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Wyszukujesz frazę "76.60.-k" wg kryterium: Temat


Tytuł:
Tuned Probehead for NMR Spectroscopy in Magnetically Ordered Materials
Autorzy:
Sedlák, B.
Kouřil, K.
Chlan, V.
Řezníček, R.
Křišťan, P.
Pfeffer, M.
Englich, J.
Štěpánková, H.
Powiązania:
https://bibliotekanauki.pl/articles/1534619.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Pt
76.60.-k
76.60.Lz
Opis:
This work describes the design of a tuned NMR probehead that was developed for measurement of very broad spectra in fully impedance matched mode. The probehead is constructed as an insert of continuous flow cryostat to allow operation down to helium temperatures. Properties of the probehead are demonstrated on $\text{}^{57}Fe$ NMR in magnetic oxide with spinel structure.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 924-925
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Free Volume of Condensed Phases Confined in a Nanopore as Seen by Computer Simulations and Compared to PALS
Autorzy:
Račko, D.
Powiązania:
https://bibliotekanauki.pl/articles/1196175.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.20.Ja
76.60.-k
64.70.pm
Opis:
In this contribution the free volume of glycerol phase confined in a nanopore in a wide temperature range is computed. The computed free volume is compared to the previously computed values in the glycerol bulk. The mean cavity volumes are also discussed with the experimental measurements by positronium annihilation lifetime spectroscopy. The computer simulations show that in the case of the confined glycerol phase the mean cavity volumes are larger than in the simulated bulk, and also the temperature dependence has a different qualitative behavior; the computed data are in agreement with experimental measurements performed for glycerol in a pore of comparable size with diameter 6 nm. The simulations also indicate that an aspect of filling a pore is important for experimentalists. In the case of a perfectly sealed pore the cavity volume is observed to rise with decreasing temperature.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 785-788
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SWR Studies of Higher-Order Surface Anisotropy Terms in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Diep, H.
Powiązania:
https://bibliotekanauki.pl/articles/1030424.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
76.60.-k
Opis:
We extend the theory of spin-wave resonance (SWR) by introducing a new formula representing the surface pinning parameter as a series of contributions from different anisotropies existing in (Ga,Mn)As thin films. Comparing our theory with the reported experimental studies of SWR in thin films of the ferromagnetic semiconductor (Ga,Mn)As, we find that besides the first-order cubic anisotropy, higher-order cubic anisotropies (in the second and third orders) as well as uniaxial anisotropies (perpendicular in the first and second orders, and in-plane diagonal) occur on the surface of this material. To our best knowledge this is the first report of the existence of higher-order surface anisotropy fields in (Ga,Mn)As thin films.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 635-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of Iron Oxide Nanoparticles Studied by $\text{}^{57}Fe$ NMR
Autorzy:
Křišťan, P.
Chlan, V.
Štěpánková, H.
Řezníček, R.
Görnert, P.
Payer, P.
Powiązania:
https://bibliotekanauki.pl/articles/1378149.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
75.50.Gg
75.50.Tt
Opis:
In this work we apply nuclear magnetic resonance (NMR) spectroscopy of $\text{}^{57}Fe$ nuclei for investigation of submicron and nanocrystalline iron oxide systems. The studied iron oxide particles are obtained from ferrous hydroxide gels (prepared from $FeCl_{2}$ and KOH) by aging at elevated temperatures (90 °C) with $KNO_{3}$ as oxidant. The $\text{}^{57}Fe$ NMR spectra of the samples are measured in temperature range 4.2-370 K in a zero external magnetic field. Signals of $\text{}^{57}Fe$ nuclei assigned to tetrahedral and octahedral iron sites are well resolved. The NMR spectra and their temperature dependences are compared with those of stoichiometric and nonstoichiometric magnetite single crystals, as well as with samples of maghemite.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 138-139
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid State ¹³C Nuclear Magnetic Resonance Study of Morphology and Molecular Mobility in Quenched Poly(3-hydroxybutyrate)
Autorzy:
Baran, A.
Vrábel, P.
Olčák, D.
Powiązania:
https://bibliotekanauki.pl/articles/1032243.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
81.05.Lg
76.60.-k
74.25.nj
Opis:
Single pulse magic angle spinning ¹³C NMR spectra and the carbon spin-lattice relaxation times T₁(¹³C) were used for the study of morphology and molecular mobility in poly(3-hydroxybutyrate) quenched in cold water after melting in a twin-screw extruder. The crystallinity of the quenched sample was found to be comparable with that of virgin material, and the decrease in dimensions of the crystallites grown after quenching was deduced from the single pulse magic angle spinning ¹³C NMR spectra. The spin-lattice relaxation curves for the carbons of the CO, CH, CH₂ and CH₃ groups were found to be bi-exponential, which enables the molecular mobility within crystalline and amorphous domains to be studied. The spin-lattice relaxation times T₁(¹³C) estimated for the carbons of the CO, CH, CH₂ groups show the chain mobility enhancement within crystalline domains of the quenched sample, but the influence of the quenching on the CH₃ group rotation and on the main chain motion within amorphous regions was not observed.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1144-1146
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid State $\text{}^{13}C$ NMR Study of Modified Polyhydroxybutyrate
Autorzy:
Vrábel, P.
Hronský, V.
Fričová, O.
Koval'aková, M.
Chodák, I.
Alexy, P.
Powiązania:
https://bibliotekanauki.pl/articles/1382700.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
76.60.-k
81.05.Lg
Opis:
Structural changes in polyhydroxybutyrate (PHB) brought about by addition of chain extender and/or plasticizer were studied using $\text{}^{13}C$ MAS NMR spectra, which were measured using the direct polarization technique at 30 and 98°C. Four resonances associated with the CO, CH, $CH_{2}$ and $CH_{3}$ groups of PHB were observed in the spectra. The $CH_{3}$ resonance appearing at 98°C shows splitting into two lines related to the crystalline and amorphous regions. Analysis of the $CH_{3}$ resonances made it possible to estimate the influence of applied modifications on crystallinity and distribution of conformations in amorphous and crystalline domains of PHB samples.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 419-420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relaxation of $\text{}^{53}$Cr Spin Echo Signals in Cd$\text{}_{0.985}$Ag$\text{}_{0.015}$Cr$\text{}_{2}$Se$\text{}_{4}$
Autorzy:
Abelyashev, G. N.
Berzhansky, V. N.
Polulyakh, S. N.
Sergeev, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/2013365.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.20.+q
76.60.-k
76.60.Lz
Opis:
The frequency dependences of the relaxation times of NMR spin echo signals of quadrupole nuclei $\text{}^{53}$Cr at t$\text{}_{e}$=τ and t$\text{}_{e}$=3τ in ferromagnetic semiconductor Cd$\text{}_{0.985}$Ag$\text{}_{0.015}$Cr$\text{}_{2}$Se$\text{}_{4}$ were investigated at temperature 4.2 K. It was shown that there are two kinds of the quadrupole nuclei $\text{}^{53}$Cr, which have quite different relaxation times. The existence of two kinds of the nuclei $\text{}^{53}$Cr was connected with doping of the cadmium selenochromite with Ag$\text{}^{+}$ ions.zap
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 753-756
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasicritical Behaviour of the NMR and µSR Relaxation in YMn$\text{}_{2}$D$\text{}_{x}$
Autorzy:
Paja, A.
Mietniowski, P.
Figiel, H.
Powiązania:
https://bibliotekanauki.pl/articles/2013711.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.-s
76.60.-k
76.75.+i
Opis:
The magnetic and structural properties of YMn$\text{}_{2}$ are strongly influenced by introduction of hydrogen (deuterium) in the structure, however, it only slightly modifies the noncollinear antiferromagnetic structure of the compound. The temperature dependences of the NMR relaxation times T$\text{}_{1}$ and T$\text{}_{2}$ of deuterium and the zero-field relaxation of muons in YMn$\text{}_{2}$D$\text{}_{x}$ were measured at temperatures above the magnetic ordering temperature T$\text{}_{N}$. The corresponding relaxation rates are described by the empirical expression (T/T$\text{}_{N}$-1)$\text{}^{-η}$, where the exponent η increases linearly with deuterium concentration x. To explain this behaviour, the Moriya theory of spin fluctuations was used. The expressions for NMR and μSR relaxation rates have been calculated. The resultant formulae agree well with the experiment, giving reasonable values of fitting parameters. The results obtained are discussed in terms of spin fluctuation excitation spectrum.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 867-870
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proton and Deuteron Relaxation Study of Molecular Dynamics in Lysozyme Solutions
Autorzy:
Kakule, J. F.
Węglarz, W. P.
Shenoy, R. K.
Sharp, A. R.
Peemoeller, H.
Powiązania:
https://bibliotekanauki.pl/articles/2014096.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
87.15.-v
Opis:
A nuclear magnetic resonance spin-lattice relaxation dispersion study of the relaxation of several magnetization components in both natural and deuterated lysozyme solutions was undertaken at 20°C. Proton and deuteron resonances were employed. The two-dimensional time evolution of the magnetization and the spin-spin relaxation were analyzed. In addition, an isotopic dilution study was performed at 5 and 30.6MHz. The results indicate that the water proton spin-lattice relaxation rate which arises from intermolecular relaxation between the water protons and the lysozyme protons represents a relatively strong relaxation mechanism. A model for the dynamics of the water molecules, consistent with the proton and deuteron dispersions as well as with the isotopic dilution results, is presented.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 131-152
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pressure Effect on Yb-Based Strongly Correlated Electron Systems
Autorzy:
Mito, T.
Otani, M.
Nakamura, M.
Koyama, T.
Wada, S.
Kotegawa, H.
Kobayashi, T.
Idzikowski, B.
Reiffers, M.
Sarrao, J.
Powiązania:
https://bibliotekanauki.pl/articles/1810284.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
75.30.Kz
75.30.Mb
76.60.-k
Opis:
We studied pressure effects on $YbCu_5$ and $YbInCu_4$, good examples of the Yb-based compounds to investigate the nonmagnetic-magnetic transition in Yb-based strongly correlated electron systems. With increasing pressure, the low-temperature Fermi liquid state of $YbCu_5$ is gradually suppressed, suggesting the second-order like nonmagnetic-magnetic transition around the pressure of 5-6 GPa. On the other hand, in $YbInCu_4$ which has a pressure-induced magnetic ordered ground state above $P_C$=2.45 GPa, both high-temperature paramagnetic and low-temperature intermediate valence phases are insensitive to pressure. Our results confirm the first-order nature of the transition between the intermediate valence and magnetic ordered phases with pressure.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 47-52
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of Antioxidants Activity using NMR Relaxation Measurements
Autorzy:
Wierzuchowska, D.
Witek, M.
Blicharska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1030645.pdf
Data publikacji:
2018-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
76.90.+d
76.30.Rn
Opis:
Formation of free radicals in biological solutions leads to the changes in water protons relaxation times. Therefore, NMR relaxation measurements were used to investigate kinetics of oxidation processes induced by the addition, in low amounts, of hydrogen peroxide (H_2O_2) to aqueous protein solution and to blood serum. The measured relaxation times were not stable over time because of the progressive formation of free radicals and their damaging action to the protein structure. The addition of antioxidants (ascorbic acid, gallic acid etc.) changed the relaxation time courses due to free radical scavenging. Similar time courses, thus anti-oxidant actions, were observed in various blood serum without antioxidant additive. Moreover, the observed kinetics of spin-lattice relaxation time (T_1) depended on several factors, such as: structure and concentration of protein solutions and activity and concentration of the added antioxidants.
Źródło:
Acta Physica Polonica A; 2018, 133, 2; 289-291
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear Spin Relaxation in Periodically Perturbed Systems IV. The Relaxation in the Presence of Double Rotation and Pulse Sequence
Autorzy:
Blicharski, J. S.
Jasiński, G.
Klose, G.
Powiązania:
https://bibliotekanauki.pl/articles/1931829.pdf
Data publikacji:
1994-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
Opis:
The effective relaxation times are calculated in the weak collision case for the system of identical nuclear spins perturbed by double rotation, periodic sequences of r.f. pulses and spin interactions.
Źródło:
Acta Physica Polonica A; 1994, 86, 6; 1001-1005
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear SPin Relaxation in Periodically Perturbed Systems. III. The Relaxation in the Presence of Double Rotation
Autorzy:
Blicharski, J.
Jasiński, G.
Powiązania:
https://bibliotekanauki.pl/articles/1924283.pdf
Data publikacji:
1992-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
Opis:
The effective spin relaxation times are calculated in the presence of double rotation in the weak collision case.
Źródło:
Acta Physica Polonica A; 1992, 82, 6; 993-997
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear Spin Relaxation in Periodically Perturbed Systems. II. Like and Unlike Spins
Autorzy:
Blicharski, J. S.
Wołak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1920949.pdf
Data publikacji:
1992-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
Opis:
The effective relaxation time T$\text{}_{2e}$ is calculated in the weak collision case for a system consisting of resonant nuclear spins I and nonresonant spins S, perturbed by periodic sequences of r.f. pulses and dipole-dipole interactions.
Źródło:
Acta Physica Polonica A; 1992, 82, 3; 511-515
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear Spin Relaxation in Periodically Perturbed Systems
Autorzy:
Blicharski, J. S.
Wolak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1887459.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
Opis:
The effective relaxation time T$\text{}_{2e}$ is calculated in the weak collision case for a system of identical nuclear spins perturbed by periodic sequences of r.f. pulses and dipole-dipole and quadrupole interactions.
Źródło:
Acta Physica Polonica A; 1991, 79, 4; 591-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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