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Popularisation of Science in the Czech Republic
Holčapková, Martina ; Walek, Agata (referee) ; Baumgartnerová, Alena (advisor)
Bakalářská práce se zabývá tématem popularizace vědy. Cílem práce je definovat subjekty zabývající se popularizací vědy a zjistit informovanost veřejnosti o daném tématu. První část práce je zaměřena na definici termínu popularizace vědy. V druhé části jsou popsány rozdíly v učení dospělých a dětí. Třetí část ukazuje subjekty popularizace vědy a následující kapitola, založená na dotazníku, popisuje povědomí obyvatel Brna a jeho okolí o možnostech popularizace vědy. Závěrečná kapitola se věnuje tvorbě popularizačně naučného programu zaměřeného na téma elektřina a magnetismus.
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Theory of spin-dependent transport in magnetic solids
Wagenknecht, David ; Turek, Ilja (advisor) ; Minár, Ján (referee) ; Šipr, Ondřej (referee)
of doctoral thesis Theory of spin-dependent transport in magnetic solids David Wagenknecht Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University 2019 Theoretical and ab initio description of realistic material behavior is complicated and combinations of various scattering mechanisms or temperature effects are often neglected, although experimental samples contain impurities and modern electronics work at finite temperatures. In order to remove these knowledge gaps, the alloy analogy model is worked out in this thesis and implemented within the fully relativistic tight- binding linear-muffin-tin orbital method with the coherent potential approximation. This first-principles framework is shown to be robust and computationally efficient and, consequently, employed to investigate bulk solids and their spintronic applications. Unified effect of phonons, magnons, and alloying gives agreement with literature for temperature-dependent electrical transport (longitudinal and anomalous Hall resistivities) and scattering mechanisms are explained from electronic structures. Moreover, novel data help to identify defects in real samples and experimentally hardly accessible quantities are presented, such as spin polarization of electrical current. Calculated results for both zero...
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Electromagnetic power actuators
Kadlecová, Lucie ; Vorel, Pavel (referee) ; Folprecht, Martin (advisor)
This master thesis focuses on literature research of problematics linked to power actuators working on electromagnetic principle to accelerate metal projectiles. It’s goal is mathematical analysis and constuction of selected type of electromagntic power actuator – induction coilgun
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Elektronové vlastnosti sloučenin RPd5Al2
Zubáč, Jan ; Javorský, Pavel (advisor)
We have studied magnetic properties of the intermetallic NdPd5Al2 com- pound by means of specific heat and magnetization measurements and neutron scattering. The compound crystallizes in the tetragonal I4/mmm space group with lattice parameters a =4.147 ˚A and c =14.865 ˚A, orders antiferromagnet- ically below TN =1.3 K and presents large magnetocrystalline anisotropy due to the crystal-field effects. The obtained magnetic phase diagram is charac- terized by two distinct magnetically ordered phases similarly to structurally re- lated tetragonal RTX5 and R2TX8 compounds. The zero-field antiferromagnetic phase is characterized by the propagation vector k = (1 2 00) and antiferromag- netic coupling of Nd moments along the teragonal c-axis with the amplitude of magnetic moments of 2.22 µB/Nd as was revealed by neutron diffraction. The transition from the paramagnetic to magnetically ordered in zero field is the first-order phase transition. The CF excitations in NdPd5Al2 were detected by means of INS at 3.0 meV, 7.4 meV, 8.6 meV and 17.1 meV. We further compare our findings about CF in NdPd5Al2 obtained from INS, susceptibility analysis and first-principles calculations and confront them with the experimental mag- netization and magnetic specific heat data. Our results will be also discussed with respect to related...
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Hybrid Energy Harvesting Device
Rasocha, David ; Rubeš, Ondřej (referee) ; Hadaš, Zdeněk (advisor)
This bachelor theasis is focuses on the design of a hybrid piezoelectric vibratory genera-tor. The main idea is to place a permanent magnet on the end of the piezoelectric beam and to place the coil appropriately in order to make a electromagnetic generator. The coil will generate a electrical voltage on load, when the magnetic field is passing throught coil. The piezoelectric beam will also generate voltage, depending on its deformation. For modeling, Femm, Matlab and Simulink will be used.
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Conceptual design of a precision manipulator
Stuchlík, Petr ; Pavlík, Jan (referee) ; Vetiška, Jan (advisor)
This diploma thesis deals with the problems of analysis and the subsequent design of a precision manipulator used as a microscope table. The first part od the final thesis deals with the problems associated with the movement of the test sample within the electron microscope. Subsequently, possiblle design variants were proposed, further developing the next steps fot the correctness and functionality of manipulator. The individual force loads of the components were calculated. The result of the work was constructed as a CAD model with subsequent transfer to the assembly drawing.
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Electromagnetic power actuators
Kadlecová, Lucie ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
This master thesis focuses on literature research of problematics linked to power actuators working on electromagnetic principle to accelerate metal projectiles. It’s goal is mathematical analysis and constuction of selected type of electromagntic power actuator – induction coilgun
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Electronic structure and magnetic properties of the materials with strong electron-electron correlation
Kozub, Agnieszka Lidia ; Shick, Alexander (advisor) ; Legut, Dominik (referee) ; Minár, Ján (referee)
In this thesis, we summarize the material-specific theories of strongly correlated systems and apply them to selected materials. We describe and apply the corre- lated band theory methods: the local density approximation plus Coulomb U, and the density functional theory plus exact diagonalization of single impurity An- derson model. First, we investigate the systems containing impurity atoms: cobalt impurity located in the bulk copper and samarium, and neodymium adatoms on the surface of graphene. We present the spectral densities and study the magnetism of those compounds. Afterwards, we analyze three Np-based compounds: NpPt2In7, Np2Ni17 and NpBC. For all three compounds we analyze the spin, orbital and to- tal magnetic moments and the total density of states, as well as its projections for selected orbitals and spins. Moreover, for NpPt2In7 and NpBC we perform the to- tal energy analysis between different magnetic moment arrangements on the Np atoms.
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Optical response of magnetic materials
Wagenknecht, David ; Ostatnický, Tomáš (advisor)
David Wagenknecht: Abstract of a diploma thesis Optical response of magnetic materials, 2014 Magnetooptical properties of anisotropic semiconductors are studied to describe asymmetry of Ga1−xMnxAs, because theoretical calculations predict extraordinary behaviour of reflectivity. Analytical formulae to describe materials with non-diagonal permittivity are derived and they are used for the numerical calculations to describe the optical response of the samples available for the measurement. The transversal Kerr effect is calculated and it exhibits asymmetry in both rotation of the plane of polarization and ellipticity of circularly polarized light due to asymmetry in reflectivity. Moreover, longitudinal and polar magnetization are studied because of the influence on the observability of the phenomena. Results are not only used to discuss conditions, which must be satisfied to prove the asymmetry, but also the actual experimental setup is designed to prepare the measurement. 1
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