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Studium utváření mazacího filmu texturovaných konformních kontaktů / Study of lubricant film formation in textured conformal contactsPlachý, Ladislav January 2017 (has links)
The aim of this diploma thesis is to describe mechanisms involved in a lubricant film formation in textured conformal contacts. For exploring of the lubricant film formation, the method of optical interferometry is implemented on a pin-on-disc tribometer. That allows to study an influence of a texture on lubricant film thickness and coefficient of friction of textured samples. These samples have different parameters of a texture. On the basis of these effects and the visual image of the contact, the flow of lubricant in the contact area is described. Shallow dimples lead to larger film thickness in elasto-hydrodynamic lubrication regime. They act like a lubricant reservoir. Deep dimples positively affect film thickness in hydrodynamic lubrication regime, where the effect of shallow dimples descend. During experiments, the formation of a cavitation is observed. The cavitation causes a starvation of dimples in many cases. This leads to reducing of the lubricant film thickness. This effect can be eliminated by appropriate parameters of texture in operational conditions of elements.
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Pokročilé interferometrické metody pro souřadnicové odměřování / Advanced Interferometric Methods of Coordinates MeasurementHolá, Miroslava January 2018 (has links)
This thesis addresses particular topics in the field of the length metrology for nanometrology. Nanometrology deals with dimensional measurements of micro- and nanostructures with a high spatial resolution. It typically combines a microscope imaging with a precise coordinate measurement, usually capable of nanometre resolution using the state-of-art laser interferometry techniques. The development in this field is driven, among others, by emerging advanced nanotechnologies that demand to push further the capabilities and limits of the interferometric techniques to make the nanometre-level dimensional measurement of nanostructures possible. The principal limitations of current systems are the environmental conditions and especially the fluctuations in the refractive index of air. The theoretical part of this thesis aim at analysis of individual parts of laser interferometer. I oriented myself on the study of their advantages/disadvantages and further also the possibilities of their industrial applications. The second part of the thesis presents my work that focused on the influence of the refractive index of air (RIA) on the measurement uncertainty. I experimentally demonstrated an interferometric system with a self-cancellation RIA fluctuations: a transparent photodetector is used for the measurement of the standing wave along the axis of a passive resonator, where the resonator also serves as a reference for the laser wavelength stabilisation. Another optical arrangement, based on a setup of several Michelson interferometers, represents a combination of an interferometer and a refractometer into a single system. This setup was used to study the behaviour of the ambient airflow with respect to the optical path difference and physical separation of the interferometer’s and refractometer’s path. Based on the experimental results I proposed new arrangements for shape measuring interferometers, which combine length interferometry and a tracking refractometer for the direct compensation of RIA fluctuations with geometrically adjacent optical beams. The results indicate an improvement in RIA fluctuation induced uncertainty by a factor of 100. Third part describes the design and implementation of interferometric systems for specific applications. For the industrial environment I developed a compact interferometric displacement gauge which is designed to allow nanometre level measurement using a simplified interferometer construction. For coordinate measurement of the position of the sample up to six degrees of freedom, I realised a compact modular interferometric system, which represents a unique setup together with a stabilised laser source. To measure the position of the sample in an electron beam writer chamber, I designed and implemented a differential interferometer that works in the near infrared domain and uses a new detection method developed for this system. In the fourth part I describe the realisation of a high-speed interferometer with a differential arrangement, which allows evaluation of high-cycle fatigue in material engineering. This method of studying high-cycle fatigue should be beneficial for both the basic research and the engineering practice.
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Snižování tření cílenou modifikací povrchů / Friction reduction by surface texturingMauer, Milan January 2018 (has links)
The aim of this diploma thesis is to experimentally elucidate the connection between the friction of the specimen with the textured surface and the optical observation of the sliding contact surface. The thesis focuses on the configuration of the journal bearing. This configuration is achieved by replacing the block with a circular sapphire section on a block-on-ring tribometer. For exploring of the lubricant film formation, the method of optical interferometry and fluorescence is implemented on the block-on-ring tribometer. These adjustments allow examination of the effect of the textured surface on the friction coefficient and the thickness of the lubricant film. In a mixed mode, the textures cause a significant increase in friction values and reduce the thickness of the lubricant film. The negative influence of dimples increases with the increasing radial load size. In the hydrodynamic mode, the textures have a lower negative effect on the resulting values than in the mixed mode. The changes are dependent on the size of the radial load and the viscosity of the lubricant. In the hydrodynamic mode, cavitation was not observed, and the effect of the textured surface does not correspond to theoretical prerequisites, which is reflected by lower lubricant thickness and higher friction.
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Fázové zobrazování pod difrakčním limitem / Phase imaging below the diffraction limitNečesal, Daniel January 2020 (has links)
Tato diplomová práce se zabývá konstrukcí interferenčních zařízení pro výzkum měření fáze světla na mikro-strukturách a fáze plazmonů na nano-strukturách. V první kapitole je vybudován teoretický základ pro optiku a nano-fotoniku používané v budoucích kapitolách. Následně je popsána interference vln a jejich praktické použití pro prolomení difrakčního limitu pomocí holografie plazmonů. Prvním experimentální sestavou je Machův-Zehnderův holografický mikroskop. Je popsán způsob, jak ho sestavit z běžně dostupných součástek a jak je navržen ovládací software k jeho používání. Následně jsou popsány výsledky naměřené pomocí tohoto zařízení. V poslední kapitole se zaměříme na sestavení holografického SNOM přístroje pro studování plazmonů a jejich interference. Nejdříve popíšeme základní princip a navržení softwaru pro automatizaci měření, pro zrychlení vědeckých postupů. Nakonec předložíme výsledky měření mikroskopu.
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Posouzení geometrické přesnosti obráběcího centra pomocí digitálních inklinometrů / Assessment of geometric accuracy of machining center using digital inclinometersÚnar, Jan January 2021 (has links)
This diploma thesis deals with assessment of geometric accuracy of machining center MCV 754 QUICK. BlueSYSTEM digital inclinometers from WYLER AG, XL-80 laser interferometer from RENISHAW, Ballbar QC20-W from RENISHAW and LaserTRACER self-guiding laser interferometer from ETALON AG were used to measure accuracy. Error of the X straightness in the direction of the Z axis was assessed. The first part of the paper describes the geometric accuracy of the machine, currently available instruments for measuring geometric accuracy and an explanation of straightness. The second part consists of the design of measurements, experiment, evaluation and comparison of results and recommendations for teaching.
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Optimalizace parametrů optické soustavy digitálního holografického mikroskopu pro odražené světlo. / Optimization of parameters of the optical system of reflected-light digital holographic microscope.Dostál, Zbyněk January 2009 (has links)
The diploma thesis deals with the construction design of reflective type of holographic microscope together with the proposal for the mechanical imposition of optical elements. Thesis contains parts where the illumination beam tracing through the optical system is calculated and discussed, followed up with the accuracy requirements for rectification mechanisms and their design. The three-dimensional model of modularly solved microscope is presented in conclusion of this thesis together with selected microscope sub-assemblies.
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Simulátor Hertzova kontaktu / Hertzian Contact ApparatusMarek, Jakub January 2011 (has links)
This diploma thesis deals with the development of experimental apparatus for measuring the real contacts. Phase Shift Interferometry was used for measuring the contacts of steel or brass ball and glass plate. The approach which is desci-bed in this thesis is a unique. It was demonstrated, that the deformation of con-tact body is possible to determine. There is some discusion about final aplicati-on of this optic profilometry for measuring real contacts.
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Polarizační nedokonalosti světla v interferometrii / Polarization Imperfections of Light in InterferometryKučera, Petr January 2009 (has links)
Disertační práce pojednává o polarizačních nedokonalostech optických komponentů, které jsou využívány ke kontrole a k transformaci polarizačního stavu světla. Získané teoretické výsledky jsou pak využity ve vybraných aplikacích, jež ke své činnosti využívají právě polarizace světla. Konkrétně se jedná o zařízení měřící vibrace oscilujících objektů, dále o interferenční měření dvojlomu v transparentních materiálech a konečně, o vybraná témata z optické kvantové komunikace.
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Mazání náhrad kyčelního kloubu / Lubrication of hip joint replacementsRebenda, David January 2016 (has links)
This thesis deals with the experimental study of lubrication of hip joint replacements. The influence of the synovial fluid composition and the head material to the lubricating film thickness were asssesed by using a pendulum hip joint simulator. Both of these effects were assesed under static and dynamic loading conditions. The experimental results showed that the movement of the head against the cup is unnecessary for the separation of the rubbing surfaces by a layer of adsorbed proteins. Composition of the synovial fluid then significantly influences the thickness of the lubricating film. Two opposite extremes have been observed during tests with two model synovial fluids. The first fluid formed a very strong lubricating film. The second sample almost prevent adsorption of proteins and consequently formed only very thin lubricating film. The influence of the material is noticeable when comparing the results obtained with a metal head and ceramic heads. Metal head formes under the same conditions thicker lubricating film. This evidence may be partly influenced by different diametrical clearances, which were in the case of ceramic heads higher.
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Développement de systèmes de microscopie par cohérence optique plein champ étendus spatialement et spectralement / Development of full-field optical coherence microscopy systems with extended spatial and spectral propertiesFederici, Antoine 20 October 2015 (has links)
La tomographie par cohérence optique plein champ (OCT plein champ) est une technique de microscopie interférométrique basée sur l’utilisation d’une source de lumière faiblement cohérente, telle qu’une lampe halogène. Elle permet de réaliser, de façon non invasive, des images tomographiques à plusieurs centaines de micromètres de profondeur dans les tissus biologiques et avec une résolution spatiale isotrope de l’ordre de 1 µm. Ces travaux de thèse concernent le développement de plusieurs systèmes d'OCT plein champ, dans le but de proposer de nouvelles performances et de nouveaux contrastes destinés à l’imagerie en trois dimensions de tissus biologiques. Nous avons dans un premier temps exploité la large bande spectrale d’émission d’une lampe halogène, afin d’apporter une information spectroscopique et d’être capable de distinguer et de caractériser des zones d’un échantillon qui seraient sinon indiscernables. Puis nous avons optimisé la résolution spatiale d’un montage d’OCT plein champ pour atteindre une valeur record de 0,5 µm (dans l’eau) dans les trois directions de l’espace, notamment grâce à l’utilisation d’une bande spectrale adaptée à l’imagerie de tissus, tels que la peau. Un montage dont le champ de vision est élargi à 18 mm x 18 mm a ensuite été développé et appliqué à l’imagerie du signal d’amplitude ainsi qu’à la mesure quantitative du signal de phase résolu en profondeur. Enfin un système utilisant un laser à balayage spectral comme source de lumière combiné à un traitement numérique de correction de la focalisation a été mis en œuvre. Nous avons ainsi démontré la possibilité de réaliser des images en trois dimensions avec une résolution latérale relativement élevée, sans utiliser le moindre déplacement mécanique durant l’acquisition. / Full-field optical coherence tomography (FF-OCT) is an optical technology based on low-coherence interference microscopy for tomographic imaging of semitransparent samples. Non-invasive three-dimensional imaging can be performed with an isotropic spatial resolution of the order of 1 µm. During the PhD thesis, several FF-OCT systems have been reported achieving extended performances or contrast enhanced images relevant for biological tissues imaging. Firstly, a three-band, 1.9-μm axial resolution FF-OCT system has been implemented to perform spectroscopic contrast enhanced imaging of biological tissues over a 530-1700 nm wavelength range. Then, a study of the FF-OCT axial response has been carried out for maximizing the axial resolution of the system. An isotropic spatial resolution of 0.5 µm (in water) has been obtained by combining 1.2-NA microscope objectives with an optimized broad spectral band adapted to biological tissues imaging, such as skin samples. A set-up with an extended field of view of 18 mm x 18 mm has been also designed and applied to amplitude signal detection as well as depth-resolved quantitative phase signal measurement. At last, we developed a technique based on the combination of full-field swept-source optical coherence tomography (FF-SSOCT) with low spatial coherence illumination and a special numerical processing that allows for numerically focused mechanical motion-free three-dimensional imaging.
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