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Wyszukujesz frazę "Stefański, P." wg kryterium: Autor


Tytuł:
Single-Ion Rare Earth Anisotropy in ThMn$\text{}_{12}$-Type Compounds
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/1931244.pdf
Data publikacji:
1994-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Gg
Opis:
The single-ion rare earth anisotropy was investigated in ThMn$\text{}_{12}$-type compounds. For this purpose the crystal electric field parameter values were studied. In these compounds, described by formula RFe$\text{}_{12-x}$T$\text{}_{x}$, R = rare earth, T = Ti, V, Cr, Mo, W and Si, the T atoms have strong crystallographic site preference changing the local crystal electric field potential which "sees" the rare earth ion. The crystal electric field potentials A$\text{}_{2}^{0}$ were calculated considering this site preference. The summations were performed taking into account the nearest neighborhood of the rare earth ion according to the recent results of band structure calculations. The charges of the surrounding Fe and T atoms were established applying the chemical bond model proposed by Pauling. The absolute value of A$\text{}_{2}^{0}$ decreases when the content of vanadium increases in 8(i) position, which is in agreement with experimental data. Localization of Si atoms in 8(j) and 8(f) causes a decrease in A$\text{}_{2}^{0}$. The $\text{}^{155}$Gd Mössbauer spectroscopy data confirm this fact. Miedema's "macroscopic" atom model of cohesion in alloys was applied for interpretation of the role of T atoms in the isomer shift and volume effects.
Źródło:
Acta Physica Polonica A; 1994, 85, 3; 615-621
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Reorientation and Exchange Coupling in the Dy$\text{}_{1-x}$Er$\text{}_{x}$Fe$\text{}_{10}$Si$\text{}_{2}$ Compounds
Autorzy:
Stefański, P.
Kowalczyk, A.
Skoryna, D.
Szlaferek, A.
Wrzeciono, A.
Powiązania:
https://bibliotekanauki.pl/articles/1929845.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Gg
Opis:
The structural and magnetic properties of Dy$\text{}_{1-x}$Er$\text{}_{x}$Fe$\text{}_{10}$Si$\text{}_{2}$ are investigated. X-ray analysis reveals that these compounds are of the tetragonal ThMn$\text{}_{12}$ structure. In this structure the rare earth atoms occupy one crystallographic position 2(a). The unit cell contains 26 atoms. The spin reorientation temperature, T$\text{}_{SR}$, was measured from the temperature dependence of the initial susceptibility using an ac bridge of mutual inductance of the Harsthorn type. Dy$\text{}^{+3}$ and Er$\text{}^{+3}$ have opposite contributions to the entire magnetic anisotropy. The spin reorientation temperature is found to be about 271 K in DyFe$\text{}_{10}$Si$\text{}_{2}$ and 48 K in ErFe$\text{}_{10}$Si$\text{}_{2}$. The values are discussed applying the crystal field model. The value of the rare earth-transition metal exchange coupling constant J$\text{}_{RFe}$/k$\text{}_{B}$ derived from the mean-field model analysis of the Curie temperature is about -13 K. The Fe-Fe exchange integral is much higher and is equal to about 75 K.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 259-262
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badanie pracy przy podkrzesywaniu drzew - czasochlonnosc i wydajnosc
Autorzy:
Giefing, D.F.
Holota, R.
Stefanski, P.
Srednicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/812975.pdf
Data publikacji:
1996
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
czasochlonnosc
podkrzesywanie drzew
wydajnosc pracy
lesnictwo
zabiegi pielegnacyjne
Źródło:
Sylwan; 1996, 140, 01; 37-44
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ground State Properties of Tb$\text{}^{3+}$ Ion in TbNi$\text{}_{10}$Si$\text{}_{2}$
Autorzy:
Stefański, P.
Suski, W.
Wochowski, K.
Mydlarz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1964565.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Gg
Opis:
Ground state properties of Tb$\text{}^{3+}$ ion were investigated in the tetragonal ThΜn$\text{}_{12}$-type TbNi$\text{}_{10}$Si$\text{}_{2}$ compound on the basis of temperature dependence of the paramagnetic susceptibility and magnetization measurements. The rare earth temperature dependence of the susceptibility was calculated using the Van Vleck equation. The Γ$\text{}_{t5}^{(1)}$ doublet is suggested to be a ground state separated by 9 K from the first excited singlet Γ$\text{}_{t1}^{(2)}$. The magnetic moment associated with the ground state doublet agrees with saturation magnetization data at 4.2 K. The overall crystal field splitting is estimated to be 105 K.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 281-284
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coqblin-Schrieffer Impurity with Local Exchange Coupling: a Perturbative Approach
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/2013008.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Hf
71.20.Eh
72.15.Qm
75.20.Hr
Opis:
The Coqblin-Schrieffer one-impurity model with the additional local exchange interaction is studied within diagrammatic approach. The Ruderman-Kittel-Kasuya-Yoshida-type local exchange interaction between f electrons of the impurity and a channel of conduction electron l=0 partial waves is treated in the molecular field approximation. The perturbation expansion resummation for the Coqblin-Schrieffer hybridization mediated interaction vertex part is carried out in the ladder approximation yielding the formula for the Kondo temperature T$\text{}_{K}$ decreasing with increased local exchange. Moreover, the temperature divergence of the susceptibility at T$\text{}_{K}$ is shifted towards T=0. For some critical strength of the local exchange interaction the susceptibility approaches a Curie-type dependence as for an uncompensated impurity magnetic moment. A relation to the "Kondo disorder" model, which leads to the non-Fermi-liquid behavior, is discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 385-388
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy method for position stability analysis of critical points of robot manipulators
Metoda energetyczna analizy stateczności punktów krytycznych manipulatorów
Autorzy:
Szumiński, P.
Kapitaniak, T.
Stefański, A.
Powiązania:
https://bibliotekanauki.pl/articles/280647.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
critrical point
load of driving system
position stability
Opis:
An energy method for the position stability analysis of critical points (equilibrium positions) of dynamical systems with an arbitrary finite number of degrees of freedom is presented. The method proposed consists in the analysis of the potential energy balance of a perturbation of an arbitrary number of generalised co-ordinates of the dynamical system in order to establish the energy stability of individual degrees of freedom and of the whole system. In the case of mechanical systems, the position stability criterion, understood as minimisation of loads of driving systems with conservative forces, is discussed. Some examples of application of the method to the position stability analysis of critical points of one- and two-degree-of-freedom systems are analysed.
W artykule przedstawiono metodę energetyczną analizy stateczności punktów krytycznych (położeń równowagi) układów dynamicznych o dowolnej skończonej liczbie stopni swobody. Proponowana metoda polega na analizie bilansu energii potencjalnej zaburzenia dowolnej liczby współrzędnych uogólnionych układu dynamicznego w celu określenia stateczności energetycznej poszczególnych stopni swobody oraz całego układu. W przypadku układów mechanicznych przedstawiono kryterium stateczności w sensie minimalizacji obciążeń układów napędowych siłami zachowawczymi. Przedstawiono przykłady zastosowania metody dla celów analizy stateczności punktów krytycznych układów o jednym i dwóch stopniach swobody.
Źródło:
Journal of Theoretical and Applied Mechanics; 2004, 42, 1; 139-162
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interplay of Kondo and Fano Resonance in Electronic Transport in Nanostructures
Autorzy:
Bułka, B. R.
Stefański, P.
Tagliacozzo, A.
Powiązania:
https://bibliotekanauki.pl/articles/2043700.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.-b
72.15.Qm
75.20.Hr
Opis:
Quantum interference and electronic correlations are processes relevant for electronic transport in nanostructures. We present theoretical studies of transport for various models, which take into account these processes and describe the Fano resonance as well as many-body effects like the Kondo resonance. The results are compared with transport measurements performed on a small quantum dot strongly coupled to electrodes, a large semi-open quantum dot, a side-attached quantum dot to a quantum wire systems and a quantum dot embedded in the metallic ring. We show how conductance characteristics of the Kondo and the Fano resonance are modified in different situations.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 555-569
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Air aerosol sampling station AZA-1000 at Polish Polar Station in Hornsund, Spitsbergen
Autorzy:
Mysłek-Laurikainen, B.
Matul, M.
Mikołajewski, S.
Trzaskowska, H.
Preibisz, Z.
Garanty, I.
Kubicki, M.
Rakowski, P.
Krynicki, T.
Stefański, M.
Powiązania:
https://bibliotekanauki.pl/articles/148535.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
air sampling
radioactive aerosols
radioactive air pollution
radionuclides
polar air monitoring
Opis:
The high volume air sampler AZA-1000 was built in the Environmental Protection Laboratory of the Andrzej Sołtan Institute for Nuclear Studies. In July 2002, this air sampler AZA-1000 was installed in the Polish Polar Observatory of the Polish Academy of Science in Hornsund, Spitsbergen. The device was built with numerous specific features which make possible to operate such station in extra difficult climatic conditions of polar region. Since July 2002, radioactive aerosols were collected at the Petrianov filter tissue FPP-15-1.5 and measured using high resolution g spectrometry in the Environmental Protection Laboratory at Świerk. The concentration of the airborn, cosmogenic radionuclide 7Be and of other natural and man maid radionuclides like 137Cs was determined. A comparison of the preliminary results with those from the ASS-500 sampling station operating at Świder is presented.
Źródło:
Nukleonika; 2006, 51, 2; 137-140
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Level Occupancy Anomalies in a Double QD System
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/1810305.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
Opis:
A double quantum dot system is considered in the presence of the electron intra-Coulomb U interactions within the dots and inter-Coulomb $U_{12}$ interactions between them. We show that both for spinless and spinfull electrons the dots occupancy anomalies are encountered and caused by electron correlations. This non-monotonic behavior strongly deviates from usual level filling at the Coulomb blockade. For spinfull electrons the inter-dot interaction modifies also on-site electron correlations.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 92-94
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Dependent Fano Resonances in a Rashba System with Coulomb Interactions
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/2048075.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
72.25.Dc
73.40.Sx
Opis:
The effects of interplay of interference of quantum mechanical electron waves and their mutual Coulomb interactions are investigated in the device composed of interacting quantum dot attached to polarized leads via quantum point contacts with the Rashba interaction. The Zeeman-split dot sub-levels form two interfering channels and as a result spin dependent Fano resonances arise in the conductance through the system. The Coulomb repulsion between the channels modifies the width and shape of the Fano resonances as compared to the non-interacting case. We formulate the Fano expression dependent on the dot's occupancy regulated by the Coulomb interactions.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 644-647
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy balance of two synchronized self-excited pendulums with different masses
Bilans energii dwóch zsynchronizowanych wahadeł samowzbudnych o różnych masach
Autorzy:
Kapitaniak, T.
Czołczyński, K.
Perlikowski, P.
Stefański, A.
Powiązania:
https://bibliotekanauki.pl/articles/280340.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
coupled oscillators
pendulum
synchronization
Opis:
We consider the synchronization of two self-excited pendulums with different masses. We show that such pendulums hanging on the same beam can show almost-complete (in-phase) and almost-antiphase synchronizations in which the difference of the pendulums displacements is small. Our approximate analytical analysis allows one to derive the synchronization conditions and explains the observed types of synchronizations as well as gives an approximate formula for amplitudes of both the pendulums and the phase shift between them. We consider the energy balance in the system and show how the energy is transferred between the pendulums via the oscillating beam allowing synchronization of the pendulums.
Artykuł prezentuje analizę zjawiska synchronizacji dwóch wahadeł samowzbudnych o różnych masach. Pokazano, że jeśli takie wahadła zostaną zawieszone na wspólnej, ruchomej podstawie, zachodzi zjawisko ich (prawie) zupełnej lub (prawie) antyfazowej synchronizacji. Analiza bilansu energetycznego układu pozwala na określenie parametrów układu w stanie synchronizacji (amplitudy drgań i przesunięcia fazowe). Analiza bilansu energetycznego wyjaśnia także mechanizm synchronizowania się ruchu wahadeł: stały przepływ strumienia energii od jednego wahadła, via wspólna ruchoma podstawa, do drugiego wahadła powoduje, że ruch układu jest okresowy, a przesunięcia fazowe pomiędzy wahadłami przyjmują stałe, charakterystyczne wartości.
Źródło:
Journal of Theoretical and Applied Mechanics; 2012, 50, 3; 729-741
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality Expectations of Mobile Subscribers
Autorzy:
Gilski, P.
Stefański, J.
Powiązania:
https://bibliotekanauki.pl/articles/307922.pdf
Data publikacji:
2015
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
cellular networks
mobile communication
quality of experience
quality of service
wireless communication
Opis:
Mobile systems, by nature, have finite resources. Radio spectrum is limited, expensive and shared between many users and services. Mobile broadband networks must support multiple applications of voice, video and data on a single IP-based infrastructure. These converged services each have unique traffic holding and quality requirements. A positive user experience must be obtained through efficient partitioning of the available wireless network resources. The 3rd Generation Partnership Project (3GPP) has developed a comprehensive Quality of Service (QoS) parameter to address this problem. The regular control of service quality is critical for operators to ensure user Quality of Experience (QoE), establish new business models and monetize services. It enables operators to employ fair-use resource policies and maintain network performance during peak traffic times. Wireless mobile communication is tending towards an integrated system of Internet and telecommunication technologies, where mobile users move freely anytime and everywhere. They desire to communicate with any device using the best service available. In this paper QoS management issues in mobile communication are described. The authors present an insight into subscriber behavior and related factors that affect the QoE of mobile data services.
Źródło:
Journal of Telecommunications and Information Technology; 2015, 1; 15-19
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signatures of Majorana States in Electron Transport through a Quantum Dot Coupled to a Topological Wire
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/1384812.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.-b
73.23.Hk
73.21.La
74.78.Na
Opis:
We consider theoretically a system composed of a quantum dot coupled to a topological superconducting wire. The dot, being in Coulomb blockade (CB) regime is additionally coupled to the normal leads. The topological wire hosts Majorana states, which, as we show, characteristically modifies conductance through the dot. An unpaired Majorana state in the wire causes a unique temperature dependence of zero bias conductance vs. gate voltage. It decreases in-between CB peaks and on the sides of the peaks from the plateau at ~ e²/2h when temperature increases. At the same time conductance increases at the CB peak positions. It is accompanied by zero bias anomaly in differential conductance. For finite overlap of Majorana states in the wire the zero bias anomaly disappears. Instead, two characteristic Fano resonances of opposite symmetry appear, positioned mirror-symmetrically with respect to zero bias.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 198-200
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Survey of Radio Navigation Systems
Autorzy:
Gilski, P.
Stefański, J.
Powiązania:
https://bibliotekanauki.pl/articles/227025.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radio navigation
radio communication
satellite navigation systems
radiofrequency identification
Opis:
At present, there is a growing demand for radio navigation systems, ranging from pedestrian navigation to consumer behavior analysis. These systems have been successfully used in many applications and have become very popular in recent years. In this paper we present a review of selected wireless positioning solutions operating in both indoor and outdoor environments. We describe different positioning techniques, methods, systems, as well as information processing mechanisms.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 43-48
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Can the Digital Surpass the Analog: DAB+ Possibilities, Limitations and User Expectations
Autorzy:
Gilski, P.
Stefański, J.
Powiązania:
https://bibliotekanauki.pl/articles/226204.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
audience
broadcasting
DAB+
digital audio broadcasting
electronic media
radio
telecommunications
Opis:
Radio is by far the most accessible medium. With its mobility and availability, it attracts listeners by its simplicity and friendliness. The present information situation is characterized by the convergence of computers, mobile devices, telecommunication and broadcasting technologies and the divergence of different ways of delivering and storing media. Consumers are overwhelmed by new electronic gadgets appearing every year. They are astonished by new technical innovations that are being designed to ease their life and change their habits. Even the broadcasting sector itself is facing significant changes, especially a growing competition between the private and public sector. This article reviews the current status of analog and digital broadcasting technologies. It analyzes a case study of user expectations related with today’s digital media, particularly radio transmission. We discuss the principal possibilities, limitations and user expectations related with digital audio broadcasting, as well as the economic, technological, regulatory and frequency management factors.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 4; 353-361
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł

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