Magnetic and magneto-thermal properties of ferrimagnetic alloys (Er1-xYx)(Co0.84Fe0.16)2and their dependence on the orientations of resultant and sublattice magnetizations.

In this paper structure, magnetic and magneto-thermal properties: magnetic entropy change (ΔSm) and refrigeration capacity (q) of Er1-xYx(Co0.84Fe0.16)2alloys (x= 0, 0.2, 0.4, 0.6, 0.8, 1) in magnetic fields up to 90 kOe in a temperature range of 5-360 K are investigated. An analysis of temperature dependences of magnetization (σ) and high-field susceptibility (χhf) showed that in these compounds, three different ferri- and a one ferromagnetic structures are consequently realized. Concentration dependences of magnetic moment at 5 K (µf.u.), Curie temperature (TC), residual magnetization (σr) and coercivity (Hc) have been shown to have an extreme at intermediate Y concentration. The character of temperature dependence of magnetic entropy change (ΔSm(T)) depends on the composition and originates from the type of magnetic structure of the compound and the mutual orientation of R- and 3d- element sublattices magnetization with respect to the resulting one. In compounds withx= 0.6 andx= 0.8 temperature regions with different signs of ΔSmare observed, reflecting the change of dominating R- or 3d- sublattice in the resulting magnetization.

Scale invariance and universality in a cold gas of indirect excitons.

We address, theoretically, the puzzling similarity observed in the thermodynamic behavior of independent clouds of cold dipolar excitons in coupled semiconductor quantum wells. We argue that the condensation of self-trapped exciton gas starts at the same critical temperature in all traps due to the specific scaling rule. As a consequence of the reduced dimensionality of the system, the scaling parameters appear to be insensitive to disorder.

Optical pump-probe detection of manganese hyperfine beats in (Cd,Mn)Te crystals.

Optical pump-probe experiments reveal spin beats of manganese ions in (Cd,Mn)Te, due to hyperfine and crystal fields. At "magic" orientations of the magnetic field, the effect of local crystal field is strongly suppressed. In this case, the spin precession of Mn(2+) embedded in the lattice approaches the precession expected for the free ion. Following optical excitation, regular spin pulses show up, revealing the one-to-one correspondence between precession frequency and Mn(2+) nuclear spin state. The period of the spin pulses accurately determines the hyperfine constant |A|=705 neV. The manganese spin coherence time up to T(2)(Mn)≃15 ns is measured for a manganese concentration x=0.0011.

Thermodynamic model of the macroscopically ordered exciton state.

We explain the experimentally observed instability of cold exciton gases and the formation of a macroscopically ordered exciton state in terms of a thermodynamic model accounting for the phase fluctuations of the condensate. We show that the temperature dependence of the exciton energy exhibits fundamental scaling behavior with the signature of the second order phase transition.

[Deterministic chaos in the dynamics of biomembrane ion channel current].

Within the framework of the theory of deterministic chaos, a nonlinear first-order differential equation with delay and relaxation with periodic influence on channel current for the parameter of order (deviation of channel current from the equilibrium value) was obtained. The numerical solutions of the equation indicate a chaotic dynamics of the order parameter and conformation potential of the channel protein with positive Lyapunov indices. By integration in the time interval between the "jumps" of ions through energy barriers of the channel protein, a mapping was obtained that also results in chaotic solutions realized in experiments. Basic kinetic characteristics of ionic channels for the mapping were obtained: the probability for the channel to be in the open state, P0, and the mean duration of a pack of current pulses depending on controlling parameters. Algorithms for constructing bifurcation diagrams with the transition to chaos and for determining Lyapunov indices and Kholmogorov entropy, pulsation spectra, and other parameters of chaotic dymanics were developed.

[A method for decreasing the volume of the solution of radium salts used for radon therapy]. / Sposob umen'sheniia ob''ema rastvora solei radiia, ispol'zuemykh dlia radonoterapii.

A procedure has been proposed to reduce the volume of radon salt in the radon generators used in the laboratories for artificial preparation of radon procedures. This permits work to be done remotely under the conditions of a radon laboratory without manipulations just with radon solution and without radioactive waste.

[Increasing the radon concentration in natural water without the use of radium preparations]. / Ob uvelichenii kontsentratsii radona v prirodnoi vode bez primeneniia preparatov radiia.

The method of increasing radon concentrations in natural radon water without radon generators is based on radon redistribution between various water volumes, water and air. Radon is extracted from hot radon water with subsequent solution in cold radon water. This method enables the specialists to increase radon concentrations 2-3-fold using a simple enriching unit.

[A method for preparing air-radon mixtures from radon water by decompression]. / Sposob prigotovleniia vozdushno-radonovykh smesei iz radonovoi vody metodom dekompressii.

The technique has been tested of intensive radon dissolving in water usable for therapeutic procedures. The gas is provided from the soil or ore radon-containing air. The dissolving occurs under artificial growth of radon concentration in gas atmosphere by its compression at the time of mixing with cooled water in accordance with classical laws of gas distribution between liquid and gas phases in closed space. Practical utilization of the above method allows preparation of therapeutic water media without radium preparations and more effective use of radon produced in radon laboratories, thus significantly reducing radon waste and environment pollution.

[The correction of the functional activity of alveolar macrophages in inducing a primary immune response in influenza]. / Korrektsiia funktsional'noi aktivnosti al'veoliarnykh makrofagov v induktsii pervichnogo immunnogo otveta pri grippe.

The functional activity of alveolar macrophages obtained from mice, both healthy and infected with influenza virus A/Aichi 2/68 (H3N2), as manifested by their capacity to initiate the development of primary immune response to sheep red blood cells and Escherichia coli lipopolysaccharide after the transfer of these macrophages to intact syngeneic recipients was studied. The capacity of alveolar macrophages to perform antigen-presenting functions in the induction of humoral immune response was shown, and at the same time the development of experimental influenza infection was found to essentially decrease these properties. The injection of the immunomodulating agent diuciphon into experimental mice somewhat enhanced the immune response after the syngeneic transfer of alveolar macrophages from infected mice to intact recipients.

[Ecological protection against volley discharges of radon from the installations of radon laboratories]. / Ekologicheskaia zashchita ot zalpovykh vybrosov radona iz ustanovok radonovykh laboratorii.

The authors analyzed the amount of radon waste and decay products discharged into atmosphere from radon laboratory units. Underlying principles of the design of radon escape monitoring and protection devices are considered. Relevant rating and the parameters of the apparatus developed to considerably limit the isotopes escape are presented. The apparatus is adjusted for current devices making radon concentrates.