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Energy dispersive X-ray spectroscopy of doped PVDF fibers
Smejkalová, Tereza ; Papež, Nikola (referee) ; Sobola, Dinara (advisor)
Tato diplomová práce zkoumá flexibilní materiál k produkci elektřiny založený na piezoelektrickém polymeru Polyvinylidenfluorid (PVDF). Inkorporací piezoaktivní keramiky lze vlastnosti piezoelektrického polymeru PVDF významně zlepšit a převést na užitečnou elektrickou energii. PVDF byl vytvořen elektrostatickým zvlákňováním do vláken o tloušťce 1,5-0,3 µm a poté studován různými analytickými metodami. Tato práce nabízí popis elektrostatického zvlákňování, přípravu vzorků a teoretický úvod do analytických metod, kterým byly vzorky podrobeny. Morfologie a distribuce nanostrukturované keramiky do polymerní matrice PVDF byla pozorována použitím skenovací elektronové mikroskopie (SEM) a energiově disperzní spektroskopie (EDX). Pro tvorbu fáze a podrobné fázové složení byly vzorky charakterizovány infračervenou spektroskopií s Fourierovou transformací (FTIR). Práce také obsahuje analýzu s použitím Ramanovy spektroskopie, metody používané k identifikaci a porovnání chemických sloučenin. Elektrické vlastnosti byly studovány dielektrickou spektroskopií a je poskytnuta korelace se složením. Jednotlivé komponenty dotovaných vláken jsou charakterizovány a vyhodnocovány v souvislosti s jejich budoucím využitím v senzorech.
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Raman spectroscopy teaching equipment
Indra, Zdeněk ; Sedlák, Petr (referee) ; Škarvada, Pavel (advisor)
This thesis examines the principle of the Raman phenomenon and the function of the Raman spectrometer in order to build a low-cost Raman spectrometer assembly for school laboratory teaching. The thesis lists the important parts of the device and describes their key features. Subsequently, the selection of each component is discussed and a basic experiment is performed to verify the principle of this spectrometer. In the final part, a low-cost Raman spectrometer is constructed and tested thanks to the knowledge gained.
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Study of the morphology of highly oriented pyrolytic graphite irradiated by argon ions
Komínek, Josef ; Kaspar, Pavel (referee) ; Sobola, Dinara (advisor)
The main task of this bachelor’s degree work is study of highly oriented pyrolytic graphite (HOPG) using atomif force microscopy, Raman spectroscopy and XPS spectroscopy. HOPG is layered material: atoms in one layer have stronger bong between themselves than two atoms in two neighbouring layers. Wide application options require further study. HOPG is now commonly used in nano-industry. It is used as a dimension standard. HOPG of A quality was processed in this work. In order to get accurate 3D data of sample surface, AFM measuring was done. 3D models of surfaces of various sizes are made. For these purposes was used free AFM data tool. Height parameters are used to describe topography. Got parameters are important for further study.
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Designing and testing of new metal nanosubstrates for biomolecular sensors based on surface-enhanced Raman scattering (SERS) spectroscopy
Peksa, Vlastimil ; Procházka, Marek (advisor) ; Matějka, Pavel (referee) ; Richter, Ivan (referee)
Title: Designing and testing of new metal nanosubstrates for biomolecular sensors based on surface-enhanced Raman scattering (SERS) spectroscopy Author: Vlastimil Peksa Department: Institute of Physics of Charles University Supervisor: doc. RNDr. Marek Procházka, Ph.D., Institute of Physics of Charles University Abstract: This experimental methodical work was aimed at the optimization of selected gold and silver substrates and their use in construction of SERS-based biosensors, including following practical application. Several types of substrates, fabricated via a combination of bottom-up techniques on solid surfaces, were tested. The properties of these substrates were examined with probe molecules, namely methylene blue, porphyrins and tryptophan, on a confocal Raman microspectrometer. Obtained findings about the influence of analyte application, objective focusing and internal intensity standard were exploited for optimization of measurement procedures with regard to sensitivity, accuracy and reproducibility. A method for quantitative detection of food dye azorubine (E 122) in commercially available drinks was developed, based on these findings. Its results have shown its potential as a pre-scan method for field application and preliminary testing. Keywords: Metal nanosubstrates, biomolecules,...
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Structure and properties of DLC layers for industrial applications
Mates, Tomáš ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Fejfar, Antonín ; Marek, A. ; Vyskočil, J. ; Erichsen, J. ; Dawah, P.
Diamond-like carbon (DLC) layers based on amorphous carbon are used for wide range of applications, mostly for mechanical protection of various industrial components. We examined DLC layers at micro- and nanoscale by two independent microscopic techniques: Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) with a good agreement. We compared DLC layers grown on steel substrate and Si wafer and found similarly structured clusters and a certain difference in the density of nucleation centres. The measurements of local mechanical properties by the AFM tip revealed that the Si wafer behaves as softer material compared to the growing DLC nanoclusters that also exhibit lower values in the map of the relative local friction coefficient. Finally, we observed changes in the Raman spectra of the DLC exposed to annealing at ambient conditions and found a gradual shift from the diamond phase to the graphite phase as a function of increasing temperature.
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Identification of microbial pigments in evaporites using Raman spectroscopy: implications for astrobiology
Vítek, Petr ; Jehlička, Jan (advisor) ; Marshall, Craig P. (referee) ; Vandenabeele, Peter (referee)
Raman spectroscopy is a powerful tool for identification both inorganic and organic compounds including microbial biomolecules. Together with the fact, that it is considered to be the important nondestructive instrument for use on Mars within future robotic missions, it is necessary to assess its capabilities in scenarios relevant for both Martian and terrestrial conditions. In this work, the potential of Raman spectrometry was tested - including both bench-top laboratory systems as well as portable counterparts - to detect traces of life within evaporitic matrices through biomolecular identification. Due to their chemical and physical nature resulting in optical properties, pigments are important organic compounds in Raman spectroscopic analysis using visible excitation. Hence in this work we have focused on the Raman spectroscopic identification of pigments as biomarkers with relevance for investigation of life in both extreme terrestrial and potentially extraterrestrial environments. Results of methodical work are presented in Appendices I to III, dealing particularly with β-carotene as a model carotenoid pigment. The concentration limits of this biomarker in three different evaporitic matrices (halite, gypsum and epsomite) have been determined for artificially prepared powdered mixtures alone...
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Vibrational modes of nucleic acids components characterized by means of variable proton-deuterium exchange
Zoul, David ; Štěpánek, Josef (advisor) ; Šloufová, Ivana (referee)
Although the nucleon acid oscillatory spectra have been studied for a long period of time, many of oscillating modes have not been properly explained regarding their geometric sensitivity and weak binding. One of the possibilities how to acquire experimental data for interpretation of theese modes is to confront oscillating spectra of isotopes. The simplest is proton - deutron exchange. When molecules dissolve in heavy water they rapidly exchange the heteroatoms, but this is simultaneous for more stages, which leads to dynamic equilibrium state among various isotope forms. Statistic analysis of temporal progression of Raman spectra give us the possibility to analyze the spectra and to obtain unique experimental data. This technique is very promising for more complex nucleon acid segments to gain more structural information. This diploma thesis represents pilot study of introduced methodics. The objective is to implement adaptation of Raman spectrometr for given types of expiments and undertake first series of measurements. The results should clarify application bounds of proposed method refering to sensitivity, time constant of incident isotope exchange, severity of read-out in comparasion of achieved accuracy of the measurement.
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Femtosecond lasers and their applications
Oškera, Jakub ; Urban, František (referee) ; Münster, Petr (advisor)
Bachelor thesis deals with the definition of a laser, its properties and its use in practise. Work describes the basic principle of laser beam with associated individual laser types and comparison to conventional light radiation source. Next, work focuses on modes of transmission: continuous, pulse, and main differences among them. Next part describes femtosecond lasers and their generating pulses. The work contains theoretical design of measurements used for this particular laser. The theoretical concept is designed for the field of spectroscopy. The thesis mentions the basic methods of spectroscopy: ultravioletvisible, Raman and IR. Part of this work is also focused on WattJoule application software that has been programmed for the use in experimental measurement. This experimental measurement is described in the last part of this bachelor thesis. The purpose of the measurement is an attempt of connection of the laser beam into optical fiber. The conclusion discusses the description and outcome of this experimental measurement.
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Optical fibre sensors
Gallo, Martin ; Šifta, Radim (referee) ; Münster, Petr (advisor)
The aim of this thesis is to examine in detail the possibility of fiber as optical sensor. This work deals with optical fiber sensors, their distribution and use. Describes the most renowned types, their advantages and disadvantages. At the beginning of this thesis there is an introduction to optical fibers, description of well-known linear and nonlinear phenomena occurring in them, development of optical sensors. Sensors are cleraly divided by usage and common attributes. The paper focuses on distributed optical fiber sensors and includes two different designs of these sensors there are also basic principles in designing distributed sensors. At the end of the work, the sensor using Brillouin scattering measuring vibration is simulated in the simulation program. Viewed transmitted signal spectra are shown and conclusions of results are drawn.
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Optical amplifiers and their applications
Dvořák, Tomáš ; Havliš, Ondřej (referee) ; Münster, Petr (advisor)
The main purpose of this diploma thesis is to study of possibilities of optical amplification, ways of realization optical amplifiers and construction of operational EDFA amplifier . According to gained information and knowledge about optical amplifiers, the basic configuration of EDFA amplifier with posibility of connecting up to two EDFA modules, which uses erbium-dopped fibers for amplification, was made. There was also developed a 3D model of front control panel of the amplifier and placement of particullar items was planned. Next step was the construction of EDFA amplifier device and measuring of its parameters and features.
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