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Your search keyword '"Yurchenko, Stanislav O."' showing total 290 results
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290 results on '"Yurchenko, Stanislav O."'

51. Spectroscopy of Nafion in terahertz frequency range.

Author

Yurchenko, Stanislav O. and Zaytsev, Kirill I.

Subjects
*NAFION, *TERAHERTZ spectroscopy, *POLYMERS, *PERMITTIVITY, *DEBYE'S theory
Abstract

We report results on the terahertz (THz) spectroscopy of polymer Nafion. Using THz pulse spectroscopy and refined post-processing algorithms based on the ill-posed spectroscopic inverse problem analysis, we find the complex dielectric permittivity of Nafion to be in the range 0.15-1.5 THz. The results in the low-frequency (gigahertz) range agree well with known measurements. We find that the complex dielectric permittivity can be described well using the double-Debye model with relaxation times of 7.20×0.05 ps and 0.12×0.05 ps. This result is discussed briefly from the viewpoint of the appearance of a segregated structure in the "Nafion-water" system. [ABSTRACT FROM AUTHOR]

Published
2014
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52. Band-gap nonlinear optical generation: The structure of internal optical field and the structural light focusing.

Author

Zaytsev, Kirill I., Katyba, Gleb M., Yakovlev, Egor V., Gorelik, Vladimir S., and Yurchenko, Stanislav O.

Subjects
NONLINEAR optics, PHOTONIC crystals, PHOTONIC band gap structures, COMPUTER simulation, WAVELENGTHS, FINITE difference time domain method
Abstract

A novel approach for the enhancement of nonlinear optical effects inside globular photonic crystals (PCs) is proposed and systematically studied via numerical simulations. The enhanced optical harmonic generation is associated with two- and three-dimensional PC pumping with the wavelength corresponding to different PC band-gaps. The interactions between light and the PC are numerically simulated using the finite-difference time-domain technique for solving the Maxwell's equations. Both empty and infiltrated two-dimensional PC structures are considered. A significant enhancement of harmonic generation is predicted owing to the highly efficient PC pumping based on the structural light focusing effect inside the PC structure. It is shown that a highly efficient harmonic generation could be attained for both the empty and infiltrated two- and three-dimensional PCs. We are demonstrating the ability for two times enhancement of the parametric decay efficiency, one order enhancement of the second harmonic generation, and two order enhancement of the third harmonic generation in PC structures in comparison to the nonlinear generations in appropriate homogenous media. Obviously, the nonlinear processes should be allowed by the molecular symmetry. The criteria of the nonlinear process efficiency are specified and calculated as a function of pumping wavelength position towards the PC globule diameter. Obtained criterion curves exhibit oscillating characteristics, which indicates that the highly efficient generation corresponds to the various PC band-gap pumping. The highest efficiency of nonlinear conversions could be reached for PC pumping with femtosecond optical pulses; thus, the local peak intensity would be maximized. Possible applications of the observed phenomenon are also discussed. [ABSTRACT FROM AUTHOR]

Published
2014
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53. Accuracy of sample material parameters reconstruction using terahertz pulsed spectroscopy.

Author

Zaytsev, Kirill I., Gavdush, Arseniy A., Karasik, Valeriy E., Alekhnovich, Valentin I., Nosov, Pavel A., Lazarev, Vladimir A., Reshetov, Igor V., and Yurchenko, Stanislav O.

Subjects
BACKWARD wave oscillators, SPECTRUM analysis, MICROWAVE oscillators, RANDOM noise theory, STOCHASTIC processes
Abstract

New experimental and theoretical results for the material parameter reconstruction using terahertz (THz) pulsed spectroscopy (TPS) are presented. The material parameter reconstruction algorithm was realized and experimentally implemented to study the test sample. In order to both verify the algorithm and to estimate the reconstruction accuracy, test sample material parameters obtained with the TPS were compared with the results of the same sample studying by the use of the backward-wave oscillator (BWO) spectroscopy. Thus, high reconstruction accuracy was demonstrated for the spectral range, corresponding to the BWO sensitivity and located between 0.2 and 1.2 THz. The numerical simulations were applied for determining the material parameter reconstruction stability in the presence of white Gaussian noise in TPS waveforms as well as fluctuations in the femtosecond (FS) optical pulse duration. We report a strong dependence of the inverse problem solution stability on these factors. We found that the instability of the FS optical pulse duration used for THz pulses generation and detection limits the material parameter reconstruction with TPS. [ABSTRACT FROM AUTHOR]

Published
2014
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54. The shortest-graph method for calculation of the pair-correlation function in crystalline systems.

Author

Yurchenko, Stanislav O.

Subjects
*ANISOTROPIC crystals, *INTEGRAL equations, *COLLOIDS, *MOLECULAR dynamics, *DIRAC equation
Abstract

A new method for approximate calculation of the pair correlation function g(r) is proposed for crystalline systems of identical particles with isotropic interactions. The main idea of the method is to account for the relative delocalization of each node in g(r) by using only the shortest lattice graph between the given points, thus neglecting smaller contributions from other (non-shortest) graphs. By employing the Lennard-Jones and Yukawa crystalline systems as representative examples, it is shown that the proposed approach yields very good agreement with the results of molecular dynamics simulations up to the melting line. The approach can be useful in approximating the structure of simple crystals (in particular, of crystalline colloids and plasma crystals), and can also be generalized for systems with anisotropic interactions. [ABSTRACT FROM AUTHOR]

Published
2014
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55. Sapphire Photonic Crystal Waveguides for Terahertz Sensing in Aggressive Environments

Author

Katyba, Gleb M., primary, Zaytsev, Kirill I., additional, Chernomyrdin, Nikita V., additional, Shikunova, Irina A., additional, Komandin, Gennady A., additional, Anzin, Vladimir B., additional, Lebedev, Sergey P., additional, Spektor, Igor E., additional, Karasik, Valeriy E., additional, Yurchenko, Stanislav O., additional, Reshetov, Igor V., additional, Kurlov, Vladimir N., additional, and Skorobogatiy, Maksim, additional

Published
2018
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58. Terahertz dielectric spectroscopy of malignancies (Conference Presentation)

Author

Gavdush, Arseniy A., primary, Chernomyrdin, Nikita V., additional, Beshplav, Sheyh–Islyam, additional, Malakhov, Kirill M., additional, Kucheryavenko, Anna S., additional, Dolganova, Irina N., additional, Yurchenko, Stanislav O., additional, Goryainov, Sergey A., additional, Kurlov, Vladimir N., additional, Reshetov, Igor V., additional, and Zaytsev, Kirill I., additional

Published
2018
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59. In vitro terahertz spectroscopy of gelatin-embedded human brain tumors: a pilot study

Author

Zaytsev, Kirill I., primary, Chernomyrdin, Nikita V., primary, Gavdush, Arseniy A., primary, Beshplav, Sheyh-Islyam T., primary, Malakhov, Kirill M., primary, Kucheryavenko, Anna S., primary, Katyba, Gleb M., primary, Dolganova, Irina N., primary, Goryaynov, Sergey A., primary, Karassik, Valeriy E., primary, Spector, Igor E., primary, Kurlov, Vladimir N., primary, Yurchenko, Stanislav O., primary, Komandin, Gennadiy A., primary, Potapov, Alexander A., primary, and Tuchin, Valery V., primary

Published
2018
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60. Colloidal suspensions in external rotating electric field: experimental studies and prospective applications in physics, material science, and biomedicine

Author

Rodionov, Ilya A., primary, Zaytsev, Kirill I., primary, Cherkasova, Olga P., primary, Tuchind, Valery V., primary, Yurchenko, Stanislav O., primary, Yakovlev, Egor V., primary, Troshina, Anna V., primary, Korsakova, Sofia A., primary, Aliev, Ismail N., primary, and Andronik, Mikhail, primary

Published
2018
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67. Tunable two-dimensional assembly of colloidal particles in rotating electric fields

Author

Yakovlev, Egor V., primary, Komarov, Kirill A., additional, Zaytsev, Kirill I., additional, Kryuchkov, Nikita P., additional, Koshelev, Kirill I., additional, Zotov, Arsen K., additional, Shelestov, Dmitry A., additional, Tolstoguzov, Victor L., additional, Kurlov, Vladimir N., additional, Ivlev, Alexei V., additional, and Yurchenko, Stanislav O., additional

Published
2017
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70. Solid immersion terahertz imaging with sub-wavelength resolution

Author

Chernomyrdin, Nikita V., primary, Schadko, Aleksander O., additional, Lebedev, Sergey P., additional, Tolstoguzov, Viktor L., additional, Kurlov, Vladimir N., additional, Reshetov, Igor V., additional, Spektor, Igor E., additional, Skorobogatiy, Maksim, additional, Yurchenko, Stanislav O., additional, and Zaytsev, Kirill I., additional

Published
2017
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72. Wide-aperture aspherical lens for high-resolution terahertz imaging

Author

Chernomyrdin, Nikita V., primary, Frolov, Maxim E., additional, Lebedev, Sergey P., additional, Reshetov, Igor V., additional, Spektor, Igor E., additional, Tolstoguzov, Viktor L., additional, Karasik, Valeriy E., additional, Khorokhorov, Alexei M., additional, Koshelev, Kirill I., additional, Schadko, Aleksander O., additional, Yurchenko, Stanislav O., additional, and Zaytsev, Kirill I., additional

Published
2017
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75. Terahertz waveguides based on multichannel sapphire shaped crystals

Author

Katyba, Gleb M., additional, Zaytsev, Kirill I., additional, Shikunova, Irina A., additional, Rossolenko, Sergei N., additional, Chernomyrdin, Nikita V., additional, Karasik, Valeriy E., additional, Mukhina, Elena E., additional, Reshetov, Igor V., additional, Yurchenko, Stanislav O., additional, and Kurlov, Vladimir N., additional

Published
2016
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76. Principle component analysis and linear discriminant analysis of multi-spectral autofluorescence imaging data for differentiating basal cell carcinoma and healthy skin

Author

Chernomyrdin, Nikita V., additional, Zaytsev, Kirill I., additional, Lesnichaya, Anastasiya D., additional, Kudrin, Konstantin G., additional, Cherkasova, Olga P., additional, Kurlov, Vladimir N., additional, Shikunova, Irina A., additional, Perchik, Alexei V., additional, Yurchenko, Stanislav O., additional, and Reshetov, Igor V., additional

Published
2016
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