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Wyszukujesz frazę "Schäfer, H." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
A Study on the Correlation between Wood Moisture and the Damping Behaviour of the Tonewood Spruce
Autorzy:
Göken, J.
Fayed, S.
Schäfer, H.
Enzenauer, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030781.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
spruce wood
musical instruments
wood moisture
damping measurement
Opis:
In acoustic musical instruments special attention needs to be paid to those particularly sensitive parts made of tonewood whose function is to respond to vibrations. One of the most important tonewoods is spruce because of its good resonance properties. Spruce is especially used for soundboards, these being the primary source of sound. Piano manufacturers dry their soundboards to approximately 6% wood moisture, at which drying stage they are glued into the instrument. Fluctuations of the moisture content in the wood affect the tone. With changing moisture content, the instrument can go out of tune, even cracks can appear at very low moisture content in the wood. In addition, the tone colour will change. This may result from changes in the hammer felt or from changes in the vibration properties of the soundboard. Strain- and frequency-dependent damping measurements were carried out on spruce wood at different wood moisture contents in order to investigate the effect of the moisture content on the vibration behaviour. Wood which is slowly dried in air for several years is preferably used for high-class pianos. Therefore, damping measurements on new and on more than 130-year old spruce wood samples were performed.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1241-1260
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations on ZnSe/GaAs Interface by Treatment of GaAs (2×4) Surface with Te and Mg
Autorzy:
Ebel, R.
Spahn, W.
Ress, H. R.
Albert, D.
Schäfer, H.
Ehinger, M.
Faschinger, W.
Landwehr, G.
Powiązania:
https://bibliotekanauki.pl/articles/1950745.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Bd
68.65.+g
Opis:
The heterovalent interface ZnSe/GaAs, despite the small lattice misfit, still poses certain problems. The condition of the substrate surface prior to growth start determines the initial growth conditions, which on the other hand are assumed to be responsible for defect densities. Since Zn, in contrast to Se, hardly binds to GaAs the initial surface during growth start is essentially Se terminated. Therefore the binding of Mg to Se terminated GaAs was investigated. The structural quality of 140 nm thick ZnSe layers on different MgSe coverages were compared to conventionally grown and Te initiated ZnSe epilayers of the same thickness.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 767-772
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical methods in underwater acoustics - sound propagation and backscattering
Autorzy:
Nolte, B.
Ehrlich, J.
Hofmann, H.-G.
Schäfer, I.
Schäfke, A.
Stoltenberg, A.
Burgschweiger, R.
Powiązania:
https://bibliotekanauki.pl/articles/331712.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
stochastic ray tracing
German Navy
Opis:
This report summarizes an overview given at the XXXII Symposium on Hydroacoustics (SHA 2015) over several modelling techniques that are used in the context of military applications at the Research Department FWG of the German Bundeswehr Technical Centre for Ships and Naval Weapons, Maritime Technology and Research (WTD 71). For the modelling and understanding of sound propagation a physical model consisting of a tank for scaled measurements and the corresponding numerical simulation is presented. The basic formalism of stochastic ray tracing of the German Navy sonar simulation MOCASSIN is explained and compared to traditional deterministic ray tracing including the comparison with measurements. Strategies for the approximate calculation of the sonar target strength of large underwater objects with the use of boundary element methods, fast multipole methods and a ray-based algorithm are presented and the results of the calculations of several test objects are shown.
Źródło:
Hydroacoustics; 2015, 18; 127-140
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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