A relativistically corrected total absorption coefficient and a corrected upper bound for Rosseland opacities

1970 ◽  
Vol 10 (5) ◽  
pp. 511-513
Author(s):  
H.O. Dogliani
Keyword(s):  
Absorption Coefficient ◽  
Upper Bound ◽  
Total Absorption ◽  
Total Absorption Coefficient

Optimization of space-constrained micro-perforated absorbers by causality criteria

2021 ◽  
Vol 263 (6) ◽  
pp. 275-286
Author(s):  
Teresa Bravo ◽  
Cedric Maury
Keyword(s):  
Absorption Coefficient ◽  
Low Frequency ◽  
Single Layer ◽  
Optimization Procedure ◽  
Separation Distance ◽  
Physical Parameters ◽  
Total Absorption ◽  
Causality Criterion ◽  
Selection Of ◽  
Total Absorption Coefficient

The problem of space-constrained absorbers in the low frequency range constitutes an area of continuous research. Micro-perforated panels are advantageous because they can be tuned by a proper selection of their constitutive physical parameters including the diameter of the perforations and their separation distance, their thickness and the length of the backing cavity. However, such optimal selection is not straightforward, especially when considering multi-layer partitions. Current optimization algorithms are based on the maximization of the total absorption coefficient averaged over a frequency band, that requires a compromise between the bandwidth and the thickness of the control device. In this work, the problem is analysed on the basis of a causality criterion. This principle is generalized from its formulation in the field of electromagnetism to obtain a relation that correlates the thickness-to-bandwidth performance of a micro-perforated absorber to its total absorption coefficient. Using this relation, an optimization procedure is presented for the sequential selection of the optimal physical parameters for single-layer partitions. An excellent agreement has been found between the optimal values obtained by the causality criterion and those achieved by critical coupling conditions.

Preliminary results of an algorithm to determine the total absorption coefficient of water

2016 ◽  
Author(s):  
Suresh Thayapurath ◽  
Madhubala Talaulikar ◽  
Erwin J. A. Desa ◽  
Aneesh Lotliker
Keyword(s):  
Absorption Coefficient ◽  
Total Absorption ◽  
Preliminary Results ◽  
Total Absorption Coefficient

scholarly journals Linear and Nonlinear Intersubband Optical Properties of Direct Band Gap GeSn Quantum Dots

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 124 ◽  
Author(s):  
Mourad Baira ◽  
Bassem Salem ◽  
Niyaz Madhar ◽  
Bouraoui Ilahi
Keyword(s):  
Quantum Dots ◽  
Refractive Index ◽  
Absorption Coefficient ◽  
Electron Energy ◽  
Energy State ◽  
Total Absorption ◽  
Absorption Coefficients ◽  
Third Order ◽  
Index Changes ◽  
Total Absorption Coefficient

Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes’ range ensuring p-like Γ-electron energy state to be lower than s-like L-electron energy state. The results show strong dependence of the total absorption coefficient and refractive index changes on the quantum dot sizes. The third order nonlinear contribution is found to be sensitive to the incident light intensity affecting both total absorption coefficient and refractive index changes, especially for larger dot sizes.

scholarly journals Gamma?Radiation Absorption Coefficients of Various Materials Allowing for Bremsstrahlung and Other Secondary Radiations

1961 ◽  
Vol 14 (4) ◽  
pp. 443 ◽  
Author(s):  
JW Allison
Keyword(s):  
Absorption Coefficient ◽  
Energy Loss ◽  
Basic Assumption ◽  
Radiation Energy ◽  
Radiation Absorption ◽  
Annihilation Radiation ◽  
Total Absorption ◽  
Absorption Coefficients ◽  
Radiation Energy Loss ◽  
Total Absorption Coefficient

Existing calculations of the total absorption coefficient are generally based on the assumption that all the primary radiation energy which is converted into Comptonscattered radiation escapes from the material without significant absorption. This paper extends this basic assumption to include fluorescent and annihilation radiation and bremsstrahlung, and new values of the photoelectric, Compton, pair production, and total absorption coefficients are determined in the energy range O� 01-100 MeV for hydrogen, nitrogen, oxygen, argon, aluminium, iron, lead, air, and water. For comparison purposes revised values of the total absorption coefficient, allowing for the Compton radiation energy loss only, are also determined for these materials, using the most recent data for the component coefficients.

Measurement of the Total Absorption Coefficient of Long-Lived NeutralKParticles

1958 ◽  
Vol 109 (4) ◽  
pp. 1353-1357 ◽  
Author(s):  
W. K. H. Panofsky ◽  
V. L. Fitch ◽  
R. M. Motley ◽  
W. G. Chesnut
Keyword(s):  
Absorption Coefficient ◽  
Total Absorption ◽  
Total Absorption Coefficient

Remote Sensing Retrieval and Hourly Variation Analysis of Total Absorption Coefficient in the Bohai Sea with Geostationary Ocean Color Imager

2016 ◽  
Vol 36 (4) ◽  
pp. 0401003
Author(s):  
牟冰 Mu Bing ◽  
崔廷伟 Cui Tingwei ◽  
秦平 Qin Ping ◽  
刘荣杰 Liu Rongjie ◽  
郑荣儿 Zheng Ronger
Keyword(s):  
Remote Sensing ◽  
Absorption Coefficient ◽  
Bohai Sea ◽  
Ocean Color ◽  
Total Absorption ◽  
Variation Analysis ◽  
The Bohai Sea ◽  
Hourly Variation ◽  
Total Absorption Coefficient

Quantitative Ausmessung des Fluor-Affinitätskontinuums

1967 ◽  
Vol 22 (2) ◽  
pp. 254-259 ◽  
Author(s):  
Hanns-Peter Popp
Keyword(s):  
Absorption Coefficient ◽  
Cross Section ◽  
Photon Energy ◽  
Temperature Measurements ◽  
Total Absorption ◽  
Long Wavelength ◽  
Continuous Background ◽  
Total Absorption Coefficient ◽  
The Continuum ◽  
Kirchhoff's Law

The radiation emitted from a cylindric arc burning in SF6-gas at low currents shows the affinitycontinuum of fluorine with a long wavelength threshold of 3646 A. By means of spectroscopic temperature measurements and using KIRCHHOFF’s law the total absorption coefficient for the continuum in the range from 6800 to 2600 A is obtained. Isolating the F-affinity-continuum from the continuous background, the detachment cross section of the negative fluorine ion is obtained as a function of the photon energy.

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