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Optimization of the imaging spectrophotometer
Vodák, Jiří ; Antoš, Martin (referee) ; Ohlídal, Miloslav (advisor)
Thesis deals with an optimization of an imaging spectrophotometer which consists of a monochromator, a CCD camera with extended detection range to UV spectra and an imaging system. Main benefits of the optimization are utilization of a new lightsource, a connection of the monochromator and the imaging system by a fibre bundle and upgrade of a sample angle adjustment system by use of a auxiliary CCD camera. More changes were made to increase accuracy of measurements and ease of use of the apparatus.
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The Official Website of Research Group
Blaheta, David ; Jaroš, Jiří (referee) ; Ohlídal, Miloš (advisor)
The contents of this bachelor's thesis consists in a development of a research group website according to the specified requirements of the proposer. The created web pages are constructed dynamically and provide the user a lot of amenities not only in the field of information acquisition but also in the field of the administrator's work. The thesis describes information technologies which was utilized for realization, PHP, MySQL, XHTML, CSS and JavaScript. Moreover, it describes functions implemented in the portal and the way of their implementation. Namely, these functions are the following: diary of events, administration of publications, creation of animations, sending news on an e-mail address, joint work with Mathcad etc. A part of the thesis contains user's and administrator's manuals with pictures from the programmed application. As an enclosure, an electronic medium is provided with the source codes of the entire application.
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Application of Spectral Analysis in 3D Evaluation of Surfaces
Brillová, Kateřina ; Valíček, Jan (referee) ; Hloch,, Sergej (referee) ; Ohlídal, Miloslav (advisor)
Thesis deals with the spectral analysis of 3D surface topography. The surface is described by a random function. Theoretical starting points necessary for right introduction and understanding of basic notions used within the framework of the surface topography spectral analysis are exactly formulated. They lie in the theory of random functions, the theory of the Fourier transform and the theory of signal processing. The notions mentioned are: the areal power spectral density (APSD) of a surface, the radial power spectral density (RPSD) of a surface and the angular power spectrum density (AnPSD) of a surface. These notions are introduced in their discrete form and generalized for the two-dimensional case. The thorough discussion of possible mistakes and inaccuracies which can be done during the application of spectral analysis techniques in a surface topography evaluation is performed. The procedure of APSD estimation by means of the periodogram method combined with the Welch´s method is discussed. The principle and capabilities of the optical profilometer MicroProf?FRT used for the surface topography measurement are described. Our original computer program computing APSD, RPSD and AnPSD is described too. The 3D spectral analyses is applied to surfaces generated by AWJ cutting, plane grinding and casting. We have focused our attention to AWJ cut surfaces, 3D spectral analyses of which brings new still unpublished opportunities of the surfaces topography evaluation. The influence of technological parameters on these AWJ cut surfaces topography is studied. The conclusion of the study is that results of the spectral analyses of these surfaces topography strongly depend on the technological conditions of the surfaces generation. An original procedure of the ASPD shape evaluation within individual regions of its frequency domain is mentioned. This procedure brings new substantial knowledge concerning the topography of surfaces. Results obtained from surfaces generated by plane grinding and casting are presented like examples of results from non-isotropic and isotropic surfaces.
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Design of a mirror collimator for a light beam outgoing from a silica fibres bundle of a circular cross section.
Vodák, Jiří ; Brillová, Kateřina (referee) ; Ohlídal, Miloslav (advisor)
Imaging spectroscopic reflectometry is an innovative method for studying optical properties of thin layers. This method allows as studying large areas of thin layers. Imaging spectrophotometer designed in The Institute of Physical Engineering was supposed to allow measurements along areas of about 25 mm x 25 mm. However this area was not achieved. To achieve desired dimensions of the area under study it is necessary to redesign the optical transmission setup between a source of monochromatic light and the imaging spectrophotometer.The old spectrophotometer design consists only of a mirror collimator not sufficient enough to collimate a rectangle shaped light beam on the output of the monochromator. The new design will consist of optical cable of silica fibers transforming the rectangle input light beam into a light cone which will be easier to collimate by a mirror collimator.
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Use of finite element method for stress evaluation in layers for optical applications
Tesařová, Anežka ; Ohlídal, Miloslav (referee) ; Burša, Jiří (advisor)
This thesis is concerned with the mechanical stress generated in thin layers applied on a substrate. The application takes place at high temperatures and due to different coefficients of thermal expansion of materials, the sample is deformed, and thereby the stress is generated. The first part of the thesis includes the derivation of the Stoney formula for uniaxial and biaxial stress in a layer. Besides, analytical calculations of the normal stress in the layer for the simplified link model, and shear stress on the layer interface were evaluated. The main part of the work consists of solving the problem using FEM modeling. Because the actual temperature behavior during the application was not known, a fictitious temperature load was used as an input. For the samples, the coefficients of thermal expansion of the layer were then searched so that the thermal load resulting deflection corresponds to the experimental data. Three types of models were created, namely the link body model, the axisymmetric model, and the solid model. The axisymmetric model was used for the calculation of samples forming circular isolines during deformation and a volume model for samples forming elliptical isolines. The result of the FEM calculations was the normal stress in the applied layers, for which corresponding relationships were created using regression analysis.
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The Official Website of Music Group
Štěpaník, Zdeněk ; Ohlídal, Miloš (referee) ; Jaroš, Jiří (advisor)
This bachelor thesis deals with an implementation of the official website of music group Marshal. The website has been created using programming language PHP and is based on MySQL database. It includes fans registration, photogallery that supports rating and commenting photos, discussions with an option to reply on a particular thread, articles, news, enquiries, etc. The key component for administration is CMS system which was developed to manage contents of the website as a part of this thesis.
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Numerical simulation of the laser light scattering from rough surfaces
Šulc, Václav ; Klapetek, Petr (referee) ; Ohlídal, Miloslav (advisor)
A Matlab numerical model for scattering simulation was proposed based on the solution derived from the Beckmann-Kirchhoff scalar theory of scattering of electromagnetic waves from rough surfaces. A series of various synthetic surface samples were obtained using the open source software Gwyddion on which numerical simulations of scattering were carried out. The validity of this numerical model was tested and compared with experimental results.
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Design of an imaging spectrophotometer for the spectral range 200-700 nm. Verification of the design in a laboratory set-up of the instrument
Doležal, Matěj ; Bouchal, Petr (referee) ; Ohlídal, Miloslav (advisor)
The bachelor thesis is devoted to the design and realization of laboratory setup of an imaging spectrophotometer for the spectral range 200–700 nm. In the introductory part of the thesis, an analysis of physical phenomena and quantities describing them is carried out which are important the given task solution. Research is made for imaging spectrophotometers that were implemented at the Institute of Physical Engineering BUT in the past. Attention was paid to the function and assembly of these devices. A substantial part of the work concerns the design of an imaging spectrophotometer with an angle of incidence of the light beam on the sample close to 90°, which would enable measurement in reflection and transmission mode. An analysis of the phenomena that influence the function of the given spectrophotometer is carried out. Based on this analysis, the design of the test set of the device is carried out. Subsequently, its implementation is described in detail, including the assembly procedure of the given spectrophotometer. Furthermore, the device is adjusted and, simultaneously, possibilities for improving the display quality are formulated. Then a test measurement of the thin layer prepared by plasma jet technology is performed. In the conclusion, the achieved results are summarized and ways to possible improvement of the functional imaging spectrophotometer are indicated.
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Use of finite element method for stress evaluation in layers for optical applications
Tesařová, Anežka ; Ohlídal, Miloslav (referee) ; Burša, Jiří (advisor)
This thesis is concerned with the mechanical stress generated in thin layers applied on a substrate. The application takes place at high temperatures and due to different coefficients of thermal expansion of materials, the sample is deformed, and thereby the stress is generated. The first part of the thesis includes the derivation of the Stoney formula for uniaxial and biaxial stress in a layer. Besides, analytical calculations of the normal stress in the layer for the simplified link model, and shear stress on the layer interface were evaluated. The main part of the work consists of solving the problem using FEM modeling. Because the actual temperature behavior during the application was not known, a fictitious temperature load was used as an input. For the samples, the coefficients of thermal expansion of the layer were then searched so that the thermal load resulting deflection corresponds to the experimental data. Three types of models were created, namely the link body model, the axisymmetric model, and the solid model. The axisymmetric model was used for the calculation of samples forming circular isolines during deformation and a volume model for samples forming elliptical isolines. The result of the FEM calculations was the normal stress in the applied layers, for which corresponding relationships were created using regression analysis.
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Modification of construction of the device for measuring laser light scattering from rough surfaces
Jaworková, Magdalena ; Klapetek, Petr (referee) ; Ohlídal, Miloslav (advisor)
This diploma thesis deals with a design modification of detection part of the laboratory instrument for measuring the topography of rough surfaces – laser goniometric scatterometer (SM II). Design modification is based on replacement of so far used detector instead for the detector of higher quality with better measurement parameters. The first part of the diploma thesis contains theoretical basics, which are necessary to understand the relationship between scalar diffraction theory and scattering measurements of monochromatic light. The emphasis is on the importance of choosing appropriate detection coordinates, which are affecting the aberrations of detected diffracted light. The practical part is dedicated to improving the sensitivity of the detection part of the scatterometer SM II that is used in The laboratory of coherence optics at IFE FME BUT. This part justifies the choice of the detector which predetermines both the use of optical elements and the overall design of the detection part as the goniometer.
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