatives of individuals executed by sentencing of the NKVD «troikas» and the Military Collegium of the Supreme Court during the Great Purge through oral notifications of the sentence of 10 years of imprisonment without the right of correspondence. It is demonstrated that the documents regulating this practice ignore the existence of the NKVD Commission and the Prosecutor of the USSR; the application of such a practice was bound to create irresolvable conflicts, since some of the death sentences issued by the Military Collegium were openly published. The testimonies from relatives of the executed indicate varying imprisonment terms, which would be impossible in the case of a uniformly organised disinformation campaign. The study shows that information about such misinformation emerged during Vinnytsia exhumation of 1943, when the Nazis attempted to present the bodies of Jews who had been killed by them in 1941-42, as the victims of the NKVD executions in 1937-38. Having no evidence of the NKVD’s involvement in the deaths of the exhumed, the occupying authorities had to state that the relatives of those executed by the NKVD had been verbally informed of ”10 years without the right to correspondence” sentence. The procedure of “identification” of the corpses was built on the basis of those oral statements. The article concludes that in reality, no organised campaign of misleading relatives of those executed through oral notifications took place in the USSR. All documents related to this practice require thorough verification.

The possibility of using a laser gyroscope with circular polarization of waves and a Zeeman frequency biasing for conducting various types of geophysical measurements is investigated. The first results of measuring the Earth’s rotation rate by a Zeeman laser gyroscope with a perimeter of 20 cm in the underground laboratory of the Baksan Neutrino Observatory, Institute for Nuclear Research of the Russian Academy of Sciences (BNO INR RAS), are presented under conditions of maximum exclusion of external influencing factors—with thermal stabilization, shielding of electromagnetic fields, and minimization of seismic noise. An increase in the registration sensitivity by an order of magnitude (up to 10–3 deg/h) is noted compared to previously experiments in the urban ground-based laboratory. The possibility of continuous operation of the installation in a remote mode for more than 6 months is shown.

The paper presents the results of investigating the static characteristics of avalanche photodiodes (APD) fabricated from an InP/InGaAs heterostructure grown by metal organic vapor phase epitaxy, followed by single-stage zinc diffusion from a metal organic source of diethylzinc. The fabricated APDs have demonstrated at room temperature a breakdown voltage of 53 V, dark currents of maximum 0.7 nA, and a capacitance of 0.55 pF at 0.9 times the breakdown voltage. The spectral sensitivity of the fabricated APD was at least 0.8 A/W at a wavelength of 1550 nm. The temperature coefficient of the APD breakdown voltage was 85 mV/K.

We present a study of high-power quantum-cascade lasers (QCL) for 8 μm spectral range with active regions of latticematched to InP substrate and strain-balanced designs. The use of the strained quantum well/barrier pairs made it possible to increase the energy barrier between the upper laser level and continuum by ~ 200 meV. Our experiments show that utilization of the strain-balanced design of the active region makes it possible to more than double the characteristic temperature T₀ to 253 K from 125 K for the lattice-matched design. In pulsed mode, QCLs with strain-balanced active region demonstrated high efficiency of 12% and high output optical power of 21 W (over 10 W per facet). This is the highest value of the optical power demonstrated to date in 8 μm spectral region to the best of our knowledge.

We analyze the characteristics of semiconductor emitters based on separate-confinement double heterostructures with quantum wells with different configurations of waveguide layers. Lasers with narrow and broad waveguides are considered as applied to the problem of increasing the output power. Semiconductor emitters with undoped and doped waveguide layers are compared. We consider lasers with ultranarrow and broad strongly asymmetric waveguides. It is shown that the reduction of series and thermal resistance reduces the self-heating of lasers and increases the output power and efficiency. The prospects of using the epitaxial integration for designing lasers with several tunnel-coupled emitting sections for increasing the output power and luminosity are considered. The possibility of constructing monolith-integrated thyristor lasers combining the emitting section and an electron switch in a single crystal is demonstrated.

The paper describes the influence of gold and gold mining industry on Russian monetary regulator policy during last year. The role of an important export commodity class, such as gold, in dedollarization of the system of international money settlements is highlighted.

In late 2021, the potential to extend a very large open pit was investigated. The mine has a high-resolution structural and hydrogeological model, permitting construction of a large-strain, discontinuum, closely coupled hydromechanical finite element model with a much better than inter-ramp scale representative elementary volume. In models of this type, the hydrogeological parameters and constitutive model are also non-linear, so that conductivity and the Biot coefficient are expressed as functions of the modelled plastic strain tensor. Additionally, because extreme seasonal variations occur in surface water flows, the models included simulation of the flow of near-surface water and a novel method for capturing the inflow of this water into the dilated rock mass, joints and faults, thus permitting estimation of active water pressure. Active water pressure in the damaged and dilated rock mass and rock mass defects is a major driver of instability in slopes, but it is not often simulated, especially in models of this scale (30 pit stages, over 100M degrees of freedom). The addition of this mechanism for water-driven instability and the high-resolution model setup permitted very close calibration of modelled and measured movements, enabled measurement of hydraulic head and failures using many years of data, and facilitated a statistical analysis of the correlation of failure and modelled movement and strain. This was undertaken using a cell evaluation method (CEM; Beck & Brady 2001) , resulting in a true probability function using model outputs with an estimate of error and resolution. The project resulted in a comprehensive validation of the model for the mine, a useable probabilistic criterion for slope failures ranging from small to medium, and a hypothesis ranging from the extrapolation of early slope stability data to the prediction of larger failures. There are also lessons regarding the necessary resolution of hydromechanical assumptions and inputs for high-quality prediction of slope instability, particularly the need to capture the influence of rock mass and rock defect dilation and degradation on flow and pressure.