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Molecular modelling - Structure and Properties of carbene-based catalyst
Kulovaná, Eva ; Zmrzlý, Martin (referee) ; Richtera, Lukáš (advisor)
Molekulové modelování umožňuje předpovídat chování nových látek a napomáhá při jinak obtížné interpretaci experimentálních dat. Záměrem našeho studia byla predikce vybraných vlastností polymeračních katalyzátorů na bázi karbenů, predikce jejich struktur a spektrálních charakteristik. K ověření chování karbenů a jejich prekurzorů ve formě chloridů byly studovány vybrané charakteristiky molekuly. Byla provedena vizualizace vybraných molekulových orbitalů a map elektrostatických potenciálů a elektronových hustot. Následně pomocí počítačových programů byly získány teoretické vazebné délky a úhly vybraných imidazolových a imidazolinových sloučenin a z nich připravených karbenů. Data strukturně podobných, již charakterizovaných sloučenin, byla získána z CCDC (Cambridge Crystallographic Data Centre) a následně konfrontována s námi vypočítanými daty. Byla změřena infračervená (IČ) a Ramanova spektra imidazolové soli a IČ spektrum příslušného karbenu. Tato spektra byla konfrontována s napredikovanými.
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Electrospun fibers based on PVDF and nylon
Černohorský, Petr ; Sobola, Dinara (referee) ; Papež, Nikola (advisor)
Polymer nanofibers used for the construction of triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) are new and promising technologies for energy recovery. Thanks to the generation of electrical energy based on mechanical movement (deformation), these fibers can find application in the field of self-powered electronic devices. In this work, three nanofibrous structures of materials were prepared by electrostatic spinning: pure polyvinylidene fluoride (PVDF), pure polyamide-6 (PA6) and their mixed combination PVDF / PA6. Non-destructive analyzes such as Raman spectroscopy, FTIR, XPS and electron microscopy were used to study the properties of nanofibers. Analyzes confirmed the positive effect of electrostatic spinning of polymers on the support of the formation of highly polar crystalline -phase in PVDF and , -phase in PA6. The structure arrangement of the nanofibrous material and their defects were observed by scanning electron microscopy (SEM). Furthermore, the contact angle of the wettability of the liquid on the surface was measured for the materials, and the permittivity was measured to monitor the dielectric properties. The described results make the mixed material PVDF / PA6 very promising for further research in the field of nanogenerators and functional textiles.
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Utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of PHA producing bacteria
Beránková, Barbora ; Enev, Vojtěch (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the study of the utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of polyhydroxyalkanoates (PHA) producing bacteria. Using gas chromatography with FID detection, we determined the polyhydroxybutyrate (P(3HB)) content of the PHA biomass of bacterial strains Burkholderia cepacia, Halomonas halophila, Cupriavidus necator H16 and its mutant strain Cupriavidus necator H16/PHB-4 and Lactobacillus delbrueckii, which is not a producer of polyhydroxyalkanoates but this bactrea was selected as representative of Gram-positive bacteria. Subsequently, thanks to Raman microspectroscopy, Raman tweezers and FT-IR spectrometer in combination with Raman FT-module, we were able to confirm or disprove the presence of P(3HB) in bacteria. Furthermore, the thesis describes Cupriavidus necator H16, which is a model organism for the production of P(3HB), and his mutant strain Cupriavidus necator H16/PHB-4. The bacterial strain Cupriavidus necator H16 was cultivated in a production mineral medium of various nitrogen contents, while cultivation was also carried out in liquid Nutrient Broth. By this cultivation we were able to reach various P(3HB) content in bacterial biomass, the spectra were subsequently compared with the spectrum of the bacterial strain Cupriavidus necator H16/PHB-4. Raman spectroscopy is well used to characterize the composition of individual bacterial cells, is a fast, versatile, and virtually non-invasive tool for studying cells.
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Design of the carbon atomic source for deposition of graphene in UHV
Čalkovský, Vojtěch ; Bábor, Petr (referee) ; Mach, Jindřich (advisor)
This bachelor's thesis deals with the design of the atomic carbon source for deposition of graphene layers in UHV conditions. In the first part are briefly described the problems of epitaxial growth, the theory of atomic beams and theory of sublimation. The second part is aimed on graphene description, namely on his properties and on the growth of graphene layers, especially by molecular beam epitaxy. The third part contains brief description of detection and analysis methods of carbon atomic beams. In the practical part of this bachelor's thesis the design and the numeric calculations were made in Simion 8.0 and EOD program. Afterwards the atomic carbon source was constructed. In the conclusion are discussed the obtained results.
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Selective hydrogenation/Oxidation of CVD graphene using AFM
Přikryl, Vojtěch ; Švarc, Vojtěch (referee) ; Bartošík, Miroslav (advisor)
Graphene is a perspective material for utilization in electronics due to its high charge carrier mobility. However, in order to be applicable in practice the bandgap opening is necessary. One way of achieving this is modification of graphene by hydrogenation or oxidation. This work concerns the possibility of using AFM for local hydrogenation/oxidation of graphene depending on the bias voltage between the tip and the sample. The presence of hydrogenation/oxidation was examined by Kelvin probe force microscopy and Raman spectroscopy. The possibility of oxidation was proved but hydrogenation was not proved.
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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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Raman spectroscopy of biologically active species and antitumor drugs
Třeštíková, Liběna ; Vetterl,, Vladimír (referee) ; Vrána, Oldřich (advisor)
SERRS spektra of biological materials are very komplex, because they consist of signals from all molecules present in cells. In this text are presented SERRS spektra of antitumor drugs and its komplex with DNA. Experimental are rated on doxorubicin and another antitumor druha and on study of theirs potential by treatment for tumors. Doxorubicin belong to clase antracycline antibiotics and is used for stop of tumor cells reproduction. Scientists found still new ways, new drugs. SERRS is one of possibilities for study of this drugs and theirs interaction with DNA.
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Molecular modelling - Structure and Properties of carbene-based catalyst
Kulovaná, Eva ; Hermanová, Soňa (referee) ; Richtera, Lukáš (advisor)
Pomocí molekulového modelování je možné předpovídat chování nových látek a napomáhá při jinak obtížné interpretaci experimentálních dat. Cílem práce byla predikce vybraných vlastností polymeračních katalyzátorů na bázi karbenů, predikce jejich struktur a spektrálních charakteristik a studie mechanismu polymerace za otevření kruhu laktidu. K ověření chování karbenů a jejich prekurzorů ve formě chloridů byly studovány vybrané charakteristiky molekuly. Byl proveden výpočet vybraných molekulových orbitalů a elektrostatických map. Následně pomocí počítačových programů byly získány teoretické vazebné délky a úhly vybraných imidazolových a imidazolinových sloučenin, karbenů a jejich možných produktů hydrolýzy. Data strukturně podobných, již charakterizovaných sloučenin, byla získána z CCDC (Cambridge Crystallographic Data Centre) a následně byla konfrontována s vypočítanými daty. Byla změřena infračervená a Ramanova spektra imidazolové soli a infračervené spektrum příslušného karbenu. Tato spektra byla konfrontována s napredikovanými. Pro lepší interpretaci spekter byla spočítána spektra možných produktů hydrolýzy. Následně byl studován mechanismus polymerace za otevření kruhu laktidu. Na základě spočítaných energií stacionárních bodů byl navržen nový mechanismus polymerace.
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Preparation of graphene layers by various methods and characterization of their properties
Zahradníček, Radim ; Bartošík, Miroslav (referee) ; Lišková, Zuzana (advisor)
This bachelor's thesis deals with the production of graphene by different methods. Graphene was prepared by mechanical exfoliation and chemical methods. Graphene oxide (GO) was first prepared by modified Hummers method and disolved the solution in isopropyl alcohol. It was subsequently reduced by photoreduction, UV radiation and thermal reduction. Produced graphene samples were characterized using optical microscopy, electron microscopy, atomic force microscopy, Raman spectroscopy and X$-$ray photoelectron spectroscopy. Measurement results and evaluation of production quality of graphene are shown in this work.
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Characterization of graphene electrical properties on MEMS structures
Brodský, Jan ; Pekárek, Jan (referee) ; Gablech, Imrich (advisor)
This work presents basic properties of graphene, methods for its synthesis and methods for its characterization by Raman spectroscopy, two-point probe, four-point probe and van der Pauw measurements. The experimental part of this work describes the process of graphene oxide, reduced graphene oxide and graphene sample preparation and measurement of its current-voltage characteristic by two-point probe method. Subsequently, sample annealing in vacuum furnace is described in this work. The annealing is important for acquiring good electrical contact between the 2D material and electrodes. Sample analysis by Raman spectroscopy is performed. The last chapters of this work describe design and fabrication of MEMS structure. Such structure serves for characterization of graphene and other 2D materials.
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