502 research outputs found
Synthesis of Meso‐Substituted Subphthalocyanine–Subporphyrin Hybrids: Boron Subtribenzodiazaporphyrins
The first syntheses of hybrid structures that lie between SubPhthalocyanines and SubPorphyrins are reported. The versatile, single-step synthetic protocol uses a preformed aminoisoindolene to provide the bridging methine unit and its substituent, while trialkoxyborates simultaneously act as Lewis acid/template and provider of the apical substituent. Selection of each component therefore allows controlled formation of diverse, differentially functionalised systems. The new hybrids are isolated as robust, pure materials that display intense absorption and emission in the mid-visible region. They are further characterised in solution and solid state by variable temperature NMR spectroscopy and X-ray crystallography respectivel
Weak Interaction Contributions in Light Muonic Atoms
Weak interaction contributions to hyperfine splitting and Lamb shift in light
electronic and muonic atoms are calculated. We notice that correction to
hyperfine splitting turns into zero for deuterium. Weak correction to the Lamb
shift in hydrogen is additionally suppressed in comparison with other cases by
a small factor .Comment: Minor editorial corrections, reference added, version to be published
in Phys. Rev.
Trapping with biased diffusion species
We analyze a trapping reaction with a single penetrable trap, in a one
dimensional lattice, where both species (particles and trap) are mobile and
have a drift velocity. We obtain the density as seen from a reference system
attached to the trap and from the laboratory frame. In addition we study the
nearest neighbor distance to the trap. We exploit a stochastic model previously
developed, and compare the results with numerical simulations, resulting in an
excellent agreement.Comment: 6 pages, 7 Postscript figure
The mathematical modelling of liner movement in a magnetic compressor: elastic, liquid and plastic liner models comparison
The paper is aimed to model the electromagnetic acceleration and braking of the liner in magnetic compressor. The 2D approach corresponding to the longitudinal section of spatial region is considered. Liquid, elastic, and plastic models of the liner are presented. The comparative analysis of calculation results for different models and their correlation with experimental data are carried out. The research of the influence of circuit parameters on liner braking is done
Mathematical modeling of gas flow in plasma torch vortex chamber
Mathematical model of moving gas in vortex chamber (inter-electrode gas supply insert) of plasma torch channel was developed. Effect of moving electric arc on the motion of gas is considered. Software for solving problems of three dimensional non-ideal gas dynamics in complex areas was developed.Побудовано математичну модель руху газу у форсунці (міжелектродній вставці) і в області анода каналу плазматрона. Модель враховує вплив електричної дуги на течію газу. Розроблено програмний комплекс для рішення завдань тривимірної неідеальної газової динаміки в областях складної геометричної форми.Построена математическая модель движения газа в форсунке (межэлектродной вставке) и в области анода канала плазматрона. Модель учитывает влияние электрической дуги на течение газа. Разработан программный комплекс для решения задач трехмерной неидеальной газовой динамики в областях сложной геометрической формы
Nonlinear monotonization of the Babenko scheme for the quasi‐linear advection equation
The paper is devoted to construction and development of new method for numerical solution of hyperbolic type equations [14, 17].
In the previous papers [4, 5, 6, 7, 8, 9] authors have investigated theoretically and tested experimentally 26 different finite‐difference schemes on 4 point patterns for the simplest hyperbolic equation: linear advection equation. This equation has the main features of every hyperbolic equation and is the important part of many mathematical models. In other cases the advection operator is the important part of the full operator of the problem. All 26 schemes have been compared experimentally on the special representative set of tests. Nevertheless to simplicity of the equation, almost all schemes have different disadvantages. They are discussed in detail in the cited papers. So, the investigation of new schemes for this equation is still an important task.
In [4, 5, 6, 7, 8, 9] some new schemes were constructed for solving this advection equation. The nonlinear monotone Babenko scheme ("square") proved to be the best among all 26 schemes. So, it is a big interest to generalize this scheme to more difficult equations. The important example is a quasi‐linear advection equation.
In this paper our basic aim is to construct a quasi‐monotone nonlinear Babenko scheme for solving the quasi‐linear advection equation and to test it experimentally. The monotonisation of the scheme is done by adding the artificial diffusion with limiters. We also present advanced results of comparative analysis of the new scheme with other known schemes. We have considered explicit and implicit upwind approximation schemes [4, 6, 13, 16] which is firstorder accurate in time and space, the Lax‐Wendroff scheme [4] which is the first order accurate in time and second order accurate in space. We also analyze the monotonised “Cabaret” scheme proposed in [10, 11]. It is second order accurate in time and space, and its monotonisation is based on apriori knowledge of the dependence region of the exact solution. The authors of this scheme called it by “jumping advection”. The considered schemes are compared numerically by using a set of tests, which is similar to one used in [4, 5, 6, 8].
Šiame straipsnyje pasiūlyta kvazi‐monotonie netiesine Babenkos skirtumu schema kvazitiesinei pernešimo lygčiai spresti. Schemos monotoniškumas pasiekiamas pridedant dirbtine difuzija su apribojimais. Pateiktas šios schemos palyginimas su kitomis schemomis. Taip pat analizuojama antros eiles pagal laika ir erdve monotonine “Cabaret” schema. Pateikti testu rezultatai.
First Published Online: 14 Oct 201
Changes in the species composition and abundance of young-of-the-year fishes in the upper Volga stretch of the Kuibyshev Reservoir during the period of 1991 to 2009
© 2014, Pleiades Publishing, Ltd. The species composition and abundance of young-of-the-year fishes have been analyzed in catches made in the upper Volga stretch of the Kuibyshev Reservoir between 1991 and 2009. It has been found that the juvenile abundance of roach and blue bream has decreased, while that of perch, silver bream, and spined loach has increased, with young-of-the-year juveniles of common rudd, tubenose goby, round goby, and black-striped pipefish appearing in catches. The results of the study show that, against the background of juvenile population decline in many spring-spawning fish species, the abundance and species diversity of young of the year in summer-spawning species has increased during the observation period
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