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31.
A. O. Vardanyan E. M. Laziev A. O. Melikyan D. L. Hovhannisyan V. O. Chaltykyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2009,44(5):245-249
We present a scheme of multibeam cross-correlator which allows high-temporal resolution measuring of durations of picosecond
and subpicosecond pulses of terahertz range. 相似文献
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33.
A. A. Hakhoumian G. D. Hovhannisyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2014,49(2):60-68
We consider the process of generation of difference frequency in a GaAs crystal with periodic domain structure during propagation of a few-cycle laser pulse in the crystal in the regime of weakly expressed chromatic dispersion. Method of lines is used to obtain numerical solution to the system of coupled nonlinear differential equations in partial derivatives describing the evolution of the electric field of a few-cycle laser pulse in GaAs crystal both with periodic and aperiodic domain structure. It is shown that employing GaAs crystal with domain structure allows controlling the instantaneous frequency of broadband pulse radiation at difference frequency. 相似文献
34.
R. V. Hovhannisyan H. D. Khondkaryan M. S. Aleksanyan V. M. Arakelyan B. O. Semerjyan F. V. Gasparyan V. M. Aroutiounian 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2014,49(4):151-157
Thin film gas sensors based on nanocomposite In2O3·Ga2O3·SnO2 (70:20:10) have been manufactured by the high-frequency magnetron sputtering method. The technological cycle of sensor fabrication processes is described. Sensitivity of the prepared sensors at the temperature of working body 250°C and low-frequency noises within the 1–300 Hz range were investigated. The response of sensors to vapors of ethanol and acetone was investigated using resistive and noise methods. It is shown that the value of the sensitivity measured by the noise method exceeds the value of sensitivity measured by the resistive method. Sensors show appreciable sensitivity to the ethanol vapors already at working body temperature 150°C. Sensors can be used for the detection of low concentrations of ethanol vapors. The monotonous increase in the sensitivity of these sensors with increase in the ethanol and acetone vapors content allows applying nanosensors also for fast determination of gases concentration in air. 相似文献
35.
L. A. Hovhannisyan A. Zh. Muradyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2010,45(1):12-16
On the basis of the well-known Raman-Nath approximation, we have obtained a new analytical form for the amplitude of the resonant
Kapitza-Dirac scattering of an atom in the field of counter-propagating laser pulses. Comparison of the obtained formula with
that in the Raman-Nath approximation shows that the former describes, in addition to coherent diffraction, also channeling
of atoms in a periodic field of counter-propagating laser pulses. 相似文献
36.
A. H. Hovhannisyan S. G. Rafayelyan 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2007,42(5):292-295
The paper studies the initial value problem for a class of equations satisfying Huygens’ principle. Since this equations have singularities at t = 0, it is necessary first to determine the form of the initial conditions and then the solution of the corresponding problem is constructed in a finite number of steps. Examples of natural initial data are presented. 相似文献
37.
Topuzyan V. O. Hovhannisyan A. A. Makichyan A. T. Hunanyan L. S. Galstyan L. Kh. 《Russian Journal of Organic Chemistry》2022,58(2):236-243
Russian Journal of Organic Chemistry - The use of O-benzoyl protection in the synthesis of N-benzoyl-α,β-dehydrotyrosine benzylamide, and the corresponding 4-imidazolone was studied. The... 相似文献
38.
The interaction of different 3-acetylfuran-2(5H)-ones (1, 4) with dimethylformamide dimethyl acetal (DMF/DMA) has been investigated, and the condensed furopyridine system 3 was obtained. By means of interaction of compounds 4 and DMF/DMA via the 3-acetylfuran-2(5H)-one enamines, the heterocyclic substituted furanones are obtained. The condensation of 3-acetyl-4,5,5-trimethylfuran-2(5H)-one (1a) with veratraldehyde was realized. Through the interaction of 1a with malononitrile and further intramolecular condensation of the product, 6-amino-dihydroisobenzofuran-5-carbonitrile was also synthesized. 相似文献
39.
A. R. Balabekyan A. S. Danagulyan J. R. Drnoyan N. A. Demekhina G. H. Hovhannisyan A. E. Simonyan J. Adam A. A. Solnishkin V. M. Tsoupko-Sytnikov 《Physics of Atomic Nuclei》2011,74(5):665-670
Cross sections for the production of residual nuclei on the isotopes 112,118,120,124Sn irradiated with 0.66-, 1.0-, 3.65-, and 8.1-GeV proton beams were investigated. A ten-parameter semiempirical formula was
used to systematize the cross sections in question. A comparative analysis of parameter values obtained at different proton
energies was performed. 相似文献
40.
A.?G.?KamalyanEmail author M.?I.?Karakhanyan A.?H.?Hovhannisyan 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2018,53(3):134-138
By replacement in the definition of the convolution operator of Fourier transform by a spectral transform of a selfadjoint Sturm-Liouville operator on the axis L, the concepts of Lconvolution and L-Wiener-Hopf operators are introduced. The case of the reflectorless potentials with a single eigenvalue is considered. A relationship between the Wiener-Hopf and L-Wiener- Hopf operators is established. In the case of piecewise continuous symbol the Fredholm property and invertibility of the L-Wiener-Hopf operator are investigated. 相似文献