The series of DyF3nanosized samples was synthesized by the colloidal chemistry method. The microwave-assisted hydrothermal treatment was used for the first time for the modification of DyF3nanoparticles. Transmission electron microscopy images show that the DyF3nanoparticles have average particle size of about 16–18 nm and the size distribution becomes narrower during the microwave irradiation. The X-ray diffraction analysis shows the narrowing of the diffraction peaks versus microwave treatment time. The experimental data demonstrates restructuring of the nanoparticles and their crystal structure becomes closer to the ideal DyF3regular structure during the microwave irradiation of colloidal solution. The defect-annealing model of the microwave-assisted hydrothermal modification process is suggested.

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The series of DyF3 nanoparticles samples are synthesized by the hydrothermal treatment in autoclave at 140°C, 160°C, 200°C and 230°C for 24 h. The samples are characterized by X-ray powder...

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International audienceThermal modification of wood is an effective method to improve some of the properties of wood. It is reported on studies of vacuum thermal-treated wood species by magnetic resonance methods. Wood species such as Scots pine (Pinus sylvestris), birch (Betula pendula), Russian larch (Larix sibirica), Norway spruce (Picea abies), small-leaved lime (Tilia cordata) were vacuum treated by heat at 220 °C with various durations up to 8 h. This selection of wood species was investigated by electron paramagnetic resonance, nuclear magnetic resonance and microscopy methods before and after the thermal treatment. Electron paramagnetic resonance experiments revealed changes in the amount of free radicals in samples with the thermal treatment duration. Additional information on magnetic relaxation of 1H nuclei in samples at room temperature was obtained. Optical microscope analysis helped to detect structural changes in the thermally modified wood. Important properties of wood such as wood hardness and humidity absorption were also studied. The original results that were obtained correlate and complement each other, and clarify changes in the wood structure that appear with the heat treatment

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The pulsed NMR method was used to study the spin kinetics of liquid 3Не in a sample of oriented Al2O3 aerogel, containing DyF3 nanoparticles with an average size of 5 nm, at temperatures of 1.5−3 K. DyF3 is a dipole dielectric ferromagnet with a phase transition temperature of TC = 2.55 K, while the diamagnetic ordered Al2O3 aerogel is used as a magnetic diluting agent to ensure the optimal conditions for observing the 3Не nuclear magnetic resonance in this system. No anomalies in the spin kinetics of 3Не contacting with this sample that could be related to the phase transition have been observed. A method for adding paramagnetic impurities to aerogel was proposed.