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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.
11

Sledování vlivu teploty na vlastnosti lithium-iontové baterie / Electrochemical Properties of Lithium-Ion battery under Elevated Temperature

Kulíková, Barbora January 2019 (has links)
This Master’s thesis deals with a monitoring of the temperature influence on Li-ion batteries, literature search of this topic and proposal of experiments. First chapter contains the theory of evolution and fundamentals of the Li-ion batteries. Planned experiments with flow charts and block diagrams are described in the second chapter. The work station is explained along with a description of the execution of the experiments in the third chapter. The experiments are analyzed and results explained in the last chapter.
12

Vliv aditiv na vlastnosti elektrodových hmot pro alkalické akumulátory / Properties electrodes materials for alcaline accumulators

Řihák, Lukáš January 2009 (has links)
This thesis is involved in basical properties of electrode materials for alkaline accumulators. This thesis describes the possibilities of capacity stabilisation of nickel electrode to be stable for highest number of cycles. Thesis also consider modification of properties of electrode materials on the base of nickel hydroxide by using dopes (aluminum, manganese). Measuration proceeded on the thin film electrodes created by electrodeposition. Measuration of properties of electrodes proceeded by cyclic voltammetry and frequency analyzis.
13

Vliv iontů hliníku ve struktuře hydroxidu nikelnatého na vlastnosti elektrod / Influence of Al ionts in nickel hydroxide on behaviour of electrodes

Růžička, Tomáš January 2010 (has links)
This master's thesis is concerned with the influence of aluminate ions added in various concentrations into the structure of nicel hydroxide that creates Ni-Cd accumulators positive electrode active mass basis nowadays. Nicel hydroxide occurs in two basic modifications ? and ß. Nowadays used ß modification reaches low capacity in comparison with ? modification. The disadvantage of ? modification is its instability and gradual degradation to ß modification. The aim of this diploma paper is to select the optimal amount of aluminate additives into the structure of nicel hydroxide with regard to electrochemical efficiency, stability, and degradation degree of the accumulated layer.
14

Uhlíkové materiály pro elektrochemické zdroje elektrické energie / Carbon materials for power sources

Tichý, Jiří January 2011 (has links)
This work deals with carbon materials and using them in electrochemical energy sources. Object of this work was to prepare carbon materials and investigate their electrical properties. The theoretical part objects of the carbon materials, their properties, application in electrochemical energy sources and measurement methods used in experimental part. Experimental part describes the preparation of the electrodes with various carbon materials and summarizes the results of measurements.
15

Vliv LiOH na parametry alkalických akumulátorů / The LiOh influence in alkaline accumulators

Prchal, Jiří January 2011 (has links)
The deal of this thesis is study of the influence of LiOH added to electrolyte on Ni-Cd batteries. In theoretical part are analyzed properties of Ni-Cd accumulators in strong alkaline surroundings, especially with emphasis on structure changing of NiOH2 and NiOOH. In the second part of theoretical are also described methods for depositing Ni layers. In practical part electro-chemical spectrum and mass changing on Quartz crystal microbalance are measured by cyclic voltammetry method during charge/discharge process. The process of cation integration to the positive electrode structure in KOH, NaOH and CsOH electrolyte including related structural changes are observed.
16

Stabilita katodového materiálu pro LI-ion akumulátory / Stability of cathode materials for Li-ion accumulators

Janíček, Zdeněk January 2014 (has links)
This diploma thesis focuses on study of positive electrode materials for Li-Ion batteries. Our aim are intercalation materials whose are really perspective materials whose are widely used in this case. The theoretical part of my thesis focus on basic study of Li-ion batteries and their parameters. We studied charging and discharging processes. AFM and SEM were used as additional techniques for study LiCoO2 a Li0,975K0,025CoO2. We tested lifetime and stability of electrode as a perspective material for electrode for Li-ion batteries.
17

Studium jevů limitujících životnost sekundárních článků Ni-Zn / A Study of Phenomena that Limit the Life-Span of Ni-Zn Secondary Cells

Chladil, Ladislav January 2014 (has links)
This dissertation is focused on the study of selected additives and their effect on positive and negative electrodes of Ni-Zn secondary cells. The first group of additives consists of the inorganic compounds that reduce zinc oxide solubility and thus prevents shape changes of the zinc electrode. The second group contains organic additives that have the beneficial effect of dendrite growth prevention. All additives were examined in relationship to their compatibility with the positive electrode and to their effect on the zinc electrode dendrites inhibition, hydrogen evolution and corrosion inhibition. Moreover, the study of decomposition kinetics of supersaturated zincate solution with the first group of additives was performed. Finally, a short study of pulse regime charging mode with regard to dendrites inhibition was performed and evaluated.
18

Proportional slowing in old adults is modulated by episodic memory demands : an investigation of age-related slowing using compatible and arbitrary stimulus-response mappings / Proportional slowing in old adults is modulated by episodic memory demands : an investigation of age-related slowing using compatible and arbitrary stimulus-response mappings

Laubrock, Jochen January 2004 (has links)
Das dominante Datenmuster im Bereich des kognitiven Alterns ist der Alters-x-Komplexitätseffekt. Die vorliegende Studie untersucht, ob das Muster statt durch einen üblicherweise postulierten unspezifischen durch einen spezifischen Mechanismus erklärt werden kann: die mit dem Alter abnehmende Reliabilität episodischer Akkumulatoren. In sechs Reaktionszeit-Experimenten wurden junge und ältere Erwachsene verglichen, dabei wurden frühe kognitive (Stroop-Bedingung) und episodische Schwierigkeit (Reiz-Reaktions-Zuordnung) orthogonal manipuliert. Die vorhergesagte Dreifachinteraktion der beiden Faktoren mit dem Alter zeigte sich über die Experimente hinweg relativ konsistent. Eine modifizierte Brinley-Analyse ergibt deutlich unterschiedliche Steigungen der Regressionsgeraden im Alt-Jung-Raum für niedrige und hohe episodische Schwierigkeit. Als methodischer Beitrag wird im Anhang ein zur modifizierten Brinley-Analyse passendes Regressionsmodell entwickelt, das aus einigen einfachen Verarbeitungsannahmen folgt. Es wird gezeigt, dass in einer klassischen Brinley Metaanalyse die Steigung neben der theoretisch interessierenden Varianz von theoretisch uninteressanter Zwischen-Experiment-Varianz beeinflusst wird. / The age-by-complexity effect is the dominant empirical pattern in cognitive aging. The current report investigates whether a specific high-level mechanism---an age-related decrease in the reliability of episodic accumulators---can account for the age-by-complexity-effect, which is commonly assumed to be caused by an unspecific, low-level deficit. Groups of younger and older adults are compared in six reaction time experiments, using orthogonal manipulations of early cognitive difficulty (e.g., Stroop condition) and episodic demands (e.g., stimulus-response mapping). The predicted three-way interaction of age and the two factors was observed fairly consistently across experiments. A modified Brinley analysis shows that different regression slopes in old-young-space are required for conditions with low and high episodic difficulty. As a methodological contribution, a Brinley regression model following from certain simple processing assumptions is developed. It is shown that in contrast to a standard Brinley meta-analysis, the regression slopes in this model are not influenced by theoretically un-interesting between-experiment variance.
19

Alternativní zdroje energie se zaměřením na "Solární energetické zdroje v současné praxi" / Alternative Energy Sources with Focus on "Solar Energy Sources in Present Practice"

PECHA, Radim January 2007 (has links)
The thesis deals with the problems of alternative energy sources with focus on solar energy sources in present practice. The thesis introduction explains the reasons of the changes in the global fuel-energy balance and their adverse effects, characterizes individual alternative energy sources and their practical applicability. The main focus is on exploitation of solar energy. After explaining the principle of thermonuclear reactions as the source of energy in the Sun, the thesis analyses the question of production of photovoltaic cells and a solar module. It describes the types of commonly used accumulators, charges and voltage transformers. It points out all factors, which must be taken into account when handling solar panels in practice. In the last chapter, it in particular deals with the didactic instructions for teaching the topic of alternative energy sources at elementary schools, as well as the need for introduction of the mentioned topic to teacher colleges.
20

Sledování vlivu teploty na vlastnosti lithium-iontové baterie / Evaluation Of Temperature Influence on Lithium-ion Battery Properties

Zachová, Zuzana January 2020 (has links)
This diploma thesis deals with monitoring of the influence of temperature on the properties of lithium-ion batteries, especially on the safety and capacity of selected batteries. Chapters 1 and 2 contain a literature review on the subject, describing electrochemical energy sources, especially secondary accumulators, mainly lithium-ion cells. Furthermore, the safety and degradation processes of lithium-ion batteries are discussed and the third chapter describes the design of experiments, realization and outputs of these experiments.

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