Variations of spectral intensities by metastable nitrogen molecules in glow discharges excited in N2 and Ar+N2

1972 ◽  
Vol 22 (1) ◽  
pp. 93-95
Author(s):  
J. Janča ◽  
A. Tálský
1988 ◽  
Vol 102 ◽  
pp. 329
Author(s):  
R.W.P. McWhirter

The intensity of a specrtal line from an optically thin plasma such as the outer atmosphere of the sun depends on both the atomic properties of the atomic ion responsible for the line and the physical nature of the plasma. In this paper we discuss the various ways in which the measured spectral intensities from the sun are used to discover something about the nature of the sun’s atmosphere. The technique has been referred to as the emission measure method. It has important limitations in terms of the accuracy of the specrtal data as well as the atomic data. We discuss some of these and suggest methods by which they may be assessed. The technique is illustrated by application to real observations from a number of authors.


1988 ◽  
Vol 49 (C1) ◽  
pp. C1-329-C1-329 ◽  
Author(s):  
R. W.P. McWHIRTER
Keyword(s):  

2000 ◽  
Author(s):  
Azer Yalin ◽  
Yuriy Ionikh ◽  
Alexander Meshchanov ◽  
Richard Miles

2021 ◽  
pp. 000370282110123
Author(s):  
Hemalaxmi Rajavelu ◽  
Nilesh J Vasa ◽  
Satyanarayanan Seshadri

A benchtop Laser-Induced Breakdown Spectroscopy (LIBS) is demonstrated to determine the elemental carbon content present in raw coal used for combustion in power plants. The spectral intensities of molecular CN and C2 emission are measured together with the atomic carbon (C) and other inorganic elements (Si, Fe, Mg, Al, Ca, Na, and K) in the LIBS spectrum of coal. The emission persistence time of C2 molecule emission is measured from the coal plasma generated by a nanosecond laser ablation with a wavelength of 266 nm in the Ar atmosphere. The emission persistence time of molecular C2 emission along with the spectral intensities of major ash elements (Fe, Si, Al, and Ca) and carbon emissions (atomic C, molecular CN, and C2) shows a better relationship with the carbon wt% of different coal samples. The calibration model to measure elemental carbon (wt%) is developed by combining the spectral characteristics (Spectral intensity) and the temporal characteristics (Emission persistence time of C2 molecule emission). The temporal characteristic studies combined with the spectroscopic data in the PLSR (Partial Least Square Regression) model has resulted in an improvement in the root mean square error of validation (RMSEV), and the relative standard deviation (RSD) is reduced from 10.86% to 4.12% and from 11.32% to 6.04%, respectively.


Vacuum ◽  
1991 ◽  
Vol 42 (1-2) ◽  
pp. 33-34 ◽  
Author(s):  
R Deltchev ◽  
M Albert ◽  
G Suchaneck ◽  
K Schade

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2365 ◽  
Author(s):  
Vyacheslav A. Trofimov ◽  
Svetlana A. Varentsova

We discuss an effective tool for the detection and identification of substances in ternary mixtures with similar spectral properties using a broadband reflected THz signal. Nowadays, this is an urgent problem; its effective solution is still far off. Two ternary mixtures of the explosives (RDX+TNT+HMX and RDX+TNT+PETN) were used as the examples for demonstration of the efficiency of the method proposed. The identification is based on the pulsed THz spectroscopy. We follow the spectral intensities together with the use of integral correlation criteria. They use the spectral line dynamics of the THz pulse reflected from the substance under investigation and that of the standard THz signal from database. In order to increase the accuracy and reliability of the identification, we analyze the partial non-overlapping time intervals, containing the main pulse of the reflected THz signal and the sequential sub-pulses. The main pulse is shown to contain information about high absorption frequencies (ν > 2.6 THz) of the mixture components. In the sub-pulses, the absorption frequencies of the components are detected in the range of low (ν < 2.6 THz) and high (ν > 2.6 THz) frequencies. The opportunity of distinguishing the mixtures with similar spectral properties is also shown.


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