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Wyszukujesz frazę "acoustic analyses" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Exploring L1 Transfer in German Learners of English: High Front Vowels, High Back Vowels and the BED/BAD Distinction
Autorzy:
Kautzsch, Alexander
Powiązania:
https://bibliotekanauki.pl/articles/620568.pdf
Data publikacji:
2010-09-30
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
L1 transfer English/German
vowels
acoustic analyses
L2 acquisition
phonology
Opis:
Since the vowel systems of German and English are similar to some extent, German learners of English can be expected to transfer a considerable part of their German vowels to their L2 English. This paper traces the extent and source of positive and negative L1 transfer in two groups of university students from different German L1 backgrounds. To this end, acoustical analyses of three areas of vowel space are provided: high front vowels, high back vowels and mid/low front vowels. While positive transfer widely persists with high front vowels, learners refrain from consistently transferring high back vowels, probably owing to variability both in L1 German and in L2 English. In the case of mid/low front vowels negative transfer is reduced due to exposure to native English, and even more so due to formal instruction, which appears to accelerate the acquisition process
Źródło:
Research in Language; 2010, 8; 1-22
1731-7533
Pojawia się w:
Research in Language
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of wavy sea surface oil-derivative contamination with forward specular high-frequency scattering
Autorzy:
Pogorzelski, Stanisław
Rochowski, Paweł
Grzegorczyk, Maciej
Linde, Bogumił B. J.
Skrodzka, Ewa
Bielasiewicz, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/260616.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
crude oil contamination
capillary wave damping
acoustic surface scattering
statistical-frequency analyses
at-sea pollution detection
Opis:
A spectrum of low-frequency (20‒30 Hz) amplitude fluctuations of the ultrasonic (10 MHz) signal specularly scattered from water surfaces covered with monomolecular and thicker crude oil origin films of well-defined, oceanographically relevant viscoelastic properties was examined in laboratory and at-sea conditions. The relationship between the Surface water wave (30 Hz) damping coefficient and the oil layer thickness was established, and compared to the one predicted by the classical Stokes theory. The depression of the spectral energy density of wind-driven waves by surface films was inferred from the ratio of acoustic signal fluctuations spectra with/without films, and compared to that resulting from the Marangoni damping theory applicable to monolayers of particular surface viscoelasticity. The agreement between the theory and experimental data was satisfactory. As shown in at-sea experiments performed with a free-floating, buoy-like acoustic system, and an artificial oil slick spread over the Baltic Sea surface, the film’s rheological Surface properties can be recovered from acoustic surface probing, as well as oil spill edge detection. Simultaneous statistical analyses of the scattered signal amplitude distribution parameters turned out to be unequivocally related to the oil substance fraction weight, oil layer thickness, and the form of oil contamination.
Źródło:
Polish Maritime Research; 2020, 1; 173-179
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Analysis of Sensitivity of SAW Structure to the Effect of Toxic Gases
Autorzy:
Hejczyk, T.
Pustelny, T.
Wszołek, B.
Jakubik, W.
Maciak, E.
Powiązania:
https://bibliotekanauki.pl/articles/177695.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface acoustics wave SAW
SAW
Ingebrigtsen’s formula
gas diffusion equations
gaseous acoustic sensors
numerical analyses of SAW structures
Opis:
The paper presents the results of numerical analysis of the SAW gas sensor in the steady and non-steady states. The effect of SAW velocity changes vs surface electrical conductivity of the sensing layer is predicted. The conductivity of the porous sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. The Knudsen’s model of gas diffusion was used. Numerical results for the effect of gas CH4 on layers: WO3, TiO2, NiO, SnO2 in the steady state and CH4 in the non-steady state in recovery step in the WO3 sensing layer have been shown. The main aim of the investigation was to study thin film interaction with target gases in the SAW sensor configuration based on simple reaction-diffusion equation. The results of the numerical analysis allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness, operating temperature, and layer type. The numerical results basing on the code elaborated numerical system (written in Python language), were analysed. The theoretical results were verified and confirmed experimentally.
Źródło:
Archives of Acoustics; 2016, 41, 4; 747-755
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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