[en] The current state of research on the free oscillations of the sun is reviewed. Observational data on oscillations with periods from 5 to 160 min published through the end of 1980 are described. The interpretation of these data in connection with research on the internal structure of the sun is discussed. A theory of the free oscillations in the linear adiabatic approximation is described; differential rotation is taken into account. The principles for classifying the theoretical normal modes are discussed. The problem of the excitation of the solar oscillations is outlined. The theoretical normal-mode spectra of Jupiter and Saturn are discussed

[en] While the primary purpose of the BIR and BIGR reactors is to generate neutron and gamma irradiation pulses, they were also used regularly to conduct experiments aimed at enhancing the parameters of radiation of pulsed reactors, making them safer, and examining various topics in neutron physics. The present review addresses the following issues: long-term performance of BIR and BIGR in the mode of self-adjustment of power; generation of fission pulses when the rod passes through the core; coupled systems (BIR + a subcritical assembly); experiments with ultracold neutrons at the BIGR reactor; and fast-acting emergency protection and the pulse delay time in the BIR reactor with a weak neutron source in the core.

[en] We address the numerical performance of the successive overrelaxation technique (SOR) in the restoration of astronomical images. Local analysis of the convergence rates reveals resonant properties, with convergence enhancement at a spatial frequency which is determined by the SOR relaxation parameter τ. The analysis can serve as a guide for the practical choice of the relaxation parameter(s), which governs the regularization properties of the SOR algorithm. One particular prediction is that in typical implementations, fast image deblurring requires deep underrelaxation (τ << 1). This theoretical result allows us to better understand the productive properties of underrelaxation, which have been discovered in earlier work. Comparison of SOR in artificial inversions with conjugate gradients and related methods (GMRES) indicates that a solution of similar or better quality may be obtained in a comparable or smaller number of iterations. Restricting the solution with non-negativity constraint (+SOR) enhances both the quality of the solutions and the convergence rate. Theoretical analysis of the convergence properties of +SOR, however, remains a challenge which cannot be addressed by the simple analysis implemented in this paper

[en] Perturbational analysis of the p-mode coupling at high degree l, induced by the solar differential rotation is extended to include, into a unified theoretical description, the effects of global meridional circulation. The predicted observational signatures of the meridional circulation in the global p-mode measurements are briefly discussed.

[en] A reactor with a destructible core (RIR reactor) generating a pulse with an output of ~1.5 × 10¹⁹ fissions and a full width at half maximum of ~2.5 μs was developed and tested at VNIIEF. In the course of investigation, a computational-experimental method for laboratory calibration of the reactor was created and worked out. This method ensures a high accuracy of predicting the energy release in a real experiment with excess reactivity of ~3β_eff above prompt criticality. A transportable explosion-proof chamber was also developed, which ensures the safe localization of explosion products of the core of small-sized nuclear devices and charges of high explosives with equivalent mass of up to 100 kg of TNT.