Yerevan, Armenia

The State Engineering University of Armenia is a technical university located in Yerevan, Armenia. Established as the Yerevan Polytechnic Institute in 1933, it provides educational and research programs in various fields of technology and science related to engineering. Currently there are more than 10,000 students and more than 900 faculty members. Wikipedia.


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Abrahamian R.M.,State Engineering University of Armenia
Journal of Contemporary Physics | Year: 2010

It is shown that the efficiency of a regenerative Stirling cycle can principally not reach that of a Carnot cycle operating in the same temperature range. A relation is obtained between the degree of regeneration and the characteristics of regenerator. The maximum efficiency of an ideal regenerative Stirling engine is obtained. © 2010 Allerton Press, Inc.


Mkoyan R.S.,State Engineering University of Armenia
Izvestiya Vysshikh Uchebnykh Zavedenii, Seriya Teknologiya Tekstil'noi Promyshlennosti | Year: 2016

Designed for installation after each operation finishes assess the quality of samples of hosiery. For the operation of the WTO as the decisive qualitative indicator of the selected density of the weave, for the operation of dyeing, the fastness to wet friction and impact for the operation of the forming - degree of creasing. Obtained quality parameters were compared with those of products of LLC "Lentex", Gyumri, Armenia, as well as with existing standards. It was found that the samples of hosiery waste at the installation developed quality indicators better than the same indicators of factory samples.


Vorobiev A.,Chalmers University of Technology | Gevorgian S.,Chalmers University of Technology | Martirosyan N.,State Engineering University of Armenia | Loffler M.,Chalmers University of Technology | Olsson E.,Chalmers University of Technology
Applied Physics Letters | Year: 2012

Intrinsically tunable 0.67BiFeO3-0.33BaTiO3 (BF-BT) thin film bulk acoustic wave resonators with record high tunability of 4.4 and effective electromechanical coupling coefficient of 10 are fabricated and analyzed. The analysis, based on the theory of the dc field induced piezoelectric effect with the mechanical loading by the electrodes taken into account, reveals that the enhanced parameters are associated with the inherently high BF-BT electrostriction coefficient, which is found to be 5.9 × 1010 m/F. The Q-factor of the BF-BT resonators is up to 220 at 4.1 GHz and is limited mainly by acoustic wave scattering at reflection from a relatively rough top interface. © 2012 American Institute of Physics.


Aharonyan K.H.,State Engineering University of Armenia
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

The spatial and time dependencies of the dielectric function for the quasi-two dimensional (Q2D) electron gas (EG) in a finite confining potential quantum well (QW) are calculated by using a self-consistent approach (SQF). Taking into account the influences of mismatch of strong discontinuous dielectric constant and effective masse across the interfaces the dielectric response function analytic expressions are derived for a rectangular finite potential barrier QW for the first time. The deviations from the results when these mismatches are absent are established. By using exactly calculated dielectric function a comparison with the respective asymptotic expressions of finite and infinite confining models is presented both analytically and numerically on the base of realistic EuS/PbS/EuS QW. The transition interval between 2D and 3D cases has been demonstrated numerically. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Aharonyan K.H.,State Engineering University of Armenia
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2011

A model for investigation of impurity states in realistic EuS/PbS/EuS finite confining potential quantum well (QW) is theoretically developed. A strong contrast of available material parameters across the QW interfaces and the characteristic band-nonparabolicity effect of lead salt semiconductor are taken into account while using a variational approach. In the presence of medium polarization a quasi two-dimensional (Q2D) Coulomb form factor analysis is carried out. Initial deviations from the infinite confining model results are established. An impurity binding energy problem has been investigated and for the first time an explicit analytical expression in the limit of very thin QW is derived. With decreasing finite confining potential QW width a monotonic increase of the binding energy is seen for quite small values of width. For realistic nanostructures a comparison of strongly enhanced donor and acceptor binding energies is presented. © 2011 Elsevier B.V. All rights reserved.


Harutyunyana V.A.,State Engineering University of Armenia
Journal of Applied Physics | Year: 2011

The states of interacting electron-hole pair in semiconductor nanotube in the presence of strong lateral homogeneous electric field are considered theoretically. It is shown in single-particle approximation that along with the size-quantization of charge carriers' motion by the radial direction the external strong field leads to the additional (field) localization of particles by the angular variable also. The corresponding additional energy spectrum has an equidistance character. At the same time the strong external field polarizes the electron-hole pair and traps them on the opposite ends of tube's diameter. Consequently, the excitonic complex with transversal dimensions of the order of the system's diameter is formed in a nanotube. By using the variation approach, the binding energies and wave functions of first two states of such field excitonlike complex in the tube are also calculated. The electro-optical transitions in the tube without and with the account of electron-hole interaction are considered. It is shown that along with the dependence on the geometric dimensions of the sample and the intensity of the external field, the presence of strong electric field leads also to an explicit dependence of the intensity and the threshold frequencies of absorption on the effective mass of carriers. The resulting field dependence of the optical characteristics of the system can serve as a basis for the direct experimental observation of such excitonlike complexes in semiconductor nanotubes. © 2011 American Institute of Physics.


Harutyunyan V.A.,State Engineering University of Armenia
Physics of the Solid State | Year: 2010

The single-electron states in a quantized cylindrical layer in the presence of a strong homogeneous electric field have been considered in the isotropic effective mass approximation. The energy spectrum and the envelope wave functions of charge carriers in the layer have been obtained in the explicit form. It has been shown that a strong external electric field leads to an additional localization of carriers in their angular motion. The corresponding selection rules have been derived, and the absorption band of intraband-intersubband optical transitions in the layer has been calculated. © 2010 Pleiades Publishing, Ltd.


Aharonyan K.H.,State Engineering University of Armenia
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2010

In the framework of two-band envelope-function formalism the binding energy and ground state radius of an exciton in a EuS/PbS/EuS finite confining potential quantum well (QW) are calculated analytically by using a variational approach. By taking into account the effective masses mismatch across the interfaces and anisotropic carrier masses in the QW, the initial deviation from the result of an infinite confining potential QW is derived. The influence of strong discontinuous dielectric constants and nonparabolic mirror bands is fully evaluated by using the coupling between QW longitudinal and transversal carrier motions. The correlations of the quantum, dielectric, barrier mass and nonparabolicity effects in the exciton binding energy are determined. A comparison with the respective quantities of two confining models is presented. © 2010 Elsevier B.V.


Aharonyan K.H.,State Engineering University of Armenia
Journal of Physics: Conference Series | Year: 2012

The model to investigate the screened Coulomb interaction in realistic EuS/PbS/EuS finite confining potential quantum well is theoretically developed. A strong contrast of existing material parameters across the well interfaces and typical band-nonparabolicity effect of lead salt semiconductor are taken into account while a variational approach has been used. In presence of inhomogeneous dielectric polarization a quasi two-dimensional screened Coulomb form factor analysis is carried out by using random phase approximation. Initial deviations from the inhomogeneous polarization absent case are established and in particular quantum well width dependent screened logarithmical-type interaction potential is obtained. A screened binding energy has been investigated and an explicit logarithmical-type expression is used for the first time. Depending on the realistic nanostructure specifics a monotonic decrease of the enhanced binding energy is received when in-plane carrier density /temperature ratio parameter increases.


Harutyunyan V.A.,State Engineering University of Armenia
Physics of the Solid State | Year: 2012

The single-electron states in a quantized cylindrical layer have been considered in the presence of a moderate homogeneous electric field, when the energy imparted to a charge carrier by the electric field becomes comparable to the energy of rotational motion of this particle. The corresponding energy spectrum and the envelopes of the wave functions of charge carriers in the layer have been obtained in an explicit form. The electro-optical absorption band of a weak electromagnetic wave has been calculated. It has been found that the absorption intensity increases with an increase in the intensity of the electric field. The external electric field leads to an explicit dependence of the absorption intensity on the effective masses of charge carriers. The absorption intensity decreases as the difference between the effective masses of charge carriers increases. There is also an effective broadening of the band gap, which is determined by the geometrical dimensions of the sample and the magnitude of the external field. © 2012 Pleiades Publishing, Ltd.

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