Electrical and optical characteristics of inert-gas plasmas in spatially nonuniform electrode systems

The characteristics of unipolar and bipolar corona discharges in mixtures He/Ar/Kr, He/Ar/Xe, and He/Kr/Xe at atmosphere pressures in electrode systems of the point-plane and point-grid type distributed along the length. It is shown that bipolar corona discharges can be used in the preionization systems of high-pressure inert-gas-atom lasers. The spectral characteristics of the plasma are investigated, and the dependence of the relative intensity of the radiation in the lines Ar(4s-4p), Kr(5s-5p), and Xe(6s-6p) on the composition and pressure of the working mixtures and on the value of the corona discharge current are determined. Zh. Tekh. Fiz. 67, 15–18 (November 1997)     

The plane contact problem of steady thermoelasticity taking heat generation into account

The plane steady contact problem of thermoelasticity when there is heat generation from friction, which arises when an infinite cylindrical punch moves over the surface of an elastic half-space along its generatrix, is considered. It is assumed that heat exchange between the free boundary of the half-space and the surrounding medium obeys Newton's law, while the condition for ideal thermal contact exists in the region in which the solids interact. The problem is reduced to a system of three integral equations in the heat fluxes and temperature. The effect of the thermal and mechanical properties of the cylinder and the half-space on the main contact characteristics is investigated numerically.     

Low-temperature specific heat of crystalline and amorphous Eu2(MoO4)3

The specific heat C _total of crystalline and amorphous Eu₂(MoO₄)₃ is measured in the temperature interval 4.5–30 K. The amorphous state is obtained by applying pressure ∼7 GPa at room temperature. It is found that the specific heat of the crystal at T⩽7.5 K is described by a cubic function of temperature, while the specific heat of the amorphous sample has a strongly non-Debye character in the entire experimental temperature interval. The curve of C _total for amorphous europium molybdate is analyzed in a model of soft atomic potentials, and it is shown that it agrees well with universal low-temperature anomalies of the specific heat of classical glasses obtained by quenching from the liquid. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 8, 623–627 (25 October 1998)     

Superradiance of polaritons in finite one-dimensional crystals of increasing length: Passage from a dimer to an infinite crystal

Solutions of the dispersion equations for polariton states in finite one-dimensional crystals of arbitrary length are obtained. The appearance and evolution of the radiative and nonradiative polariton branches are traced as the length varies from two monomers to limiting values, above which the spectrum no longer undergoes significant changes. The dependences of the frequencies and radiative widths on the polariton wave vector are found for various orientations of the dipole moment of the quantum transition. The evolution of superradiance as the length of the crystal increases is traced. Some previously unknown significant features of the polariton spectrum are noted particularly the damping of the branch traditionally termed nonradiative as a consequence of emission from the end faces. Fiz. Tverd. Tela (St. Petersburg) 40, 2136–2140 (November 1998)     

Investigation of invariant sets with random perturbations with the use of the Lyapunov function

We consider invariant sets of the form V(t, x) = 0, where V(t, x) is the Lyapunov function of the corresponding deterministic system. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 2, pp. 309–312, February, 1998. This work was partially financially supported by the Ministry of Ukraine for Science and Technology.     

Variational and Hamiltonian models in the dynamics of magnetizable conducting fluid

The variational model and the Hamiltonian canonical equation of motion are updated using the Lagrangian invariant for three-dimensional unsteady adiabatic flows of magnetizable, ideally conducting, compressible inviscid fluid. The results are applied to derive Hamiltonian noncanonical equations of motion in physically defined variables. Translated from Nelineinye Dinamicheskie Sistemy: Kachestvennyi Analiz i Upravlenie — Sbornik Trudov, No. 2, pp. 44–46, 1994.     

Application of synthetic reference materials in the medical radiological research centre

The contents of 21 chemical elements (Ag, Br, Ca, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, P, Rb, Sb, Sc, Se, Sr, Zn, Zr) in synthetic reference materials (SRMs) were compared with those in natural reference materials (NRMs) using short- and long-lived radionuclides. SRMs called synthetic standards (SSs) and synthetic standards, biological (SSBs) were prepared on the basis of phenol-formaldehyde resol resins in the Institute of Physics, Georgian Academy of Science. The NRMs included such IAEA reference materials as H-4 (animal muscle), A-13 (animal blood), H-5 (animal bone), SL-1 (lake sediment), SOIL-7 (soil), A-9 (mixed human diet), and IAEA-153 (milk powder). It was shown that SSB-SRMs possessed good representativity of the 30–50 mg tablets, high precision, operational convenience, and could be recommended for the INAA of a wide range of medico-biological and bioecological objects.     

Nonequilibrium Vibrational Kinetics during Hypersonic Flow of a Solid Body in Nitrogen and Its Influence on the Surface Heat Flux

Plasma Chemistry and Plasma Processing - Nonequilibrium nitrogen dissociation-recombination kinetics in the boundary layer and on the surface of a solid body during hypersonic flow. the subsequent...     

Microencapsulation of DNA Within alginate microspheres and crosslinked chitosan membranes for in vivo application

Calf thymus DNA was microencapsulated within crosslinked chitosan membranes, or immobilized within chitosan-coated alginate microspheres. Microcapsules were prepared by interfacial polymerization of chitosan, and alginate microspheres formed by emulsification/ internal gelation. Diameters ranged from 20 to 500 Μm, depending on the formulation conditions. Encapsulated DNA was quantifiedin situ by direct spectrophotometry (260 nm) and ethidium bromide fluorimetry, and compared to DNA measurements on the fractions following disruption and dissolution of the microspheres. Approximately 84% of the DNA was released upon core dissolution and membrane disruption, with 12% membrane bound. The yield of encapsulation was 96%. Leakage of DNA from intact microspheres/capsules was not observed. DNA microcapsules and microspheres were recovered intact from rat feces following gavage and gastrointestinal transit. Higher recoveries (60%) and reduced shrinkage during transit were obtained with the alginate microspheres. DNA was recovered and purified from the microcapsules and microspheres by chromatography and differential precipitation with ethanol. This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.     

On the conjugate boundary value problem

We study the conjugate boundary-value problem with boundary conditions whose orders can be as large as the order of the differential equation or larger. We construct the Green's function of the problem over the entire space when the separating surface is a hyperplane, and we describe its properties. Bibliography: 6 titles.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 30, 1989, pp. 20–24.