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Excimer Laser-Induced CVD of Carbon Encapsulated Cobalt Nanoparticles
Fajgar, Radek ; Maryško, Miroslav ; Dřínek, Vladislav ; Kupčík, Jaroslav ; Šubrt, Jan
Decomposition of acetylene / Co(CO)(3)(NO)mixtures induced by excimer ArF laser pulses is an efficient technique for preparation of amorphous cobalt nanoparticles encapsulated in carbon. Vacuum heating up to 900 degrees C leads to crystallization the metal core. The cobalt core crystallizes in a face-centered cubic (beta) form as revealed by X-ray and electron diffraction techniques and carbon affords graphite outer part. Properties of the Co(core) - carbon(shell)nanocomposites were examined by spectroscopy and microscopy techniques. Magnetization studies revealed paramagnetic behavior of the as-prepared amorphous deposit and superparamagnetic behavior of the annealed samples.
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Synthesis of Lead and Lead Oxide Nanoparticles for Inhalation Experiments
Moravec, Pavel ; Smolík, Jiří ; Ondráček, Jakub ; Vodička, Petr ; Fajgar, Radek
From the three tested methods of NP's generation the evaporation/condensation of metallic Pb seems to be the most suitable for long lasting inhalation experiments due to its simplicity, unambiguous mechanism of NP′s formation and well defined composition. Nevertheless, NP′s can change their composition, at least on the surface layer, during the time-lag between their formation and inhalation. Thermal decomposition of PbTHD2 can produce sufficiently high concentration of NP′s but there is some uncertainty about their composition due to presence of OC in NP′s. Oxidation of PbTHD2 produces carbon free NP′s, but the number concentration of NP′s is somewhat low.
Plný tet: SKMBT_C22013101814595 -  PDF
Plný text: content.csg - PDF
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Generation of Pb/PbOx Nanoparticles for Inhalation Experiments
Moravec, Pavel ; Smolík, Jiří ; Ondráček, Jakub ; Vodička, Petr ; Fajgar, Radek
Health aspects of nanoparticles (NP′s) on living beings are considered to be important. However, the real data of the impact of NP′s inhalation are rather rare. A study of allocation of MnOx nanoparticles in organs of laboratory animals in inhalation chamber was presented by Večeřa and Mikuška (2012). For these experiments a source of continual generation of nanoparticles in duration of days or even weeks and in appropriate concentration is necessary. In this work a study of continual generation of Pb/PbOx nanoparticles in hot wall tube reactor are presented.
Plný tet: SKMBT_C22013091912130 - PDF
Plný text: content.csg - PDF
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Characterization and Properties of Titanium-Vanadium Oxide Thin Films Prepared by ArF Laser Ablation
Fajgar, Radek ; Kupčík, Jaroslav ; Šubrt, Jan ; Novotný, F.
Thin films od vanadium-titanium complex oxides were prepared by ArF excimer laser ablation of Tio2 and VO2 targets. The light grey films with thickness of 155 nm were grown on glass and Au substrates and characterized by microscopy, spectroscopy and diffraction techniques. The as-prepared films were nanocrystalline and heating at 450°C in vacuum led to formation of mixture of crystalline V0.95Ti0.05O and TiO nanoparticles. The film shown reversible thermochronic behaviour between 3.0 and 1.4 micrometers. The films, annealed in air oxidize and the colour of the film changes to light yellow. Electrical and optical properties of the films are demonstrated.
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Preparation of Cu3(Si0.5Ge0.5) Nanoplatelets
Dřínek, Vladislav ; Fajgar, Radek ; Palatinus, Lukáš ; Klementová, Mariana ; Novotný, F.
The nanoplatelets possess composition corresponding to Cu3(Si0.5Ge0.5). The 3D collection of electron diffraction patterns has shown that the rooom-temperature structure of the nanoplatelets corresponds to the ?-Cu3Si phase. Evaluation of the diffraction pattern shows that the structure has trigonal symmetry with long period incommensurate modulation. it can be approximately described in a 36-fold superstructure with trigonal unit cell and cell dimensions a=b=16.1A6, c=21.8A6.
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