Light absorption coefficient in plasma

1974 ◽  
Vol 21 (3) ◽  
pp. 1161-1164
Author(s):  
G. S. Romanov ◽  
L. K. Stanchits ◽  
F. N. Borovik
Keyword(s):  
Absorption Coefficient ◽  
Light Absorption ◽  
Light Absorption Coefficient

Particulate light absorption and the prediction of phytoplankton biomass and planktonic metabolism in northeastern Spanish aquatic ecosystems

2000 ◽  
Vol 57 (1) ◽  
pp. 25-33 ◽  
Author(s):  
C M Duarte ◽  
S Agustí ◽  
J Kalff
Keyword(s):  
Absorption Coefficient ◽  
Light Absorption ◽  
Aquatic Ecosystems ◽  
Coastal Lagoons ◽  
Strong Relationship ◽  
Community Respiration ◽  
Chl A ◽  
Light Absorption Coefficient ◽  
Alpine Rivers ◽  
Detrital Particles

Examination of particulate light absorption and microplankton metabolism in 36 northeastern Spanish aquatic ecosystems, ranging from alpine rivers to inland saline lakes and the open Mediterranean Sea, revealed the existence of general relationships between particulate light absorption and the biomass of phytoplankton and microplankton metabolism. The particulate absorption spectra reflected a dominance of nonphotosynthetic, likely detrital, particles in rivers and a dominance of phytoplankton in coastal lagoons. There was a strong relationship between the light absorbed by phytoplankton and the chlorophyll a (Chl a) concentration of the systems, which indicated an average (±SE) Chl a specific absorption coefficient of 0.0233 ± 0.0020 m2·mg Chl a-1 for these widely diverse systems. Chl a concentration was a weaker predictor of the total particulate light absorption coefficient, pointing to an important role of nonphytoplanktonic particles in light absorption. Gross production was very closely related to the light absorption coefficient of phytoplankton, whereas community respiration was strongly correlated with the total particulate light absorption coefficient, indicating the optical signatures of sestonic particles to be reliable predictors of planktonic biomass and metabolism in aquatic ecosystems.

Traffic and seasonal dependence of the light absorption coefficient in Santiago de Chile

2000 ◽  
Vol 39 (27) ◽  
pp. 4895 ◽  
Author(s):  
Ernesto Gramsch ◽  
Luis Catalán ◽  
Isabel Ormeño ◽  
Guillermo Palma
Keyword(s):  
Absorption Coefficient ◽  
Light Absorption ◽  
Santiago De Chile ◽  
Light Absorption Coefficient ◽  
Seasonal Dependence

scholarly journals The Effect of Carbon Defects in the Coal–Pyrite Vacancy on the Electronic Structure and Optical Properties: A DFT + U Study

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 815
Author(s):  
Wei Cheng ◽  
Chen Cheng ◽  
Baolin Ke
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Absorption Coefficient ◽  
Light Absorption ◽  
Density Functional ◽  
Doping Concentration ◽  
Carbon Doping ◽  
Photovoltaic Materials ◽  
Light Absorption Coefficient ◽  
Carbon Impurities

Pyrite is a mineral often associated with coal in coal seams and is a major source of sulfur in coal. Coal–pyrite is widely distributed, easily available, low-cost, and non-toxic, and has high light absorption coefficient. So, it shows potential for various applications. In this paper, the density-functional theory (DFT + U) is used to construct coal–pyrite with carbon doped in the sulfur and iron vacancies of pyrite. The effects of different carbon defects, different carbon doping concentrations, and different doping distributions in the same concentration on the electronic structure and optical properties of coal–pyrite were studied. The results show that the absorption coefficient and reflectivity of coal–pyrite, when its carbon atom substitutes the iron and sulfur atoms in the sulfur and iron vacancies, are significantly higher than those of the perfect pyrite, indicating that coal–pyrite has potential for application in the field of photovoltaic materials. When carbon is doped in the sulfur vacancy, this impurity state reduces the width of the forbidden band; with the increase in the doping concentration, the width of the forbidden band decreases and the visible-light absorption coefficient increases. The distribution of carbon impurities impacts the band gap but has almost no effect on the light absorption coefficient, complex dielectric function, and reflectivity, indicating that the application of coal–pyrite to photovoltaic materials should mainly consider the carbon doping concentration instead of the distribution of carbon impurities. The research results provide a theoretical reference for the application of coal–pyrite in the field of photoelectric materials.

Comparison of Two Filter-Based Reflectance Methods to Measure the Light Absorption by Atmospheric Aerosols

2014 ◽  
Vol 31 (4) ◽  
pp. 923-929 ◽  
Author(s):  
Rudra Aryal ◽  
Paul Terman ◽  
Kenneth J. Voss
Keyword(s):  
Absorption Coefficient ◽  
Atmospheric Aerosols ◽  
Light Absorption ◽  
Aerosol Particles ◽  
Sampling Scheme ◽  
Sampling Area ◽  
Aerosol Absorption ◽  
Light Absorption Coefficient ◽  
M Theory ◽  
Full Day

Abstract Two reflectance techniques, based on Kubelka–Munk (K-M) theory and on the Beer–Lambert (B-L) law, were used to measure the absorption coefficient of aerosol particles collected on a filter. The two methods agreed, with the B-L technique being higher than the K-M method by a factor of 1.10, but with a correlation, r2, between the two methods of 0.99. The aerosol absorption Ångström exponents (AAE) between the two methods also agreed within 0.4 and were in the range of measurements reported in the literature with other techniques. The precision of the two methods depends on the volume of air sampled, but a typical sampling scheme (100 L min−1, 10 cm2 sampling area, full day of sampling) results in a precision in the measurement of the aerosol light absorption coefficient of 0.05 Mm−1.

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