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Parameterization of body discomfort of driver and front passanger in a monotone load during driving by car
Kaucová, Jana ; Jelen, Karel (advisor) ; Veis, Martin (referee)
Title: Parameterization of body discomfort of driver and front passanger in a monotone load during driving by car Objectives: The aim of this work based on the implemented case study is determination utilization of selected subjective and objective methods to assess discomfort sitting position of driver and front passanger in the monotone load during driving by car. Methods: This thesis is type of descriptive - association qualitative research. In practical part the objective discomfort parameters were monitored using Mobile system for scanning and evaluation of occupational safety and hygiene and the subjective parameters using Questionnaire physical map in combination with modified Borg scale, the mental state was monitored using modified questionnaire POMS. Results: Detailed link was not proved in context of subjective and objective methods or roles, the measurements were too influenced by entering factors and variability of observed objective parameters. The skin temperature, wetness and heart rate appear to be unsuitable for monitoring the sitting discomfort in realistic conditions, subjective methods are usable in research. Their results showed that the subjective discomfort and fatigue grew more during ride back. Pause resulted in reduced subjective discomfort. Keywords: skin temperature,...
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Studium fyzikálních vlastností Heuslerových slitin
Beran, Lukáš ; Veis, Martin (advisor) ; Mistrík, Jan (referee)
This diploma thesis is devoted to systematic study of structural trans- formations of Heusler alloys by means of spectroscopic ellipsometry and magneto-optical spectroscopy. Structural transformations in these alloys are induced by different microscopic mechanisms. Obtained experimental results were confronted with theoretical calculations. This allowed the discussion of obtained results and suggestion of their interpretation. In the case of Co- Fe-Si alloys, changes in optical and magneto-optical properties with change of Co-Fe ratio were observer. This was explained by lowering of the gap for minority spins with increasing Fe concentrations. Temperature dependent optical and magneto-optical properties of Ni-Mn-Ga alloy showed the pres- ence of so-called Martensitic transformation from cubic to tetragonal phase. A study of Mn-Rh-Co-Sn alloys did not show a clear dependence of physical properties upon the concentration of Rh and Mn. This was explained by strong strain inside the samples, which distorted obtained results. 1
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Investigation of spin polarization by laser spectroscopy
Kuchařík, Jiří ; Němec, Petr (advisor) ; Veis, Martin (referee)
Spintronics is a new branch of electronics, which uses not only the charge of electron but also its spin for transfer and processing of information. For re- al applications it is necessary to understand, how the magnetic state of matter changes not only in time but also in space. This diploma thesis is therefore de- voted to the imaging of magnetic domains in ferromagnetic semiconductors by purely optical methods, which are based on the usage of the magneto-optical ef- fects. In first part of the thesis we concentrated on the optimalization of existing polarizing microscope, whose function is based solely on the polar Kerr effect. After the optimalization we try to use this setup to observe magnetic domains in ferromagnetic semiconductor GaMnAs by the means of the magnetic linear dichroism. 1
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Pokročilé simulace fotonických struktur metodou FDTD
Vozda, Vojtěch ; Veis, Martin (advisor) ; Richter, Ivan (referee)
Finite-Difference Time-Domain method (FDTD) is based on numerical solution of Maxwell's equations, nowadays widely used for simulating optical response of photonic structures. This paper provides brief introduction to the FDTD method and several important extensions which make the basic code much more versatile. In order to broaden analysis of photonic structures, transfer matrix method (TMM) is also involved. The code is firstly tested using simple model structures which optical response might be compared with different numerical or even analytical approaches. Debugged code is used to improve photonic crystals for enhanced sensitivity of biosensing devices based on refractive index changes of sensed medium. Last but not the least, properties (sensitivity and Q-factor of resonant peak) of holey waveguide are investigated in one-, two- and three-dimensional simulation. It is shown here, that even this simple structure may compete with complex photonic crystals in the field of biosensors. Powered by TCPDF (www.tcpdf.org)
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Spectroscopic studies of Co2MnSi Heusler alloy
Král, Daniel ; Veis, Martin (advisor) ; Uhlířová, Klára (referee)
In the last years Heusler compounds showed properties that make them suitable materials for spintronic applications. Their magnetic and optical proper- ties are strongly dependent on their structural order, making it an important mat- ter of research. Co2MnSi can exhibit diferent types of lattices, i.e. B2 and L21, while B2 transits to L21 by the process of annealing. In this work we present a stu- dy of optical and magneto-optical properties of Co2MnSi thin films with different annealing temperatures. Spectroscopic ellipsometry as well as magneto-optical spectroscopy in linear and quadratic configurations were used as experimental techniques. Our goal was to determine wheather the magneto-optical meassure- ments are more accurate tools for lattice transitions studies than spectroscopic ellipsometry.
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Study of dynamically induced changes of magnetic properties in nanostructures
Ohnoutek, Lukáš ; Veis, Martin (advisor) ; Hamrle, Jaroslav (referee)
The aim of this bachelor thesis is the study of the changes of magnetic properties of the Co/GdOx interface under the influence of electric field. The main motivation is to identify the mechanism of the observed changes. Spectroscopic magneto-optic methods are used because of their high sensitivity and depth resolution. This makes them suitable for the study of the interface effects in thin multilayered structures. Two experimetal setups have been assembled to measure hysteresis loops and magneto-optical spectra of non-modified samples and voltage-modified samples. Measured magneto-optical spectra are compared to theoretical calculations of magneto-optic Kerr effect for the studied structure. The measurements together with the theoretical models prove that oxygen ions migrate from GdOx to Co under applied voltage.
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Investigation of magnetically-ordered materials by optical spectroscopy
Saidl, Vít ; Němec, Petr (advisor) ; Veis, Martin (referee)
In this work we study thin epilayers of new antiferromagnetic semimetal CuMnAs by time- resolved magneto-optical experiments. In 10 nm layers of CuMnAs, we observed a harmonic dependence of the dynamical magneto-optical signal on the orientation of probe pulse linear polarization. This shows that in this 10 nm layer there is an in-plane uniaxial magnetic anisotropy which can be detected due to a quadratic magneto-optical effect - magnetic linear dichroism. From the measured data we also estimated the Néel temperature and the spectral variation of the magneto-optical coefficient describing the magnitude of the magnetic linear dichroism in this sample.
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Calculation of optical response of photonic structures by FDTD method
Vozda, Vojtěch ; Veis, Martin (advisor) ; Richter, Ivan (referee)
FDTD method is based on Maxwell's equations and this thesis describe how to make these differential equations computer readable for numerical solution known as the Yee algorithm. Time step dependence on spatial step is examined here in order to obtain stable solution. Discrete Fourier trasform is defined to obtain frequency dependent transmission and reflection coefficients. Programmed simulation is tested on analytically solvable structures even on slightly more complex systems whose optical response was computed by other type of simulation. Finally photonic crystals and their application as biosensors are discussed. Particular shape of photonic crystal is examined in details (frequency spectrum dependence upon spatial resolution, inaccuracy in geometry, different compounds in holes, geometry modification).
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Study of physical properties of nanostructures using magneto-optical techniques
Beran, Lukáš ; Veis, Martin (advisor) ; Mistrík, Jan (referee)
Magneto-optical spectroscopy methods are used to study magnetic pro- perties of materials down to nanometer dimensions due to its high sensiti- vity and non-contact nature. This requires sophisticated experimental setup, advanced technical equipment and precise optical components arrangement. This thesis describes the basic physical principles of magneto-optical Kerr spectroscopy. On the basis of these principles is designed and developed a new, much simpler experimental setup with crossed polarizers. This arran- gement has the same order of sensitivity and accuracy of measurement as commonly used modulation techniques to which it is compared in this work. Finally, this arrangement is applied to the study magneto-optical properties of selected magnetic structures and these properties are discussed. 1
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