Kinetics of Binary Nucleation of Vapors in Size and Composition Space

We reformulate the kinetic description of binary nucleation in the gas phase using two natural independent variables: the total number of molecules g and the molar composition x of the cluster. The resulting kinetic equation can be viewed as a two-dimensional Fokker-Planck equation describing the simultaneous Brownian motion of the clusters in size and composition space. Explicit expressions for the Brownian diffusion coefficients in cluster size and composition space are obtained. For characterization of binary nucleation in gases three criteria are established. These criteria establish the relative importance of the rate processes in cluster size and composition space for different gas phase conditions and types of liquid mixtures. The equilibrium distribution function of the clusters is determined in terms of the variables g and x. We obtain an approximate analytical solution for the steady-state binary nucleation rate that has the correct limit in the transition to unary nucleation. To further illustrate our description, the nonequilibrium steady-state cluster concentrations are found by numerically solving the reformulated kinetic equation. For the reformulated transient problem, the relaxation or induction time for binary nucleation was calculated using Galerkin\u27s method. This relaxation time is affected by processes in both size and composition space, but the contributions from each process can be separated only approximately

The role of Russia in the world education market

This article considers the features of the education market formation. It is shown that the undoubted leaders by number of foreigners involved in educational projects are Western European countries (Germany, France, Great Britain) and North American countries (USA and Canada).  Currently, the world education market reflects the patterns of interaction between producers, providers and users of educational services. The current education system is aimed at meeting the demand of foreign citizens on educational services through the use of a whole set of technologies related to improving skills and competitiveness of labor market specialists. It is proved that the leading market is associated with attracting foreign students to obtain higher education in Russia. In this article the main trends in the development of Russian education system were analyzed and results of the "Export of Education" program were described

Formation of motivation to learn the vocation-related language

The current situation on the global education market bears the need for new approaches to learning Russian as a foreign language. The innovation concerns both professors and students’ activity. The success in comprehension of scientific language is largely dependent on students’ motivation to study the vocation-related language. The article covers the methodological basis of the approach which may improve preparatory department students’ motivation to study

Kinetics of ion-induced nucleation in a vapor-gas mixture

A general solution for the steady-state ion-induced nucleation kinetics has been derived, considering the differences between ion-induced nucleation and homogeneous nucleation. This solution includes a new effect for nucleation kinetics, the interaction of charged clusters with vapor molecules. Analytical expressions for the ion-induced nucleation rate have been obtained for the limiting cases of high and low thermodynamic barriers. The physical explanation of the so-called sign effect is proposed based on multipole expansion of an electric field of the cluster ion. This theory gives good agreement with experiments and is used to elucidate experimentally observed phenomena

Nucleation and growth of gold nanoparticles initiated by nanosecond and femtosecond laser irradiation of aqueous [AuCl4]-

Irradiation of aqueous [AuCl4]with 532 nm nanosecond (ns) laser pulses produces monodisperse (PDI = 0.04) 5 nm Au nanoparticles (AuNPs) without any additives or capping agents via a plasmon- enhanced photothermal autocatalytic mechanism. Compared with 800 nm femtosecond (fs) laser pulses, the AuNP growth kinetics under ns laser irradiation follow the same autocatalytic rate law, but with a significantly lower sensitivity to laser pulse energy. The results are explained using a simple model for simulating heat transfer in liquid water and at the interface with AuNPs. While the extent of water superheating with the ns laser is smaller compared to the fs laser, its significantly longer duration can provide sufficient energy to dissociate a small fraction of the [AuCl4]present, resulting in the formation of AuNPs by coalescence of the resulting Au atoms. Irradiation of initially formed AuNPs at 532 nm results in plasmon-enhanced superheating of water, which greatly accelerates the rate of thermal dissociation of [AuCl4]and accounts for the observed autocatalytic kinetics. The plasmon-enhanced heating under ns laser irradiation fragments the AuNPs and results in nearly uniform 5 nm particles, while the lack of particles’ heating under fs laser irradiation results in the growth of the particles as large as 40 nm

Experience in the surgical management of children with complicated crohn's disease

Objective: To present experience in pre-surgical diagnosis, selection of surgical tactics and volume of intervention in different variants of gastrointestinal tract lesions and disease activity. Materials and methods: We undertook cross-sectional, retrospective-prospective study of 64 children who underwent surgery due to complicated CD. We analyzed CD activity via PCDAI, medications used, inflammation localization, and changes in mass-growth parameters at pre-surgery stage. Results: Three patients from the group of 44 children with two-stage surgical treatment later showed inefficacy of GEBD in post-operative period. The disease progression was revealed and, therefore, subtotal colectomy was required. Three children had secondary adhesion of surgical wounds by means of active immunosuppressive therapy at preoperative period, and five patients developed suture sinuses at post-operative period. Early adhesive intestinal obstruction was revealed in 3 (4.7%) cases, and they required re-surgery. Conclusions: Personalized approach to the surgical treatment of children with complicated CD has shown its efficacy due to the small percentage of postoperative complications with re-surgery. There was significant improvement in mass-growth parameters, recovery of albumin levels, and anemia decrease in 96.9% of cases in the long-term postoperative period (6 months or more)