Fyzikální ústav Akademie věd ČR

Selected results of department 11

Parameter of Internal Particle Alignment - SAR

Magnetic nanoparticles are unique candidates due to their potential usage in biomedical applications, such as MRI contrast agents, the thermal liquidation of the carcinoma (the so-called hyperthermia treatment) and targeted application of medicaments into the tissues [1, 2].

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Detection of Small Amounts of Residual Metal Catalyst in Carbon Nanotubes (CNTs)

Existence of magnetic alignment in Carbon nanotubes (CNTs) has been theoretically predicted [1, 2], but the existence of localized magnetic moment on carbon atoms has not been experimentally observed yet. The main complication is the presence of residual metal catalyst, which is used in the preparation of CNTs, thus the removal of catalyst and subsequent approval of CNT purity is essential [3].

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Fundamental properties of superfluidity: electrical activity of He II studied with second-sound

The electrical activity of superfluid 4He induced by the relative motion of normal and superfluid components has been recently observed. It was induced in two different types of experiments. In a first experiment the electric potential oscillations were generated by a wave of second-sound, the out-of-phase oscillation of the normal and superfluid components. In a second experiment liquid helium was involved in motion by a torsional oscillator whose walls affected the normal component only.  The full text >>

Quantum turbulence: pure superflow through channels

We are studying experimentally the turbulent state of bellows-driven 4He superfluid flows in channels. Turbulence in a superfluid takes the form of a tangle of atomically-thin vortex lines with quantized velocity circulation, which arise as a consequence of the Bose-Einstein condensation of the superfluid [1]. In one project [2] we have studied the dependence of the total length of vortex lines, L, with mean flow velocity, v, in conditions of steady-state turbulence.  The full text >>

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