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1
Content available remote The Wave Packet Study of Exciton Dynamics in the ZnSe-ZnTe Quantum Well
100%
Bała P.
Acta Physica Polonica A
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1998
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tom 94
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nr 2
240-244
EN
In this paper we perform a detailed study of the formation and the dynamics of the exciton in the ZnSe/ZnTe quantum well taking into account two-particle nature of the process. The electron-hole interaction is included in the model through the electrostatic potential, which results in a nonlinear coupling of the electron and hole equations of motion. The coupled time-dependent Schrodinger equation describing the electron and hole dynamics is integrated numerically. The detailed dynamics of the excitonic electron-hole pair in the quantum well is presented for different uniform electric field applied across the structure.
2
Content available remote Dynamics of Hot Electrons in ZnSe-ZnTe Double Barrier Heterostructures
100%
Bała P.
Acta Physica Polonica A
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1997
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tom 92
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nr 4
709-714
EN
In this paper we perform a detailed study of the transport of hot electrons in the double barrier heterostructures with the presence of a collector barrier. This system is considered as a double barrier resonant tunneling device. The electron is described by time-dependent Schrodinger equation, which allows us to study detailed dynamics of the carriers. The influence of an energy step in the collector area of the device on the tunneling probability is investigated. The significant role of dissipation due to electron-phonon interactions is presented.
3
Content available remote Photon Assisted Tunneling in ZnSe-ZnTe Double Barrier Heterostructures
100%
Bała P.
Acta Physica Polonica A
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1996
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tom 90
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nr 5
1002-1006
EN
The tunneling phenomena in double barrier heterostructures can be affected by various effects. In this paper the effect of the intense THz radiation on the electron dynamics in the double barrier heterostructure is investigated. For the low frequency radiation the shift in the energy scale of the resonant tunneling peak together with its broadening is observed. For the high radiation frequency the multipeak structure is obtained. The interaction with radiation quanta leads to sequential tunneling and the transmitted wave function consists of single separated wave packets.
4
Content available remote Crystallography and Morphology of Chromium Rich Eutectic Carbides in an As-Cast Fe-Cr-C Alloy Crystallized in Non-Equilibrium Conditions
51%
Wieczerzak K. , Bała P. , Tokarski T. , Gajewska M.
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nr 4
1007-1009
EN
The crystallography and microstructure of eutectic carbides crystallizing in non-equilibrium conditions in hypoeutectic Fe24Cr0.8C have been studied by light microscopy, scanning electron microscopy, and transmission electron microscopy. The alloy was synthesized in an arc furnace in high purity argon atmosphere and crystallized on water-cooled copper mould. Greater thermal gradient in regions close to water-cooled, copper mould in comparison with top of the ingot gives a formation of eutectic carbides with two morphologies: large polygonal carbides and surrounding them much smaller, plate-like carbides instead of rod-like carbides, observed in top of the ingot. There was no evidence for influence of non-equilibrium crystallization to the formation of types of carbides different than M₂₃C₆.
5
Content available remote Time Dependent Tunneling in Double-Barrier ZnSe/ZnTe Structures
51%
Bała P. , Kwiatkowski J. , Bała W.
Acta Physica Polonica A
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1992
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tom 82
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nr 4
649-652
EN
The wave-packet time dependent quantum mechanics is used to calculate tunneling probability through a double-barrier ZnSe/ZnTe structure. The time dependent I-V characteristics are obtained for several structures. The resonant peaks are observed and their changes with the barrier parameters are monitored.
6
Content available remote Tunneling in Double-Barrier Heterostructures - Comparison of Time-Dependent and Stationary Approach
51%
Bała P. , Ryszewski R. , Bała W.
Acta Physica Polonica A
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1993
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tom 84
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nr 4
685-688
EN
The tunneling probability through a double-barrier ZnSe/ZnTe structure is calculated using both wave-packet time dependent quantum mechanics and stationary planar-wave approximation. The obtained I-V characteristics are compared and very good consistence in resonant peaks width and position is observed. The absolute value of tunneling probability obtained in time-dependent and stationary approach is also similar.
7
Content available remote The Mössbauer Spectroscopy Studies οf Cementite Precipitations during Continuous Heating from As-Quenched State of High Carbon Cr-Mn-Mo Steel
51%
Krawczyk J. , Bała P. , Hanc A.
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nr 6
1651-1657
EN
This work complements the knowledge concerning the kinetics of cementite precipitation during tempering. Investigations were performed on 120MnCrMoV8-6-4-2 steel. The samples of investigated steel were austenitized at the temperature of 900°C and quenched in oil. Then four of five samples were tempered. Tempering consisted of heating the samples up to chosen temperatures at the heating rate of 0.05°C/s and fast cooling after reaching desired temperature. This work presents the results of investigations performed carried out using the Mössbauer spectroscopy technique and their interpretation concerning cementite nucleation and growth during tempering. The values of hyperfine magnetic field on ^{57}Fe atomic nuclei, determined for the third component of the Mössbauer spectrum as regards to its intensity, indicate that these are the components coming from ferromagnetic carbides. Big differences in hyperfine magnetic fields coming from Fe atoms existing in the structure of carbides, measured on samples heated up to the temperatures of 80°C and 210°C, in comparison with values for ^{57}Fe atoms precipitated from carbides during heating up to the temperature of 350°C and 470°C, allow to state that these are the carbides of different crystal structure. The influence of hardened steel heating temperature on cementite precipitation was determined. The Mössbauer spectroscopy was applied not only for magnetic hyperfine fileld studies, but also to analyze the values of quadrupole splitting and isomeric shift, which resulted in significant conclusions concerning the changes in cementite precipitations morphology, chemical composition and the level of stresses being present in this research.
8
Content available remote The Mössbauer Spectroscopy Studies of ϵ to Cementite Carbides Transformation during Isothermal Heating from As-Quenched State οf High Carbon Tool Steel
51%
Bała P. , Krawczyk J. , Hanc A.
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nr 6
1641-1650
EN
This work presents results of investigations using the Mössbauer spectroscopy technique and their interpretation concerning transformation of ϵ to cementite carbides during tempering in relation to the previously conducted dilatometric, microscopic and mechanical investigations. Investigations were performed on 120MnCrMoV8-6-4-2 steel. The influence of the tempering time on nucleation and solubility of ϵ carbides, and on cementite nucleation and growth, was determined. The analysis of phase transformations during various periods of tempering using the Mössbauer spectroscopy technique made possible to reveal fine details connected with the processes.
9
Content available remote Effect of Accumulation Layer on Tunneling in ZnSe-ZnTe Double Barrier Heterostructures
51%
Bała P. , Ryszewski R. , Bała W.
Acta Physica Polonica A
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1995
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tom 87
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nr 2
341-344
EN
The tunneling probability in double barrier heterostructures can be af­fected by various effects. One of the most significant is presence of the ac­cumulation layer placed before the structure. The presented time-dependent results show that charge trapped in the accumulation region oscillates in the triangular quantum well and tunnels sequentially through the double barrier structure resulting in periodical changes of the charge density right to the heterostructure.
10
Content available remote X-ray Diffraction and EBSD Study of Al-Ti-Co-Ni-Fe High-Entropy Alloy
38%
Górecki K. , Bała P. , Cios G. , Stępień M. , Kozieł T. , Wieczerzak K. , Tokarski T.
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|
nr 4
991-992
EN
Al₁₅Ti₂₀Co₂₀Ni₂₅Fe₂₀ alloy, synthesized in an arc furnace, was characterized by microscopic investigations, X-ray diffraction and electron backscatter diffraction techniques. Theoretical assumptions indicate a dual-phase crystal structure fcc+bcc. It was shown that dendrites and eutectic are bcc phase, and the interdendritic region is fcc phase.
11
Content available remote Structures of Cu-Based Glass Forming System Doped with Iron
38%
Kozieł T. , Latuch J. , Czeppe T. , Ratuszek W. , Cios G. , Zielińska-Lipiec A. , Bała P.
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|
nr 4
913-915
EN
The effects of iron additions on the structure of (Cu_{0.47}Ti_{0.34}Zr_{0.11}Ni_{0.08})_{100-x}Fe_{x} (x=0, 1.5, 3, 6) glass forming system are presented. The alloys were synthesized by arc melting of high purity elements and melt spun to form: rapidly quenched ribbons. X-ray diffraction studies showed the amorphous structure of the base and Fe-containing alloys, confirmed by the presence of exothermic peaks on differential scanning calorimetry curves. Bulk samples in the form of rods (Φ3×55 mm) were cast using a suction casting unit attached to the arc melter. Structural investigations revealed partial crystallization of the base Cu₄₇Ti₃₄Zr₁₁Ni₈ alloy. Iron additions significantly decreased the glass forming ability of the alloy, leading to primary crystallization of dendrites.
12
Content available Strain Induced Recrystallization in Hot Forged Inconel 718 Alloy
32%
Krawczyk J. , Łukaszek-Sołek A. , Śleboda T. , Bała P. , Bednarek S. , Wojtaszek M.
|
13
Content available The Characterization Of Cast Fe-Cr-C Alloy
32%
Wieczerzak K. , Bała P. , Stępień M. , Cios G. , Kozieł T.
|
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nr 2
14
Content available Microstructure of Cast Ni-Cr-Al-C Alloy
32%
Cios G. , Górecki K. , Bała P. , Stępień M.
|
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nr 1
15
Content available Improper Interpretation of Dilatometric Data for Cooling Transformation in Steels
26%
Pawłowski B. , Dziurka R. , Bała P.
|
16
Content available The Dilatometric Analysis of the High Carbon Alloys from Ni-Ta-Al-M System
23%
Bała P.
|
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