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Tytuł:
On the Thermodynamics of the Hopfield Neural Network with External Field
Autorzy:
Ulaczyk, J.
Kosiński, R. A.
Zagórski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2036992.pdf
Data publikacji:
2003-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Hk
Opis:
In the paper thermodynamic properties of an artificial neural network are analyzed in a way analogous to spin glasses theory. Synaptic connections are calculated numerically according to the Hebb rule and their distribution is obtained for different characteristics of stored patterns. The phase diagrams and magnetization are established in dependence on the temperature of the network and the external field (threshold). It was showed that changing control parameters typical of artificial neural network (i.e. number of stored patterns and pattern bias level) one obtains the results similar to the Sherrington-Kirkpatrick model of spin glass.
Źródło:
Acta Physica Polonica A; 2003, 104, 5; 479-486
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cathodoluminescence Studies of Polytype Structure in Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se
Autorzy:
Cichos, A.
Firszt, F.
Falke, U.
Lenzner, J.
Męczyńska, H.
Hietschold, M.
Powiązania:
https://bibliotekanauki.pl/articles/1995011.pdf
Data publikacji:
1999-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
Opis:
Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se crystals grown by Bridgman method show spatial transition from sphalerite (3C) to wurzite structure (2H) with increasing Mg content (x). Within the transition range, near x=0.19, coexistence of hexagonal and cubic structure results in the formation of polytype sequences of 3C-8H-4H-2H. We have investigated the spatial distribution of the polytypes in Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se mixed crystals with a value of x close to that of the phase transition using spectrally as well as spatially resolved cathodoluminescence. Three emission bands in the cathodoluminescence spectrum have been observed, two strong lines at 2.99 eV and 2.965 eV, and a weak shoulder at 2.95 eV. The lines at 2.965 and 2.99 eV are known in the literature as an exciton recombination in the 8H and 4H polytype structure. We have found the third one at 2.95 eV to be due to luminescence in the 3C structure. These results demonstrate the usefulness of cathodoluminescence measurements for investigations of spatial distribution of inhomogeneities of mixed semiconductors.
Źródło:
Acta Physica Polonica A; 1999, 95, 2; 269-274
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of the Kinetics for Rhodium Adsorption onto Gallic Acid Derived Polymer: the Application of Nonlinear Regression Analysis
Autorzy:
Can, M.
Powiązania:
https://bibliotekanauki.pl/articles/1193890.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.30.Hk
Opis:
The kinetic behaviors of solute adsorption at solid/solution interfaces of rhodium (III) complexes from chloride solutions (1 M HCl) onto gallic acid formaldehyde resol polymer were studied by batch mode. Kinetics was analyzed by the pseudo first-order, the pseudo second-order, the Elovich and the intraparticle diffusion kinetic equations using nonlinear regression analysis. The rate constants of four models were calculated. The Non-linear Chi-square analysis and correlation coefficients have been calculated in order to assess which model provides the best fitting predicted data with experimental results. The pseudo second-order equation provides the best fit to experimental data. The first initial kinetics is governed by the rate of surface reaction. When the adsorbed amount reaches about 95% of the equilibrium coverage in the first sixty minutes, it switches to another kinetics governed by the rate of intraparticle diffusion. The proposed adsorption of the aquachlororhodium (III) species mostly takes place via a ligand exchange mechanism.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1308-1310
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature on the Ion Beam Induced Luminescence of Oxide Powders Doped with Rare Earth Elements
Autorzy:
Gawlik, G.
Panczer, G.
Moncoffre, N.
Jagielski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1400478.pdf
Data publikacji:
2013-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
Opis:
The hydrogen ion beam induced luminescence of gadolinium oxide $Gd_2O_3$ doped with 1% of holmium (Ho) and 1% of bismuth (Bi) was investigated. Degradation of the holmium related 549 nm ion beam induced luminescence line intensity during hydrogen ion irradiation was observed. Two different mechanisms of the ion beam induced luminescence degradation has been proposed: the first one related to the accumulation of ion induced target material damage and the second mechanism related to the target temperature growth during ion beam bombardment. The experimental method for separation of both mechanisms effects was proposed and demonstrated.
Źródło:
Acta Physica Polonica A; 2013, 123, 5; 920-922
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rhodium Adsorption on Gallic Acid Resol Resin
Autorzy:
Can, M.
Powiązania:
https://bibliotekanauki.pl/articles/1401365.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.30.Hk
Opis:
A new adsorbent resin has been developed by immobilizing gallic acid with formaldehyde, and its adsorption properties to $Rh^{3+}$ were reviewed with respect to the collection in aqueous solution. Linear and nonlinear regression procedures have been applied to the Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich, and Redlich-Peterson isotherms. The resin exhibited good adsorption capacity towards $Rh^{3+}$ from acidic aqueous solutions ($[H^{+}]$=1 M, $[Cl^{-}]$=1 M). The equilibrium adsorption capacity at 293 K was up to 69.43 mg $g^{-1}$. The adsorption isotherms could be well described by Langmiur equation. The experimental studies suggested that gallic acid formaldehyde resin was effective for the adsorption of $Rh^{3+}$ from chloride acid solutions, and the loaded $Rh^{3+}$ could be easily desorbed from the 1 M HNO₃ + 0.1 M NaClO₃ solution mixture with a hundred percent efficiency. Thermodynamic parameters such as the entropy change, enthalpy change and Gibbs free energy change were calculated. The adsorption of Rh^{3+} was found to be an endothermic adsorption process. This suggested that the resin can be used as an active biosorbent for the recovery of $Rh^{3+}$ from 1 M HCl concentrated acid solution.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1301-1307
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Light Emission Properties of GaN-Based Laser Diode Structures
Autorzy:
Godlewski, M.
Phillips, M. R.
Czernecki, R.
Targowski, G.
Perlin, P.
Leszczyński, M.
Figge, S.
Hommel, D.
Powiązania:
https://bibliotekanauki.pl/articles/2043715.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.30.-z
78.60.Hk
68.37.Hk
Opis:
Cathodoluminescence is applied for evaluation of in-depth and in-plane variations of light emission from two types of GaN-based laser diode structures. We evaluate in-depth properties of the laser diode emission and demonstrate that potential fluctuations still affect emission of laser diodes for e-beam currents above thresholds for a stimulated emission.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 675-680
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Green Synthesis of Pd Nanoparticles via Gallic Acid
Autorzy:
Can, M.
Powiązania:
https://bibliotekanauki.pl/articles/1033577.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.30.Hk
Opis:
A facile, eco-friendly, room-temperature method for rapid one-pot synthesis of Pd metallic nanoparticles has been developed based on the successive reduction of Pd(II) precursors with gallic acid in an aqueous environment. The morphology and surface analysis of the resulting Pd nanoparticles were confirmed by aberration corrected scanning transmission electron microscopy followed by X-ray photoelectron spectroscopy. The particle size of palladium nanoparticles was calculated as 16 nm. This study demonstrates that the synthesis of nanoparticles (reduction and stabilization) can be effectively achieved using gallic acid.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 569-570
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dark Photon Searches with the KLOE Detector
Autorzy:
Bloise, C.
Powiązania:
https://bibliotekanauki.pl/articles/1402644.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
13.66.Hk
Opis:
The KLOE-2 experiment at the Frascati Laboratory has recently obtained several results on dark photon searches. We present published analyses and the preliminary results of the study of the final states with e⁺e¯γ, and μ⁺μ¯ plus missing energy.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1565-1567
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Preparation of Core-Shell $Al_2O_3//Cu$ Composite Powders by Electroless Plating in the Alkaline Solution
Autorzy:
Uysal, M.
Karslioğlu, R.
Alp, A.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399707.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Hk
Opis:
In this study, Cu-coated $Al_2O_3$ composite powders were synthesized by using electroless plating method. The influence of the plating bath composition and ceramic powder concentration on the Cu plating was characterized by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction techniques. The results showed that the electroless bath composition plays an important role for the structure of nano core-shell $Al_2O_3//Cu$ composite powders. The content of copper in the composite powders could be effectively controlled by adjusting the content of copper sulfate and formaldehyde in the plating solution. Furthermore, the pretreatment of the $Al_2O_3$ powders is also a key factor to form a uniform shell copper layer coating on $Al_2O_3$ particles.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 238-240
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationship between Sample Morphology and Carrier Diffusion Length in GaN Thin Films
Autorzy:
Godlewski, M.
Goldys, E. M.
Phillips, M.
Böttcher, T.
Figge, S.
Hommel, D.
Czernecki, R.
Prystawko, P.
Leszczynski, M.
Perlin, P.
Wisniewski, P.
Suski, T.
Bockowski, M.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035593.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ff
61.72.Mm
68.37.Hk
78.60.Hk
Opis:
Scanning and spot-mode cathodoluminescence investigations of homo- and hetero-epitaxial GaN films indicate a surprisingly small influence of their microstructure on overall intensity of a light emission. This we explain by a correlation between structural quality of these films and diffusion length of free carriers and excitons. Diffusion length increases with improving structural quality of the samples, which, in turn, enhances the rate of nonradiative recombination on structural defects, such as dislocations.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 627-632
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cathodoluminescence Measurements at Liquid Helium Temperature of Poly- and Monocrystalline ZnO Films
Autorzy:
Witkowski, B.
Wachnicki, Ł.
Jakieła, R.
Guziewicz, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1492546.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
77.55.hf
68.37.Hk
61.72.Ff
Opis:
Scanning electron microscopy, cathodoluminescence and secondary ion mass spectroscopy investigations are used to study an inter-link between structural quality, elements distribution and light emission properties of ZnO poly- and monocrystalline films grown by the atomic layer deposition. Cathodoluminescence and scanning electron microscopy investigations were performed at liquid helium temperature for four different types of ZnO films deposited on different substrates.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-028-A-030
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Secondary Electroluminescence on Cathodoluminescence and Other Luminescence Measurements
Autorzy:
Pluska, M.
Czerwinski, A.
Szerling, A.
Ratajczak, J.
Kątcki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1198425.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
85.30.De
61.72.-y
68.37.Hk
Opis:
Cathodoluminescence and photoluminescence measurements are commonly accepted as revealing local properties of a specimen region excited by a beam of electrons or photons. However, in the presence of a strong electric field (e.g. a junction) an electron (or light/laser) beam-induced current is generated, which spreads over the structure. A secondary non-local electroluminescence, generated by this current and detected together with the expected luminescence signal, may strongly distort measurement results. This was confirmed by cathodoluminescence measurements on test structures prepared by focused ion beam on AlGaAs/GaAs/InGaAs laser heterostructures. Methods for minimizing the distortion of measured luminescence signals are presented.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 1027-1032
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cathodoluminescence Profiling of InGaN-Based Quantum Well Structures and Laser Diodes - In-Plane Instabilities of Light Emission
Autorzy:
Godlewski, M.
Ivanov, V. Yu.
Goldys, E. M.
Phillips, M.
Böttcher, T.
Figge, S.
Hommel, D.
Czernecki, R.
Prystawko, P.
Leszczynski, M.
Perlin, P.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2036870.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ff
61.72.Mm
68.37.Hk
78.60.Hk
Opis:
Instabilities of light emission and also of stimulated emission in series of GaN epilayers and InGaN quantum well structures, including laser diode structures, are studied. A stimulated emission is observed under electron beam pumping. This enabled us to study light emission properties from laser structures and their relation to microstructure details. We demonstrate large in-plane fluctuations of light emission and that these fluctuations are also present for excitation densities larger than the threshold densities for the stimulated emission.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 689-694
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the Crystallization Process of Eu$\text{}^{3+}$:CaSiO$\text{}_{3}$ Gel Using Optical and Thermal Methods
Autorzy:
Andrić, Ž.
Krsmanović, R.
Marinović-Cincović, M.
Dramićanin, T.
Šećerov, B.
Dramićanin, M. D.
Powiązania:
https://bibliotekanauki.pl/articles/2047860.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Gt
61.46.Hk
68.37.Hk
78.67.Bf
81.70.Pg
Opis:
Alkoxy sol-gel technique is an important preparation method for production of rare-earth based phosphors. Crystallization of gel provides a way to prepare phosphors on lower working temperatures than those required for the solid state reactions. CaSiO$\text{}_{3}$ gel samples were obtained through hydrolysis-condensation reactions of tetraethylorthosilicate as silica source. In this work we studied the process of crystallization of Eu$\text{}^{3+}$-activated CaSiO$\text{}_{3}$ gel and decomposition of organic precursors by means of thermal analysis and infrared spectroscopy. Results of scanning electron microscopy and energy-dispersion spectrometry are used to check chemical composition and morphology of synthesized material. Emission spectra and emission lifetime measurements are performed to investigate luminescence properties of Eu$\text{}^{3+}$ doped CaSiO$\text{}_{3}$ powder.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 969-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Thermal Investigation of Sol-Gel Derived Eu$\text{}^{3+}$:Y$\text{}_{2}$SiO$\text{}_{5}$ Nanoparticles
Autorzy:
Krsmanović, R.
Andrić, Ž.
Marinović-Cincović, M.
Zeković, I.
Dramićanin, M. D.
Powiązania:
https://bibliotekanauki.pl/articles/2047861.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Gt
61.46.Hk
68.37.Hk
78.67.Bf
81.70.Pg
Opis:
Investigation done on Y$\text{}_{2}$SiO$\text{}_{5}$ nanoparticles doped with Eu$\text{}^{3+}$ ions obtained with the alkoxy sol-gel route is presented in this paper. We investigate the optical and thermal properties of obtained material during the conversion of the gel into nanocrystalline form. Fourier transform infrared spectroscopy and fluorescence spectroscopy of Eu$\text{}^{3+}$ ions are used for the optical characterizations, while thermal analysis is done with thermogravimetric-differential thermal analysis technique. Material exhibits characteristic luminescence emission of the trivalent europium ion.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 975-980
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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