Scattering Properties of Concentric Soot–Water Spheres for Visible and Infrared Light

Fenn, Robert W.; Oser, Hansjörg

doi:10.1364/ao.4.001504

Cited by 69 publications

(24 citation statements)

References 2 publications

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“…A similar but more important impact than for soot particles is found. This could be explained by the coarser size of dust particles, which enhances the coating effects [Fenn and Oser, 1965]. The impact of a water shell on organic carbon particles was also checked.…”

Section: Results Inmentioning

confidence: 99%

“…Second, the particle size distribution also influences aerosol optical properties, as shown by theoretical studies on scattering and absorbing cross sections, the single scattering albedo, and the backscattering parameters [e.g., Fenn and Oser, 1965]. Third, considering external or internal mixing for the aerosol phase also changes the aerosol optical properties.…”

Section: Tests On Aerosol Models the Optical Properties Of The Aementioning

confidence: 99%

See 1 more Smart Citation

Remote sensing of carbonaceous aerosol production by African savanna biomass burning

Liousse¹,

Dulac²,

Cachier³

et al. 1997

J. Geophys. Res.

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Abstract. We present an estimate of the yearly flux of total and black carbon aerosols emitted by savanna biomass burning in Africa from satellite data and ground-based measurements. Smoke plumes are identified using visible, near-infrared, and thermal infrared derived information. In the savanna region of our study, these structures could either decrease or increase the visible albedo of advanced very high resolution radiometer (AVHRR). It is hypothesized that variations of chemical composition and particulate size distribution may create such differences. The 5S model [Tanr• et al., 1990] is used to simulate radiative transfer through smoke plumes and background atmosphere. The overall uncertainty of the derived aerosol optical depth ('•,) is 75% and mainly due to the choice in particulate composition and size distribution aerosol. Impact of the aerosol mixture (internal versus external mixture) has been also tested. For smoke plumes a typical value of x, (at 0.55 gm) is 0.5, and 0.1 for the background atmosphere. Specific extinction cross sections are calculated using Mie theory applied to different representative aerosol models, allowing the retrieval of aerosol columnar concentrations from aerosol optical depth values and integrated aerosol mass loadings in fire plumes. The overall uncertainty on the determination of aerosol load is estimated to be lower than a factor of 5. The atmospheric carbonaceous aerosol flux from savanna burning in Africa was estimated to be 6.5 Tg C yr -•, which compares with that obtained from emission factor on-site measurements (13 _+ 5 Tg C yr'•).

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Section: Results Inmentioning

confidence: 99%

Section: Tests On Aerosol Models the Optical Properties Of The Aementioning

confidence: 99%

Remote sensing of carbonaceous aerosol production by African savanna biomass burning

Liousse¹,

Dulac²,

Cachier³

et al. 1997

J. Geophys. Res.

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“…1) may easily be separated into absorption and scattering contributions: CD8u,, = CDabs + CDscat (6 (22) and absorbing coat (21), as well as nonabsorbing dielectric coated spheres (23). Agreement was achieved in all cases.…”

mentioning

confidence: 77%

Circular Dichroism of Chromaffin Granule Proteins In Situ: Analysis of Turbidity Effects and Protein Conformation

Rosenheck¹,

Schneider²

1973

Proc. Natl. Acad. Sci. U.S.A.

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The circular dichroism spectra for proteins in situ in catecholamine secretory vesicles (chromaffin granules) is presented together with an analysis of protein conformation and turbidity effects on the spectra. The calculational analysis has resolved scattering and absorption effects in the turbid suspension spectra using a coated-sphere scattering model which allows for different materials in its shell and core. The intrinsic conformation of the proteins in situ was estimated by an iterative procedure with various trial protein conformations, for the chromaffin granules both intact and after release of their contents. The resulting average secondary structures (within about 10%) are: (25% a helix, 15% ,6 structure) for the membrane proteins and (15% a helix, 5% # structure) for the soluble contents. The protein conformation did not change with osmotic release of the granule's contents. Consequently, if chromogranins are involved in a catecholamine storage complex, this is not reflected in any detectable change in their average secondary structure.Circular dichroism (CD) and optical rotatory dispersion (ORD) have proven very useful in monitoring protein and nucleic-acid conformations in solution. While the solution work has laid important groundwork for the structural interpretation of the spectra, it is the study of biopolymers in situ in functioning biological complexes that is of ultimate interest for elucidation of cellular processes. In the last few years a beginning has been made in this direction, primarily for turbid suspensions of biological membranes (1). The membrane CD and ORD spectra contain characteristic distortions in the shape and magnitude of the spectral bands, and these were experimentally shown to be caused by the scattering properties and particulate nature of the membrane suspension (1-4). Similar results were found for turbid suspensions of hemoglobin within erythrocytes (1) and for polypeptide aggregates (3). Thus, in order to interpret the spectra of such turbid suspensions, the scattering contributions had to be resolved. A theoretical analysis of the circular polarization dependence of scattered light followed (5) and formed the basis for a calculational method of analyzing distorted spectra (6). Numerical computations using this approach have appeared (7,8)

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“…The outer radius of the particle is still a, and the outer layer still has material properties 2 and µ 2 , but this medium surrounds a core of radius b and material parameters 3 , µ 3 . Of the references cited above, only [30] gives expressions for the modified Lorenz-Mie coefficients of a two-layer sphere when there is contrast in the magnetic properties as well as the dielectric ones (these results can be found quoted elsewhere, in [33] and [34] for example). Their results can be written in our notation as: where…”

Section: Array Of Two-layered Spheres -Critical Analysismentioning

confidence: 99%

A Negative Refractive Index Metamaterial Based on a Cubic Array of Layered Nonmagnetic Spherical Particles

Kuester¹,

Memic²,

Shen³

et al. 2011

PIER B

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Abstract-A low-loss passive metamaterial exhibiting negative refractive index or "double negative" electromagnetic properties at microwave frequencies is proposed. The metamaterial is a lattice of spherical particles made up of multiple dielectric materials in concentric layers. Because no magnetic constituents (that tend to have higher losses) are involved, the negative-index behavior is possible with very low values of attenuation. A negative-index metamaterial based on dielectric-coated metal spheres is also proposed, and is predicted to have lower attenuation than other structures based on metallic scatterers. Numerical results and design principles are given.

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Scattering Properties of Concentric Soot–Water Spheres for Visible and Infrared Light

Cited by 69 publications

References 2 publications

Remote sensing of carbonaceous aerosol production by African savanna biomass burning

Remote sensing of carbonaceous aerosol production by African savanna biomass burning

Circular Dichroism of Chromaffin Granule Proteins In Situ: Analysis of Turbidity Effects and Protein Conformation

A Negative Refractive Index Metamaterial Based on a Cubic Array of Layered Nonmagnetic Spherical Particles

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