In the first, we found that the acoustic absorption coefficient was lower for random incidence than for normal incidence. Figure 3: Absoprtion coefficient for Si, Ge, GaAS, InP, CdTe. 3 Chemische Physik und Explosionsschutz, Abt. Als das nationale Metrologieinstitut Deutschlands ist die PTB oberste Instanz bei allen Fragen des richtigen und zuverlässigen Messens. All absorption grades (a ) and - if possible - scattering coefficients (s) known to us are listed and can be downloaded and used as you like. Values of the mass attenuation coefficient, μ/ρ, and the mass energy-absorption coefficient, … The most important requirement for a successful simulation of room acoustic parameters with computer simulation programs is the knowledge of the exact room geometry and above all of  the reflection properties of room limiting surfaces. You leave the selection by clicking on button "selection off" . Auf diesem Weg sorgt die PTB dafür, dass alle mit einheitlichen Maßen messen, nicht nur in Deutschland, sondern weltweit. fMax contains the octav centre frequency of the maximum value of absorption. PTB stopped its research activities in the field of room acoustics. After 400nm, the absorption coefficient depends on x, and significantly decrease just as the materials before. UK Installation Service . Die PTB gehört zu den ersten Adressen in der internationalen Welt der Metrologie. Click on an arrow and then on your chosen code-nr.. Click on button "selection". Der Anteil an Forschung und Entwicklung beträgt rund zwei Drittel aller PTB-Aktivitäten. Absorption Coefficient Chart Back to Home. fMax = 1000 Hz, or a max < 0.8. Button "entire data" is available again. Metrologie ist keine nationale Angelegenheit. Sound Absorption . This section in Wikipedia gives us a clue. Ein weltweit einheitliches Maßsystem − als Grundlage für Wirtschaft, Technik und Forschung − kann nur durch internationale Zusammenarbeit und Vertrauen entstehen. Further you can choose "user definable" and define one or more conditions that your problem requires: e.g. Here we can observe that from 250nm to 400nm the absorption coefficient is the same for all values of x. Die PTB trägt durch ihre Arbeit maßgeblich dazu bei. It says. More than 2000 data sets are … 9 Gesetzliche und internationale Metrologie, Institute for Exp. ənt] Also known as absorption factor; absorption ratio; coefficient of absorption. All absorption grades (a ) and - if possible - scattering coefficients (s) known to us are listed and can be downloaded and used as you like. 8 Medizinphysik und metrologische Informationstechnik, Abt. E.g. 7 Temperatur und Synchrotronstrahlung, Abt. It has been kept up to date until PTB stopped its activity in room acoustics research. (acoustics) The ratio of the sound energy absorbed by a surface of a medium or material to the sound energy incident on the surface. Absorption coefficients for 200 nm and 900 nm are almost equal at 6.9 m−1 (attenuation length of 14.5 cm).. Those numbers are reciprocal, and reading the links shows the terms refer to $1/e$ lengths, natural units.. Floor Soundproofing . Thus, the following information is provided without any further support. This value is displayed in the column a max. More than 2000 data sets are available. Quantum Metrology (QUEST), Metrologie für ultra-niedrige Magnetfelder, Vertrauenspersonen / Ombudspersonen für die gute wissenschaftliche Praxis. Sheet "graph" opens and you can take a look at the chosen data by clicking on button "selected data". The user can sort the data with Excel functions by selected criteria: some columns contain functions that deliver interesting criteria for sorting.