Synthesis and biological properties of novel structural analogs of isothiobarbamine

Russian Chemical Bulletin - Novel structural analogs of isothiobarbamine, which differ from the prototype scaffold by the substituent at position 2 of the pyrimidine heterocycle, were for the first...     

Electrochemical and Transport Characteristics of Membrane Systems in the Electronanofiltration Separation of Solutions Containing Ammonium Nitrate and Potassium Sulfate

Russian Journal of Electrochemistry - Electrochemical and transport characteristics of systems equipped with OPMN-P and OFAM-K membranes during operation in electronanofiltration cell are studied...     

Conformal Contractions and Lower Bounds on the Density of Harmonic Measure

We give a concrete sufficient condition for a simply-connected domain to be the image of the unit disk under a nonexpansive conformal map. This class of domains is also characterized by having sufficiently dense harmonic measure. The relation with the harmonic measure provides a natural higher-dimensional analogue of this problem, which is also addressed.     

Adjoint problems of mechanics of continuous media in gas‐laser cutting of metals

A mathematical model of gaslaser cutting of metal plates in an inert gas is proposed. The formation and flow of the liquid metal melt film at the cutting front is considered within the framework of incompressible boundarylayer equations. Based on the resultant analytical solution, a local law of energy conservation on the cutting surface is derived, which takes into account the meltfilm thickness and the temperature dependence of thermophysical parameters of the metal. The problem of the cutting shape and depth is solved in the twodimensional formulation. A comparison with experimental data is made in terms of the cutting depth and maximum cutting velocity for carbon and alloy steel.     

Formulas for the heat and diffusion fluxes to a catalytic surface in a chemically nonequilibrium multicomponent boundary layer

On the basis of an asymptotic expansion of the solution of the equations of a multicomponent chemically nonequilibrium boundary layer for large Schmidt numbers, formulas are obtained for the heat flux and the diffusion fluxes of the reaction products and chemical elements on a surface with arbitrary catalytic activity. The results are compared with well-known analytic and numerical solutions. The comparison reveals the high accuracy of the formulas proposed. The results of calculating the diffusional separation of the mixture due to the selectivity of the catalytic properties of the surface with respect to recombination of oxygen and nitrogen atoms are presented. Values of the reduction of the convective heat fluxes due to the catalytic properties of the surface are obtained over a wide range of conditions in the free stream.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 171–176, March–April, 1996.     

Subsonic axisymmetric wake in a viscous gas

The problem of the subsonic axisymmetric flow of a compressible viscous perfect gas in the wake behind a cylindrical body with a flat base section is considered under the condition that the stream parameters are given at infinity and at some distance x_w upstream of the base section. (Let us note that the possibility of the existence of an axisymmetric wake at moderate Reynolds numbers has been shown experimentally [1].) The problem is solved by the numerical build-up method in a cylindrical x, y coordinate system on the basis of the Navier-Stokes equations, by a method elucidated in [2, 3]. Equations obtained from the fundamental system by a passage to the limit while taking into account the symmetry conditions on the axis y=0 are used on the axis of symmetry.     

Synthesis, crystal structure, and luminescent properties of a silver(I) perrhenate complex with phenazine

The silver complex with phenazine [Ag(Phz)₂(H₂O)]ReO₄ (Phz is C₁₂H₈N₂) has been synthesized, and its crystal structure has been determined. The crystals are triclinic: space group $P\bar 1$ , a = 9.587(1) Å, b = 10.875(1) Å, c = 11.668(1) Å, α = 104.98(1)°, β = 103.87(1)°, γ = 92.94(1)°, V = 1132.6(2) ų, Z = 2, ρ_calc = 2.160 g/cm³. The structure is composed of the [Ag(Phz)₂(H₂O)]⁺ silver cationic complexes and ReO ₄ ^? anions. The Ag⁺ ion is coordinated by two nitrogen atoms of independent phenazine molecules and the water oxygen atoms and has a T-shaped coordination (Ag-N_av 2.223 Å, Ag-O_w 2.498(8) Å). Phenazine, being an electron-donor ligand, forms columns due to π-π stacking interaction between the aromatic groups. The water molecules form hydrogen bonds with the oxygen atoms of water molecules of neighboring complexes and with oxygen atoms of the ReO ₄ ^? anions.     

Scanning a Silicon Photomultiplier with a Laser Beam

Physics of Particles and Nuclei Letters - The Silicon Photomultiplier (SiPM) is a novel semiconducting photodetector which can detect single photons. It consists of many microcells (pixels)...     

Homocondensation of 1,3-di(5-acenaphthenyl)but-2-ene-1-one

Russian Chemical Bulletin - Homocondensation of 1,3-di(5-acenaphthenyl)but-2-en-1-one obtained by dimerization of 5-acetylacenaphthene leads to 1,3,5-tri(5-acenaphthenyl)benzene. No alternative...