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Wyszukujesz frazę "52.80.-s" wg kryterium: Temat


Tytuł:
Time-Resolved X-Ray Diffraction Studies on Biological Systems
Autorzy:
Rapp, G.
Powiązania:
https://bibliotekanauki.pl/articles/1920834.pdf
Data publikacji:
1992-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
87.80.+s
52.50.Jm
Opis:
Understanding of biological function requires knowledge both on structural and dynamical aspects. The aim of time-resolved X-ray diffraction is to combine structural and kinetic methods by monitoring structural or conformational changes within a single protein or assemblies of proteins during their biological action in real time. This requires (i) a powerful X-ray source, (ii) appropriate detectors capable of dealing with high local and total count rates and (iii) a suitable trigger mechanism. These aspects are briefly discussed with emphasis on light as trigger for initiation of structural or conformational changes. Examples are presented on muscle contraction, lipid phase transitions, the photocycle of bacteriorhodopsin and the application of Laue crystallography on the protein p21.
Źródło:
Acta Physica Polonica A; 1992, 82, 1; 103-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of Cu Atoms Diffusion Coefficients in He and Ne - Optimalisation of a Novel Method
Autorzy:
Kwaśniewski, W.
Dzieciołowski, K.
Adamowicz, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/2035632.pdf
Data publikacji:
2002-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Lt
42.60.Lh
52.80.-s
Opis:
A novel method based on two-pulse excitation of a hollow cathode discharge to determine metal atoms diffusion coefficients in noble gases was tested in Cu-He and Cu-Ne systems. The excitation conditions such as time duration of the discharge current pulses and configurations of the hollow cathode discharge were checked. Measurements carried out over the wide range gas pressures allowed obtaining the Cu atoms time-decay curves from which the diffusion coefficients were calculated. The values for Cu atom diffusion coefficients of 570 and 310 cm$\text{}^{2}$ s$\text{}^{-1}$ mbar in He and Ne, respectively were in a good agreement with earlier reported data achieved by using the absorption spectroscopy method. The diffusion coefficient of Cu in $\text{}^{3}$He, the lighter isotope of helium, was also found to be 670 cm$\text{}^{2}$ s$\text{}^{-1}$ mbar that agreed well with the kinetic theory of gases. To authors believe this value was not reported previously.
Źródło:
Acta Physica Polonica A; 2002, 102, 6; 747-757
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing of Partial Discharges in Generator Coil Bars with the Help of Calibrated Acoustic Emission Method
Autorzy:
Witos, F.
Gacek, Z.
Opilski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1811569.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Le
43.60.Lg
52.80.s
77.22.Jp
84.70.+p
Opis:
Investigation results of acoustic emission signals coming from partial discharges within chosen generator coil bar, in relation to measurement results of apparent charge introduced by partial discharges sources, are presented in the article. Analysis is based on amplitude distributions calculated for acoustic emission signals, ordered at different measuring points for different values of the supply voltage. In order to assign acoustic emission signal to its advance degree a descriptor named by an acronym ADP (defined by authors) is calculated for each amplitude distribution. Descriptor families describing acoustic emission signals measured at particular measuring points (for different supply voltages) are presented in relation to apparent charge introduced by acoustic emission sources. These families concerning acoustic emission signals, measured at different measuring points for identical supply voltage, enable us to locate acoustic emission sources with maximum activity.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-249-A-258
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Acoustic Wave Propagation in a Power Transformer Model
Autorzy:
Wotzka, D.
Boczar, T.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807760.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
43.28.Js
Opis:
Analyses of acoustic wave propagation in a model power transformer are presented in the paper. The acoustic wave is induced by partial discharges that are simulated at predefined coordinates in the core and winding. Propagation of the numerical calculated acoustic wave is analyzed within the transient state. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the largest amplitude occurs at the vicinity of the induction position.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 428-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decay of Electric Charge on Corona Discharge Polyethylene
Autorzy:
Zhang, L.
Xu, Z.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/1807998.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
81.05.Lg
84.30.Jc
Opis:
In this paper, surface potential decay after corona charge deposition has been investigated for low density polyethylene (LDPE) films. We believe that the three ways of electron charge decay on the surface of insulating polyethylene film is reasonable. The factor of neutralizing with opposite charge in air is negligible, and leakage along insulator surface or through the body is much more important for electron charge decay. Both ways are related with surface voltage of the sample. When the voltage is lower than a critical value, surface leakage contributes most. If the voltage is higher than this value, the electron energy on the surface of the sample exceeds the critical value and it is easy to cross the "deep trap". In this situation, the body leakage is more important, and the decay on the surface of sample speeds. That is why there exists decay curve crossing phenomenon.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1197-1200
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Avalanche Statistics
Autorzy:
Ficker, T.
Powiązania:
https://bibliotekanauki.pl/articles/1585038.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
52.80.Dy
52.80.Mg
Opis:
A solution of the long-lasting problem with anomalous population statistics of pre-streamer avalanches has been proposed in the form of a new generalized probability density function.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 1018-1020
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring Picosecond Flashover in Closing Coaxial Spark Gap Switch
Autorzy:
Klüss, J.
Hällström, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807883.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
51.50.+v
52.70.Gw
52.80.-s
Opis:
Flashover voltage and picosecond risetime of breakdown in pressurized $SF_{6}$ gas is studied on a coaxial line. Gas pressure is varied from 1 to 19 bar. The homogeneous field gap has an opening from ca. 0.2 to 0.9 mm, and flashover voltages reach 120 kV. Measurements are performed using a D-dot probe with 16 to 20 GHz real-time oscilloscopes and a 50 GHz sampling oscilloscope. Measured risetimes are down to ca. 50 ps, and the dependence of voltage collapse on gas density and electric field between the electrodes is reported. Integrity of data is analyzed and experimental results are compared with present theory found in literature and previous results measured with alternative real-time systems.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1004-1006
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Acoustic Emission Signals Coming from Partial Discharges Caused by Modeled Sources Immersed in Transformer Oil
Autorzy:
Witos, F.
Gacek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1807759.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Le
52.80.-s
77.22.Jp
84.70.+p
Opis:
Investigation results concerning acoustic emission signals coming from partial discharges generated by modeled sources are presented in the paper. These sources have been made using different bushing ends (without any extra elements and with a thread or a pike) situated directly in the oil, but without screens typical for partial discharge investigations in a bushing. Measurements have been carried out using own measuring acoustic emission system DEMA-COMP and - in a parallel way - computer-aided partial discharges measuring system TE 571 (produced by the firm Haefely Trench). Fundamental and advanced analysis of acoustic emission signals has been made. These signals were recorded in 20 measuring situations which need to multiple installation of acoustic emission sensors. Conclusions resultant from own originate advanced analysis of signals content description of properties revealed by defined acoustic emission descriptors.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 422-427
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchronization Study and Introductory Experiment οf Laser-Triggered Surface Flashover in Voltage Pulse
Autorzy:
Pan, R.
Wang, J.
Sun, Y.
Sun, G.
Yan, P.
Zhang, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807974.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
51.50.+v
Opis:
With the aim of studying the characteristics of laser-triggered surface flashover in voltage pulse, synchronization problem of laser pulse and voltage pulse should be solved. A single/double harmonic, with wavelength λ of 1064/532 nm, Q-switched Nd:YAG laser is used to trigger the surface flashover. The synchronization problem is solved using a self-made digital delay/pulse generator. The delay time and jitter of Marx's trigger input and output, Marx's trigger output and Marx's output, laser input and output are respectively measured. Based on the result of the delay time and the timing sequence of the laser triggering system, the synchronization of laser pulse and voltage pulse is obtained through adjusting the channel delay time of digital delay/pulse generator. In addition, introductory experiment of laser-triggered surface flashover is carried out using the flat electrodes and columned insulators.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1167-1169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Application of the Selected Time-Frequency Descriptors Detection of the Acoustic Emission Signals Generated by Multisource Partial Discharges
Autorzy:
Cichon, A.
Powiązania:
https://bibliotekanauki.pl/articles/1795791.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
43.28.Js
Opis:
The paper presents the comparative analysis results of the acoustic emission signals generated by various forms of partial discharges occurring in multisource systems. Modern methods of the signal digital processing: a short-time Fourier transform and continuous and discrete wavelet transforms were applied for the assessment of the results in the time-frequency domain. The acoustic emission signals generated by partial discharges were registered with a WD AH17 contact transducer by the Physical Acoustics Corporation placed on the external part of the tub.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 290-293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wall Confinement Technique by Magnetic Gradient Inversion. Accelerators Combining Induction Effect and Pulsed Ionization. Applications
Autorzy:
Petit, J.
Geffray, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807971.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.-d
52.30.Cv
52.75.Di
52.55.-s
52.80.Pi
Opis:
We published the first description of a disk-shaped MHD aerodyne, combining pulsed ionization and induction systems. Magnetic pressure tends to push away electric discharge, in region of low magnetic field. In the seventies the efficiency of the wall confinement, due to the inversion of the magnetic pressure gradient was demonstrated. It is time now for ambitious MHD projects. We have planned experimental studies of MHD acceleration, combining pulsed ionization, wall confinement and induction system. We intend to study pulsed ionization systems based on wall micro discharges or microwaves action. We present the different features of the project.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1162-1163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Properties of Chosen Acoustic Emission Descriptors Describing Acoustic Signals Measured by Means of Acoustic Emission Method within Oil Transformers
Autorzy:
Witos, F.
Olszewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1506870.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
77.22.Jp
84.70.+p
Opis:
Authors of the paper present investigation results concerning properties of ADP, ADC and ADNC descriptors which have been obtained during measurements made within three oil transformers and then tested also by other methods (electric and dissolved gas analysis ones). Methodology which makes easier an analysis and identification of acoustic emission signals generated by partial discharges is presented. Results obtained by acoustic emission method have been referred to results coming from other measuring methods.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1267-1271
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Properties Characteristic for Acoustic Emission Signals Recorded On-Line in Power Oil Transformers
Autorzy:
Witos, F.
Olszewska, A.
Szerszeń, G.
Powiązania:
https://bibliotekanauki.pl/articles/1493277.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
77.22.Jp
84.70.+p
43.40.Le
43.60.Lq
Opis:
Investigation results of properties characteristic for acoustic emission signals recorded in two selected power oil transformers are presented. Signals were put to the filtration, whereas components coming from partial discharges have been left. The calculations concerned: phase-time characteristics, averaging phase characteristics, averaging short time Fourier transform spectrograms, amplitude distributions of signals, values of acoustic emission descriptor with acronym ADC. On the ground of calculated basic characteristics and maps of ADC descriptor three areas have been selected on lateral walls of transformer tanks. Acoustic emission signals recorded in these areas were analyzed from the point of view how is influence of propagation path on these properties.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 759-762
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anusual Application of Partial Discharges to Diagnose of High Voltage Power Transformers
Autorzy:
Gacek, Z.
Szadkowski, M.
Malitowski, G.
Witos, F.
Olszewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1493101.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Le
52.80.s
07.50.Hp
Opis:
The article contains information on research carried out in Electric Faculty of Silesian University of Technology, made at test stations and aimed at diagnosis how is actual technical state of high voltage power oil transformers. Opinion on a state of transformers is based on analysis results of partial discharge measurements. Authors use simultaneously: electric, acoustic and dissolved gas analysis method. Applied acoustic method is the original own one. Non-conventional application of electric method is proposed, too. In the frame of chosen methodology the partial discharges are measured and next calculations of quantities describing partial discharges within particular methods are carried out in order to describe phenomena commonly for electric and acoustic method. Information sources about level and kind of partial discharges are measurement results obtained from electric method whereas information on places where partial discharges appear is contained in measurement results coming from acoustic method. Authors present selected application results of such a combined measuring method.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 609-615
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of Acoustic Signals Generated by Operation of On Load Tap Changers
Autorzy:
Cichon, A.
Fracz, P.
Zmarzly, D.
Powiązania:
https://bibliotekanauki.pl/articles/1493036.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
43.28.Js
Opis:
Possibilities of application of the acoustic method for the on load tab changers diagnosis has been presented in the paper. The analysis of measurement results gathered during research works performed under laboratory conditions has been presented in detail. The registered acoustic signals have been analyzed in time and time-frequency domains. The time domain analysis has been performed by presentation of time runs and their envelopes determined by use of the Hilbert transform. Evaluation of the time-frequency components has been performed by use of the short-time Fourier transform, the discrete and the continuous wavelet transforms.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 585-588
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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