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Papers by Miroslav Mashlan
Mossbauer Spectroscopy in Materials Science - 2012, 2012
Thermal decomposition of glauconite in air was studied by optical microscopy, thermal analysis, X... more Thermal decomposition of glauconite in air was studied by optical microscopy, thermal analysis, X-ray diffraction, and Mössbauer spectroscopy. The glauconite structure keeps preserved during thermal treatment up to 800 °C; however, simultaneously, a progressive transformation of Fe 2+ and Fe 3+ ions in glauconite structure and water leaving the crystal structure are both observed inducing the symmetry lowering of the iron octahedral positions. The destruction of glauconite structure begins after heating at 900 °C and becomes more intensive with an increase in the treatment temperature. Simultaneously, with the glauconite structure destruction, iron leaving the glauconite structure oxidizes to γ-Fe 2 O 3 , which transforms to α-Fe 2 O 3 .
Journal of Metastable and Nanocrystalline Materials, 2004
57 Fe Mössbauer spectroscopy is demonstrated as an effective tool in the identification, magnetic... more 57 Fe Mössbauer spectroscopy is demonstrated as an effective tool in the identification, magnetic and structural characterization of iron(III) oxides formed by thermally induced oxidative decomposition of FeC 2 O 4 ⋅2H 2 O and by the secondary crystallization of amorphous Fe 2 O 3 nanopowder. AFM measurements revealed that the primary amorphous nanoparticles are between 1 and 3 nm, in accordance with the large surface area of 250 m 2 /g as determined by BET analysis. The temperature depended Mössbauer measurements of amorphous Fe 2 O 3 showed the magnetic transition temperature lower than 70 K with the sharp evolution of the spectral lines between 53 and 76 K as typical for ultrafine and strongly interacted particles. As the primary crystallization product at low temperatures, γ-Fe 2 O 3 (maghemite) was identified by XRD. The broad distribution of magnetic fields in Mössbauer spectra illustrates the broad size distribution of maghemite nanoparticles. The thermally stable α-Fe 2 O 3 (hematite) can be produced by the direct crystallization of amorphous phase at higher temperatures or by the structural transformation of the primarily formed maghemite at lower temperatures. Particles of hematite formed at 200 °C reveal the Morin transition temperature suppressed below 20 K corresponding to the size about 20 nm.
A Mössbauer spectrometer with the collective synchronous motion of the radioactive source and res... more A Mössbauer spectrometer with the collective synchronous motion of the radioactive source and resonant detector has been built. The new special transducer with four drive coils and one velocity pickup coil has been developed. The polyamide fibers serve as suspension brackets, barium ferrite magnets are used. The mechanical construction of transducer allows using different cryostats and furnaces, because the sample is immovable. The resonant detector consists of the thin foil of the organic plastic scintillator with the dissolved substance converting the resonant gamma rays to conversion electrons.
A Mössbauer spectrometer has been developed using a mini transducer and a scintillation detector ... more A Mössbauer spectrometer has been developed using a mini transducer and a scintillation detector with a YAlO3:Ce crystal. Data acquisition is realised via the PIGGY 32/154/320 microcontroller. Mössbauer spectra of 2048 channels can be accumulated in the constant acceleration or constant velocity modes. Pulse height spectra can be collected in the energy window scanning mode. The shape and amplitude of the velocity signal, the energy window of the single channel analyser, and the high voltage of the scintillation detector are controlled by the microcontroller. The velocity range is ±100 mm/s and the nonlinearity of the velocity scale is lower than 0.1%, while the maximum input count rate is as high as 10 MHz with a channel capacity of 2 32 − 1 counts.
A Mö ssbauer spectrometer with a collective synchronous motion of the radioactive source and reso... more A Mö ssbauer spectrometer with a collective synchronous motion of the radioactive source and resonant detector has been built. The new special transducer with four drive coils and one velocity pickup coil has been developed. The drive coils are distributed over a perimeter of the moving frame, which connects the source and resonant detector. This configuration ensures an effective suppression of any mechanical vibrations and excitations in the moving frame. The polyamide fibers serve as suspension brackets, barium ferrite magnets are used. The mechanical construction of the transducer allows the use of various cryostats and furnaces, because the sample is immovable. The spectrometer developed provides an effective application of resonant detectors in a wide range of absorber temperatures.
ChemInform, 2002
Structural and magnetic properties, methods of synthesis, and applications of seven iron-(III) ox... more Structural and magnetic properties, methods of synthesis, and applications of seven iron-(III) oxide polymorphs, including rare beta, epsilon, amorphous, and high-pressure forms, are reviewed. Thermal transformations resulting in the formation of iron oxides are classified according to different parameters, and their mechanisms are discussed. 57 Fe Mössbauer spectroscopy is presented as a powerful tool for the identification, distinction, and characterization of individual polymorphs. The advantages of Mössbauer spectroscopy are demonstrated with two examples related to the study of the thermally induced solid-state reactions of Fe 2 (SO 4 ) 3 .
Biomedical papers of the Medical Faculty of the University Palacký, Olomouc, Czechoslovakia, 2012
The aim of this study was to test an oral contrast solution with maghemite for the magnetic reson... more The aim of this study was to test an oral contrast solution with maghemite for the magnetic resonance imaging of small bowel diseases. The study sample included 3 cohorts: 17 healthy volunteers (group A), 22 patients with small bowel disease (group C). Both groups underwent MR enterography and 24 patients with small bowel disease (group B) underwent magnetic resonance cholecystopancreaticography. Various concentrations in 1000 ml vs 500 ml of experimental solution were tested. All cohorts completed questionnaires evaluating the solution characteristics and side-efects during and after drinking. A maghemite concentration of 800 mg /4 g bentonite in 1000 ml solution was sufficient for proper intraluminal lay-out. An experimental solution of 500 ml was sufficient for magnetic resonance cholecystopancreaticography and 1000 ml for MR enterography. There were no statistically significant differences between groups for taste, taste characteristic or appearance of the experimental solution....
Journal of Sol-Gel Science and Technology, 2014
Hyperfine Interactions, 1999
The thermal decomposition of Fe2(SO4)3 in air has been investigated using transmission Mössbauer ... more The thermal decomposition of Fe2(SO4)3 in air has been investigated using transmission Mössbauer spectroscopy, CEMS and X-ray powder diffraction. The hexagonal alpha-Fe2O3 and cubic beta-Fe2O3 with spinel structure have been identified as products of the decomposition. The influence of the Fe2(SO4)3 particle size on the yield of beta-Fe2O3 in the final product is pointed out and discussed. The size of particles and the calcination temperature are the most important kinetic factors determining the phase composition (beta-Fe2O3/alpha-Fe2O3) of iron (III) oxide.
Nanotechnology, 2011
The nano-modification of selected substrates by means of atmospheric cold plasma treatment was ex... more The nano-modification of selected substrates by means of atmospheric cold plasma treatment was exploited for the two-dimensional (2D) self-assembling of silver nanoparticles (Ag NPs). Such a useful combination of the cold plasma treatment of substrate surface and an immediate easy deposition of Ag NPs creating the 2D self-assemblies on the substrates is published for the first time, to the best of our knowledge. Except for the cold plasma treatment, mainly the following parameters influenced the resulting NP assemblies: the choice of solvent mixture, concentration of Ag NP dispersions, and the deposition technique. The 2D self-assemblies of Ag NPs, providing the same work function as a Ag electrode, were formed on the cold plasma-treated substrates when a drop-casting technique was employed. The possibility of an easy preparation of the Ag NP 2D self-assemblies on substrates without using any chemical agents and/or evaporating chamber could be exploited, e.g. in photovoltaic and light-emitting diode devices.
In this article, the commercial synthetic powdered sample of ilmenite (FeTiO3) has been re-examin... more In this article, the commercial synthetic powdered sample of ilmenite (FeTiO3) has been re-examined by Mössbauer spectroscopy in the paramagnetic regime from 77 K to 280 K and in a magnetically ordered state below 57 K. The effective vibrating mass and the Debye temperature was found to be (78+/-3) amu and (359+/-27) K, respectively. The two sextet components were used
Mossbauer Spectroscopy in Materials Science - 2012, 2012
Thermal decomposition of glauconite in air was studied by optical microscopy, thermal analysis, X... more Thermal decomposition of glauconite in air was studied by optical microscopy, thermal analysis, X-ray diffraction, and Mössbauer spectroscopy. The glauconite structure keeps preserved during thermal treatment up to 800 °C; however, simultaneously, a progressive transformation of Fe 2+ and Fe 3+ ions in glauconite structure and water leaving the crystal structure are both observed inducing the symmetry lowering of the iron octahedral positions. The destruction of glauconite structure begins after heating at 900 °C and becomes more intensive with an increase in the treatment temperature. Simultaneously, with the glauconite structure destruction, iron leaving the glauconite structure oxidizes to γ-Fe 2 O 3 , which transforms to α-Fe 2 O 3 .
Journal of Metastable and Nanocrystalline Materials, 2004
57 Fe Mössbauer spectroscopy is demonstrated as an effective tool in the identification, magnetic... more 57 Fe Mössbauer spectroscopy is demonstrated as an effective tool in the identification, magnetic and structural characterization of iron(III) oxides formed by thermally induced oxidative decomposition of FeC 2 O 4 ⋅2H 2 O and by the secondary crystallization of amorphous Fe 2 O 3 nanopowder. AFM measurements revealed that the primary amorphous nanoparticles are between 1 and 3 nm, in accordance with the large surface area of 250 m 2 /g as determined by BET analysis. The temperature depended Mössbauer measurements of amorphous Fe 2 O 3 showed the magnetic transition temperature lower than 70 K with the sharp evolution of the spectral lines between 53 and 76 K as typical for ultrafine and strongly interacted particles. As the primary crystallization product at low temperatures, γ-Fe 2 O 3 (maghemite) was identified by XRD. The broad distribution of magnetic fields in Mössbauer spectra illustrates the broad size distribution of maghemite nanoparticles. The thermally stable α-Fe 2 O 3 (hematite) can be produced by the direct crystallization of amorphous phase at higher temperatures or by the structural transformation of the primarily formed maghemite at lower temperatures. Particles of hematite formed at 200 °C reveal the Morin transition temperature suppressed below 20 K corresponding to the size about 20 nm.
A Mössbauer spectrometer with the collective synchronous motion of the radioactive source and res... more A Mössbauer spectrometer with the collective synchronous motion of the radioactive source and resonant detector has been built. The new special transducer with four drive coils and one velocity pickup coil has been developed. The polyamide fibers serve as suspension brackets, barium ferrite magnets are used. The mechanical construction of transducer allows using different cryostats and furnaces, because the sample is immovable. The resonant detector consists of the thin foil of the organic plastic scintillator with the dissolved substance converting the resonant gamma rays to conversion electrons.
A Mössbauer spectrometer has been developed using a mini transducer and a scintillation detector ... more A Mössbauer spectrometer has been developed using a mini transducer and a scintillation detector with a YAlO3:Ce crystal. Data acquisition is realised via the PIGGY 32/154/320 microcontroller. Mössbauer spectra of 2048 channels can be accumulated in the constant acceleration or constant velocity modes. Pulse height spectra can be collected in the energy window scanning mode. The shape and amplitude of the velocity signal, the energy window of the single channel analyser, and the high voltage of the scintillation detector are controlled by the microcontroller. The velocity range is ±100 mm/s and the nonlinearity of the velocity scale is lower than 0.1%, while the maximum input count rate is as high as 10 MHz with a channel capacity of 2 32 − 1 counts.
A Mö ssbauer spectrometer with a collective synchronous motion of the radioactive source and reso... more A Mö ssbauer spectrometer with a collective synchronous motion of the radioactive source and resonant detector has been built. The new special transducer with four drive coils and one velocity pickup coil has been developed. The drive coils are distributed over a perimeter of the moving frame, which connects the source and resonant detector. This configuration ensures an effective suppression of any mechanical vibrations and excitations in the moving frame. The polyamide fibers serve as suspension brackets, barium ferrite magnets are used. The mechanical construction of the transducer allows the use of various cryostats and furnaces, because the sample is immovable. The spectrometer developed provides an effective application of resonant detectors in a wide range of absorber temperatures.
ChemInform, 2002
Structural and magnetic properties, methods of synthesis, and applications of seven iron-(III) ox... more Structural and magnetic properties, methods of synthesis, and applications of seven iron-(III) oxide polymorphs, including rare beta, epsilon, amorphous, and high-pressure forms, are reviewed. Thermal transformations resulting in the formation of iron oxides are classified according to different parameters, and their mechanisms are discussed. 57 Fe Mössbauer spectroscopy is presented as a powerful tool for the identification, distinction, and characterization of individual polymorphs. The advantages of Mössbauer spectroscopy are demonstrated with two examples related to the study of the thermally induced solid-state reactions of Fe 2 (SO 4 ) 3 .
Biomedical papers of the Medical Faculty of the University Palacký, Olomouc, Czechoslovakia, 2012
The aim of this study was to test an oral contrast solution with maghemite for the magnetic reson... more The aim of this study was to test an oral contrast solution with maghemite for the magnetic resonance imaging of small bowel diseases. The study sample included 3 cohorts: 17 healthy volunteers (group A), 22 patients with small bowel disease (group C). Both groups underwent MR enterography and 24 patients with small bowel disease (group B) underwent magnetic resonance cholecystopancreaticography. Various concentrations in 1000 ml vs 500 ml of experimental solution were tested. All cohorts completed questionnaires evaluating the solution characteristics and side-efects during and after drinking. A maghemite concentration of 800 mg /4 g bentonite in 1000 ml solution was sufficient for proper intraluminal lay-out. An experimental solution of 500 ml was sufficient for magnetic resonance cholecystopancreaticography and 1000 ml for MR enterography. There were no statistically significant differences between groups for taste, taste characteristic or appearance of the experimental solution....
Journal of Sol-Gel Science and Technology, 2014
Hyperfine Interactions, 1999
The thermal decomposition of Fe2(SO4)3 in air has been investigated using transmission Mössbauer ... more The thermal decomposition of Fe2(SO4)3 in air has been investigated using transmission Mössbauer spectroscopy, CEMS and X-ray powder diffraction. The hexagonal alpha-Fe2O3 and cubic beta-Fe2O3 with spinel structure have been identified as products of the decomposition. The influence of the Fe2(SO4)3 particle size on the yield of beta-Fe2O3 in the final product is pointed out and discussed. The size of particles and the calcination temperature are the most important kinetic factors determining the phase composition (beta-Fe2O3/alpha-Fe2O3) of iron (III) oxide.
Nanotechnology, 2011
The nano-modification of selected substrates by means of atmospheric cold plasma treatment was ex... more The nano-modification of selected substrates by means of atmospheric cold plasma treatment was exploited for the two-dimensional (2D) self-assembling of silver nanoparticles (Ag NPs). Such a useful combination of the cold plasma treatment of substrate surface and an immediate easy deposition of Ag NPs creating the 2D self-assemblies on the substrates is published for the first time, to the best of our knowledge. Except for the cold plasma treatment, mainly the following parameters influenced the resulting NP assemblies: the choice of solvent mixture, concentration of Ag NP dispersions, and the deposition technique. The 2D self-assemblies of Ag NPs, providing the same work function as a Ag electrode, were formed on the cold plasma-treated substrates when a drop-casting technique was employed. The possibility of an easy preparation of the Ag NP 2D self-assemblies on substrates without using any chemical agents and/or evaporating chamber could be exploited, e.g. in photovoltaic and light-emitting diode devices.
In this article, the commercial synthetic powdered sample of ilmenite (FeTiO3) has been re-examin... more In this article, the commercial synthetic powdered sample of ilmenite (FeTiO3) has been re-examined by Mössbauer spectroscopy in the paramagnetic regime from 77 K to 280 K and in a magnetically ordered state below 57 K. The effective vibrating mass and the Debye temperature was found to be (78+/-3) amu and (359+/-27) K, respectively. The two sextet components were used