Práca sa zaoberá vývojom ďalekej infračervenej spektroskopie v silnom magnetickom poli. Kombinácia ďalekej infračervenej spektroskopie a silného magnetického poľa je veľmi dôležitým nástrojom pri charakterizácii materiálov, ako sú jedno-molekulové magnety. Predstavuje tiež ideálnu experimentálnu techniku, ktorá dokáže skúmať a objasniť vlastnosti nových 2D materiálov. Ďaleká infračervená spektroskopia v magnetickom poli taktiež umožňuje študovať elektrónovú paramagnetickú rezonanciu (EPR) jedno-molekulových magnetov s veľmi veľkým delením pri nulovom poli, hlavne na báze komplexov prechodných kovov alebo lantanoidov, v ktorých bežne používané EPR systémy neposkytujú experimentálny prístup k magnetickým rezonančným prechodom. V práci sú podrobne popísané dve zostavy ďaleko infračervených spektrometrov pripojené k supravodivým magnetom. Prvá opísaná zostava, ktoré sa nachádza na univerzite v Stuttgarte, je už zmontovaná a jej výkon je diskutovaný. Magneto-optické merania jedno-molekulových magnetov vykonané na tejto zostave sú predstavené. Druhá magneto-optická zostava čerpá zo skúseností získaných pri prvej zostave a je určená pre CEITEC.

The work analyses formation of deformations of RF magnetic field within the environment of electrically and magnetically conductive materials. An analytic solution of the problem is created and the problems of numerical modeling are solved. In theoretical way, the work also familiarize with the use of magnetic resonance imaging method - the spin echo method (SE), with its features and possibilities of its use within the aim of the project. This method is used for experimental measurements of electrically conductive materials in the NMR laboratory in ISI AV Czech Republic. Results of the simulation are compared with results of the experimental measurement.

Project Magnetotherapeutic device for Child Neurology in his forepart paies medical use of Pulsatile Magnetic Field. Summaries a therapeutic effects of field which is interacting with biotic issue and determines which of those effects are acceptable for treatment of Infantile Paralysis. Below it describes single Bio-Parametres of Pulsatile Magnetic Field and analyses reasons and effects of Infantile Paralysis. In second part is described a block diagram of magnetotherapeutic device for treatment of Infantile Paralysis. Described is principle of function of blocks. In third part is defined circuit solving of controlling, supervisory and generating part of magnetotherapeutic device. Function and wiring of components is described in detail. There is also created a Printed Circuit Board. Device is controlled by three microcontrollers, therefore there are described flowcharts and controlling programs for microcontrollers.

The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.

This thesis deals with distribution of magnetic fields in the DC machine. Part of this thesis is the introduction of DC machines, principles of operation and distribution of DC machines. There is also discussed electrically commutated motors. The thesis demonstrates the types of permanent magnets and their properties. Then there is an analysis of the magnetic field electrically commutated motor Atas Nachod in the Ansoft Maxwell. Using Ansoft Simplorer, switching is carried out of the engine. Another part of this work is the analysisthe magnetic field electrically commutated motor Atas Nachod for three types of slot of the stator of the engine. Here it is seen what impact the change has slot on the distribution of magnetic field in the EC motor. Finally, training is carried out measurements of electrically commutated motor BOYANG BY92BL48-4000-2200.

This work includes the theory of circuit breaker construction and is focused mainly on overload function. It mainly deals with electronic circuit breakers, i.e. equipped with an electronic trip unit. The work is focused on the part of trip unit - maglatch of trip unit. For the purposes of simulation, the geometric model is created. Maxwell program is used for the simulation. The work describes the options for conditions input which are necessary for simulation. Using the distribution of magnetic field intensity and magnetic flux density in the section of trip unit maglatch is determined by the simulation. Furthermore, the force effects acting on the armature of the maglatch are calculated. Force values and the directions acting on the armature are determined by changing the simulation parameters - shift of the armature and coil current. Simulations are performed both for steady-state and for dynamic simulation – movement of armature is taken into account. The supply source for the maglatch is created by an external circuit.

The presented dissertation thesis analyses artefacts in diffusion-weighted images. In medical practice, the artefacts can impede the diagnostics of pathological tissues and, therefore, need to be eliminated. As the first step within the thesis, an analysis of the most frequent artefacts in diffusion-weighted images is performed, and the hitherto known approaches to artefact elimination are described. In order to facilitate the reduction of artefacts caused by the inhomogeneity of the static magnetic field and induced by eddy currents, a novel three-measurement method is shown. This technique will find application especially in measuring the diffusion coefficient of isotropic materials. At this point, it is important to note that a significant and commonly found problem is the magnetic susceptibility artefact; different magnetic susceptibility values at the boundary between two materials can cause magnetic field inhomogeneities and even complete loss of the signal. Therefore, we designed a novel method for the measurement of magnetic susceptibility in various samples of magnetically incompatible materials, which do not produce any MR signal. The technique was experimentally verified using a set of differently shaped diamagnetic and paramagnetic samples. In addition to the magnetic susceptibility problem, the thesis presents artefacts such as noise, motion-induced items, hardware limitations, chemical shift, and the dependence of the diffusion coefficient on the temperature. To enable precise measurement of the diffusion coefficient, we proposed a thermal system; in the experiment, it was determined that when the measurement error does not exceed 5%, the temperature change should not be higher than 0,1 °C. In the final sections of the thesis, practical application examples involving the designed methods are shown.

This thesis presents a numerical method for the phase-resolving simulation of rigid particles and deformable bubbles in viscous, magnetohydrodynamic flows. The presented approach features solid robustness and high numerical efficiency. The implementation is three-dimensional and fully parallel suiting the needs of modern high-performance computing. In addition to the steps towards magnetohydrodynamics, the thesis covers method development with respect to the immersed boundary method which can be summarized in simple words by From rigid spherical particles to deformable bubbles. The development comprises the extension of an existing immersed boundary method to non-spherical particles and very low particle-to-fluid density ratios. A detailed study is dedicated to the complex interaction of particle shape, wake and particle dynamics. Furthermore, the representation of deformable bubble shapes, i.e. the coupling of the bubble shape to the fluid loads, is accounted for. The topic of bubble interaction is surveyed including bubble collision and coalescence and a new coalescence model is introduced. The thesis contains applications of the method to simulations of the rise of a single bubble and a bubble chain in liquid metal with and without magnetic field highlighting the major effects of the field on the bubble dynamics and the flow field. The effect of bubble coalescence is quantified for two closely adjacent bubble chains. A framework for large-scale simulations with many bubbles is provided to study complex multiphase phenomena like bubble-turbulence interaction in an efficient manner.

Melt flow plays an important role in directional solidification of multicrystalline silicon influencing the temperature field and the crystallization interface as well as the transport of impurities. This work investigates the potential of a traveling magnetic field (TMF) for an active control of the melt flow. A system of 3D numerical models was developed and adapted based on open-source software for calculations of Lorentz force, melt flow, and related phenomena. Isothermal and non-isothermal model experiments with a square GaInSn melt were used to validate the numerical models by direct velocity measurements. Several new 3D flow structures of turbulent TMF flows were observed for different melt heights. Further numerical parameter studies carried out for silicon melts showed that already a weak TMF-induced Lorentz force can stir impurities near to the complete mixing limit. Simultaneously, the deformed temperature field leads to an increase of the deflection of crystallization interface, which may exhibit a distinct asymmetry. The numerical results of this work were implemented in a research-scale silicon crystallization furnace. Scaling laws for various phenomena were derived allowing a limited transfer of the results to the industrial scale.

This thesis presents an experimental study which investigates the behaviour of gas bubbles rising in a liquid metal and the related bubble-driven flow under the influence of external DC magnetic fields. The experimental configuration considered here concerns a cylindrical container filled with the eutectic alloy GaInSn. Argon gas bubbles are injected through a single orifice located at the container bottom in the centre of the circular cross-section. A homogeneous magnetic field was generated by a Helmholtz configuration of a pair of water-cooled copper coils. The magnetic field has been imposed either in vertical direction parallel to the main bubble motion or in horizontal direction, respectively. A vertical magnetic field stabilizes and damps the liquid metal flow effectively. The temporal variations of the fluid velocity with time become smaller with increasing magnetic induction. The velocity magnitudes are decreased, and the velocity distributions along the magnetic field lines are smoothed. The flow field keeps the axisymmetric distribution. A horizontal magnetic field destabilizes and enhances the flow within a range of moderate Hartmann numbers (100 < Ha < 400). The flow becomes non-axisymmetric due to the non-isotropic influence of the magnetic field. In the meridional plane parallel to the field lines, the flow changes its direction from a downward to an upward motion. Enhanced downward flows were observed in the meridional plane perpendicular to the field lines. The liquid velocity in both planes shows strong, periodic oscillations. The fluid motion is dominated by large-scale structures elongated along the magnetic field lines over the entire chord lengths of the circular cross-section.