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: We propose an effective method for the detection and identification of dangerous substances by using the broadband THz pulse.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.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.

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

Fourier spectra (a) and reflectance (b) of the main pulses S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 and PWM signals [28].
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-12103-f022: Fourier spectra (a) and reflectance (b) of the main pulses S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 and PWM signals [28].

Mentions: In Figure 22 the Fourier spectra (Figure 22a) and reflectance (Figure 22b) of the main pulse S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 signals and smooth PWM are presented. Note that the spectral amplitudes in (Figure 22a) and the reflectance in (Figure 22b) of PWM_0.5, 1.0, 1.5 signals are much less than the spectral amplitude and reflectance of the smooth PWM signal, and the shape of spectra and reflectance of concave PWM signals in Figure 22a,b differs from that of the smooth PWM signal. Therefore, as in the case of the rough PWM_40, PWM_80 and PWM_120 signals, a concave surface also distorts the spectral properties of the main pulses of the PWM_0.5, PWM_1.0, PWM_1.5 signals and they cannot be used for identification.


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

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

Fourier spectra (a) and reflectance (b) of the main pulses S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 and PWM signals [28].
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-12103-f022: Fourier spectra (a) and reflectance (b) of the main pulses S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 and PWM signals [28].
Mentions: In Figure 22 the Fourier spectra (Figure 22a) and reflectance (Figure 22b) of the main pulse S0(t) of the PWM_0.5, PWM_1.0, PWM_1.5 signals and smooth PWM are presented. Note that the spectral amplitudes in (Figure 22a) and the reflectance in (Figure 22b) of PWM_0.5, 1.0, 1.5 signals are much less than the spectral amplitude and reflectance of the smooth PWM signal, and the shape of spectra and reflectance of concave PWM signals in Figure 22a,b differs from that of the smooth PWM signal. Therefore, as in the case of the rough PWM_40, PWM_80 and PWM_120 signals, a concave surface also distorts the spectral properties of the main pulses of the PWM_0.5, PWM_1.0, PWM_1.5 signals and they cannot be used for identification.

Bottom Line: We propose an effective method for the detection and identification of dangerous substances by using the broadband THz pulse.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.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.

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