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Tytuł:
X-Ray Absorption Spectroscopy
Autorzy:
Mobilio, S.
Powiązania:
https://bibliotekanauki.pl/articles/1931690.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.85.+n
78.70.Dm
Opis:
X-ray absorption spectroscopy, today widely used as a tool for structural investigations, is described. Theoretically it is shown that above an absorption edge the absorption coefficient is well approximated by a sum of terms, each one describing a particular path followed by the photoelectron outgoing from the atom. Such geometrical feature allows to use X-ray absorption spectroscopy for structural investigations. The data analysis procedures are outlined. Applications of the single scattering region, generally known as EXAFS to semiconductors alloys, to metallic clusters and to the crystallization of amorphous metallic glasses are illustrated. Multiple scattering calculations and their relation to experimental spectra is discussed in the case of Mn ions in solution. Application of the multiple scattering to determine the three-body correlation function in a-Si:H is shown.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 645-661
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cavity Enhanced Absorption Spectroscopy Sensor
Autorzy:
Nowakowski, M.
Wojtas, J.
Bielecki, Z.
Mikołajczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807740.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.50.Qx
42.79.Sz
43.60.-c
07.07.Df
Opis:
The paper presents opportunities of cavity enhanced absorption spectroscopy technique application in nitrogen oxides (NO_{x}) detection. In this method the concentration of an absorbing gas is determined by measure of decay time of the light pulse trapped in an optical cavity. The measurements are not sensitive to fluctuation of both laser power and photodetector sensitivity. The cavity enhanced absorption spectroscopy technique is a modification of cavity ring down spectroscopy technique where the off-axis adjustment of the resonator is used. NO_{x} detection is carried out in the visible and infrared range. The signal is registered with a developed low noise photoreceiver. Features of the presented sensor show that it is possible to build a portable trace gases sensor. Its sensitivity could be comparable with chemical detectors. Such a system has several advantages: relatively low price, small size and weight, and detection possibility of other gases.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 363-367
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Delayed differential detection for absorption spectroscopy recovery
Autorzy:
Cong, Menglong
Sun, Dandan
Powiązania:
https://bibliotekanauki.pl/articles/173211.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wavelength modulation spectroscopy
WMS
absorption
derivative spectrum
harmonic detection
laser diode
Opis:
An elaborately designed system has been devoted to the recovery of the line shape function of absorption spectrum. Laser power passing through trace gas has been divided into the real-time and delayed components, and their difference, i.e. the equivalent of the first-order derivative spectrum, is recorded and integrated to reconstruct the absorption line profile. Since the real-time and delayed signals are derived from the only gas cell and photodetector, the elimination of background is more effective, relative to the general used double beam detection that involves two gas cells and photodetectors. Compared with the 1st harmonic detection used in the wavelength modulation spectroscopy, here the generation of derivative spectrum is achieved without modulating the injection current of laser. Additionally, the expensive lock-in amplifier working for wavelength modulation spectroscopy is replaced by a homemade device, which is made of an all-pass filter and an instrumentation amplifier. Therefore, the complexity and cost are significantly reduced, and the stability is improved. For the purpose of validation, recovering of the absorption spectroscopy is carried out using a methane sample at its R(3) absorption line of the 2ν3 overtone, and the obtained data are found to be in a high agreement with theoretical deductions.
Źródło:
Optica Applicata; 2019, 49, 2; 303-315
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface X-Ray Absorption Spectroscopy: Basic Concepts and Applications
Autorzy:
Lagarde, P.
Powiązania:
https://bibliotekanauki.pl/articles/1963303.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.Gy
78.70.Dm
Opis:
The application to surface problems of X-ray spectroscopy has started almost at the same time as in materials science. While the theoretical basis is obviously the same, SEXAFS has some experimental peculiarities which are reviewed here. Some examples will then be given.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 641-647
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Channel Optoelectronic Sensor Employing Cavity Enhanced Absorption Spectroscopy
Autorzy:
Wojtas, J.
Powiązania:
https://bibliotekanauki.pl/articles/1493278.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
42.25.Dd
42.55.Px
42.60.Da
42.62.Fi
Opis:
In the paper, a description of two-channel of optoelectronic sensor basing on cavity enhanced absorption spectroscopy is presented. In contrast to the typical cavity enhanced absorption spectroscopy systems, here a special optical system is applied. It provides possibility to direct more than one beam of laser radiation into a cavity. Thus, special lasers controller system and photoreceiver were developed as well. The setup includes two pulsed laser diodes. The optical signals from the lasers are registered with one special constructed photoreceiver, which is characterized by wide range of the detected wavelengths. Moreover, there was applied time division multiplexing technique, well-known in the telecommunication systems. Every laser is assigned to the suitable channel - the strictly determined temporary window. In this window, the signal from the exits of the optical cavity is registered. In the system, optical signal from many laser sources can be measured and value of absorption coefficient at a few different wavelengths can be determined parallel. Typical cavity enhanced absorption spectroscopy system is designed to measure only one gas concentration, while the developed setup provides possibility to detect a trace concentration of two gases at the same time.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 763-766
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calorimetric Absorption Spectroscopy of Deep Defects and Quantum Dots
Autorzy:
Heitz, R.
Podlowski, L.
Böhrer, J.
Hoffmann, A.
Broser, I.
Bimberg, D.
Powiązania:
https://bibliotekanauki.pl/articles/1933692.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
73.20.Dx
71.70.Gm
Opis:
In recent years calorimetric absorption spectroscopy has been developed to a powerful tool of semiconductor spectroscopy based on the detection of nonradiative relaxation processes. Calorimetric absorption spectroscopy is an ultrasensitive quantitative absorption technique. Recent investigations of Fe in III-V semiconductors and of InAs/GaAs quantum dots are presented here to illustrate the potential of the method. Sharp absorption lines are observed at the low energy onset of the Fe $\text{}^{3+}\text{}^{/}\text{}^{2+}$ charge transfer band in III-V semiconductors. Calorimetric absorption spectroscopy measurements in the mK range reveal a strong temperature dependence of their absorption strength identifying unambiguously Fe$\text{}^{3+}$($\text{}^{6}$A$\text{}_{1}$(S)) as a ground state. The excited state is attributed to (Fe$\text{}^{2+}$,h). The importance of exchange interaction for the observed fine structure is pointed out and binding energies are determined. The quantum yield of the intracenter $\text{}^{5}$Τ$\text{}_{2}$-$\text{}^{5}$E transition of F$\text{}^{2+}$ is determined to be below 50% at 2 K. A correlation between the nonradiative relaxation rate and the isotope splitting of the $\text{}^{5}$Τ$\text{}_{2}$-$\text{}^{5}$E transition is observed, demonstrating the crucial role of the dynamical Jahn-Teller coupling of the $\text{}^{5}$Τ$\text{}_{2}$ state to local Τ$\text{}_{2}$ modes for the multiphonon relaxation process. Quantum dots having a d-function density of states should exhibit no Stokes shift between absorption and emission as observed for one- and two-dimensional systems. Calorimetric absorption spectroscopy demonstrates ground state absorption coinciding in energy with the luminescence for self- organized InAs/GaAs quantum dot structures grown by MBE. Transitions into excited hole states are resolved and a comparison to photoluminescence excitation spectroscopy is presented.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 619-630
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femtosecond X-ray Absorption Spectroscopy οf a Light-Driven Spin-Crossover Process
Autorzy:
Milne, C.
Pham, V.
Gawelda, W.
Nahhas, A.
van der Veen, R.
Johnson, S.
Beaud, P.
Ingold, G.
Borca, C.
Grolimund, D.
Abela, R.
Chergui, M.
Bressler, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/1539083.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
75.30.Wx
Opis:
Understanding the initial steps during ultrafast molecular reactions involving large spin state changes is a vital goal in structural dynamics research. These involve knowledge of the geometric structure of the system. Ultrafast X-ray absorption spectroscopy with 50-100 picosecond time resolution establishes the geometric structure of the short-lived (τ = 0.6 ns) high spin state. Here we focus on time-resolved X-ray absorption studies with 160-200 fs temporal resolution to monitor the structural evolution in this spin-conversion process.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 391-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitive detection of acetylene by second derivative spectra with tunable diode laser absorption spectroscopy
Autorzy:
Deng, H.
Sun, J.
Li, P.
Liu, Y.
Yu, B.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/174963.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tunable diode laser absorption spectroscopy
TDLAS
signal processing
Savitzky–Golay filter
trace gas detection
Opis:
A tunable diode laser absorption spectrometer was developed for trace acetylene gas analysis, the system performance was evaluated by combing an appropriate digital signal processing methods, i.e., Savitzky–Golay smoothing and differentiation algorithm. The calculation of the derivative spectra by this method is accompanied by simultaneous data smoothing. Based on the 2nd deriv- ative spectra detection method, the Allan variance technique indicates a C2H2 detection limit of 1.7ppm for 1-s averaging time, and a minimum noise level of 62ppb (parts per billion), at the optimum integration time of ~60s. The calculated 2nd derivative spectra with better resolution, lower detection limits, save signal processing time, and improve the ability to distinguish unresolved spectral signals.
Źródło:
Optica Applicata; 2016, 46, 3; 353-363
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Absorption Spectroscopy as a Probe of the Structure of Polyaminocarboxylate-Eu(III) Complexes in Solution
Autorzy:
Mondry, A.
Riehl, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/1929802.pdf
Data publikacji:
1993-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Wc
78.55.Hx
Opis:
Absorption spectroscopy was used to study the aqueous solution structure of Eu(III) complexes with DTPA (diethylenetriaminepentaacetic acid) and TTHA (triethylenetetraaminehexaacetic acid). Analysis of the oscillator strengths of the 4f ↔ 4f transitions and of the Judd-Ofelt intensity parameters, τ$\text{}_{λ}$, was performed in order to investigate the formation and the type of bonding in Eu(III)-DTPA and Eu(III)-TTHA species occurring in solution. The correlation of these results with those from other methods made it possible to suggest a relatively complete model of Eu(III)-polyaminocarboxylate coordination.
Źródło:
Acta Physica Polonica A; 1993, 84, 5; 969-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of atomic absorption spectroscopy to food sciences (A study on Persea americana Mill – Avocado)
Autorzy:
Verma, Vishwa N.
Powiązania:
https://bibliotekanauki.pl/articles/1182920.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
avocado
persea americana mill
aas
elemental analysis
element-concentration
Opis:
Our health is very much dependent to our balance meals. The body needs different kinds of minerals for its different functions. Keeping this idea in mind the spectroscopic study on Persea Americana Mill (Avocado Fruit) has been taken into account. The investigation shows that the avocado (Persea Americana Mill) is an ideal food for the balance of minerals in our body. The quantitative investigation using atomic absorption spectroscopic technique shows the presence of Ca, Cd, Co, Cu, Fe, Mg, Mn, Pb and Zn elements in seed (nut), leaf and flesh of avocado. The concentration of Ca and Mg were found very high in nut, leaf and flesh; out of which the concentration of Mg (100809 mg/Kg) was highest in leaf followed by flesh and nut.
Źródło:
World Scientific News; 2016, 49, 2; 104-116
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of the two-dimensional gas temperature distribution based on tunable diode laser absorption spectroscopy
Autorzy:
Shao, J
Wang, L
Ying, C
Powiązania:
https://bibliotekanauki.pl/articles/174322.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tomographic
modified adaptive algebraic reconstruction technique (MAART)
tunable diode laser absorption spectroscopy (TDLAS)
Opis:
Based on tunable diode laser absorption spectroscopy and modified adaptive algebraic reconstruction technique, two-dimensional tomographic reconstruction was derived for the gas temperature distribution in the range of 600–1400 K in the controlled projections. It is explicitly shown that the quality of temperature reconstruction is heavily dependent on the relative sensitivity of the selected spectrum and the algorithm of modified adaptive algebraic reconstruction technique but independent of the complexity of the present field distribution. When the relative sensitivity is less than 1.5, the accuracy of reconstruction relates to the relative sensitivity of the selected spectrum and improves with the increase in relative sensitivity. When the relative sensitivity is larger than 1.5, the accuracy is mainly limited by the algorithm of modified adaptive algebraic reconstruction technique.
Źródło:
Optica Applicata; 2015, 45, 2; 183-198
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid Phase Extraction for Evaluation of Occupational Exposure to Pb (II) Using XAD-4 Sorbent Prior to Atomic Absorption Spectroscopy
Autorzy:
Shahtaheri, S. J.
Khadem, M.
Golbabaei, F.
Rahimi-Froushan, A.
Ganjali, M. R.
Norouzi, P.
Powiązania:
https://bibliotekanauki.pl/articles/90822.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
lead
sample preparation
atomic absorption spectroscopy
Opis:
Lead is an important constituent widely used in different industrial processes. For evaluation of workers’ exposure to trace toxic metal of Pb (II), solid-phase extraction (SPE) was optimized. SPE using mini columns filled with XAD-4 resin was developed with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, the amount of resins, and sample matrix interferences. Lead ions were retained on a solid sorbent and then eluted, followed by a simple determination of analytes with flame atomic absorption spectrometery. The obtained recoveries of metal ions were greater than 92%. This method was validated with 3 different pools of spiked urine samples; it showed a good reproducibility over 6 consecutive days as well as 6 within-day experiments. This optimized method can be considered successful in simplifying sample preparation for a trace residue analysis of lead in different matrices when evaluating occupational and environmental exposures is required.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 2; 137-145
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Condense-Phase BBCEAS Measurements at UV Wavelength
Autorzy:
Nouna, Noora Sh. Oraha Qas
Powiązania:
https://bibliotekanauki.pl/articles/1190113.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Broadband cavity enhanced absorption spectroscopy
BBCEAS
Liquids
Absorption spectroscopy
Ultraviolet light emitted diode
UV-LED
Opis:
Broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to make measurements on liquid phase species using a UV LED and an optical cavity formed by R ≥ 0.99 ultra violet mirror set. The detector is an Andor CCD spectrograph. Measurements is made on a number of dyes dissolved in water and placed in a 1 cm quartz cuvette at zero degrees angle of incidence between the cavity mirrors. The most sensitive measurements are made with the R ≥ 0.99 mirror set on congo red at 397 nm which produced an αmin(t) value of 2.1 × 10-6 cm-1 Hz-1/2 and a LOD of 0.19 nM.
Źródło:
World Scientific News; 2016, 35; 17-29
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduction of optical noise in near-infrared range laser hygrometry
Autorzy:
Stacewicz, Tadeusz
Winkowski, Mateusz
Kuk, Natalia
Powiązania:
https://bibliotekanauki.pl/articles/2204345.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hygrometer
laser
absorption spectroscopy
optical interference
Opis:
A contactless laser hygrometer based on light absorption by H2O molecules at 1392.5 nm is described. However, measurement results can be affected by optical noise when applied to an atmospheric tunnel or glass cuvette. The noises (occurring in the form of periodic fringes in the recorded spectrum) come from unexpected interference of the light beams reflected from surfaces of the windows or other optical elements. The method of their suppression is described in this article. It is based on wavelength modulation and signal averaging over the fringes period. Also, an experiment confirming the usefulness of this method is described here.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 169--181
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of rubber powder mass flow rate on process of plasma pyrolysis
Autorzy:
Szuszkiewicz, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/297804.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
plasma pyrolysis
rubber waste
thermal utilization
absorption spectroscopy
Opis:
The paper describes an experimental examination of the thermal utilization of used rubber. The research was carried out to examine the influence of rubber powder mass flow rate on the plasma pyrolysis of rubber. An arc plasma generator was applied. Ar and a mixture of Ar and H2 were used as plasma gases. The composition of gaseous products was analyzed by infrared absorption spectroscopy. All of the rubber introduced to the plasma jet was decomposed. The outgoing gas did not contain any toxic chemical compounds such as NOx or HCN.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2019, 22(4); 305-318
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 59

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