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Wyszukujesz frazę "Stępniewski, J." wg kryterium: Autor


Tytuł:
Coupling of LO Phonons to Excitons in GaN
Autorzy:
Wysmołek, A.
Łomiak, P.
Baranowski, J. M.
Pakuła, K.
Stępniewski, R.
Korona, K. P.
Grzegory, I.
Boćkowski, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1952430.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
63.20.Mt
71.55.Eq
Opis:
The photoluminescence of homoepitaxial and heteroepitaxial GaN layers is reported. It is shown that the coupling between LO phonons and neutral acceptor bound excitons is much stronger than the coupling between LO phonons and neutral donor bound excitons. In undoped homoepitaxial layer, in spite of that the no-phonon emission due to donor bound excitons is one order of magnitude stronger than the acceptor bound excitons emission, the predominant structure in the LO phonon replica of the excitonic spectrum is related to optical transitions involving acceptor bound excitons. Temperature studies showed that at higher temperature the LO phonon replica is related to free excitons.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 981-984
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-Luminescence Study of Silicon-Vacancy in 6HSi
Autorzy:
Wysmołek, A.
Wardak, K.
Stępniewski, R.
Baranowski, J.
Potemski, M.
Tymicki, E.
Grasza, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047066.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
71.55.-i
71.55.Ht
Opis:
The magneto-spectroscopy studies of luminescence related to silicon-vacancy, in high quality 6H-SiC crystals grown by the seeded physical vapor transport method, are presented. The superior optical quality of these crystals allowed us to resolve a doublet structure of the 1.398 eV emission line (V$\text{}_{2}$ line), commonly assigned to the transitions involving two singlet states of the silicon-vacancy. Experiments performed in magnetic fields up to 20 T showed that each doublet constituent of the V$\text{}_{2}$ line splits into four components for the magnetic field parallel to the c-axis of the 6H-SiC crystals. This result could be hardly explained in terms of a singlet to singlet transition. The analysis of the angle-resolved luminescence experiments in high magnetic fields serves us to discuss the symmetry of the defect states responsible for the V$\text{}_{2}$-line in silicon carbide.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 437-442
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aeration properties and enzyme activity on the example of Arenic Chernozem [Tisice]
Autorzy:
Wlodarczyk, T.
Glinski, J.
Stepniewski, W.
Stepniewska, Z.
Brzezinska, M.
Kuraz, V.
Powiązania:
https://bibliotekanauki.pl/articles/24679.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
aeration property
soil
catalase
enzyme activity
oxidoreductase
black earth
dehydrogenase activity
soil enzyme
Źródło:
International Agrophysics; 2001, 15, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single GaN/AlGaN Quantum Dot Spectroscopy
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047382.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The detailed analysis of the emission from these structures enables the observation of pairs of lines separated by the energy up to 3 meV. They behave in a different way under different excitation power that suggests that this doublet structure can be associated with the exciton and trion (or biexciton recombination). It is observed that for different quantum dots the energy of the charged exciton complex emission could be higher or lower than the neutral exciton one. It is discussed in terms of a competition between attractive e-h and repulsive e-e (h-h) Coulomb interaction that occurs because of the existence of the built-in electric field that separates electrons and holes in the dot.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 233-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal Evolution of Multi-Carrier Complexes in Single GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2044542.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The narrow lines in the microphotoluminescence spectra due to the single quantum dots are observed. Both energy and intensity of these lines show temporal fluctuations. Statistical analysis based on the correlation matrix allowed us to identify objects, which are affected by photo-induced electric field fluctuations. Relations between emission lines participating in the spectrum are discussed.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 879-884
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Evolution of the Microluminescence Energy οf GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791354.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Time evolution of the microphotoluminescence from low-density GaN/$Al_{x}Ga_{1-x}N$ quantum dots grown by metal organic chemical vapor deposition using in situ etching of AlGaN is presented. The observed effect is related to the energy changes that begin immediately after sample illumination with the exciting laser light and saturate after some time. Typically, the luminescence energy decreases and the change is exponential with characteristic times in a range between several dozen and several hundred seconds. However, sometimes we observed the energy increase with characteristic times in a range between several and a few hundred seconds. The obtained results are discussed in terms of the metastable change of the electric field, induced by spontaneous polarization present in GaN/AlGaN structure (in the growth direction), and strain- or defect-induced changes of the electric field in the vicinity of the dot.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 933-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exciton in 2D Cubic Inclusion in Hexagonal GaN
Autorzy:
Suffczyński, M.
Stępniewski, R.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1968430.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
78.66.-w
61.72.Nn
Opis:
An inclusion of cubic GaN in an otherwise hexagonal matrix is considered to be equivalent to an effective quantum well. The exciton binding energy in a quantum well of a finite potential barrier height in the conduction and valence bands is calculated in the effective mass approximation with a variational envelope function type of Bastard and Takagahara. The exciton binding energy and the energy of exciton recombination line are computed, as a function of the well width, for realistic potential barrier heights and band-offset ratios.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 993-996
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of Photon Polarization in GaAs/AlAs Single Quantum Dot Emission
Autorzy:
Suffczyński, J.
Trajnerowicz, A.
Kazimierczuk, T.
Piętka, B.
Kowalik, K.
Kossacki, P.
Golnik, A.
Nawrocki, M.
Gaj, J. A.
Wysmołek, A.
Stępniewski, R.
Potemski, M.
Thierry-Mieg, V.
Powiązania:
https://bibliotekanauki.pl/articles/2047725.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.66.Fd
78.67.Hc
78.47.+p
Opis:
We study polarization resolved correlation between photons emitted in cascaded biexciton-exciton recombination from a single quantum dot formed in type II GaAs/AlAs bilayer. Magnetic field induced transition from anisotropy controlled to the Zeeman controlled emission was demonstrated by a circular polarization correlation between the emitted photons. A simple model describing the effect allowed us to determine the anisotropic exchange splitting of the excitonic state. This method of the anisotropic exchange splitting determination can be useful in the case when other methods are not sensitive enough.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 461-466
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dehydrogenase activity of some Hungarian soils as related to their water and aeration status
Autorzy:
Stepniewski, W.
Stepniewska, Z.
Glinski, J.
Brzezinska, M.
Wlodarczyk, T.
Przywara, G.
Varallyay, G.
Rajkai, K.
Powiązania:
https://bibliotekanauki.pl/articles/26443.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
iron
reduced iron
soil aeration
soil
water
Hungary
dehydrogenase activity
aeration status
Źródło:
International Agrophysics; 2000, 14, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxygen concentration in primary roots of broadbean, lupin and pea seedling as measured with a microelectrode
Autorzy:
Stepniewski, W.
Zausig, J.
Przywara, G.
Horn, R.
Powiązania:
https://bibliotekanauki.pl/articles/25979.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
Lupinus angustifolius
Helianthus annuus
pea
root
seed
Vicia faba
electrode construction
concentration
seedling
measurement procedure
lupin
broad bean
soil moisture
Pisum sativum
oxygen
Źródło:
International Agrophysics; 1998, 12, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudometeorite from Łapino (Pomerania, North Poland)
Autorzy:
Stępniewski, M.
Borucki, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059303.pdf
Data publikacji:
2001
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Łapino
morth Poland
iron silicide
pseudometeorite
Opis:
A boulder, found in a gravel pit by Łapino near Gdańsk in 1954, was noted as unusual. Among various erratics ice-derived from Scandinavia in the Quaternary, this one had an extraordinary appearance; unusually dark, heavy and strongly magnetic. An extraterrestrial origin was suggested. The border resembles an intrusive breccia with numerous periclase-bearing fragments in a magnetite-clinopyroxene-olivine matrix. A single grain with a metallic luster, a few centimetres in diameter, was identified as the iron silicide (Fe3Si). Only two natural occurrences of iron silicide have been described, both from meteorites. However, the isotopic analysis showed an absence of radiogenic nuclides (10Be, 26Al, 36Cl), and the ratio of oxygen isotopes (delta 17O and delta 18O) suggested a terrestrial origin. Thus the stone is probable artifact, presumably the product of an unidentified foundry.
Źródło:
Geological Quarterly; 2001, 45, 3; 343-348
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Związki między opadem deszczu a spływem powierzchniowym i spłukiwaniem gleby na poletkach doświadczalnych o różnym użytkowaniu (Guciów – Roztocze Środkowe)
Relationship between rainfall and runoff and slope wash on plots of varying land use (Guciow – Central Roztocze Region)
Autorzy:
Stepniewski, K.
Demczuk, P.
Rodzik, J.
Siwek, K.
Powiązania:
https://bibliotekanauki.pl/articles/2084665.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:
wies Guciow
Roztocze Srodkowe [geogr.]
opady atmosferyczne
splyw powierzchniowy
gleby
poletka doswiadczalne
erozja
ocena
Opis:
The work contains results of observations on the relationship between precipitation and surface runoff and slopewash on the surface plots in UMCS Science Station in Guciów. Observations come from a period of 6 years (2000-2006). Tests were conducted on three plots with typical use of the area. Two plots, with meadow and fallow land, were on the south slope and inclination of 3-5°. The third plot was established in the forest, whose slope was inclined at an angle of 13-18° and east display. Cover of soil in the station area, are eroded podsol soil, with silty sand in the arable layer. Obtained results of the observations were included in the form of regression equations describing the relationship between rainfall during the summer and surface runoff, runoff and slopewash of soil's, rainfall erosivity factor and slopewash.
Źródło:
Prace i Studia Geograficzne; 2010, 45; 229-241
0208-4589
Pojawia się w:
Prace i Studia Geograficzne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dwa lęgi pary kruka Corvus corax w jednym sezonie
Two broods of the Raven Corvus corax in one season
Autorzy:
Stepniewski, J.
Luczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/79739.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Zoologiczne
Tematy:
ptaki
krukowate
kruk
Corvidae
Corvus corax
ptaki legowe
legi ptakow
okres legowy
Źródło:
Ornis Polonica; 2015, 56, 4
2081-9706
Pojawia się w:
Ornis Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of pedaling techniques with platform pedals
Autorzy:
Stępniewski, A. A.
Grudziński, J.
Powiązania:
https://bibliotekanauki.pl/articles/955232.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
rower
pedałowanie
wał korbowy
cycling
platform pedal
pedaling
cycling efficiency
Opis:
The paper analyzes a pedaling technique with platform pedals in which the influence of the geometric and tribological parameters on the torque course of the active forces in the crank rotation axis is determined. Distribution of forces of feet acting on pedals as a function of the crank rotation angle was performed and on this basis the specific pedaling zones and their ranges and the courses of the value of variable active torque and pedaling work during the full cycle were determined. The course of changes in the movements in the ankle joint is described with a function depending on the crank and limb position and loading of the joint. A numerical example has also been presented and a discussion of the results has been carried out.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 3; 633-642
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of additional foil wraps on the tightness of the packaging of bales
Autorzy:
Stępniewski, A. A.
Nowak, J.
Powiązania:
https://bibliotekanauki.pl/articles/972941.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
baled silage
cylindrical bale
stretch film
tightness
mathematical model
simulation model
Opis:
The work analyzed the effect of additional wraps on the number of layers and thus the tightness of the material under protection. It was assumed that all the overlaps of each two consecutive wraps are the same, and each additional wrap causes the same increase of all the tabs. The mechanical properties of the film and its dimensions were taken into account. We have written our own simulation program that allows us to calculate the percentage of a given number of film layers on the side of the bale and the visualization of the distribution of layers in its cross-section. Calculation examples have been provided. Conclusions and suggestions resulting from the obtained simulation results have been formulated.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2018, 7, 1; 145-150
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł

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