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Wyszukujesz frazę "Karczewski, M." wg kryterium: Autor


Tytuł:
Unusual Time Dependence of Magnetization Relaxation in MBE Grown Epilayer of CdMnTe
Autorzy:
Witowski, A. M.
Moll, H. P.
Wyder, P.
Karczewski, G.
Wojtowicz, T.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1934049.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.60.Wm
76.30.Fc
Opis:
The temporal behavior of the magnetization due to the spin-lattice relaxation for bulk and MBE grown epilayer of CdMnTe is compared. The time dependence of the epilayer magnetization changes (dM/dt) is nonmonotonic. After the main part, a second structure appears. It can be explained only by the assumption of energy storage and a delayed additional rise of specimen temperature. The nature of the storage is unknown.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 953-956
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Resolved Photoluminescence Study of the Wide (Cd,Mn)Te/(Cd,Mg)Te Quantum Well
Autorzy:
Kutrowska, J.
Bugajny, P.
Baranowski, M.
Bryja, L.
Syperek, M.
Wójs, A.
Misiewicz, J.
Wiater, M.
Karczewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1399154.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.47.D-
78.67.De
Opis:
The static and dynamic properties of excitons and trions in a 80 nm wide $Cd_{1-x}Mn_xTe/Cd_{0.7}Mg_{0.3}$Te quantum well with extremely small Mn content (x=0.00027) have been studied by means of time-integrated and time-resolved photoluminescence experiment at low and elevated temperatures. The trion binding energy has been estimated to be 2.6 ± 0.8 meV. The exciton and trion lifetimes have been measured to be ≈ 150 ps, and ≈ 200 ps, respectively. The temperature dependence of both lifetimes together with the multicomponent character of the PL decay process suggest a spatial localization of excitons and trions in the investigated quantum well.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 895-897
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Dynamic Dielectric Function "Anomaly" for HgSe:Ga and HgSe:Fe
Autorzy:
Szuszkiewicz, W.
Karczewski, G.
Jeżewski, M.
Witkowska, B.
Mycielski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1887004.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.20.Ci
78.30.Fs
Opis:
Reflectivity spectra of HgSe crystals highly doped with Ga and Fe, respectively, were investigated in the spectral region close to the absorption edge at temperatures between 12 K and 295 K. From the analysis of the structure observed in reflectivity the temperature dependence of the Fermi energy was determined for both kinds of crystals.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 369-372
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing methodology of small unmanned platform on the chassis dyno
Autorzy:
Karczewski, M.
Polak, F.
Powiązania:
https://bibliotekanauki.pl/articles/243717.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
road transport
simulation
dyno chassis
examination of unmanned vehicle
Opis:
The article shows construction solution of chassis dyno, designed for small-unmanned platform hybrid drive testing. Brief fore design of chassis dyno were also presented. Most important parts of dyno are module design of dyno. Each of dyno module consists of one free roll and one roll powered by electrical engine for inertia braking. Asynchronous electric engines for dyno stand were selected. Maximum torque, with respect to vehicle wheel torque has to be greater than Mo < 50 Nm, maximum linear speed of vehicle can’t be greater than Vp ≤ 40 km/h, minimal vehicle dimensions: axle base greater than 500 mm, wheel base greater than 770 mm, inverters allow to connect in series enable synchronous operation by computer, during tests, received energy is dispersed in resistors, emergency shut off of each engines. Methodology of measurements, based on UDC test, was presented. Dyno stand was used for hybrid propulsion testing of small-unmanned vehicle. Dyno was used for hybrid drive testing, where measurement of electrical parameters, proportional to load of vehicle drive system, were collected and other parameters such as battery temperature, and electric engines or fuel consumption during tests. Tests were performed during various load and speed of vehicle. The developed methodology of research should allow for a comprehensive study of this type of vehicle in terms of overall efficiency, reliability and energy needs.
Źródło:
Journal of KONES; 2016, 23, 4; 201-207
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Study of Photoluminescence from Deep CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Quantum Wells
Autorzy:
Kutrowski, M.
Wojtowicz, T.
Karczewski, G.
Kopalko, K.
Zakrzewski, A. K.
Janik, E.
Grasza, K.
Łusakowska, E.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1876361.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
78.55.Et
Opis:
The photoluminescence studies in CdTe/CdMnTe quantum wells are reported in the temperature range 10-300 K. The MnTe concentration in the barriers is x = 0.3, 0.5, 0.63 and 0.68. Thus the potential wells in our samples are very deep, of the order of ≈ 800 meV in the conduction band and ≈ 200 meV in the valence band in the case of the x = 0.68 sample. In spite of the large lattice mismatch (related to high x value) between the wells and the barriers the observed line widths are as narrow as 2 meV in the case of 100 Å. Clear manifestations of internal strain are observed. In particular, the temperature coefficient of the luminescence energies shows strong dependence on the width of wells.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 500-504
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Confined Explosions of Composite Explosives and Layered Charges
Autorzy:
Maiz, L.
Trzciński, W. A.
Szala, M.
Paszula, J.
Karczewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/358488.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
thermobaric
composite explosives
layered charges
confined explosion
QSP
Opis:
In the present work, the confined explosions of cylindrical homogeneous and layered charges composed of two different types of macroscopic granular multi-component RDX-based composites were investigated. These composites were obtained by the so-called “wet slurry method”. For comparison, charges consisting of simple mixtures instead of the composites, TNT and phlegmatized RDX (RDXph) were also studied. The effect of the following parameters: the structure of the macroscopic granular composite, the type of charge (cylindrical pressed material or layered with an RDXph core), oxygen availability (air or argon atmosphere) and the aluminium particle size, on the quasi-static pressure (QSP) measured inside a 150 dm3 explosion chamber was determined. Solid post-detonation residues from inside the explosion chamber were also collected and analyzed. A combination of all of these results enabled very important conclusions about aluminium combustion and behaviour during the explosion of composite and layered charges, to be drawn.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 4; 957-977
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Related Spectroscopy of CdTe-Based Quantum Dots
Autorzy:
Gaj, J.
Kazimierczuk, T.
Goryca, M.
Koperski, M.
Golnik, A.
Kossacki, P.
Nawrocki, M.
Wojnar, P.
Karczewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1585136.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.70.Gm
75.75.+a
78.55.Et
Opis:
This work contains a selection of our recent experimental results in the field of the spin-related spectroscopy of individual CdTe-based quantum dots. After a short description of the sample growth and experimental methods, optical measurements of the charge state dynamics are presented. Then the influence of in-plane anisotropy of the excitonic states of a quantum dot is discussed, followed by a description of experimental studies of information read-out and writing on quantum dot spin states. In particular, spin memory of a single $Mn^{++}$ ion embedded in a CdTe quantum dot is quantitatively assessed. In an outlook part, perspectives opened by recently developed ZnTe lattice-matched Bragg reflectors are discussed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 795-799
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Relaxation Processes in Quantum Well Structures of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/Cd$\text{}_{1-x}$Mg$\text{}_{x}$Te
Autorzy:
Khachapuridze, A.
Ivanov, V. Yu.
Godlewski, M.
Karczewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/2035595.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Ji
72.25.Rb
76.70.Hb
78.55.Et
Opis:
Fast spin relaxation of Mn$\text{}^{2+}$ ions in a magnetic quantum well of CdMnTe with 1% Mn fraction is related to a very efficient spin-flip interaction between Mn ions and free carriers. This mechanism of spin relaxation becomes dominant at increased excitation densities. The observed response of the photoluminescence bands to the Mn$\text{}^{2+}$ magnetic resonance indicates that free carriers are heated at the magnetic resonance conditions. A decrease in formation/recombination rates of free and trion excitons is observed. Donor bound exciton photoluminescence is enhanced, which we relate to delocalization of free excitons, caused by interaction with microwave heated free carriers.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 643-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Dependent Interactions of Free Carriers and Manganese Ions in Nanostructures of Wide Band Gap II-Mn-VI Semiconductors - Mechanism of Lifetime Reduction
Autorzy:
Yatsunenko, S.
Khachapuridze, A.
Ivanov, V. Yu.
Godlewski, M.
Khoi, Le Van
Gołacki, Z.
Karczewski, G.
Goldys, E. M.
Phillips, M.
Klar, P. J.
Heimbrodt, W.
Powiązania:
https://bibliotekanauki.pl/articles/2036034.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
76.30.Fc
76.70.Hb
78.55.Et
Opis:
Based on the results of optically detected magnetic resonance and time-resolved investigations we relate the observed lifetime shortening of intra-shell Mn$\text{}^{2+}$ emission to spin dependent magnetic interactions between localized spins of Mn$\text{}^{2+}$ ions and spins/magnetic moments of free carriers. We show that this mechanism is active in both bulk and in low dimensional structures, such as quantum wells, quantum dots, and nanostructures.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 643-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopy of Indirect Excitons in Vertically Stacked CdTe Quantum Dot Structures
Autorzy:
Kukliński, K.
Kłopotowski, Ł.
Fronc, K.
Wojnar, P.
Wojciechowski, T.
Czapkiewicz, M.
Kossut, J.
Karczewski, G.
Wojtowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1492851.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
78.67.Hc
32.60.+i
Opis:
We show that by means of an electric field we can tune the energy levels in vertical quantum dot pairs and study transitions related to recombination of direct and indirect excitons. With decreasing the reverse bias, we observe both the blue- and red-shifted indirect exciton transitions. Based on the band profile of our device, we conclude that the former corresponds to the recombination of the electron and hole localized in the top and the bottom dot, respectively and the latter is related to the recombination of the electron and hole localized in the bottom and the top dot, respectively.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 856-858
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Correlations of Donor Charges in MBE CdTe
Autorzy:
Suski, T.
Wiśniewski, P.
Litwin-Staszewska, E.
Wasik, D.
Przybytek, J.
Baj, M.
Karczewski, G.
Wojtowicz, T.
Zakrzewski, A.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1934021.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
71.55.Gs
Opis:
We present experimental evidence that at high pressures indium donors in CdTe localize electrons in spatially correlated manner. We have studied Hall mobility, μ$\text{}_{H}$, as a function of electron concentration, n$\text{}_{H}$, at T=77 K. Changes of n$\text{}_{H}$ have been achieved by two methods. High pressure freeze-out of electrons onto localized states of In-donors leads to the mobility enhancement with respect to the situation when n$\text{}_{H}$ has been modified by means of a subsequent annealing of the sample. As a result, depending on the degree of spatial correlations in the impurity charges arrangement, different values of μ$\text{}_{H}$ correspond to the same value of n$\text{}_{H}$. The variation of mobility with electron concentration suggests that the localized state of In-donor represents likely negatively charged DX state.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 929-932
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single-Photon Emission from a Highly Excited CdTe Quantum Dot
Autorzy:
Nowak, S.
Goryca, M.
Kazimierczuk, T.
Gaj, J.
Golnik, A.
Kossacki, P.
Wojnar, P.
Karczewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1811969.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.55.Et
78.67.-n
78.47.-p
Opis:
Time-resolved correlation measurements were performed to examine the statistics of photon emission from a single quantum dot at high excitation levels. The range of strong powers was determined by the saturation of intensity of excitonic lines. The significant contribution of pulsed background luminescence forced us to sophisticated analysis of the photoluminescence spectra. For quantum dots grown in the Stranski-Krastanov mode, one-photon emission was found to a good approximation. Fluctuation type quantum dots exhibit a significant level of multiphoton emission.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1273-1278
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected Principles of Feeding Systems Design: Simulation vs Industrial Experience
Autorzy:
Perzyk, M.
Kochański, A.
Mazurek, P.
Karczewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/379595.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
castings defects
simulation software
feeding flow
krzepnięcie
wady odlewów
przepływ
oprogramowanie
Opis:
Simulation software dedicated for design of casting processes is usually tested and calibrated by comparisons of shrinkage defects distribution predicted by the modelling with that observed in real castings produced in a given foundry. However, a large amount of expertise obtained from different foundries, including especially made experiments, is available from literature, in the form of recommendations for design of the rigging systems. This kind of information can be also used for assessment of the simulation predictions. In the present work two parameters used in the design of feeding systems are considered: feeding ranges in horizontal and vertical plates as well as efficiency (yield) of feeders of various shapes. The simulation tests were conducted using especially designed steel and aluminium castings with risers and a commercial FDM based software. It was found that the simulations cannot predict appearance of shrinkage porosity in horizontal and vertical plates of even cross-sections which would mean, that the feeding ranges are practically unlimited. The yield of all types of feeders obtained from the simulations appeared to be much higher than that reported in the literature. It can be concluded that the feeding flow modelling included in the tested software does not reflect phenomena responsible for the feeding processes in real castings properly. Further tests, with different types of software and more fundamental studies on the feeding process modelling would be desirable.
Źródło:
Archives of Foundry Engineering; 2014, 14, 4; 77-82
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Search for Dimensionality Crossover of Spin-Glass Freezing in Superlattices of Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te/CdTe
Autorzy:
Sawicki, M.
Dietl, T.
Karczewski, G.
Wojtowicz, T.
Kossut, J.
Skośkiewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1952078.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Rr
75.50.Lk
Opis:
SQUID measurements of the time decay of the thermoremanent magnetization (field-cooled in 1000 Oe) at long time scale, 10$\text{}^{2}$ < t < 10$\text{}^{5}$ s, are presented for MBE grown Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te. We found that for both thin (32 Å) and thick (2500 Å) layers the spin-glass dynamics is characterized by a similar value of k = -(1/T$\text{}_{f}$)(dT$\text{}_{f}$/dlogt) > 0.05, indicating the absence of the phase transition at nonzero temperature under the experimental conditions.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 919-922
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Search for Dimensional Effects in Spin-Glass Transition in Thin Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Multilayers
Autorzy:
Sawicki, M.
Dietl, T.
Skośkiewicz, T.
Karczewski, G.
Wojtowicz, T.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1943818.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Rr
75.50.Lk
75.30.Kz
75.50.-y
Opis:
SQUID magnetic measurements of CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te, x ≃ 0.5, multi-layers with different CdMnTe layer thickness w reveal the persistence of the spin-glass irreversibilities down to ≃ 16 Å thin layers, i.e., well beyond the previously postulated 40 Å as a quasi-2D threshold. The freezing temperature T$\text{}_{f}$ is found to be a monotonic function of w, and it obeys a scaling law T$\text{}_{f}$ ∝ w$\text{}^{a}$, with a 0.8 similar to that for canonical spin-glasses. Magnetic properties of all studied structures are found to be independent of the orientation of the magnetic field.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 1038-1042
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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