Exchange Interaction of Electron and Positron Bunches
Exchange interaction of electron and positron bunches is simulated using the particle-in-cell method and macroscopic electron and positron wave functions. It is shown that a periodic exchange process with low or high nonlinearity is realized during variations in the electron and positron concentrations.
We analyze the role of local geometry in the spin and orbital interaction in transition metal compounds with orbital degeneracy. We stress that the tendency observed in the most studied case (transition metals in O6 octahedra with one common oxygen—common corner of neighboring octahedra—and with ~180° metal–oxygen–metal bonds), that ferro-orbital ordering renders antiferro-spin coupling and, vice versa, antiferro-orbitals give ferro-spin ordering, is not valid in the general case, in particular, for octahedra with a common edge and with ~90° M–O–M bonds. Special attention is paid to the “third case,” that of neighboring octahedra with a common face (three common oxygens), which has largely been disregarded until now, although there are many real systems with this geometry. Interestingly enough, the spin-orbit exchange in this case turns out to be simpler and more symmetric than in the first two cases. We also consider, which form the effective exchange takes for different geometries in the case of strong spin–orbit coupling.
The numerical simulation of nonlinear time-dependent processes of the resonant interaction condensations charges in electron-positron substance with the formation of quantum macroplasmoid in terms of classical large particles model and quantum macroscopic model of single-particle wave functions has been conducted. Unlike the point kinematic approach of quantum electrodynamics, the particles are treated as deformable clots charge.
Electron-positron medium is considered as a promising implementation of powerful microwave devices on multibeam electron and positron streams. Simulation of the resonant interaction processes in electron-positron substance is carried out using macroscopic wave functions of electrons and positrons of macroscopic quantum theory. It is shown that at optimum space charge observed nonlinear resonance exchange process leading to the compensation of the Coulomb field.
The physical-mathematical model of the sensors block of space radiation fluxes parameters monitoring module has been developed. The simulation of the sensors block output has been carried out using the series of the spectra representing space radiation spectra at different spaceship orbits in different phases of the solar activity cycle. The optimisation of the sensors block of space radiation fluxes parameters monitoring module has been carried out based on the simulation results.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.