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Tytuł:
Settling Time Testing of Fast DACs
Autorzy:
Kvedaras, R.
Kvedaras, V.
Ustinavicius, T.
Powiązania:
https://bibliotekanauki.pl/articles/1505231.pdf
Data publikacji:
2011-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Dz
07.05.Hd
07.05.Kf
07.05.Tp
Opis:
New specialized sampling converter for signal timescale transformation and algorithm of digital signal processing for automated measurement of settling times of fast digital-to-analogue converters is represented. The new sampling device with numerically controlled oscillators allows us realization of different types of the timescale transformation. Usage of ΣΔ analogue-to-digital converter and first-in first-out memory allows us significant simplification of the device. The equations of timescale transformation ratio and sampling step are presented. A method using a brick-wall comb filter in frequency domain to filter measurement signal has been developed. It is shown that such filtering allows us significant reduction of noise of measurement signal. A new method and algorithm using a brick-wall comb filter and averaging of filtered signal has been developed. Results of the research of developed digital signal processing algorithm are submitted.
Źródło:
Acta Physica Polonica A; 2011, 119, 4; 521-527
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proposal of a Cost-Saving and Risk Prevention Mechatronic System for Water Consumption Systems of Buildings
Autorzy:
Karayel, D.
Ozkan, S.
Atali, G.
Ceylan, N.
Kilic, R.
Powiązania:
https://bibliotekanauki.pl/articles/1031258.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.62.+q
07.05.Dz
07.10.-h
Opis:
This study aims to develop an integrated control system to prevent the indoor loss of water. In general, these losses occur while using the hot water, because of forgetting to close the water batteries during the water cuts, or due to faults in washing machines, dishwashers and indoor plumbing systems. In this study, a specialized solution is developed for each type of losses. Then, the developed three subsystems were combined and transformed into an integrated system. This study shows that water losses in the housing can be prevented by using advanced technologies. There are similar systems in practice, but this study is different from the others with regard to its holistic approach, addressing all three problems together. The contribution of the system to economic and social life will be great, when water saving and environmental damage are considered.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 604-607
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geometric Phase for Analytically Solvable Driven Time-Dependent Two-Level Quantum Systems
Autorzy:
Mendaš, I.
Burić, N.
Popović, D.
Prvanović, S.
Radonjić, M.
Powiązania:
https://bibliotekanauki.pl/articles/1204876.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Aa
03.65.Vf
07.05.Dz
Opis:
Geometric phase for novel analytical solutions (Barnes and Das Sarma) of time-dependent two-level quantum systems is discussed, specifically for a general single-axis driving term, which is represented by a function J(t) in the Hamiltonian, and its corresponding evolution operator. It is demonstrated how general results for corresponding phases (total, dynamic and geometric) can be obtained. Using a specific case, it was found that over time in which the driving field is appreciably different from zero, the corresponding geometric phase changes (in the specific example by Δ β ≈ 0.8 radians) thus enabling detection. The results are relevant to qubit control and to quantum computing applications.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 670-672
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a Single Line Half Duplex Protocol for Mechanical Rotary Table Systems
Autorzy:
Ozkan, S.
Atali, G.
Boru, B.
Karayel, D.
Powiązania:
https://bibliotekanauki.pl/articles/1031133.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Hd
07.50.-e
89.70.Hj
07.05.Dz
45.80.+r
Opis:
In this study, a new communication protocol, which addresses the rotary table, has been designed. Developed system works over a single line and is using slip rings. The designed communication protocol ensures the half duplex communication for multiple stations over a single cable. During the protocol design, media access methods, coding techniques and multi-node synchronization techniques were examined. These techniques have been adapted, updated and combined for the study, during the formation of the communication protocol. The designed protocol was tested and verified in the simulation environment with original software, on the microcontrollers. The protocol is aimed to be open source, flexible, easily applicable and a new solution for the distributed control problems in the field of automation and for the rotary table systems in particular.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 749-752
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State-space modeling of an EPW in discrete time and an observer design for state variable estimation
Autorzy:
Özdemir, A.
Erdem, Z.
Usuman, I.
Powiązania:
https://bibliotekanauki.pl/articles/1068329.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.30.Yy
89.20.Kk
02.30.Cj
02.70.-c
07.05.Dz
Opis:
The purpose of this study is to obtain the dynamic model of an electrical powered wheelchair and to estimate the state variables of right and left DC motor currents with the designed observer. First, the dynamic equations are written and then discrete-time state space model of the electrical powered wheelchair is directly obtained from this dynamic equations. Discrete time state space model of the electrical powered wheelchair is verified with the transfer function obtained using the dynamic equations. In addition, the accuracy of the estimated left and right DC motor current values are validated in the simulation results.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 228-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication, Structural Characterization and Optical Properties of the Flower-Like ZnO Nanowires
Autorzy:
Feng, L.
Liu, A.
Ma, Y.
Liu, M.
Man, B.
Powiązania:
https://bibliotekanauki.pl/articles/1538755.pdf
Data publikacji:
2010-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Bc
81.05.Dz
81.10.Aj
Opis:
Multipod flower-like zinc oxide (ZnO) nanowires have been successfully synthesized on Si(111) substrates using a pulsed laser deposition prepared Zn film as "self-catalyst" by the simple thermal evaporation oxidation of the metallic zinc powder at 850°C without any other catalysts or additives. The pre-deposited Zn films by pulsed laser deposition on the substrates can promote the formation of the ZnO nuclei effectively. Also it can further advance the growth of the flower-like ZnO nanowires accordingly. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier transform infrared spectrum, and photoluminescence were used to analyze the structure, morphology, composition and optical properties of the as-synthesized products. The results demonstrate that the nanowires were single crystalline with hexagonal wurzite structure, grown along the [0001] in the c-axis direction. Room temperature photoluminescence spectrum of the ZnO nanowires shows a nearband-edge ultraviolet emission (peak at ≈ 384 nm) and a deep-level green emission (peak at ≈ 513 nm). In addition, the growth mechanism of the flower-like ZnO nanowires is discussed in detail.
Źródło:
Acta Physica Polonica A; 2010, 117, 3; 512-517
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemistry of Solids: New Prospects for Extractive Metallurgy, Materials Science and Medicine
Autorzy:
Baláž, P.
Baláž, M.
Achimovičová, M.
Bujňáková, Z.
Dutková, E.
Powiązania:
https://bibliotekanauki.pl/articles/1375090.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
81.20.Wk
81.07.Bc
Opis:
In this review paper recent advances in chalcogene mechanochemistry are described. Three selected areas are being covered, i.e. metallurgy, materials science, and medicine. In extractive metallurgy, the processing of copper arsenic mineral enargite ($Cu_3AsS_4$) with the aim of its dearsenification and subsequent preparation of a new anticancer drug ($Na_3AsS_4$) and of copper in nanocrystalline state ( ≈ 20 nm) illustrate the non-traditional prospect of ore treatment. In material science, the new nanocrystalline semiconductors were synthesized mechanochemically, e.g. selenides of zinc and lead (ZnSe, PbSe) and bismuth sulphide ($Bi_2S_3$). Metal and chalcogene were applied as reaction precursors. In some cases, the amino acids (cystine, cysteine) were applied as sulphur precursor, in order to provide reactive sites on synthesized solid (PbS) for bioconjugation and to prevent agglomeration. The concept of nanomilling is described as a way to prepare effective substances for cancer treatment in medicine. In vitro activity of realgar ($As_4S_4$) as an example is described. In all three areas the focus is aimed also on industrial applications where suitable large-scale mills are described. The described examples represent the contemporary aim of mechanochemists - to prepare substances with the desired properties in a reproducible way under easy-operating, environmentally friendly and essentially waste-free conditions.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 879-883
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Type I CdSe and CdMgSe Quantum Wells
Autorzy:
Rudniewski, R.
Rousset, J.
Janik, E.
Kossacki, P.
Golnik, A.
Nawrocki, M.
Pacuski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1376087.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.-e
81.05.Dz
81.07.-b
Opis:
In this work we present the band gap engineering, epitaxial growth and optical characterization of CdSe/$Cd_{0.9}Mg_{0.1}Se$ and $Cd_{0.9}Mg_{0.1}Se$/$Cd_{0.85}Mg_{0.15}Se$ quantum wells with a thickness ranging from 1 to 15 nm. These structures exhibit strong near-band-gap photoluminescence from helium up to room temperature. The emission energy is tuned in the range from 1.74 to 2.1 eV at 7 K, depending on the thickness and well composition. The most intense photoluminescence (both at 7 and 300 K) was observed for 10 nm thick CdSe/$Cd_{0.9}Mg_{0.1}Se$ wells. Such a structure gives also a sharp emission line (FWHM = 20 meV) at low temperature. The presented quantum wells are well suited for being embedded in lattice matched ZnTe based microcavities.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1167-1170
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical Synthesis and Characterization of II-VI Nanocrystals: Challenge for Cytotoxicity Issues
Autorzy:
Baláž, P.
Jardin, R.
Dutková, E.
Sayagués, M.
Baláž, M.
Mojžišová, G.
Mojžiš, J.
Turianicová, E.
Fabián, M.
Powiązania:
https://bibliotekanauki.pl/articles/1419910.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
81.07.Bc
81.20.Ka
81.20.Wk
Opis:
CdSe@ZnS nanocrystals have been prepared by a two-step solid state mechanochemical synthesis. CdSe prepared from elements in the first step is mixed with ZnS synthesized from zinc acetate and sodium sulfide in the second step. The crystallite size of the new type CdSe@ZnS nanocrystals determined by X-ray diffraction Rietveld refined method was 35 nm and 10 nm for CdSe and ZnS, respectively. Energy dispersive/transmission electron microscopy/energy dispersive spectroscopy methods show good crystallinity of the nanoparticles and scanning electron microscopy elemental mapping illustrate consistent distribution of Cd, Se, Zn and S elements in the bulk of samples. UV-VIS spectra show an onset at 320 nm with calculated bandgap 3.85 eV. This absorption arises from the vibration modes of Zn-S bonds. The nanocrystals show the blue shift from the bandgap of bulk ZnS (3.66 eV). The synthesized CdSe@ZnS nanocrystals have been tested for dissolution, cytotoxicity and L-cysteine conjugation. The dissolution of Cd was less than 0.05 μg $mL^{-1}$ (in comparison with 0.8 μg $mL^{-1}$ which was evidenced for CdSe alone). The very low cytotoxic activity for selected cancer cell lines has been evidenced. CdSe@ZnS nanocrystals coated with L-cysteine are water-soluble and have a great potential in biomedical engineering as fluorescent labels.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 224-229
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of the Ultraviolet Luminescence Intensity from Cd-Doped ZnO Films Caused by Exciton Binding
Autorzy:
Shtepliuk, I.
Lashkarev, G.
Khyzhun, O.
Kowalski, B.
Reszka, A.
Khomyak, V.
Lazorenko, V.
Timofeeva, I.
Powiązania:
https://bibliotekanauki.pl/articles/1492932.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Bf
81.05.Dz
81.07.Bc
Opis:
ZnO films doped with the cadmium (0.4-0.6%) were grown on crystalline sapphire $c-Al_2O_3$ substrates applying radiofrequency magnetron sputtering at the temperature of 400°C in $Ar-O_2$ atmosphere. The as-grown films were investigated in detail using X-ray diffraction, X-ray photoelectron spectroscopy, and cathodoluminescence spectra. The X-ray diffraction analysis revealed that the films possess a hexagonal wurtzite-type structure with the dominant crystallite orientation along the c axis. It was found that the small concentration of the cadmium significantly enhances the ultraviolet emission associated with excitonic transitions. We suggest that this enhancement effect mainly results from appearance of the cadmium isoelectronic traps, which may bind an exciton, thereby increasing the probability of radiation recombination. The effect of Cd isoelectronic impurity on structural and luminescent properties of ZnO films is discussed.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 914-917
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model and Properties of Fullerene-Like and Wurtzite-Like ZnO and Zn(Cd)O Clusters
Autorzy:
Ovsiannikova, L.
Powiązania:
https://bibliotekanauki.pl/articles/1409333.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.55.Et
81.05.Dz
81.07.Bc
Opis:
The electronic structure of the ground state of fullerene-like and wurtzite-like $Zn_{n}O_{n}$ and $Zn_{n - x}Cd_{x}O_{n}$ clusters has been investigated by computer physics methods. A relative evaluation of the stability and band gap width of clusters depending on the number of atoms in the cluster and its geometry has been performed. The model of a fullerene-like $(ZnO)_{60}$ particle with a mixed $sp^3//sp^2$ type of bonds has been constructed. A $(ZnO)_{12}$ cluster of $T_{h}$ symmetry was taken as a base of the model. Within the framework of the B3LYP electron density hybrid functional method with a set of 3-21G(d) split valence basis functions, a numerical investigation of the influence of the incorporation of cadmium (33%) into the ZnO matrix on the electronic structure and the band gap width has been performed.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1062-1064
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Properties of ZnO Nanowires Grown on Ni Substrate
Autorzy:
Zaleszczyk, W.
Fronc, K.
Przeździecka, E.
Janik, E.
Czapkiewicz, M.
Wróbel, J.
Paszkowicz, W.
Kłopotowski, Ł.
Karczewski, G.
Wojtowicz, T.
Presz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1812028.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Bf
81.05.Dz
81.07.Bc
Opis:
Photoluminescence studies of zinc oxide nanowires produced by a carbo-thermal method on a nickel foil substrate are reported. Two types of as-grown samples: the first - containing only buffer film, and the second - containing both zinc oxide nanowires and buffer film grown in the same technological process, were investigated by means of the temperature-dependent photoluminescence. X-ray diffraction measurements of buffer film show that it is polycrystalline and is composed from wurtzite-type ZnO (main phase) and includes minority phases: rock salt type (Ni,Zn)O and hexagonal C₃N₄. The shape of the apparently monocrystalline nanowires is characterized by hexagonal section matching with the expectations of the hexagonal ZnO structure. The presence of LO-phonon replicas in photoluminescence spectra for the second sample is used as an argument for confirmation that ZnO nanowires are single crystalline. The method of growth of ZnO nanowires on nickel oxide opens perspectives to produce $Zn_{1-x}Ni_{x}O$ diluted magnetic semiconductor nanowires.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1451-1456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Properties of ZnCoO Tetrapods and Nanofibers
Autorzy:
Gas, K.
Fronc, K.
Dziawa, P.
Knoff, W.
Wojciechowski, T.
Zaleszczyk, W.
Baranowska-Korczyc, A.
Morhange, J.
Paszkowicz, W.
Elbaum, D.
Karczewski, G.
Wojtowicz, T.
Szuszkiewicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/1791329.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Bf
81.05.Dz
81.07.Bc
Opis:
In this paper the physical properties of two types of Co-doped ZnO nanostructures: tetrapods and nanofibers grown by a rapid thermal evaporation process and prepared by the electrospinning technique, respectively, were investigated and analyzed. Surface morphology of the samples was examined using scanning electron microscopy. X-ray diffraction measurements showed hexagonal wurtzite crystal structure of both types of investigated nanostructures. Both X-ray diffraction and Raman scattering data confirmed high phase purity of the samples. The magnetic properties studied with the use of the SQUID magnetometer confirmed a presence of ferromagnetic order in analyzed nanostructures. The observed photoluminescence spectra exhibited two groups of lines. The first one, in the ultraviolet spectral range, is due to the optical transitions close to ZnO band gap, the second one in the red region is most probably related to the $Co^{2+}$ d-d internal transitions. The influence of native defects on the optical properties is also shown and discussed. All results reported here lead us to the conclusion that in the mixed crystal nanostructures obtained, a fraction of the $Zn^{2+}$ ions is substituted by $Co^{2+}$ ions.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 868-870
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the clusterization of CdO phase in ZnCdO alloys by modeling fullerene-like Zn₄₄Cd₄O₄₈ cluster
Autorzy:
Ovsiannikova, L.
Kartuzov, V.
Shtepliuk, I.
Lashkarev, G.
Powiązania:
https://bibliotekanauki.pl/articles/1159858.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.55.Et
81.05.Dz
81.07.Bc
Opis:
The structural, cohesive and electronic properties of fullerene-like isolated Zn₄₄Cd₄O₄₈ cluster with consideration of CdO phase clusterization are studied in the frames of density functional theory B3LYP/3-21G(d). It is revealed that an enlargement of CdO phase content in Zn₄₄Cd₄O₄₈ cluster leads to nonlinear rapid increase in cohesive energy and cluster stability, as well as band-gap energy shrinkage.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-41-A-43
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Se Isoelectronic Impurity on the Luminescence Features of the ZnO
Autorzy:
Khomyak, V.
Slyotov, M.
Shtepliuk, I.
Slyotov, O.
Kosolovskiy, V.
Powiązania:
https://bibliotekanauki.pl/articles/1403644.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Bf
81.05.Dz
81.07.Bc
Opis:
Se-doped ZnO films have been deposited on the sapphire substrates by the radio-frequency magnetron sputtering technique. An influence of the isoelectronic impurity Se on the room-temperature luminescence of the ZnO films is studied. It is revealed that the Se doping leads to an appearance of the intense near-band edge emission spectrum, which consists of three emission bands. The dominant emission band is related to the recombination of the bound excitons. The radiation caused by the band-to-band transitions of free carriers is observed in the high-energy side of the spectrum (ħω > $E_{g}$).
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1039-1041
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of ZnO and Zn(Cd)O Fullerene-Like Clusters with a Shell of Diamond-Like Structure with $ \text{sp}^{2}//\text{sp}^{3}$ Bonds
Autorzy:
Ovsiannikova, L.
Powiązania:
https://bibliotekanauki.pl/articles/1399133.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.55.Et
81.05.Dz
81.07.Bc
Opis:
The structural, cohesive, and electronic properties of a fullerene-like $(ZnO)_{60}$ cluster with a shell of diamond-like structure with $\text{sp}^2//\text{sp}^3$ bonds have been investigated in comparison with those of clusters differing in geometry and composed of the equal number of ZnO structural units (clusters of fullerene, onion, and coordination tetrahedron) within the framework of the electron density hybride functional method (B3LYP) with a set of 6-31G(d) split valence basis functions. The fullerene-like $(ZnO)_{60}$ cluster is used as a model in an investigation of the change in the band-gap width (the decrease in the band-gap width is ≈ 0.2 eV) in the case of the substitution of Zn atoms by Cd atoms (20% of substitution) in the ZnO matrix in ZnCdO ternary structures.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 862-864
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Investigation of the Cadmium Effect on Properties of ZnCdO Alloys Using $Zn_{36-x}Cd_{x}O_{36}$ Clusters
Autorzy:
Ovsiannikova, L.
Powiązania:
https://bibliotekanauki.pl/articles/1375895.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.55.Et
81.05.Dz
81.07.Bc
Opis:
The structural, cohesive, and electronic properties of a fullerene-like $Zn_{n-x}Cd_{x}O_{n}$ (n=36) clusters have been investigated within the framework of the electron density hybride functional method (B3LYP) with a set of 3-21G(d) split valence basis functions. These clusters are used as a model in an investigation of the change in the band-gap width in the case of the substitution of Zn atoms by Cd atoms in the ZnO matrix in ZnCdO ternary structures. The presented investigations showed that a substitution of Zn atom to Cd (5.5, 11, 16.7, 22 and 33 at.% Cd) leads to reduction of cluster stability and monotonous decrease of energy gap (0.145, 0.259, 0.354, 0.436, 0.586 eV, accordingly).
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1090-1092
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Properties of ZnO and ZnCdO Nanowires
Autorzy:
Zaleszczyk, W.
Fronc, K.
Aleszkiewicz, M.
Paszkowicz, W.
Wróbel, J.
Dłużewski, P.
Kret, S.
Klepka, M.
Kłopotowski, Ł.
Karczewski, G.
Wojtowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/2047698.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Bf
81.05.Dz
81.07.Bc
Opis:
We report on the photoluminescence studies of ZnO and ZnCdO nanowires grown on SiO$\text{}_{2}$/Si substrates by low-pressure vapor phase synthesis. X-ray diffraction and transmission electron microscopy measurements show that the crystallographic structure of these ZnO and ZnCdO nanowires is of wurtzite-type with a high crystal perfection. Surface morphology of samples was determined by scanning electron microscopy and atomic force microscopy. The photoluminescence spectra of as-grown nanowires, nanowires extracted from the substrate and deposited onto Si wafer, and nanowires dispersed in ethanol by sonication were investigated at room temperature and compared to each other. The temperature dependence of the near band-gap photoluminescence emitted by the as-grown nanowires was also measured and analyzed.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 357-362
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Elaboration Conditions on the Structural, Morphological and Luminescence Properties of ZnO Nanopowders
Autorzy:
Arab, L.
Guergouri, K.
Powiązania:
https://bibliotekanauki.pl/articles/1401219.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
81.07.Wx
81.20.Fw
07.57.Ty
78.55.Qr
68.37.Hk
Opis:
Pure ZnO nanopowders were synthesized by the sol-gel method, which has several advantages, among which we include, achieving low temperature deposition and synthesis of new hybrid organo-mineral materials. The effect of the elaboration conditions (the elaboration concentrations ratio of precursors $(C_{Z}//C_{A})$, the gelling temperature $(T_g)$ and the gelling time $(t_g)$) on the structural, morphological and luminescence properties of ZnO nanopowders has been investigated. The chemical composition of the powders, determined by FTIR spectroscopy, indicate the exclusive presence of Zn-O bonds, as it is shown by the XRD spectra. The XRD results indicate also that the synthesized ZnO powder is a solid solution, crystallizing in pure würtzite structure with a minimum grain size of about 23 nm for the powders prepared using: $C_{Z}//C_{A}$=0.06%, $T_g$=130°C and $T_g$=4 h. The morphological aspect, given by the SEM images, revealed that the powders are made of sheets, consisting of small particles agglomerated together. The photoluminescence study of the ZnO powders shows spectra with luminescence peaks from green to ultraviolet light, the more intensive emission is connected to the peaks of the blue luminescence.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 940-942
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of ZnSe Nanolayers by Spectroscopic Ellipsometry
Autorzy:
Šćepanović, M.
Grujić-Brojčin, M.
Nesheva, D.
Levi, Z.
Bineva, I.
Popović, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1795712.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
81.15.-z
81.05.Dz
78.30.-j
07.60.Fs
68.55.-a
Opis:
Single layers of ZnSe with thicknesses of 30, 40, 50, 70 and 100 nm are deposited at room substrate temperature by thermal evaporation of ZnSe powder in vacuum. The layers surface morphology has been investigated by atomic force microscopy. Structural characterization by the Raman scattering measurement revealed the existence of randomly oriented crystalline ZnSe particles in all layers, and the presence of amorphous phase in layers thinner than 100 nm. The ellipsometric measurements were performed in the range from 1.5 to 5 eV at room temperature in air. To interpret the experimental results, the Bruggeman effective medium approximation of dielectric function of ZnSe layers has been used, representing the layers as different mixtures of crystalline ZnSe (c-ZnSe), amorphous ZnSe (a-ZnSe), and voids. The assumption of polycrystalline ZnSe layers modeled as mixture of porous c-ZnSe (with volume fraction of voids ≈ 0.17) and a-ZnSe gives the best fit of ellipsometric experimental data. Single layer thicknesses similar to those expected from preparation conditions have been obtained by this fitting procedure. It has been also found that decrease in the layer thickness causes an increase of the volume fraction of a-ZnSe. Thus, c-ZnSe/a-ZnSe ratio, porosity and layer thickness obtained by spectroscopic ellipsometry, provides useful information about crystallinity and micro-/nanostructure of ZnSe nanolayers.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 708-711
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanostructured ZnO Photoelectrode Synthesis for Dye Sensitized Solar Cells
Autorzy:
Gültekin, D.
Alaf, M.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1182877.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
61.46.Df
81.07.Wx
81.20.Fw
88.40.jm
Opis:
The main aims of this work were to produce and examine the characteristics of nanostructured ZnO in dye-sensitized solar cells. Parameters which are affected by the efficiency such as precursor materials, morphology were investigated. The Raman spectroscopy was used to investigate transformation from bulk material to solution. General morphologies and detailed structural characterizations were obtained using field emission scanning electron microscopy. X-ray diffractometer has been used to determine preferred crystal orientation and particle size of the ZnO nanostructures.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 301-303
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of ZnO Nanopowders and ZnO-CNT Nanocomposites Prepared by Chemical Precipitation Route
Autorzy:
Gültekin, D.
Alaf, M.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399778.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
81.07.Wx
81.05.Dz
61.48.De
81.20.Fw
Opis:
The aims of this work are synthesis of ZnO nanopowders and producing nanocomposites by mixing with carbon nanotubes. ZnO nanopowders have been synthesized by chemical precipitation route. Different amount of collected nanosized Zn-based precipitates and chemically oxidized carbon nanotubes powder have been mix together and annealed at 400°C. Characterization of produced nanopowders and nanocomposites have been carried out by X-ray diffractometer and scanning electron microscope.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 274-276
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AFM/STM Modification of Thin Sb Films on 6H-SiC(0001)
Autorzy:
Mazur, P.
Zuber, S.
Grodzicki, M.
Ciszewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1195467.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
68.37.Ps
68.37.Ef
68.37.-d
81.10.Bk
81.07.-b
Opis:
Atomic force microscopy and scanning tunneling microscopy have been used for nanometer scale modifications of Sb films deposited on 6H-SiC(0001) surface. The films are grown in situ by vapor deposition under ultrahigh vacuum. The growth follows the Volmer-Weber mode. Ultrathin (up to 3 nm on average) Sb films which consist of no coalesced islands can be modified by moving the island over the substrate surface by the AFM tip. Thicker films, which are firmer due to the coalescence, can be modified by the field and/or current produced by STM tip. Final result of the modifications is adsorbate free 6H-SiC(0001) surface restitution over the modified area.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1131-1133
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sb Layers on p-GaN: UPS, XPS and LEED Study
Autorzy:
Grodzicki, M.
Mazur, P.
Pers, J.
Zuber, S.
Ciszewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1376064.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
68.37.Ps
68.37.Ef
68.37.-d
81.10.Bk
81.07.-b
Opis:
The electronic structure of p-type GaN(0001) surfaces and its modification by antimony adsorption, and properties of Sb/GaN(0001) interface, are presented in this report. The studies were carried out in situ by ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and low-energy electron diffraction. Thin Sb layers were deposited under ultrahigh vacuum conditions onto the substrate at room temperature. Electron affinity of clean p-GaN surface amounted to 3.0 eV. A small amount of Sb on GaN(0001) surface reduced the electron affinity to 1.9 eV. The work function of the Sb layer was equal to 4.4 eV. For the Schottky barrier height of the Sb/GaN interface, the value of 2.50 eV was obtained.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1128-1130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epidermal Layers Characterisation by Opto-Magnetic Spectroscopy Based on Digital Image of Skin
Autorzy:
Koruga, Đ.
Bandić, J.
Janjić, G.
Lalović, Č.
Munćan, J.
Dobrosavljević Vukojević, D.
Powiązania:
https://bibliotekanauki.pl/articles/1489823.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.58.Bh
07.05.Pj
42.79.-e
42.30.-d
42.25.Ja
87.64.Dz
Opis:
According to the most literature data, the skin is usually observed as a simple structure with equivalent electrical model, which includes general properties of epidermis, basal membrane and dermis. In this paper, we analyzed the skin structure as a more complex system. Particularly we analyzed epidermis based on layers approach and its water organization in lipids ordered in sub-layers. Using opto-magnetic spectroscopy method, which is very sensitive to paramagnetic/diamagnetic properties of the tissue, we found out that nanowater structure ordering in lipids of epidermal layers play very important role in skin properties. We use bioimpedance as complementary and compatible method to opto-magnetic spectroscopy in skin characterization. In our investigation we found out the difference of the skin properties of the people who are drinking two different type of water (Z and N). We observed the significant difference in middle part of stratum granulosum, where water-lipid sub-layers exists. These results indicate importance of water nanolayers presence in epidermis and type of drinking water reflecting on human skin properties.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 606-610
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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