Effect of absorber geometry on apparent absorption coefficients as measured in a reverberation chamber

1981 ◽  
Vol 69 (4) ◽  
pp. 1065-1074 ◽  
Author(s):  
Thomas W. Bartel
Keyword(s):  
Absorption Coefficients ◽  
Reverberation Chamber ◽  
Apparent Absorption

scholarly journals Angle-Dependent Absorption of Sound on Porous Materials

Acoustics ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 753-765
Author(s):  
Jose Cucharero ◽  
Tuomas Hänninen ◽  
Tapio Lokki
Keyword(s):  
Sound Absorption ◽  
Glass Wool ◽  
Room Acoustics ◽  
Sound Waves ◽  
Absorption Coefficients ◽  
Reverberation Chamber ◽  
Impedance Tube ◽  
Material Development ◽  
Dependent Absorption ◽  
Good Agreement

Sound-absorbing materials are usually measured in a reverberation chamber (diffuse field condition) or in an impedance tube (normal sound incidence). In this paper, we show how angle-dependent absorption coefficients could be measured in a factory-type setting. The results confirm that the materials have different attenuation behavior to sound waves coming from different directions. Furthermore, the results are in good agreement with sound absorption coefficients measured for comparison in a reverberation room and in an impedance tube. In addition, we introduce a biofiber-based material that has similar sound absorption characteristics to glass-wool. The angle-dependent absorption coefficients are important information in material development and in room acoustics modeling.

Interfacial properties of GaSb/InAs superlattices

1993 ◽  
Vol 51 ◽  
pp. 826-827
Author(s):  
M. E. Twigg ◽  
B. R. Bennett ◽  
J. R. Waterman ◽  
J. L. Davis ◽  
B. V. Shanabrook ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Molecular Beam ◽  
Infrared Detector ◽  
Interfacial Properties ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Short Period ◽  
High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

Estimation of chlorophyll content by absorption spectra of native Spirulina platensis cells

2020 ◽  
pp. 25-33
Author(s):  
Leonid E. Paramonov
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Absorption Spectra ◽  
Spirulina Platensis ◽  
Intracellular Concentration ◽  
Absorption Coefficients

A method for retrieving the absorption coefficients of Spirulina platensis pigments using absorption spectra of native cells and excluding the use of extracts is considered. Estimates of the intracellular concentration of chlorophyll a, С-phycoerythrin, С- phycocyanin and allophycocyanin in native cells are discussed.

Research on Characteristics of Field Uniformity in Reverberation Chamber Using Two TX Antennas

2012 ◽  
Vol E95.B (7) ◽  
pp. 2386-2392
Author(s):  
Jung-Hoon KIM ◽  
Tae-Heon JANG ◽  
Sung-Kuk LIM ◽  
Songjun LEE ◽  
Sung-Il YANG
Keyword(s):  
Reverberation Chamber ◽  
Field Uniformity

The Field Uniformity Analysis in a Triangular Prism Reverberation Chamber with a QRD

2011 ◽  
Vol E94-B (1) ◽  
pp. 334-337 ◽  
Author(s):  
Jung-Hoon KIM ◽  
Hye-Kwang KIM ◽  
Eugene RHEE ◽  
Sung-Il YANG
Keyword(s):  
Triangular Prism ◽  
Reverberation Chamber ◽  
Field Uniformity
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