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Wyszukujesz frazę "82.70.Gg" wg kryterium: Temat


Tytuł:
Sol-Gel Derived Lanthanide-Substituted Layered Double Hydroxides $Mg_3//Al_{1-x}Ln_{x}$
Autorzy:
Smalenskaite, A.
Şen, S.
Salak, A.
Ferreira, M.
Beganskiene, A.
Kareiva, A.
Powiązania:
https://bibliotekanauki.pl/articles/1398236.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
82.70.Gg
82.33.Ln
71.20.Eh
78.55.Hx
Opis:
Mg/Al/Ln (Ln = Nd, Sm, Eu) layered double hydroxides (LDHs) were synthesized using sol-gel method for the first time to the best our knowledge. The obtained materials were characterized by X-ray diffraction analysis and fluorescence spectroscopy. The phase composition and luminescent properties of these LDHs were investigated and discussed. The Ln³⁺ substitution effects were investigated in the $Mg_3Al_{1-x}Ln_{x}$ LDHs by changing the Ln³⁺ concentration in the metal cation layers up to 10 mol%. It was demonstrated that only $Mg_3Al_{1-x}Eu_{x}$ LDHs showed luminescence properties, however, no any light emission was observed for the $Mg_3Al_{1-x}Nd_{x}$ and $Mg_3Al_{1-x}Sm_{x}$ LDH samples.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 884-886
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new approach to the presentation of the positron annihilation lifetime spectroscopy results, n-alkanes
Autorzy:
Zgardzińska, B.
Standzikowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1057935.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
78.70.Bj
82.30.Gg
Opis:
The standard form of the positron annihilation lifetime spectroscopy results presentation are two plots of o-Ps lifetime and intensity as a function of external factor, e.g. temperature, pressure. Both o-Ps parameters change (stepwise) when in the medium phase transitions occur. For a more complete picture of the structural changes occurring in the matter we suggest to use an additional plot, in the coordinates, (τ₃, I₃). The hydrocarbons are selected to show the advantages following from the presentation of the results in the intensity-lifetime (INTI) plot.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1496-1500
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemical Information of Chitosan-Based Complex Extracted from Coincidence Doppler Broadening Spectra
Autorzy:
Cao, Xingzhong
Xia, Rui
Yang, Jing
Zeng, Minfeng
Wang, Baoyi
Yu, Runsheng
Wei, Long
Powiązania:
https://bibliotekanauki.pl/articles/1033908.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
64.70.km
82.30.Gg
Opis:
In recent years, coincidence Doppler broadening (CDB) of annihilation radiation measurement on polymeric system has been attracting special attention because of its unique elemental sensitivities in comparison to the traditional Doppler broadening measurement. In the present study, chitosan-Fe₃O₄ nanocomposite (CS-Fe₃O₄) and copper-chitosan (Cu-CS) complexes were prepared through a simple casting method from aqueous solution. The inclusion of Fe₃O₄ nanoparticles in the chitosan matrix is confirmed by X-ray diffraction. In order to obtain data about atomic composition of the annihilation site in the CS composites, CDB measurements were carried out. The normalized CDB ratio curve, which is related to the ratio between the momentum density distribution for the studied samples and pure CS, was displayed to illustrate the variation of ion cores of different elements present in the chitosan matrix. Our result confirms a contribution of active group available in chitosan molecules to the features in the high-momentum region of the CDB ratio curve. The findings show that the local chemical environment of the annihilation site in chitosan-based complexes could be estimated by such positron annihilation spectroscopic investigation.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1535-1537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation Lifetime Analysis of Left- and Right-Handed Alanine Single Crystals
Autorzy:
Eren, B.
Wu, F.
Eren, E.
Jean, Y.
Van Horn, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030024.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
82.30.Gg
34.80.-i
87.15.B-
Opis:
Studies of the interaction of polarized light or particles (including electrons, e¯, or positrons, e⁺) with asymmetric forms of matter has been of interest to scientists since the discovery of chirality and the subsequent development of particle physics. Researchers have been interested in e⁺ interactions with chiral molecules for decades, but with mixed and indecisive results. After reviewing the field, we speculated that the e⁺ or positronium (Ps) might interact differently with chiral pairs of large single crystals, i.e., the left-handed or right-handed asymmetric forms of the crystals - and subsequently observed significant differences in "free positron" annihilation and intensities in the evaluation of left-handed or right-handed quartz single crystals. This result may be understood to be a "particle stereorecognition" phenomenon. To extend this line of inquiry we crystallized mm scale L- or D-alanine crystals and performed positron annihilation lifetime spectroscopy measurements using a ²²Na positron source. Alanine crystals were obtained via slow evaporation of water in a Dewar, or from water/acetone solvent in a temperature-controlled environment. These methods resulted in small ( ≈0.5 cm/side) or large ( ≥1.0 cm/side) crystals, respectively. While some intensity (I₂) results from left-handed and right-handed crystals varied in positron annihilation lifetime spectroscopy analysis, the errors associated with the measurements do not indicate a stereorecognition of alanine via positron interactions.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1456-1460
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positronium Formation in Organic Liquids
Autorzy:
Karbowski, A.
Fedus, K.
Służewski, K.
Bruzdowska, J.
Karwasz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1030028.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
82.30.Gg
36.10.Dr
Opis:
This paper reports on the results of positron annihilation lifetime measurements of three organic liquids: benzene (C₆H₆), cyclohexane (C₆H₁₂), and methanol (CH₃OH). The lifetime spectra are acquired at different temperatures for non-degassed, degassed, and oxygen-saturated samples, at temperatures between 5°C and 25°C. The spectra are analyzed using a standard three-exponential model. The influence of oxygen on each lifetime and intensity component is discussed.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1466-1469
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
IR and Raman Investigation of Some Poly(acrylic) Acid Gels in Aqueous and Neutralized State
Autorzy:
Todica, M.
Stefan, R.
Pop, C.
Olar, L.
Powiązania:
https://bibliotekanauki.pl/articles/1402342.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Dd
82.70.Gg
82.70.Kj
Opis:
The modification of local polymeric conformation of poly(acrylic) acid (PAA), induced by hydration and neutralization with triethanol amine (TEA), was investigated by IR and Raman spectroscopy. The effect of water is the perturbation of hydrogen bonds established between different polymeric chains and the modification of the local conformation of the polymer. The neutralization with TEA affects the carboxylic groups and modifies the local conformation of the polymer. These modifications are correlated with the shift and the modification of the characteristics of IR and Raman spectra.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 128-135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Magnetic Field on the Fluctuations of Charged Oscillators in Viscoelastic Fluids
Autorzy:
Lisý, V.
Tóthová, J.
Powiązania:
https://bibliotekanauki.pl/articles/1202353.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.Jc
05.10.Gg
75.47.-m
82.70.Dd
Opis:
In the present work the generalized Langevin equation is solved for the motion of a charged Brownian oscillator in a magnetic field, when the thermal random force is exponentially correlated in the time. This model is consistent with the assumption that the medium has weakly viscoelastic properties. The velocity autocorrelation function, time-dependent diffusion coefficient and mean square displacement of the particle have been calculated. Our solutions generalize the previous results from the literature and are obtained in a way applicable to other problems of the Brownian motion with memory.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 413-414
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positrons and Positronium Atoms in a Condensed Phase Close to Its Melting Point
Autorzy:
Stepanov, S.
Zvezhinskiy, D.
Byakov, V.
Duplâtre, G.
Stepanov, P.
Powiązania:
https://bibliotekanauki.pl/articles/1196038.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
34.80.Lx
78.70.Bj
82.30.Gg
Opis:
Investigation of the local heating effect at the terminal part of a fast positron track sheds light on the accumulation of defects in a frozen medium close to its melting point. Estimations of the formation energies of the structural defects which may trap the Ps atom as well as a contribution of these defects to the enthalpy of fusion are obtained.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 691-695
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Evidence of Quasi-Free Positronium State in GiPS-AMOC Spectra of Glycerol
Autorzy:
Zvezhinskiy, D.
Butterling, M.
Wagner, A.
Krause-Rehberg, R.
Stepanov, S.
Powiązania:
https://bibliotekanauki.pl/articles/1196485.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
82.30.Gg
34.80.-i
34.80.Lx
Opis:
We present the results of processing of age-momentum correlation spectra that were measured for glycerol by the gamma-induced positron spectroscopy facility. Our research has shown that the shape of experimental s(t) curve cannot be explained without introduction of the intermediate state of positronium (Ps), called quasi-free Ps. This state yields the wide Doppler line near zero lifetimes. We discuss the possible properties of this intermediate Ps state from the viewpoint of developed model. The amount of annihilation events produced by quasi-free Ps is estimated to be less than 5% of total annihilations. In the proposed model, quasi-free Ps serves as a precursor for trapped Ps of para- and ortho-states.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 821-824
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Dynamics of Magnetic Iron Nanoparticles Aggregates in Protein Gels
Autorzy:
Konik, K.
Fornal, P.
Okła, D.
Stanek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1490101.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Jn
83.60.Np
61.25.H-
82.70.Gg
Opis:
The 60 nm metallic iron nanoparticles and its aggregates in gelatine gel were studied by means of optical microscopy, X-ray microtomography, atomic force scanning microscopy and the Mössbauer spectroscopy. The isolated nanoparticles in gel exhibit fast bounded diffusion described by Brownian movement. In the external magnetic field these magnetic particles form spectacular linear aggregates whose local dynamical and magnetic properties were determined from the Mössbauer spectra.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 457-463
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for Preliminary Analysis of Viscosity Behaviour of Some Aqueous Poly(ethylene oxide) Gels
Autorzy:
Todica, M.
Pop, C.
Udrescu, L.
Pop, M.
Powiązania:
https://bibliotekanauki.pl/articles/1505153.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Dd
82.70.Gg
82.70.Kj
Opis:
The dependence of the viscosity on temperature and shear rate was observed for some poly(ethylene oxide) gels with different polymeric concentrations. An algorithm of analysis of experimental data, based on the Arrhenius and power law models, and a mathematical function describing the dependence of the viscosity on temperature and shear rate are proposed.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 880-884
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminum-Doped Zinc Oxide Thin Films Prepared by Sol-Gel and~RF Magnetron Sputtering
Autorzy:
Wu, G.
Chen, Y.
Lu, H.
Powiązania:
https://bibliotekanauki.pl/articles/1504062.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Cd
82.70.Gg
77.55.hf
Opis:
Zinc oxide (ZnO) thin films have become technologically important materials due to their wide range of electrical and optical properties. The characteristics can be further adjusted by adequate doping processes. In this paper, aluminum-doped zinc oxide thin films have been prepared on glass substrates using a sol-gel route and the radio-frequency magnetron sputtering process. The stoichiometry could be easily adjusted by controlling the nanosized precursor concentration and the thickness by dip-coating cycles. On the other hand, the mixed $N_2O//Ar$ plasma gas provided adequate N doping for the RF sputtering process. The results showed the low electrical resistivity of 21.5 Ω cm with the carrier concentration of - 3.21 × $10^{18} cm^{-3}$ for the n-type aluminium-doped zinc oxide film. They were 34.2 Ω cm and + 9.68 × $10^{16} cm^{-3}$ for the p-type aluminium-doped zinc oxide film. The optical transmittance has been as high as 85-90% in the 400-900 nm wavelength range. The aluminium-doped zinc oxide (2 at.% Al) films exhibited the hexagonal wurzite structure with (002) preferred crystal orientation. The electrical characteristics were depicted by the gradual increase in N and NO that occupy the oxygen vacancies.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 149-152
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Casimir Force between Nanoparticles Immersed in a Crosslinked Polymer Blend
Autorzy:
El Fassi, S.
Benhamou, M.
Boughou, M.
Kaidi, H.
El Yaznasni, M.
Ridouane, H.
Powiązania:
https://bibliotekanauki.pl/articles/1535673.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.25.Hq
64.75.+g
82.70.Gg
Opis:
We consider a crosslinked polymer blend made of two polymers of different chemical nature. We suppose that such a system incorporates small colloidal particles, which prefer to be attracted by one polymer, close to the spinodal temperature. This is the so-called critical adsorption. As assumption, the particle diameter, $d_0$, is considered to be small enough in comparison with the size of microdomains (mesh size) ξ* ~ $an^{1//2}$, with a - the monomer size and n - the number of monomers between consecutive crosslinks. The critical fluctuations of the crosslinked polymer mixture induce a pair-potential between particles located in the non-preferred phase. The purpose is the determination of the Casimir pair-potential, $U_2 (r)$, as a function of the interparticle distance r. To achieve calculations, use is made of an extended de Gennes field theory that takes into account the colloid-polymer interactions. Within the framework of this theory, we first show that the pair-particle is attractive. Second, we find for this potential the exact form: $U_2(r)//k_{B}T = - A_{H}(d_0//r)^2 exp(-r//ξ*) - B_{H}(d_0//r)^4 exp(-2r//ξ*)$, with the known universal amplitudes $A_{H}$ > 0 and $B_{H}$ > 0 (the Hamaker constants). This expression clearly shows that the pair-potential differs from its homologue with no crosslinks only by the two exponential factors exp(-r/ξ*) and exp(-2r/ξ*). The main conclusion is that the presence of reticulations reduces substantially the Casimir effect in crosslinked polymer blends.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 606-612
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrodynamic Memory in the Motion of Charged Brownian Particles across the Magnetic Field
Autorzy:
Tóthová, J.
Lisý, V.
Powiązania:
https://bibliotekanauki.pl/articles/1535477.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.Jc
05.10.Gg
75.47.-m
82.70.Dd
Opis:
An exact solution of the Langevin equation is given for a charged Brownian particle driven in an incompressible fluid by the magnetic field, taking into account the hydrodynamic aftereffect. The stochastic integro-differential Langevin equation is converted to a deterministic equation for the particle mean square displacement. We have found the mean square displacement and other time correlation functions describing the particle motion. For the motion along the field the known results from the theory of the hydrodynamic motion of a free Brownian particle are recovered. The correlation functions across the field contain at long times the familiar Einstein terms and additional algebraic tails. The longest-lived tail in the mean square displacement is proportional to $t^{1//2}$. At short times the motion is ballistic and independent of the magnetic field.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1051-1053
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free-Volume Studies in Polycaprolactone/Poly(propylene oxide) Urethane/Urea Membranes by Positron Lifetime Spectroscopy
Autorzy:
Ferreira Marques, M.
Gordo, P.
de Lima, A.
Queiroz, D.
Norberta de Pinho, M.
Major, P.
Kajcsos, Zs.
Powiązania:
https://bibliotekanauki.pl/articles/1812490.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
78.70.Bj
82.30.Gg
Opis:
Positron annihilation lifetime spectroscopy was used to study the free volume parameters in polypropylene oxide-based tri-isocyanate terminated prepolymer/polycaprolactone diol bi-soft urethane/urea membranes (PU/PCL) with PCL content from 5 up to 25 wt%. Positron annihilation lifetime spectroscopy measurements carried out in the temperature range 298-324 K mirrored the phase separation of the various soft and hard segments present in the membranes. The size and amount of free volume holes determined by positron annihilation lifetime spectroscopy appear to be correlated with the $CO_2$ gas permeability through the membranes.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1359-1364
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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