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Chisinau, Moldova

Harutyunyan V.A.,Slavonic University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2014

With the use of WKB (Wentzel-Kramers-Brillouin) method the quantum-mechanical problem of single-particle states in semiconductor quantized cylindrical and spherical layers is solved. Explicit analytical dependences of the energy spectrum and wave functions of charge carriers on geometrical sizes of the system and quantum numbers of radial and orbital movements of the particles are obtained. The results of analytical solution are compared with the results of numerical calculations. The results obtained are used to calculate coefficients of interband optical absorption in cylindrical and spherical heterolayers. © 2013 Elsevier B.V.

Harutyunyan V.A.,Slavonic University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2014

The single-particle states in a cylindrical nanotube placed in the field of charged ring are considered theoretically in the effective-mass approximation. The electrostatic field of charged ring creates an additional quantum well the symmetry axes of system. It is shown, that this quantum well can be described as one-dimensional modified Coulomb-like potential By using a variation-method the wave functions and energy levels of the first two states of charge carriers in the well were obtained. The interband and intraband electro-optical transitions in the tube are also considered. © 2013 Elsevier B.V.

Sultanalieva R.B.,Slavonic University | Mamutova S.,Endocrinology Dispensary | Van Der Haar F.,Emory University
Public Health Nutrition | Year: 2010

Objective Although goitre and cretinism were brought under control in Kyrgyzstan during the 1960s by centrally directed iodized salt supplies, iodine-deficiency disorders (IDD) had made a comeback when the USSR broke up in 1991. Upon independence, Kyrgyzstan started developing its own salt processing industry and by 2001 the Government enacted a law on IDD elimination, mandating universal salt iodization (USI) at 25-55 mg/kg. The present study aimed to evaluate the effectiveness of the USI strategy on the iodine consumption, iodine status and burden of IDD in the population of Kyrgyzstan.Design A national, population-representative survey during autumn 2007 collected household salt and urine samples of school-age children and pregnant women for quantitative iodine measurements. Thyroid volume was measured by ultrasound.Results The median iodine content in household salt was 11.2 mg/kg; 97.9 % of salt samples were iodized, but only 39.5 % had ≥15 mg iodine/kg. The median urinary iodine concentration (UIC) of 114 μg/l in children did not differ from the UIC of 111 μg/l in pregnant women. Thyroid volume in pregnant women increased with the duration of pregnancy. Strong relationships existed between salt iodine levels and the UIC values in children and women.Conclusions The iodine nutrition status of the Kyrgyz population is highly responsive to household salt iodization. Although the results in children suggest adequate iodine nutrition, the iodine consumption among pregnant women did not assure their dietary requirements. In-depth analysis of the survey data suggest that excess iodine intake is not likely to become a public health concern in Kyrgyzstan when the salt supply meets agreed standards. © 2009 The Authors.

Paployan V.A.,Slavonic University
Journal of Contemporary Physics | Year: 2015

The results of calculations of frequency of collective oscillations of electrons in metallic nanoshells are presented. The influence of interaction retardation is taken into account by the Rayleigh method. It is shown that the retardation results in a considerable decrease of the oscillation frequency, which, in its turn, reduces the radiation width of the spectrum. As a result, the spectral sensitivity of nanoshells is increasing. © 2015, Allerton Press, Inc.

Tevosyan H.K.,Slavonic University
Journal of Contemporary Physics | Year: 2012

Quantum states and energy levels of an electron in a spherical quantum dot with a modified Pöschel-Teller potential are studied. Analytical expressions for the wave function and energy of particle in the absence of impurity are obtained. Within the framework of variational method the impurity states are studied and by using numerical methods the dependences of the particle energy on the parameters of the spherical quantum dot are derived. Dependences of the electron binding energy on the half-width and depth of the potential well are revealed. © 2012 Allerton Press, Inc.

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