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Wyszukujesz frazę "Palka, N." wg kryterium: Autor


Tytuł:
Extension of the p-Spectrum Method to the Higher Frequencies
Autorzy:
Pałka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1399394.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
78.20.Ci
78.40.-q
78.47.jg
Opis:
The p-spectrum method is a time domain spectroscopy-based technique for reflection analysis of materials (including explosives) that takes into account only part of the reflected signal, which is next analyzed via the Fourier transform. The method is limited to the frequencies of about 1.8 THz due to the pulse properties of our time domain spectroscopy setup. In this paper we theoretically prove that application of a shorter pulse can increase this frequency range up to 2.2 THz, that enables analysis of penthrite and octogen, two important explosives.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 534-537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THz Reflection Spectroscopy of Explosives Measured by Time Domain Spectroscopy
Autorzy:
Palka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1493255.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
07.57.Pt
78.20.Ci
78.40.Pg
Opis:
Reflection spectra of pure explosive materials and their simulants were measured in transmission and reflection by means of time domain spectroscopy in the range 0.1-3 THz. Spectra measured in two reflection configurations: specular with incident angle equal to 45° and stand-off with close to normal incidence and distance 30 and 40 cm to samples was analyzed.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 713-715
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex THz Reflectance Spectra of Hexogen Measured for Various Surfaces
Autorzy:
Palka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1418028.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
78.20.Ci
78.40.Pg
78.40.-q
78.47.jg
Opis:
In this paper, we report on measurements of reflection spectra of hexogen (RDX) by means of time domain spectroscopy. We analyzed both phase and amplitude of reflected impulses for three cases: detuning, samples with rough surfaces and samples with curved surfaces. It can be concluded that both spectral characteristics can be applied for identification of explosives in the reflection configuration.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 854-857
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopy of Explosive Materials in the THz Range
Autorzy:
Palka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1506821.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
07.57.Pt
78.20.Ci
78.40.Pg
Opis:
Absorption spectra of hexogen and penthrite-2 commonly used explosive materials in the range 0.3-3 THz are presented. The measurements were carried out by means of time domain spectroscopy and compared to spectra obtained by Fourier transform infrared spectroscopy. Good conformity is observed.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1229-1231
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple method for characterization of photonic crystal fibers
Autorzy:
Szustakowski, M.
Pałka, N.
Grabiec, W.
Powiązania:
https://bibliotekanauki.pl/articles/308773.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
photonic crystal fibers
far field distribution
characterization
Opis:
We report on our experimental characterization of index-guiding photonic crystal fibers (PCF) from their far field intensity distribution. The algorithm presented below makes it possible to determine the geometrical parameters of the PCF (core diameter, air hole spacing and air hole diameter) from its far field pattern. We obtained good agreement with the manufacturer's data for all fibers tested.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 2; 109-113
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Focusing with 2D Square Photonic Crystal with Concavo-Concavo Boundaries
Autorzy:
Palka, N.
Ciurapinski, W.
Wróbel, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807741.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Qs
42.79.Bh
42.25.Bs
Opis:
We studied focusing properties of 2D square photonic crystal with concavo-concavo boundaries. The photonic crystal is built by air holes in a uniform dielectric. The incident plane wave propagates through a section of the photonic crystal and efficient focusing is observed by finite difference time domain simulations. To analyze the properties of photonic crystal we calculated the photonic band structure and equal frequency contours for TE modes. In our simulation we consider influence of geometry of the concave structures on the focusing properties.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 368-370
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz Frequency Domain Spectroscopy Identification System Based on Decision Trees
Autorzy:
Ryniec, R.
Zagrajek, P.
Pałka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1418036.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Bm
42.81.Cn
42.81.Dp
Opis:
The application of pattern recognition methodology within chemistry, biology and other science domains, especially in security systems is becoming more and more important. Many classification algorithms are available in literature but decision trees are the most commonly exploited because of their ease of implementation and understanding in comparison to other classification algorithms. Decision trees are powerful and popular tools for classification and prediction. In contrast to neural networks, decision trees represent rules, which can readily be expressed so that humans can understand them or even directly use in a database. In this paper we present an algorithm of construction of decision trees and a classification rule extraction based on a logical relationship between attributes and a generalized decision function. Moreover, correctness and efficiency of the algorithm was experimentally validated in a terahertz system, where spectra of explosives were measured in reflection configuration.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 891-895
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz Spectra of Explosives Measured by Optical Parametric Oscillator-Based System and Time Domain Spectroscopy
Autorzy:
Palka, N.
Trzcinski, T.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1418089.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
78.20.Ci
78.40.Pg
42.65.Yj
07.57.Kp
Opis:
In this paper, we report on measurements of absorption spectra of hexogen, penthrite, and octogen. The measurements were carried out by means of time domain spectroscopy and compared to spectra obtained from a setup, which bases on an optical parametric oscillator combined with a Golay cell. For time domain spectroscopy measurement, Teraview TPS 3000 unit with accessories in transmission configuration was used.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 946-949
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase coding of information in the optical fibre sensor
Autorzy:
Życzkowski, M.
Karol, M.
Pałka, N.
Powiązania:
https://bibliotekanauki.pl/articles/1818224.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
optical fibre sensors
Mach-Zehnder interferometer
quantum sensors
Opis:
Determining the dependence of phase difference modulations between light pulses in a modified Mach-Zehnder interferometer was used to develop an optical system coding the information and working as an eavesdropping sensor for an optical fibre information exchange system. The basic challenge in the system development is to maintain stable operation in changing environmental conditions, as well as to ensure optimal parameters of the phase modulator. The system was tested for various many-kilometer long transmission lines of single-mode fibres. The research was focused on achieving the normative Bit Error Rate for the system in the 100 Mbit/s range (STM-1). Such a system can be used in commercial applications for the code key secure transmission in the physical layer of the link.
Źródło:
Opto-Electronics Review; 2020, 28, 1; 1--7
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THz spectroscopy of explosive-related simulants and oxidizers
Autorzy:
Trzciński, T.
Palka, N.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200109.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
THz spectroscopy
explosive-related simulants
Opis:
In this paper we report on measurement of spectra of commonly applied explosives, some materials which can be used for manufacture of explosive and THz simulants of explosives in transmission mode. Substances were prepared as pellets, and the measurements were performed using the Time Domain Spectroscopy system in the range 0.1–3.0 THz.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 445-447
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hidden Object Detection System Based on Fusion of THz and VIS Images
Autorzy:
Kowalski, M.
Palka, N.
Piszczek, M.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399381.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Pj
42.30.Tz
02.60.-x
Opis:
Terahertz imaging makes it possible to acquire images of objects concealed underneath clothing by measuring the radiometric temperatures of different objects on a human subject. Finding objects hidden under clothes is one of key issues of public places security. A possible solution of this problem is a multispectral, terahertz-based screening system with implemented image fusion algorithm. The result of the fusion is a new image which gives more information and is more suitable for human perception. An imaging system is usually composed of various subsystems. Many of the imaging systems use imaging devices working in various spectral ranges. The aim of our studies is to detect and visualize objects hidden under clothing. Detection of potentially dangerous objects is important, but without proper visualization, can be difficult to utilize. Our goal is to build a system harmless to humans for screening and detection of hidden objects using a THz and VIS cameras. The presented system draws attention not only on the properties offered by a single camera but also on the potential of synergetic effects of the system by using the fusion of data registered by different sensor units. In this paper we present the multispectral passive imaging system for hidden threats visualization based on THz and VIS cameras.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 490-493
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupling in Core-Ring Photonic Crystal Fibers
Autorzy:
Palka, N.
Ciurapiński, W.
Wojcik, J.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1811539.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Bm
42.81.Cn
42.81.Dp
Opis:
Experimental investigations of light coupling from a core into a ring caused by microbendings in photonic crystal fibres are shown. We present a setup arrangement, mode fields with and without coupling and a plot of power transfer versus localisation of the modulator along the fibre. We also show the most probable explanation of the obtained data.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-157-A-161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THz Reflection Spectra of Different Materials, Including Explosives, Measured at a Distance up to 5 m
Autorzy:
Walczakowski, M.
Palka, N.
Czerwiński, A.
Sypek, M.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1398672.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
06.60.Ei
07.57.Hm
07.57.Kp
07.57.Pt
33.20.Ea
Opis:
This work presents a terahertz system designed for the reflection spectroscopy of different materials located at a distance up to 5 m. The source of the radiation is a tunable solid-state optical parametric oscillator, which generates a narrow-band nanosecond pulses in the range of 0.7-2.5 THz. The signal is detected with relatively fast and having big sensitivity hot electron bolometer. The detailed description of each device and the functioning of the experimental setup are provided as well as the methodology of the measurement is explained. Investigations were performed in the 0.7-2.2 THz range in free space with relative humidity of about 40%. The experiment was divided into three series, each of which was carried out with different distance between the examined sample and the system - 1 m, 3 m, and 5 m. Obtained spectra of selected materials, including explosives, are similar to the results received from a purged time domain spectroscopy system. The observed small deviations are connected with fluctuations of the laser wavelength and the instability of the bolometer.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 689-692
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission Spectra of Materials in the Terahertz Range Measured by a Hot Electron Bolometer-Based System
Autorzy:
Pałka, N.
Walczakowski, M.
Zagrajek, P.
Czerwiński, A.
Sypek, M.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399395.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Ty
78.20.Ci
78.40.-q
78.47.jg
Opis:
This paper presents an optical system for transmission spectral measurements in the terahertz range. The source of radiation is a tunable solid-state laser, which generates a narrow-band nanosecond pulses in the range 0.67-2.68 THz and based on optical parametric oscillator phenomenon. The signal is detected with a fast and sensitive hot electron bolometer. Principle of generation and detection of pulses as well as methodology of measuring spectral characteristics are presented. We compared the results obtained with the free-space setup, which is based on the optical parametric oscillator and hot electron bolometer, with a purged time domain spectroscopy system in the range of 0.7-2.2 THz.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 538-541
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensors and systems for the detection of explosive devices - an overview
Autorzy:
Bielecki, Z.
Janucki, J.
Kawalec, A.
Mikołajczyk, J.
Pałka, N.
Pasternak, M.
Pustelny, T.
Stacewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/221624.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
explosive device sensors
detection of explosive materials
Opis:
The paper presents analyses of current research projects connected with explosive material sensors. Sensors are described assigned to X and γ radiation, optical radiation sensors, as well as detectors applied in gas chromatography, electrochemical and chemical sensors. Furthermore, neutron techniques and magnetic resonance devices were analyzed. Special attention was drawn to optoelectronic sensors of explosive devices.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 3-28
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł

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