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Wyszukujesz frazę "partial coherence" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Application for analysis of the multiple coherence function in diagnostic signal separation processes
Autorzy:
Wądołowski, Mariusz
Pankiewicz, Jarosław
Markuszewski, Damian
Powiązania:
https://bibliotekanauki.pl/articles/2146598.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
partial coherence
signal separation
machine diagnostics
koherencja częściowa
separacja sygnałów
diagnostyka maszyn
Opis:
Diagnosing the condition of the machine during its operation by non-invasive methods is most often reduced to measuring the acceleration of vibrations occurring on the housing, as close as possible to the observed element or changes in sound pressure in the immediate vicinity of the machine. For proper inference about the condition of a given machine element, the registered signals should be undisturbed by signals coming from other components and free from external interference. In the case of simple stationary machines, it is quite simple, but in the case of more complex systems, such as a car, which in addition is in motion, things get complicated In the available literature we find examples of the effectiveness of using ordinary coherence function to separate signals from two independent sources[1,2,3]. This work presents attempt to build an algorithm that uses signals from a multi-point measurement system to analyze multiple coherence functions, which allows to separate signals from various sources. It can then get diagnostic information from the signal thus separated. The effectiveness of the algorithm was tested on a model simulating signal mixing, and then using signal coherence function and knowledge of the transmittance function, the signals were separated.
Źródło:
Vibrations in Physical Systems; 2020, 31, 3; art. no. 2020324
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wigner transform approach to dynamic-variable partially coherent laser beam characterization
Autorzy:
Jabczyński, J.
Gontar, P.
Gorajek, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/202109.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
laser beams
partial coherence
high-power continuous-wave lasers
Wigner transform
aberrations
Opis:
1) Background: the modeling, characterization, transformation and propagation of high-power CW laser beams in optical (including fiberoptic) trains and in the atmosphere have become hot topics in laser science and engineering in the past few years. Single-mode output is mandatory for high-power CW laser applications in the military field. Moreover, an unstationary, dynamic operation regime is typical. Recognized devices and procedures for laser-beam diagnostics could not be directly applied because of dynamic behavior and untypical non-Gaussian profiles. 2) Methods: the Wigner transform approach was proposed to characterize dynamically variable high-power CW laser beams with significant deterministic aberrations. Wavefront-sensing measurements by means of the Shack-Hartmann method and decomposition into an orthogonal Zernike basis were applied. 3) Results: deterministic aberration as a result of unstationary thermal-optic effects depending on the averaged power of the laser output was found. Beam quality determined via the Wigner approach was changed in the same way as the measurements of the beam diameter in the far field. 4) Conclusions: such an aberration component seems to be the main factor causing degradation in beam quality and in brightness of high-power CW laser beams.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 141-146
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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