The effect of spatial field distribution on two-mode lasing in a spherical microparticle

It is shown that two steady-state two-mode lasing regimes resulting from nonlinear coupling of the modes and spatial overlap of their fields may exist above the first lasing threshold. With increasing pumping power in one of the modes, the region of their existence is larger the larger the difference in intensities of the spatial structures of the modes.     

Structure and Characteristics of the Fracturing of Layered Ni-Al Composites

Layered composite materials with alternating layers of a solid solution of aluminum in nickel and intermetallic Ni-Al compounds are obtained. The evolution of the composite structures depending on the heat-treatment conditions is discussed. The mechanical tests of materials highlight a fracture toughness of up to 23 MPa m^1/2, a strength of up to 1800 MPa at room temperature and 150–480 MPa in the range 1000–1150°C.     

Adaptive X-Ray Optical Elements Based on Bending Piezoactuators: Possibilities and Prospects of Practical Application

Crystallography Reports - The possibilities of a new class of adaptive X-ray optical elements based on bending piezoelectric actuators for practical implementation of time-resolved experiments...     

Superconductivity and structure of the multilayer Cu/Nb/Nb-Ti nanocomposites

The multilayer composite tapes containing layers of superconducting alloy of niobium with 31 or 50 wt % of Ti separated by niobium layers were investigated. The thickness of a layer is from ∼140 to ∼10 nm. Composites were produced by three-step rolling of multilayer packages. Effective fixation of the superconducting vortex filaments occurred at the interlayer boundaries of Nb-NbTi, as evidenced by the large anisotropy of the critical current density. The second critical magnetic field was found also dependent on the orientation of the plane of rolling of the composite relative to the external magnetic field, and decreases with decreasing thickness of the layers.     

Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.     

Porous metallic substrates for superconducting coatings

By an example of porous metal tubes and thin plates prepared from the stainless steel powder a simple method is described of preparation of porous metallic substrates for superconducting coatings. The tubes outer diameter is 12 mm, length up to 300 mm, wall thickness about ∼1.5 mm. The plate size is 85×85 mm, thickness 1 mm. We used the classic method of powder metallurgy, without any fillers. After sintering, the tube had a density 2.5–3.4 g cm⁻³ and open porosity 55–65%. The microstructure of the tubes and plates surfaces and breaks was studied using scanning electron microscopy. The porous tubes were prepared also from powdered copper, nickel, titanium, and chromium, as well as from mixtures of stainless steel and copper, nickel and pseudoalloy Cu(30%)-Cr. The first coatings with superconducting compound MgB₂ were prepared.     

A power-supply control system for the NESTOR X-ray generator

The work considers the control system of magnetic components of the NESTOR Compton back-scattering X-ray generator. The control system allows integration of the control and visualization modules of other subsystems of the generator. The described system was experimentally tested, and during the test a beam was inputted into the physical volume of the NESTOR storage element.     

Redox sorption in metal–ion-exchanger nanocomposites upon electrochemical polarization

A conjugated macrokinetic problem is solved for two moving boundaries of chemical reactions during redox sorption in metal–ion-exchange nanocomposites under conditions of current flow. Numerical solutions to the multipoint boundary value problem indicate that the impact of the current includes a slowing of front migration associated with distinct stages of the chemical reaction between metal nanoparticles and oxygen due to electrochemical reduction, a reduced surface concentration of the active sorbate (oxygen), and an increased degree of redox sorption. An increase in the contribution from the electrochemical component and a transition to external diffusion control are observed as the current density grows.     

The structure and adsorption properties of amorphous linear-chain carbon

A highly effective adsorbent based on linear-chain carbon is studied by infrared spectroscopy, Raman spectroscopy, X-ray microanalysis, and X-ray diffraction analysis. The structure and the properties of amorphous linear-chain carbon are investigated.     

Analysis of Rayleigh–Taylor mixing-zone development by means of a multilayer perceptron

The problem of Rayleigh–Taylor (RT) instability is considered. The research technique is based on the statistical treatment of variants of the RT instability numerical simulations. Such treatment can be performed by means of neuron networks. To predict the mixing-zone width and embedded mass at arbitrary instants, a multilayer perceptron model is applied. The initial shape of a heavy–light liquid interface is used to make the prediction.