Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "excitation" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Energy Analysis of Cavitation Bubbles Under Dual-Frequency Acoustic Excitation
Autorzy:
Lv, Liang
Hu, Kai
Liu, Fei
Li, Yawei
Cui, Bing
Powiązania:
https://bibliotekanauki.pl/articles/31339947.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
dual-frequency acoustic excitation
power
sonoluminescence
sonochemistry
Opis:
Cavitation has been widely used in wastewater degradation, material synthesis and biomedical field under dual-frequency acoustic excitation. The applications of cavitation are closely related to the power (i.e. the rate of internal energy accumulation) during bubble collapse. The Keller–Miksis equation considering liquid viscosity, surface tension and liquid compressibility is used to describe the radial motion of the bubble. The model is built in predicting the power during bubble collapse under dual-frequency acoustic excitation. The influences of parameters (i.e. phase difference, frequency difference, and amplitude ratio) on the power are investigated numerically. With the increase of phase difference, the power can be fluctuated in a wide range at all conditions. Three typical characteristics of the power appear under the effects of frequency difference and amplitude ratio. With the increase of amplitude ratio, if the frequency difference is small, the power has two maximum values; and if the frequency difference is medium, there is a maximum value. Otherwise, the power monotonously decreases. The results can provide theoretical references for the selections of experimental parameters of sonoluminescence and sonochemistry in the dual-frequency acoustic field.
Źródło:
Archives of Acoustics; 2022, 47, 4; 513-518
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient Processes Associated with Turning an Antenna On and Off
Autorzy:
Witenberg, Anna
Powiązania:
https://bibliotekanauki.pl/articles/27311952.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
effective light meter
pulse excitation
transient processes in antenna
Opis:
The paper discusses the phenomena accompanying switching the sinusoidal excitation of an antenna on and off when the antenna is excited by a train of sinusoids containing several to several hundred periods. Transient phenomena are presented against the background of the resonant properties of the antenna. The processes of turning the antenna on and off take place under different conditions and therefore are different. When the antenna is switched on, the transient processes are determined by the antenna properties and the excitation properties. When the antenna is switched off, excitation is no longer present, and the properties of the antenna determine the transient process. We define a new measure of time: the effective light meter.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 4; 675--681
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutually Orthogonal Golay Complementary Sequences in Medical Ultrasound Diagnostics. Experimental Study
Autorzy:
Trots, Ihor
Żołek, Norbert
Tasinkevych, Yuriy
Wójcik, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/31340110.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
coded excitation
mutually orthogonal Golay codes
synthetic aperture
ultrasound imaging
Opis:
The objective of this paper is an experimental study of the most crucial parameters of the received acoustic signals (e.g. signal-to-noise ratio (SNR), side-lobes level (SLL), axial resolution) obtained as a result of simultaneous emission of mutually orthogonal Golay complementary sequences (MOGCS) to demonstrate their feasibility of being used in ultrasound diagnostics. Application of the MOGCS in ultrasound measurements allows the image reconstruction time to be shortened without decreasing the resulting quality of reconstructed images in comparison with regular complementary Golay coded sequences (CGCS). In this paper two sets of 16-bits long MOGCS were implemented in the Verasonics Vantage™ (Verasonics Inc., Kirkland, WA, USA) scanner. Ultrasound data were generated using a perfect reflector, a custom-made nylon wire phantom and tissue mimicking phantom. Parameters of the detected MOGCS echoes like SNR, SLL and axial resolution were determined and compared to that of the standard CGCS and the short two-sine cycles pulse. It was evidenced that applying MOGCS did not compromise the parameters of the separated and compressed echoes in comparison to the other types of transmitted signal – the CGCS and the short pulse. Concretely, both the MOGCS and CGCS yield similar SNR increase in comparison to the short pulse. Almost similar values of the axial resolution estimated at the full width at the half maximum level for all types of the transmitted signals were also obtained. At the same time, using the MOGCS the data acquisition speed can be increased twice in comparison with the CGCS signal.
Źródło:
Archives of Acoustics; 2022, 47, 3; 399-405
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulse Excitation in a Watertight Steel Circular Cylindrical Shell and Influence of Structural Configuration on Underwater Radiated Noise
Autorzy:
Wu, Chen-I
Too, Gee-Pinn
Wu, Bo-Hsien
Powiązania:
https://bibliotekanauki.pl/articles/31339791.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
impulse excitation
influence of structural configuration
FEM analysis
underwater noise radiation characteristics
Opis:
This study used experimental measurements and the finite-element method (FEM) simulations to investigate transient underwater radiated noise induced by the impulse excitation of water surrounding a watertight steel-structured circular cylindrical shell submerged in the 176 × 8 × 4 m towing tank. The excitation was caused by dropping an iron block onto a structural bracket in the shell to generate structural vibration. The experimental results were found to be consistent with the FEM results, with the difference between the experimental and simulated sound pressure levels being less than 3 dB. Moreover, it was determined that the structural vibration also generated airborne noise in the cylindrical shell, but this contributed much less than the impulse excitation to the induction of underwater radiated noise. Finally, analysis of the sound field of the underwater noise radiation showed that it was influenced by the wall thickness of the watertight steel cylindrical shell and that of the reinforced bracket seat structure. In particular, the structural reinforcement position proved to be the diffusion breakpoint of the underwater sound radiation. This demonstrates that compared with the studied structure, a thicker and more complex reinforced structure will transmit less or incomplete sound radiation into water.
Źródło:
Archives of Acoustics; 2023, 48, 4; 509-521
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies