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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.
21

Nové přístupy k uspořádávání plasmonických nanočástic do 2D a 3D hybridních aktivních systémů pro SERS grafenu a SERS, SERRS a SERS + GERS aromatických molekul / New pathways to plasmonic nanoparticle assembling into 2D and 3D hybrid active systems for SERS of graphene and SERS, SERRS and GERS + SERS of aromatic molecules

Gajdošová, Veronika January 2019 (has links)
In the first part of the Thesis, a new type of active system for SERS and SERRS of hydrophobic molecules, namely a 3-dimensional (3D) nanosponge aggregate with incorporated hydrophobic molecules has been developed, and tested by fullerene C60 and hydrophobic free- base tetraphenylporfine (H2TPP). The SERS and SERRS (surface enhanced /resonance/ Raman scattering) limits of detection (LODs) of C60 at four excitation wavelengths spanning the visible spectral region were found to be by one order of magnitude lower than in the reference system, which mimics the previously reported ways of utilization of Ag nanosponges as substrates for SERS and SERRS. The superiority of the newly developed sample is attributed to the efficient localization of the hydrophobic molecules into hot spots in 2D fractal aggregates of Ag nanoparticles (NPs). Diprotonation of H2TPP during the procedure using HCl as the preaggregation agent has been eliminated by employment of NaCl. On the other hand, investigation of the mechanism of H2TPP protonation during the former preparation procedure opened a possibility to employ Ag nanosponge aggregate as nanoreactor. In the second part of the Thesis, 2D assemblies of AgNPs were found to be better substrates for SERS of single layer graphene (SLG) than the 3D ones. In particular, the 2D...
22

Paleogeografický vývoj kenozoických říčních systémů ve středních a severních Čechách a jejich vztah ke klimatickým změnám a neotektonice / Paleogeographic development of the Cenozoic river systems in the central and northern Bohemia and its link to climatic changes and neotectonics

Štor, Tomáš January 2018 (has links)
The main aim of this thesis is to provide greater details on the timing of the fluvial river systems formation in the middle and the northern Bohemia. We focused on the Ploučnice River and Vltava River evolution. The river systems are very complex therefore we have used multiple approaches of the research with the disciplines range from geology, sedimentology, geomorphology, geochemistry, over different dating methods such as 10Be and 26Al isochron burial dating, optically stimulated luminescence dating and radiocarbon dating methods. Our results suggests that the terraces are significantly older than previously proposed. The fluvial style of the Ploučnice River system changes from high-energy braided to long-bend meandered river in the upper terrace levels (36 to 29 m above the modern river) and from high- to medium-energy braided river in the middle terrace levels (22-14 m). In the lower terrace levels (13 to 5 m) high-energy braided to long-bend meandered river environments were identified. Terraces were dating at 34 m, 29 m and 14 m above the modern floodplain with cosmogenic radionuclides while the 19 m, 12 m and 6 m above the modern floodplain terraces were dating with OSL. The time span represented by the river terraces remains unclear and varies from Eburonian to Eemian (1.68 to 0.056 Ma)....
23

Vývoj nových fotoaktivních kationtových zirkonocenových komplexů / Development of novel photoactive cationic zirconocene complexes

Dunlop, David January 2021 (has links)
Title: Development of novel photoactive cationic zirconocene complexes Author: Bc. David Dunlop Department: Department of inorganic chemistry Supervisor: RNDr. Martin Lamač Ph.D. Advisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: Environmental concerns have brought about an unprecedented demand for sustainable energy sources among which electromagnetic radiation, light, currently dominates. Development of novel light- harvesting compounds and materials is at the forefront of current science, as it is essential to further our technological progress. This thesis contributes to the field by development of novel photoactive cationic group 4 metallocene complexes stabilized by pendant imine and pyridinyl donor groups, or N,O-donor aromatic ligands, as crystalline [B(C6F5)4]− salts. The complexes are prepared either by protonation of the intramolecularly bound imine moiety by PhNMe2H[B(C6F5)4] or by chloride ligand abstraction, by Li[B(C6F5)4]·2.5Et2O or in situ generated Et3Si[B(C6F5)4]. Prepared compounds were characterized by NMR spectroscopy. Solid state structures of the compounds were determined by X-ray diffraction analysis. The cationic complexes of Zr and Hf exhibited significantly enhanced luminescence which originates from triplet ligand-to-metal (3 LMCT) excited states with lifetimes of up to...
24

Mezioborové vztahy fyziky a chemie v přírodovědném vzdělávání / Interdisciplinary relations of physics and chemistry in science education

Konečný, Martin January 2016 (has links)
Title: Interdisciplinary relations of physics and chemistry in science education Abstract: This master's degree thesis deals with the topic of interdisciplinary relations of chemistry and physics in science education. According to the review, to conveniently integrate physics and chemistry the appropriate topics and approaches were selected. The thesis includes teaching materials and worksheets to the three topics (Evolution of the Universe and the Origin of Elements, Luminescence and Composition and Properties of Matter) that are suitable for integration of physics and chemistry. The teaching material "Evolution of the Universe and the Origin of the Elements" includes a study text for teachers and a shorter study text for pupils. The teaching material "Luminescence" is based on an independent research done by pupils with their own crafted UV-lamp, completed with the facts included in a powerpoint presentation. The teaching material "Composition and Properties of Matter" consists of three parts (The paraffin, The Candle and The Properties of Selected Organic Substances) and is designed for an independent research done by pupils. Listed study materials were checked by teachers during meetings and seminars. The thesis also includes an evaluation of listed study materials by an expert group of high school...
25

Detekce defektů solárních článků pomocí systému využívajcího elektroluminiscenci / System for electroluminiscence defect detection of solar cells

Marčík, Silvestr January 2017 (has links)
The master thesis focuses primarily on issues of photovoltaic cells in terms of their defects. The introductory part deals with the history of photovoltaics, their introduction into practice and finally an explanation of the photoelectric effect itself. The thesis also describes photovoltaic cells themselves. It explains their principle, advantages, disadvantages and the creation of photovoltaic systems. A substantial part of the work is focused on the topic of detection of defects using luminescent methods. Subsequently, it describes procedural defects arising from the improper handling of already manufactured products. The final part deals with the main topic of the work, which is a detection using luminescence methods and it also mentions the non-luminescence method LBIC. The practical part of the master thesis contains the analysis of the current solution and of the subsequent proposal of solution using a low cost camera. It describes how to modify the camera, verify its spectral sensitivity using a spectrometer and measure the sensitivity of the CMOS sensor. The conclusion is focused on verifying the functionality of the proposed solution on different sources of infrared radiation and photovoltaic panels themselves.
26

Detekce nánosu UV lepidla / UV adhesive coating detection

Pavelka, Radek January 2018 (has links)
This diploma thesis focuses on a design of camera control system used for detecting defects, appearing during a UV luminescent glue application on the bottom of a paper bag. As a part of this thesis, an application was developed, using Baumer VCXG-53C industrial camera, implementing two dierent control methods - 2D cross correlation image pattern matching based on previously user defined pattern and glue area size measuring based on binary segmented image. The result of this work is a fully developed control system, prepared to be put into operation at the customer’s production line.
27

Analýza fotovoltaických článků pomocí fotoluminiscence / Analyse of photovoltaic solar cells by the photoluminescence method

Richter, Vladimír January 2014 (has links)
This diploma thesis deals with the issues of photovoltaic cells. The main aim of this thesis is to introduce the principles of operation of solar cells and methods of detection of defects affecting their quality. The first part is about the functional properties of silicon cells and it also examines the possibilities of detecting the defects of these structures. It also describes the most commonly used modern diagnostic methods. In the next part, practical tests of photovoltaic cells using the methods electroluminescence and photoluminescence are performed. These methods are based on the excitation of luminescence radiation of the silicon material by the external light source.
28

Teoretická studie vlivu spin-orbitální interakce na spektra a fotofyziku rheniových komplexů / Theoretical study of spin-orbit coupling on spectra and photophysics of rhenium complexes

Heydová, Radka January 2017 (has links)
Title: Theoretical study of spin-orbit coupling on spectra and photophysics of rhenium complexes Author: RNDr. Radka Heydová Department: Physical and Macromolecular Chemistry Supervisor: Ing. Stanislav Záliš, CSc., JHI AS CR, v.v.i. Supervisor's e-mail address: stanislav.zalis@jh.inst-cas.cz Abstract: Relativistic effects, especially spin-orbit coupling (SOC), play an essential role in transition metal chemistry and SOC treatment is indispensable for a correct theoretical description. To demonstrate the importance of SOC, the energies and oscillator strengths of vertical transitions for a series of [ReX(CO)3(2,2'-bipyridine)] (X = Cl, Br, I) and [Re(imidazole)(CO)3(1,10-phenanthroline)]+ complexes were calculated in the spin-free (SF) and spin-orbit (SO) conceptual frameworks. Two different computational approaches were adopted: SO-MS-CASPT2 where SOC was added a posteriori using a configuration interaction model (SO-RASSI), and the approximate perturbative SO-TD-DFT method. Relativistic effects were included via the two-component Douglas-Kroll-Hess transformation and the zeroth-order regular approximation in the former and the latter technique, respectively. The SF (i.e. accounting only for the scalar relativistic effects) and SO results from both methods were compared with each other and to available...
29

Teorie a aplikace optické aktivity biomolekul / Theory and applications of optical activity of biomolecules

Krupová, Monika January 2021 (has links)
Title: Theory and Applications of Optical Activity of Biomolecules Author: Monika Krupová Supervisor: prof. RNDr. Petr Bouř, DSc. Institutions: Faculty of Mathematics and Physics, Charles University, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic Abstract: This thesis describes how we used several chiroptical spectroscopic methods to study chiral molecules: vibrational circular dichroism (VCD), circularly polarized luminescence (CPL) and magnetic circular dichroism (MCD). VCD and induced lanthanide CPL were used to study the structure of amyloid protein fibrils. We found out that VCD is very sensitive to their structure and supramolecular chirality. It could be used to distinguish between various polymorphic fibrils. On the other hand, induced lanthanide CPL provided information on the local structure. VCD was also used to study the hydration polymorphism of nucleoside crystals. Due to the crystal packing, the VCD signal was strong and specific for different types of crystals. Finally, electronic structure of hydrated Ln3+ ions was studied by MCD. Molecular dynamics simulations together with crystal field theory (CFT) and multistate complete active space calculations with second order perturbation correction (MS-CASPT2) were used to interpret the spectra. CFT...

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