Academic literature on the topic 'In-situ měření'

This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.

The doctoral thesis deals with usage of gel techniques for in situ measurement of bioavailable metals in soils and sediments. The DGT technique was applied to soil samples from the localities of Zlín, Tuřany and Chrlice for estimation of bioavailable metals in soils. These soils were amended by sewage sludges in years 1980-1987. The experiment using diffusive gels with different pore size, APA and RG gels, has shown that the DGT can be used for assessment of trace metal soil complexes - small inorganic and larger organic. The results obtained by DGT measurements were approximately up to two orders of magnitude lower than metal concentrations obtained by leaching with sodium nitrate. The leaching with sodium nitrate does not provide true reflection of metal availability to plant root system and soil microorganisms and the DGT technique seems to be a better predictor of metal bioavailability. Only small differences between undisturbed and homogenized soil samples were found out by application of DGT to soil samples from localities of Veverská Bítýška and Ostrovačice. The undisturbed soil is not homogenous and the DGT unit gives information only about the part of the soil which is in direct contact with the unit. The procedure with soil slurry can be recommended for the characterization of large soil areas and estimation of bioavailable metals in soils. Gel techniques were also used for the study of processes occuring in sediments. Mercury species and other metals were analysed in surface water, pore water and sediments collected from two sampling sites in the Dele River in northern France. This river had been polluted during the last century by the activity of Métaleurop factory, which dealt with metal ore treatment. The application of DGT technique using two specific ion-exchange resins, Chelex-100 and Duolite GT-73, provided assessment of mercury in sediment pore water. DGT and DET techniques together with centrifugation provided also high resolution depth profiles of Fe, Mn, Zn, Pb, Cr and Cd in pore water. It is not possible to determine which sampling site was more contaminated. Only small differences in mercury species and metal content were observed between sampling sites. The Dele River can be classified as contaminated river according to total mercury content in sediments and as slightly contaminated river from the point of view of methylmercury content. Correlations between mercury species and sulphide content confirm that total mercury and sulphide content count among factors influencing the mercury release to pore water and controlling processes of methylation and demethylation. Only low toxicity of sediment slurries was found out by the bioluminiscence test with Vibrio fischeri. The results of doctoral thesis demonstrate gel techniques as a very good tool in environmental analysis.

The work describes the design and manufacturing of a test device for post-mortem measurements of electrodes of electrochemical cells using X-ray diffraction spectroscopy. The theoretical part describes the diffractometer Rigaku Miniflex 600, for which the product is intended. At the same time, an overview of solutions in various applications is processed here in the form of a recherche. The practical part documents the current development of a new cell, on which tests were performed. Here is an overview of the influence of gases and insulating materials on the resulting data, especially distortion and attenuation. Subsequently, a new design with improved hermetic insulation and sample displacement error correction is described. The principle of operation of the manufactured cell, including the control unit and software, is elaborated in the form of technical documentation. Finally, the functionality is verified by comparing the diffractograms of the powder standards and the graphite electrodes.

The dissertation thesis is focused on thermal insulating properties of reflective insulation under boundary conditions typical for low-energy buildings. In the introductory part of this thesis the attention is focused on the heat transfer process. There is described primarily heat transfer by radiation. There is also described the reflective insulation and the methods of determination their thermal performance. The remaining part of the thesis deals with the analysis of the results obtained in experimental measurements. Measurement results are compared with the calculation model. Conclusions for technical practice including possibilities of further research are summarized in the final section.

This thesis deals with the software development to calibration and interpretation of image data measured by a LEEM device. As the imaging technique is uniquely suited for in-situ studies of surface dynamical processes, the attention is mainly paid to methods enabling the evaluation of measurement time series. The phase correlation method based on Fourier transform of images is proposed to temperature shift correction between consecutive frames. The thesis describes the methods of additive and impulse noise filtering, image visualization, the filtration of secondary electrons and the determination of I-V curves from measured image data. Implemented methods are described not only in terms of their mathematical origin, but also with emphasis on the revealing of critical aspects associated with their use. The thesis also focuses on the application of the created algorithm to image data capturing the spatial and temporal evolution of 4,4’-biphenyl-dicarboxylic acid surface phases induced by sample annealing. Based on these evaluations, a suitable procedure is then determined to perform accurate detection and compensation of temperature shift said.

Graphene is a material suitable for electronic applications including sensors and biosensors operating in atmospheric conditions and at varying relative humidities. This work concerns the charge diffusion in Hall bar shaped graphene based field effect transistor that is simultaneously investigated by Kelvin probe force microscopy and macroscopic transport measurement. Furthemore it studies the possibilities of graphene Hall bar modification by local anodic oxidation, local cathodic hydrogenation and mechanical lithography.

The masters thesis is about operational testing on selected constructions of a railway track „in situ“. There were selected two sections with and without under sleeper pads on a railway track for measurement. These measurements were evaluated then. The result is an assessment of the suitability or unsuitability for under sleeper pads for a rail transport.

The present PhD. thesis deals with the systems of building services (namely heating, ventilating and air conditioning, shading) which provide required indoor microclimate inside the immovable heritage. The work thus combines the exclusively technical field of building services (BS) and the general principles of heritage conservation. The aim of my PhD. thesis is the analysis of immovable heritage conservation processes, focusing on the current state of research and BS systems documentation. Furthermore the work concerns the possibilities of temporary measurements of indoor climate parameters inside the immovable heritage, and aims to develop a computer model (in BSim software) for the simulation of various working conditions in the selected buildings. For the stated aims were selected three representative historic houses: historical assembly hall at the Faculty of Civil Engineering, Brno University of Technology; the Palm Greenhouse at Lednice Chateau in Moravia; and Villa Tugendhat in Brno. These buildings had been surveyed for several years, and in this PhD. thesis I present their analysis, evaluation, and conclusions. The aims of this PhD. thesis broadly correspond to the transnational objectives. The present research is, for example, in accordance with the international document ICOMOS Charter (Zimbabwe, 2013) which is concerned with the analysis, conservation, and restoration of architectural heritage. The research of immovable heritage is also supported by European Union, e.g. by the Seventh Framework Programme of EU.

This thesis investigates the potential and limits of portable Raman spectrometers for their application in situ in the environment of museum collections. The data sets were obtained at the two locations. The first measurement took place in the Jewish Museum in Prague. Here we have studied stones from a silver Torah shield from the first half of the nineteen century. This shield is decorated with a set of precious and semi-precious stones and glass imitations. The shield originates from Poland and has been studied using two portable Raman spectrometers (785 nm and 532 and excitations). The second measurement took place in the premises of the Prague Loreto where we had available, at that time still unshown, objects of art for the forthcoming new exhibition. It was about jewelry like earrings, rings, bracelets and brooches, also about ordinary objects of daily use like mirrors, bowls and perfume bottles, or about the objects with religious themes, mostly crowns for the Virgin Mary and baby jesus. The obtained Raman bands correspond well with the reference values of the minerals, the deviation ranged in the order of +/- 3 cm-1 , which in general permits unambiguous identification of phases. Portable handheld Raman spectrometers working with a laser wavelength of 785 nm and 532 nm were able to quickly...

The aim of the thesis is to compare the results from in situ spectrometry and laboratory determination of the area activity of Cs-137 in samples taken from uncultivated soils. To fulfil the goal, the research question has been determined: Are the results from in situ measurement of the area activity of Cs-137 in uncultivated soil comparable with the results from laboratory measurement of collected soil samples? The theoretical part of the work has been written based on research of book publications, foreign scientific articles and electronic sources, which deal with the issue of radioactivity and its impact on the environment and the principle of semiconductor gamma spectrometry. The practical part of the work deals with the spectrometric measurement using in situ method and the laboratory determination of the area activity of Cs-137 in the soil samples using a semiconductor gamma spectrometer. The measurement and the soil sampling took place in the territory of the Šumava National Park and its adjacent areas in Pilsen Region. There were selected five locations (Nová Hůrka, Prášily, Srní, Nový Brunst and Hadí vrh). By in situ spectrometric measurement the highest values were determined of the area activity of Cs-137 in the location Nová Hůrka (19526 Bq / m2) and the lowest in the location Hadí vrh (5398 Bq / m2). The spectrometric measurements of the soil samples in the laboratory revealed the highest values of the area activity of Cs-137 in the sample from the location Nová Hůrka (10000 Bq / m2) and the lowest values of Cs-137 in the location Hadí vrh (2060 Bq / m2). The contribution of this work is the comparison of in situ spectrometric measurement with the measurement of taken soil samples using the gamma semiconductor spectrometer. The results of this monitoring can provide data on the radiation situation in individual locations in Šumava. By the comparison of the results of the area activity of Cs-137, there has been found a correlation between in situ spectrometric measurements and the laboratory measurements of the soil samples. The results of the area activity of Cs-137 are in an order of magnitude comparable. The differences between the results are probably caused by the measurement conditions.