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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Aplikace prekoncentračních/separačních technik pro stanovení platiny v životním prostředí atomovou spektrometrií / Application of preconcentration/separation techniques for the determination of platinum in the environment by atomic spectrometry

Kosárová, Hedvika January 2013 (has links)
This thesis deals with optimization of conditions for the determination of platinum by electrothermal atomic absorption spectrometry. The theoretical part describes the occurrence of platinum in different part of the environment, its physical and chemical properties, transport and bioavailability. There is also evaluated appropriate method for determination and preconcentration of platinum. The experimental part describes advance of optimize the measurement conditions for ETA-AAS, further is describes optimization of condition for SPE and work with real samples on which are applied this conditions.
142

Plazmochemická příprava a charakterizace tenkých vrstev na bázi hexamethyldisiloxanu / Plasmachemical deposition and characterization of hexamethyldiloxane thin layers

Blahová, Lucie January 2013 (has links)
Thin films have been used to modify surface properties of various materials for many years. Plasma Enhanced Chemical Vapor Deposition (PECVD) is one of the possible methods for their preparation and this technique is applied in this work as well. An organosilicone – hexamethyldisiloxane – is used as precursor. Thin films are created on the surface of the substrate using mixture of precursor and oxygen in radiofrequently excited capacitively coupled plasma. The aim of the thesis is to find the optimal deposition conditions for production of transparent thin layers with good barrier capabilities, low oxygen transmission rate especially. Thin film depositions were realized for different compositions of the deposition mixture in continuous and pulsed mode of plasma with varying supplied power and duty cycle values. The deposition process itself was monitored in situ by optical emission spectroscopy. Thin film coatings were analyzed to determine their physical chemical properties (infrared spectroscopy, surface energy) and barrier properties. Using optical emission spectroscopy, important particles were identified in the deposition plasma. Vibrational, rotational and electron temperatures were determined from relative intensities of chosen fragments. Composition of thin films was studied by infrared spectroscopy. The best results of oxygen transmission rate were achieved with layers prepared from deposition mixture with high oxygen content. It was possible to improve barrier properties by performing deposition in pulsed plasma mode with 20–30% duty cycle. In this diploma thesis, optimal deposition conditions of thin films from hexamethyldisiloxane with low oxygen transmission rate were determined. It is possible to use these results in practical applications, such as corrosion inhibitors for archaeological objects. Optionally, they can be used in various industry branches where it is desirable and feasible to prevent oxygen access to the material by deposition of barrier coatings.
143

Studium orgánů myší z inhalačních pokusů / Study of organs of mice in inhalation experiments

Vrlíková, Lucie January 2014 (has links)
The diploma thesis is devoted to study potential risks for living organisms resulting from inhalation of nanoparticles of chosen heavy metals. The main aim of this work is the investigation of organs from experimental white mice after their guided inhalation of lead nanoparticles. The samples of liver and lungs from these animals are taken in time periods during the inhalation experiments and processed by specific methods for their evaluation. After pressurized microwave assisted decomposition of selected samples of mice organs in high purity concentrated nitric acid the content of lead is determined by atomic absorption spectrometry with electrothermal atomization. Furthermore, the changes are monitored using the microscopy of histological slides stained with hematoxylin-eosin. The results of both approaches are evaluated and compared within the frame of this work.
144

Stanovení platinových kovů v půdách na území města Brna / Determination of platinum group metals in soils the city of Brno

Pavlíčková, Ivana January 2015 (has links)
The diploma thesis focuses on identifying the presence of platinum in soil samples by absorption spectroscopy. The work is divided into two parts, the theoretical part is focused on the occurrence and behavior of platinum in the environment, the fundamental chemical and physical properties of platinum, its importance in catalytic converters in cars, on solid phase extraction method and the method for the determination of atomic absorption spectrometry. The second part is the practical part, focused on the determination of the platinum amount in the soil samples in the city of Brno.
145

Stanovení tenzidů ve vodách pomocí separačních metod / Determination of tensides in waters by separation methods

Brestovská, Marta January 2015 (has links)
Surfactants are synthetically made surface-active agents contained in washing and cleaning products. They decrease the surface tension and remove dirt. Surfactants can be divided into three basic classes: anionic, cationic and non-ionic. Thanks to the massive use they penetrate into waste water and can disturb the environment. This diploma thesis deals with the occurrence of surfactants in water and their determination by separation methods, especially LC / MS.
146

Experimentální výzkum urychlovačem řízených jaderných reaktorů pro thoriovou jadernou energetiku / Experimental Investigation of Accelerator Driven Nuclear Reactors for Thorium Based Nuclear Power

Zeman, Miroslav January 2015 (has links)
The Master Thesis deals with the use of thorium nuclear fuel in accelerator driven systems. Basic principle of ADS, present situation and future possibilities are described in this work. The main goal of the work is determination of neutron flux in spallation target QUINTA. In December 2013, an experiment was performed at Joint Institute for Nuclear Research, Dubna. Samples of cobalt, situated at different positions in QUINTA target, were irradiated in secondary neutron field generated by deuteron beam of energies 2 AGeV and 4 AGeV and beam of C-12 with energy 2 AGeV. The samples were measured with the use of germanium semiconductor detectors and analysed using gamma-ray spectrometry. Reaction rates of Co-59 products were determined. Neutron flux was determined in setup QUINTA on the base of experimental reaction rates. Experimental reaction rates were compared with calcula1tion of MCNPX code.
147

Monitorování sněhové pokrývky metodou EIS pro možnost stanovení vodní hodnoty sněhu / Monitoring of the snow cover using EIS method for possibility of determining of the snow water equivalent

Novák, Michael January 2014 (has links)
The master´s thesis deals with snow cover monitoring especially in area Orlické mountains. For identification changes, which are related to variable loads on snow cover of temperature, humidity and gravity, has been selected indirect electrical method of measuring electrical impedance spectrometry. This method is described in the work and the results of monitoring are published in graphical form and are commented.
148

Zpracování a vizualizace dat z hmotnostního spektrometru typu TOF-MALDI / Data processing and visualization from the TOF-MALDI mass spectrometer

Kuba, Pavel January 2012 (has links)
This thesis describes the development of control applications for the deposition machine and mass spectrometer. Thesis describes operation principles of both devices and their hardware specifications. Thesis also describes the design of developed applications. Functionality was tested on series of real measurements.
149

Stanovení obsahu kadmia v rostlinném pletivu smrku ztepilého a buku lesního po aplikaci nanočástic oxidu kademnatého. / Determination of kadmium content in plant tissue of Norway Spruce and European Beech after application of cadmium oxide nanoparticles

Svozilová, Eva January 2017 (has links)
The aim of this thesis is to monitor cadmium content in needles of Norway spruce and European beech leaves after controlled exposure to cadmium oxide nanoparticles and evaluate the potential risks of such nanoparticles to plants. Needles and leaves were harvested after a one-week and two-week exposure and prior to analysis of cadmium content, they were modified using relevant procedures. Samples were mineralized in nitric acid using pressurized microwave mineralizer and subsequently analyzed by atomic absorption spectrometry (AAS) with electrothermal atomization of cadmium content. Based on the results AAS analysis the transport of nanoparticles into the plant tissue of studied species was evaluated, comparing the content of cadmium in one week and two weeks experiment in the washed and unwashed samples of needles and leaves.
150

Analýza složení a degradace léčivých látek a léčivých přípravků z 18. a 20. století / Analysis of the composition and degradation of pharmaceutical substances and pharmaceutical preparations from the 18th and 20th centuries

Kudláček, Karel January 2021 (has links)
The dissertation focused on the analysis of twenty historical remains of pharmaceutical substances and pharmaceutical preparations dating to the 18th and 20th century by liquid and gas chromatography with UV-spectrometric or mass spectrometric detection. The analytical approach was chosen with regards to the age and pharmaceutical forms of the analyzed historical remain. The authenticity of the sample was verified by identifying the active ingredients, their possible degradation products and other excipients by tandem mass spectrometry. The fragmentation of some analytes was also studied by tandem mass spectrometry. The stability of historical pharmaceutical preparations from the 20th century was assessed on the basis of a decrease in the concentration of active substances compared to the content declared by the manufacturer or, in case of historical pharmaceutical remains from the 18th century, on the basis of active substance concentrations determined in the historical residue and current reference material. A multi-analytical approach combining five analytical methods, the results of which complement each other, was used to analyze the historical remains of ointments. While the active substances identified in ipecacuanha were found to be partially degraded, they were completely degraded in senna...

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