The Identification of Molecular Spectra

Pearse, R. W. B.; Gaydon, A. G.

doi:10.1007/978-94-009-5758-9

Cited by 1,196 publications

(763 citation statements)

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“…No water-derived compounds such as OH, however, were spectrally observed, although strong OH bands are located in a much shorter wavelength range than the current coverage [e.g., Pearse and Gaydon, 1976]. Further, no spectral signature of either air (e.g., O, N, O 2 , N 2 , NO, etc.)…”

Section: Spectral Contentmentioning

confidence: 81%

Interactions between impact‐induced vapor clouds and the ambient atmosphere: 1. Spectroscopic observations using diatomic molecular emission

Sugita

Schultz

2003

J. Geophys. Res.

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[1] The importance of interactions between impact-induced vapor clouds and an ambient atmosphere has been widely recognized, and theoretical approaches have provided significant insights. Few experiments, however, have been done to observe directly the energy partitioning during the interactions between impact vapor clouds and the ambient atmosphere. The present study attempts to understand the difference between actual and theoretical model impact vapor clouds produced under an atmosphere. A series of hypervelocity impact experiments was conducted using a spectroscopic measurement method. Plastic (polycarbonate) impactors allowed simulating vaporization phenomena associated with natural impactors (e.g., silicates and metals) at high impact velocities into water. Water as the target material served to suppress the effect of fine-grained fragments from the target. Emission spectra of the leading part of downrange-moving impact vapor clouds were captured with high-speed spectrometers as a function of time for various ambient pressures. The emission spectra exhibit strong molecular bands from carbon compounds as well as blackbody continuum radiation. In order to estimate the temperature of the radiation source, we carried out a spectral-form inversion analysis based on diatomic emission theory. Obtained molecular radiation temperatures range from 4500 K to 5500 K with relatively high accuracy ($2%) and place a number of well-defined constraints for the radiation source. A simple theoretical model that is often assumed for an impact-induced vapor cloud, however, does not readily satisfy the constraints. This strongly suggests that real impact-induced vapor clouds may be more complex than previously thought.INDEX TERMS: 5420 Planetology: Solid Surface Planets: Impact phenomena (includes cratering); 5407 Planetology: Solid Surface Planets: Atmospheres-evolution; 5455 Planetology: Solid Surface Planets: Origin and evolution; 5494 Planetology: Solid Surface Planets: Instruments and techniques; 6022 Planetology: Comets and Small Bodies: Impact phenomena; KEYWORDS: Impact cratering, impact experiments, impact vaporization, impact flash spectroscopy, molecular emission Citation: Sugita, S., and P. H. Schultz, Interactions between impact-induced vapor clouds and the ambient atmosphere: 1.

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Section: Spectral Contentmentioning

confidence: 81%

Interactions between impact‐induced vapor clouds and the ambient atmosphere: 1. Spectroscopic observations using diatomic molecular emission

Sugita

Schultz

2003

J. Geophys. Res.

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“…The CH peaks observed at 387 nm was under the 3900 A System ( 2 Σ → 2 π). 31) There are more CH fragments in the plasma discharge than in Ar=OD as can be seen from the relative intensity of the CH peaks, which were 0.04 and 0.03 for Ar=HMDSO and Ar=OD, respectively. Under a pure Ar discharge, no CH band was observed as expected.…”

Section: Optical Emission Spectroscopymentioning

confidence: 91%

Improved Optical Degradation Characteristics of Eu Complex Encapsulated by High-Pressure Annealing

Kato¹,

Fukuda²,

Akiyama³

et al. 2011

Jpn. J. Appl. Phys.

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In this study, we explored the use of rice-husk-derived nanosilica (nSiO 2 ) as fillers in epoxy resins. The nSiO 2 was irradiated with a capacitively coupled 13.56 MHz radio frequency (RF) plasma using an admixture of argon (Ar) and hexamethyldisiloxane (HMDSO) or 1,7-octadiene (OD) monomers. The plasma-polymerized nSiO 2 was loaded at various concentrations (1-5%) into the epoxy matrix. Surface hydrophobicity of the plasma-treated nSiO 2 -filled composites increased, which is attributed to the attachment of functional groups from the monomer gases on the silica surface. Microhardness increased by at least 10% upon the inclusion of plasma-modified nSiO 2 compared with pristine nSiO 2 -epoxy composites. Likewise, hardness increased with increasing loading volume, with the HMDSO-treated silica composite recording the highest increase. Elastic moduli of the composites also showed an increase of at least 14% compared with untreated nSiO 2 -filled composites. This work demonstrated the use of rice husk, an agricultural waste, as a nSiO 2 source for epoxy resin fillers.

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“…1b). Images of the (1, 0) C 2 Swan band (at a wavelength of 473 nm [22]) are obtained using an ITT F4577 intensified 513 ϫ 480 pixel camera through a narrow wavelength interference filter (470 Ϯ 10 nm), and transferred to a frame grabber and processed by subtracting a representative background image. The emission can be interpreted as a signature of chemical reaction and heat release [23][24][25][26], since the excited C* 2 free radical species is short-lived, a good indicator of the reaction zone [25], and its light intensity is known to vary linearly with the volumetric heat release [13,26].…”

Section: Methodsmentioning

confidence: 99%

00/00985 Gravity effects on steady two-dimensional partially premixed methane-air flames

2000

Fuel and Energy Abstracts

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Under normal-gravity conditions the flame heat release produces both flow dilatation and buoyancy effects. While it may be possible to minimize gravitational effects in a fully premixed flame by isolating buoyancy effects to the lower-density postflame region or plume, this cannot be accomplished in nonpremixed flames. It is known that partially premixed flames can contain two reaction zones, one with a premixed-like structure and the other consisting of a transport-limited nonpremixed zone (in which mixing and entrainment effects are significant). For these reasons it is important to understand the fundamental interaction between flow dilatation and buoyancy effects in partially premixed flames. A detailed numerical study is conducted to characterize the effect of buoyancy on the structure of two-dimensional partially premixed methane-air flames. The computational model is validated by comparison with the experimentally obtained chemiluminescent emission from excited-C* 2 free radical species as well as with velocity vectors obtained using particle image velocimetry. Both the experiments and simulations indicate the presence of two reaction zones that are synergistically coupled, with each region providing heat and/or chemical species for the other. While the inner premixed flame is only weakly affected by gravity, the outer flame shows significant spatial differences for the two cases due to buoyancyinduced entrainment, since advection of air into the outer reaction zone increases in the presence of gravity. The presence of gravity induces more compact flames, influences the velocity profiles in the post-inner flame region, and increases the normal strain rate. Although the spatial differences between the 0-and 1-g flames are more significant on the lean side, the state relationships in that region are relatively unaffected by gravity. On the other hand, the inner (rich-side) reaction zone shifts toward less-rich locations in the presence of gravity, possibly due to the enhanced buoyant mixing. The 1-g flames exhibit a larger energy loss in the form of CO and H 2 emissions.

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The Identification of Molecular Spectra

Cited by 1,196 publications

References 0 publications

Interactions between impact‐induced vapor clouds and the ambient atmosphere: 1. Spectroscopic observations using diatomic molecular emission

Interactions between impact‐induced vapor clouds and the ambient atmosphere: 1. Spectroscopic observations using diatomic molecular emission

Improved Optical Degradation Characteristics of Eu Complex Encapsulated by High-Pressure Annealing

00/00985 Gravity effects on steady two-dimensional partially premixed methane-air flames

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