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Tytuł:
The Nonlinear Diffusion Equation Describing Spread of Impurities of High Density
Autorzy:
Janavičius, A. J.
Lūža, G.
Jurgaitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/2038073.pdf
Data publikacji:
2004-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
The nonlinear diffusion equation is derived by taking into account the local variations in the solvent density, within a mechanism of diffusion driven by random particle collisions. Analytical solutions for the case of spherical-symmetric nonlinear diffusion equation for spread of impurities in gas and solids are obtained and discussed. In this case, the solutions of the nonlinear diffusion equation are similar to solutions of Bernoulli equation. We note that the obtained solutions can be used to describe the shapes of impurity gas of high concentration or smoke clouds.
Źródło:
Acta Physica Polonica A; 2004, 105, 5; 475-483
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Solution of Nonlinear Diffusion Equation in Two-Dimensional Surface
Autorzy:
Janavičius, A. J.
Turskienė, S.
Powiązania:
https://bibliotekanauki.pl/articles/2044566.pdf
Data publikacji:
2005-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
We considered practically important case of nonlinear diffusion in the anisotropic plane where diffusion coefficients for diffusion in x and y axis directions can be different. This equation was transformed using similarity variables. The approximate analytical solution of the transformed equation expressed by power-series expansion for two variables about the zero point including only the first terms. The graphic representations show sufficient accuracy of the obtained analytical solution.
Źródło:
Acta Physica Polonica A; 2005, 108, 6; 979-983
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Solution of Nonlinear Diffusion Equation Describing Interdiffusion of Gases
Autorzy:
Janavičius, A.
Jurgaitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/1585041.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
The diffusion is the result of Brownian movement and occurs with a finite velocity. We consider the nonlinear diffusion equation, with diffusion coefficient directly proportional to the impurities concentration. In this case of diffusion from the constant source, the maximum displacements of diffusing particles are proportional to the square root of diffusion time. This result coincides with Brownian movement theory. The obtained analytically solutions were successfully applied for describing the diffusion and superdiffusion experiments' in solids. After theoretical consideration of application of this equation for diffusion in gases, we are investigating here the binary nonlinear diffusion in gases. We obtained the nonlinear interdiffusion equation, for the spherical symmetric case, and presented the approximate analytical solutions.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 1025-1028
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Nonlinear Diffusion in the Nonisothermical Case
Autorzy:
Janavičius, A. J.
Powiązania:
https://bibliotekanauki.pl/articles/1968857.pdf
Data publikacji:
1998-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
We will discuss the properties of the nonlinear equation in the nonisothermical case. In our previous papers the diffusion coefficient directly proportional to the concentration of the impurities was proposed and it was exactly defined. Now the nonlinear diffusion equation is solved for the temperature and for the diffusion coefficient depending on time in a special way. The temperature function T(t) has the singularity at the free chosen time moment t$\text{}_{0}$. The obtained analytical solutions define the diffusion profiles for increasing temperatures and in the case of excited systems when the vacancies and the impurity's atoms are not in the thermal equilibrium with lattice. Considering the connection between temperature function and the population of excited states for atoms surrounding vacancies the possibility of the superdiffusion is shown.
Źródło:
Acta Physica Polonica A; 1998, 93, 3; 505-512
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Many-Staged Diffusion
Autorzy:
Janavičius, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968915.pdf
Data publikacji:
1998-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
We considered and solved the nonlinear diffusion equation formerly. The more complicated but more useful task of many-staged diffusion is solved in this paper. The obtained solution satisfies the initial distribution of the impurities and can be generalized for many-staged diffusion. Using these solutions we can take into account all the stages of a planary transistor formation.
Źródło:
Acta Physica Polonica A; 1998, 93, 5-6; 731-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Diffusion Equation with Diffusion Coefficient Directly Proportional to Concentration of Impurities
Autorzy:
Janavičius, A. J.
Poškus, A.
Powiązania:
https://bibliotekanauki.pl/articles/2042120.pdf
Data publikacji:
2005-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
Opis:
We analyzed a diffusion model based on the assumption that the sufficient condition for the mass flux at point x+L to be different from zero is a nonzero value of the impurity gradient and of impurity concentration at point x. In our model, the length of the jump of diffusing particles from one equilibrium position to another has a defined value L. By describing variation of impurity concentration with time when the frequency of the jumps depends on coordinates and L, the nonlinear diffusion equation was derived. We found that the diffusion coefficient in this nonlinear equation is directly proportional to the concentration of impurities, as it had been proposed in earliest papers. The derived nonlinear diffusion equation was solved numerically for the case of spherical symmetry.
Źródło:
Acta Physica Polonica A; 2005, 107, 3; 519-524
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pretransition Phenomena in Fast-Proton Conductors
Autorzy:
Waplak, S.
Bednarski, W.
Ostrowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2043554.pdf
Data publikacji:
2005-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.-v
66.30.-h
Opis:
In this paper we present recent experimental results related to nonlinear crystal field fluctuations and current flow in K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ fast-proton conductor far below the transition temperature T$\text{}_{g}$. The results for crystalline and powdered samples are quantitatively explained in the framework of soliton model of charge transport.
Źródło:
Acta Physica Polonica A; 2005, 108, 2; 261-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Investigation of the Cu Ions Diffusion into Bulk Lithium Niobate
Autorzy:
Sugak, D.
Syvorotka, I.
Yakhnevych, U.
Buryy, O.
Martynyuk, N.
Ubizskii, S.
Zhydachevskyy, Ya.
Suchocki, A.
Kumar, H.
Janyani, V.
Singh, G.
Powiązania:
https://bibliotekanauki.pl/articles/1030967.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
78.20.-e
Opis:
Spatial changes of optical properties of bulk LiNbO₃ crystal were investigated after annealing in CuO powder. The incorporation of copper ions into the crystal was confirmed by registration of additional absorption spectra that revealed formation of the absorption bands of both Cu⁺ (400 nm) and Cu²⁺ (1000 nm) ions. The changes of optical absorption caused by thermal treatment were registered along the direction of diffusion by the probe beam perpendicular to this direction. The anisotropy of diffusion was revealed. The maxima were observed on the depth dependences of additional absorption both for the wavelengths of 400 and 1000 nm for all main crystallographic directions. The concentrations of copper ions were calculated in accordance with the Smakula-Dexter formula. The X-ray diffraction study revealed reflexes which probably belong to CuNb₂O₆, CuNbO₃ and CuO. The halo was observed on these diffraction patterns that confirms the formation of the scattering centers (about 1 nm in diameter) in the near-surface region.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 965-972
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Co Ions Diffusion in Gd₃Ga₅O₁₂ Single Crystals
Autorzy:
Sugak, D.
Syvorotka, I.
Yakhnevych, U.
Buryy, O.
Vakiv, M.
Ubizskii, S.
Włodarczyk, D.
Zhydachevskyy, Ya.
Pieniążek, A.
Jakiela, R.
Suchocki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1030989.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
78.20.-e
Opis:
Spatial changes of properties of Gd₃Ga₅O₁₂ (GGG) single crystals caused by diffusion of cobalt ions during high-temperature annealing (1200°C, 24 h) in Co₃O₄ powder are investigated. The registration of these changes was carried out by optical spectrophotometry, microscopy and micro-Raman scattering methods. Changes in structure of near-surface layers of the crystal were investigated by X-ray diffraction technique. It was shown that the additional absorption induced by annealing is related to intra-center optical transitions in Co²⁺ ions, which occupy tetrahedral positions in the garnet structure at the distances of 250-500 μm from the crystal surface. The dependence of induced absorption with depth has got a non-monotonous character with a maximum at 400 μm. A comparison of the results obtained by different methods allows to suppose that the thermal treatment of GGG in the presence of cobalt ions leads to formation of the structurally and chemically non-uniform layer with a width about 500 μm.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 959-964
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superdiffusion in Si Crystal Lattice Irradiated by Soft X-Rays
Autorzy:
Janavičius, A.
Balakauskas, S.
Kazlauskienė, V.
Mekys, A.
Purlys, R.
Storasta, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812042.pdf
Data publikacji:
2008-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
78.70.Ck
Opis:
We considered the reasons of superdiffusivity and measured profiles of boron and phosphorus in crystalline silicon at room temperature. The superdiffusivity or ultrafast diffusion of metastable vacancies at room temperature in Si crystal irradiated by soft X-rays was obtained experimentally. In this work, we presented experimentally obtained diffusion coefficients of singly and doubly negatively charged long-lived excited vacancies. These high concentration charged metastable vacancies (about $10^{13} cm^{-3}$) at room temperature can very fast diffuse changing electrical conductivity and the Hall mobility of carriers. We measured the superdiffusivity of negatively charged vacancies, generated by the Auger effect in the regions of the sample, which were not affected by X-rays. In this paper, we presented the obtained superdiffusion profiles of boron and phosphorus in crystalline silicon measured with secondary-ion mass spectrometer.
Źródło:
Acta Physica Polonica A; 2008, 114, 4; 779-790
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Thermodiffusion Inertia in Metal Films Heated with Ultrashort Laser Pulses
Autorzy:
Janavičius, A. J.
Turskienė, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047101.pdf
Data publikacji:
2006-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
79.20.Ds
Opis:
Previously, we considered the analytical solution of nonlinear diffusion equation in two-dimensional surface. This allows us to consider the same nonlinear heat conduction equation for metals heated by a picosecond laser. After fast thermalization (within a few femtoseconds) of the laser energy and electron excitation in the conductivity band, electrons ballistically diffuse and transfer their energies to the target atoms and equilibrium electrons from the conductivity band. In this case, we have thermal diffusion of nonequilibrium excited electrons and thermal inertia for thermodiffusion. The relaxation time of excited conductivity electrons is directly connected with thermal inertia and depends on electron-electron collision frequencies. The theoretical temperature surface plots for the thermodiffusion of excited electrons were obtained from analytical solutions of nonlinear thermodiffusion equations.
Źródło:
Acta Physica Polonica A; 2006, 110, 4; 511-521
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Diffusion in Excited HgCdTe and Si Crystals
Autorzy:
Janavičius, A. J.
Norgėla, Ž.
Purlys, R.
Powiązania:
https://bibliotekanauki.pl/articles/2036987.pdf
Data publikacji:
2003-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
66.30.Hs
78.70.Ck
Opis:
We discuss the properties of the nonlinear diffusion equation for the case of diffusion in excited systems. The diffusion coefficient is directly proportional to the concentration of impurities and depends on time in a special way. For the description of the excited systems, we used a special temperature function, which defined the time dependent diffusion coefficient and the Boltzmann distribution of the excited vacancies or impurity atoms in solids. This model was used for the approximation of indium concentration profiles in HgCdTe of a rapid diffusion component and very fast diffusion of metastable vacancies irradiated by soft X-rays in an excited Si crystal.
Źródło:
Acta Physica Polonica A; 2003, 104, 5; 459-467
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast Diffusion of Metastable Vacancies in Surface of Excited Si Crystals
Autorzy:
Janavičius, A. J.
Turskienė, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047100.pdf
Data publikacji:
2006-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.-h
66.30.Hs
78.70.Ck
Opis:
We considered the practically interesting, very fast nonlinear diffusion of metastable vacancies in the surface of Si crystal, excited by soft X-rays. Here we used experimentally defined diffusion coefficients of singly and doubly negatively charged very fast vacancies generated by soft X-rays. These high concentration (about 10$\text{}^{13}$ cm$\text{}^{-3}$) metastable vacancies at room temperature can diffuse and exist in the crystal for a very long time (about 24 hours for not so fast neutral vacancies) changing electrical conductivity, the Hall mobility of carriers and generating some resonance phenomena in the lattice of Si crystal. We measured superdiffusivity of negatively charged vacancies, generated by the Auger effect in the regions of the sample, where X-rays did not acted. In the paper we modified the formerly obtained analytical solution of nonlinear diffusion equation for calculation of distribution of vacancies in two-dimensional surface.
Źródło:
Acta Physica Polonica A; 2006, 110, 4; 505-510
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitude Modulation and Demodulation in Strain Dependent Diffusive Semiconductors
Autorzy:
Ghosh, S.
Yadav, N.
Powiązania:
https://bibliotekanauki.pl/articles/2047356.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Mw
72.50.+b
66.30.-h
Opis:
In communication processes, amplitude modulation is very helpful to save power by using a single band transmission. Thus in this paper authors have explored the possibility of amplitude modulation as well as demodulation of an electromagnetic wave in a transversely magnetized electrostrictive semiconductor. The inclusion of carrier diffusion and phenomenological damping coefficient in the nonlinear laser-semiconductor plasma interaction adds a new dimension to the analysis present in this paper. This problem is analyzed in different wave number regimes over a wide range of cyclotron frequencies. It is found that the complete absorption of the waves takes place in all the possible wavelength regimes when the cyclotron frequency (ω$\text{}_{c}$) becomes exactly equal to (ν$\text{}^{2}$+ω$\text{}_{0}^{2}$)$\text{}^{1}\text{}^{/}\text{}^{2}$ in absence of damping parameter. It has also been seen that diffusion of charge carriers modifies amplitude modulation and demodulation processes significantly. The damping parameter plays a very important role in deciding the parameter range and selecting the side band mode that will be modulated by the above-mentioned interaction.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 29-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of "order-order" Relaxations in Ni$\text{}_{3}$Al Studied by Computer Simulation
Autorzy:
Oramus, P.
Kozubski, R.
Cadeville, M. C.
Pierron-Bohnes, V.
Pfeiler, W.
Powiązania:
https://bibliotekanauki.pl/articles/2011010.pdf
Data publikacji:
1999-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.20.Dd
66.30.-h
81.30.Hd
Opis:
The experimental investigations of "order-order" kinetics in Ni$\text{}_{3}$ Al-based L1$\text{}_{2}$-ordered intermetallic compounds revealed the relaxation curves composed of two parallel processes considerably differing in relaxation rates. A simple Ising-type model based on a vacancy mechanism of atomic jumps was used to carry the Monte Carlo simulations of long-range-order relaxations in a binary A$\text{}_{3}$B system with L1$\text{}_{2}$-type superstructure. The simulated relaxation curves fitted weighted sums of two exponentials with significantly different relaxation times. It was found out that the fast relaxation process is controlled by the dynamics of the minority B-atom jumps.
Źródło:
Acta Physica Polonica A; 1999, 96, 1; 153-160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physics with Chemically and Isotopically Pure Semiconductors
Autorzy:
Haller, E. E.
Powiązania:
https://bibliotekanauki.pl/articles/1929597.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
63.20.-e
66.30.-h
28.60.+s
Opis:
Chemically and isotopically pure semiconductors offer a wealth of interesting physics. We review a number of impurity complexes which were discovered in ultra-pure germanium. They have led the way to the widely pursued studies of hydrogen in numerous semiconductors. Isotope related effects and processes include neutron transmutation doping, a technique used for a number of silicon and germanium devices: isotopically pure and deliberately mixed crystals of germanium have been grown recently and have been used to study the dependence of the indirect bandgap and phonon properties on the mass and mass disorder of the nuclei. The large number of stable isotopes of the various semiconductors present a great potential for basic and applied studies. Semiconductor isotope engineering may become a reality because of the new economic and political world order.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 395-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vapour Absorption in Melamine-Formaldehyde Resin
Autorzy:
Wawryszczuk, J.
Ciesielski, K.
Goworek, J.
Powiązania:
https://bibliotekanauki.pl/articles/2025738.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
36.10.Dr
61.41.+e
66.30.-h
Opis:
The effects of vapour absorption on positron annihilation in cross-linked polymer were investigated. Contrary to linear polymers, absorption of vapour in cross-linked resin leads to the shortening of o-Ps lifetime. In vacuum absorbed molecules diffuse out. At room temperature desorption of hexane and hexanol is not complete; full elimination of absorbed molecules requires sample temperature increase.
Źródło:
Acta Physica Polonica A; 2001, 99, 3-4; 523-528
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying Static, Dynamic and Transport Properties of Mg₃Bi₂
Autorzy:
Kayadibi, F.
Günay, S.
Taşseven, Ç.
Powiązania:
https://bibliotekanauki.pl/articles/1401914.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
83.10.Rs
34.20.Gj
66.30.H-
66.30.Fq
62.20.-x
65.40.-b
Opis:
In this study, new potential parameters for Mg₃Bi₂ are proposed which is the Born-Mayer-Huggins type potential. Static, dynamic and transport properties are studied for this material from 300 K up to 1600 K with classical molecular dynamics simulation. Mechanical properties; like elastic constants ($C_{11}$, $C_{12}$, $C_{13}$, $C_{33}$, $C_{44}$), bulk modulus and shear modulus are found. All these data are compared with the limited number of experimental and first-principle studies. Our results give a good description of the Mg₃Bi₂ system: lattice constants, α → β transition temperature, melting temperature, diffusion coefficient, density and mechanical properties are promising.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 440-446
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Diffusion on (ZrO$\text{}_{2}$)$\text{}_{0.8}$(Y$\text{}_{2}$O$\text{}_{3}$)$\text{}_{0.2}$ Ceramic
Autorzy:
Sharma, S. V.
Chand, P.
Powiązania:
https://bibliotekanauki.pl/articles/1933619.pdf
Data publikacji:
1995-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.-d
64.80.Gd
66.30.-h
76.30.Fc
81.20.Lb
Opis:
Effect of iodine and lithium diffusion on undoped and doped (with transition metal ions: Ti, V, Ni, Fe, Cu, Co and Mn) samples of polycrystalline (ΖrO$\text{}_{2}$)$\text{}_{0.8}$(Y$\text{}_{2}$O$\text{}_{3}$)$\text{}_{0.2}$ ceramic has been investigated using X-ray diffraction, scanning electron microscopy and electron paramagnetic resonance.
Źródło:
Acta Physica Polonica A; 1995, 88, 3; 503-509
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the Electron Theory of Sintering to the Ferrite Systems
Autorzy:
Kopayev, A.
Bushkova, V.
Powiązania:
https://bibliotekanauki.pl/articles/1549694.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.10.+z
36.20.Hb
66.30.-h
77.84.Bw
81.20.Ev
85.70.Ge
Opis:
The compositions of magnesium-zinc ferrites $(Mg_{0.56}Zn_{0.44})_{1-y}Fe_{2 + 2y/3}O_{4}$, where y = -0.05, 0, +0.05 were sintered at temperatures 1230 and 1280°C. The analysis of the kinetics of sintering was carried out by using the Ivensen model. It was shown that at decrease of y the sintering rate increases. The analysis of the electronic configurations of the cations in the ferrite composition showed the possibility of applying the Samsonov electronic theory of sintering powders to them. Magnetic permeability of the studied chemical compositions increases with increase of the density of ferrites as well as with the temperature and the time of isothermal soaking.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 30-33
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic Characteristics of 1D Structures
Autorzy:
Jaćimovski, S.
Raković, D.
Powiązania:
https://bibliotekanauki.pl/articles/1503228.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.e
63.20.D
63.20.dk
63.20.kd
63.20.kg
63.20.kp
65.40.Ba
66.30.h
Opis:
In this paper 1D crystal lattice is analyzed within harmonic approximation, with one atom per elementary cell and nearest neighbor interaction included. For this type of crystal lattice dispersion relations are well known. Thermodynamic functions (specific heat and phonon thermal conductivity) are calculated via phonon density of states given in exact form. Thermodynamic variables are calculated for a whole temperature range. In limiting cases of low and high temperatures these thermodynamic variables can be found in analytic forms. For thermal conductivity the results of Callaway model for exact phonon density of states are compared with the results of Callaway model for Debye approximation of phonon density of states.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 231-233
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Contribution in Thermodynamics and Transport Properties of Ultrathin Ceramic Films
Autorzy:
Jaćimovski, S.
Šetrajčić, J.
Jaćimovski, M.
Stojanović, V.
Powiązania:
https://bibliotekanauki.pl/articles/1205327.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.-h
73.61.-r
74.25.fc
66.30.Xj
65.40.-b
Opis:
The dispersion law, density states of phonons, thermodynamics properties and thermal conductivity was analyzed in this paper. It has been shown that at low temperatures, thermal conductivity of thin film is considerably lower that of bulk-structure. It turned out that phonons in thin film require activation energy for exciting. This leads to extremely low specific heat and specific conductivity at low temperatures. Consequences of quoted facts were discussed in detail and their influence on kinetic and thermodynamic properties of thin films is estimated.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 811-819
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Cavity Enhanced Photonic Devices
Autorzy:
Bugajski, M.
Muszalski, J.
Ochalski, T.
Kątcki, J.
Mroziewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/2030303.pdf
Data publikacji:
2002-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
78.66.Fd
78.55.-m
78.67.De
78.45.+h
78.47.+p
Opis:
In the present paper we review our recent works on technology, basic physics, and applications of one-dimensional photonic structures. We demonstrate spontaneous emission control in In$\text{}_{x}$Ga$\text{}_{1-x}$As/GaAs planar microcavities with distributed Bragg reflectors. In general, observed trends are in agreement with theoretical predictions. We also demonstrate the operation of resonant-cavity light emitting diodes and optically pumped vertical cavity light emitting diodes developed recently at the Department of Physics and Technology of Low-Dimensional Structures of the Institute of Electron Technology.
Źródło:
Acta Physica Polonica A; 2002, 101, 1; 105-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Characterization of Interdigitated Humidity Sensors Based on CNT Modified Calixarene Molecules
Autorzy:
Özbek, C.
Culcular, E.
Okur, S.
Yılmaz, M.
Kurt, M.
Powiązania:
https://bibliotekanauki.pl/articles/1400035.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.je
65.40.gp
65.40.gk
65.40.gd
64.70.fm
64.10.+h
51.10.+y
Opis:
In this study, we report on the optimization and characterization of chloroform soluble calix[4]arene derivative as a humidity sensor based on electrical properties. Due to the fact that calix[4]arene molecules are nonconductive, we modified the calix[4]arene molecules with carbon nanotubes with electrostatic bond in order to increase the conductance of calix[4]arene molecule (5,11,17,23-tetra-ter-butyl-25,27-dehydrazinamidcarbonilmetoxy-26,28-dehydroxy-kalix[4]aren). Using photolithography technique, we fabricated interdigitated gold electrodes with 3 micrometers separation to investigate the electrical properties of carbon nanotubes modified calix[4]arene molecule where we used dropcast method to form a thin film of carbon nanotubes modified calix[4]arene molecule on the gold electrodes. Our reproducible experimental results indicated that the chloroform soluble carbon nanotubes modified calix[4]arene films have great potential for humidity sensing applications at room temperature operations.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 461-463
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gas Sensing Properties of Carbon Nanotubes Modified with Calixarene Molecules Measured by QCM Techniques
Autorzy:
Mermer, Ö.
Okur, S.
Sümer, F.
Özbek, C.
Sayın, S.
Yılmaz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1491414.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
66.30.je
65.40.gp
65.40.gk
65.40.gd
64.70.fm
64.10.+h
51.10.+y
Opis:
This study focuses on the characterization and optimization of calixarene modified carbon nanotube thin films for gas detection. Calixarene molecules were synthesized individually by considering their functional groups to attract the gas. Calixarene modified carbon nanotube based sensors were fabricated using drop-casting method on a quartz crystal microbalance gold electrode. Carbon monoxide, carbondioxide, oxygen and dry air were used as active gases for adsorption process, while high-purity nitrogen gas was used for desorption process. The selectivity and sensitivity of calixarene modified carbon nanotube are investigated in detail. Our experimental results show that functional calixarene modified carbon nanotube coated quartz crystal microbalance sensors are very sensitive and selective to gas of $CO_2$ at room temperature operation.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 240-242
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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