β-Keto phosphonic and phosphinic esters - Communication 6. Products of the reaction of chloro- and bromo-acetone with diethyl ethylphosphonite and with sodium ethyl ethylphosphonite

1. The action of diethyl ethylphosphonite on chloroacetone results in the formation of ethyl isopropenyl ethylphosphonate. In the case of bromoacetone, as well as ethyl isopropenyl ethylphosphonate, ethyl acetonylethylphosphinate is formed. 2. The reaction of chloroacetone with sodium ethyl ethylphosphonite gives ethyl (1,2-epoxy-1-methylethyl)ethylphosphinate. 3. A study was made of the Raman spectra and ultraviolet absorption spectra of previously undescribed compounds. © 1961 Consultants Bureau

Esters of β -ketophosphonic acids. VII. The products of the reaction of α-chlorocyclohexanone with the diethyl ester of ethylphosphonous acid and the sodium salt of the monoethyl ester of ethylphosphonous acid

The action of diethyl ethylphosphonite on α-chlorocyclohexanone gives cyclohexen-1-yl-1 -ethyl ethylphosphonate, Cyclohenen-1-yl-1-ethyl ethylphosphonate is also obtained by the action of sodium monoethyl ethylphosphonite on a-chlorocyclohexanone. © 1961 Consultants Bureau

Time-dependent density functional theory study of the luminescence of 2-aminopyrimidine derivative

The research was supported by Russian Foundation for Basic Research and the government of the Novosibirsk region of the Russian Federation, grant № 18–43–540016 r_a

Optical echo in photonic crystals

The dynamics of photonic wavepacket in the effective oscillator potential is studied. The oscillator potential is constructed on a base of one dimensional photonic crystal with a period of unit cell adiabatically varied in space. The structure has a locally equidistant discrete spectrum. This leads to an echo effect, i.e. the periodical reconstruction of the packet shape. The effect can be observed in a nonlinear response of the system. Numerical estimations for porous-silicon based structures are presented for femtosecond Ti:Sapphire laser pump.Comment: 4 page

Nonlinear acoustic waves in channels with variable cross sections

The point symmetry group is studied for the generalized Webster-type equation describing non-linear acoustic waves in lossy channels with variable cross sections. It is shown that, for certain types of cross section profiles, the admitted symmetry group is extended and the invariant solutions corresponding to these profiles are obtained. Approximate analytic solutions to the generalized Webster equation are derived for channels with smoothly varying cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic corrections introduced mainly in the Introduction and References. Several typos were also correcte

On discretization in time in simulations of particulate flows

We propose a time discretization scheme for a class of ordinary differential equations arising in simulations of fluid/particle flows. The scheme is intended to work robustly in the lubrication regime when the distance between two particles immersed in the fluid or between a particle and the wall tends to zero. The idea consists in introducing a small threshold for the particle-wall distance below which the real trajectory of the particle is replaced by an approximated one where the distance is kept equal to the threshold value. The error of this approximation is estimated both theoretically and by numerical experiments. Our time marching scheme can be easily incorporated into a full simulation method where the velocity of the fluid is obtained by a numerical solution to Stokes or Navier-Stokes equations. We also provide a derivation of the asymptotic expansion for the lubrication force (used in our numerical experiments) acting on a disk immersed in a Newtonian fluid and approaching the wall. The method of this derivation is new and can be easily adapted to other cases

Quaternionic factorization of the Schroedinger operator and its applications to some first order systems of mathematical physics

We consider the following first order systems of mathematical physics. 1.The Dirac equation with scalar potential. 2.The Dirac equation with electric potential. 3.The Dirac equation with pseudoscalar potential. 4.The system describing non-linear force free magnetic fields or Beltrami fields with nonconstant proportionality factor. 5.The Maxwell equations for slowly changing media. 6.The static Maxwell system. We show that all this variety of first order systems reduces to a single quaternionic equation the analysis of which in its turn reduces to the solution of a Schroedinger equation with biquaternionic potential. In some important situations the biquaternionic potential can be diagonalized and converted into scalar potentials

Silver(I) coordination compounds with polydentate pyrimidine ligands: thermochromism of luminescence

The main goal of this work is to study how the substituent in position 2 of the pyrimidine ring affects both luminescent properties and structures of silver(I) complexes. A series of coordination compounds, [AgL1NO3], [AgL1X]n, [Ag2(L2)2X2] (X = I, Br, Cl–), [AgL1(PPh3)Y] (Y = CF3SO3, BF4, NO3), [AgL3NO3·CH3CN]n, have been synthesized and structurally characterized. According to the X-ray single data, the complexes [AgL1NO3], [AgL1(PPh3)Y] adopt mononuclear structures; the complexes [Ag2(L2)2X2] are binuclear; [AgL1X]n and [AgL3NO3·CH3CN]n are polymeric compounds.The research was supported by the President of the Russian Federation Grant for young scientists МК-1219.2020.3; by Russian Foundation for Basic Research and the government of the Novosibirsk region of the Russian Federation, grant № 18–43–540016 r_a

Temperature and excitation wavelength dependent emission of silver(I) complexes with an aminopyrimidine ligand

The research was supported by the President of the Russian Federation Grant for young scientists МК-1219.2020.3; by Russian Foundation for Basic Research and the government of the Novosibirsk region of the Russian Federation, grant № 18–43–540016 r_a

Особенности процедуры детерминизации конечных автоматов

The theory of formal languages widely uses finite state automata both in implementation of automata-based approach to programming, and in synthesis of logical control algorithms.To ensure unambiguous operation of the algorithms, the synthesized finite state automata must be deterministic. Within the approach to the synthesis of the mobile robot controls, for example, based on the theory of formal languages, there are problems concerning the construction of various finite automata, but such finite automata, as a rule, will not be deterministic. The algorithm of determinization can be applied to the finite automata, as specified, in various ways. The basic ideas of the algorithm of determinization can be most simply explained using the representations of a finite automaton in the form of a weighted directed graph.The paper deals with finite automata represented as weighted directed graphs, and discusses in detail the procedure for determining the finite automata represented in this way. Gives a detailed description of the algorithm for determining finite automata. A large number of examples illustrate a capability of the determinization algorithm.Конечные автоматы широко используются в теории формальных языков, при реализации автоматного подхода к программированию, а также при синтезе алгоритмов логического управления. Для обеспечения однозначности работы алгоритмов синтезированные конечные автоматы должны быть детерминированными. В рамках подхода к синтезу управлений мобильными роботами, например, основанному на применении теории формальных языков, возникают задачи построения различных конечных автоматов, однако такие конечные автоматы, как правило, не будут детерминированными. Алгоритм детерминизации может быть применен к конечным автоматам, заданным различными способами. Наиболее просто основные идеи алгоритма детерминизации можно объяснить, используя представления конечного автомата в виде взвешенного ориентированного графа.В работе рассматриваются конечные автоматы, представленные как взвешенные ориентированные графы, и подробно разбирается процедура детерминизации конечных автоматов, представленных указанным образом. Приведено подробное изложение алгоритма детерминизации конечных автоматов. Работа алгоритма детерминизации проиллюстрирована большим количеством примеров