Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "JI" wg kryterium: Temat


Tytuł:
Dimensional Dependence of Exchange Interactions at High Magnetic Fields
Autorzy:
Zehnder, U.
Kuhn-Heinrich, B.
Ossau, W.
Waag, A.
Landwehr, G.
Cheng, H. H.
Nicholas, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/1952434.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
71.35.Ji
Opis:
We studied the contribution of the breaking of antiferromagnetically coupled spin clusters to the total magnetization in thin (CdMn)Te layers as a function of the layer thickness by reflectivity spectroscopy in magnetic fields up to 45 T. The experimental results show that the contribution of the breaking of antiferromagnetically coupled spin clusters is reduced by decreasing layer thickness.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 989-992
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Search for Thermal Vacancies Forming Close Frenkel Pairs in Fe-Cr Alloys
Autorzy:
Chojcan, J.
Powiązania:
https://bibliotekanauki.pl/articles/2028967.pdf
Data publikacji:
2001-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
76.80.+y
Opis:
The room temperature Mössbauer spectra of $\text{}^{57}$Fe were measured for the bcc Fe$\text{}_{0.948}$Cr$\text{}_{0.052}$ solid solution quenched into water being at about 295 K from different temperatures not exceeding 1000 K, i.e. from the temperatures for which probabilities of formation of "clear" (Schottky) vacancies as well as vacancies forming the separate interstitial-vacancy (Frenkel) pairs are negligibly low. The obtained data were analysed in terms of concentration of unoccupied places in the 14-site surroundings of an $\text{}^{57}$Fe Mössbauer probe in the sample. It turned out that the concentration of vacancies detected by the probe increases with temperature very rapidly - at the rate of about 10$\text{}^{-4}$ K$\text{}^{-1}$. The result may suggest that the Mössbauer probe is sensitive to a possible thermal distortion of the lattice or creation of very close Frenkel pairs (the interstitial is the nearest neighbour of the vacant lattice site).
Źródło:
Acta Physica Polonica A; 2001, 100, 5; 723-729
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of Boron-Carbide as Radiation Shielding
Autorzy:
Kara, Ü.
Tekin, H.
Calik, A.
Akkurt, İ.
Powiązania:
https://bibliotekanauki.pl/articles/1402380.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.58.Ji
87.57.U-
Opis:
Radiation is widely used many fields, especially in medical science. The shielding is the basic method of protection against unnecessary influence of radiation. One of the tools most commonly used in nuclear medicine is vial pig container. Usually lead is used as shielding material in vial pigs to cover radiation source, such as $Tc^{99m}$ which is the most widely used radiopharmaceutical in nuclear medicine. In this study boron carbide has been tested as an substitute of lead in vial pig. The measurement has been performed with the Geiger-Müller counter and the personal combined radiation detectors.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-335-B-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examples of Microstructure-Related Properties of Gallium Nitride
Autorzy:
Leszczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1967996.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
61.72.Vv
Opis:
The work provides a brief overview and the latest experimental results concerning the microstructure of gallium nitride. Because of the importance for the optoelectronic and electronic technologies, mainly problems related to the lattice mismatch between substrates and GaN layers are discussed. Three main substrates, sapphire, silicon carbide and high-pressure-grown bulk GaN crystals, are compared. Mosaicity, thermal strains and surface roughnesses of the GaN layers grown on those substrates are reported. The application of high-pressure technologies makes it possible to use temperatures higher by a few hundred degrees with respect to the atmospheric pressure for which the decomposition of gallium nitride occurs at temperatures below 1000°C. Annealing at pressures higher than 10 kbar and temperatures up to 1550° C causes modifications of the microstructure of GaN heteroepitaxial layers on sapphire. For example, their mosaicity decreases as observed by narrowing of the X-ray diffraction peaks. The implanted layers recover upon high-pressure annealing and give a strong dopant-related luminescence.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 653-661
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Band Mixing Effects in Quantum Well Magnetoexcitons
Autorzy:
Wysocki, R.
Bardyszewski, W.
Schoser, S.
Potemski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1968450.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ej
71.35.Ji
Opis:
The influence of intersubband mixing in quantum wells of semiconductors with zinc-blende structure is studied both experimentally and theoretically. A multiband magnetoexciton model is described which takes into account k∙p mixing between valence subbands and the effective Coulomb interaction for an arbitrary confinement potential shape. Theoretical results reproduce very well the photoluminescence excitation spectra of GaAs/AlGaAs single quantum wells of various widths. In particular, the characteristic avoided crossing between the lowest light-hole exciton Landau level and excited heavy-hole exciton Landau level occurring at σ¯ polarization is accurately described by our theory.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1067-1071
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Spin-Glass Transition in Semimagnetic Quantum Wells Based on Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te by Means of Optical Spectroscopy
Autorzy:
Zehnder, U.
Yakovlev, D. R.
Ossau, W.
Waag, A.
Landwehr, G.
Wojtowicz, T.
Karczewski, G.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1968455.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Ji
78.55.Et
Opis:
The spin-glass transition in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te epitaxial layers and bulk samples with 0.24 ≤ x ≤ 0.43 and in quantum well structures on the basis of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te were investigated by means of optical spectroscopy. Reduction of dimensionality of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te layers down to the quasi-two-dimensional case realized in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/Cd$\text{}_{1- y}$Mn$\text{}_{y}$Te heterostructures frustrates the spin-glass formation, which is in agreement with theoretical predictions. The spin-glass formation is also frustrated in the vicinity of interfaces between semimagnetic and nonmagnetic semiconductors in CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te quantum wells.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1075-1078
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the γ-Radiation on the Generation Characteristics of the YAlO_{3}:Nd Crystals
Autorzy:
Sugak, D. Yu
Matkovskii, A. O.
Grabovskii, V. V.
Prokhorenko, V. I.
Suchocki, A.
Durygin, A. M.
Solskii, I. M.
Shakhov, A. P.
Powiązania:
https://bibliotekanauki.pl/articles/1968884.pdf
Data publikacji:
1998-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Hj
61.72.Ji
Opis:
The results of investigation of the influence of γ-radiation by $\text{}^{60}$Co-source on the YAlO$\text{}_{3}$:Nd laser generation characteristics are presented in this paper. The significant decrease in the output energy after γ-irradiation was obtained. The energetic characteristics are restored after illumination of the γ-irradiated laser rods by 1000-10000 pulses of the pumping lamp light. The additional absorption spectrum is induced by γ-irradiation in the crystals. The nature of the created in this way colour centres is discussed. The mechanism of influence of the colour centres on generation properties of the crystals is discussed.
Źródło:
Acta Physica Polonica A; 1998, 93, 4; 643-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoexcitons in Semiconductor Quantum Rings with Complicated (Kanes) Dispersion Law
Autorzy:
Avetisyan, A.
Ghazaryan, A.
Djotyan, A.
Kirakosyan, A.
Moulopoulos, K.
Powiązania:
https://bibliotekanauki.pl/articles/1791288.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.-b
71.35.Ji
Opis:
The influence of the nonparabolicity of charge carriers dispersion law (Kane's dispersion) on a magnetoexciton energy spectrum in InSb quantum rings is theoretically investigated. The analytical expression for the energy spectrum of exciton in a narrow-gap semiconductor nanoring in a magnetic field is obtained. The Aharonov-Bohm oscillations in the energy of excited states are studied.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 826-828
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescent Spectroscopy of the Yb³⁺ Ions in the PbWO₄ Crystal
Autorzy:
Chukova, O.
Nedilko, S.
Powiązania:
https://bibliotekanauki.pl/articles/1030930.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
78.55.Hx
Opis:
Luminescent properties of the PbWO₄ crystals undoped and doped with the Yb³⁺ ions were studied. Emission spectra of the crystals consist of broadband matrix emission in 350-750 nm spectral range and narrow spectral lines caused by inner electron transitions in the impurity Yb³⁺ ions in 920-1040 nm spectral range. Analysis of the linear spectra has shown that Yb³⁺ ions form two types of emission centres. Structures of these centers are discussed taking into account possibility of the impurity ions incorporation in different positions (Pb and W sites) in the crystal lattice. Effects of the Yb³⁺ impurities on matrix emission were studied. Transfer of excitation energy from matrix to the Yb³⁺ decreases intensity of the red band of matrix emission. The Yb³⁺ impurities also increase intensity of the blue band by formation of additional Yb³⁺-induced channel of excitation of this band. The described effects of Yb³⁺ doping on properties of matrix emission are caused by the Yb³⁺ ions arranged in Pb positions.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 918-922
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Resolved Magnetophotoluminescence of Biased GaAs/AlGaAs Double Quantum Well Structure
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Potemski, M.
Henini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1811991.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Ji
78.67.De
Opis:
Time resolved photoluminescence of double quantum well structure was investigated versus electric and magnetic fields applied across the sample. The emission due to direct excitons (electron and hole are localized within the same quantum well) decays fast at the nanosecond timescale, whereas the recombination kinetics of indirect excitons is much slower and spreads over microseconds. The time evolution of indirect exciton emission is shown to be altered by application of either electric or magnetic field. This reflects the non-trivial effects of exciton localization which leads to the non-exponential decays of the indirect exciton emission.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1369-1374
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in Luminescence of Ce:yag Crystals Under Ionizing Radiation Treatment
Autorzy:
Kaczmarek, S. M.
Moroz, Z.
Kwasny, M.
Kisielewski, J.
Lukasiewicz, T.
Wojtkowska, J.
Rzewuski, H.
Powiązania:
https://bibliotekanauki.pl/articles/2008301.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
61.80.Ed
Opis:
Radiation induced changes in the luminescence spectrum under influence of UV light, γ-rays, electrons and protons for several concentrations of Ce$\text{}^{3+}$ ions as well as Mg$\text{}^{2+}$ ions in yttrium-aluminum garnet crystals were investigated. To irradiate with γ and electron as grown crystals were used while for proton irradiations the crystals were thermally annealed. For small concentrations of cerium ions (≈0.01 at.%) an increase in the luminescence (about 100%) was observed after gamma irradiation with a dose of 10$\text{}^{5}$ Gy. This increase was due to the growth in Ce$\text{}^{3+}$ ions concentration after γ-irradiation (≈50%), due to the Ce$\text{}^{4+}$ → Ce$\text{}^{3+}$ recharging reaction. For highly doped Ce:YAG crystals (0.1 at%, 0.2 at.%) also an increase, but much smaller (4%), for the Mg codoped crystals (0.1 at.%) was observed. After 1 MeV electron irradiation in the over-threshold type interaction a decrease in luminescence is observed due to the domination of the Ce$\text{}^{3+}$ → Ce$\text{}^{4+}$ ionization process. In the case of the proton irradiation, for small fluencies (≈10$\text{}^{13}$ particles/cm$\text{}^{2}$) an increase in luminescence is observed due to the domination of the recharging processes of Ce$\text{}^{4+}$ ions. For larger fluencies (>10$\text{}^{14}$ particles/cm$\text{}^{2}$) a decrease takes place due to a high level of radiation defects.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 953-964
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Annealing and Irradiation on the Optical Properties of Oxide Crystals
Autorzy:
Kaczmarek, S. M.
Berkowski, M.
Moroz, Z.
Warchoł, S.
Powiązania:
https://bibliotekanauki.pl/articles/2011084.pdf
Data publikacji:
1999-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
61.80.Ed
Opis:
We described results of the effect of annealing and irradiation treatments on the optical properties of Y$\text{}_{3}$Al$\text{}_{5}$O$\text{}_{12}$, YAlO$\text{}_{3}$, SrLaGa$\text{}_{3}$O$\text{}_{7}$, LiNbO$\text{}_{3}$, Gd$\text{}_{3}$Ga$\text{}_{5}$O$\text{}_{12}$, LaGaO$\text{}_{3}$, ZnSe, and LiF single crystals. Changes in absorption and luminescence are presented. Recharging processes of uncontrolled impurities (e.g. Fe$\text{}^{3+}$, Fe$\text{}^{2+}$, and Mn$\text{}^{2+}$), and active ions (e.g. Nd$\text{}^{3+}$, Dy$\text{}^{3+}$, Cr$\text{}^{4+}$, Cr$\text{}^{3+}$, and Ce$\text{}^{3+}$), as well as types of color centers produced in the crystals after a particular irradiation or annealing treatment are presented.
Źródło:
Acta Physica Polonica A; 1999, 96, 3-4; 417-427
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of Positron Implantation Profile in Different Materials
Autorzy:
Dryzek, J.
Powiązania:
https://bibliotekanauki.pl/articles/2042176.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
78.70.Bj
Opis:
The objective of this paper is experimental studies of the linear absorption coefficient, or mean penetration depth of positrons emitted from $\text{}^{22}$Na isotope in different materials. For this purpose we constructed a new experimental setup which allows us to scan the depth implantation profile of positrons. For the studied metals: Mg, Al, the obtained values of mean penetration depth coincide well with those which can be calculated using the mathematical formula commonly used but for Si and S the discrepancy has been observed similarly like for polymers.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 598-607
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trion Binding Energies and Wave Functions in Doped Quantum Wells
Autorzy:
Gładysiewicz, A.
Wójcik, K.
Wójs, A.
Quinn, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/2043713.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
Opis:
The energy spectra of negative trions (X$\text{}^{-}$=2e+h) in one-sided doped GaAs quantum wells are calculated. The maps of the trion binding energyΔ as a function of well width w, electron concentration n, and the magnetic field B are obtained. The dependence of the trion ground state ("bright singlet" versus "dark triplet") on those parameters is established.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 669-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers
Autorzy:
Leszczyński, M.
Teisseyre, H.
Suski, T.
Grzegory, I.
Boćkowski, M.
Jun, J.
Pałosz, B.
Porowski, S.
Pakuła, K.
Baranowski, J. M.
Barski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1952040.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
61.72.Vv
Opis:
Thermal expansion of gallium nitride was measured using high resolution X-ray diffraction. The following samples were examined: (i) single monocrystals grown at pressure of about 15 kbar, (ii) homoepitaxial layers. The main factor influencing both, the lattice parameters and the thermal expansion coefficient, are free electrons related to the nitrogen vacancies. The origin of an increase in the lattice constants by free electrons is discussed in terms of the deformation potential of the conduction-band minimum. An increase of the thermal expansion by free electrons is explained by a decrease of elastic constants.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 887-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies