We calculated [1] a spin-polarized conductance in the almost unexplored nanostructure "high temperature ferromagnetic insulator/ graphene/ ferroelectric film" with a special attention to the control of electric polarization direction and value in a multiaxial ferroelectric film by a misfit strain. We proposed a phenomenological model taking into account the shift of the Dirac point due to the...
TlBr has been recently studied as a compound-semiconductor radiation detector operating at room temperature, because of its large atomic number (Tl:81, Br:35), high density (7.56 g/cm3) and large band gap of 2.68 eV, which makes it suitable for room temperature operation, it has the necessary low thermal noise. In addition, it has a low melting point of 460°C, which facilitates crystal growth,...
CdTe has been used as an X-ray image detector because of its high sensitivity, energy and spatial resolution, and room temperature operation. In order to build image detectors, it is necessary to bond CdTe pixel elements to a signal-reading LSI, and it is necessary to maintain the performance even if it is added heat treatment in order to use an efficient method for making contacts with the...
The standard for imaging equipment called UHD, has features such as high resolution, wide color gamut, and wide dynamic range compared with standard for HD. wide color gamut displays such as UHD compatible displays has been considering for application not only in the entertainment field but also in the medical and industrial fields. It is considered important for imaging equipment used in the...
Photon counting type detectors can record incident photons along with their energy.Spectral X-ray imaging with this photon counting type detectors, which measures X-ray photons with each energy, is expected to identify material and improve contrast by utilizing the interaction with substances that differ depending on the energy of X-rays.Due to the characteristics of the ...
X-ray imaging has been widely used in the fields of medical examinations, non-destructive testing, and security as observing the interior of objects due to its high penetrating power. Spectral CT can provide high contrast even for objects with similar densities, and can distinguish materials by using energy information. On the other hand, the amount of information about interior of objects...
X-ray imaging is used in variety of fields such as medical, industrial and security fields.
Photon counting type X-ray image detectors have been developed in our group. Compared with current-integration type detectors which is used as a conventional type detectors, photon counting type image detectors can eliminate noise such as thermal noise and leakage current by setting a threshold value...
This study is about to developing an imaging instrument using a small neutron source. X-ray penetration image and neutron penetration image have a complementary relationship. The neutron penetration imaging has advantage of structural analysis of materials containing light elements than X-ray penetration imaging, and it can image interior of thick metals due to its very high transmission...
Photon counting, which measures the energy information of X-ray photons, is an advanced imaging technique in X-ray imaging. One of the merits compared with the conventional energy integrating detectors is the high sensitivity for detecting individual X-ray photons. On the other hand, the range of detectable doses is limited by the pile-up effect in which the detection of multiple photons...
Deflection, a general wavefront manipulation functionality, which is often considered as a characteristic attribute of gradient metasurfaces, is numerically and experimentally investigated at near-infrared for a simple reflection-mode meta-grating comprising just one Si nanorod per period. Different deflection scenarios are demonstrated that enable different functionalities and multifunctional...
Chalcogenide glasses are known as perspective materials of optoelectronics with a high optical transparency in the infrared region of telecommunication windows 3-5 and 8-12 μm. In this work, influence of composition on structural transitions and optical properties of chalcogenide glasses was studied by Raman technique. Obtained Raman spectra chalcogenide system...
The random lasing (RL) in the multiple scattering active media can occur together with the stimulated Raman scattering (SRS) and form a quasilinear secondary emission spectrum under conditions of the diffuse light propagation. Under these conditions, the stimulated Raman scattering spectrum obtained from the secondary emission spectrum is a more structural than the spontaneous Raman spectrum....
Lock-in amplifiers are widely applied in optical measurements when desired signal buried in noise. In the same time commercial broadband lock-in amplifiers that can make such measurements are expensive. This article presents design of lock-in amplifier that can be used in one-phase, two-phase mode or as two parallel one-phase amplifiers. It is completely digitally-controlled and may be...
Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs) are widely used in high-density integrated circuits for amplifying and switching electronic signals. MOS transistors produced by the silicon on insulator (SOI) technology yield a high switching speed, reduced power consumption and provide a flexible architecture by varying such parameters as thickness of a Si layer and...
We investigate thermalization in a quantum Fermi - Pasta - Ulam - Tsingou problem for anharmonic vibrations in atomic chains applying semi-quantitative analysis of resonant interactions complemented by exact numerical studies. We estimate the energy at transition from the localized low-energy phase to the chaotic high-energy phase. The transition energy is inversely proportional to the number...
Laser-induced periodic surface structures (LIPSS) are very common phenomena that arises from interaction between different surfaces and femtosecond laser pulses. Characteristic size of such structures is laser wavelength order and typically belongs from nano- to micro-scale range. Searching new material surfaces for the nanostructuring are significant scientific interest of these days. We are...
A change in the structure of a material under the action of laser radiation can occur if the energy of light, transmitted to some area of the material, exceeds the energy of interatomic bonds in this area. The magnitude of the excess and the time, during which the energy is transferred, are both important. If the duration of the laser pulse is longer than the time of thermal relaxation, then...
Ultrafast lasers can be used to produce sound waves in a medium. Usually, the laser beam is focused onto the sample that partially absorb the light. The transient heating of the sample produces transient mechanical stresses that lead to ultrasonic transduction. Since the discovery of ultrafast lasers, the generated sound waves have reached ultrafast timescales, in the picosecond regime, with...
Germanium tin (GeSn) semiconductors are promising absorber/emission materials for the novel infrared (IR) optoelectronic devices. The main advantage of these materials is the possibility to obtain a higher absorptivity in comparison with indirect-bandgap crystalline silicon, germanium, and their alloys. The GeSn/Ge/Si heterostructures were grown by a chemical vapor deposition method. An...
The study in non-equilibrium conditions of an emblematic class of quantum materials, the Mott insulators, is currently developing into an active and fruitful branch of solid-state physics. Recent researches indeed demonstrate that Mott insulators excited either by ultrafast infrared or THz laser pulses or by electric fields might display non-trivial insulator to metal transitions (IMT’s) whose...
In a photonic crystal fiber (PCF), the use of air hole as a core provides the ability to guide light in the air. The light is trapped in the defect in photonic crystal, as an application for this type of fiber, there is the high-energy transfer, endless single mode and fiber sensors, which measure physical parameters (temperature, pressure, force, etc.)
Many numerical tools exist to model...
The Optical fiber-based network also known as Fiber To The Home (FTTH) that is the future solution for providing broadband service such as voice, data and video (Triple play).This paper addresses the concept and deployment of Fiber to the Home (FTTH) for residential condominium based on the ITU-T G.984 standard Gigabit passive optical network (GPON) to reach a capacity of the maximum...
This article presents an analysis of the substrate variation effect for a new design of graphene polygonal patch antenna for Ka-band applications, Where an application of graphene as radiating patch for satellite applications; will be proposed to ensure the proper functioning of this antenna for Ka-band , the effectiveness of graphene planar antenna will proved by a numerical simulation by CST...
High-speed transmission is essential in telecommunication systems and increases according to the needs of users for various applications such as live broadcasting, video on the Internet, videoconferencing, etc. In this paper, we describe our optical communication network. Moreover, we have shown the influence of several parameters on the transmission quality of Optical Local Area Network...
The brain has always been the master of all human organs, being responsible for all voluntary or involuntary activities. For that, the brain is a subject of a many research such as neurobiology, neurology, psychiatry, psychology, linguistics, anthropology... Among the many methods of exploring the brain, the basic technique is EEG electroencephalography.
The electroencephalogram (EEG) is...
Photoplethysmography (PPG) is an optical measurement for observing changes in blood volume in a tissue non-invasively.
Photoplethysmography in the infrared is based on two principles: the presence of a pulsatile signal generated by the arterial blood and the differential absorption of oxyhemoglobin.
As part of this work, we present a formatting circuit of PPG signal in the infrared. This...
In recent decades, light became one of the most versatile components for diagnosis and therapeutic purposes. Advancement in optical science and engineering had led to invention of a wide variety of non-invasive and minimally invasive apparatuses and procedures that are inseparable from today’s medicine; namely OCT, PDT, etc. The common component of all of these methods is propagation of...
The evolution of telecommunication networks towards the transport of multimedia data (internet, telephony and IPTV) makes it necessary to seek systems offering high bandwidth and multiple access to resources. The optical network currently represents a reliable solution thanks to the qualities of the fiber (transmission channel) and the development of FTTH (Fiber To The Home) technology and...
Multicomponent amorphous metal alloys with ferromagnetic properties are a class of optoelectronic materials with unique set of optical, mag-netic and electrical properties. An important problem is the diagnostics of elastic-stress state of amorphous ribbons after their production by rapidly quenched method. In this paper to characterize the elastic-stress state of the $Ni_{78}Si_{8}B_{14}$...
Raman spectroscopy is an important and informative source of information about dye molecules structure and its interaction with the matrix. However, very intensive luminescence of lasing strongly interferes detection of weak Raman scattering radiation. The use of conventional techniques of Raman spectra observation is restricted and complicated due to intense dye luminescence and wide...
Melanins are a class of organic compounds that act as pigments in living organisms. Melanins also play an important role in the human body. In particular, they protect tissues from the harmful effects of ultraviolet and other types of ionizing radiation as well as other aggressive carcinogens.
Melanins are pi-electron systems that absorb and emit light in the ultraviolet and visible...
The brain has always been the master of all human organs, being responsible for all voluntary or involuntary activities. For that, the brain is a subject of a many research such as neurobiology, neurology, psychiatry, psychology, linguistics, anthropology... Among the many methods of exploring the brain, the basic technique is EEG electroencephalography.
The electroencephalogram (EEG) is...
The confinement of light in multiple scattering media (MSM) leads to the stimulated emission appearance, which called random lasing. Multiple scattering of light plays the role of nonresonant positive feedback which replaces the cavity mirrors in conventional laser. In real MSM having limited size, boundary reflection significantly affect the feedback.
In the presented work we held numeric...
Zinc selenide (ZnSe) is one of the wide-gap АІІВVI materials and is widely used in semiconductor electronics. Specially undoped ZnSe single crystals can also be used as a semiconductor detector. In this regard, there is need for a complex study of electric and luminescent properties of ZnSe single crystals.
There was performed complex experimental research of X-ray conductivity (XRC), X-ray...
In this work, we used an aqueous solution of the thermosensitive dye rhodamine 6g for contactless control of heating in a microwave oven. Temperature dependence of spectral parameters in the range of 20-100 ° C, measured using a conventional contact heater. Relative intensity, peak wavelength, spectral bandwidth, and asymmetry coefficient exhibit approximately the same temperature sensitivity...
The Eu3+-doped vanadate luminophores are widely used in optoelectronic devices for more than 50 years. At the last years, a great attention was also paid to investigation of vanadate matrices with other rare-earth luminescent activators, in particular - Sm3+ ions. In this paper we report results of synthesis and investigation of the Ca2+-doped La1-xSmxVO4 (0.05 ≤ x ≤ 0.2) nanoparticles...
The paper analyzes the modern widespread microscopy techniques as wide-field, laser scanning confocal and structured illumination microscopy.
Wide-field microscopy is a technique, which provides fast imaging capture because all the field of view is illuminated uniformly. However, this technique has limitation in capturing 3D images using the software for digital focus extension. It also...
The report deals with the dependence of the period of the laser-induced periodic surface structures (LIPSS) on wavelength of incident laser radiation with the aim to make another step in the elucidation of the nature of LIPSS formation. The dependence of the LIPSS period on the wavelength of laser radiation could reflect the dispersion dependence of surface plasmon polaritons (SPPs) that take...
The influencing of ultrasonic (US) deformation εUS was researched on anelastic and elastic characteristics of nano composites of multiwalled carbon nanotubes (MWCNT).
It’s showed, that anelastic internal friction (IF) Q-1 and elastic modulus Е characteristics are essentially depended from morphology of surface layer [1]. The complex elastic modulus of polyvinyl chloride (C2H3Cl)n,...
MoS2 emerged as promising candidate for photovoltaic, light emitting, optoelectronics and sensing applications. However, photoluminescence (PL) of 2D materials is still limited that motivates the researchers to explore the ways to enhance it. Plasmonic enhancement is one of best way to improve the PL in which, nanoparticles resonate with the free electrons present on the surface of 2D...
The mechanisms of potassium (K) and cesium (Cs-137) uptake by plants were studied using radish as an example. The investigations were performed at four experimental field sites within the 10 km Zone of the Chornobyl Nuclear Power Plant in 2012 and 2013:
Radish seeds were sown, and plants and their corresponding soil solutions were sampled, several times during each growing season. The...
These last decades the world has known a major development in the medical sector in general and in the well-being of personnel in particular, where the appearance of neuromuscular stimulators have responded to the various treatment of therapy.
A large number of dysfunctions within the nervous system cannot be resolved by conventional classic therapeutic without side effects. To resolve this...
In-fiber grating-based sensors have many advantages over conventional electric and alternative fiber optic sensor configurations. We proposed and fabricated an Eccentric Fiber Bragg Grating (EFBG) inscribed by Point-by-Point (PbP) in conventional single- mode fiber (Corning SMF-28) using an IR femtosecond laser. Potential applications of eccentric FBG in refractometry, sensing are further illustrated.
Hybrid organic-inorganic films are a promising material for use in dye-sensitized solar cells. The purpose of investigation was to study the optical properties of hybrid organic-inorganic films of CuSCN copper thiocyanate with stilbazolium dye of different concentration.
As a method of research the multiple-angle-of-incidence ellipsometry implemented in the device LEF-3M-1 with a wavelength...
The optical fiber is the privileged channel of transmission for broad-band communications. To respond to increasing needs, it is essential to improve the characteristics of optical fibers, primarily those relating to the chromatic dispersion. This negative phenomenon limits the transmission rates. This has the effect to canceling the chromatic dispersion only for the wavelengths above than...
The remarkable progress was achieved in the study of the physical and chemical properties of Hg3X2Y2 (X= S, Se, Te; Y= F, Cl, Br, I) crystals. Their optical properties such as high refractive index, photoconductivity, electrooptical effect, optical activity, optical nonlinearity etc., make them promising nanomaterials for nonlinear application. From the structural point of view, the corderoite...
First-principles calculations based on the density functional theory (DFT) were carried out to investigate the electronic and optical properties of semiconducting crystal Hg3S2Br2. The electron exchange-correlation energy was described by the generalized gradient approximation (GGA) and modified Becke-Johnson (MBJ) potential. The analysis of the band energy dispersion shows that the optical...
Polymer blends are widely used to obtain materials with improved characteristics. Interfacial tension (or surface energy) is one of the key parameters that determine the level of adhesion between the components of a polymer blend.
The composite under study is based on the polymer blend of PP/CPA and filled with Fe, which is localized only in the CPA phase. The study showed that concentration...
Ultraviolet (UV) light emitting diodes (LEDs) are gradually displac-ing gas-discharge UV sources due to advantages: greater energy effi-ciency, increased reliability, ease of wavelength and intensity changes, narrow spectral range, light weight and compactness. Application of UV LEDs are very diverse, in particular, are relevant applications where high power UV radiation is required -...
We have investigated the structural, morphological and optical properties of dibenzofluorene derivative, which is part of the new sub-class of dibenzofluorenes, due to its existence as a zwitterion, in contrast to other KuQuinones. Microstructural and morphological characterization data, as well as powder X-ray diffraction study, confirm the amorphism of dibenzofluorene derivative in the...
Amorphous chalcogenides have received much attention in recent years, due to their unique properties and versatile technological applications such as infrared optical elements, acousto-optic and all-optical switching devices, holography recording media etc.
The aim of this study is to carry out the detailed study of vibrational properties of the pseudo-binary...
3D X-ray microtomography (3D X-ray micro-CT) is a method of non-destructive layer-by-layer examination of the internal structure of an object. The method is based on measuring the attenuation of X-ray radiation depending on the density of the material that absorbs it. The object is scanned at different angles and by measuring the intensity of the absorbed X-ray radiation.
Various operating...
In this paper we developed a unified equations describing ellipticity of reflected light as a function of off-diagonal dielectric tensor components in magneto-optical Kerr effect. The approach allowed us unifying numerous published results which introduced equations for experimental data analysis having different signs and absence/presence of imaginary unit at complex refractive index. The...
We developed a theoretical approach based on electron gas in a metal with angular momentum coupled to magnetic field in order to explain magneto-optical (MO) properties of ferromagnetic alloys. In frames of the model the magnetic quantum number and Hund’s rule can be applied for ascertaining the MO alloys properties. Hund’s rule directly influences the dielectric tensor off-diagonal elements...
Synthetic calcium hydroxyapatite Ca10(PO4)6(OH)2 is very similar to the main mineral component of the hard tissues of living organisms. Thus, it is actively used in innovative medicine as a filler for artificial bones, for the manufacture of implants, in dentistry, etc. Mostly, such objects are in the aqueous environment, and small clusters of water have recently been discovered inside...
The search and synthesis of modern nanomaterials, as well as an in-depth study of their physical properties, is a priority scientific and technical task. The uniqueness of properties of nanoscale and nanostructured objects is largely determined by atomic and electronic processes that take place both in volume and on the surface and significantly depend on the influence of dimensional effects....
Matrix isolation is one of the most effective methods to investigate individual molecules of small clusters by spectroscopic methods. Though the matrix material is inert, there is still an effect of low-temperature matrices on the structure and vibrational spectra of isolated molecules. The main purpose of this study is to investigate the argon matrix effect on the structure, dynamics, and...
Films with nanoscale thicknesses and nanoparticles are widely used in all areas of nanotechnology. Nanoparticles of gold are of great interest in physics, chemistry, biology, and medicine. Gold nanoparticles are non-toxic, chemically stable, and biocompatible with living tissue. Unlike bulk gold, nanostructures have unique properties - catalytic, ferromagnetic, and tunable optical properties....
In the element base of modern information technologies (monitors, lasers, sensors) use quantum dots that have extremely small sizes. Therefore, the development of mathematical models of various quantum dots (spherical, cylindrical, prismatic, conical), which allow to determine the eigenvalues of energy, is an urgent task. The results of the study of the dependence of the shape and parameters...
Merocyanine dyes are donor-acceptor polimethine molecules with unique spectroscopic properties used for design of advanced photonic materials, solar cells ets. Merocyanines, with their wide absorption bands, are suitable applicants for this goal. Optical characteristics of such compounds are very sensitive to a type of solvent, molecular concentration due to that methods and conditions of...
Design of new compounds for application in optoelectronic devices is one of the most actively developing branches of material science. In particular, various simple and complex oxides actively studied as materials for display panels and white light emitting diodes (WLED). Phosphate compounds doped with rare-earth (RE) ions were found to be one of the most promising for WLED applications due to...
A non-destructive method for the technological control of the structure defects by measuring internal friction (IF) and E after laser radiation was developed. The study of influence of structure defects on damping of vibrations in Si + SiO2 plates by the diameter of D = 100÷60 mm and by the thickness of hSiO2 ≈ 600 nm, hSi ≈ 400 000 nm allows to estimate the degree of perfection of crystalline...
Simple structure of insect’s compound eye, gives to us an opportunity to build very efficient and cheap optoelectronic vision systems for orientation, navigation and preventing collisions between unmanned air vehicles. Nevertheless, there are only a few designs that implement the idea of facet vision systems:
First one is a system that has micro-lens array on a matrix of photodetectors [1]....
High speed data rate is a very imperative requirement today and it is increasing according to the customer requirements for various applications such as live broadcasting, video on internet, video conferencing etc. This research is based on how we can design and analysis the optical fiber communication system. . WDM with enormous bandwidth and low energy consumption has been considered to...
The quasitransversal ultrasonic velocity V┴ = 756± 10 m/sec, shear module G = ρV┴12 = 554 MPa, Poisson coefficient μ ≈ 0,44, Debye temperature θD ≈ 71 K polyethylene with low density high pressure (C2H4)n were determined from the oscilloscopegramma. The ultrasonic (US) attenuation logarithmic decrement was δ_┴≈1,65×〖10〗^(-1).
If dislocation segment ξ(x,y), that are vibrated under the act of...
The study addresses an experimental approach aimed at facilitating the improvement of the Enzyme-Linked Immuno-Sorbent Assay (ELISA) performances. ELISA is a heterogeneous (plate-based) immunological technique widely used as a diagnostic tool. The principle of the assay lies in capturing the biomolecules of interest present in the liquid probe by the capture biomolecules immobilized to the...
The concentration dependence of the elastic module E(C) in polyvinyl chloride (C2H3Cl)n + multiwalled carbon nanotubes (MWCNT) can be described by a percolation model with the extremely low percolation “threshold” in the range 0.02 ÷ 0.1%.
The Poisson coefficient μ is equal to ratio of relative transversal compression ε┴ to relative longitudinal lengthening ε║ and equal [1]:
μ = ε┴/ε║ =...
Optical materials based on rare earth vanadates (REVO4) are widely used in science and technology because they are characterized by high absorption in a wide spectral range and effective energy transfer from vanadate host to the RE ions. Such compounds are used as luminescent light emitting materials and luminescent spectral converters. At the last years, nanosized orthovanadates have also...
