National Repository of Grey Literature 54 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Study of catalytic oxidation of carbon monoxide by AFM/SEM
Hrůza, Dominik ; Janák, Marcel (referee) ; Bábor, Petr (advisor)
This diploma thesis focuses on the study of carbon monoxide oxidation on platinum using correlative AFM/SEM microscopy, which has been overlooked in the literature in this field of research. In the introduction is provided a description of the functioning of the used methods. Furthermore, the investigated reaction is theoretically explained, the oxides on platinum are described, and current directions of scientific research are discussed. The experimental part closely follows the theoretical section, where is described the transfer of the experiment between electron microscopes and the challenges associated with this transfer. This is followed by in-situ observations of the influence of ion beam modifications on the studied reaction. These measurements are compared by using electron and ion beams, and is provided a description of individual surface processes. The experimental results demonstrate new possibilities for influencing chemical reactions through surface modification and provide evidence supporting the theory of subsurface forms of oxides. Subsequently, the effects of the tip on the reaction are investigated, presenting the possibility of direct surface modification by engraving. In conclusion, time-resolved spectroscopy and surface mapping of the desorption reaction wave is carried out to elucidate the influence of the chemical wave passing under the tip. The thesis also includes surface spectroscopic analyses to support the conclusions drawn in this thesis.
Electron beam modification of nanostructure growth
Kilian, Jakub ; Voborný, Stanislav (referee) ; Bábor, Petr (advisor)
This bachelor's thesis focuses on the further development of a method for modifying the surface of germanium using alloy Au-Ge droplets. A focused electron beam, which is brought in close proximity to the droplet, is utilized for thermomigration-induced motion of the droplets. The thesis is divided into two parts. The first part is dedicated to explaining the fundamental principles that are essential for a proper understanding of the conducted experiments. The theoretical overview also includes an introduction to the individual instruments utilized in the experimental section. In the practical part, the movement of Au-Ge droplets and the resulting surface morphology left by the droplets' passage were initially examined. The remaining portion of the practical research concentrated on utilizing the focused electron beam for controlled growth of nanowires in the VLS process.
Study of catalytic reaction waves by SIMS
Jaroš, Antonín ; Willinger, Marc Georg (referee) ; Bábor, Petr (advisor)
Katalytické reakce jsou klíčové pro mnoho technologických oblastí. Abychom docílili jejich zlepšení, je potřeba porozumět jejich mechanismu, k čemuž je důležité vyvíjet nové in-operando techniky. Operando spektroskopie jsou obecně rozděleny do dvou kategorií: velkoplošné techniky, které poskytují zprůměrované informace z celé analyzované oblasti, přičemž nemusí zaznamenat signál z důležitých aktivních míst, a lokalizované techniky, které poskytují informace na atomární úrovni, ovšem nemusí relevantní aktivní místa obsahovat vůbec. V této práci je demonstrováno, že hmotnostní spektrometrie sekundárních iontů je bezprecedentní způsob, jak v reálném čase sledovat oscilační vlny během oxidace CO, poskytující mikro-spektroskopická data, která jsou klíčová pro rozluštění složitého katalytického mechanismu. Ukazuje se, že v nízkých tlacích jsou reakční vlny tvořeny střídajícími se vlnami oxidu platiny a adsorbovaného oxidu uhelnatého. Mechanismus reakce spočívá v redukci oxidu pomocí CO. Navíc jsou oxid platiny a CO adsorbáty nehomogenně rozloženy napříč vln, což je nejvíce patrné na reakční vlnoploše.
Real-time study of reaction waves
Gazdík, Richard ; Pavera, Michal (referee) ; Bábor, Petr (advisor)
Táto bakalárska práca sa zaoberá heterogénnou katalytickou oxidáciou oxidu uhoľnatého, a hlavne reakčnými vlnami vyskytujúcimi sa pri určitých podmienkach, na povrchu platiny. Práca je rozdelená na dve hlavné časti – teoretickú a experimentálnu. Teoretická časť podáva informácie ohľadom rastrovacieho elektrónového mikroskopu, mikroskopu atomárnych síl a detailov reakcie. Pre experimentálnu časť boli vykonané pozorovania tejto reakcie v ultravysoko-vákuovom, ako aj vo vysoko-vákuovom rastrovacom elektrónovom mikroskope, a v oboch prípadoch boli identifikované reakčné vlny. Cieľom bolo tiež skúsiť vykonať korelatívne meranie reakčných vĺn sondou a elektrónovým mikroskopom (CPEM), ktoré, bohužiaľ, z veľa rôznych dôvodov popísaných v poslednej časti práce, nevyšlo.
Three virtual characters in a quarrel: an interactive model
Babor, Petr ; Brom, Cyril (advisor) ; Beneš, Jan (referee)
In computer games, with the ambition to tell a story are often cut-scenes, passages of games, where the player does not play, but only follows a part of the narrated story. This fact distract player from playing. These passages should be integrated as much as possible in the game itself. The goal of our work is to design, implement and test a model for creating cut-scenes with dynamic development and limited user interaction possibilities. We restricted the model to a situation where three characters arguing and we implemented it for the Pogamut platform. We use animations and emoticons as means of expression, characters do not speak by natural language. Movement is ensured by the steering rules from the project Steering Library. Dramaturgy and synchronization of scenes is controlled by a stochastic finite state machine. We made an experiment where the test subjects watched the generated cut-scenes and compared them with hand-made to evaluate the work. The results confirmed the assumption that the quality of generated scenes do not reach handwritten ones. However the test subjects still perceived them positively, because of the ability to influence their development. Implemented parts of the model can be used to create games and educational programs with social theme. Theoretical design of the model can be...
Using genetic programming in robot evolution
Babor, Petr ; Mráz, František (advisor) ; Neruda, Roman (referee)
Artificial neural networks learned by evolutionary algorithms are commonly used to control the robots. Neural networks can be encoded either directly as a list of weights or indirectly as a weight generator. Unlike direct coding indirect encoding allows to encode a large network using a short genetic code. HyperNEAT is a neuroevolutionary algorithm, which encodes the neural network indirectly, through another (producing) network, which computes synaptic weights. A different algorithm called HyperGP is an alternative to HyperNEAT. In HyperGP, the producing network is replaced by an arithmetic expression, which is being evolved using a genetic programming (GP). We have designed enhancements for HyperGP, using techniques that are either known in a different context of GP or completely new. Algorithm and enhancements have been implemented and experimentally tested on a task of controlling virtual walking robot. The results were compared with HyperNEAT and with the original HyperGP. We have shown that most of the proposed enhancements are effective and, on the given task, HyperGP is better than HyperNEAT. GP thus can successfully replace NEAT in hyper-encoding scheme and improve its efficiency. Powered by TCPDF (www.tcpdf.org)
Study of CO oxidation on platinum by Auger spectroscopy
Hrůza, Dominik ; Voborný, Stanislav (referee) ; Bábor, Petr (advisor)
In the presented bachelor thesis, I deal with the study of the oxidation of carbon monoxide on platinum using Auger spectroscopy. In the introduction, I will describe the used methods. Furthermore, I theoretically describe the investigated reaction and indicate the measurements for a better understanding of the reaction. Then I will establish an experimental part, where I deal with the growth of graphene structures. This will be followed up by performing in-situ observations of the reaction with and without the presence of graphene. These measurements I compare and then analyse the surface composition during the reaction. Finally, I will create a methodology that can distinguish the individual molecules on the surface of the catalyst.
Study of CO oxidation on platinum by UHV-SEM
Jaroš, Antonín ; Kolíbal, Miroslav (referee) ; Bábor, Petr (advisor)
This bachelor’s thesis is focused on the study of heterogeneous catalytic oxidation of CO on the surface of platinum, but also in the confined space between platinum and graphene. The thesis is separated into two parts – theoretical and experimental. In the theoretical part, there is a general explanation of important principles regarding this thesis, such as the stucture of scanning electron microscope, growth of graphene, evolution of the catalytic oxidation of CO and oscillatory mode of this reaction, and lastly evolution of the same reaction under the graphene. The experimental part is chronologically concerned about individual tasks of bachelor’s thesis.
Correlative tomography
Vařeka, Karel ; Touš,, Jan (referee) ; Bábor, Petr (advisor)
Předložená diplomová práce se zabývá korelativním přístupem multimodální analýzy struktur prokovování s různým rozlišením. Výzkum je součástí mezinárodního projektu týkajícího se charakterizace poruch zmíněných struktur, které jsou implementovány v polovodičových zařízeních. Kombinace korelativní mikroskopie a tomografie technikami NanoXCT, FIB-SEM (EDS), FIB-SIMS a AFM byla navržena k zavedení opakovatelného pracovního postupu. Tomografie fokusovaným iontovým svazkem je metoda přesného odprašování v řezech, která mimo jiné v každém průřezu získává cenné snímky s vysokým rozlišením (FIB-SEM) nebo mapy chemického složení (FIB-SIMS). Následující transformace obrazu umožňuje identifikaci defektů jako funkci hloubky ve struktuře. Práce dále věnuje pozornost metodám sjednocení obrazů za účelem optimální prezentace získaných dat.

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