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Wyszukujesz frazę "enhancement factor" wg kryterium: Wszystkie pola


Tytuł:
Elastic Enhancement Factor: Mesoscopic Systems versus Macroscopic 2D Electromagnetic Analogue Devices
Autorzy:
Sokolov, V.
Zhirov, O.
Powiązania:
https://bibliotekanauki.pl/articles/1400563.pdf
Data publikacji:
2015-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Gg
24.60.Lz
05.45.Mt
Opis:
Excess of probabilities of the elastic processes over the inelastic ones is a common feature of the resonance phenomena described in the framework of the random matrix theory. This effect is quantitatively characterized by the elastic enhancement factor $F^{(β)}$ that is the typical ratio of elastic and inelastic cross-sections. Being measured experimentally, this quantity can supply us with information on specific features of the dynamics of the intermediate complicated open system. We discuss properties of the enhancement factor in a wide scope from mesoscopic systems to macroscopic analogue electromagnetic resonators and demonstrate essential qualitative distinction between the elastic enhancement factor's peculiarities in these two cases. Complete analytical solution is found for the case of systems without time-reversal symmetry and only a few open equivalent scattering channels.
Źródło:
Acta Physica Polonica A; 2015, 128, 6; 990-993
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and Experimental Studies of the Elastic Enhancement Factor for 2D Open Systems
Autorzy:
Ławniczak, M.
Białous, M.
Yunko, V.
Bauch, S.
Sirko, L.
Powiązania:
https://bibliotekanauki.pl/articles/1400561.pdf
Data publikacji:
2015-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
03.65.Nk
Opis:
We present the results of numerical and experimental studies of the elastic enhancement factor W for microwave rough and rectangular cavities simulating two-dimensional chaotic and partially chaotic quantum billiards in the presence of moderate absorption. We show that for the frequency range ν=15.0-18.5 GHz, in which the coupling between antennas and the system is strong enough, the values of W for the microwave rough cavity lie below the predictions of random matrix theory and on average above the theoretical results of V. Sokolov and O. Zhirov, Phys. Rev. E 91, 052917 (2015). We also show that for the partially chaotic rectangular billiard the enhancement factor W calculated by applying the Potter-Rosenzweig model with κ=2.8±0.5 is close to the experimental one.
Źródło:
Acta Physica Polonica A; 2015, 128, 6; 974-978
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of linewidth enhancement factor (LEF) on routes to chaos in optically injected semiconductor lasers
Autorzy:
Al-Hosiny, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/2033881.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
injection locking
chaos
linewidth enhancement factor
routes to chaos
Opis:
The effect of the linewidth enhancement factor (LEF) or α-factor on two common routes to chaos (mainly period-doubling and quasi-periodic routes) in optically injected semiconductor laser is theoretically investigated using bifurcation diagrams. The value of the LEF is slightly modified to examine the sensitivity of routes to chaos to any variation in the LEF. Despite the fact that LEF enhances chaos in the system, both routes are found to be highly insensitive to the variation in the LEF.
Źródło:
Optica Applicata; 2021, 51, 4; 621-632
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the dose enhancement factor of high intensity low mono-energetic X-ray radiation with labeled tissues by gold nanoparticles
Autorzy:
Ranjbar, H.
Shamsaei, M.
Ghasemi, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/148638.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiation therapy
energy optimization
dose enhancement factor
dose absorption
gold nanoparticles
MCNPX code
Opis:
The aim of radiotherapy is to maximize the dose applied to the tumor while keeping the dose to the surrounding healthy tissue as low as possible. To further enhance dose to a tumor, techniques to radiosensitization of the tumor, using high atomic number elements, have been proposed. The aim of this study was to investigate the influence of using gold nanoparticles as a contrast agent on tumor dose enhancement when the tissue is irradiated by a typical mono energy X-ray beam. To improve the conventional radiotherapy enhancement of the absorbed dose in a tumor tissue and to spare the skin and normal tissues during irradiation in the presence of concentration agent, a model based on a Monte Carlo N-Particle eXtended (MCNPX) computer code has been designed to simulate the depth dose in a phantom containing an assumed tumor. Test was carried out in two phases. In phase 1, verification of this model using the MCNPX was evaluated by comparing the obtained results with those of the published reports. In phase 2, gold was introduced into assumed tumor inside the phantom at different depths in the simulation program. Simulation was performed for four different concentrations of gold nanoparticles using a low mono-energetic parallel beam of synchrotron radiation. The obtained results show that the optimum energy for dose enhancement is found to be around 83–90 keV for all gold concentrations. The dose enhancement factor is increased linearly with concentration and diminished in depth along the central beam in the tumor. This approach of introducing contrast agents in conventional radiotherapy could hopefully prepare new treatment planning and improve the efficiency of tumor therapy.
Źródło:
Nukleonika; 2010, 55, 3; 307-312
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical study of the heat transfer and pressure drop in triangular chevron channels
Autorzy:
Dolatabadi, H.
Aghdam, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/949298.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
heat transfer
pressure drop
thermal enhancement factor
phase shift
Opis:
Experimental and Numerical studies were carried out on turbulent heat transfer and friction factor loss through a triangular chevron channel. For uniform wall heat flux equal 1350 (W/m²) using air as a working fluid. Reynolds number varied from 3000 to 10000, phase shifted at the range of 0≤ϕ≤180, with variation distance between chevron surfaces (5 ≤ D ≤ 35 mm). Nu increased and TEF decreased in increasing of Re. The TEF and Nu increased with closing to channel phase shift angle 90˚, the best performance was noticed on phase shift, ϕ=90º. At the end of this paper effect of distance between chevron surfaces presented, The TEF and Nu increased with decreasing to channel distance and the best performance was noticed on closing to D=5(mm).
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 751-763
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania szybkości absorpcji CO2 w wodnych roztworach węglanów potasowych z dodatkiem 2-etyloaminoetanolu
Investigations of the rate of CO2 absorption into aqueous potash solutions with 2-ethylaminoethanol
Autorzy:
Moniuk, Wł.
Pohorecki, R.
Nosewicz, M.
Szczepańska, M.
Powiązania:
https://bibliotekanauki.pl/articles/2071147.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
ditlenek węgla
2-etyloaminoetanol
proces Benfield
absorpcja z reakcją chemiczną
współczynnik przyspieszania wnikania masy
carbon dioxide
2-ethylaminoethanol
BENFIELD process
absorption with chemical reaction
enhancement factor
Opis:
W pracy przedstawiono wpływ stężenia cząstek na częstość obrotów mieszadła niezbędną dla wytworzenia drobnoziarnistej zawiesiny całkowitej. Pompujące ku dołowi pojedyncze mieszadło z sześcioma pochylonymi łopatkami o stosunku średnicy zbiornika do średnicy mieszadła Did = 3 użyto do mieszania zawiesiny kredy. Pomiary przeprowadzono w zbiorniku cylindrycznym (średnica 200 i 300 mm) z przegrodami. Średnia średnica objętościowa cząstek wynosiła 4,6 μm, a ich stężenie zmieniano w granicach od 2,5 do40%obj.
The effect of particle concentration on impeller speed necessary for fine suspension mixing is presented in the paper. A single down pumping pitched six-blade impeller with the vessel to impeller diameter ratio Did = 3 was used for mixing of chalk suspension. Measurements were carried out in cylindrical baffled vessels with diameters of 200 and 300 mm. The mean volumetric diameter of particles was 4.6 μm and the mean volumetric concentration changed in the range from 2.5% to 40%.
Źródło:
Inżynieria i Aparatura Chemiczna; 2010, 3; 75-76
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of protrusions on the initiation of partial discharges in XLPE high voltage cables
Autorzy:
AlShaikh Saleh, Mohammad
Refaat, Shady S.
Olesz, Marek
Abu-Rub, Haitham
Guziński, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/2090691.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FEA
finite elements analysis
protrusions
XLPE
water trees
partial discharge
void
space charge
stress enhancement factor
analiza elementów skończonych
kable XLPE
polietylen kablowy
polietylen sieciowany
wyładowanie niezupełne
ładunek przestrzenny
Opis:
This paper is focusing on 3D Finite Elements Analysis (FEA) based modelling of protrusions as defects or imperfections in the XLPE high voltage cable. This study is aiming to examine the impact protrusions have on the initiation of partial discharges. Spherical and ellipsoidal protrusions with different sizes at the conductor screen of the high voltage cable is an essential content of this paper. In addition, a spherical gas-filled void is placed inside and outside the protrusions, and a water tree produced from protrusions is under consideration. The partial discharge influence taking place at the protrusions and the stress enhancement factor is determined for all the variations mentioned to quantify the rise in the inception of partial discharges due to the protrusions.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; e136037, 1--9
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of protrusions on the initiation of partial discharges in XLPE high voltage cables
Autorzy:
AlShaikh Saleh, Mohammad
Refaat, Shady S.
Olesz, Marek
Abu-Rub, Haitham
Guziński, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/2173562.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FEA
finite elements analysis
protrusions
XLPE
water trees
partial discharge
void
space charge
stress enhancement factor
analiza elementów skończonych
kable XLPE
polietylen kablowy
polietylen sieciowany
wyładowanie niezupełne
ładunek przestrzenny
Opis:
This paper is focusing on 3D Finite Elements Analysis (FEA) based modelling of protrusions as defects or imperfections in the XLPE high voltage cable. This study is aiming to examine the impact protrusions have on the initiation of partial discharges. Spherical and ellipsoidal protrusions with different sizes at the conductor screen of the high voltage cable is an essential content of this paper. In addition, a spherical gas-filled void is placed inside and outside the protrusions, and a water tree produced from protrusions is under consideration. The partial discharge influence taking place at the protrusions and the stress enhancement factor is determined for all the variations mentioned to quantify the rise in the inception of partial discharges due to the protrusions.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; art. no. e136037
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of speech communication technology performance using Adaptive-Control Factor based Spectral Subtraction method
Autorzy:
Alim, I. A.
Kolawole, M. O.
Powiązania:
https://bibliotekanauki.pl/articles/309098.pdf
Data publikacji:
2013
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
Adaptive-Control Factor
MBSS
musical noise
subbands
Opis:
This paper presents speech enhancement technique based on Spectral Subtraction (SS) method. SS is a renowned noise reduction technique that works on the principle that noise spectrum estimate over the entire speech spectrum can be subtracted from the noisy signal. On the contrary, most of the noise encountered in the real-world conditions is majorly colored. Unlike Additive White Gaussian Noise (AWGN), colored noise does not affect the speech signal uniformly over the entire spectrum. To mitigate effects of colored noise on the processed signal, we propose a Multi-Band Spectral Subtraction (MBSS) method using novel Adaptive-Control Factor (ACF). The spectrum is divided into frequency sub bands based on a nonlinear multi-band frame and various signal-to-noise ratios (SNRs) are considered. The proposed scheme results in better system performance with quality signal and unlike the basic SS method. It mitigates the effects of anomaly known as “musical” tones artifacts in the processed signal that result in residual noise and speech distortion. The computational complexity involved is minimal. Furthermore, simulation results show that the proposed algorithm removes more colored noise without removing the relatively low amplitude speech signal over the entire speech spectrum. Subjective listening tests, with clean speech signals and different noise levels, show discernable performance of our proposed method when compared with the conventional SS approach.
Źródło:
Journal of Telecommunications and Information Technology; 2013, 2; 35-39
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power quality enhancement of three-phase front-end rectifier of UPS system using current injection technique
Autorzy:
Dhomane, G. A.
Suryawanshi, H.
Powiązania:
https://bibliotekanauki.pl/articles/262756.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
high frequency current injection
high power factor
soft transition
power factor correction circuit
Opis:
Power Quality, in terms of power factor and harmonics, is greatly hampered by a three-phase rectifier used as a front-end ac-to-dc converter in many systems including a UPS. This paper presents the high power factor operation of the converter with reduced total harmonic distortion up to 4%. The power quality up gradation is due to high-frequency current injection, at the input of the front-end rectifier. A small filter is required at the output for filtering the high-frequency content. Sinusoidal PWM technique is used for controlling the output voltage. DSP is used for generating the desired gate pulses. The converter has high efficiency, low EMI emissions, high power packing density and suitable for UPS system. A Simulation and experimentation is carried out on a 3 kW converter and experimental results are in good agreement with simulation results.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2008, 14, 2; 35-39
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł

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