Акустооптические ячейки c пьезопреобразователями клиновидной формы, возбуждаемыми на высоких гармониках
Light diffraction in a nonuniform acoustic field induced by a wedge shaped piezoelectric trans ducer is theoretically studied. Electric, acoustic, and acoustooptic characteristics of cells with such transducers are calculated. The emphasis is on the features of cell operation in the case when a piezoelectric plate is excited at the third harmonic. The acoustic field is shown to possess a complex amplitude and phase structure varying with the ultrasound frequency. The efficiency of acoustooptic diffraction depending on the acoustic wave amplitude and phase mismatch is studied. It is established that the efficiency of the Bragg diffraction can approach 100% despite a noticeable phase mismatch. Optimal values for the ultrasound power and angles of light incidence onan acoustooptic cell are found.
Diffraction of light in a non-homogeneous acoustic field produced by a wedge-shaped piezoelectric transducer is studied theoretically. Electrical, acoustic and acousto-optic characteristics of cells with the wedge-shaped transducers are calculated. Most attention is focused on special features of these cells operation at transducer’s third harmonic frequency. It is shown that the acoustic field has a complicated amplitude and phase structure which varies with ultrasound frequency. The dependence of the acousto-optic diffraction efficiency on the acoustic wave amplitude and the phase mismatch is studied. It is established that the diffraction efficiency can approach 100% despite a noticeable phase mismatch. Optimal values of acoustic power and light incidence angles are found. It is revealed that due to the wedge-like form of the transducer the frequency band at the third harmonic can be several times increased with retaining a high value of the electric-to-acoustic power conversion.
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.