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    Tytuł:
    Validity of MRI brain perfusion imaging method
    Autorzy:
    Karczewski, B.
    Rumiński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/333584.pdf
    Data publikacji:
    2006
    Wydawca:
    Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
    Tematy:
    obrazowanie medyczne
    obrazowanie rezonansu magnetycznego
    perfuzja mózgu
    medical imaging
    MRI
    brain perfusion
    Opis:
    Brain perfusion imaging using Dynamic Susceptibility Contrast Magnetic Resonance Imaging is very promising method since it can be easily implemented as a standard contrast-based MRI procedure. Quantitative brain perfusion description by DSC-MRI data post processing requires validation. Different validation analysis was performed to verify the influence of a bolus dispersion, delay, low SNR and calculation procedures on final perfusion parameter values. The results indicate that quantitative description of brain perfusion using DSC-MRI is possible and can be acceptable with accuracy about 10%.
    Źródło:
    Journal of Medical Informatics & Technologies; 2006, 10; 55-61
    1642-6037
    Pojawia się w:
    Journal of Medical Informatics & Technologies
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Parametric imaging in dynamic glucose metabolism studies in brain
    Autorzy:
    Rumiński, J.
    Karczewski, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/333769.pdf
    Data publikacji:
    2005
    Wydawca:
    Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
    Tematy:
    obrazowanie parametryczne
    obrazowanie dynamiczne
    przetwarzanie obrazów
    PET
    parametric imaging
    dynamic imaging
    image processing
    Opis:
    Parametric imaging is more and more popular in dynamic brain studies. It enables to quantitatively or semi-quantitatively estimate physiological state and processes in brain. This work analyse the dynamic 18FDG-PET studies for estimation of brain glucose metabolism. The influence of the signal noise is analysed to estimate its influence on the final glucose metabolism parameter values. The LCMRGlc parameter is under investigation. It is based on three compartmental model proposed by Phelps. Using different 18FDG-PET data series obtained from independent sources the Gaussian noise was introduced (with different variance). Then the quality of the model fitting results were estimated. The final results clearly indicates than the noise is highly compensated in microparameter used in calculation of LCMRGlc. Concluding, it is possible to estimate the LCMRGlc parameter value even in the presence of noise.
    Źródło:
    Journal of Medical Informatics & Technologies; 2005, 9; 201-208
    1642-6037
    Pojawia się w:
    Journal of Medical Informatics & Technologies
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Z badań nad występowaniem komarów (Diptera, Culicinae) i ich zwalczaniem z apomocą aerozoli
    Contribution to the occurrence of Diptera, Culicinae and their control using the aerosols
    Issledovanija pojavlenija komarov (Diptera, Culicinae) i borby s nimi pri pomoshhi aehrozolejj
    Autorzy:
    Wegorek, W.
    Karczewski, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/838578.pdf
    Data publikacji:
    1967
    Wydawca:
    Polskie Towarzystwo Parazytologiczne
    Opis:
    In order to determine the optimal terms of control of antropophilic species, the ecological-faunistical investigations were carried out taking into considerations the phenology of these mosquitos. Basing upon the results the control measures were elaborated and the evaluation of efficiency of aerosol application was done. In pilot investigations, only in the summer months, the presence of 14 antropophilic species was stated, among them 12 species out of the genus Aedes Meig. The dominant was A. vexans Meig., the subdominant was A. sticticus Meig. In sampling with the light source self-trapping, for general faunistical investigation were registered 16 species with ornitophilic species Culex pipiens pipiens L. at the top and with the for a longest time occurring Anopheles (Anopheles) maculipennis Meig. and Theobaldia annulata Schrank. In the water reservoirs were present exclusively the larvae of the genus Aedes. The species composition of this area was very rich in comparison to the number of 22 species for the Warszawa-region, noted by different investigators. During the full-season investigations of the 1965, in the spring-summer time, while sampling using baits and the self-trapping devide dominated species from the genus Aedes in the autumn using the self-trapping devide the C. pipiens dominated mixed up with T. annulata. A. maculipennis as well as not numerously present species of the genus Aedes (A. cinereus, A. vexans and other). In the water reservoirs dominated that year the species of the genus Theobaldia N-L., Anopheles, to a lower degree Culex. The rise of intensity of occurrence of Diptera, Culicinae during the season was noted four time, twice at very high degree. The control of the pests was based upon the method of laying down a chemical barrier. A technique of aerosol application in the open area was developed using the hand pulsating apparatus of the type "Swingfog" (GFR). A preparation rontaining 10% of DDT was applied in aerosol. The measures were applied as dry fog. The efficiency, at the rate of application of 8 l of chemical per ha was equal to 100% (in control of larvae in water reservoirs), at the rate of 6 1/ha (against the imago stages) it was 99.3-100%, and at 2-2.2 1/ha – 99.2-99.5%. These control measures resulted in lowering the intensity of presence of those pests in the investigated area. High operativeness of the chosen technique is indicated by the labor efficiency up to 5 ha/hour with the working width equal to 5-30 meters on lower costs as compared to the commonly applied dassical measures of control.
    Źródło:
    Annals of Parasitology; 1967, 13, 4-5
    0043-5163
    Pojawia się w:
    Annals of Parasitology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Z badań nad występowaniem komarów (Diptera, Culicinae) i ich zwalczaniem za pomocą aerozoli
    Contribution to the occurrence of Diptera, Culicinae and their control using the aerosols
    Issledovanija pojavlenija komarov (Diptera, Culicinae) i borby s nimi pri pomoshhi aehrozolejj
    Autorzy:
    Węgorek, W.
    Karczewski, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/2177760.pdf
    Data publikacji:
    1967
    Wydawca:
    Polskie Towarzystwo Parazytologiczne
    Opis:
    In order to determine the optimal terms of control of antropophilic species, the ecological-faunistical investigations were carried out taking into considerations the phenology of these mosquitos. Basing upon the results the control measures were elaborated and the evaluation of efficiency of aerosol application was done. In pilot investigations, only in the summer months, the presence of 14 antropophilic species was stated, among them 12 species out of the genus Aedes Meig. The dominant was A. vexans Meig., the subdominant was A. sticticus Meig. In sampling with the light source self-trapping, for general faunistical investigation were registered 16 species with ornitophilic species Culex pipiens pipiens L. at the top and with the for a longest time occurring Anopheles (Anopheles) maculipennis Meig. and Theobaldia annulata Schrank. In the water reservoirs were present exclusively the larvae of the genus Aedes. The species composition of this area was very rich in comparison to the number of 22 species for the Warszawa-region, noted by different investigators. During the full-season investigations of the 1965, in the spring-summer time, while sampling using baits and the self-trapping devide dominated species from the genus Aedes in the autumn using the self-trapping devide the C. pipiens dominated mixed up with T. annulata. A. maculipennis as well as not numerously present species of the genus Aedes (A. cinereus, A. vexans and other). In the water reservoirs dominated that year the species of the genus Theobaldia N-L., Anopheles, to a lower degree Culex. The rise of intensity of occurrence of Diptera, Culicinae during the season was noted four time, twice at very high degree. The control of the pests was based upon the method of laying down a chemical barrier. A technique of aerosol application in the open area was developed using the hand pulsating apparatus of the type "Swingfog" (GFR). A preparation rontaining 10% of DDT was applied in aerosol. The measures were applied as dry fog. The efficiency, at the rate of application of 8 l of chemical per ha was equal to 100% (in control of larvae in water reservoirs), at the rate of 6 1/ha (against the imago stages) it was 99.3-100%, and at 2-2.2 1/ha – 99.2-99.5%. These control measures resulted in lowering the intensity of presence of those pests in the investigated area. High operativeness of the chosen technique is indicated by the labor efficiency up to 5 ha/hour with the working width equal to 5-30 meters on lower costs as compared to the commonly applied dassical measures of control.
    Źródło:
    Wiadomości Parazytologiczne; 1967, 13, 4-5; 455-457
    0043-5163
    Pojawia się w:
    Wiadomości Parazytologiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The HRCT image analysis for quantitative description of peripheral airways remodelling
    Autorzy:
    Rumiński, J.
    Karczewski, B.
    Mincewicz, G.
    Aloszko, A.
    Krzykowski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/333680.pdf
    Data publikacji:
    2004
    Wydawca:
    Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
    Tematy:
    obrazy HRCT
    przebudowa dróg oddechowych
    analiza obrazu
    HRCT images
    airways remodelling
    image analysis
    Opis:
    Airways remodelling is currently described as a process occurring before asthma becomes clinically manifest, which is confirmed by biopsy studies. The aim of this study was to test and validate image analysis methods to describe the changes such as peripheral airways remodelling in HRCT readings. Different methods of airways extraction from HRCT images were investigated including: manual identification of an airway region major axes on original and scaled images (using different interpolation techniques like pixel resize, bilinear interpolation and cubic convolution), manual extraction of the density profile through the major axes of an airway region, semi-automatic method using active contours and the Hough transform. Methods were tested with original images and artificially modified images by blurring and noise addition (Gaussian, Laplacian and salt-and-pepper). Results suggest that popular image magnification using cubic convolution is not suitable for accurate estimation of shape properties of small regions. Smart pixel resizing enables to delineate a region of inner and outer borders with subpixel accuracy reducing the total error of the wall thickness estimation. Additionally smoothing must be reduced to the minimum in the case of an active contour application.
    Źródło:
    Journal of Medical Informatics & Technologies; 2004, 7; MIP21-30
    1642-6037
    Pojawia się w:
    Journal of Medical Informatics & Technologies
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wytrzymałość pętli wplatanych na linach podwójnie plecionych
    The strength of splices in the double-braided ropes
    Autorzy:
    Zajączkowska, B.
    Karczewski, A.
    Czaja, A.
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/344314.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydawnictwo Uniwersytetu Morskiego w Gdyni
    Tematy:
    osprzęt żaglowy
    takielunek
    lina pleciona
    pętla wplatana
    splot Dyneema
    sails
    rigging
    braided rope
    splice
    Dyneema
    Opis:
    Cechą wyróżniającą statki żaglowe z grona innych obiektów pływających są żagle. To cecha widoczna, za którą kryją się mniej romantyczne elementy, takie jak maszty, liny i osprzęt. Rozpostarcie białych płócien na maszcie i następnie żeglowanie wymaga sprawnego operowania nimi, co wiąże się z doborem odpowiedniego ich zestawu, ułożenia i napięcia. To maszty są kręgosłupem takielunku, a liny jego mięśniami i ścięgnami. Do poprawnego działania całego układu przyczynia się każda z jego części. Tak jak w żywym organizmie mięśnie muszą być przyłączone do kośćca właściwym przyczepem, tak na jachcie liny należy odpowiednio połączyć z pozostałymi komponentami takielunku. W artykule skupiono się na problemie łączenia lin z innymi elementami osprzętu żaglowego i wytrzymałości tego połączenia. Przeanalizowano rozwiązanie mające zarówno cechy techniki tradycyjnej, łączenia za pomocą pętli wplatanych, jak i elementy współczesnego jachtingu, ponieważ jako materiał zastosowano linę DynaLite. Badania zostały wykonane w ramach pracy inżynierskiej na Wydziale Oceanotechniki i Okrętownictwa Politechniki Gdańskiej. W zakresie zadania znajdowało się badanie wytrzymałości pętli o różnych długościach wplotu oraz określenie wpływu parametrów konstrukcji splotu na jego wytrzymałość. Porównano również właściwości przyjętego rozwiązania z połączeniem za pomocą węzła ratowniczego oraz wytrzymałość liny, na której wykonano testy z danymi podanymi przez producenta.
    The distinguishing feature of sailing ships from the group of other floating objects are the sails. This is a visible feature behind which are less romantic elements such as masts, ropes and rigging. Raising the white sails and then sailing requires efficient handling, which involves choosing the right sails-set, them position and tension. These masts are the backbone of the rigging, and the ropes with its muscles and tendons. Every part of it contributes to the correct functioning of the whole system. As in living organisms, the muscles must be attached to the bone in the proper trailer, so that the ropes on the yacht should be properly connected to the other rigging components. This article presented the problem of joining ropes with other components and the strength of this connection. A solution that has both the characteristics of traditional techniques, by the splice the rope and the elements of new yachting trends has been analyzed, as DynaLite has been used as a material. The research was done at the Faculty of Ocean Engineering and Ship Technology of Gdansk University of Technology. The task was to test the strength of the loop with different lengths of the splice and to determine the impact of the parameters on its strength. The strength of the connection with bowline has been checked. The strength of the tested rope with the data provided by the manufacturer were also compared.
    Źródło:
    Prace Wydziału Nawigacyjnego Akademii Morskiej w Gdyni; 2017, 32; 106-120
    1730-1114
    Pojawia się w:
    Prace Wydziału Nawigacyjnego Akademii Morskiej w Gdyni
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Single Particle and Collective Spin Excitations in Semimagnetic Quantum Wells
    Autorzy:
    Perez, F.
    Jusserand, B.
    Richards, D.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/2038315.pdf
    Data publikacji:
    2004-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.25.Dc
    73.21.-b
    75.70.-i
    78.30.-j
    Opis:
    Collective and single-particle spin-flip excitations of a two-dimensional electron gas in a semimagnetic Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te quantum well are observed by resonant Raman scattering. Application of a magnetic field splits the spin-subbands and a spin-polarization is induced in the electron gas. Above some critical field, a collective spin-flip mode, which disperses with in-plane wave vector, dominates the spectra. The energy of this mode is given by the bare Zeeman energy at vanishing wave vector as predicted by Larmor's theorem and its in-plane dispersion is well described by a model of the interacting polarizability of a spin polarized electron gas when both exchange and correlation are taken into account.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 3; 311-317
    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:
    Jod i wapń w wodach do picia woj. białostockiego
    Iodine and calcium in drinking water in the Białystok province
    Autorzy:
    Januszko, T.
    Karczewski, J.
    Poplawska, T.
    Smorczewska, B.
    Suszczynska-Falecka, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/873239.pdf
    Data publikacji:
    1977
    Wydawca:
    Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
    Tematy:
    woj.bialostockie
    woda pitna
    jod
    wapn
    zawartosc jodu
    zawartosc wapnia
    badania naukowe
    Źródło:
    Roczniki Państwowego Zakładu Higieny; 1977, 28, 5
    0035-7715
    Pojawia się w:
    Roczniki Państwowego Zakładu Higieny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Dynamics in CdTe/CdMnTe Multiquantum Well Structures Grown by Molecular Beam. Epitaxy on GaAs Substrate
    Autorzy:
    Godlewski, M.
    Koziarska, B.
    Suchocki, A.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Bergman, J.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934057.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.60.-p
    78.47.+p
    73.20.Fz
    71.35.+z
    Opis:
    The results of picosecond photoluminescence kinetics of four different CdTe/CdMnTe multiquantum well structures grown by MBE on GaAs substrates are presented. The experimental results show that excitons in CdTe quantum wells are strongly localized by potential fluctuations. Photoluminescence decay times of the localized excitons are considerably shorter (about 120 ps) than those reported for free or quasi-free excitons. An influence of Mn in the barriers on exciton properties is demonstrated. For narrow quantum wells as well as for the multiquantum well structure with the highest Mn mole fraction the excitons migrate during their decay to the states with a lower potential energy. Longer decay times are observed for quasi-localized excitons. We show also that for strongly localized excitons the energy transfer between localized and donor bound excitons is less efficient.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 985-989
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence of Donor-Doped ZnSe Films Grown by Molecular Beam Epitaxy
    Autorzy:
    Karczewski, G.
    Hu, B.
    Yin, A.
    Luo, H.
    Dobrowolska, M.
    Furdyna, J. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1932090.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.55.Ln
    78.55.Et
    Opis:
    We studied the effect of the donor doping of ZnSe films on their photoluminescence properties. The samples were doped during the molecular beam epitaxy growth, either with gallium or with chlorine. As the dopant concentration dose increases, the intensity of the band-edge emission first saturates, and then quenches in favor of the deep-level photoluminescence band. The main effect of donor doping on photoluminescence is a strong increase in intensity of the donor-bound exciton line, referred to as I$\text{}_{2}$. For Ga-doped films deep-band emission is much stronger, and the I$\text{}_{2}$-line is slightly weaker than for Cl-doped films with comparable doping level. The results confirm the superiority of chlorine over gallium as an n-type dopant in ZnSe. We discuss the photoluminescence results and relate them to deep level transient spectroscopy data obtained on the same samples.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 245-248
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Recombination Processes in Doped CdTe/CdMnTe Multiple Quantum Well Structures Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968089.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    An influence of doping level on exciton properties in n-doped multiple quantum well structures of CdTe/CdMnTe is studied for multiple quantum well structures prepared in the way that donor (indium) concentration changes within the length of the sample. We show that the formation scenario for neutral donor bound excitons in low-dimensional structures can be different from that observed in bulk samples. We further show that in the case of such quantum well structures we can selectively excite either photoluminescence emission of localized or donor bound excitons, which is a consequence of surprisingly weak energy transfer link between two types of excitonic transitions.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 757-760
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Resonant Raman Spectra of CdTe/ZnTe Self Assembled Quantum Dots
    Autorzy:
    Romčević, N.
    Romčević, M.
    Kostić, R.
    Stojanović, D.
    Abolmasov, B.
    Karczewski, G.
    Galazka, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1807840.pdf
    Data publikacji:
    2009-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    63.22.-m
    78.30.Fs
    78.55.Et
    Opis:
    In this paper we present Raman scattering and photoluminescence spectra measured on CdTe/ZnTe self assembled quantum dots. The photoluminescence spectrum has shown two main emission peaks, both connected with existing of quantum dots. One presents direct deexcitation to ground state and the other is optical phonon (οmega = 207.3 $cm^{-1}$)-assisted deexcitation. The registered multiphonon emission process depends on temperature. At low temperature phonon spectra shows line at 450 $cm^{-1}$ (TA + 2LO in ZnTe) and 595 $cm^{-1}$ (2LO + TO(Γ) in ZnTe).
    Źródło:
    Acta Physica Polonica A; 2009, 116, 1; 88-90
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of Optical Properties of CdTe/CdMnTe Quantum Wells Grown by Molecular Beam and Atomic Layer Epitaxy
    Autorzy:
    Godlewski, M.
    Kopalko, K.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952470.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.+z
    78.47.+p
    78.55.Et
    Opis:
    Optical properties of a series of CdTe/CdMnTe multi quantum well structures grown with MBE and ALE (CdTe quantum wells only) methods are compared. Based on the results of the photoluminescence experiments we conclude that the ALE growth leads to a different lateral scale of quantum well width fluctuations, which results in different exciton properties in two multi quantum well systems studied. In the wells grown with ALE method excitons are less localized. They can migrate in a quantum well plane between quantum well regions varying in thickness by 1 monolayer.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 1012-1016
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Properties in CdTe/CdMnTe Quantum Well Structures with Strong Localization Effects
    Autorzy:
    Godlewski, M.
    Narkowicz, R.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969075.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.-y
    71.55.Jv
    73.20.Mf
    Opis:
    Strong localization effects present in quantum well structures of CdTe/ CdMnTe noticeably affect exciton dynamics and strength and character of exciton-phonon interaction. We show that the temperature dependences of the PL linewidth, PL peak wavelength and PL decay time strongly deviate from those expected for Wannier-excitons in structures with atomically smooth interfaces.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 317-320
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hot Photoluminescence in CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Holtz, P. O.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968096.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    A step-like emission is observed for CdTe/CdMnTe structures δ-doped with In. The new photoluminescence cannot be explained by neither the Raman process nor by the "ordinary" hot photoluminescence. We propose that magnetic interactions are responsible for the new photoluminescence appearing due to a dramatic increase in a thermalization time of hot excitons.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 765-768
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optically Detected Magnetic Resonance of Excess Electrons in CdTe/(Cd,Mg)Te Quantum Wells
    Autorzy:
    Hu, C. Y.
    Ossau, W.
    Yakovlev, D. R.
    König, B.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969094.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.70.Hb
    71.35.-y
    71.35.Ji
    Opis:
    The spin resonance of excess electrons is observed with the detection either on the neutral or the negatively charged exciton X$\text{}^{-}$ emission in type I CdTe/(Cd,Mg)Te quantum wells with excess electrons of low density. It is found that the electron spin-dependent and electron spin-conserving formation and recombination of X$\text{}^{-}$ make the optical detection of the spin resonance of excess electrons feasible. For the first time, optically detected magnetic resonance is used to study fast optical transition processes in the nanosecond timescale where the microwave-induced magnetic transition rate is much lower than the optical transition rate.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 351-354
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ genotypu i modelowych stresorów na wskaźniki fizjologiczne u tuczników
    Vlijanie genotipa i modelnykh stressorov na fiziologicheskie pokazateli otkormochnykh svinej
    The influence of genotype and model stress factors on physiological indices in fattened pigs
    Autorzy:
    Dziewiecki, C.
    Kolataj, A.
    Piekarzewska, A.
    Karczewski, D.
    Zebrowski, Z.
    Blicharski, T.
    Szymanowska, B.
    Tyrolczyk, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/801984.pdf
    Data publikacji:
    1990
    Wydawca:
    Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
    Tematy:
    genotyp
    stresor modelowy
    wskazniki fizjologiczne
    tuczniki
    syndrom stresowy swin
    landrace
    duroc
    uboj
    wydajnosc rzezna
    Opis:
    Соотвeтствубщие исследования охватывали трехпородные помеси свиней: (польской белой вислоухой х крупной белой польской) х нeмецкой белой вислоухой (группа I) и (польской белой вислоухой х крупной белой польской) х дюрок (группа II). В рамках группы I одна погруппа (10 голов) была подвергнута однонедельному голоданию. Группа II oзватывала сверх того подгруппу подвергнутую чрезмерной скученности в станке. Среди исследуемых физиологических признаков наблюдалась высокосущественная разница (50%) между контрольными подгрупцамн обоих генотипов на уровне мышечного гликогена в пользу группы I. Таких разниц не обнаружено среди исследуемых параметров плазмы. Голодание в обеих группах привело к высокосущественному повышению уровня холестерола в плазме; существенное снижение уровня глюказа наблюдалось только в группе I. Голодание не оказывало существенного влияния на уровень белка ни в одной из исследуемых групп откормочников, равно как и не изменялся уровень общих липидов. В рамках последней группы соединений отдельные фракции представлялись различно: уровень свободных жирных кислот повысился 3-4 раза у обеих групп, тогда как концентрация фракции триглицеридов не изменилась в группе I, повышаясь высокосущественно (на 0,20 мМ/л) в группе I у помесей (польская белая вислоухая х крупная белая польская) x дюрок. Активность альдолазы не изменилась ни в одной группе, тогда как активность фосфофруктокиназы не изменилась в группе I, а в группе II повысилась высокосущественно на 50%. Голодание привело к высокосущественному снижению уровня гликогена как в почени так и в свелетных мышцах в обеих исследуемых генетических группах: в группе I трехкратно, в группе II двухкратно. Не установлено заметного влияния степени скученности в станке на исследуемые физиологические параметры. Полученные результаты указывают на различность физиологической реакции в зависимости от генотипа откормочников.
    The investigations covered the following cross-breeds: (Polish Landrace x Polish Large White) x German Landrace (group I) and (Polish Landrace x Polish Large White) x Duroc (group II). Group I was divided into 2 subgroups, one of which was subjected to a week of fasting. Within group II there was created a third subgroup which was subjected to overcrowding. Among the physiological changes examined there occurred a highly significant difference in the level of muscle glycogen (50%) between the control groups (in favour of the group I). Among the serum parameters examined no such differences were observed. After fasting in both groups there occurred a highly significant increase in the plasma cholesterol. A significant decrease in the level of glucose was observed only in the group I. Fasting did not exert any significant effect on the level of proteins in either group, similarly as it did not change the level of total lipids. However, within this last group of compounds individual fractions reacted differently; the level of WKT increased 3-4 times in both groups while the level of triglicerides did not change in the group I, but in the crossbreds with Duroc it increased highly significantly (by 0.20 mM/1). The activity of aldolase did not change in either group, while the activity of PHI, unchanged in the group I, increased significantly in the group II (by 50%). Fasting led to a highly significant lowering of the level of glycogen in the liver and in the skeletal muscles of both genetic groups: thrice in the group I and twice in the group II. There was observed no distinct influence of overcrowding on the physiological parameters examined. The results obtained indicate a differentiated physiological reaction depending on the genotype of the pigs.
    Źródło:
    Zeszyty Problemowe Postępów Nauk Rolniczych; 1990, 384
    0084-5477
    Pojawia się w:
    Zeszyty Problemowe Postępów Nauk Rolniczych
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonradiative Recombination Processes in (CdTe,CdCrTe)/CdMgTe Quantum Well Structures
    Autorzy:
    Godlewski, M.
    Ivanov, V.
    Zakrzewski, A. J.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968108.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.60.-p
    76.70.Hb
    Opis:
    Photoluminescence transitions in (CdTe,CdCrTe)/CdMgTe structure grown by molecular beam epitaxy are studied. Photoluminescence investigations show a very strong reduction of the photoluminescence intensity from chromium doped quantum wells. We explain this fact by a very efficient nonradiative recombination in the chromium-doped quantum wells. The present results indicate that the Auger-type energy transfer from excitons to chromium ions is responsible for the photoluminescence deactivation. The efficiency of this process is evaluated.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 781-784
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission SecondHarmonic Generation in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te at 1.064 µm
    Autorzy:
    Koziarska, B.
    Kowalczyk, L.
    Suchocki, A.
    Wojtowicz, T.
    Zakrzewski, A. K.
    Karczewski, G.
    Janik, E.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873081.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.Ky
    68.70.+w
    Opis:
    Second harmonic generation, created by nanosecond Nd : YAG laser pulses at 1.064 µm with relatively low intensity in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te bulk crystals and thin layers was measured in transmission geometry. The effect practically occurs in a very thin surface layer of the material and it is used as a relatively straightforward method of layer quality characterization. It is shown that the angular dependence of the second harmonic generation intensity in thin layers of CdTe with good crystallographic (and optical) quality agrees very well with the theory in contrary to the samples with some distortions from the ideal structure which exhibits large distortions from the theory.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 423-426
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Transfer in Multiple Quantum Well Structures of CdTe/CdMnTe Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Surma, M.
    Wilamowski, Z.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Holtz, P. O.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968091.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    The direct evidence for the efficient transfer of excitons from 4 nm and 6 nm to 10 nm wide CdTe quantum wells is presented based on the results of photoluminescence and photoluminescence excitation investigation. Efficient transfer is observed for quantum wells separated by thick (50 nm) CdMnTe barriers containing 10% or 30% Mn fraction. A new mechanism of the transfer is proposed, which involves long range dynamic magnetic interactions between free/bound excitons and Mn ions in the CdMnTe barrier regions of the structure.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 761-764
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microwave-Induced Delocalization of Excitons in Ternary Compounds of II-VI and III-V Semiconductors
    Autorzy:
    Ivanov, V. Yu.
    Godlewski, M.
    Khachapuridze, A.
    Yatsunenko, S.
    Wojtowicz, T.
    Karczewski, G.
    Bergman, J. P.
    Monemar, B.
    Shamirzaev, T.
    Zhuravlev, K.
    Leonardi, K.
    Hommel, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035757.pdf
    Data publikacji:
    2003-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.Ji
    72.25.Rb
    76.70.Hb
    78.55.Et
    Opis:
    In this work we employ technique of optically detected cyclotron resonance for evaluation of the role of localization processes in CdTe/CdMnTe and CdMnTe/CdMgTe quantum well structures. From microwave-induced changes of excitonic emissions we evaluate magnitude of potential fluctuations (Stokes shift), correlate optically detected cyclotron resonance results with the results of time-resolved experiments and discuss nature of recombination processes in the limit of a strong localization.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 6; 559-566
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Elastic Properties of Zinc Blende MnTe
    Autorzy:
    Djemia, P.
    Roussigné, Y.
    Stashkevich, A.
    Szuszkiewicz, W.
    Gonzalez Szwacki, N.
    Dynowska, E.
    Janik, E.
    Kowalski, B. J.
    Karczewski, G.
    Bogusławski, P.
    Jouanne, M.
    Morhange, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2038250.pdf
    Data publikacji:
    2004-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    62.20.Dc
    75.50.Pp
    78.35.+c
    Opis:
    The Brillouin light scattering was used to investigate elastic properties of the zinc blende, MBE-grown MnTe layer that was deposited on a (001) GaAs substrate covered by CdTe buffer layer. The three elastic constants of the zinc blende MnTe, namely c$\text{}_{11}$, c$\text{}_{12}$, and c$\text{}_{44}$, were directly determined for the first time from the frequency of the Rayleigh mode, of the pseudo-surface mode, and of the shear horizontal bulk mode traveling parallel to the layer surface. The value of c$\text{}_{11}$ was checked using the frequency of longitudinal bulk waves propagating at different angles from the normal of the layer plane. This value was also independently determined by results of the folding of acoustic phonons, observed for MnTe/CdTe superlattices by the Raman scattering. Finally, the bulk modulus given by the formula B=(c$\text{}_{11}$+2c$\text{}_{12}$)/3 was determined for zinc blende MnTe by ab initio calculations making use of the density functional theory and atomic pseudopotentials; spin polarization of MnTe was taken into account. A satisfactory agreement between theoretical and experimental values was obtained.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 2; 239-247
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Morphology and Selected Properties of Core/Shell ZnTe-Based Nanowire Structures Containing ZnO
    Autorzy:
    Gas, K.
    Janik, E.
    Zaleszczyk, W.
    Pasternak, I.
    Dynowska, E.
    Fronc, K.
    Kolkovsky, V.
    Kret, S.
    Morhange, J. F.
    Reszka, A.
    Wiater, M.
    Caliebe, W.
    Karczewski, G.
    Kowalski, B. J.
    Szuszkiewicz, W.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047950.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Hk
    68.37.Lp
    68.65.La
    81.07.Vb
    Opis:
    We report on an approach to fabricate ZnTe-based core/shell radial heterostructures containing ZnO, as well as on some of their physical properties. The molecular beam epitaxy grown ZnTe nanowires constituted the core of the investigated structures and the ZnO shells were obtained by thermal oxidation of ZnTe NWs. The influence of the parameters characterizing the oxidation process on selected properties of core/shell NWs were examined. Scanning electron microscopy revealed changes of the NWs morphology for various conditions of the oxidation process. X-ray diffraction, high resolution transmission electron microscopy, and Raman scattering measurements were applied to reveal the presence of ZnTe single crystal core and polycrystalline ZnO-shell of investigated structure.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 612-614
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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