Oligomerization of 1-Pentene on Zeolite Catalysts

Catalysis in Industry - The oligomerization of 1-pentene is an efficient process for producing environmentally friendly high-quality fuel components. The catalytic properties of FAU, OFF, MOR, BEA,...     

A novel semi-analytic method for the analysis of scattering by dielectric objects immersed in uniform media

The method for the solution of scattering problems with homogeneous dielectric scatterers based on a single coordinate multipole expansion, the Stratton-Chu integral and Maxwell's equations in the integral form is proposed in this paper. Its convergence is proved. The sources of ill-conditionality of constitutive algebraic systems are established. The method of their regularization based on the use of a scalar control parameter is suggested. For the sake of validation, the numerical analysis is performed for different testing objects.     

Study of the physical constants of a uranium graphite reactor lattice by means of a sub-critical assembly

It has been shown experimentally that it is possible to study-the physical constants of the uranium graphite reactor lattice by means of a subcritical assembly.The assembly consisted of a uranium graphite lattice of natural uranium rods for a mockup of the lattice of the Beloyarskii GRÉS type reactor. The subcritical assemblies were placed in the central part of a uranium graphite reactor using tubes of 2% enriched uranium rods. Experiments are described which showed that it is possible to measure the physical parameters of the reactor lattice, namely, the resonance escape probability ,the fast neutron multiplication , and the thermal utilization . Together with the assembly the reactor constituted a critical system. The sub-critical assembly was part of the lattice of the reactor under study. The results of the measurements given are in satisfactory agreement with the calculational data.The authors express their deep gratitude to one and all.The authors also tender thanks to A. V. Kamaev, M. E. Minashin, G. Ya. Rumyantsev, I. G. Morozov for their interest in the work, discussion of results, and valuable comments.     

Critical importance of the single-level approximation to account for the highly nonmonotonic dependences of carrier lifetimes on recombination impurity concentration

This paper is a continuation of an analysis regarding an increase in the lifetimes of nonequilibrium electrons π_n and holes πp by several orders of magnitude, observed with increasing concentration of recombination centers. It is shown that a substantial increase in πn and πp may also occur for three charge states of the recombination impurities N, and the curves πn=f(N) and π n=f(N) may each have two minima and maxima. Pis’ma Zh. Tekh. Fiz. 23, 39–45 (April 12, 1997)     

Boundary integrodifferential equations for electromagnetic scattering problems in three dimensions

On the basis of two vector representations of electromagnetic fields we introduce a new system of boundary integrodifferential equations for the solution of scattering problems in three dimensions. The unknowns of this system present two scalar functions, namely, the "" coefficients of Atkinson-Wilcox expansion; electromagnetic field being reconstructed with these functions by means of certain recursive-differential operators. We define an algebraic analog of the equations by expanding unknowns into Fourier series with respect to spherical harmonics. Verification of the approach is done on the basis of the solution of well-known canonical problems.     

Calculation of a two-phase flow in an axisymmetric nozzle

A system of differential equations is presented to describe a two-phase flow through an axisymmetric supersonic nozzle. The results for the solution of this system on a Minsk-14 computer are given. The theoretical results are compared qualitatively with the experimental data.