Temat: 61.46.Hk - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Effect of Annealing Time on Structure of $Fe_{72.5}Cu_{1}Nb_{2}Mo_{2}Si_{15.5}B_{7}$ Alloy
Autorzy:: Nemcová, V.
Girman, V.
Hrabčáková, V.
Michalik, Š.
Bednarčík, J.
Almáši, M.
Sovák, P.
Tematy:: 61.05.cp
61.46.Hk
61.05.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1367403.pdf Link otwiera się w nowym oknie
Opis:: The process of a primary crystallization of the $Fe_{72.5}Cu_{1}Nb_{2}Mo_{2}Si_{15.5}B_{7}$ alloys was investigated by differential thermal analysis (DTA), x-ray diffraction (XRD) and transmission electron microscopy (TEM). Amorphous ribbons were isothermally annealed for 0.5, 2, 6, 30 and 150 minutes at 520 °C. Both, the XRD and TEM study showed that the level of devitrification of the sample increases with the annealing time. The above mentioned techniques confirmed the presence of the nanocrystalline grains of the $Fe_{3}Si$ phase and enable us to study the evolution of the identified phase.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Hydroquinone Synthesis of Silver Nanoparticles from Silver Bromide Suspensions
Autorzy:: Król-Gracz, A.
Nowak, P.
Michalak, E.
Dyonizy, A.
Tematy:: 81.07.-Bc
61.46.Hk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1491287.pdf Link otwiera się w nowym oknie
Opis:: The results of research into the preparation of silver nanoparticles using photoreduction in the presence of hydroquinone as the reductant were discussed. Substrates for the synthesis of silver nanoparticles were ultrafine crystalline gelatine-stabilised aqueous suspensions of silver bromide. The influence of the reductant to substrate molar ratio and the medium's pH to the efficient production of silver nanoparticles were studied. The properties of resultant silver particles were examined using UV-Vis spectroscopy. Transmission electron microscopy was used for the photomicrography of silver nanoparticles suspensions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of Zn on Structure and Magnetic Properties of Rapid Quenched (Fe-Zn)-Cu-Nb-Si-B Alloys
Autorzy:: Kolesar, V.
Michalik, S.
Kovac, J.
Girman, V.
Sovak, P.
Kollar, P.
Tematy:: 61.46.Hk
75.50.Bb
75.75.Cd; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1533958.pdf Link otwiera się w nowym oknie
Opis:: The aim of this work was to study the influence of Zn on the formation of nanostructure in $Fe_{73.5 - x}Zn_xCu_1Nb_3Si_{13.5}B_9$ (x = 1, 3, 5) ribbons prepared by the melt-spinning technique. X-ray diffraction measurements proved amorphous state of the sample with x = 1. The sample with x = 3 contains a small fraction of Fe_3Si phase and the sample with x = 5 is in nanocrystalline state with the average grain size of about 25 nm. The reduced radial distribution function G(r) was calculated for local structure investigation. Increasing Zn content enhances crystallization during solidification which leads to increase of magnetocrystalline anisotropy and consequently to increase of coercivity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Defects in Zirconia Nanomaterials Doped with Rare-Earth Oxides
Autorzy:: Prochazka, I.
Cizek, J.
Melikhova, O.
Konstantinova, T.
Danilenko, I.
Tematy:: 81.07.Wx
61.46.Hk
78.70.Bj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1338541.pdf Link otwiera się w nowym oknie
Opis:: Positron lifetime and coincidence Doppler broadening measurements on $ZrO_2$+3 mol.% $RE_2O_3$ (RE = Eu, Gd, Lu) nanopowders and ceramics obtained by sintering these nanopowders are reported. The initial nanopowders were prepared by a co-precipitation technique and exhibited a mean particle size of ≈ 15 nm. The nanopowders were calcined and pressure-compacted. All compacted nanopowders exhibited the prevailing tetragonal phase with at most 15% of the monoclinic admixture. Positrons in compacted nanopowders were found to annihilate almost exclusively at grain boundaries: (i) vacancy-like misfit defects along grain boundaries and (ii) larger defects situated at intersections of grain boundaries (triple points). In nanopowders, a small portion of positrons formed positronium in pores between crystallites. Sintering of nanopowders at 1500C caused a substantial grain growth and formation of ceramics. Sintering-induced grain growth led to a disappearance of the triple points and pores. The ceramics containing Eu and Gd dopants consist of mixture of the monoclinic and the tetragonal phase, while the ceramics with Lu dopant exhibits almost exclusively the tetragonal phase.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Optical and Structural Properties of Cu Doped ZnS Nanocrystals: Effect of Temperature and Concentration of Capping Agent
Autorzy:: Hasanzadeh, J.
Tematy:: 61.46.-w
61.46.Hk
78.67.Bf
78.67.Hc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1398921.pdf Link otwiera się w nowym oknie
Opis:: We have provided the Cu doped zinc sulfide (ZnS:Cu) nanoparticles using a wet chemical synthesis. In principle, the nanoparticles are provided by mixing the reactants in a double distilled water solvent. We have used the mercaptopropionic acid as the capping agent. We have obtained the physical properties of the nanoparticles using the methods: UV absorption, photoluminescence spectroscopy, and X-ray diffraction analysis. The average size of nanoparticles is obtained in the range 3-6 nm. In addition, the X-ray diffraction pattern of ZnS:Cu nanoparticles reveals a zinc-blende crystal structure at room temperature.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: Microstructure and Surface Morphology of Nanocrystalline Silver Silicates
Autorzy:: Duhan, S.
Tematy:: 61.46.Df
61.46.Hk
78.67.Bf; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1489860.pdf Link otwiera się w nowym oknie
Opis:: Microstructure and surface morphology of AgO nanocrystallites (25 nm) supported on $SiO_2$ and subjected to heat treatment in air up to 500C have been studied by transmission electron microscopy, scanning electron microscopy, and the Fourier transform infrared spectroscopy measurements. It has been found that heating at 500C resulted in spreading of AgO over silica and formation of quasi two-dimensional amorphous phase (silicate precursor) exhibiting very weak band at $566 cm^{-1}$ have appeared in the Fourier transform infrared spectroscopy. Nanocrystalline silver silicate of undefined structure formed at 300-500C.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Surface Chemistry of Zirconia Nanopowders Doped with $Pr_2O_3$: an XPS Study
Autorzy:: Suchorski, Y.
Wrobel, R.
Becker, S.
Opalińska, A.
Narkiewicz, U.
Podsiadly, M.
Weiss, H.
Tematy:: 79.60.-i
61.46.-w
61.46.Hk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1811498.pdf Link otwiera się w nowym oknie
Opis:: Zirconia nanopowders of tetragonal crystallographic structure doped with $Pr_2O_3$ were prepared by the microwave-assisted hydrothermal synthesis and coprecipitation method. The surface compositions were studied by X-ray photoelectron spectroscopy. The nanopowder particles appear to be inhomogeneous in their structure: for the surface region an enrichment with praseodymium is detected by X-ray photoelectron spectroscopy measurements. This allows the assumption of a core-shell-like structure of single nanopowders particles. The X-ray photoelectron spectroscopy studies confirm also $Zr^{4+}$ and $Pr^{3+}$ as main oxidation states of zirconium and praseodymium in the studied compounds.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Influence of Temperature and Time on $Nd_2O_3-SiO_2$ Composite Prepared by the Solgel Process
Autorzy:: Duhan, S.
Aghamkar, P.
Tematy:: 61.46.Df
61.46.Hk
78.67.Bf; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1812356.pdf Link otwiera się w nowym oknie
Opis:: Using solgel method $Nd_2O_3-SiO_2$ binary oxide systems were prepared. The binary oxide transformed from the amorphous phase to nanocrystalline phase upon heat treatment in air. Characterization of the $Nd_2O_3-SiO_2$ was carried out by using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The effect of the sintering temperature and time on the evolution of the binary oxide system was discussed. It is found that sintering time plays a pivotal role to obtain $Nd_2O_3-SiO_2$ nanocomposite. At temperature of 900°C, the sample was sintered for 12 h and monoclinic $Nd_2O_3$ nanocrystallites, with average crystallite size ≈12 nm, were obtained.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Microstructural Study of Fe-Si(Ge)-Nb-Cu-B Finemet Alloys
Autorzy:: Michalik, S.
Bednarcik, J.
Brzózka, K.
Sovak, P.
Górka, B.
Tematy:: 61.05.cp
61.05.C-
61.46.Hk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1534048.pdf Link otwiera się w nowym oknie
Opis:: Structural changes in Finemet based alloys invoked by germanium replacement for silicon were investigated using the X-ray diffraction, the X-ray absorption spectroscopy and the Mössbauer spectroscopy. Ge substitution preserves a nanostructural character of annealed samples at temperature 550°C; specifically the formation of a $DO_3$-type with about 19 at.% of (Si,Ge) was confirmed. The mean size of nanocrystals was estimated to be about 7 nm.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The Effect of Carbon Coating on the Electrochemical Performance of Nanosized $Li_2FeSiO_4$ Cathode Materials
Autorzy:: Wang, Y.
Su, D.
Wang, G.
Tematy:: 61.05.cp
61.46.Hk
68.37.-d; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399781.pdf Link otwiera się w nowym oknie
Opis:: Carbon-coated $Li_2FeSiO_4//C$ cathode materials have been synthesized through a modified ball-milling process. The physical characterizations of $Li_2FeSiO_4$ were conducted by using X-ray powder diffraction, field-emission scanning electron microscopy and transmission electron microscopy techniques. Field-emission scanning electron microscopy and transmission electron microscopy images revealed that $Li_2FeSiO_4//C$ consists of nanosized particles coated with an amorphous carbon layer. The electrochemical performances of $Li_2FeSiO_4//C$ cathode materials were evaluated through fully assembled lithium batteries via cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy. The $Li_2FeSiO_4//C$ cathode materials showed a much improved electrochemical performance in terms of higher specific capacity, better cycling performance and less charge transfer resistance than that of the pristine $Li_2FeSiO_4$.
Dostawca treści:: Biblioteka Nauki

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