IRTUM – Institutional Repository of the Technical University of Moldova

Browsing Colecția instituțională by Subject "waves"

Browsing Colecția instituțională by Subject "waves"

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  • Application of acoustic emission technique for the evaluation of micromechanical properties of steel 
    GRABCO, D. Z.; SHIKIMAKA, O. A.; PYRTSAC, C. M.; PRISACARU, A. A.; ALEXANDROV, S. E. (Institutul de Fizică Aplicată al AŞM, 2018)
    Acoustic emission (AE) is the propagation of elastic waves by a material, caused by a dynamic local restructuring of its structure. According to modern physical concepts, AE, which occurs when indenting solids, is associated ...
  • Body zero frequency modes in photonic crystals of nanopores and nanocylinders 
    SERGENTU, Vladimir; URSAKI, Veaceslav; SIRBU, Lilian (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2013)
    In this paper, we demonstrate that body zero frequency modes can exist at extremely low frequencies in a system of nanocylinders made of non-dissipative material. Such kind of modes is not specific to single nanocylinders, ...
  • Compact Modules for Wireless Communication Systems in the E-Band (71–76 GHz) 
    MONTERO-DE-PAZ, Javier; OPREA, Ion; RYMANOV, Vitaly; BABIEL, Sebastian; GARCÍA-MUÑOZ LUIS, Enrique; LISAUSKAS, Alvydas; HOEFLE, Matthias; JIMENEZ, Álvaro; COJOCARI, Oleg; SEGOVIA-VARGAS, Daniel; PALANDÖKEN, Merih; TEKIN, Tolga; STÖHR, Andreas; CARPINTERO, Guillermo (Springer Nature Switzerland, 2013)
    The millimeter-wave spectrum above 70 GHz provides a cost-effective solution to increase the wireless communications data rates by increasing the carrier wave frequencies. We report on the development of two key components ...
  • Competing spin waves and superconducting fluctuations in strongly correlated electron systems 
    MOSKALENKO, V. A.; ENTEL, P.; DIGOR, D. F.; DOHOTARU, L. A. (Taylor & Francis, 2005)
    A special diagram technique recently proposed for strongly correlated electron systems is used to study the pecularities of a spindensity-wave (SDW) in competition with superconductivity. This method allows to formulate ...
  • Convolver on multileading-out acoustic-electronic cryotron 
    NISTIIUK, Pv.; TSURKAN, D. N.; ALEXEI, A. S.; BEREGOI, E. A.; BIRZOI, O. (IEEE, 2001)
    The results of a convolver on tunable acoustic-electronic cryotron elaboration are presented. The performances and parameters of a convolver depend on the frequency surface acoustic waves (SAW), amount and configurations ...
  • Effective light absorption spectra of endogenic porphyrins in soft biotissue 
    SONTEA, V. P.; ABRAMOVICH, N. D.; BARUN, V. V.; DICK, S. K.; SERYAKOV, A. (IEEE, 2015)
    Light action spectra for main skin chromophores are simulated. Endogenic porphyrins (Pp IX, Cp III, and Up III) are selected as target chromophores. They can produce singlet oxygen (SO) under tissue irradiation, which acts ...
  • Infrared lattice vibration study of CuIn5S8 
    NEUMANN, H.; SOBOTTA, H.; RIEDE, V.; TEZLEVAN, V. E.; SYRBU, N. N. (WILEY‐VCH Verlag GmbH & Co. KGaA, 1990)
    Infrared reflectivity spectra of the spinel compound CuIn5S8 are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. It is found that the spectra are dominated by two strong modes with frequencies ...
  • Infrared lattice vibrations of PbGa2S4 
    NEUMANN, H.; SOBOTTA, H.; SYRBU, N. N.; GOLOVEI, V. M. (WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim, 1994)
    Infrared reflectivity spectra of PbGa2S4 single crystals are measured at room temperature in the wavenumber range from 30 to 4000 cm−1 for the polarization directions E ∥ c and E ∥ b. The frequencies of 13 B1u modes and ...
  • Infrared Lattice Vibrations of TI3AsS4 
    NEUMANN, H.; SOBOTTA, H.; RIEDE, V.; KAMBA, S.; SYRBU, N. N.; GOLOVEI, M. I. (WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim, 1992)
    Infrared reflectivity spectra of TI3AsS4 single crystals are measured at room temperature in the wavenumber range from 30 to 4000 cm−1 for the polarization directions E‖ c and E ‖ a. An analysis of the spectra with the ...
  • Interference of birefractive waves in CdGa2S4 crystals 
    SYRBU, N. N.; TIRON, A. V.; PARVAN, V. I.; ZALAMAI, V. V.; TIGINYANU, I. M. (Elservier, 2015)
    In СdGа2S4 crystals the Fabry–Perot and birefringence interference spectra were investigated. Spectral dependences of refraction indexes for ordinary (no) and extraordinary (ne) light waves are defined. The spectral ...
  • Interference of exciton-polariton waves in GaSe nanocrystals 
    ZALAMAI, V. V.; STAMOV, I. G.; SYRBU, N. N. (Elsevier, 2021)
    Absorption, reflection, photoluminescence and wavelength modulation transmission spectra of GaSe single crystals were investigated in temperature rage 300 – 10 K. From fitting of contours of excitonic reflection spectra ...
  • Interference of ordinary and extraordinary waves in AgAsS2 crystals 
    SYRBU, N. N.; STAMOV, I. G.; URSAKI, V. V.; PARVAN, V.; IVANENCO, Yu. (ELSEVIER, 2012)
    The anisotropy of the near-bandgap absorption is investigated in AgAsS2 crystals. The refraction indices, n and n respectively for the Ec and Ec polarizations as well as the spectral dependence of the refraction ...
  • Investigation of red-emitting distributed Bragg reflector lasers by means of numerical simulations 
    TRONCIU, Vasile Z.; WENZEL, Hans; RADZIUNAS, Mindaugas; REGGENTIN, Matthias; WIEDMANN, Jörg; KNIGGE, Andrea (The Institution of Engineering and Technology, 2018)
    The authors report theoretical and experimental results on the properties of distributed Bragg reflector semiconductor lasers. Using the traveling wave equation model, they show that a proper choice of coupling coefficient ...
  • A method of virtual image for determination of negative refraction index of a nanomedium 
    SERGENTU, V.; URSAKI, V. (Romanian Academy Publishing House, 2017)
    In this paper we propose a method for measuring the negative refraction index of films of optically transparent materials. The method is based on recording the direction of propagation and the shifting of the ray reflected ...
  • Numerical and experimental investigations of micro-integrated external cavity diode lasers 
    TRONCIU, V. Z.; RADZIUNAS, M.; KÜRBIS, Ch.; WENZEL, H.; WICHT, A. (Springer Nature Switzerland, 2015)
    We report the results of numerical and experimental investigations of the electro-optical behaviour of an external cavity diode laser device composed of a semiconductor laser and a distant Bragg grating, which provides an ...
  • Numerical simulation of the amplification of picosecond laser pulses in tapered semiconductor amplifiers and comparison with experimental results 
    TRONCIU, V. Z.; SCHWERTFEGER, S.; RADZIUNAS, M.; KLEHR, A.; BANDELOW, U.; WENZEL, H. (Elsevier, 2012)
    We apply a traveling wave model to the simulation of the amplification of laser pulses generated by Q-switched or mode-locked distributed-Bragg reflector lasers. The power amplifier monolithically integrates a ridge-waveguide ...
  • Resonant-tunnelling diodes for THz applications 
    FEIGINOV, Michael; SYDLO, Cezary; COJOCARI, Oleg; MEISSNER, Peter (Society of Photo-Optical Instrumentation Engineers, SPIE, 2012)
    We investigate experimentally resonant-tunnelling-diode (RTD) oscillators, which are based on RTDs with heavily doped collector. We demonstrate that such RTD oscillators can work at frequencies, which are far beyond the ...
  • Spatial dispersion in polariton spectra of CuGaS2 crystals 
    SYRBU, N. N.; BLAJE, M.; TEZLEVAN, V. E.; URSAKI, V. V. (Springer Nature Switzerland, 2002)
    TIn this study, we obtained new data on the parameters of the long-wavelength exciton polaritons of the A series and studied the wavelength-modulated reflectivity spectra of the A, B, and C excitons, the luminescence ...
  • Spin density waves and superconductivity in strongly correlated electron systems 
    DIGOR, D. F.; DOHOTARU, L. A.; ENTEL, P.; MOSKALENKO, V. A.; VLADIMIR, M. I. (Academy of Sciences of Moldova, 2005)
    A special diagram technique recently proposed for strongly correlated electron systems is used to study the peculiarities of a spin-density-wave (SDW) in competition with superconductivity. This method allows to formulate ...
  • Theoretical Investigation of Striped and Non-Striped Broad Area Lasers With Off-Axis Feedback 
    LICHTNER, Mark; TRONCIU, Vasile Z.; VLADIMIROV, Andrei G. (IEEE, 2012)
    We report a method to improve the beam quality of broad area lasers by using a V-shaped external cavity formed by two off-axis feedback mirrors that allow to select a single transverse mode with transversally modulated ...

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