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Wyszukujesz frazę "82.70.Gg" wg kryterium: Temat


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:
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:
Application of Coincidence Doppler Broadening Spectroscopy to Hydrocarbons at Different Substance States
Autorzy:
Yu, R.
Suzuki, T.
Ito, Y.
Djourelov, N.
Kondo, K.
Shantarovich, V. P.
Powiązania:
https://bibliotekanauki.pl/articles/2042205.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
82.30.Gg
78.70.Bj
Opis:
Coincidence Doppler broadening spectroscopy was applied to study n-hexane (C$\text{}_{6}$H$\text{}_{14}$), cyclohexane (C$\text{}_{6}$H$\text{}_{12}$) and cyclohexanone (C$\text{}_{6}$H$\text{}_{10}$O), at solid, as well as liquid states. The experiments were performed in parallel with traditional positron annihilation lifetime spectroscopy. Significant positron trapping by oxygen was observed in cyclohexanone; the oxygen effect is stronger in liquid state than in solid one, which can possibly be attributed to positron solvation in polar solution. Coincidence Doppler broadening results for n-hexane and cyclohexane indicate an existence of higher energetic annihilation electrons in Ps-bubble forming liquids than that in solids.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 697-701
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:
Gelation Process of Toluene-Based bis-Urea in Cyclohexane Studied with Magnetic Resonance Imaging
Autorzy:
Tritt-Goc, J.
Boguszyńska, J.
Szwaj, M.
Boutellier, L.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/2043392.pdf
Data publikacji:
2005-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Gg
76.60.Pc
82.56.Lz
82.56.Na
Opis:
Magnetic resonance imaging was used for studies of the gelation and swelling processes of toluene-based bis-urea prepared in a form of cylindrical tablet and immersed in cyclohexane. The processes were investigated with the use of Bruker AVANCE (300 MHz) spectrometer equipped with a micro imaging probe head. The images were taken for cyclohexane protons within the bis-urea gel formed around the sample dry core at different intervals of the immersion. The mobility of the solvent molecules was estimated from the spatially resolved distribution of the spin-spin relaxation time T$\text{}_{2}$ and the spin densitiesρ, calculated on the basis of the images obtained. It was shown that the time-evolution of the thickness of the gel layer can be well described by the power equation with an exponent equal to 0.47 (±0.04), indicating the Fickian nature of the diffusion of cyclohexane molecules.
Źródło:
Acta Physica Polonica A; 2005, 108, 1; 81-87
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydration of Hydroxypropylmethyl Cellulose: Effects of pH and Molecular Mass
Autorzy:
Tritt-Goc, J.
Kowalczuk, J.
Piślewski, N.
Powiązania:
https://bibliotekanauki.pl/articles/2043541.pdf
Data publikacji:
2005-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Gg
76.60.Pc
Opis:
Magnetic resonance imaging was used to study the diffusion of a water solution of hydrochloric acid (HCl) and sodium hydrochloride (NaOH) into hydroxypropylmethyl cellulose matrices. Polymer in the form of a cylinder was hydrated in a water solvent of pH = 2, 7, and 12 at 37ºC and monitored at equal intervals with a 300 MHz Bruker AVANCE. The spatially resolved spin-spin relaxations times and spin densities, along with a change in the dimension of the glass core of the polymer were determined for hydroxypropylmethyl cellulose tablets as a function of hydration times. The data showed the effects of the pH solvent and of the molecular mass of the polymer on the swelling process, spin-spin relaxation time, and diffusion of solvent molecules into hydroxypropylmethyl cellulose matrices. The time dependence of the diffusion front, effective T$\text{}_{2}$, and proton-density ρ analysis clearly indicate a case II diffusion mechanism in the system composed of a water solution of hydrochloric acid (pH = 2) and hydroxypropylmethyl cellulose, whereas in the case of water solutions with pH = 7 and 12 the anomalous and case I diffusion are observed, respectively.
Źródło:
Acta Physica Polonica A; 2005, 108, 1; 197-205
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:
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:
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:
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:
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:
Positron and Positronium Annihilation in Polymers Studied by Age-Momentum Correlation Spectroscopy
Autorzy:
Sato, K.
Murakami, H.
Ito, K.
Hirata, K.
Kobayashi, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1812549.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
82.30.Gg
42.70.jk
Opis:
Positron (e⁺) and positronium (Ps) annihilation processes in polymers are studied by positron age-momentum correlation spectroscopy, which can sensitively probe momentum distributions of e⁺, p-Ps, and o-Ps. For polyether sulfone and ethylene tetrafluoroethylene copolymer belonging to oxygen-containing polymers (O group) and fluorine-containing polymers (F group), respectively, significant effects of positron trapping by polar element are observed. The Doppler profile of o-Ps pick-off annihilation is strongly influenced by F atoms, giving rise to anomalous broadening. The results are discussed together with our previous data of the S-I₃ correlation in order to explore the feasibility of chemical analysis around the free volumes by age-momentum correlation spectroscopy.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1511-1516
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Is a Molecular Adiabatic Approximation Appropriate to Positronic Atoms and Molecules?
Autorzy:
Mohallem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812542.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.-k
36.10.Dr
78.70.Bj
82.30.Gg
Opis:
The adiabatic approximation to positronic atoms and molecules was considered as an option to the computationally unfeasible methods that treat all particles in a common footing, in two different approaches communicated in the 37th PSPA. Here we present further assessment and comparison of the two approaches as a way of evaluating the potential of adiabatic or, as we found preferable, molecular approaches.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1465-1469
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:
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

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