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Wyszukujesz frazę "G20" wg kryterium: Temat


Tytuł:
1,1-Dithiolenes: the Good, the Not Bad, and the Ugly
Autorzy:
Cassoux, P.
Bowlas, C. J.
Lahlil, K.
Moradpour, A.
Bonvoisin, J.
Launay, J.-P
Powiązania:
https://bibliotekanauki.pl/articles/1933327.pdf
Data publikacji:
1995-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.20.-t
82.40.-g
82.45.+z
33.10.-n
82.30.-b
Opis:
A series of 1, 1'-dithiolate ligands were used in the attempted preparation of metal complexes. These bidentate sulphur ligands were subsequently used in aromatic nucleophilic substitution reactions giving rise to several novel organic donor molecules. The electrochemistry data of two of the donors and their subsequent use in the preparation of donor-acceptor compounds is presented. One donor-acceptor compound exhibited high room temperature conductivity (up to 900 S cm$\text{}^{-1}$) and remained metallic down to low temperature. One donor containing two tetrathiafulvalene units was studied by near infrared absorption spectroscopy. An intervalence transition in the monocation form of this donor was observed, indicating that it behaves as a class II mixed valence compound.
Źródło:
Acta Physica Polonica A; 1995, 87, 4-5; 743-748
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive Modulation Amplitude in 2D Spectral-Spatial EPR Imaging
Autorzy:
Czechowski, T.
Samolej, A.
Baranowski, M.
Boś-Liedke, A.
Chlewicki, W.
Jurga, J.
Tadyszak, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030422.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.-v
42.30.Wb
75.20.-g
42.30.Va
Opis:
A study concerning the image quality in Electron Paramagnetic Resonance Imaging (EPRI) in 2D spectral-spatial (2D SSI) experiments is presented. The aim of the measurements is to improve the signal to noise ratio (SNR) of the projections by applying a more consciously selected modulation amplitude parameter. Data is gathered by applying three constant and one adaptive modulation amplitude. The three fixed modulation amplitudes values are leading to undermodulated (0.01 G), partially overmodulated (0.15 G) and fully overmodulated (0.65 G) projections. The study demonstrates the advantages of the adaptive method, which involves selecting different and dependent on cosine function modulation amplitudes for each projection. The study is performed on a phantom containing four tubes of LiPc and TCNQ, characterized by a different peak to peak linewidth and spin concentration.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 710-712
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis Of The Current Trends Of Gold And Foreign Exchange Reserves Of The G20 Countries
Autorzy:
Derkach, Tatyana
Powiązania:
https://bibliotekanauki.pl/articles/1402370.pdf
Data publikacji:
2020
Wydawca:
Wyższa Szkoła Ekonomiczno-Humanistyczna w Bielsku-Białej
Tematy:
gold and foreign exchange (international) reserves (gold reserves) of the G20 countries
19 countries of the Eurozone
rating of the G20 countries in terms of dynamics and variations in gold and FX reserves
pair correlation of changes in international reserves among the G20 countries
Opis:
During periods of instability, the availability of reserves in the national economy of a country, necessary to overcome crises and repay their negative effects, is of great importance. The economic policy of the G20 countries on the formation of international reserves will give us a general idea of the main trends in this direction. The change in the structure of gold and FX reserves among the group of G20 countries in 2007-2019 is analyzed, the average annual absolute level of gold reserves and their growth have been determined, the amplitude of fluctuations, average deviation and coefficient of variation of gold reserves of the G20 countries have been determined, based on the calculation of the pairwise linear correlation of the gold and foreign exchange dynamics between the G20 countries, the similarities and differences in the implementation of the state policy on international reserves management were determined.
Źródło:
MIND Journal; 2020, 10; 1-19
2451-4454
Pojawia się w:
MIND Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aspects of Magnetism in Heavy-Electron Metals
Autorzy:
Ott, H. R.
Powiązania:
https://bibliotekanauki.pl/articles/1860764.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
75.20.Hr
75.30.-m
75.30.Mb
Opis:
For some time it was believed that heavy-mass electrons at low temperatures, in special rare-earth and actinide compounds, were due to a particular suppression of magnetic order in these materials. Various experiments reveal, however, that magnetic order may occur from a heavy-electron state and that also a heavy-electron state may develop in the presence of a magnetically-ordered matrix. Even in materials with no sign of a cooperative phase transition, microscopic experimental probes give evidence for strong magnetic correlations, involving only very tiny (< 10^{-1} μ_{B}) ordered moments, however. All these experimental observations indicate that the heavy-electron state cannot always be regarded as a simple Fermi liquid in the usual sense. Various interactions of similar strength need to be considered. It is suggested that the balance of these interactions may lead to electronic inhomogeneities in k space. Both in magnetically-ordered or superconducting systems, unexpected electronic degrees of freedom appear to exist. In other cases experimental observations suggest magnetic inhomogeneities in real space which are not simply due to chemical inhomogeneities. Different examples of these various possibilities are demonstrated and discussed.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 7-19
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
BRICS in the G20? The Involvement of Rising Powers in the Premier Forum of Global Governance
Autorzy:
Rewizorski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/2091837.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Warszawski. Wydział Nauk Politycznych i Studiów Międzynarodowych
Tematy:
International relations
Politics
Global management
G20 summits
Stosunki międzynarodowe
Polityka
Zarządzanie globalne
Szczyt G20
Opis:
Amongst the examples of structures filling up the spectrum of relationships between states and non-state actors in global governance, one can distinguish informal forums of international co-operation. The core position amongst them is occupied by the Group of Twenty (G20). This paper is devoted to the issue of the participation of BRICS in global governance institutions, above all the G20, which develops the summitry process at the political leader and ministerial levels. Attention is drawn to the BRICS group as the leading emerging economies and political powers at the regional and international levels, extending their influence within the G20. This paper highlights the increasing activity of emerging economies in this premier forum of global governance and explores the possibilities of BRICS members developing co-ordinated positions in the G20.(original abstract)
Źródło:
Stosunki Międzynarodowe - International Relations; 2016, 52, 1; 211-222
0209-0961
Pojawia się w:
Stosunki Międzynarodowe - International Relations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon-Encapsulated Magnetic Nanoparticles Based on Fe, Mn, and Cr for Spintronics Applications
Autorzy:
Szczytko, J.
Osewski, P.
Bystrzejewski, M.
Borysiuk, J.
Grabias, A.
Huczko, A.
Lange, H.
Majhofer, A.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047686.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
75.75.+a
75.20.En
75.30.Cr
75.50.Bb
Opis:
We succeeded in the arc-plasma synthesis of carbon-encapsulated Fe, Cr, and Mn-based nanoparticles. The transmission electron microscopy, Mössbauer spectra (of iron) and SQUID magnetometry results demonstrate that the products of the synthesis contain metals and its carbides. The nanoparticles show ferromagnetic or superparamagnetic behavior at high temperatures, which is demanded for nano-spintronics applications.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 305-310
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Transfer Dynamics in Atom-Metal Surface Collisions
Autorzy:
Wiertel, M.
Taranko, R.
Taranko, E.
Powiązania:
https://bibliotekanauki.pl/articles/2011189.pdf
Data publikacji:
1999-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.Rf
78.70.-g
82.65.Pa
Opis:
We study the charge exchange in atom-metal collisions in the framework of the generalized time-dependent Anderson-Newns model. The electron correlations and correlated hopping are treated within the mean-field approximation. The resulting one-particle model with an effective spin-dependent atom-surface coupling is used to study the charge transfer in scattering of Na and Li atoms on metal surfaces. It is shown that the effective occupation dependent atom-surface coupling influences mainly the expectation values for producing positive, neutral, and negative particles for small work functions and high atom velocities. It is also shown that the temperature dependence of these expectation values is more visible, especially for magnetic solutions.
Źródło:
Acta Physica Polonica A; 1999, 96, 6; 769-783
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational material analysis of structural and hemodynamic model of coronary stent by CFD/FEA in computer aided mechanical engineering approach
Autorzy:
Karaçal, Ö.
Powiązania:
https://bibliotekanauki.pl/articles/1070469.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
81.70.Bt
82.20.Wt
87.10.Kn
87.15.A-
Opis:
With the development of new technologies, it is very popular to use a coronary stent that is a small mesh tube-shaped medical device deployed to treat narrow or weak arteries as part of a procedure called percutaneous coronary intervention. Several aspects, such as stent design, stent wire type, mechanical and material characteristics of stent have different influences on stent intervention. It has not been reported about what impacts on stent struts by the hemodynamic behavior on stent material and very few numerical studies have considered both the mechanical and hemodynamic impact of stent implementation. Computational simulation method for realization of realistic structural and hemodynamic micro environment model in this research provided valuable results of long-term functional knowledge of stent material behavior that are time consuming and expensive to determine otherwise. Computational fluid dynamics and finite element analysis simulation models were investigated and developed to evaluate engineering properties that affect stent functional attributes. These characteristics are dependences of material properties on blood flow conditions such as structural load, shear-strain rate, radial strength, and wall shear stresses, which need to be scientifically explored. To understand the material (Fe-18Cr-14Ni-2.5Mo as stainless steel 316LVM) mechanical performance of the stent, a finite element analysis simulation model was established when exposed to pulsatile blood pressure. In this study, computational fluid dynamics model was generated to calculate the wall shear stresses and strain distribution in stented vessel carrying blood to heart. The analytical analysis of mechanical and hemodynamic conduct of a stent in this investigation may help for better designs of stent, and provide deeper comprehension to support clinical cardiovascular surgeons and guide potential therapeutic strategies.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 249-251
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consequences of Confinement Conditions on Absorption in Molecular Nanofilms
Autorzy:
Šetrajčić, I.
Rodić, D.
Šetrajčić, J.
Šetrajčić-Tomić, A.
Vučenović, S.
Powiązania:
https://bibliotekanauki.pl/articles/1030578.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.-y
71.35.Aa
77.22.Ch
77.55.-g
78.20.Bh
78.68.+m
81.07.Nb
Opis:
This paper presents a model of molecular ultrathin crystalline film and analysis of dielectric properties of these spatially very restricted structures. Using the two-time dependent Green functions the energy spectrum and possible exciton states were determined and the dynamic permittivity was calculated. It was shown that the appearance of localized states in the boundary layers of the film depend on the thickness and the changing values of parameters in the border areas of the film. These localized states define schedule and determine the number of resonant absorption lines in the infrared area of the external electromagnetic radiation.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 129-139
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper Deficiency - a Crystallochemical Nature of Ce-Doped Gd$\text{}_{2}$CuO$\text{}_{4}$ Phase. Part II
Autorzy:
Horyń, R.
Bukowska, E.
Sikora, A.
Wołcyrz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2041471.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Two samples of nominal composition Gd$\text{}_{1.80}$Ce$\text{}_{0.15}$CuO$\text{}_{4.0}$ and Gd$\text{}_{1.85}$Ce$\text{}_{0.15}$CuO$\text{}_{4.075}$ were subjected for a long-term treatment in air at 1100°C, comprised with a precise control of their weights vs. time of the treatment applied. The gravimetric analysis and the iodometric titration, both showed a deficiency on Cu-site, steadily increasing vs. time with a slight tendency to a saturation. The X-ray analysis of the resulting products showed that even after 272 h of sintering, the samples remained single phase of the "214" structure type. Refinement of their crystal structures as well as density measurements, both allowed confirming Cu deficient structure constitution of these samples. Results of dc-magnetization measurements, performed prior to reduction of the sample's overall oxygen content, did not show any sign of superconductivity down to 4.2 K. These preliminary results indicate that copper deficiency, developing during synthesis, may occur to be a decisive factor for the reported lack of superconductivity in Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase. Oxygen content reduction and further tests on the samples obtained are in progress.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 733-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupled States of the System of Two Free Electrons on a Single Star
Autorzy:
Walcerz, S.
Lulek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1891910.pdf
Data publikacji:
1991-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.20.+b
71.45.-d
75.10.Lp
75.20.-g
Opis:
A classification scheme of quantum states for the system of two free electrons in a cubic box, confined to a single star of quasi-momentum is proposed within a Racah-Wigner type of approach. Coupling of angular momenta of the atomic case is here substituted by Mackey theorem for transitive representations, which provides a crystalline analogue of orbital angular momentum - the resultant orbit of the geometric symmetry group. The action of the Pauli group is combined with that of the octahedral group which yields the connection between spin (i.e. the singlet or triplet pairing of electrons) and statistic of the positional factor. Resultant singlets and doublets - irreducible representations of the octahedral group, exhibit an ordinary Landau diamagnetic behaviour, whereas triplets are paramagnetic. A relation between the Mackey star and the star of resultant momentum is discussed.
Źródło:
Acta Physica Polonica A; 1991, 80, 6; 781-792
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Curie Temperature and Density of States at the Fermi Level for Al-Cu-Fe Phases: β-Solid State Solution-Approximants-Icosahedral Quasicrystals
Autorzy:
Shalaeva, E.
Prekul, A.
Shchegolikhina, N.
Medvedeva, N.
Powiązania:
https://bibliotekanauki.pl/articles/1373475.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
71.23.Ft
71.20.-b
61.66.Dk
Opis:
A consistent reduction in the absolute value of the negative paramagnetic Curie temperature was found in a series of Al-Cu-Fe phases: β(CsCl)-solid state solution, noncanonical approximant (η-AlCu(Fe) phase), rational approximants (P1+P2-pentagonal phases) and icosahedral quasicrystal. For these Al-Cu-Fe phases, the decrease in the Curie temperature correlates with a reduction of the density of states at the Fermi level which was estimated from the low-temperature heat capacity measurements and first-principles calculations. The observed correlation was related to the antiferromagnetic indirect exchange interaction (Ruderman-Kittel-Kasuya-Yosida interaction) between the localized magnetic moments on Fe induced by the intrinsic structural defects in the Al-Cu-Fe phases. The weakening of Fe 3d-Al s, p hybridization owing to the intrinsic structural defects such as vacancies, antisite defects and distortions of coordination polyhedrons is suggested to be the main mechanism of appearance of localized magnetic moments on Fe atoms.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 572-576
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
d-Wave Superconductivity in a System with Open Boundary Conditions
Autorzy:
Pisarski, P.
Harań, G.
Powiązania:
https://bibliotekanauki.pl/articles/2041464.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Rp
74.72.-h
74.78.Na
74.81.-g
Opis:
We discuss the d-wave superconductivity in confined geometry by imposing open boundary conditions on the attractive Hubbard model. Within the Bogoliubov-de Gennes approach we evaluate the order parameter and charge density distribution in the system.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 721-725
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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