Silicon Film Deposition Using a Gas-Jet Plasma-Chemical Method: Experiment and Gas-Dynamic Simulation

This paper presents the results of an experimental study, numerical calculation, and analysis within the framework of a gas-dynamic model of silicon film deposition by a gas-jet plasmachemical method. A numerical model of gas mixtures flowing out of an annular nozzle unit and into a reactor is developed, and it allows one to determine a film thickness distribution over the surface of substrates placed in the reactor and satisfactorily describes the experimental data obtained.     

X-ray diffraction study of mesogenic 4-methoxyphenyl-4′-n-nonyloxybenzoate

4-methoxyphenyl-4′-n-nonyloxybenzoate have been investigated by single crystal X-ray structural analysis. Crystal packing of the compounds does not represent a precursor of the mesophse although the typical for liquid crystal compounds separation of crystal packing on aromatic and aliphatic areas is observed here. Possible reason for monotropic properties are discussed.     

Dependence of the Methane Decomposition Factor in Cold Electron-Beam Plasma upon Input Power

A device for creating a cold nonequilibrium electron-beam plasma in a supersonic gas flow has been developed. A method proposed for generating this plasma is described. It has been established that methane is activated by direct electron impact in electron-beam plasma under specified conditions. It has been shown that applying an external electromagnetic field leads to a significant increase in the methane decomposition factor due to the involvement of secondary, low-energy beam electrons accelerated in the electromagnetic field.     

Modern application packages for rigorous solution of problems of light propagation in anisotropic layered media: II. Optically active crystals

The matrix Δ suggested by Berreman for optically active crystals of various symmetry classes has been calculated with the use of the Mathematica-4.1 package. It is shown that the eigenvalues of this matrix are the refractive indices, whereas its eigenvectors determine the polarization states of eigenwaves propagating in the crystal. The relation between the components of the gyration tensors obtained on the basis of various constitutive equations is established. The essential differences in the optical activity described on the basis of these equations are also discussed.     

Invariant ordering on the simply connected covering of the Shilov boundary of a symmetric domain

The Shilov boundary of a symmetric domain D = G/K of tube type has the form G/P, where P is a maximal parabolic subgroup of the group G. We prove that the simply connected covering of the Shilov boundary possesses a unique (up to inversion) invariant ordering, which is induced by the continuous invariant ordering on the simply connected covering of G and can readily be described in terms of the corresponding Jordan algebra.     

Rheological evidence for the existence of subphases in the liquid crystalline 4-n-alkoxybenzoic acids

The rheological behaviour of the homologous series, the alkyloxybenzoic acids, has been studied at steady flow and small amplitude oscillatory shear. The temperature dependencies of the viscosity were compared with differential scanning calorimetry data in order to estimate pretransitional phenomena in mesophases. The values of the viscosity and flow activation energy (E) can be indicative of the mesophase state. 4-n-pentyloxybenzoic acid yields a classic nematic (N) phase while the next homologues show a cybotactic nematic phase having a higher E value. The N phase is a Newtonian fluid of lower viscosity than that of the isotropic phase. The cybotactic nematic phase by its rheological properties takes an intermediate position between the N phase and a smectic C (SmC) phase. The SmC phase is a viscoelastic and viscoplastic medium. The SmC phase of 4-n-octyloxy-, 4-n-nonyloxy-, 4-n-decyloxy- and 4-n-dodecyloxybenzoic acid can exist in high- and low-ordered states. The more ordered smectic phase is characterised by higher stiffness, viscosity and yield stress than those of the less ordered. The SmC phase of 4-n-hexadecyloxybenzoic acid is characterised by the only state with unstable value of apparent viscosity. The phase state and the transition temperature can be dependent on the thermal history of the sample and a mechanical shear.     

Multipurpose implanter for high technology development

To provide basic operations of semiconductor and radiation materials technologies, a multipurpose implanter with intense ion beams was developed at the Institute of Nuclear Physics. The generated beamparameters are as follows: ions are H⁺, O⁺; C⁺; the ion energy is up to 200 keV; the beam current is up to 2 mA; and the implantation mode is continuous. The size of the target to be processed can reach 76 × 76 mm². During the implanter operation, the target chamber vacuum reaches 10^?4 Pa. The entire process of target irradiation is fully automated.     

High-rate deformation and fracture of fiber reinforced concrete

This paper presents the results of dynamic compression and splitting-tensile tests of cardiff fiber reinforced concrete (CARDIFRC) composite using the Kolsky technique and its modification. The strength and deformation characteristics of fiber-reinforced concrete were determined experimentally at high strain rates. The mechanical characteristics were found to depend on the strain rate and stress rate. A uniform interpretation of the rate effects of fracture of the tested fiber-reinforced concrete is given on the basis of a structural-temporal approach. It is shown that the time dependences of both the compressive and tensile strengths of fiber reinforced concrete are well calculated using the incubation time criterion.     

Acceleration mass spectrometer of the Budker Institute of Nuclear Physics for biomedical applications

An accelerator mass spectrometer (AMS) made at the Budker Institute of Nuclear Physics (BINP), Siberian Branch, Russian Academy of Sciences, is installed in the Geochronology of the Cenozoic Era Center for Collective Use for the carbon 14 dating of samples. Distinctive features of the BINP AMS include the use of a middle energy separator of ion beams, magnesium vapor target as a stripping target, and a time-of-flight telescope with thin films for accurate ion selection. Results of experiments measuring the radiocarbon concentration in test samples with radiocarbon labels for biomedical applications are presented.