[en] Parallax effects in laser Doppler spectroscopy, associated with the variation of the scattering angle during motion of a particle through the probed volume, were investigated by a numerical simulation method based on the Mie scattering theory. It was found that, in general, the shifts of the spectral profile parameters (the average frequency, broadening, asymmetry, and kurtosis) become significant as the parallax number N_ψα=(2/π)ψα (ψ is the angular size of the probed volume, α = πd/λ is the relative particle diameter) increases. The anomalous ranges of the parameters of the particle and of the optical system, in which marked distortions (such as the polymodal nature and the splitting of the spectral profile) are observed even for a low parallax number (N_ψα || 1), were discovered. (laser applications and other topics in quantum electronics)

[en] It is necessary for the power-consuming magnetic components of channels for beam transport in accelerators of charged particles be supplied with direct current. An individual power source is typically applied for each group of identical components. A variant of the simultaneous supply of several groups of magnets from a single medium-power source using auxiliary current shunts of different types is given by the example of a LEPTA positron storage ring. One version of using this technology with MW-power sources for a phasotron accelerator is developed. The efficiency of putting this technology into practice with the application of start-stop regimes for the phasotron is estimated.

[en] Enthalpies of the dissolution of DL-α-alanylglycine (AlaGly), DL-α-alanyl-DL-α-alanine (AlaAla), DL-α-alanyl-DL-α-valine (AlaVal), and DL-α-alanyl-DL-norleucine (AlaNln) in an aqueous solution of sodium dodecyl sulfate (SDS) at SDS concentration of m = 0–0.07 mol kg⁻¹ and temperature Т = 298.15 K are measured via calorimetry. The standard values of the enthalpy of dissolution (Δ_solH^m) and the transfer of dipeptides (Δ_trH^m) from water to aqueous SDS solutions are calculated using the experimental data. The dependences of Δ_solH^m and Δ_trH^m the SDS concentration at a constant concentration of dipeptide are established. Thermochemical characteristics of the transfer of AlaGly, AlaAla, AlaVal, and AlaNln in the investigated range of SDS concentrations are compared. The results are interpreted by considering ion–ion, ion–polar, and hydrophobic–hydrophobic interactions between SDS and dipeptide molecules.

[en] The enthalpies of dissolution of N-methylglycine in water + ethanol, water + (1-propanol) and water + (2-propanol) are determined via calorimetry at an alcohol concentration of x₂ = 0–0.25 mole fraction. The standard values of enthalpies of dissolution (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{sol}}{H}^{\circ <!--\; ???\; -->}$) and transfer (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{tr}}{H}^{\circ <!--\; ???\; -->}$) of N-methylglycine from water to solution are calculated. The effect the structure and properties of N-methylglycine and the composition of a water–alcohol mixture have on N-methylglycine’s enthalpy characteristics is examined. The enthalpy coefficients of pair interactions (h_xy) between N-methylglycine and alcohol molecules are calculated. They have positive values and grow in the series ethanol (EtOH) < 1-propanol (1-PrOH), < 2-propanol (2-PrOH). A comparative analysis is performed of the enthalpy characteristics of dissolution and transfer of N-methylglycine and the analogous characteristics of glycine and DL-α-alanine in similar mixtures.

[en] The enthalpies of solution of 4-hydroxy-L-proline and L-phenylalanine in binary mixed aqueous solvents containing acetonitrile (AN), 1,4-dioxane (1,4-DO), or acetone (AC) at mole fractions of 0 to 0.25 are determined at T = 298.15 K via isothermal calorimetry. The standard enthalpies of solution (Δ_solH°) and transfer (Δ_trH°) of 4-hydroxy-L-proline and L-phenylalanine from water to mixed aqueous solvents are calculated using the experimental calorimetric data, as are the enthalpy coefficients of paired interactions (h_xy) between the molecules of the investigated amino acids and the organic solvents. The effects the mixed aqueous solvent composition and the structure of the organic solvent molecules have on the enthalpies of solution and transfer for the investigated amino acids are considered. The correlation between the enthalpy of solution of the amino acids and the electron-donating properties of the organic solvents in the mixed aqueous solvent systems is established.

[en] The intellectual power supply and control system is presented for the group of electromagnetic lenses in the phasotron-beam transport channel supplied from one power supply source. An intellectual power supply and control system is proposed to minimize power consumption upon the redistribution of the lens currents between the main power supply and additional local regulation power supply sources.

[en] The enthalpies of N-methylglycine dissolution in aqueous solutions of acetonitrile (AN), 1,4-dioxane (DO), acetone (AC), and dimethylsulfoxide (DMSO) at a mole fraction of an organic solvent x₂ of 0‒0.25 and T = 298.15 K. The results of the experiment were used to calculate the standard values of the enthalpies of dissolution (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{sol}}{H}^{\circ <!--\; ???\; -->}$) and transfer (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{tr}}{H}^{\circ <!--\; ???\; -->}$) of N-methylglycine from water to the mixed solvent, as well as the enthalpy coefficients of pairwise interactions (h_xy) of N-methylglycine with organic solvent molecules. The influence of the composition of an aqueous–organic mixture and the structure of organic solvents on the enthalpy characteristics of dissolution and transfer of N-methylglycine is considered. The effect of energetics of intermolecular interactions between the components of a mixed solvent on intermolecular interactions of N-methylglycine with co-solvent molecules is estimated. The main properties of the cosolvent that significantly affect the energetics of interaction with N-methylglycine molecules in an aqueous solution are determined—polarity/polarizability and the electron-donating ability of the cosolvent.

[en] The dissolution enthalpies (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{sol}}{H}_{\text{m}}$) of DL-α-alanyl-DL-α-valine (AlaVal) and DL-α-alanyl-DL-α-norleucine (AlaNln) in aqueous solutions of dodecyl sulfate (SDS) at SDS concentration of m_SDS = 0.05 mol·kg⁻¹ and peptide concentration m = 0.010 to 0.025 mol·kg⁻¹ at T = 298.15 K were measured via calorimetry. The results obtained have been used to calculate the transfer enthalpies (${\mathrm{\Delta <!--\; ??\; -->}}_{\text{tr}}{H}_{\text{m}}$) of AlaVal and AlaNln from water into (water + SDS) micellar solution. Thermochemical characteristics of the transfer of AlaVal, and AlaNln in the investigated range of peptide concentrations are compared. The results are interpreted by considering ion–ion, ion–polar, and hydrophobic–hydrophobic interactions between the dipeptides and SDS micelles.

[en] The delayed-neutron yield from thermal-neutron-induced fission of the ²³⁷Np nucleus was measured using a sample periodically exposed to a pulsed neutron beam with subsequent detection of neutrons during the time intervals between pulses. The experiment was realized on an Isomer-M setup mounted in the IBR-2 pulsed reactor channel equipped with a mirror neutron guide. The setup and the experimental procedure are described, the background sources are thoroughly analyzed, and the experimental data are presented. The total delayed-neutron yield from ²³⁷Np fission induced by thermal neutrons is ν_d = 0.0110 ± 0.0009. This study was performed at the Frank Laboratory of Neutron Physics (JINR, Dubna)

[en] The first experimental evidence is presented that the use of a chirped volume Bragg grating (CVBG) as a cavity mirror of a Q-switched picosecond Nd : YAG laser with self-mode-locking leads to significant changes in the temporal parameters of the laser output. Measurements have been performed at two positions of the CVBG: with the grating placed so that shorter wavelengths reflected from its front part lead longer wavelengths or with the grating rotated through 180°, so that longer wavelengths are reflected first. In the former case, the duration of individual pulses in a train increased from ∼35 to ∼300 ps, whereas the pulse train shape and duration remained the same as in the case of a conventional laser with a mirror cavity. In the latter case, the full width at half maximum of pulse trains increased from ∼70 ns (Nd : YAG laser with a mirror cavity) to ∼1 ms, and the duration of individual pulses increased from 35 ps to ∼1.2 ns, respectively, which is more typical of free-running laser operation. (laser crystals and braggg ratings)