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The interaction of electromagnetic waves with a spherical metallic nanoparticle is studied in this work. Within the model of an infinite spherical potential well, taking into account the size dependence of the Fermi energy, a formula for the dielectric tensor is obtained and its diagonal components are calculated. The calculation results demonstrate a strong size and frequency dependencies of the real and imaginary parts of the dielectric function. Calculations were performed for Ag, Cu, and Al particles.

Formulas of efficient relaxation time are obtained for the cases when the free length of electrons is less or comparable with the characteristic dimensions of metallic regions. The frequency dispersion of optical characteristics of spherical bimetallic particles is calculated near plasma resonance in the absence of quantum-size effects. Retaining the style of common description of metallic particles based on the Mie–Drude theories, the frequency dependence of electric dipole polarizability of a two-layered metallic nanosphere was analyzed. The appearance of two polarizability maxima is the result of a difference in core and shell metals. The calculations are conducted for the following particles immersed into teflon: Au@Ag, Ag@Au, Au@Pt, Pt@Au, and Pt@Pd. It is demonstrated that the optical characteristics of bimetallic particles can be controlled by means of changing their composition and volumetric metal content. Cross-sections of absorption and scattering, as well as optical radiation efficiency of the particles in a wide spectrum range are calculated. Possible temperature of bimetallic particles at the absorption of an electromagnetic wave (for the photothermal therapy of malignant tumors) is estimated.

Optical properties of core–shell (metal) nanoparticles and composites based on them were investigated in the classical approximation. Frequency dependences of the real and imaginary parts of the dielectric permittivity of bilayer particles and absorption coefficients of composites based on them were calculated. Small-scale oscillations of the real and imaginary parts of the dielectric permittivity and absorption coefficient were found in the low-frequency spectral region. The behavior of the dielectric permittivity of bilayer nanoparticles was analyzed for the limiting cases of thin and thick shells. The influence of the effective mean free pathlength of electrons on the optical characteristics of the bilayer nanoparticles was considered. Two maxima of the composite absorption coefficient were demonstrated to be due to hybridization of polar modes.

The optical properties of an ensemble of metal nanoparticles coated with an oxide layer have been investigated within framework of the classical theory. The influence of the electron-scattering mechanisms on the polarizability of nanoparticles is analyzed. The limiting case of a thin oxide layer is considered, and analytical expressions for the real and imaginary parts of the polarizability are derived. The evolution of the frequency dependences of the polarizability and extinction coefficient upon variation in the particle size and oxide-layer thickness is investigated. It is shown that the consideration of the size dependence of the surface component of the relaxation time changes the character of the size dependence of the frequency of surface plasmons of two-layer nanoparticles.

The absorption of electromagnetic radiation by a composite based on bimetallic nanoparticles with a “core–shell” type of structure has been analyzed using the Maxwell–Garnett theory. Expressions have been obtained for the real and imaginary parts of the dielectric function of a two-layered particle in the limiting cases of “thick” and “thin” shells. It has been established that the presence of two metals in the composition of the inclusions leads to a splitting of the maxima and minima in the frequency dependences of the dielectric function and of the coefficient of absorption of the nanocomposite. The frequency dependences of the real and imaginary parts of the dielectric function and of the coefficient of absorption of the composite with bimetallic nanoparticles of different metals have been calculated. An essential influence of both the geometric characteristics of the particles-inclusions and of their composition on the optical properties of the composite has been revealed.

The optical properties of spherical metal–oxide nanoparticles were studied in the framework of the Drude theory. Frequency dependences of the real and imaginary parts of the dielectric constant, coherence loss parameter, and absorption coefficient of bilayer Ag, Al, and Cu nanoparticles of radii 10–30 nm in various matrices were calculated. The behavior of the frequency dependences of the imaginary part of the dielectric constant and absorption coefficient at low frequencies was determined by the contribution of electron surface-scattering mechanisms.

The influence of the cross-section geometry of metal nanowires on the dielectric tensor has been examined. Diagonal and off-diagonal components of the dielectric tensor were calculated taking the size dependence of the Fermi energy into account within the free-electron model using the boundary-shape perturbation method. The effect of variation of the eccentricity of the cross section, the effective radius, and the composition of nanowires on frequency dependences of the real and imaginary parts of components of the dielectric tensor was studied. Calculations were performed for Ag, Cu, and Al.

Frequency dependences have been obtained for the real and imaginary parts and the absolute values of the components of the polarizability tensor of metal-oxide nanowires, as well as for the absorption and scattering cross-sections. The limiting cases of the ‘thick ” and “thin ” outer oxide layers are studied. Numerical calculations are performed for Al, Cu, and Ag wires coated with a corresponding oxide layer. The models where the dielectric constant of an oxide is either a constant or a function of the frequency are considered. In the last case, experimental frequency dependences of the refractive and extinction indices are used. The influence of the oxide layer thickness on the frequency dependences of the polarizability and the absorption and scattering cross-sections is analyzed. It is found that the presence of an oxide leads to a decrease in the frequency of surface plasmons in two-layer nanowires due to the influence of classical size effects., В роботi одержано спiввiдношення для частотних залежностей дiйсної й уявної частин та модуля компонентiв тензора поляризовностi, а також перерiзiв поглинання i розсiювання метал-оксидних нанодротiв. Дослiджено граничнi випадки “товстого” I “тонкого” зовнiшнього шару оксиду. Чисельнi розрахунки проведено для дротiв Al, Cu i Ag, вкритих шаром власного оксиду. Розглянуто випадки, коли дiелектрична проникнiсть оксиду є постiйною величиною або є функцiєю частоти. В останньому випадку для визначення цiєї залежностi було використано апроксимацiю експериментальних кривих частотних залежностей показникiв заломлення та екстинкцiї. Проаналiзовано вплив змiни товщини оксидного шару на поведiнку частотних залежностей поляризовностi i перерiзiв поглинання i розсiювання. Встановлено, що наявнiсть оксиду приводить до зменшення частоти поверхневих плазмонiв у двошарових нанодротах внаслiдок впливу класичних розмiрних ефектiв.

Проаналізовано можливість використання розігріву біологічних тканин при збудженні поверхневих плазмонів у двошарових сферичних метал-графенових наночастинках для термодеструкції злоякісних новоутворень. Для визначення частотних залежностей діелектричної функції металевого ядра і провідності графенової оболонки використано моделі Друде і Кубо, відповідно, а розподіли температури в тканинах пухлини та оточуючих її здорових тканинах визначаються розв’язками неоднорідних рівнянь теплопровідності. Для чисельних оцінок і розрахунків використано відомі з літератури значення теплофізичних параметрів тканин пухлини і здорових тканин людини. Досліджено еволюцію частотних залежностей поляризовності і перерізів поглинання вказаних наночастинок при зміні радіусу і матеріалу металевого ядра і товщини графенової оболонки. Показано, що зі збільшенням радіусу металевого ядра або товщини графенової оболонки відбувається зростання максимальних значень уявної частини поляризовності і перерізу поглинання, що пов’язано з підсиленням взаємодії з електромагнітною хвилею зі збільшенням об’ємного вмісту металу у композитній наночастинці і високою концентрацією вільних електронів у графенових шарах. Продемонстровано можливість спектральних зсувів максимумів поляризовності і перерізу поглинання при зміні матеріалу ядра двошарової наночастинки внаслідок суттєвої різниці у значеннях частот об’ємних плазмонів і внеску іонного остову в діелектричну функцію. Встановлено, що теплопровідність в задачі про нагрівання біологічних тканин при збудженні поверхневого плазмонного резонансу у композитній наночастинці є квазістаціонарною. Доведено, що даний метод терапії раку є нешкідливим для здорових тканин, що оточують пухлину, внаслідок їх вкрай незначного нагрівання. Результати чисельного моделювання свідчать про необхідність застосування конгломерату метал-графенових наночастинок з метою підвищення ефективності терапії. The possibility of using heating of body tissue upon excitation of surface plasmons in two-layer spherical metal-graphene nanoparticles for thermal destruction of malignant neoplasms has been analyzed. Drude and Kubo models have been used to determine the frequency dependences of the dielectric function of the metal core and the conductivity of the graphene shell, respectively, and the distributions of temperatures in tumor tissue and surrounding healthy tissue have been determined by solutions of nonhomogeneous thermal conductivity equations. Values of thermophysical parameters of tumor tissue and healthy human tissue known from the literature have been used for numerical estimates and calculations. The evolution of the frequency dependences of the polarizability and absorption cross-sections of the indicated nanoparticles with the variation of the radius and material of the metal core and the thickness of the graphene shell has been studied. It has been shown that an increase in the radius of the metal core or thickness of the graphene shell results in an increase in the maximum values of the imaginary part of the polarizability and absorption cross-section, which is associated with increased interaction with the electromagnetic wave with increasing bulk metal content in the composite nanoparticle and with high concentration of free electrons in graphene layers. The possibility of spectral shifts of the polarizability maxima and the absorption cross-section with the variation of the core material of a two-layer nanoparticle, due to the essential difference in the values of the frequencies of bulk plasmons and the contribution of the ion core to the dielectric function, has been demonstrated. It has been established that the thermal conductivity is quasi-steady in the problem of heating of body tissue upon excitation of surface plasmon resonance in a composite nanoparticle. It has been proved that this method of cancer therapy is harmless to healthy tissue surrounding the tumor due to their extremely low heat. The results of numerical modeling demonstrate the need to use a conglomerate of metal-graphene nanoparticles in order to increase the effectiveness of therapy.

In this work, the database was designed and implemented in accordance with the requirements of the relational model, which ensures the storage and collective access to the information of the auto-filling system and CMS WordPress data. Algorithms of system functioning were developed, the order of interaction of classes during program code execution was determined, as a result of which the application was implemented. Template Method architectural pattern was chosen to implement the web-based automatic content filling system. The following tools and technologies were selected to create the software package HTML markup language for HTML documents; programming language PHP; MySQL database management environment; Apache web server; the OpenServer package. The algorithms of the basic processes of content filling automation were considered and the interaction of the system classes during the processes of parsing, filtering and storing of information were analyzed. The developed system does not require specialized hardware, additional settings and deployment tools other than the standard ones for such plugins. This application is mostly for the site administrator and does not have user interface. That is why the features of the plugin automation system configuration interface; RSS feeds view and management interface, as well as the RSS feed configuration interface are described in detail. In the future, this system can be improved by introducing new functionality and improving the algorithm for reading data.

The article presents the possibilities of using game simulator Software Inc in the training of future software engineer in higher education. Attention is drawn to some specific settings that need to be taken into account when training in the course of training future software engineers. More and more educational institutions are introducing new teaching methods, which result in the use of engineering students, in particular, future software engineers, to deal with real professional situations in the learning process. The use of modern ICT, including game simulators, in the educational process, allows to improve the quality of educational material and to enhance the educational effects from the use of innovative pedagogical programs and methods, as it gives teachers additional opportunities for constructing individual educational trajectories of students. The use of ICT allows for a differentiated approach to students with different levels of readiness to study. A feature of any software engineer is the need to understand the related subject area for which the software is being developed. An important condition for the preparation of a highly qualified specialist is the independent fulfillment by the student of scientific research, the generation, and implementation of his idea into a finished commercial product. In the process of research, students gain knowledge, skills of the future IT specialist and competences of the legal protection of the results of intellectual activity, technological audit, marketing, product realization in the market of innovations. Note that when the real-world practice is impossible for students, game simulators that simulate real software development processes are an alternative.

In order to receive rapid (within a few seconds) evaluation of parameters of ionospheric radio channel near the MUF it is proposed to use new algorithm (method) of multi-frequency diagnostics of radio waves distribution channel. Such diagnostics will allow to evaluate accurately the optimum working frequency (OWF) for ensuring maximum capacity (MC) of radio channel. The new method is based on utilization of priori information about the parameters of the ionosphere along the radio path together with the data of current radiosonde in the radio channel for optimum valuation of the OWF-MC

The size dependences of the Fermi energy of metallic films of Al and Pb bordering with the dielectrics SiO2, Al2O3, HfO2, ZrO2, and TiO2 have been calculated. The model of free electrons and an asymmetric potential well has been modified by the introduction of the effective masses of electrons in the metal and in the insulator. The evolution of the size oscillations of the Fermi energy of metallic films in different dielectric surroundings upon the variation of the effective masses of electrons both in the metal and in the insulator has been analyzed. It has been shown that the allowance for the effective mass of electrons in the metal leads to a more substantial change in the position of the Fermi level in comparison with the allowance for the effective mass of the dielectric.

The article outlines the principles of correction of the ionosphere model in real time. These principles are based on the tabulation of mathematically complex (integrated physical and empirical) models on the section of a particular path (cross section) with sufficiently fine space grid, for development of effective reinstating algorithm for the cross section, for adjustment of values of the model in the grid points, according to informative value of used radio physical measurements performed in real time, for utilization of graphical display of the cross section structure of the model for the purpose of ensuring effective actions of the operator related to optimization of the parameters of the correction mode.

The size dependences of the Fermi energy of 1D metallic systems with an elliptic cross section in a dielectric medium has been obtained in the model of free electrons and a cylindrical potential well of finite depth. The calculations have been carried out for Au wires in SiO2 and in Al2O3. It has been shown that a change in the geometry of the cross section and the presence of the dielectric environment lead to a decrease in the Fermi energy, whereas the general character of the size dependences is preserved.

Analytical expressions for the size dependence of the Fermi electronic energy of ultrathin metal films on a dielectric substrate have been derived in the model of free electrons and finite-depth asymmetric potential well. The work functions have been calculated for Al films on SiO2 and Al2O3. It has been shown that the presence of a dielectric leads to a shift in the work function, while retaining the general character of the size dependences.

The influence of the geometrical shape of the cross section on the energy characteristics of a metal nanowire has been investigated theoretically. The size oscillations of the Fermi energy have been calculated within the model of an infinite potential well in terms of the perturbation theory. The calculations have been carried out for Au and Al. It has been shown that the cross-sectional ellipticity with a low eccentricity can be taken into account in the first-order perturbation theory by modifying the boundary conditions for the radial wave function of electrons.

The optical properties of an ensemble of metallic nanoparticles in an insulating matrix have been studied in terms of the classical Maxwell Garnett theory. To estimate the quantum effects, the analytical expression for the dielectric function of a metallic particle in the form of a parallelepiped has been used that was derived within the model of free electrons and potential well of infinite depth. The absorption coefficient has been calculated for composites with particles of various metals in various matrices.

The energy spectrum of electrons in a metal nanowire with a periodically modulated surface has been found in the framework of perturbation theory. To solve the problem, a transition is made into a coordinate system that “smoothes down” the surface oscillations. The influence of the surface modulation amplitude on size-induced oscillations of the Fermi energy in such systems is analyzed. It is shown that an increase of the modulation amplitude leads to a decrease of the Fermi energy in the wire. Specific calculations were made for Au, Cu, and Al wires.

Optical properties of a system of metallic nanoparticles in a dielectric matrix are studied. An analytic form of the dielectric function for a metallic particle having the shape of a parallelepiped is used to estimate quantum effects. The absorption coefficient in composite materials containing particles of various metals in various matrices is calculated, and a comparison with available experimental data is performed.

The article describes the introduction of cloud services in the educational process of the discipline «Databases» of future teachers of informatics and the design of the cloud oriented learning environment on their basis. An analysis of the domestic experience of forming a cloud oriented learning environment of educational institutions is carried out, given interpretation of concepts «cloud oriented distance learning system», «cloud oriented learning environment in the study of databases», «the design of the cloud oriented learning environment in the study of databases for future teachers of informatics». The following stages of designing COLE are selected and described: targeted, conceptual, meaningful, component, introductory, appraisal-generalization. The structure of the educational interaction of subjects in the study of databases in the conditions of the COLE is developed by the means of the cloud oriented distance learning system Canvas, consisting of communication tools, joint work, and planning of educational events, cloud storages.

The size dependence of the Fermi energy of conduction electrons has been analytically evaluated and its oscillations have been calculated in the framework of the cylindrical well model. The conductivity tensor components for a metal wire with the radius ρ0 have been calculated with the use of the expansion in powers of ρ0/λ, where λ is the wavelength of incident light. The influence of the dimension of the systems has been established by comparing the results of the calculations of the optical conductivity of thin wires and films for Au, Al, and Pb metals. According to the results of the calculations, the real and imaginary parts of the conductivity depend substantially on the size and frequency. The difference between the results obtained for Pb and Au metals has been explained by the different relaxation times of electrons in nanowires that are homogeneous in the thickness.

The transmission of infrared electromagnetic waves through quasi-homogeneous thin metal films is investigated within the diagonal response approximation. An expression for the dielectric function is derived in the framework of the finite-depth potential well model with due regard for the size dependence of the Fermi energy. The transmittance of the films is calculated, and the results of the calculations are compared with experimental data. The calculations are performed for Al, Au, and Ag.

Effects of single-electron tunneling charging and Coulomb blockade in a cluster structure (molecular transistor) with regard to the quantization of electron levels in an island electrode are investigated. The spectrum of electrons is calculated for small disk-shaped clusters. Restrictions connected with the Coulomb instability of the cluster and electron relaxation are introduced in the theory. The current gap and its voltage asymmetry are calculated for single-electron transistors based on small gold clusters. The effect of the cluster shape on the current gap is investigated.

The effects of single-electron tunnel charging and Coulomb blockade in a cluster structure (molec- ular transistor) are studied theoretically with allowance for the quantization of the electronic levels in an island electrode. The electronic spectrum is calculated for small spherical and disk-shaped clusters. Under the assump- tion that the total energy of the system is conserved with inclusion of the contact potential difference, equations are derived for analyzing the current-voltage characteristic. Limitations associated with the Coulomb instabil- ity of a cluster and with electron relaxation are introduced into the theory. For single-electron transistors with small gold clusters, the current gap and the asymmetry in its position on the voltage axis are calculated. The current gap is shown to vary nonmonotonically with the cluster size.