1. DESTRUCTION OF PULSE TRAINS IN WEAKLY NONLINEAR OSCILLATOR
chaos, dynamical systems, train pulses, Quasi linear oscillator
Vestnik KhNU №756 Pages. 71-78
A study has been carried out on the transition of train of pulses via a weakly nonlinear oscillator. Conditions of destruction of such trains as a result of appearance of chaotic instabilities have been analyzed. Analytically conditions of the appearance of chaotic instabilities have been determined by using the method of secondary averaging.
2. AlN/AlxGa1-xN resonance tunnell diodes
D.V. Pavlenko, E.D. Prokhorov
nitrides, Quantum well, NDC, oscillation efficiency.
Vestnik KhNU №756 Pages. 105-108
Double and threefold compounds of nitrides AIN/AIGaN resonance tunnel diodes using height of barriers are concedered. In the quantum well of diodes there are a plenty energy levels. Electron energy levels in quantum well with variable structure of interconnections AlGaN are determined. The current - voltage characteristics of resonance - tunnel diodes with number of levels in a quantum wall up to five has been calculated. The RTD can have up to five sites with negative differential conductance are demonstrated. The possible RTD oscillation efficiency on all sites of negative differential conductivity at difference barriers and quantum well's material are determined.
3. CALCULATION and EXPERIMENTAL MEASUREMENT OF ANODE BLOCKS PARAMETERS OF MAGNETRONS
K.M. Basrawi, G.I. Churyumov
magnetron, anode block, Q quality factor, loaded Q factor, equivalent capacity, mode
Vestnik KhNU №756 Pages. 132-138
In this paper the outcomes of calculation and experimental measurements of cold parameters of the pulse and continuous X - range magnetrons are presented. The measuring and calculation techniques of equivalent capacities of the anode blocks of the magnetrons as well as Q quality factor, loaded Q factor and external Q factors of the resonant system for main N/2 - mode and nearest N/2 -1 and N/2 -2 -modes is given
4. QUEST AND CREATION OF NOVEL ACTIVE MEDIA FOR DYE LASERS IN IRE NAS OF UKRAINE
laser dye, molecular structure, spectrum, fluorescence, Quantum yield, lasing efficiency, photostability
Vestnik KhNU №806 Pages. 92-98
Numerous studies of novel active media for dye lasers fulfilled in IRE NAS of Ukraine are generalized in present review. Peculiarities of spectral, fluorescence and lasing characteristics of some laser dye classes for visible region of the spectrum have been analysed. A special attention is focused upon effects of structure of the dye molecule and its solvent environment on these characteristics. The outlook of development for dye-doped active media has been discussed
resonant photodiode, Quantum efficiency, modulation characteristic, transfer matrix method.
Vestnik KhNU №983 Pages. 54-66
In this paper, we have described methods of modeling of resonant cavity photodiods based on semiconductor quantum dimensional structures for ultrashort connections. The problem of misalignment of operating wavelength of emmiter and receiver has been shown and quantum efficiency maxima spectral shift temperature dependence was analysed. Technological control of layer thickness using laser interferometer with 1 atomic layer quality control was shown. Comparative analysis made in this paper of modulation characteristic of regular and resonant cavity detectors shows more than 5 times increasing quantum efficiency and modulation band product in resonant detector case.
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