Search academic texts

Information × Registration Number 0211U009125, 0109U006505 , R & D reports Title Kinetic aspects of nanoparticles ensembles formation during pyrolysis of solution drops at reduced pressure popup.stage_title Head Slezov Vitaly, Registration Date 30-06-2011 Organization Institute for Theoretical Physics of National Science Center "Kharkov Institute of Physics and Technology" popup.description2 A process of nanoparticles formation, taking place in aerosol reactor at reduced pressure during the pyrolysis of drops of nanoparticle substance solution, was investigated theoretically. For the description of nucleation and growth of nanoparticles in limited volume at changing parameters a mathematical model of cluster thermodynamics, based on the generalized Gibbs approach, was developed. It was shown that within the framework of this approach a concept of critical cluster can be generalized also for an unstable initial state. The role of finite system size in the process of cluster formation was analyzed. The general conclusion was made, that the degree of the system stability with respect to phase transformation is increased with a diminution of the system size at the expense of exhaustion effects. The thermodynamic analysis was used as a basis for the description of the kinetics of phase transition. The proposed approach allowed to describe transition from an unstable state of a system to metastable one and finaly through a ripening stage to the equilibrium state. It was shown, that a characteristic ripening time and time of the phase transition decrease with the width of initial clusters size distribution. By a numerical solution of differential-difference Becker-Doering equations an evolution of a metastable system with nucleation and growth of new phase nanoparticles in a limited volume was simulated. It was shown, that there is a possibility of determination of a character of the initial size distribution function of new phase particles by the form of the distribution function at intermediate stages of the phase transformation process. Product Description popup.authors Абизов Олександр Сергійович Давидов Леонід Миколайович Сльозов Віталій Валентинович Шаповалов Роман Володимирович popup.nrat_date 2020-04-02 Close