Each finite group is a symmetry group of some map (an “Atom”-bifurcation)

Maps are studied, i.e., cell decompositions of closed two-dimensional surfaces, or two-dimensional atoms which encode bifurcations of Liouville fibrations of non-degenerate integrable Hamiltonian systems. Any finite group G is proved to be a symmetry group of an orientable map (of an atom). Moreover, one such map X(G) is constructed algorithmically. Upper bounds are obtained for the minimal genus Mg(G) of an orientable map with the given symmetry group G and for the minimal number of vertices, edges, and sides of such maps.     

Presentation for the Partial Dual Symmetric Inverse Monoid

We give a monoid presentation in terms of generators and define relations for the partial analogue of the finite dual symmetric inverse monoid.     

Atmospheric gamma-ray and neutron flashes

Gamma-ray pulses are calculated from 2D numerical simulations of an upward atmospheric discharge in a self-consistent electric field using the multigroup approach to the kinetics of relativistic runaway electrons (REs). Computed γ-ray numbers and spectra are consistent with those of terrestrial γ-ray flashes (TGFs) observed aboard spacecrafts. The RE flux is concentrated mainly within the domain of the Blue Jet fluorescence. This confirms that exactly the domain adjacent to a thundercloud is the source of the observed γ-ray flashes. The yield of photonuclear neutrons is calculated. One γ-ray pulse generates ∼10¹⁴–10¹⁵ neutrons. The possibility of the direct deposition of REs to the detector readings and the origin of the lightning-advanced TGFs are discussed. The text was submitted by the authors in English.     

Photonic flame effect

The results of study of the photonic flame effect observed in photonic crystals and nanocomposites based on opal matrixes are presented. The effect has been discovered recently [1] and manifests itself as radiation with duration of a few seconds in the blue-green spectral region under excitation by pulsed laser light with a wavelength of 694.3 nm and a pulse duration of 20 ns.     

Nitrogen-Doped Titanium Dioxide Thin Films Formation on the Surface of PLLA Electrospun Microfibers Scaffold by Reactive Magnetron Sputtering Method

Plasma Chemistry and Plasma Processing - Nitrogen-doped thin titanium dioxide films formed by the reactive magnetron sputtering method on the surface of PLLA electrospun microfibers scaffold were...     

Synthesis and Antibacterial Activity of New N9-Substituted Acridine-9-amines

Russian Journal of General Chemistry - A method for the synthesis of N9-substituted acridine-9-amines by reacting 9-chloroacridines with 2-(2-methyl-5- nitro-1H-imidazol-1-yl)ethanamine was...     

Structure of Water Microemulsion Particles: Study by Optical Methods

Physics of Wave Phenomena - It is shown by optical methods using light scattering intensity and shift of the stimulated low- frequency Raman scattering line that emulsion particles of the Emulson...     

Nanosized reactors based on polyethyleneimines: from microheterogeneous systems to immobilized catalysts

Effective nanoreactors based on polyethyleneimines (PEIs) for the hydrolytic cleavage of O-alkyl O-p-nitrophenyl chloromethylphosphonates (alkyl = ethyl, hexyl) and di(p-nitrophenyl)phosphate were developed in conformity with the idea of modeling the polyfunctional catalytic mechanism of enzymes. A step-by-step modification of the single PEI solution by additives with their own catalytic activities (sodium dodecyl sulfate and lanthanum salt) gave rise to a marked improvement in the reaction efficiency. A 104-106-fold acceleration of the reaction compared to the aqueous basic hydrolysis of the substrates was achieved in the sodium dodecyl sulfate-polyethyleneimine-La(III) ternary system. This system can be considered to be metallomicelles immobilized on a hydrophilic polymer matrix. When the PEI immobilized on silica gel was used as a catalyst, the full completion of the reaction was achieved for 100 min under mild conditions, while the half-life of the reaction in a comparable homogeneous regime exceeds 100 h.     

Reduction of elastic strains in directly-bonded silicon structures

The elastically strained state of the interface in directly-bonded silicon structures has been studied by x-ray diffraction topography and IR spectrometry. The pattern of the contrast observed in the x-ray topographs and the intensity oscillations in the IR spectra indicate a periodic strain distribution caused by the long-period surface microroughness on the plates to be bonded. The local microroughness did not exceed 2 Å, and it did not noticeably affect the interface structure. Two types of the structure were subjected to a comparative analysis, (i) with a smooth interface prepared by standard direct-bonding technology, and (ii) with an interface displaying a regular relief. The strain level in type-II structures was found to be lower by more than an order of magnitude. A model is proposed to account for the observed reduction of elastic strains at the bonded sections of the interface in terms of elastic relaxation of the free surfaces in the relief voids through their deflection and displacement.