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Wyszukujesz frazę "78.70.-g" wg kryterium: Temat


Tytuł:
Magnetron Sputtered SnO$\text{}_{x}$ Films on Tin Probed by Slow Positron Implantation Spectroscopy
Autorzy:
Nancheva, N.
Docheva, P.
Anwand, W.
Brauer, G.
Coleman, P. G.
Powiązania:
https://bibliotekanauki.pl/articles/2008107.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.-g
Opis:
SnO$\text{}_{x}$ films grown on tin substrates via d.c. magnetron sputtering at different bias were studied by slow positron implantation spectroscopy. The change of substrate bias from -40 V to -140 V and its influence on the films is shown and discussed.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 623-626
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Implantation Profile in Kapton
Autorzy:
Dryzek, J.
Dryzek, E.
Powiązania:
https://bibliotekanauki.pl/articles/2047124.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.-g
Opis:
The discussion presented in the paper focuses on processes accompanying positron implantation in condensed matter. They finally constitute the positron implantation profile which generally does not exhibit the exponential behavior as it is concluded from the Monte Carlo simulation made using the EGSnrc 4.0 code. The simulation was performed for the kapton and two commonly used positron sources $\text{}^{22}$Na and $\text{}^{68}$Ge/g$\text{}^{68}$Ga. New formula for the implantation profile was proposed.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 577-582
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemical Effects on the K$\text{}_{β}$/K$\text{}_{α}$ Intensity Ratios in First-Row Transition Element Compounds
Autorzy:
Küçükönder, A.
Büyükkasap, E.
Yilmaz, R.
Şahin, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1994736.pdf
Data publikacji:
1999-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.-g
82.80.-d
Opis:
Chemical Effects on the K$\text{}_{β}$/K$\text{}_{α}$ X-ray Intensity Ratios for Some First-row Transition Element Compounds Were Studied Experimentally and Calculated. the Vacancies in the K Shell Were Created by 59.5 keV γ rays from an $\text{}^{241}$Am Radioactive Source and Characteristic X-ray Radiation from Sample Was Measured by Using Si(li) and Ge(li) Detectors. the Calculations Were Carried Out Using Brunner's Model. the Calculated Relative K$\text{}_{β}$/K$\text{}_{α}$ X-ray Intensity Ratios Are in Good Agreement with the Present and the Previously Published Experimental Data.
Źródło:
Acta Physica Polonica A; 1999, 95, 2; 243-250
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Temperature and Pressure Dependence of the Free Volume in Fluoroelastomers from PALS and PVT Experiments
Autorzy:
Dlubek, G.
Sen Gupta, A.
Wawryszczuk, J.
Kilburn, D.
Pionteck, J.
Krause-Rehberg, R.
Goworek, T.
Alam, M. A.
Kaspar, H.
Lochhaas, K. H.
Powiązania:
https://bibliotekanauki.pl/articles/2042202.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
78.70.-g
Opis:
Positron lifetime and pressure-volume-temperature experiments were performed as function of T (100-485 K) and P (10$\text{}^{-5}$ Pa-500 MPa) on a fluoroelastomer. From positron annihilation lifetime spectroscopy, analyzed with LT9.0 assuming a dispersion in the e$\text{}^{+}$ (τ$\text{}_{2}$) and o-Ps (τ$\text{}_{3}$) lifetime, the mean, 〈v$\text{}_{h}$〉, and the width (standard deviation), σ$\text{}_{h}$, of the hole size distribution were calculated. The pressure-volume-temperature data were analyzed using the Simha-Somcynsky hole-lattice theory to estimate the specific hole free volume V$\text{}_{f}$. From a comparison of V$\text{}_{f}$ with 〈v$\text{}_{h}$〉 the specific hole number, N'$\text{}_{h}$, is estimated. The data from thermal expansion and pressure experiments show complete agreement when taking into account the compressibility of the occupied volume.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 685-689
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simplified Method for the Estimation of Hole Free Volume Fraction from the Specific Volume
Autorzy:
Dlubek, G.
Pionteck, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812487.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
78.70.-g
Opis:
A brief introduction in the equation of state of the Simha-Somcynsky hole theory is presented. This theory allows to calculate the volume fraction h of free volume holes from pressure-volume-temperature experiments. These holes are detected by ortho-positronium and from the value of h and the mean ortho-positronium hole size the hole density may be calculated. We discuss a simplified method to estimate h which makes use of the relation V* = 1.52 $V_W$ between the scaling volume V* of the Simha-Somcynsky hole theory equation of state and the van der Waals volume $V_W$. Moreover, we present a new simplified method for the estimation of h which starts with the Schottky (Arrhenius) equation for the concentration of thermal vacancies and makes use of a linear relation between the scaling temperature T* and the hole formation enthalpy $H_h$, $H_h$(kJ/mol)=6.54×$10^{-4}$T*(K).
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1331-1338
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Partial Probabilities of X-Ray Bremsstrahlung Transitions
Autorzy:
Nietubyć, R.
Sobczak, E.
S̆imůnek, A.
Vackár̆, J.
S̆ipr, O.
Powiązania:
https://bibliotekanauki.pl/articles/1963394.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.Kz
78.70.-g
Opis:
High-energy electrons bombarding a solid produce X-ray bremsstrahlung radiation, which is one of few elementary processes occurring during electron-solid interactions. Photon emission results from electron transition to an unoccupied electron state above the Fermi level. In this work matrix elements of X-ray bremsstrahlung transitions were calculated for solids containing elements from N (Z=7) to Pd (Z=46) and photon energies 1487 eV and 5415 eV. It was found that in the case of light elements the X-ray bremsstrahlung transitions to s-type final states dominate over all other symmetries. It was also shown that X-ray bremsstrahlung transition probabilities increase with decreasing photon energy and increasing atomic number Z. Dependence of X-ray bremsstrahlung transition probabilities on the electron final state energy is also presented in this work.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 841-846
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Beam Induced Modification of Polymer-Like Carbon Coatings
Autorzy:
Plaipaitė-Nalivaiko, R.
Adlienė, D.
Adlys, G.
Powiązania:
https://bibliotekanauki.pl/articles/1400455.pdf
Data publikacji:
2013-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.-g
78.66.-w
78.30.-j
Opis:
Carbon coatings can possess diamond-like, polymer-like, graphite-like or other properties depending on deposition methods and technological parameters. Structural changes in the polymer-like carbon coatings irradiated by high energy electrons are discussed in the present paper. The polymer-like carbon coatings have been synthesized from $C_2H_2$ gas in the radio frequency dual-plasma reactor using various deposition parameters. Plasma enhancement chemical vapor deposition deposited experimental polymer-like carbon samples were irradiated with high energy electrons in the medical linear accelerator. The investigations of carbon coatings have been carried out using the Fourier-transform infrared, Raman and UV-VIS spectroscopies. Modification of the polymer-like carbon coatings is discussed in relation with radiation induced formation of free radicals and unsaturated bonds along with possible cross-linking processes.
Źródło:
Acta Physica Polonica A; 2013, 123, 5; 871-873
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relations Between Hole Volume and Macroscopic Volume in Various Polymers
Autorzy:
Dlubek, G.
Alam, M. A.
Saarinen, K.
Stejny, J.
Fretwell, H. M.
Powiązania:
https://bibliotekanauki.pl/articles/2007964.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
65.70.+y
78.70.-g
Opis:
Different definitions of the free volumes are discussed and related to the total specific volume and to the local free (hole) volume. Positron lifetime measurements are reported for polyethylene, polytetrafluoroethylene, and CR39-copolymers. Two long-lived components appear in polyethylene and polytetrafluoroethylene, which were attributed to o-Ps annihilations in crystalline regions and in holes of the amorphous phase. From a relation between the coefficients of the thermal expansion of macroscopic and hole volume, the fractional hole volume h and from this the number of holes, N, is estimated. Values of T$\text{}_{g}$=195 K, h$\text{}_{g}$=4.5% (polyethylene) and 5.7% (polytetrafluoroethylene) and N$\text{}_{g}$=0.73 nm$\text{}^{-3}$ (polyethylene) and 0.36 nm$\text{}^{-3}$ (polytetrafluoroethylene) were obtained. In semicrystalline polymers these values agree with estimates obtained from the densities of the crystalline and amorphous phases. The effect of cross-linking on the free-volume properties of CR39-copolymer networks was studied. The comparison of the hole volume with the specific volume allowed us to estimate the number density of holes to ≈1 nm$\text{}^{-3}$.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 521-526
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental Gamma Dose Evaluation During Explosive Materials Analysis by PGNAA Technique Using MCNPX Code
Autorzy:
Nasrabadi, M.
Omidi, S.
Powiązania:
https://bibliotekanauki.pl/articles/1401224.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.52.-g
61.80.-x
78.70.-g
Opis:
Increased use of radiation in medicine, industry, and laboratories, requires safe conditions to be provided for its optimal use. One of the cases in which people are exposed to radiation, is during the detection of explosive materials by PGNAA method. Therefore, external dosimetry is necessary for workplaces where the method is used. In this study, Monte Carlo simulation program, MCNPX has been used to simulate gamma dose in the environment during the detection of explosive materials by PGNAA method. The simulated results were validated practically. The results indicate a good agreement between the simulated and measured data. The study demonstrated that MCNPX code can be used effectively for simulating gamma dose in various environments.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 961-964
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of Radiation Sensitivity of the Oxygen-Containing Fluorite Crystals
Autorzy:
Kachan, S.
Salapak, V.
Nahurskiy, O.
Pirko, I.
Powiązania:
https://bibliotekanauki.pl/articles/1030896.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.-x
78.47.-p
78.70.-g
Opis:
The parameters of radiation sensitivity of the oxygen-doped fluorite crystals were calculated in a one-dimensional model. The limit concentrations of the color centers as a function of the concentration of the oxygen impurity in the fluorite crystal were defined. Fluorite crystals with anti-Frenkel defects in the anion sublattice of the crystal have a specific property: the discolored after irradiation crystal being irradiated repeatedly with ionizing radiation retains the "memory" of the preceding irradiation. Using an ion chain model this paper studies under what conditions the "radiation memory" effect can arise in the MeF₂-O²¯ crystals as well as the extent of its contribution into the overall radiation sensitivity of the crystal.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 824-828
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation Defects in $CaF_2-CaO$ Crystals
Autorzy:
Kachan, S.
Obukhova, E.
Shtanko, V.
Chinkov, E.
Powiązania:
https://bibliotekanauki.pl/articles/1550546.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.-x
78.47.-p
78.70.-g
Opis:
The spectral and kinetic parameters of electron-pulse-initiated transient absorption of oxygen-doped $CaF_{2}$ crystals were studied using pulsed spectrometry with a nanosecond time resolution. It is shown that the formation of a $M_{A}^{+}$ color centers in $CaF_{2}$-0.01M%CaO crystals occurs by thermally activated diffusion of the vacancies. Activation energy of $M_{A}^{+}$ color centers formation process of 0.4 eV is established.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 195-198
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Resistivity and Positron Lifetime Studies of Precipitation Effects in Al-Cu Alloy
Autorzy:
Αda, P.
Cieslar, M.
Vostrý, P.
Bečvář, F.
Νovotný, I.
Procházka, I.
Powiązania:
https://bibliotekanauki.pl/articles/1933483.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
78.70.-g
81.40.-z
Opis:
Decomposition of the supersaturated solid solution of 2 at.% Cu in Al was investigated by means of electrical resistivity and high-resolution positron lifetime measurements. The phase composition of this alloy was determined by transmission electron microscopy. Electrical resistivity measurements were performed by a classical four-point method. Positron lifetime spectra were measured by means of a spectrometer consisting of two BaF$\text{}_{2}$ detectors and a standard fast-slow coincidence system. The specimens were first exposed to the solution heat treatment at 783 K for 19 hours with a subsequent quenching. Then the specimens were isochronally annealed in the temperature range 293 ÷ 573 K. Annealing responses of electrical resistivity and positron annihilation were studied. Resistivity measurements as well as transmission electron microscopy observations confirmed the well-known decomposition sequence of the Al-Cu alloy. The decomposition of the alloy was manifested by the decrease in the intensity of positron lifetime component τ$\text{}_{2}$ = (207 ±2 ) ps correlated with simultaneous appearance and increase in the intensity of τ$\text{}_{3}$ = (180 ± 5) ps component. Component τ$\text{}_{2}$ originates from positron annihilation in vacancies trapped at the Guinier-Preston zones while τ$\text{}_{3}$ comes from annihilation of the positrons localized in the misfit dislocations at coherent precipitates of the Al$\text{}_{2}$Cu phase. The shortest observed component τ$\text{}_{1}$ apparently belongs to annihilation of untrapped positrons.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 111-117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-Ray Magnetic Scattering
Autorzy:
Cooper, M.
Powiązania:
https://bibliotekanauki.pl/articles/1920839.pdf
Data publikacji:
1992-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Dp
75.50.-y
78.70.-g
78.70.Ck
Opis:
Magnetic X-ray diffraction with synchrotron radiation is now an established technique for studies of antiferromagnets. The problems associated with the small magnetic scattering cross-section being alleviated by the dramatic enhancements found near absorption edges through resonant exchange scattering. The technique is particularly useful for those materials that require high wavevector resolution to reveal the structural phase transitions that accompany the magnetic ordering process or those that are difficult to investigate with neutrons, (e.g. samarium, for which recent results are presented). In the actinides the work is also motivated by the objective of performing an empirical separation of the spin and orbital components of magnetisation. Diffraction studies of ferromagnets require circular polarised radiation and suffer from the superposition of the small magnetic signal and the charge scattering; to date Laue methods have proved more successful than monochromatic beam studies. Ferro- and ferrimagnets can also be studied by Compton (inelastic) scattering but the cross-section is less well established: considerable effort has been directed to determining whether orbital magnetisation can be measured in these experiments and results on HoFe$\text{}_{2}$ now indicate this is not so. Magnetic Compton profiles provide information about the momentum distribution of electrons with unpaired spins, and this, together with magnetisation data can provide the basis for the separation of spin and orbital magnetisation.
Źródło:
Acta Physica Polonica A; 1992, 82, 1; 137-146
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:
Temperature Dependent Variations of Properties of Polymer-Like Carbon Coatings Treated with High Energy Electrons
Autorzy:
Plaipaitė-Nalivaiko, R.
Vigricaitė, L.
Adlienė, D.
Rutkūnienė, Ž.
Powiązania:
https://bibliotekanauki.pl/articles/1402232.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Fe
68.37.Ps
78.30.Jw
78.70.-g
Opis:
Polymer-like carbon coatings can be used for the protection of micro-electromechanical devices functioning in chemically or radiation harsh environment due to their beneficial properties. Properties of carbon coatings depend on the method of synthesis, initial gas mixture, admixture of additives, temperature and other technological parameters. Modification of carbon structures is possible applying high energy electrons. Coating mechanical properties become almost stable after their pretreatment with some doses of high energy electrons. Polymer-like carbon coatings were synthesized from acetylene gas plasma on n-type silicon substrates in the RF plasmotron system at temperatures in the range 293-673 K using plasma enhanced chemical vapor deposition method. Series of samples were prepared and irradiated with high energy (6 MeV) electrons in a medical linear accelerator. The ellipsometric method was used for estimation of some optical parameters and thickness of synthesized coatings. Structural changes of polymer-like carbon coatings were evaluated using the Raman spectroscopy and surface morphology was assessed by atomic force microscopy. Electron beam induced structural changes in the coatings were analyzed using the obtained results. The relations between the synthesis temperature and samples structure and surface morphology are discussed.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 915-917
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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