Microwave induced magnetoresistance oscillations at the subharmonics of the cyclotron resonance

The magnetoresistance oscillations, which occur in a two-dimensional electron system exposed to strong microwave radiation when the microwave frequency $\omega$ coincides with the n-th subharmonic of the cyclotron frequency $\omega_c$ have been investigated for n = 2, 3 and 4. It is shown that these subharmonic features can be explained within a non-equilibrium energy distribution function picture without invoking multi-photon absorption processes. The existence of a frequency threshold above which such oscillations disappear lends further support to this explanation.Comment: 5 pages, 5 figure

Microwave photoresponse in the 2D electron system caused by intra-Landau level transitions

The influence of microwave radiation on the DC-magnetoresistance of 2D-electrons is studied in the regime beyond the recently discovered zero resistance states when the cyclotron frequency exceeds the radiation frequency. Radiation below 30 GHz causes a strong suppression of the resistance over a wide magnetic field range, whereas higher frequencies produce a non-monotonic behavior in the damping of the Shubnikov-de Haas oscillations. These observations are explained by the creation of a non-equilibrium electron distribution function by microwave induced intra-Landau level transitions.Comment: 4 pages, 5 figure

Application of planetary ball mill for manufacturing of shielding composite coatings based on polyester powder paints and carbon fillers

Blend polyester powder paint and particulate carbon filler in the form of colloidal graphite and the carbon black product were investigated. Powder paint and carbon materials were treated together in a planetary ball mill. The data of the structural analysis and transmission coefficients of electromagnetic waves of terahertz range through the flat shape samples are presented

Использование результатов этнолингвистических исследований в преподавании русского языка как иностранного (на материале лексики воспитания в русском и таджикском языках)

The article is devoted to the use of the results of linguistic researches of Russian lexical material in the practice of teaching Russian as a foreign or non-native language when training Russian language teachers for national schools. It is argued that accumulated and stored ethno-cultural information in the language units may be the subject of comparative study when learning the non-native language. The didactic potential of linguistic methods is estimated, namely semantic and motivational analysis of words or collocations in different languages, one native, the other learning. The comparison of lexis of the “Education” thematic group in Tajik and Russian languages is made in the context of the search of the material for training Tajik students who plan to become teachers the methods of teaching Russian as a foreign language. © 2016, Slovenska Vzdelavacia Obstaravacia. All rights reserved.Статья посвящена вопросам использования результатов лингвистических исследований русского лексического материала в практике преподавания русского языка как иностранного или неродного при подготовке учителей русского языка для национальных школ. Утверждается, что накопленная и сохраненная в языковых единицах этнокультурная информация может стать предметом сопоставительного изучения при освоении неродного языка. Оценивается дидактический потенциал лингвистических методов, заключающихся в семантическом и мотивационном анализе слов или фразеологических сочетаний из разных языков, один из которых родной, другой – осваиваемый. В контексте поиска материала для обучения таджикских студентов, которые в будущем планируют стать учителями, методике преподавания русского языка как неродного проводится сравнение лексики тематической группы «Воспитание» в таджикском и русском языках

Giant Magnetoresistance Oscillations Induced by Microwave Radiation and a Zero-Resistance State in a 2D Electron System with a Moderate Mobility

The effect of a microwave field in the frequency range from 54 to 140 $\mathrm{GHz}$ on the magnetotransport in a GaAs quantum well with AlAs/GaAs superlattice barriers and with an electron mobility no higher than $10^6$ $\mathrm{cm^2/Vs}$ is investigated. In the given two-dimensional system under the effect of microwave radiation, giant resistance oscillations are observed with their positions in magnetic field being determined by the ratio of the radiation frequency to the cyclotron frequency. Earlier, such oscillations had only been observed in GaAs/AlGaAs heterostructures with much higher mobilities. When the samples under study are irradiated with a 140-$\mathrm{GHz}$ microwave field, the resistance corresponding to the main oscillation minimum, which occurs near the cyclotron resonance, appears to be close to zero. The results of the study suggest that a mobility value lower than $10^6$ $\mathrm{cm^2/Vs}$ does not prevent the formation of zero-resistance states in magnetic field in a two-dimensional system under the effect of microwave radiation.Comment: 4 pages, 2 figur

Circular polarization dependent study of the microwave photoconductivity in a two-dimensional electron system

The polarization dependence of the low field microwave photoconductivity and absorption of a two-dimensional electron system has been investigated in a quasi-optical setup in which linear and any circular polarization can be produced in-situ. The microwave induced resistance oscillations and the zero resistance regions are notedly immune to the sense of circular polarization. This observation is discrepant with a number of proposed theories. Deviations only occur near the cyclotron resonance absorption where an unprecedented large resistance response is observed.Comment: 5 pages, 3 figure

Fractional quantum Hall effect without energy gap

In the fractional quantum Hall effect regime we measure diagonal ($\rho_{xx}$) and Hall ($\rho_{xy}$) magnetoresistivity tensor components of two-dimensional electron system (2DES) in gated GaAs/Al$_{x}$Ga$_{1-x}$As heterojunctions, together with capacitance between 2DES and the gate. We observe 1/3- and 2/3-fractional quantum Hall effect at rather low magnetic fields where corresponding fractional minima in the thermodynamical density of states have already disappeared manifesting complete suppression of the quasiparticle energy gaps.Comment: 4 pages, 4 figure

Spiritual and moral foundations of craft profession training

The relevance of the problem under consideration stemmed from the need of revival of craft education system in Russia which focuses on training personnel for small handicraft enterprises, and it is also very important to identify, to preserve and to adapt it to the modern realities of pedagogical experience which was gained by the vocational education system in the past. The purpose of the article is to substantiate the need for development of spiritual, moral, organizational and pedagogical foundations of craft vocational education development in Russia theoretically and methodologically. The central approach to the investigation of this problem is the study and generalization of pedagogical experience which makes it possible to substantiate the tendencies of formation of a new type of vocational education in Russia. The result of the study was the substantiation of the key qualities of a master craftsman as a creative thinker and craft labour as a man-making system of knowledge and practical experience forming “multidimensional human integrity”. The statement that modern craft education should take into account the productive and transforming essence of a person as fully as possible, and thus, it should be acmeologically oriented can be considered the key conclusion. The materials of the article can be useful to practitioners and vocational education scientists, teachers and postgraduate students who are interested in the development of teaching system and personnel training system. © 2018 by the authors

Electromagnetic response of the three-layer construction on the basis of barium hexaferrite and a foam glass

This paper contains results of study of the frequency dependence of reflection coefficient of the ceramic surface coated with the construction consisting of following layers: metal, composite on the basis of ferrite with hexagonal structure, and foam glass. It is shown that foam glass layer reduces significantly the reflecting characteristics of the construction