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Study of the Ta2O5 insulating layer degradation
Velísek, Martin ; Majzner, Jiří (referee) ; Sedláková, Vlasta (advisor)
The aim of the thesis is to examine the dielectric function Ta2O5 insulating layers in tantalum capacitors. The capacitor plugged in the regular mode represents a MIS structure of reverse direction. Three different factors can be determined for the residual current of the component according to its charge transmission mode: the ohmic, Pool–Frenkel, tunnel and Schottky. An apparatus was constructed by the author of the thesis to measure the temporary connection between residual current and rise of temperature of the tantalum capacitors. Annealing of three different sets of tantalum capacitors made by different producers was performed at the temperature of 400 K and nominal voltage of 35 V during the period of 20 days.The experiment has proved the residual current in the electric field changes with rising temperature in time as a result of the ion movement. The singular factors of the residual current are influenced during the process. By the “ion movement” is meant the ion drift influenced by the attached electric field and diffusion caused by the concentration gradient. First, the samples were being annealed for c. 2 x 106 s, and then the residual current was being regenerated under the voltage of 5 V for 106 s. The residual current values increased considerably after annealing, and decreased again to more or less the original level after the regeneration, some of the samples reaching even values bellow the original level. The VA characteristics of the samples measured before and after the process of controlled obsolescence, and after the regeneration prove not only a change in parameters of the different current factors, but also a change of the current transmission mechanism employed in the process.
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Transport and noise characteristics of MIS structure and their aplication on the NbO capacitors
Velísek, Martin ; Majzner, Jiří (referee) ; Sedláková, Vlasta (advisor)
The aim of my work was the study of niob-oxide capacitor properties. Capacitor structure NbO-Nb2O5-MnO represents the M-I-S structure where NbO anod has metalic conductivity and MnO2 is semiconductor. The capacitor connected in the normal mode with the positive voltage on the NbO anode represents the MIS structure connected in the reverse direction, when the applied votlage increases the potencial barrier between the insulator Nb2O5 and semiconductor (MnO2). The charge carrier transport is the Nb2O5 layer is determined by the Poole-Frenkel mechanism and tuneling in the normal mode. Poole-Frenkel mechanism of the charge carrier transport is dominant for low electric field in the dielectric layer; tunneling current is dominant for the high electric field. We can estimate the effective thickness of the dielectric layer and the ratio between the Poole-Frenkel and tunelling current from the modeling of measured VA characteristics.
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Figural painting in hanging picture
Kroutil, Jan ; Hůla, Zdenek (advisor) ; Velíšek, Martin (referee)
A content of the bachelor thesis is a theoretical reflection about possibilities of a painted depiction of a human figure and a phenomenon of a hanging picture. The theme of the figural painting is further applied to an educationally-therapeutic practice as an art activity subject for people with mental retardation. The work also contains a documentation of the author's own painting and its reflection. Key words: painting, human figure, stylization, expression, hanging picture, education, mental retardation Powered by TCPDF (www.tcpdf.org)
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What do children draw (not only ) on the asphalt
Hnyková, Michaela ; Velíšek, Martin (advisor) ; Kafková, Helena (referee)
The topic of this thesis What do children draw (not only) on the asphalt is to explore a material potential of outside environment as a specific device for teaching art education. The first part defines the role of the arts in contemporary education system, sets out the main goals and points out specialties of the field. The next section deals with the observation of spontaneous creative expressions of children on non-traditional sourfaces, their place in the natural need for exploration, and playing as a means of understanding the world. Compares the difference of the creation in outdoor environments on unconventional surfaces and the classical indoor creation and deals with the potential use of this knowledge. Looks for possibilities which would enrich the teaching of art and offer teachers new inspiration. Finally, on the basis of my own interventions, verifies the applicability of theoretical findings and their possible application in teaching at primary schools.
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Painting as a physical, gestical action. Gesture and physical space experience of reality in the landscape
Lešková, Kristýna ; Hůla, Zdenek (advisor) ; Velíšek, Martin (referee)
Lešková, K.: Painting as a physical, gestical action - Gesture and physical space experience of reality in the landscape. [MA thesis] Prague 2012 - Charles University in Prague, Faculty of Education, Departement of Art Education, 84 pages. This work seeks to bring selected moments in the history of painting, which combines the gestural element and the physical and gestural actions. This award is largely bordered by landscape theme. Part is a philosophical reflection about the nature of painting as a physical object. Based on new findings related to the reflection of own artistic creation, author created a set of artworks with an emphasis on gestural expression. Linking acquired knowledge and creative experience led to the creation of didactic art range of tasks suitable for teaching elementary school pupils from which consist effort to achieve creative thinking and developing the gesture and action at work. Great emphasis is placed on the motivational process. Part of the task is verified by experience in elementary school. The whole work is regularly supplemented by the visual documentation.
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Landscape and its Changes over Time
Košatová, Barbora ; Šmíd, Jan (advisor) ; Velíšek, Martin (referee)
Bachelor thesis has the character of theoretical studies mapping the landscape changes in the visual arts in various artistic epochs with subsequent applications topic in the field of didactics of art education and its distinctive transformations in the visual part. It refers to the landscape as the period; phenomenon. Transformations of the landscape are handled through the landscape and figurative relationship, or component in question in a work of art, most commonly in the image. The design of the didactic project for hours of Art education, apply the theme changes the landscape in order to arouse pupils' interest in the transformation of surrounding of the landscape the landscape itself, which subsequently expresses with peculiar transformation through the use of visual media. Key words: landscape, change, time, art, landscape painting, photography, place, sky, the effects of art
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