The current-voltage characteristics and current kinetics under influence of ethanol at constant applied bias voltage were measured and compared for the Si-based photovoltaic cell with Si3N4 anti-reflective layer and for the uncovered one. It was shown that porous anti-reflective film acts as a barrier for molecules of analyte and its presence leads to decreasing of adsorptive response of the...
Bandages from the radiation cross-linked hydrogels show by itself elastic films with thickness h = 2÷4 . 10-3 m – transparent jelly sterile material, that with C = 85÷90% consists of distillate water. Such bandages for wounds for the grant of the urgent help at bleeding, burns must be biologically compatible and not stick to the wounds. They can contain antiseptic, anaesthetic, haemostatic....
Samples of aluminium alloy Al(2024) and titanium alloy Ti-6Al-4V are irradiated with 2 keV helium (He) and argon (Ar) ion fluxes using FALCON ion source. Cone-like structures are found to be formed on the surface of two Al(2024) samples due to both irradiation conditions: Ar and He exposure reaching total charge 150 Coulomb per sample. Ar exposure of Ti-6Al-4V causes cones formation. He...
Solutions are obtained for the Schrödinger equation for an open semiconductor spherical quantum dot with a shell that is embedded in a medium of another semiconductor. The analytical solutions are exact for the zero orbital quantum number and approximate for l=1÷3. These results can subsequently be applied to the calculation of the permittivity of a similar system.
It was detected, compared and generalized the patterns of changes in the level of decrement of oscillations (DO) of dislocation low-frequency external and internal friction generated after exposing samples of materials with differing original structural conditions to pulses of a weak magnetic field (PWMF), each time in a new mode, which was changed 52 times.
In this paper we consider the possible way to create a system for automatically measuring of carbon dioxide concentrations in industrial premises as well as the light and sound staff alert when exceeding the maximum permissible concentration, which can lead to lethal effects. The system for the automatic CO2 concentration measurements is developed on the basis of the microcontroller AVR ATmega...
The developed algorithm for processing ARPES spectra by the method of curvature, the presence of abnormal dependence on the temperature (red-blue offset) at the M point of the Brillouin zone is confirmed. That explains the blockage of the jump between the closest neighbors and is consistent with the Fermi Landau Land Model. The dependence obtained in the center of the Brillouin zone...
It was investigated the cluster formation processes into ferrofluids for great magnetic nanoparticles ensembles. It was shown that such processes depend on magnetic field magnitude and magnetic field application time.
The results of spectroscopic studies of plasma arc discharge between tungsten and molybdenum electrodes are presented. Atomic emission lines and continuous spectrum were observed during experiment. Continuous spectrum was assumed as result of heated macroscopic particles emission, so it can be modeled by Planck's law. The temperature of such particles was estimated in this way
The waveguide segment limited in the direction of wave propagation is a resonator the resonance frequency of which is determined by the length of this segment l. This also applies to surface plasmons. Thus, a separate metal plate (or film) on the dielectric substrate can be a resonator. Such resonator is called a surface wave resonator (SWR). The system of two such resonators has rather...
Theoretical model for resonator eigenmodes HE±11δ in the cylindrical cavity with ferrite layer on metal end-face in T-wave approximation was developed and compared with experiment. Experimentally obtained effective tuning of HE+11δ resonance frequency was 0.2 MHz/Oe at ferromagnetic antiresonance frequency, that one order less that typical frequency tuning in ferrite resonators by...
Typical frequency dependence of the output dc voltage generated by a spin-torque microwave detector (STMD) based on the magnetic tunnel junction is almost symmetric which makes difficult to determine microwave signal frequency using only one nanostructure. Previously it was shown that two STMDs can be used as a spectrum analyzer in the short range of frequencies between the resonance...
The surface electromagnetic wave resonator has a fairly simple design. It can be used as a non-destructive analyzer of the properties of the material of its surface. The method of determining the surface resistance of a surface electromagnetic wave resonator is proposed. The proposed method specifies the specific surface resistance of an unknown material, based on various materials of the...
The paper presents the results of finding of microdischarge reduced electric field. Current-voltage characteristics were measured for distances between electrodes 0.5-4.5 mm. Microdischarge based on rotating discharges in vortex flow. Air was used as a plasma forming gas.
Created application checks whether the first graph is isomorphic to the second one. Conclusions about the practical use of this program and its benefits were made.
Photonic methods for generating and detecting THz signals are a subject of a great research activity in recent years because such systems combine the potential of a high THz wireless communication capacity with a long-range fiber-optic communication potential. We propose the new design scheme of dual-frequency fiber Raman laser in our work and its advantages in comparison with semiconductor...
This paper demonstrates the influence of gold nanoparticles incorporated into monocrystalline silicon solar cells using electrodeposition technique. It was determined that the presence of nanoparticles into the solar cell led to an unequivocal increase of short-circuit current. The largest increase in short-circuit current is observed for p+/n/n+ -structure of solar cell and nanoparticle size of 90 nm.
The model of electrical breakdown in a mixture of carbon dioxide and nitrogen in conditions similar to that on the surface of Mars is presented. The model includes reactions of impact ionization, associative attachment, dissociative recombination, excitation of oxygen atoms, charge exchange reactions, and electron and ion losses on dust particles. The magnitudes of the breakdown electric field...
The emulator of the modular measuring system is implemented in order to use for study of the measuring system program control. The emulator has advanced graphical system which represents the complete configuration of the measuring system. In the process of performing a laboratory task, the student writes the text of the program (on C++ or C#) in the console application projects implemented as...
A study was conducted on the influence of the reaction chamber material on hybrid plasma-catalytic ethanol reforming. A comparison was made between the reforming in quartz and steel reaction chamber with the same geometry. Discharge behavior was investigated using current and voltage oscillograms, optical emission spectra and video capture. The composition of gaseous reforming products was...
Freestanding porous silicon carbide (PSiC) was synthesized via electrochemical etching of silicon carbide (3C-SiC). The surface morphology of PSiC has been studied using scanning electron microscopy (SEM).The electrical properties of porous SiC structures were investigated using impedance measurements in dry air and in saturated vapor of ethanol.
A model of the fiber-optic links with the use of wavelength-division multiplexing technology on the example of the URAN network in Poltava is proposed. It is suggested to carry out the modernization of the existing network using coarse wavelength division multiplexing technology. Based on the analysis of the network topology in Poltava, there is presented a variant of equipment placement for...
Azimuthal surface waves (ASWs) are eigen modes of the cylindrical plasma-dielectric-metal structures both in presence and without axial d-c magnetic field. They are actively studied due to possible applications in plasma electronics, radiophysics, nanotechnologies, and biomedical diagnostics. Higher radial modes are known to propagate at higher frequencies and shorter wave lengths as compared...
The purpose of the work is to propose an improved procedure of both material parameters (complex permittivity ε and permeability μ) determination from the measured microwave scattering parameters. A qualitative analysis revealed that analytical methods give inaccurate and unphysical results in the resonance regions. Nowadays there exist a couple of improved only permittivity determination...
TRPA1 and TRPV1 channels are nonselective Ca2+ channels and regulate intracellular calcium levels. Deviation from the normal level of calcium in the cell can lead to a number of pathologies in the nervous system, including neuropathy and pain syndromes. The purpose of this work was the experimental studies of interaction of TRPA1 and TRPV1 channels, their sensitivity to selective agonists -...
In this work, the behavior of secondary spin waves (SSW) arising under the action of parametric pumping in normally magnetized films of yttrium-irongarnet (YIG) was investigated. SSW frequencies differ from the frequency of parametric spin waves (PSW) with longitudinal pumping and correspond to the position of the bottom of the spin-wave spectrum. The dependences of the threshold of parametric...
The reliability of the integrated circuit and the performance of its functions strongly depend on the quality of the contacts.
Widespread misconception that formation of wire chip connection is a simple process. This process is complex and requires a thorough understanding of the metallurgy, thermodynamics, and surface chemistry involved.
To evaluate the impact of various factors...
The non-planar angular dependence of the ferromagnetic resonance (FMR) was measured for CoFeB, films of different thicknesses made by magnetron sputtering. Angle outside the plane the dependence of the FMR resonance field and the line width were analyzed using the Landau-Lifshitz-Hilbert equation with allowance for broadening of the line width due to magnetic inhomogeneities in the film....
Classic ferrofluid (FF) is a colloidal suspension of magnetic nanoparticles in a carrier-liquid, which stabilized by surfactant. FF is a unique substance that combines liquid properties (viscosity, fluidity, surface tension, etc.) and ability to interact with the magnetic field. Although there were made many different investigations of FF, full classification of aggregate formation and...
The temperature dependence of the dielectric permittivity of PZT piezoceramics based on solid solutions of lead zirconate-titanate oxides has been obtained. It is established that the temperature dependence of the permittivity of PZT piezoceramics is satisfactorily described by the exponential function. Different values of the activation energy for two temperature regions indicate the...
Ion implantation of Be in semiconductor material InSb to create semiconductor diveces, like a photodiode. Process of forming doped by Be monocrystal InSb.
The results of an optical experiment on light focusing through a strongly scattering medium are described. The principal possibility of obtaining one and two focal spots by the use of binary amplitude modulation of incident light with the aid of a liquid crystal spatial light modulator is shown.
The work is devoted to investigation of ITO films at temperatures close to the temperature of liquid helium. Using the theory of quantum corrections to the theory of conductivity, the theoretical values of the magnetoconductivity were calculated and compared with the experimental data obtained earlier in the laboratory.
Іn this work the silicon nanopillars were produced by means of metal assisted chemical etching in two stages. It was determined that using the amount of AgNO3 of 68 mg in the first solution and the duration of the first stage of 20 sec made possible to reduce the sunlight reflection of silicon substrate from 20-30% to 10-12%.
The maximum power of the amplified spontaneous noise in silica single-mode fiber (SMF) is studied experimentally as function of the pump power variation in the idle mode of counter-pumped fiber Raman amplifier (FRA). Method of Gaussian filtration of detector noise in the amplification spectra of fiber Raman amplifier is presented.
In this work it was investigated the structural, electrical and optical properties of molybdenum oxide thin films, which are synthesized by ion-beam sputtering,depending on technological parameters. It was found the possibility to increase transparency of the material by twice, and its electrical resistance to 3-4 orders of magnitude by changing the temperature and time of deposition.
In this paper c-Si/nc-SiOx heterostruсture photovaractors were synthesized by means of RF magnetron sputtering method. Influence of illumination and deposition temperature of silicon on electrical and optical properties of photovaractors were studied. Under illumination conditions the output capacitance of photovaractors was increased by 7 times. Overlap ratio for these structures was in a...
Thin polymer films have numerous technological applications in various industrial and biomedical sectors related to protective and functional coatings, non-fouling biosurfaces, biocompatibility of medical implants, separations, advanced membranes, microfluidics, sensors, devices, adhesion, lubrication and friction modification[1]. In many cases, the films can be of complex composition with...
In this paper, we report about computer simulation of nanoparticles deposition from the rarefied plasma onto the solid substrate. In our model, we used equations of cold hydrodynamics for ions, the equilibrium Boltzmann distribution for electrons, and PIC method for modelling of nanoparticles. It is shown that charged nanoparticles can change the sheath, so that deposition of nanoparticles on...
In this paper we numerically study the phase-locking effect in one-dimensional (1-D) and two-dimensional (2-D) arrays of spin-torque nano-oscillators (STNOs) consisting various number of oscillators (2 and 4). Our calculation results show that the efficiency of STNO synchronization depends on the geometry of oscillator array and the spread of oscillator eigenfrequencies. In particular linear...
We describe the quartz-wedge depolarizer composed of two wedges of the anisotropic quartz. The wedges have the same geometry but the differently directed optical axes, which lay in plain, that are parallel to straight faces of wedges. The adjoined by inclined faces wedges form the depolarizer which depolarization power depends on the incident light beam radius: the larger depolarization power...
The influence of the instability parameters and the irregularities of the magnetic fields of the gradient system on the quality of tomograms was studied by methods of processing real tomographic images. It is shown that the possibility of obtaining reliable diagnostic information depends on the type of image. Three types oft he reconstructed images for different values of signal deviation from...
A review of some existing Сombinations of Genetic Algorithms and Neural Networks (COGANN). In its most general form, COGANN can be supportive or collaborative.
The most common used approach of wavefront measurement is based on the sampling light amplitude distribution. By analyzing intensity patterns derived from reference and object wave, the local front slopes can be measured. The new approach for referenceless wavefront reconstruction is proposed by using the Talbot sensor. It is shown, that by comparing the images of an object wave produced in...
In order to identify a physical mechanism responsible for the resistive switching effect in memristive oxide-based structures, we propose to study an ac response to a periodic current or voltage perturbation. A minimalist model which accounts for the frequency impact on hysteresis phenomenon in current-voltage characteristics of the yttrium-barium-cuprate YBa$_{2}$Cu$_{3}$O$_{7-c}$ (YBCO)...
The uniqueness of topological insulators lies in the presence of the topologically protected electronic surface states. The study of the electronic structure of these states allows us to find new applications for topological insulators in electronics, especially as a material for spintronic devices. The electronic structure of bismuth selenide and compounds with tellurium, which are...
Measurements of the magnetization curves for mechanical deformations of composite layered structures with ferromagnetic and piezoelectric properties and simulation of these curves on the basis of Stoner-Wolfart's model made it possible to explain both the physical processes occurring with magnetic subsystem under deformation and features of the curve shapes for the purpose of adaptation the...
We develop a C-code based spin-lattice simulator SLaSi for magnetization dynamics in ferro- and antiferromagnets. It solves discrete dynamical Landau-Lifshitz-Gilbert equations taking into account exchange and coordinate-dependent anisotropy defined in terms of local discrete Frenet-Serret reference frame calculated on fly. Runge-Kutta-Fehlberg integration scheme of 4-5 order is used for...
Interaction in the system ‘cells-viruses- nanoparticles’ has been simulated. The case of the viruses ‘pretreatment’ with nanoparticles and their further introduction to the cell culture has been considered. The model takes into account the growth restriction and the probability of adsorption and desorption. The model can be useful in medical physics while studying the virucidal action of...
The studying of the photocurrent relaxation kinetics in Si-CdTe-ZnO semiconductor heterostructure at illumination of light of 632 and 458 nm wave lengths and influence of light on sensitivity to ethyl alcohol vapor was carried. It was shown, that photocurrent relaxation kinetics is qualitatively dependent on the wave length of illuminating light, and the light causes growth of adsorptive response.
Abstract: The process of surface modification of PZT ceramics by hydrogen atoms of thermal energies has been investigated. The change in surface electrical conductivity of the PZT ceramics by hydrogen atoms was studied. It was found that the change of the surface electrical conductivity was the result of reducing the surface layer of PZT ceramics. Mechanism of surface electrical conductivity...
We modeled IV-characteristics and dynamics of excitations produced in the long Josephson junction by the inhomogeneous distribution of critical currents. Zero-field steps were observed in IV-curves. We proved that the oscillation movement of fluxons took part in the formation of zero-field steps.
An increase of the magnetic susceptibility on 8% of a paramagnetic titanium alloy VT3-1 upon its multiple processing in a permanent magnetic field with induction B=[0,25÷1,0] T was found. If we make an analogy with ferromagnets, the obtained results of the dependence of the magnetic susceptibility of the titanium alloy VT3-1 on the preceding magnetic state make it possible to speak of the...
The nonlinear internal dynamics of one-dimensional topological magnetic solitons in antiferromagnets were studied theoretically, taking into consideration their real magnetic symmetry [1]. The presence of the Dzyaloshinskii–Moriya interaction (DMI) in the general form, which is not reduced to a purely antisymmetrical form, leads to appearance a gyroscopic term in the Lagrangian system. It was...
Efficient method for ion-electron Coulomb scattering for particle-in-cell simulation was proposed, the simulation results of the initial stage of beam-plasma instability with and without allowance for Coulomb scattering are presented, the effect of scattering on the plasma heating is discussed.
Voltage oscillations that arise when high-density currents flow through silicon with dielectric isolation (SDI) structure have been obtained and investigated. The investigations have been conducted in pulsed mode. Volt-ampere characteristics of SDI structure and distinctive parameters of oscillograms for both relaxation and quasi-harmonic oscillations have been studied. We have proposed a...
The using of devices in such areas as meteorology, agrarian sphere, protection and etc requires special conditions for energy supply. Most IoT devices used in these industries are located in areas with unstable power supply and complicated access to equipment. In this regard, there is a question of the uninterruptible power supply for these devices. Сonsidered the possibility of using...
