Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "82.70.Gg" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 24
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:
$\text{}^{1}$H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions
Autorzy:
Dobies, M.
Kuśmia, S.
Jurga, S.
Powiązania:
https://bibliotekanauki.pl/articles/2043388.pdf
Data publikacji:
2005-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Gg
87.15.By
87.15.Rn
82.56.-b
87.15.He
83.10.-y
87.15.La
Opis:
The $\text{}^{1}$H NMR relaxometry in combination with water proton spin-spin relaxation time measurements and rheometry have been applied to study the ionic gelation of 1% w/w aqueous low methoxyl pectin solution induced by divalent Ca$\text{}^{2+}$ cations from a calcium chloride solution. The model-free approach to the analysis of $\text{}^{1}$H NMR relaxometry data has been used to separate the information on the static (β) and dynamic (〈τ$\text{}_{c}$〉) behaviour of the systems tested. The $\text{}^{1}$H NMR results confirm that the average mobility of both water and the pectin molecules is largely dependent on the concentration of the cross-linking agent. The character of this dependency (β,〈τ$\text{}_{c}$〉 and T$\text{}_{2}$ vs. CaCl$\text{}_{2}$ concentration) is consistent with the two-stage gelation process of low methoxyl pectin, in which the formation of strongly linked dimer associations (in the range of 0-2.5 mM CaCl$\text{}_{2}$) is followed by the appearance of weak inter-dimer aggregations (for CaCl$\text{}_{2}$ ≥ 3.5 mM). The presence of the weak gel structure for the sample with 3.5 mM CaCl$\text{}_{2}$ has been confirmed by rheological measurements. Apart from that, the T$\text{}_{1}$ and T$\text{}_{2}$ relaxation times have been found to be highly sensitive to the syneresis phenomenon, which can be useful to monitor the low methoxyl pectin gel network stability.
Źródło:
Acta Physica Polonica A; 2005, 108, 1; 33-46
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:
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:
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
Tytuł:
Change of Free Volume in Polymer Gels As Studied by Positron Annihilation Lifetimes
Autorzy:
Ito, K.
Ujihira, Y.
Yamashita, T.
Horie, K.
Powiązania:
https://bibliotekanauki.pl/articles/2008070.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.70.Gg
Opis:
Variations of a free volume size of a poly(N-isopropylacrylamide) gel and a polyacrylamide gel during a volume phase transition induced by a change of external environment - temperature, solvent composition, pH, and ion strength, are described. The free volume size is probed by positron annihilation lifetime technique. Variations of the free volume size suggest that a nanoscopic environment of the gels is affected by the free volume of the solvent phase and an interaction between the polymer chain and the solvent molecule in the swollen state, and by the aggregation of the polymer chain and a balance of the interaction among the polymer chain and the solvent molecules in the collapsed state. It is revealed that the free volume size reflects the essential change of the nanoscopic environment in the gels which could induce the macroscopic volume phase transition.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 551-556
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractal Structure of C-S-H and Tobermorite Phases
Autorzy:
Janik, J. A.
Kurdowski, W.
Podsiadły, R.
Samseth, J.
Powiązania:
https://bibliotekanauki.pl/articles/2028897.pdf
Data publikacji:
2001-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.12.Ex
82.70.Gg
Opis:
The C-S-H I phase is the main component of the cement paste, which is a near-amorphous, highly porous gel. Due to high porosity of the sample in this phase we can observe a fractal nature of the volume pores distribution, similar to that observed for silica aerogels. The C-S-H I phase is thermodynamically unstable and crystallize to a tobermorite phase, forming crystal aggregates on the surface of the amorphous paste. The mixture of these two phases, formed in this way, have irregular volume and surface structures, both of which may exhibit the fractal nature. To study the fractal nature of the matter the small angle neutron scattering method is frequently used. We present here the results of small angle neutron scattering studies supported by the X-ray diffraction and scanning electron microscope observations of several samples with the common molar C/S ratio equal to 1. Some of the samples were autoclaved during various time periods to accelerate transformation of the C-S-H I phase to tobermorite. We observed the fractal properties of the volume structure of all samples under study. Moreover, we observed also the fractal behaviors of the surfaces of the samples which were autoclaved.
Źródło:
Acta Physica Polonica A; 2001, 100, 4; 529-537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Fractal Aspects of Cement
Autorzy:
Janik, J. A.
Kurdowski, W.
Podsiadły, R.
Samseth, J.
Powiązania:
https://bibliotekanauki.pl/articles/1952755.pdf
Data publikacji:
1996-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.12.Ex
82.70.Gg
Opis:
Small angle neutron scattering can be used to reveal the fractal nature of matter. The problems of fractal aspects of the structure of cement are related to those of fractal aspects of silica aerogels. Natural cement, when mixed with water, transforms after a series of chemical reactions (in a large part) into an amorphous phase called C-S-H. It is believed that the cationic sublattice composed of CaO$\text{}_{6}$ octahedrons constitutes the C-S-H structural basis, to which the SiO$\text{}_{4}$ tetrahedral chains are attached. It is a layer structure in which the cation sublattice determines the way of SiO$\text{}_{4}$ condensation. It is natural to expect that in this way one may obtain a really amorphous substance, since some tetrahedrons may be lacking, which leads to defects. We present here the results of a small angle neutron scattering and X-ray diffraction study of several samples with the pure C-S-H phase for which during the process of chemical synthesis various ratios of molar contents of CaO and SiO$\text{}_{2}$ were used (various C/S ratios). We obtained a gradual change of fractal characteristics with the change of C/S ratio.
Źródło:
Acta Physica Polonica A; 1996, 90, 6; 1179-1184
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:
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:
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:
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:
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:
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:
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
Wyświetlanie 1-15 z 24

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies