scholarly journals Stability analysis and absorption cross section in three-dimensional black string

1998 ◽  
Vol 57 (12) ◽  
pp. 7361-7368 ◽  
Author(s):  
H. W. Lee ◽  
N. J. Kim ◽  
Y. S. Myung ◽  
Jin Young Kim
Keyword(s):  
Stability Analysis ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Three Dimensional ◽  
Absorption Cross ◽  
Black String

scholarly journals Absorption Cross Section and Decay Rate of Dilatonic Black Strings

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Huriye Gürsel ◽  
İzzet Sakallı
Keyword(s):  
Scalar Field ◽  
Decay Rate ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Gordon Equation ◽  
Absorption Cross ◽  
Black String ◽  
Yang Mills ◽  
Klein Gordon ◽  
Analytical Expressions

We studied in detail the propagation of a massive tachyonic scalar field in the background of a five-dimensional (5D) Einstein–Yang–Mills–Born–Infeld–dilaton black string: the massive Klein–Gordon equation was solved, exactly. Next we obtained complete analytical expressions for the greybody factor, absorption cross section, and decay rate for the tachyonic scalar field in the geometry under consideration. The behaviors of the obtained results are graphically represented for different values of the theory’s free parameters. We also discuss why tachyons should be used instead of ordinary particles for the analytical derivation of the greybody factor of the dilatonic 5D black string.

scholarly journals ABSORPTION CROSS-SECTION IN DE SITTER SPACE

2003 ◽  
Vol 18 (09) ◽  
pp. 617-628 ◽  
Author(s):  
Y. S. MYUNG
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Three Dimensional ◽  
De Sitter Space ◽  
Temperature Limit ◽  
Low Energy ◽  
Massless Scalar ◽  
Cosmological Horizon ◽  
Absorption Cross ◽  
De Sitter

We study the wave equation for a minimally coupled massive scalar in three-dimensional de Sitter space. We compute the absorption cross-section to investigate its cosmological horizon in the southern diamond. Although the absorption cross-section is not defined exactly, it can be determined from the fact that the low-energy s(j = 0)-wave absorption cross-section for a massless scalar is given by the area of the cosmological horizon. On the other hand, the low-temperature limit of j ≠ 0-mode absorption cross-section is useful for extracting information surrounding the cosmological horizon. Finally we mention a computation of the absorption cross-section on the CFT-side using the dS/CFT correspondence.

scholarly journals Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025120
Author(s):  
C. Stanford ◽  
M. J. Wilson ◽  
B. Cabrera ◽  
M. Diamond ◽  
N. A. Kurinsky ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Room Temperature ◽  
Absorption Cross ◽  
Photoelectric Absorption

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.

Sign in / Sign up

Export Citation Format

Share Document