Intermolecular interactions in solutions are, as a rule, manifested by the shift of an absorption band of a chromophore molecule. When the shift of the wide (<1000cm^-1) molecular absorbtion and spectrum is considerably small (D 1/2=5000-10000 cm^-1), its direct registration is very difficult. The method of estimation of such shifts by means of registration of the difference spectra proportional to them is proposed. An example of the complex absorption spectrum of DNA shows that the best result for estimation of the band shift (D n ) can be achieved by calculation. The application of the method is demonstrated by the example of disturbance of DNA ultraviolet spectra at DNA interactions with double charged Mn²⁺, Co²⁺, Ni²⁺ и Zn²⁺.

Keywords: estimation shifts of absorption bands, intermolecular interactions, DNA ultraviolet spectrum, metal ions.

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Mathematical models of a photometric granulometric analyzer of the quantity and size of suspended particles in liquids have been developed. The models were used both for optimization of the metrological and constructional properties of the instruments under development and for developing the new principles of measurement results formation. Basing on photometric counting methods with the use of mathematical simulation, various types of particle analyzers/counters have been designed.

Keywords: particle analyzer, granulometry, simulation, mathematical model.

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The study considers an original approach to the problem of hologram spatial filters formation for the problems of optical data processing. Existing spatial filtration methods mean searching and further synthesis of the specialized optic processor optical transmitting function (OTF). The approach suggested by the authors consists in finding such an impulse response (IR) of dotted - or non-dotted- type which is a function convinient for mathematical manipulation corresponding to the optical system which perhaps does not exist but which becomes a physically realizable IR as the result of the required transformer L operator application. Realization in practice of the suggested approach considered in the study allows us to assume that it is possible to obtain an optical processor carrying out the operation of the vector q ~ modulation.

Keywords: data processing, optical system, spatial filtration, transmitting function, impulse response.

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At the interaction of a train of giant pulses of a high-power waveguide neodymium glass laser with a carbon target, a quasi-stationary laser plasma was created (at the 100 KHz giant pulses frequency). Raman scattering of the laser radiation by the CO and CO₂ molecules formed by carbon burning in the plasma-air boundary layer in the atmosphere was observed. It is shown that the velocity of plasma scattering decreases due to carbon burning that reduces the velocity of plasma cooling.

Keywords: laser plasma, neodymium laser, Raman scattering.

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The results of the work on developing the tractor driving automation, in which tractor orientation is performed by optical location, are presented. The tractor is "bound" to a light-contrast reference line, i.e. a furrow. The problem of tractor balancing on slopes has also been solved.

Keywords: tractor, optical system, driving automation, motion stability.

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A new «pulse evaporator-horizontal cylindric flame» atomizer for atomic-absorption spectrometry has been investigated. Unlike the «evaporator-flame-adapter» atomizer, the suggested device allows to increase sensitivity both for easily atomized and easily volatile and hardly atomized and hardly volatile elements, and to exclude the memory effect. The absorption signal dependence on the absorption zone length, the flame gases velocity, the angle between the beam and the flame gases direction, the distance between the beam and the source of atoms has been studied. The obtained results allow to select optimal constructive parameters of the atomizer.The gain in sensitivity with respect to the «lengthen evaporator – slit burner» atomizer which can reach an order has been estimated.

Keywords: atomic-absorption spectrometry, pulse evaporator, cylindric flame, absorption signal.

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A novel phase-frequency method for precision measurement of the delay time of a fiber optical light guide is proposed. Using the delay time of signals, the chromatic dispersion of the light guide can be defined. By this method it is possible to evaluate one of the principle characteristics of the light guides which can be used in contemporary high-speed telecommunication systems.

Keywords: fiberoptics, light guide, delay time, chromatic dispersion, frequency measurement.

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A polarization holographic method which allows us to reconstruct the polarization state of an object wavefront together with a phase, an amplitude and a frequency is described. The possible applications of the method in different tasks is discussed.

Keywords: holography, polarization, Veigert effect, optical memory, pseudoform.

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A model of the magnetosphere of the Earth, which helps to explain some processes occuring in the atmosphere of the planet, such as seasonal fluctuations of the ozone concentration, aurorae, etc., depending on the magnetosphere orientation to the solar wind and the phenomenon of magnetosphere self-regulation, is described.

Keywords: magnetosphere of the Earth, atmospheric ozone, aurorae, regulative properties.

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Using the approximation method of the failure distribution probability function, the analysis of the reliability of analog devices connected in parallel has been carried out. The index of the faultless operation time probability has been obtained.

Keywords: automated control systems, reliability, failure, functionability.

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Single crystals of the La_1-xNd_xMgAl₁₁O₁₉ systems were grown by the Bridgman -Stockbarger method from the melt (in the range of x=0.02 to 0,5) through vertically and horizontally directed crystallization. Experiments on resonance excitation of active elements have been carried out. The spectral-luminescent properties of the crystals have been studied. The Nd ions ⁴F_3/2 metastable state lifetimes have been measured for the crystals grown in different gaseous media. It is suggested to apply the crystals of lanthanum hexaaluminate in various laser devices.

Keywords: laser material, lanthanum hexaaluminate, technology

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Single-crystal scintillators (YAlO₃:Ce³⁺ and Y₃ Al₅ O₁₂ :Ce³⁺) intended for application in the detectors of nuclear radiation are studied. The single crystals of yttrium aluminium perovskite and yttrium aluminium garnet activated by trivalent cerium ions have been grown by the Bridgman-Stockbarger method from the melt through vertically-directed crystallization in the reducing atmosphere of Ar and H₂. Effective methods for changing the crystal growth conditions are examined.

Keywords: scintillator, crystal growth, yttrium aluminium perovskite, yttrium aluminium garnet.

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A method of keeping the big mass (>30g) of ultra-pure (7N) liquid gallium in the overcooled state at temperatures below the room temperature for an unilimitedly long time has been developed. Liquefied gallium encapsulated in the ultra-thin (<1000nm) elastic skin formed by photo-stimulated oxidation is protected from external crystallization centers. For its crystallization the overcooling down to -40^oC is necessary; at the same time, the meling temperature decreases to 13.6^oC, that is a new property of ultra-pure gallium. This fact can be explained by a polycluster (conglomerate) structure of liquefied gallium.

Keywords: liquation, gallium, structure, cluster.

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A new technological method of radical-beam epitaxy (RBE) is presented. This method enables us to obtain the samples of the II-VI wide-band-gap compounds with given electrical and optical properties. High monocrystal samples of ZnO have been obtained by the quasi-epitaxial method. The free A,B and C excitons radiation in photoluminescence spectra of the ZnO layers was observed.

Keywords: epitaxy, defect, exciton, photoluminescence.

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The classification of the electrophysical and radiative properties of the structures produced on the base of the ZnSe single crystals in oxygen radicals is reported. The mechanism of the current passage and the excitation of their electroluminescence were revealed. The external quantum efficiency of blue electroluminescence was found to be 10^-3 photon/electron or _{h ext} ~ 0.1%.

Keywords: single crystals, radical-beam epitaxy, injection, p-n junction, electroluminescence.

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On the basis of a new mechanism of atoms migration in condensed media, the technological photostimulated processes of doping and annealing have been developed. The preliminary results of application of these processes for producing the light-emitting diodes on GaAsAl and GaP and for deriving p-n junctions and diodes in the p-type monocrystal samples as 6НSiC are presented.

Keywords: optoelectronics, microelectronics, photostimulation, technology.

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It is shown that as a result of irradiation of accelerated electrons (E=3MeV) by relatively small doses (10¹²-10¹⁴ cm^-2) and subsequent annealing (T=Ј 520 K), considerable increase in the luminous intensity of factory-made emitting structures of red (GaAlAs< Zn> ), green (GaP< N> ) and yellow (GaP< N,Zn,O> ) luminescence takes place. The effect is explained by healing the І geneticІ defects of the growth of crystal structures which represent the centers of radiationless recombination with a large cross-section of scattering.

Keywords: radiation-thermal treatment, radiation-stimulated diffusion, healing of defects.

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It is shown that, with the help of pulse-photon treatment, in 6H-SiC implanted by B⁺ ions, it is possible to perform annealing of radiative defects. Thus, it is possible to decrease the heating temperature of samples by 600-1000 degrees in comparison with traditional thermal annealing (Т=1700 - 2100 К). A considerable role of the ionization factor in the process of photon annealing of the radiative defects is shown.

Keywords: ion implantation, pulse-photon annealing, silicon carbide.

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A new method of obtaining the set axial/radial gradient of the refractive index in a polymeric medium, which is based on changing the optical properties by g -irradiation, is described. The method has been tried out on an isotactic polypropylene thin film and can be easily applied to other polymers with consideration of their resistance to radiation.

Keywords: gradient, refractive index, polymers, g -irradiation, method of obtaining.

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A process of nonradiative transfer of the electron-beam excitation energy (NTE) between the Pr³⁺ and Nd³⁺ ions in silicate glass has been detected. As the result of that process, there was observed cooperative sensitization of the Nd³⁺ luminescence by the Pr³⁺ ions at transition ⁴Fe_3/2 ® ⁴J1_3/2, which was excited by continiuous radiation of the YAG laser; the Nd³⁺ power was 88 mV at the wave-length of l = 1.064 m m in the Pr³⁺ ion absorption band at transition ³H_4® ¹G₄. The mechanism of the NTE responsible for the Nd³⁺ ion luminescence in the band with the peak at l = 1.34 m m is considered.

Keywords: silicate glass, cooperative sensitization, Nd³⁺ ion luminescence, Pr³⁺ ions.

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New investigations of the electrooptic effect in a liquid-crystal "amorphous" cholesteric structure have been carried out. It is shown that the structure can operate without polymer - oriented covers and without any treatment of the surface. In this case, considerably lower operating voltages have been obtained.

Keywords: liquid crystals, electrooptic effect.

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On the basis of GaAs and AlGaAs, the p-n-i-n⁺ structure was obtained by liquid-phase epitaxy. Basing on the mentioned structure, a memory matrix with optical indication of the recorded data was fabricated with the help of planar technology. Both optic and electric channels can be used for data recording, that significantly expands functional possibilities of a new device (the memory matrix).

Keywords: memory matrix, liquid-phase epitaxy, optical indication, data recording.

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Zn diffusion in GaAs from the zinc-silicate glass (ZSG) was investigated. The ZSG film was deposited onto the GaAs sample at a low (~ 100^OC) temperature by reactive ion-plasma sputtering. It was established that during the heat treatment, the ZSG film served as a protective layer and simultaneously provided Zn atoms for doping GaAs and producing the p-type layer. As compared with ion implantation, our method simplifies the Zn diffusion process in GaAs providing formation of a shallow diffusion layer (< 1 m ) with a sharp p-n junction. The developed technology can be successfully used for fabrication of micro- and optoelectronic devices and ICs on the III-V compound semiconductors.

Keywords: diffusion, GaAs, Zn, pulse photon annealing.

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Ultra-pure arsenic, aluminium nitride and gallium nitride developed and produced in Sukhumi Institute of Physics and Technology are described. The possibilities of their application in thermo-, micro- and optoelectronics are considered. The basic properties of the materials and the methods of their production are presented.

Keywords: ultra-pure arsenic, gallium nitride, micro- and optoelectronics, thermal emission, synthesis.

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An UHF klystron amplifier designed in I.Vekua Sukhumi Physical and Technical Institute is considered. By means of this installation it is possible to produce electromagnetic radiation with power of 350 MW and the frequency f = 3 · 10⁹ Hz. The installation units and their basic parameters are described. The klystron amplifier is designed on the basis of a quasi-stationary toroidal volume resonator. Electron flow, the parameters of which are I₀ = 500 A, V = 10⁶ V, is formed by an accelerator of the quarter-wavelength resonator of high frequency. Efficiency of the installation is η = 75%.

Keywords: UHF energy, non-traditional method of energy generation, resonator accelerator, klystron amplifier.

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The design of a high-efficient planar magnetronic spraying device in vacuum for production of thin-film coatings is presented. The prospects of its application in various industries, including the production of optoelectronic devices, are considered.

Keywords: thin-film coatings, target, cathode unit, spraying

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The results of experimental investigations are presented. The purpose of the experiments was improvement of the technology of manufacturing the quartz and glass plates for liquid crystal displays of optical converters. The analysis of the results has shown that the developed technology satisfies modern requirements of manufacturing the quartz/glass plates. It is shown that, by adjusting the parameters of processing, it is possible to control the process of manufacturing. The obtained experimental data are within the framework of the theoretical predictions.

Keywords: LC screens, polishing, roughness.

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Semiconductor sign-synthesizing microdevices, so-called scale indicators, of various dimensions used for analog information display are described. The methods of information representation are considered.

Keywords: semiconductor, sign-synthesizing microdevices, scale indicator.

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In the span of 2-47m m in the spectra of optical crystals InP and InAs there is one peak, of solid solutions of InP _xInAs_1-x there are two peaks with coefficient of reflection 40%-80%. In the long-wave area of the spectrum a set of mirrors made of semiconductor InPAs alloys can be used to avoid light scattering.

Keywords: reflection, solid solutions, monochromator.

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The high efficiency devices of individual and common use for monitoring of explosive and poisoning gases in mines have been developed and prepared for introduction. The optical principle of the device has been developed and an emitter and a receiver on the basis of solid solutions InP and InAs-GaAs have been produced.

Keywords: semiconductor devices, monitoring, mining, explosive gases.

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Monolithic scale indicators based on the heterostructures p⁺GaAs - pGa_1-xAl_xAs - nG_1-yAl_yAs (x=0.33 - 0.35; y=0.37 - 0.40) grown by liquid epitaxy were produced and investigated. There were developed structures and isoplanar technology for fabrication of monolithic light-emitting crystals for ten-element scale indicators, which differ from each other by the size of emitting elements and the step between the elements. Principal electophysical parameters of the developed indicators are presented.

Keywords: monolithic indicator, red luminescence, multielement scale, heterostucture, technology.

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A design of the solar energy semiconductor converter based on Si and the GaAlAs compounds with the use of the multifunctional In₂O₃ layers is offered. The design provides for maximum simplification of the fabrication process, which does not require expensive and labour-consuming equipment that reduces the production cost. The work is directed to realization of the offered design in practice.

Keywords: semiconductor converter, solar energy, transmitting layer, design, technology.

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A design and a principle of operation of the device for measuring the intensity and the dose of ultraviolet radiation are described. Applications of the offered intensitometer are considered. The spectral characteristics of the sensor employed, the block diagram and the specifications of the intensitometer are presented.

Keywords: ultraviolet radiation, intensitometer, design.

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Some problems of designing the sensor of the gas-vapor mixture reagents concentration are considered. A new design of the sensor, in which a thin-film thermal resistor of the metal-polymer structure is used as a sensing element, is described. The results of investigation of metrological chararteristics of the sensor are presented.

Keywords: thermoconductometric sensor, metal-polymer thermal resistor, sensing element.

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Two types of Infrared-to-Visible image liquid-crystal converters are proposed. The first of them is based on the MIS-LC (Metal-Insulator-Semiconductor-Liquid Crystal) structure, in which the problem of match of a low-ohmic semiconductor with a high-ohmic liquid crystal has been solved. The device is a low-voltage analog of the electronic-optical image converters used in night viewing devices. The second type of the presented image converters is based on thermooptical properties of liquid crystals. It is a nonselective visualizer of thermal fields, in which, for the first time, a threshold thermooptical effect in the liquid crystals is used. In both types of the image converters, the sensitivity of 10^-8W/cm² has been achieved.

Keywords: liquid crystals, night viewing devices, thermovisualizers.

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The fiber-optic refractometer fabricated as a probe, an optical head of which is a glass cylinder, at the bottom of which there is a reflecting mirror layer and to the conic top of which a light source and a photodetector are attached via the crossed polarizer and analyzer, has been developed.

Keywords: refractometer, fiber-optics, refractive index.

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A new type of an adaptive antenna for portable cellular handsets is offered. It's electromagnetic properties have been investigated. Practical recmmendations on antenna designing are made. The offered model reduces the amount of energy absorbed by a user, significantly improves the radiation efficiency, and consumes minimum power.

Keywords: adaptive atenna, cellular communication.

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The new generation spectrophotometer, that allows to research optical characteristics both of single-scattering and multiple-scattering media was designed by Prof. J. Beridze [1]. The operation principle of the spectrophotometer is based on the theory of optics of a light-scattering channel worked out by the author. Alternatively to traditional spectrophotometers, the offered spectrophotometer allows to research optical characteristics of multiple-scattering media (index of extinction of multiple scattering h, indexes of scattering s and absorption a , index of transport scattering s _t, asymmetry factor < cosq > ).

Keywords: spectrophotometer, multiple scattering, index of extinction.

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