National University of Architecture and Construction of Armenia

Yerevan, Armenia

National University of Architecture and Construction of Armenia

Yerevan, Armenia
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Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia | Kirakosyan A.A.,Yerevan State University | Laroze D.,University of Tarapacá
Optics Communications | Year: 2017

The intraband optical absorption have been investigated in the presence of hydrogenic donor impurity in GaAs/GaAlAs quantum dot and quantum ring in the intense laser field. The single electron energy spectrum and wave functions have been found using the effective mass approximation and exact diagonalization technique. Different selection rules are obtained for intraband transitions depending on the direction of incident light polarization. Due to the accidental degeneracy of the laser dressed impurity states the crossings of the curves of the threshold energies and the dipole matrix elements on laser field parameter have been observed. The intraband absorption coefficient is calculated for different locations of hydrogenic donor impurity and different values of intense laser field parameter. The obtained results show that the absorption spectrum can exhibit either a blue- or redshift depending on the impurity location, values of the laser field parameter and direction of incident light polarization. The obtained theoretical results indicate a novel opportunity to tune the performance of new devices, based on the quantum dots and quantum rings and to control their specific properties by means of intense laser and hydrogenic donor impurity. © 2016 Elsevier B.V.


Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
European Physical Journal Plus | Year: 2016

The simultaneous influence of hydrostatic pressure and intense laser field on hydrogenic donor impurity states and intraband optical absorption has been investigated in GaAs/Ga 1 - x˜Al x˜As quantum ring. The one-electron energy spectrum and wave functions have been found using the effective mass approximation and exact diagonalization technique. The intraband absorption coefficient is calculated for different values of the hydrostatic pressure, intense laser field parameter and different locations of hydrogenic donor impurity. The simultaneous influence of hydrostatic pressure and intense laser field shows that while the increment of the first one leads only to the blueshift of the absorption spectrum, the augmentation of the second one makes the redshift. In addition, both blueshift and redshift of the spectrum have been obtained with the changes of impurity location. The obtained theoretical results indicate good controlling means of the optical spectrum of ring-like structures by the combined influence of the considered factors. © 2016, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg.


Mkhitaryan S.M.,Armenian National Academy of Sciences | Mkrtchyan M.S.,Armenian National Academy of Sciences | Kanetsyan E.G.,National University of Architecture and Construction of Armenia
ZAMM Zeitschrift fur Angewandte Mathematik und Mechanik | Year: 2017

In the present paper, using the ideas of the well-known method for solving singular integral equations (SIE), based on Gaussian quadrature formulas for ordinary integrals and singular integral with Cauchy kernel, a somewhat different approach is proposed for solving the Prandtl integro-differential equation (IDE). This approach in accordance with a polynomial method includes different approximation methods for a continuous component of Prandtl's IDE solution, namely an approximation in the form of Bernstein's polynomials, Chebyshev's polynomials of the first kind and approximation in the form of Lagrange interpolation polynomial at the Chebyshev knots. As a result, the Prandtl IDE is reduced to the system of linear algebraic equations (SLAE) of the rather simple structure. These different approximation methods will be illustrated by the example of the problem on contact interaction between a stringer of finite length, having a variable along the length rigidity in tension-compression or a variable cross-section, and an elastic semi-infinite plate. This interaction is described by the Prandtl IDE. The comparative numerical analysis of the results obtained by different methods is carried out. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Hakobyan S.N.,State Engineering University of Armenia | Shahinyan M.A.,Yerevan State University | Babayan Y.S.,National University of Architecture and Construction of Armenia
Biophysical Reviews and Letters | Year: 2016

In the present work, the thermostabilities of mitoxantrone (MTX) complexes with DNA from sarcoma 45 and healthy rat liver were studied. DNAs from both sources were irradiated by resonant (64.5 GHz and 50.3 GHz) and nonresonant (48.3 GHz) frequencies of water. The obtained data showed that DNA solution irradiation by resonant frequencies of water induces a dehydration of nucleotides and Na(Formula presented.) ions in the solution. It is shown that at relatively low concentrations of MTX, when one MTX molecule binds to almost 100 pairs of bases of DNA, the thermostabilities of complexes decrease. Moreover, this change is more pronounced ((Formula presented.)C) at the complex formation with DNA released from sarcoma 45 tumor. © 2016 World Scientific Publishing Company


Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2015

A detailed investigation of the lateral electric field effect on single electron states in coupled quantum dot-ring structure has been systematically studied for cases with and without an on-center hydrogenic donor impurity. The single electron energy spectrum has been found using the effective mass approximation and an exact diagonalization technique. The electron ground state's probability density has been examined for different values of the confinement energies and depth of dot confinement relative to the bottom of the quantum ring and barrier thickness. The energy level's dependence on the electric field strength has been studied considering the effects of mentioned parameters of the structure and hydrogenic donor impurity. © 2015 Elsevier B.V. All rights reserved.


Laroze D.,University of Tarapacá | Barseghyan M.,Yerevan State University | Barseghyan M.,National University of Architecture and Construction of Armenia | Radu A.,Polytechnic University of Bucharest | Kirakosyan A.A.,Yerevan State University
Physica B: Condensed Matter | Year: 2016

The hydrogenic donor impurity states in two-dimensional GaAs/Ga0.7Al0.3As quantum dot and quantum ring have been investigated under the action of intense laser field. A laser dressed effect on both electron confining and electron-impurity Coulomb interaction potentials has been considered. The single electron energy spectrum and wave functions have been found using the effective mass approximation and exact diagonalization technique. The accidental degeneracy of the impurity states have been observed for different positions of the impurity and versus values of the laser field parameter. The obtained theoretical results indicate a novel opportunity to tune the performance of quantum dots and quantum rings and to control their specific properties by means of laser field. © 2016 Elsevier B.V.


Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
Chemical Physics | Year: 2016

The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed. © 2016 Elsevier B.V.


Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
Optics Communications | Year: 2016

The intraband optical absorption in GaAs/Ga0.7Al0.3As two-dimensional single quantum ring is investigated. Considering the combined effects of hydrostatic pressure and intense laser field the energy of the ground and few excited states has been found using the effective mass approximation and exact diagonalization technique. The energies of these states and the corresponding threshold energy of the intraband optical transitions are examined as a function of hydrostatic pressure for the different values of the laser field parameter. We also investigated the dependencies of the intraband optical absorption coefficient as a function of incident photon energy for different values of hydrostatic pressure and laser field parameter. It is found that the effects of hydrostatic pressure and intense laser field lead to redshift and blueshift of the intraband optical spectrum respectively. © 2016 Elsevier B.V.


Mamyan Z.,National University of Architecture and Construction of Armenia | Aloyan A.,National University of Architecture and Construction of Armenia | Kartashyan T.,National University of Architecture and Construction of Armenia
MATEC Web of Conferences | Year: 2016

In this article the role of public open spaces in Yerevan city as well as their correct and literate organisation from an architectural and planning perspective are studied and evaluated. In recent years a special attention has been paid to the development of Yerevan, the capital as well as other historical cities of Armenia in order to contribute to tourism development. This aspect resulted in the creation of new urban and architectural requirements. Among other issues the organisation of architectural environment of public open spaces - the role of urban design in our reality are also characterized. In these conditions urban and architectural organisation of public open spaces in historical cities are very important. Thus, the present study not only emphasizes the importance of studying the evolution of open spaces in Yerevan, but also stresses the significance of implementation of the international practice in this field in the city of Yerevan. The complex analyses, coordination and developing conditions of nowadays and historical requirements of historical cities are provided. The urban organisation and appropriate method selection for the current requirements of public open spaces are going to be analysed. © 2016 The Authors, published by EDP Sciences.


Tovmasyan S.,National University of Architecture and Construction of Armenia
ZFV - Zeitschrift fur Geodasie, Geoinformation und Landmanagement | Year: 2015

This paper contains general description of the present status of spatial planning in the Republic of Armenia and the Federal Republic of Germany. Similarities and differences between two functioning models in the above-mentioned countries are analyzed. As a result of the analysis, proposals on possibilities of application of some elements of the German model in Armenia are submitted. © 2015, Wissner Verlag. All rights reserved.

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