37 research outputs found
Modern geography teacher: training requirements
The personality of a geography teacher must be considered as internal integrity, when professional and personal values are closely related to the system of universal values. The teacher, throughout his professional activity, assimilates the necessary knowledge, acquires skills in a personal context. A geography teacher should always be interesting for students, create in the school that spiritual atmosphere, thanks to which children will have a desire for knowledge
Formation of initial data when planning for custom manufacturing
The formulation of the problem of production planning for custom small-scale electronic production is considered. In order to increase the efficiency of solving automation planning problems, an approach has been developed to generate optimal initial data for planning, taking into account their dimensionality. An improvement in the execution time of production plans at the first stage of manufacturing an order by an average of 5-10% is shown
Determination of sign during phase correction of sign-variable modulation spectra of intersubband light absorption in GaAs/AlGaAs quantum wells
Plasmon phonon modes and optical resonances in n-GaN
We study theoretically and experimentally transverse and longitudinal electromagnetic waves in n-GaN epitaxial layers. The studies are carried out on the epitaxial layers with various doping levels. Simulation of the reflectivity and absorptivity spectra is performed in a wide frequency range. Additionally, the radiation emission spectra are simulated for various temperatures of the GaN epitaxial layer. It is shown that the resonance peculiarities of the optical spectra are located closely to the frequencies of the coupled plasmon phonon modes. Experimental studies of the reflectivity spectra have been performed in the spectral range 2-20 THz. The experimental spectra are well fitted by the simulated ones and can be used for contactless determination of the electron concentration and mobility in GaN epitaxial layers. The experimental and theoretical results of the present work provide insights for the development of GaN-based devices aimed to absorb/emit terahertz or mid infrared radiation selectively.Peer reviewe
2D electrons and 2D plasmons in AlGaN/GaN nanostructure under highly non-equilibrium conditions
We report on studies of electrically excited non-equilibrium 2D electrons and 2D plasmons in an AlGaN/GaN nanostructure. Optical access to 2D plasmons is provided by means of a metal grating fabricated at the nanostructure surface, while the properties of 2D electrons are examined in the samples without metal grating. The paper focuses on the creation of highly non-equilibrium conditions when the effective temperature of 2D electrons is much higher than the crystal lattice temperature. Such conditions are realized by applying short electrical pulses with a low repetition frequency. A method has been developed for independently determining the temperature of hot electrons and the temperature of the crystal lattice under an applied electric field. It has been shown that under highly non-equilibrium conditions the spectral density of terahertz electroluminescence of 2D plasmons can significantly exceed that of 2D electrons at a certain frequency.Peer reviewe