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Wyszukujesz frazę "81.15.Gh" wg kryterium: Temat


Tytuł:
Nanostructure features, phase relationships and thermoelectric properties of melt-spun and spark-plasma-sintered skutterudites
Autorzy:
Kogut, Iu.
Nichkalo, S.
Ohorodniichuk, V.
Dauscher, A.
Candolfi, C.
Masschelein, P.
Jacquot, A.
Lenoir, B.
Powiązania:
https://bibliotekanauki.pl/articles/1052685.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Eb
72.15.Jf
72.20.Pa
66.70.Df
81.20.Ev
81.16.-c
81.40.Gh
Opis:
Reduction of thermal conductivity remains a main approach relevant to enhancement of figure-of-merit of most thermoelectric materials. Melt spinning combined with spark plasma sintering appears to be a vital route towards fine-grain skutterudites with improved thermoelectric performance. However, upon high-temperature processing the Fe_{4-x}Co_{x}Sb_{12}-based skutterudites are prone to decompose into multiple phases, which deteriorate their thermoelectric performance. In this study we addressed the effects of combined melt spinning and spark plasma sintering on the phase composition and microstructural properties of filled Fe_{4-x}Co_{x}Sb_{12} as well as their influence on thermoelectric characteristics of these compounds. The crystallites of filled Fe_{4-x}Co_{x}Sb_{12} were effectively reduced to sizes below 100 nm upon melt spinning, but also severe decomposition with weakly preserved nominal phase was observed. Spark plasma sintering of melt spun skutterudites resulted in even further reduction of crystallites. Upon short annealing and sintering the n-type materials easily restored into single-phase filled CoSb₃ with nanoscale features preserved, while secondary phases of FeSb₂ and Sb remained in p-type compounds. Relatively high figure-of-merit ZT_{max} of 0.9 at T ≈ 400°C has been gained in nanostructured Yb_{x}Co₄Sb_{12}, however, no significant reduction of thermal conductivity was observed. Abundant impurities in p-type filled Fe_{4-x}Co_{x}Sb_{12} led to drastic drop in their ZT, which even further degraded upon thermal cycling.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 879-883
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Studies of C-Ni-Pd Nanocomposite Films Deposited on Al₂O₃ Substrate
Autorzy:
Kozłowski, M.
Czerwosz, E.
Sobczak, K.
Kurowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1032987.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.23.Pq
81.07.Bc
81.15.Gh
82.45.Mp
Opis:
The properties of nanocomposite carbon-nickel-palladium (C-Ni-Pd) films deposited on Al₂O₃ substrate have been investigated and the results are presented in this work. C-Ni-Pd films were obtained by a 3 step process consisting of PVD/CVD/PVD methods. The structure and morphology of the obtained films were characterized by scanning electron microscopy and transmission electron microscopy techniques at various stages of film formation. Energy dispersive X-ray spectrometer was used for measuring the elements segregation in the obtained film. Transmission electron microscopy and scanning transmission electron microscopy observations have shown carbon nanotubes decorated with palladium nanoparticles in the final film. The average size of the palladium nanoparticles did not exceed 10 nm.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1409-1412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Substrate on Size of Pd Nanoparticles in C-Pd Composites Obtained in the PVD and CVD Processes
Autorzy:
Sobczak, K.
Kozłowski, M.
Czerwosz, E.
Powiązania:
https://bibliotekanauki.pl/articles/1032958.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.23.Pq
81.07.Bc
81.15.Gh
82.45.Mp
Opis:
This paper presents the results of research of C-Pd composite films obtained by the physical vapor deposition and chemical vapor deposition method. These films will be applied as hydrogen sensors. It has been examined whether the substrate has an impact on morphology and topologies of the C-Pd composite and whether the thermal conductivity of the substrate has an impact on the average size of the Pd nanoparticles. Substrates such as Al₂O₃, SiO₂, Si, and Mo were used, and in the physical vapor deposition process fullerene (C₆₀) and palladium acetate were deposited. Some of the samples were examined microscopically, while another part was modified in the chemical vapor deposition process in the presence of xylene. It was found that the average size of the Pd nanoparticles prepared in the physical vapor deposition process is independent of the substrate for all of the substrates used in the present experiment. During the chemical vapor deposition process an increase of the size of the Pd nanoparticles was observed - as expected. What is more, we noticed a weak relation between the size of the Pd nanoparticles and the type of substrate on which the C-Pd composite was deposited.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1413-1416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of carbon nanomaterials over Ni/ZSM-5 catalyst using simplex method algorithm
Autorzy:
Majewska, J.
Michalkiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1075535.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.De
81.16.Hc
81.15.Gh
Opis:
Carbon nanomaterials were prepared from methane by catalytic decomposition over a nickel-supported ZSM-5 catalyst. The mole ratio of SiO₂ to Al₂O₃ in ZSM-5 was 200-400. The nickel content was varied from 17 to 23 wt% Ni. In order to find the greatest yield and the highest quality of carbon nanomaterials the simplex design method for planning the experiments was applied. Different parameters such as: temperature, methane flow, nitrogen flow and nickel content in the catalyst were evaluated. The carbon nanomaterials were analyzed by the Raman spectroscopy, scanning and transmission electron microscopy, and total organic carbon analyzer.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 153-157
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and optical properties of boron nitride grown by MOVPE
Autorzy:
Dąbrowska, A.
Pakuła, K.
Bożek, R.
Rousset, J.
Ziółkowska, D.
Gołasa, K.
Korona, K.
Wysmołek, A.
Stępniewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1160531.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
78.30.Fs
78.20.-e
Opis:
Boron nitride layers were grown on sapphire substrate by metal organic vapor phase epitaxy system that was originally designed for growth of GaN. Structures were characterized by scanning electron microscopy, atomic force microscopy, the Raman spectroscopy, absorption and time resolved photoluminescence. Presented results confirm successful deposition of BN layers and gives information about basic properties of the material. The Raman line at 1370 cm^{-1} and absorption edges at 5.6-5.9 eV were observed which is related to hexagonal phase.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-129-A-131
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Comparative Study of the Structure and Phase Composition of Ni-Based Coatings Modified by Plasma Jet or Electron Beam
Autorzy:
Alontseva, D.
Russakova, A.
Krasavin, A.
Powiązania:
https://bibliotekanauki.pl/articles/1398796.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.-z
81.07.-b
68.47.Gh
Opis:
The paper deals with the results of the comparative study into the structure and phase composition, as well as some properties (microhardness, corrosion resistance) of Ni-based powder coatings before and after their modification by DC electron beam or DC pulse plasma jet, according to the modes recommended on the basis of model calculations of the temperature profiles at irradiation. The transmission electron microscopy and X-ray analysis have revealed that irradiation leads to an increase in the volume fraction of reinforcing nanosized intermetallic components in the coatings. There were established certain similarities and differences in the structure and properties of the coatings modified by different types of irradiation. The microhardness of the irradiated coatings has increased in both cases along with the growth of the volume fraction of the CrNi₃ particle phase. However, it was found that the diffusion zone in the coatings modified by plasma jet is higher than that of the coatings modified by electron irradiation. The coating surface melted by the electron beam has a marked reduction of its roughness and better homogenization of the microstructure therefore demonstrating better adhesion and corrosion resistance.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 838-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Metalorganic Vapour Phase Epitaxy Growth of A^{III}B^{V} Heterostructures Observed by Reflection Anisotropy Spectroscopy
Autorzy:
Zíková, M.
Hospodková, A.
Pangrác, J.
Vyskočil, J.
Hulicius, E.
Oswald, J.
Komninou, P.
Kioseoglou, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398563.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
81.07.Ta
78.67.Hc
78.55.Cr
Opis:
Reflectance anisotropy spectroscopy is a useful technique used for in situ observation of the metalorganic vapour phase epitaxy growth, because it does not require vacuum in the reaction chamber. With this method we are able to observe the quantum dot growth, the incorporation of indium or antimony atoms in the layer or the monolayer growth of GaAs. We can also estimate the amount of InAs needed for the quantum dot formation, the time necessary for the quantum dot growth or reveal the unintended growth of InAs quantum dots from large dissolved InAs objects.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-75-A-78
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystalline CVD Diamond Coatings on Fused Silica Optical Fibres: Optical Properties Study
Autorzy:
Ficek, M.
Bogdanowicz, R.
Ryl, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402648.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
81.05.ug
82.80.Gk
68.55.A-
78.66.Qn
Opis:
Seeding and growth processes of thin diamond films on fused silica optical fibres have been investigated. Glass pre-treatment by dip coating in two detonation nanodiamond (DND) seeding media has been studied. The DND suspension in ethyl alcohol and dispersion of DND in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) were chosen for the seeding purpose. The grain size distribution of nanodiamond particles in both seeding media was kept at the same level (approximately 10-50 nm). After the seeding nanocrystalline diamond films were deposited on the fibres using microwave plasma assisted chemical vapour deposition system. The results of the process were investigated using numerical analysis of scanning electron microscopy images. The molecular structure of diamond has been examined with micro-Raman spectroscopy. Thickness, roughness and optical properties of the nanocrystalline diamond films in VIS-NIR wavelength range were investigated on reference samples using spectroscopic ellipsometry. Light reflection at the fibre end-face for different deposition parameters was also investigated. Proposed seeding method can be further effectively applied for manufacturing of optical fibre sensors. Due to extraordinary properties of diamond, which include high chemical and mechanical resistance, such films are highly desired for optical sensing purposes.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 868-873
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Polycrystalline CVD Diamond Seeding with the Use of sp³/sp² Raman Band Ratio
Autorzy:
Golunski, L.
Sobaszek, M.
Gardas, M.
Gnyba, M.
Bogdanowicz, R.
Ficek, M.
Plotka, P.
Powiązania:
https://bibliotekanauki.pl/articles/1402345.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
81.05.ug
82.80.Gk
68.55.A-
Opis:
The influence of various nanodiamond colloids used for seeding nondiamond substrates in microwave plasma enhanced chemical vapour deposition diamond process was investigated. Colloids based on deionized water, isopropanol alcohol and dimethyl sulfoxide (DMSO) were used with different grain size dispersion: 150, 400 and 35 nm, respectively. The influence of growth time was also taken into consideration and bias enhanced nucleation. Microcrystalline diamond films were deposited on the seeded substrates in microwave plasma chemical vapour deposition using hydrogen-methane gas mixture. Seeding efficiency was investigated by means of scanning electron microscopy and Raman spectroscopy. Authors defined the new factor called as diamond ideality factor (di) which can give a quick estimation of quality of film and relative sp³ content. Few main peaks were identified at the following wave numbers: diamond sp³ peak 1332 $cm^{-1}$, D band peak 1355 $cm^{-1}$, C-H bending peak 1440-1480 $cm^{-1}$ and G band peak 1560 $cm^{-1}$. The best di was achieved for DMSO based colloid in all cases. The application of bias enhanced nucleation increases the diamond crystals size and the sp³/sp² ratio.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 136-140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-Rays Response of Diamond Detectors Constructed Using Diamond Layers Produced by Low Power Microwave Chemical Vapor Deposition Reactor
Autorzy:
Kordyasz, A.
Bednarek, A.
Kowalczyk, M.
Tarasiuk, J.
Kulczycka, E.
Teodorczyk, M.
Gajewski, M.
Kordyasz, Ł.
Rowiński, O.
Lamparski, K.
Karwański, Ł.
Lipczewski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402641.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.75.-d
81.15.Gh
29.40.Vj
07.85.Fv
Opis:
The low power reactor for microwave chemical vapor deposition process is described. The rotating Mo holder of 12 mm diameter and 6 mm height with the diamond substrate was heated by 2.45 GHz microwaves to temperature about 800°C in the range of (1.5-7)% $CH_{4}//H_{2}$ mixture to create plasma at pressure 70 Tr. Stabilization of the holder temperature was performed by optical observation of radiation from the holder followed by adjusting of the magnetron power. Diamond detectors are produced using microwave chemical vapor deposition process grown on single crystal diamond high pressure high temperature Sumimoto substrates, [100] oriented. The response of diamond detectors for X-rays has been measured in the current mode using medical X-rays tube. The linear response of the diamond detector current versus X-ray tube current (dose) is presented.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1555-1559
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
YIG Film for Magnetic Field Sensor
Autorzy:
Kaya, A.
Atalay, S.
Gencer, H.
Kaya, O.
Kolat, V.
Izgi, T.
Powiązania:
https://bibliotekanauki.pl/articles/1401218.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
84.40.Az
75.30.Ds
41.20.Jb
85.75.Ss
Opis:
Single crystal $Y_3Fe_5O_{12}$ (YIG) film was grown onto (111) oriented gadolinium gallium garnet (GGG) substrate by the liquid phase epitaxy (PLD) technique. The X-ray diffraction measurements showed that epitaxial growth of the film along its (111) axis. The surface characteristic was investigated by atomic force microscopy (AFM) measurement. The magnetic field sensor consisted of a rectangular shape with 5 mm wide, 15 mm long and 5 μm thick YIG film and a pair of identical 50 μm wide microstrip copper transducers elements separated by 6 mm. The filter was tested by measuring reflection $S_{11}$ characteristic at various bias magnetic fields. The results have showed that when the bias field increased from 0 to 2.5 kOe, the frequency value corresponding to $S_{11}$ maxima increased from 1 GHz to 9 GHz. This suggests that the wide range magnetic field sensing and the highly sensitive field sensing are simultaneously fulfilled with the YIG film.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 937-939
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermo-Optical Parameters of Amorphous a-C:N:H Layers
Autorzy:
Pieczyńska, E.
Jaglarz, J.
Marszalek, K.
Tkacz-Śmiech, K.
Powiązania:
https://bibliotekanauki.pl/articles/1377543.pdf
Data publikacji:
2014-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.60.Fs
78.20.-e
78.20.Ci
78.20.N-
78.30.Ly
81.05.U-
81.15.Gh
Opis:
Thermo-optical properties of hydrogenated amorphous carbon nitride layers (a-C:N:H) deposited on crystalline silicon by plasma assisted chemical vapour deposition were studied. The layers were characterized by the Fourier transform infrared spectroscopy and their chemical composition, i.e. [N]/[C] ratio, was determined by energy dispersive X-ray technique. The optic measurements were made by spectroscopic ellipsometer Wollam M2000 equipped with a heated vacuum chamber. The measurements of ellipsometric angles were carried out during heating the sample from room temperature to 300°C. Refractive index, extinction coefficient and the layer thicknesses were calculated by fitting the model of the layer to the ellipsometric data. The results confirm that at about 23°C the layer properties are changed. The measured thermo-optical parameters, dn/dT and dk/dT, show abrupt change from negative to positive values which can be explained by structure graphitization. Simultaneously, the bandgap decreases from 2.5 to 0.7 eV and the layer thickness drops to about 50% of the initial value.
Źródło:
Acta Physica Polonica A; 2014, 126, 6; 1241-1245
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ellipsometric Evaluation of the Optical Constants of Zirconium Oxynitride Thin Films Deposited by Reactive Pulsed Magnetron Sputtering
Autorzy:
Tomsah, I.
Powiązania:
https://bibliotekanauki.pl/articles/1400496.pdf
Data publikacji:
2013-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
61.05.C-
78.66.-w
Opis:
Three different zirconium oxynitride films were deposited onto glass and Si (100) substrates at room temperature by pulsed reactive dc magnetron sputtering of a metallic Zr target in an $Ar//O_2//N_2$ atmosphere. The structural, compositional and optical properties of the deposited films were found to depend on the ratio of nitrogen partial pressure to the total reactive gas partial pressure. Energy-dispersive X-ray spectroscopy measurements revealed that as the nitrogen amount increased in the reactive gas the nitrogen content was found to increase in the film. The film structure was determined by X-ray diffraction. The X-ray diffraction patterns of the analyzed samples revealed a strong dependence of the $ZrO_xN_{y}$ film structure on composition. A two layer model, the Bruggeman effective medium approximation and both Drude absorption edge and Lorentz oscillators were used to describe the surface roughness layer and the main $ZnO_xN_{y}$ layer, respectively, was used to describe the experimental ellipsometric data. The optical band gap was decreased from 3.56 to 3.45 eV with changing nitrogen content, while refractive index at 650 nm simultaneously was increased from 1.98 to 2.11.
Źródło:
Acta Physica Polonica A; 2013, 124, 1; 141-145
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of Ni-Based Plasma Detonation Coatings by a Low-Energy DC E-Beam
Autorzy:
Alontseva, D.
Krasavin, A.
Pogrebnjak, A.
Russakova, A.
Powiązania:
https://bibliotekanauki.pl/articles/1400454.pdf
Data publikacji:
2013-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.-z
81.07.-b
68.47.Gh
Opis:
The paper presents the study of Ni-based coatings deposited by plasma detonation onto a steel substrate after direct current low-energy electron beam irradiation and proposes explicit parameters of the electron beam for modification of coatings by irradiation. The choice of irradiation modes is based on the calculation of the temperature profile in the Ni-Fe two-layer absorbents using numerical simulation methods. It was found that the exposure of coatings to irradiation according to the recommended modes leads to the evolution of the structural-phase state of coatings and substantial improvement of performance properties of modified surfaces. The wear resistance of modified surfaces increases 3 times, the microhardness increases on the average 25%.
Źródło:
Acta Physica Polonica A; 2013, 123, 5; 867-870
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water Vapor-Plasma-Enhanced Oxidation of Thin Titanium Films
Autorzy:
Pranevicius, L.
Tuckute, S.
Gedvilas, K.
Powiązania:
https://bibliotekanauki.pl/articles/1400471.pdf
Data publikacji:
2013-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Cd
68.47.Gh
81.65.Mq
66.30.jj
Opis:
It is shown that the water vapor plasma processing offers modified Ti oxidation thermodynamics and kinetics over conventional, thermal oxidation. The 0.3-0.6 μm thick Ti films were sputter-deposited on silicon substrates and subsequently treated with low-pressure water vapor plasma at room temperature under continuous injection of water cloud vapor into the vacuum chamber from the heated water container. The changes of microstructure, phase composition, elemental composition and surface morphology upon the RF-power dissipated in plasma and treatment duration were investigated. We conclude that oxygen diffusion is enhanced in the presence of water vapor plasma, and deduce that fast $H^+$ transients because of their high mobility may be responsible for oxygen diffusion enhancement. This phenomenon can be explained as the result of two coexisting and competing reactions of oxidation and reduction on the surface. The different plasma reduction/oxidation state on the surface can be maintained by coordinated adjustment of an intensity of plasma radiation. Analysis of the experimental results is used to obtain important insights into the behavior of water molecules adsorbed on the oxidized titanium surfaces exposed to water vapor plasma at room temperature.
Źródło:
Acta Physica Polonica A; 2013, 123, 5; 907-910
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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