Konstantin Andreevich Lyakhov

The efficiency of a proton exchange membrane fuel cell (PEMFC) could be increased dramatically if a cheap way to enhance sluggish kinetics of oxygen reduction at the cathode surface would be found. In this paper, a mathematical model to describe control of PEMFC operation by the sequence of laser pulses of a specific temporal shape applied to electrode surface is proposed. An optimization problem to find an optimal sequence of laser pulses to control electrode activity is formulated.

Boron isotopes have many applications in industry: medicine, semiconductor, and solar energy. Especially massive demand is for boron-10 isotopes in nuclear industry for nuclear reactors shielding and control. Various aspects of laser-assisted boron isotope separation by retardation of condensation method, such as irradiation conditions and laser and vacuum system design, have been considered. Irradiation conditions include interaction scheme of laser radiation and supersonic beam, dependence of efficiency of excitation on gas flow temperature and pressure. Basic physical constraints on laser intensity and its spectral properties have been discussed. The relation of gas flow properties, nozzle design, and vacuuming rate has been elucidated as well.

A method for solving the problem of efficient population transfer from the ground to some excited state by available technical means (varying resonator length) is proposed. We consider a mixture of similar quantum systems distributed in a stationary gas flow in the resonator with variable resonator length, which implements tailored laser field close to the optimal one. In difference from previous works, in this work piezoelectric transducer (PZT; or actuator) is used as mean of control to manipulate variable resonator length. The external actions are optimized to selectively prepare different stationary states of different species which are then separated using their diffusion with rates which differ due to different masses. This system provides an example of the general problem of optimizing states of distributed systems with stationary gas flow with diffusion.

A new principal optical scheme for automatic recognition of the shape and relative position of inclusions in moving translucent objects is presented. A new criterion for automatic identification of structures (their localization) based on the analysis of the interference pattern projected on the surface of a CCD matrix, which is an element of the proposed scheme of an optical correlator based on the confocal laser tomograph, has been introduced. The results of this work may be of interest to the specialists in the field of non-destructive control; it can find application in the relevant fields

In this work, a method for solving the problem of efficient population transfer from the ground to some excited state by available technical means (varying resonator length) is proposed. We consider a mixture of similar quantum systems distributed in a stationary gas flow in the resonator with variable resonator length, which implements tailored laser field close to the optimal one. In difference from previous works, in this work piezoelectric transducer (PZT; or actuator) is used as mean of control to manipulate variable resonator length. The external actions are optimized to selectively prepare different stationary states of different species which are then separated using their diffusion with rates which differ due to different masses. This system provides an example of the general problem of optimizing states of distributed systems with stationary gas flow with diffusion.

The application of the method of laser-assisted retardation of condensation has been considered for molybdenum isotope separation. Enrichment factor as a function of pressure and temperature of gas flow cold-core have been evaluated. Since the maximal value of the enrichment factor is not high(~ 1.8), to achieve desired enrichment level in products an iterative procedure is applied. To reduce the amount of wastes and increase the performance of the SILARC method, two-stage countercurrent cascade is considered. Relations between the molar and isotopic fractions of target isotopologues on the first and second stages of the cascade at each iteration are found. The Optimization problem is formulated to evaluate optimal physical parameters of this cascade.

In this paper the enrichment factor and the product cut for molybdenum isotopes separation by the laser assisted retardation of condensation method are found. These quantities are evaluated for different gas flow temperatures and pressures. They are computed by solving a set of transport equations for molar fractions of four characteristic groups represented in the gas flow (i.e., monomers, dimers, excited monomers, and epithermals) in a static approximation on each iteration. The estimates for the stabilization rate of this distributed system with diffusion and nonlinear reaction term are performed. In order to find laser excitation rate, photo-absorption cross section as a function of the gas flow pressure and temperature is evaluated from the experimental data.

A new optimization criterion for iterative zirconium isotope recovery by laser-assisted retardation of condensation is introduced. Generally, the optimization should be performed over the following set of parameters: gas flow pressure and temperature, target gas molar fraction, laser pulse intensity, laser beam radius, nozzle throat height and width, total processing time (number of iterations), and irradiation cell length. The laser intensity variation range should satisfy the condition of applicability of the isotope separation method used, and temperature in the mixing tank should be high enough to prevent condensation of the target gas. The evolution of the objective function for zirconium isotope separation has been evaluated as a function of the gas flow core temperature at different ambient gas pressures.