|
|
Antennas for energy transmission along the car roof
Škoda, Adam ; Hebelka, Vladimír (referee) ; Vélim, Jan (advisor)
The presented master’s thesis deals with antennas transmitting energy along conductive materials. Surface waves are used for energy transmission. According to its properties, the horn antenna was chosen for the problem solution. This thesis includes the theoretical analysis of surface waves, waveguides and horn antennas. The concept of antennas includes the comparison of two different materials and two different frequencies. From the set of 8GHz antennas, the structure of two antennas where one wearing the other was chosen as the most suitable. The FoamClad material was also selected due to achievement of better parameters and properties then material CuClad. This structure was designed by two identical horn antennas where the energy between them is transmitted via slot. The suitable feeding and parallel plates were designed, and further the current structure was modified to SIW structure. The designed antenna was manufactured and its properties were measured for further comparison with simulation results. Furthermore, achieved differences between simulated and real antenna are discussed.
|
|
|
Photogeneration of Charge Carriers in Organic Semiconductors
Heinrichová, Patricie ; Kratochvílová, Irena (referee) ; Cimrová,, Věra (referee) ; Weiter, Martin (advisor)
The interest in the detail knowledge about elementary electronic processes during photogeneration of charge carriers, which allow achieving higher efficiency of organic solar cells, grows with advent of the commercial organic solar cells production. The thesis is focused on study of photogeneration of charge carriers in organic semiconductors, especially in -conjugated polymer materials. First part of the thesis summarized state of the art in studies of photogeneration of charge carriers in polymer solar cells. Subsequent experimental and results part are focused on study of polymeric solar cells prepared from electron donor polymers MDMO-PPV, Tg-PPV, PCDTBT and PCBTDPP and electron acceptor derivates of fullerenes PC60BM and PC70BM. Results of the thesis are divided in tree main parts: 1) study of charge transfer between electron donor and electron acceptor materials by optical methods, 2) study of charge transfer between electron donor and electron acceptor materials by optoelectrical methods and 3) development of organic solar cells on flexible substrates. The last part is focused largely on deposition methods of active materials thin layer.
|
|
|
Kinetics of photochromic reactions in thin polymeric layers
Zeman, Vojtěch ; Weiter, Martin (referee) ; Vala, Martin (advisor)
The thesis is aimed to the study of spiropyrane behavior in polymeric matrix of poly(N-vinylkarbazole) (PVK) and poly[2-methoxy-5-(3´,7´-dimethyloctyloxy)-1,4-fenylenvinylene)] (MDMO-PPV). The photochromic transformation of spiropyrane to its isomeric merocyanine form (SPMC) was studied by absorption and emission spectroscopy. It was found, that photochromic reaction is markedly dependent on the environment. In the PVK polymer, which don’t absorb in the visible region, a high yield of photochromic reaction was achieved. Both, absorption and emission spectrums were observed for this system. From the measurement of time dependencies of the fotochromic reaction, the activation energy of the reverse reaction was determined. A different behavior, particularly in emissive spectrums, was found for the MDMO-PPV polymer doped with spiropyrane. Instead of formation of new band of merocyanine, decrease of the polymer fluorescence was observed. Subsequently, we studied the interaction between the polymeric matrix and the photochromic spiropyrane using fluorescence quenching method. On the basis of energy transfer theory, a critical radius of the fluorescence quenching sphere in solution and in solid was determined.
|
|
|
In-car wireless power transfer
Cupal, Miroslav ; Polívka, Milan (referee) ; Raida, Zbyněk (advisor)
The thesis is focused on the design of antennas for wireless power transfer inside a car near the frequency of 8 GHz. In the last century, a number of scientists dealt with wireless transmission of energy with high power and long distances. Currently, attention is given to methods capable of transmitting energy with good effectively over a distance of meters for charging mobile devices, wireless sensors and other devices with low power consumption.
|
|
|
Flexible textile-integrated coils for inductive energy transfer
Konečný, František ; Cupal, Miroslav (referee) ; Raida, Zbyněk (advisor)
This work aims to describe the design of flexible textile coils in several variants (different coil dimensions, different designs). The parameters of the designed coils will be verified using simplified simulation models and compared with theoretical calculations. Further, the work deals with the practical design of coils, including the measurement of their basic parameters and determination the efficiency of inductive power transfer.
|
|
|
Analysis of powertrain systems of drilling equipment
Klíč, Zdeněk ; Pokorný, Přemysl (referee) ; Mergl, Václav (advisor)
This bachelor's thesis deals with powertrain systems of drilling rigs intended for construction work. The powertrain systems are divided according to the energy they used and then analyzed. This analysis includes a description of the important components in the systems, schematic images indicating the principle, a description of operations, power transfer, and specific examples of machines using each of the systems. The next part focuses on a summary of the pros and cons. The knowledge gained relates to modern drilling rigs with an emphasis on environmental friendliness. The result of the work is the generalization of this issue and the disclosure of a more detailed solution for individual systems.
|
|
|
Organic luminophores with long wavelenght emission
Kolaříková, Adéla ; Kratochvíl, Matouš (referee) ; Vala, Martin (advisor)
This bachelor thesis studies the possibility of achieving intense fluorescence in the red region of the spectrum using Förster resonance energy transfer (FRET) in nanoparticles. First, the optical properties of organic molecules that could be suitable for the creation of a so-called host-guest (HG) system consisting of an acceptor-donor pair were studied. The molecules studied were based on derivatives of diphenylstilbene containing the electron-donor group diphenylamine (DPA-DPS), which is linked to a differing electron-acceptor group via a -conjugated double bond system. The acceptor groups used, i.e., indandione (-IOO), vinyl ( V) and di(methoxycarbonyl)vinyl (-V(COOMe)2), differ from each other in structure and polarity, which was reflected by a change in the position of the fluorescence spectrum. In the HG systems studied, DPA-DPS-IOO always served as the guest (G1) and DPA-DPS-V and DPA-DPS-V(COOMe)2 always served as the host (H1 or H2). Nanoparticles from these substances (G1H1 and G1H2) were prepared by the nanoprecipitation method. FRET was observed for both of these systems. Upon excitation of the matrix, the energy was transferred to the guest G1, which subsequently fluoresced in the long-wavelength region. Furthermore, an increase in the quantum yield of the guest fluorescence was also observed for the nanoparticles formed from the G1H2 system, from 7% (powder) and 3.1% (nanoparticles) to 14% compared to both the powder form and nanoparticles formed from the guest alone. No increase in the quantum yield of guest fluorescence was observed for the nanoparticles of the G1H1 system. The results indicated that FRET can be an effective tool in developing nanoparticles exhibiting intense long-wavelength fluorescence for imaging.
|
|
| |
|
|
Flexible textile-integrated coils for inductive energy transfer
Konečný, František ; Cupal, Miroslav (referee) ; Raida, Zbyněk (advisor)
This work aims to describe the design of flexible textile coils in several variants (different coil dimensions, different designs). The parameters of the designed coils will be verified using simplified simulation models and compared with theoretical calculations. Further, the work deals with the practical design of coils, including the measurement of their basic parameters and determination the efficiency of inductive power transfer.
|
|
|
Quantum Coherence for Light Harvesting
Paleček, David ; Dědic, Roman (advisor) ; Jonas, David M. (referee) ; Polívka, Tomáš (referee)
Almost all life on Earth depends on the products of photosynthesis - the biochemical process whereby solar energy is stored as chemical-rich compounds. The energy of captured photons is transferred through a network of pigment-protein complexes towards the reaction center. The reaction center is responsible for trans-membrane charge separation, which generates a proton motive force which drives all subsequent biochemical reactions. The ultrafast (femtosecond) nature of the primary processes in photosynthesis is the main reason for its astonishing efficiency. On this timescale, quantum effects start to play a role and can appear in measured spectra as oscillations. It has been hypothesized that these are evidence of wave-like energy transfer. To unveil the fundamental principals of ultrafast excitation energy transfer in both natural and artificial light-harvesting systems, advanced spectroscopy techniques have been utilized. Coherent two- dimensional electronic spectroscopy is a state of the art technique which allows the most complete spectroscopic and temporal information to be extracted from the system under study. This technique has allowed us to identify a new photophysical process where the coherence of the initially excited state is shifted to the ground state upon an energy transfer step. Coherence...
|
guest ::
