Informacja

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

Wyszukujesz frazę "Kujawska, J." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Nonlinear and linear pressure determination in a two-layer structure: solid crystal - water at GHz frequencies
Autorzy:
Filipczyński, L.
Wójcik, J.
Kujawska, T.
Powiązania:
https://bibliotekanauki.pl/articles/332574.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
pressure determination
solid crystal
water
GHz frequencies
Opis:
Determination of acoustic pressures at the frequency of 1 GHz by means of PVDF hydrophones is not possible due to their limited frequency response. Moreover, the size of their active electrodes is by about 3 orders of magnitude greater than the resolution in the acoustic microscopes at such a high frequency. Therefore the authors solved this problem at first in a microscope with the working frequency of 34 MHz using both the numerical and experimental methods. A numerical procedure of nonlinear propagation and transducer power measurements were applied giving in effect the same quantitative results. Therefore the identical numerical procedure was used for the l GHz microscope working in the reflection mode. Many pressure field quantities of the microscope were shown, e.g. the pressure values, distributions of the first, second, third and fourth pressure harmonics in and outside of the focus, pulse distortions and their spectra, the resolutions achieved etc. The obtained information on nonlinear propagation effects in microscopy was previously lacking.
Źródło:
Hydroacoustics; 2003, 6; 143-150
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Foundation of the new method of numerical calculations of the nonlinear acoustics fields
Autorzy:
Wójcik, J.
Filipczyński, L.
Kujawska, T.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/332125.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
We explain, motivation behind this work and briefly describe foundation of new method which we have developed for efficient solution in PC environment of the nonlinear propagation equation with the boundary conditions applied for both circular and not circular transducers (like array). Comparison between new and old method will be presented for strongly nonlinear disturbance. At the end we will demonstrate the results of the numerical calculations of the nonlinear field propagating from the array.
Źródło:
Hydroacoustics; 2004, 7; 227-234
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possible temperature increases in soft tissues in the case of nonlinear and linear wave propagation
Autorzy:
Filipczyński, L.
Kujawska, T.
Tymkiewicz, R.
Wójcik, J.
Powiązania:
https://bibliotekanauki.pl/articles/332225.pdf
Data publikacji:
1997
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
It is well known that the nonlinear propagation increases the absorption of acoustic waves in the medium thus increasing the temperature effects. According to the recently developed new theoretical approach it is possible to determine in a simple way the effective absorption in the case of nonlinear propagation basing on the pulse spectrum analysis [Wójcik, 1996]. In this way it was possible to find the corresponding absorption values occuring in ultrasonography. In this case a classical PVDF membrane hydrophone was used to demonstrate and to measure nonlinear effects. Analysing the obtained wave spectra it was possible to determine the increase of the effective tissue absorption and hence to find the rate of heat generation per unit volume which is crucial for temperature elevations In this way possible temperature increases for the case of nonlinear and linear propagation can be determined.
Źródło:
Hydroacoustics; 1997, 1; 329-332
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ilościowa ocena nieliniowej propagacji w wodzie i w tkance
Autorzy:
Filipczyński, L.
Kujawska, T.
Tymkiewicz, R.
Wójcik, J.
Powiązania:
https://bibliotekanauki.pl/articles/331916.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
Nonlinear propagation effects were investigated numerically and experimentally u wate r and In blood from the point of view of ultrasonic diagnostic applications in cardlology. Pressure distributions of short and long pulses with the frequency of 3 and 3.5 MHz, radiated by a typical cardiological probe, were found along the ultrasonic beam axis. The numerial results were obtained by means of the numerical code Wf developed previously. The experimental pressure distributions were measured by memu of a membrane PYDF hydrophone. The obtained numerical and experimental results show ing the distributions of the 2-nd and I -st harmonics have shown good agreement allowing us to determine some diagnostic conclusions.
Źródło:
Hydroacoustics; 2000, 3; 53-56
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear equations of acoustics - numerical solutions and their visualization
Autorzy:
Wójcik, J.
Lewin, P. A.
Nowicki, A.
Filipczyński, L.
Kujawska, T.
Radulescu, E.
Powiązania:
https://bibliotekanauki.pl/articles/331971.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustics
nonlinear equations
wave equation
Opis:
The novel effective numeric solver of the nonlinear scalar wave equation describing the acoustic wave propagation in the attenuating media was derived. The solver was developed for the PC environment. The standard computation data include al! stationary and dynamic characteristics of the radiated ultrasonic pressure field, especially its 4D (space/time) visualization. The results obtained with the solver can be used as the supporting tools (tool) in designing and developments of the multielement linear and phase array transducers applied in ultrasonography.
Źródło:
Hydroacoustics; 2003, 6; 137-142
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

    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