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The technology of preparing a linear-alkylbenzene-based gadolinium-doped liquid organic scintillator (Gd-LOS) as a target material in reactor antineutrino detectors has been developed. Results of longterm measurements of the light yield of Gd-LOS in contact with acryl and stainless steel are presented, which confirm the compatibility of Gd-LOS with these materials. The measurements were performed for two otherwise identical LOS detectors only differing in wall materials of the sensitive volume: acryl versus stainless steel. The results of measurements over about one year showed almost the same, relatively small decreases in the light yield of both detectors. It is concluded that both structural materials can be used in detector parts contacting with Gd-doped scintillator. Such a long-term parallel comparative test was carried out for the first time.

We studied a possibility of fabricating LaN/B grazing incidence multilayer mirrors for 6.

Highly excited states of 6He are sought in the reactions involved in the absorption of stopped pions by 10,11B nuclei. Several levels in 6He are observed for the first time. A state with Ex ≈ 9.3(2) MeV and Γ ≈ 1.0(4) MeV is seen to form in two reactions: 10B(π−, pt)X and 11B(π−, dt)X. Two states are seen to form in the 10B(π−, pt)X reaction channel at energies above the threshold of 6He decay into two tritons (Ex ≥ 12.3 MeV): one state with Ex = 22(1) MeV, Γ = 2.7(1.4) MeV and the other with Ex = 27.0(8) MeV, Γ = 2.5(1.1) MeV.

The subject of this research is new wood polymer-sand composite and the study of its frost resistance using computer experiment. Industrial waste in the form of sawdust, chips, lumpy waste and polyethylene terephthalate are used as the filler. A computer program has been developed for modelling the structure and physical properties of building blocks from wood polymer-sand composite. The program enables to set (in the windows of the interface form in the program code) geometric and physical parameters of building block and material components, as well as test conditions for cyclic heating and cooling to the maximum temperature during operation. It explores the effect of parameters on internal and surface destruction of building blocks. The program is applicable for a wide range of composite component concentrations, building blocks’ geometric parameters, variety of mechanical and thermal cycling tests. The influence of wood polymer-sand composite formulation on the structure has been studied during thermocyclic testing. The dependences of broken bonds on wood concentration, cartograms of bond breaking of wood polymer-sand composite with a wood concentration from 20 to 80% have been obtained. Recommendations for optimizing the formulation of wood polymer-sand composite blocks are given to minimize bond breaking during thermal cycling.

The influence of unidirectional and alternating torsion on the hardness HV0.3 over the cross section and length of steel wire samples in the annealed and hardened state is determined. It is shown that the hardness varies over the whole cross section and may be different in the middle section and at the clamps. The first two or three torsional cycles have a significant influence on the hardness. Further torsion has little influence.

The principal mass transport models and the ways of their implementation are considered. Some problems associated with the application of numerical methods for mass transport modeling in problems of dissolved chemicals migration at a regional scale are discussed. A new method proposed in this study allows the determination of the space structure of a groundwater flow and the simulation of steady-state convective mass transport.

The iDREAM (industrial Detector for reactor antineutrino monitoring) project is aimed at remote monitoring of the operating modes of the atomic reactor on nuclear power plant to ensure a technical support of IAEA non-proliferation safeguards. The detector is a scintillator spectrometer. The sensitive volume (target) is filled with a liquid organic scintillator based on linear alkylbenzene where reactor antineutrinos will be detected via inverse beta-decay reaction. We present first results of laboratory tests after physical launch. The detector was deployed at sea level without background shielding. The number of calibrations with radioactive sources was conducted. All data were obtained by means of a slow control system which was put into operation.

Given an ideal incompressible heavy irrotational fluid, we consider the exact statement of the problem on gravitational-capillary surface waves of small amplitude travelling along an underwater ridge. We show that, under some requirements on the shape of the bottom and the surface tension, the equations of an ideal incompressible fluid have smooth solutions periodic in the variable directed along the underwater ridge and decreasing exponentially with a small positive exponent in the perpendicular direction.

We consider the problem of perturbing the spectrum of a pseudodifferential operator of a real variable in Hardy-type spaces by a compact operator with a small norm. Under some very general requirements on the operators, we prove the existence theorem for an eigenfunction of multiplicity one and prove that the problem is Fredholm in the L2(R) space. Illustrating this theory, we discuss the linear problem of gravitational-capillary surface waves running along an underwater ridge. Assuming the liquid ideal, incompressible, and vortex-free, we show that the waves along the underwater ridge propagate so that their amplitude decays exponentially with a small positive exponent in the direction transverse to the ridge. Moreover, capillarity plays no essential role in a linear approximation.

The dephasing kinetics of the higher frequency component of the Fermi-resonance dyad ν 1 /2ν 2 (1388 cm −1 ) of CO 2 was studied by means of time-domain CARS in the density range where spectral exchange and Dicke effect play a noticeable role. The spectral exchange manifests itself in the gradual shift to longer delay times of minima and maxima of the beats between different Q -branch components with increasing densities and in the simultaneous beats smoothing. As a result of both the effects, the pulse response was practically exponential at CO 2 densities ⩾ 0.4 Amagat.

Search for isobar-analog states (IAS) of superheavy hydrogen isotopes 5-7H was performed among the high-excited states of helium isotopes 5-7He. The excited spectra were measured in stopped pion absorption by light nuclei. The experiment was performed at low energy pion channel of LANL with two-arm multilayer semiconductor spectrometer. Excited states of 5-7He were observed in three-body reaction channels on 10,11B nuclei. Several excited levels were observed for the first time. 6He excited state with Ex = 27.0(8) MeV observed in 10B(π-,pt)X channel is an IAS candidate for 6H with Er ~ 5.5 MeV. 7He excited state with Ex = 24.8(4) MeV observed in 10B(π-,pd)X, nB(π-,pt)X and nB(π-,dd)X channels is an IAS candidate for 7H with Er ~ 3 MeV.

A channel formed by self-focusing of 30-ps pump pulses of wavelength 1.06 μm and energy of up to 40 mJ in high-pressure hydrogen (with a pressure of up to 120 atm) was probed by second-harmonic pulses delayed in time with respect to the pump pulses. This revealed scattering of efficiency which increased from zero to almost total scattering with increasing delay time. The effect is interpreted as scattering by optical inhomogeneities formed by an acoustic perturbation excited under conditions of a nonuniform temperature distribution along the self-focusing channel.