scholarly journals TIME-DEPENDENT FISSION-PRODUCT THERMAL AND RESONANCE ABSORPTION CROSS SECTIONS

1962 ◽  
Author(s):  
T. R. England
Keyword(s):  
Fission Product ◽  
Cross Sections ◽  
Resonance Absorption ◽  
Time Dependent ◽  
Absorption Cross

Effect of Time-Dependent Ionization on Dynamical Two-Photon Absorption Cross Sections of Molecular Media

2009 ◽  
Vol 29 (6) ◽  
pp. 1621-1625 ◽  
Author(s):  
孙玉萍 Sun Yuping ◽  
刘纪彩 Liu Jicai ◽  
王传奎 Wang Chuankui
Keyword(s):  
Cross Sections ◽  
Time Dependent ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Two Photon

Spectroscopy Fundamentals

2017 ◽  
Author(s):  
Kelly Chance ◽  
Randall V. Martin
Keyword(s):  
Vibrational Spectroscopy ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Electronic Spectroscopy ◽  
Rotational Spectroscopy ◽  
Absorption Cross ◽  
Transfer Processes ◽  
Atmospheric Spectroscopy ◽  
Quantitative Spectroscopy ◽  
Broad Overview

This chapter provides a broad overview of the spectroscopic principles required in order to perform quantitative spectroscopy of atmospheres. It couples the details of atmospheric spectroscopy with the radiative transfer processes and also with the assessment of rotational, vibrational, and electronic spectroscopic measurements of atmospheres. The principles apply from line-resolved measurements (chiefly microwave through infrared) through ultraviolet and visible measurements employing absorption cross sections developed from individual transitions. The chapter introduces Einstein coefficients before in turn discussing rotational spectroscopy, vibrational spectroscopy, nuclear spin, and electronic spectroscopy.

scholarly journals Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

2021 ◽  
pp. 000370282199044
Author(s):  
Wubin Weng ◽  
Shen Li ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Elevated Temperatures ◽  
Uv Absorption ◽  
Energy Utilization ◽  
Quantitative Detection ◽  
Absorption Cross ◽  
Hot Gas

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the [Formula: see text] transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

Measurement of the scattering and absorption cross sections of the human body

2004 ◽  
Vol 84 (5) ◽  
pp. 819-821 ◽  
Author(s):  
Stéphane G. Conti ◽  
Philippe Roux ◽  
David A. Demer ◽  
Julien de Rosny
Keyword(s):  
Cross Sections ◽  
Human Body ◽  
Absorption Cross
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