Limits...
An effective method for substance detection using the broad spectrum THz signal with a "terahertz nose".

Trofimov VA, Varentsova SA - Sensors (Basel) (2015)

Bottom Line: This pulse excites, for example, many vibrational or rotational energy levels of molecules simultaneously.Comparing the absorption and emission spectrum dynamics of a substance under analysis with the corresponding data for a standard substance, one can detect and identify the substance under real conditions taking into account the influence of packing material, water vapor and substance surface.For quality assessment of the standard substance detection in the signal under analysis, we propose time-dependent integral correlation criteria.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University, Leninskiye Gory, Moscow 119992, Russia;. vatro@cs.msu.ru.

ABSTRACT
We propose an effective method for the detection and identification of dangerous substances by using the broadband THz pulse. This pulse excites, for example, many vibrational or rotational energy levels of molecules simultaneously. By analyzing the time-dependent spectrum of the THz pulse transmitted through or reflected from a substance, we follow the average response spectrum dynamics. Comparing the absorption and emission spectrum dynamics of a substance under analysis with the corresponding data for a standard substance, one can detect and identify the substance under real conditions taking into account the influence of packing material, water vapor and substance surface. For quality assessment of the standard substance detection in the signal under analysis, we propose time-dependent integral correlation criteria. Restrictions of usually used detection and identification methods, based on a comparison between the absorption frequencies of a substance under analysis and a standard substance, are demonstrated using a physical experiment with paper napkins.

No MeSH data available.


Related in: MedlinePlus

Integral characteristics detecting the frequencies ν = 1.16 THz (a); 1.4 THz (b) in the time interval t = [40, 65] ps; ν = 1.15 THz (a1); 1.4 THz (b1) in the time interval t = [70, 170] ps.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4507671&req=5

sensors-15-12103-f028: Integral characteristics detecting the frequencies ν = 1.16 THz (a); 1.4 THz (b) in the time interval t = [40, 65] ps; ν = 1.15 THz (a1); 1.4 THz (b1) in the time interval t = [70, 170] ps.

Mentions: In Figure 28 the integral characteristic CWp,P(tn) detects the frequency ν = 1.16 THz in the interval t = [40, 65] ps (Figure 28a), ν =1.15 THz—in the remote interval t = [70, 170] ps (Figure 28a1). The frequency ν = 1.4 THz is detected in both time intervals (Figure 28b,b1). Note that the reasons for the detection in both cases are different—the influence of the water molecules on the concave surface during the first sub-pulse and the influence of the environment in the remote part of the signal.


An effective method for substance detection using the broad spectrum THz signal with a "terahertz nose".

Trofimov VA, Varentsova SA - Sensors (Basel) (2015)

Integral characteristics detecting the frequencies ν = 1.16 THz (a); 1.4 THz (b) in the time interval t = [40, 65] ps; ν = 1.15 THz (a1); 1.4 THz (b1) in the time interval t = [70, 170] ps.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507671&req=5

sensors-15-12103-f028: Integral characteristics detecting the frequencies ν = 1.16 THz (a); 1.4 THz (b) in the time interval t = [40, 65] ps; ν = 1.15 THz (a1); 1.4 THz (b1) in the time interval t = [70, 170] ps.
Mentions: In Figure 28 the integral characteristic CWp,P(tn) detects the frequency ν = 1.16 THz in the interval t = [40, 65] ps (Figure 28a), ν =1.15 THz—in the remote interval t = [70, 170] ps (Figure 28a1). The frequency ν = 1.4 THz is detected in both time intervals (Figure 28b,b1). Note that the reasons for the detection in both cases are different—the influence of the water molecules on the concave surface during the first sub-pulse and the influence of the environment in the remote part of the signal.

Bottom Line: This pulse excites, for example, many vibrational or rotational energy levels of molecules simultaneously.Comparing the absorption and emission spectrum dynamics of a substance under analysis with the corresponding data for a standard substance, one can detect and identify the substance under real conditions taking into account the influence of packing material, water vapor and substance surface.For quality assessment of the standard substance detection in the signal under analysis, we propose time-dependent integral correlation criteria.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University, Leninskiye Gory, Moscow 119992, Russia;. vatro@cs.msu.ru.

ABSTRACT
We propose an effective method for the detection and identification of dangerous substances by using the broadband THz pulse. This pulse excites, for example, many vibrational or rotational energy levels of molecules simultaneously. By analyzing the time-dependent spectrum of the THz pulse transmitted through or reflected from a substance, we follow the average response spectrum dynamics. Comparing the absorption and emission spectrum dynamics of a substance under analysis with the corresponding data for a standard substance, one can detect and identify the substance under real conditions taking into account the influence of packing material, water vapor and substance surface. For quality assessment of the standard substance detection in the signal under analysis, we propose time-dependent integral correlation criteria. Restrictions of usually used detection and identification methods, based on a comparison between the absorption frequencies of a substance under analysis and a standard substance, are demonstrated using a physical experiment with paper napkins.

No MeSH data available.


Related in: MedlinePlus