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Resposta da soja à aplicação de nitrogênio em sistemas de implantação em ambiente de várzea e modificações anatômicas em condições de hipoxia / Soybean response to nitrogen application in implantation systems in a lowland environment and modificatione modificações anatômicas em condições de hipoxiaHansel, Dâmaris Sulzbach Santos 28 February 2015 (has links)
Soybean has gained space in lowland areas. Where before had only irrigated rice, grows the interest for soybean, due to to rising issues on weed control and the interst for crop diversification in the same farm. However, the management used and the natural characteristics of lowland areas with rice cultivation collaborate for maintaining saturated soil in the field. Considering the cultivation of an upland crop, it is necessary that some management changes be done to benefit the establishment and development of the crop. In the first experiment different moments of broadcast Nitrogen (N) application were tested, in order to nurish the plant with the nutrient to help the biologic N fixation, that in saturated soils, is damaged. Also was used two seeding mechanisms, the conventional (offset double disc) and a mechanism that disrupts the compacted layer (planter shank) present in lowland soils. There was no difference between N application treatments. However, for the different mechanisms there was a difference in development and productivity, highlighting the planter shank. The second experiment was performed in the greenhouse also using cultivar TECIRGA 6070 RR, with the aim of observing anatomical modifications and their possible benefits among different time of saturation and vegetative stages. The aerenchymas were formed in the hypocotyl and roots, which were used as a survival mechanism by the plant when soil was saturated in the VC-V1 stage during six days, along with the adventitious roots. In the V6 stage, the aerenchymas showed better development, but due to tissue fragility and soil resistance, there was rupture of the atmospheric air conducting canals, formed by aerenchyma. This rupture occurred between the hypocotyl and the root, filling the canals with water and stopping the air conduction to submerged roots.In this stage the plant survived only with the support of the adventitious roots, formed on the plants hypocotyl. / A cultura da soja vem ganhando espaço nas áreas de várzea. Onde antes só havia o cultivo de arroz, cresce o interesse pela soja devido às dificuldades crescentes em relação ao controle de plantas daninhas e ao interesse pela diversificação de culturas. Porém, o manejo utilizado e as características naturais das áreas de várzea para o cultivo de arroz tornam difícil a drenagem. Em vista do cultivo de uma plantas em presença de lâmina de água, como a soja, é necessário que hajam algumas mudanças de manejo para beneficiar o estabelecimento e desenvolvimento da cultura. No primeiro experimento utilizou-se a cultivar TECIRGA 6070 RR e testou-se diferentes momentos de aplicação de nitrogênio (N) em cobertura, com o objetivo de fornecer à cultura o suprimento de N para auxiliar a fixação biológica de nitrogênio, que em ambientes saturados pode ser prejudicada. Também testou-se dois mecanismos de semeadura, o disco duplo e um mecanismo que rompe parte da camada compactada utilizando haste sulcadora, presente nos solos de várzea. Não houve diferença entre tratamentos de aplicações de N, possivelmente devido a não haver estresses hídricos. Porém para diferentes mecanismos houve diferença no desenvolvimento das plantas e na produtividade, destacando-se o mecanismo rompedor com haste sulcadora. O segundo experimento foi realizado em casa de vegetação utilizando também a cultivar TECIRGA 6070 RR, com o objetivo de mensurar modificações anatômicas e seus possíveis benefícios diante de diferentes tempos de saturação em diferentes estádios vegetativos. Os aerênquimas foram desenvolvidos no hipocótilo e raiz, os quais foram utilizados como mecanismo de sobrevivência pela planta quando o solo foi saturado no estádio VC-V1 durante seis dias, juntamente às raízes adventícias. No estádio V6 os aerênquimas apresentaram maior desenvolvimento, mas devido à fragilidade do tecido e resistência do solo, houve o rompimento dos canais de condução de ar atmosférico, formados pelos aerênquimas. Este rompimento ocorreu entre o hipocótilo e raiz, sendo inundado por água e cessando a condução de ar para pelos canais para as raízes submersas. Nesse estádio a planta teve a sua sobrevivência apenas com o auxílio das raízes adventícias, formadas no hipocótilo da planta.
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Etude pluridisciplinaire d'une hydrogénase : mécanisme et optimisation des propriétés catalytiques / multidisciplinary study of a hydrogenase : mechanism and optimization of catalytic propertiesAbou Hamdan, Abbas 06 November 2013 (has links)
Les hydrogénases sont des métalloenzymes qui catalysent la conversion réversible du dihydrogène en protons et en électrons. Durant ma thèse, je me suis focalisé sur certains aspects du fonctionnement de l’hydrogénase à [NiFe] hétérodimérique de Desulfovibrio fructosovorans. Nous avons montré que contrairement au mécanisme communément admis d’inactivation aérobie de l’enzyme, l’O2 n’est pas incorporé en tant que ligand au niveau du site actif mais agit plutôt comme un simple oxydant. Ce résultat remet en question le mécanisme proposé pour expliquer la tolérance naturelle à l’O2 de certaines hydrogénases. L’analyse à l’aide d’un modèle cinétique des voltamogrammes cycliques complexes obtenus avec 16 variants a montré que les vitesses d’(in)activation en conditions anaérobies peuvent être accélérées de plusieurs ordres de grandeurs. Nous avons aussi montré et expliqué la corrélation entre ces vitesses et la tolérance à l’O2. Nous avons étudié une série de mutants qui produisent H2 beaucoup plus lentement que l’enzyme sauvage. Nous avons montré que la vitesse de cette réaction est déterminée par celle de l’étape de diffusion du H2, qui est lente dans les mutants. Finalement, nous nous sommes intéressés à une thréonine appartenant à la voie putative de transfert des protons. Nous avons démontré que cet acide aminé est effectivement impliqué dans le transport des protons. Il joue aussi un rôle crucial dans la stabilisation des intermédiaires formés au cours du cycle catalytique et probablement dans la détermination des vitesses de transfert électronique et de diffusion à travers le canal. / Hydrogenases are metalloenzymes which catalyse the reversible conversion of dihydrogen into protons and electrons. In my work, I focused on some aspects of the catalytic mechanism of the heterodimeric NiFe hydrogenase from Desulfovibrio fructosovorans. We demonstrated that, contrary to the commonly accepted mechanism of aerobic inactivation, the attacking O2 is not incorporated as an active site ligand but rather acts as an electron acceptor. This finding calls for a re-examination of the mechanism for O2 tolerance of the natural O2 tolerant NiFe hydrogenases. We also described a simple analytical model that we used to analyse the complex voltammetric signals of 16 mutants obtained by substituting an amino acid near the active site. We demonstrated that this substitution can accelerate anaerobic inactivation and reactivation by up to three orders of magnitude. We also demonstrated and explained the correlation between these rates and O2-tolerance. We studied mutants whose H2-production activity is impaired. We found that the rate limiting step of this reaction is the diffusion of hydrogen out of the enzyme, through the hydrophobic channel. Finally, we focused on a threonine belonging to the putative proton transfer pathway. We demonstrated that this amino acid is indeed implicated in proton transport. It may also play a crucial role in the stabilization of intermediates formed during the catalytic cycle, and probably also in determining the rate of electron transfer and diffusion along the gas channel.
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Stanovení hodnoty společnosti O2 Czech Republic a. s. / The valuation of company О2 Czech Republic a.sSpálenský, Vít January 2015 (has links)
The aim of the diploma thesis is to determine the market value of the company O2 Czech Republic a. s. in time when was company acquired by PPF group (31.12.2013). The aim is evaluate deal in relation to expect rentability of this investment, in relation to shares market price and in relation to other similar transactions on communication market. Thesis include the valuation itself as well as the financial and strategic analysis. On this base is create financial plan on years 2014 - 2018. The actual valuation is performed using methods DCF Equity method, market valuation, and by comparable transactions method. In conclusion are evaluate deal conditions and impact on company business in the future.
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Etude de la gravure du SiN contrôlée a l'échelle atomique par implantation d'O2 suivi de gravure ultra-sélective SiO2/SiN en plasma déporté NF3/NH3 / Study of the etching of SiN controlled at the atomic scale by O2 implantation followed by ultra-selective SiO2 / SiN etching in remote plasma NF3 / NH3Soriano casero, Robert 25 January 2019 (has links)
Depuis le début de la microélectronique, l’industrie a développé sans arrêt des nouvelles technologies de gravure plasma pour diminuer la taille des dispositifs tout en réduisant le cout de fabrication et en augmentent les performances des circuits intégrés. Aujourd’hui, les transistors tel que le FDSOI 22nm ou FinFET 10 nm doivent être gravé avec une précision sub-nanométrique et sans endommager la sous-couche sur plus d’une couche atomique. Pour arriver à faire cela, de nouvelles technologie se développent, dont le Smart Etch. Cette technologie en deux étapes consiste à modifier la surface du matériau sous l’action d’un plasma, puis à retirer ce matériau modifié sélectivement par rapport au matériau non modifié. Le but de cette thèse est d’étudier la faisabilité de remplacer les plasmas de He et H2 utilisé dans le Smart Etch par des plasmas d’O2. L’intérêt est l’oxydation du matériau est une réelle modification chimique, permettant l’élimination sélective de ce dernier en RPS. Par ailleurs, contrairement aux plasma de He/H2, le plasma de O2 ne grave pas les parois du réacteur et rejette beaucoup moins d’impuretés dans le plasma. Dans un premier temps, nous avons étudié les mélanges gazeux NF3/H2 et NF3/NH3 utilisés dans l’étape de retrait RPS. Ces études ont été fait grâce à la spectroscopie d’absorption VUV et d’émission UV. Nous avons mis en évidence la création de HF dans les deux mélanges et nous avons mis en avant de manière indirecte la création de NH4F (cette espèce jouant un rôle clé dans la formation des sels) à partir de NH3 et HF. De plus nous avons observé la présence de F et H qui sont responsable de la gravure de SiO2 et SiN lorsque H2<NF3 et NH3<NF3. Dans un second temps, nous avons étudié par XPS angulaire et ellipsométrie l’implantation des ions oxygène dans du SiN avec différent flux et énergie ionique. Cela a bien montré que le SiN initial est transformé en une couche SiOxNy avec une contribution SiO2 importante, sous réserve que l’état stationnaire soit atteint (il faut une dose d’ions significative pour cela). Le flux, l’énergie des ions et le temps de traitement sont donc les paramètres clés pour le contrôle de la couche modifié. Enfin, des tests préliminaires de gravure cyclique de SiN pleine plaque en mode « ALE » (c’est dire monocouche atomique par monocouche atomique) ainsi qu’en mode standard (retrait de quelques nanomètres / cycle) montrent que le principe de gravure est réaliste. Ce travail ouvre donc la voie au développement de ce nouveau type de procédé. / Since the beginning of microelectronics, the industry has continuously developed new plasma etching technologies to reduce the size of devices while reducing the cost of manufacturing and increase the performance of integrated circuits. Today, transistors such as 22nm FDSOI or 10nm FinFET must be engraved with sub-nanometric precision and without damaging the underlayment on more than one atomic layer. To achieve this, new technologies are developing, including the Smart Etch. This two-step technology involves modifying the surface of the material under the action of a plasma and then removing selectively the modified material from the unmodified material. The aim of this thesis is to study the feasibility of replacing the He and H2 plasmas used in the Smart Etch by O2 plasmas. The interest is the oxidation of the material, that it is a real chemical modification, allowing latter the selective elimination by RPS. Moreover, unlike He / H2 plasma, the O2 plasma does not damage the reactor walls and releases much less impurities into the plasma. Firstly, we studied the gaseous mixtures NF3 / H2 and NF3 / NH3 used in the step of RPS remove. Thouse studies were done through VUV absorption spectroscopy and UV emission. We have demonstrated the creation of HF in both mixtures and we have indirectly highlighted the creation of NH4F (this species plays a key role in the formation of salts) from NH3 and HF. In addition we observed the presence of F and H which are responsible for the etching of SiO2 and SiN when H2 <NF3 and NH3 <NF3. Secondly, we studied angular XPS and ellipsometry by implanting oxygen ions in SiN with different flux and ionic energy. This has shown that the initial SiN is transformed into a SiOxNy layer with a significant SiO2 contribution, provided that the stationary state is reached (a significant dose of ions is required for this). Flux, ion energy and processing time are therefore the key parameters for controlling the modified layer.Finally, preliminary tests of full-plate SiN cyclic etching in "ALE" mode (ie atomic monolayer by atomic monolayer) as well as in standard mode (removing a few nanometers / cycle) show that the etching principle is realistic. This work opens the way to the development of this new type of process.
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Mécanismes physico-chimiques dans le procédé de gravure plasma du SiliciumMellhaoui, Xavier 24 May 2006 (has links) (PDF)
Dans l'industrie de la microtechnologie, la gravure profonde du silicium permet l'obtention de structures à fort rapport d'aspect (MEMS, MOEMS, vias, caissons d'isolation...). La cryogravure est l'une des voies pour réaliser ces structures. L'objet de cette thèse est l'étude des mécanismes de formation de la couche de passivation SiOxFy dans le procédé cryogénique de gravure par plasma SF6/O2 du silicium. Cette couche ne se forme uniquement qu'à basse température (~ -100°C). Elle désorbe lors de la remontée en température à l'ambiant du substrat en libérant des espèces analysables par spectrométrie de masse. La principale espèce détectée est le produit de gravure SiF4. En testant des plasmas de construction de la couche avec le SiF4, nous avons trouvé deux mécanismes possibles de formation de la couche SiOxFy. Afin de compléter l'étude, nous avons installé un ellipsomètre spectroscopique in-situ afin de caractériser l'interaction de différents plasmas (Ar, SF6, O2, SF6/O2, SiF4/O2) avec le silicium montrant ainsi l'effet de la température du substrat et du flux d'ions.<br />En régime de surpassivation, les MicroStructures Colonnaires, défaut du procédé de cryogravure, apparaissent au fond du motif. Une étude paramétrique de ces structures est effectuée en variant les conditions du plasma (température, Vbias, puissance de la source, pression et temps).
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Effets de température dans les procédés de gravure plasma : Aspects fondamentaux et applicationsKoo, Min 22 December 2008 (has links) (PDF)
L'objectif du travail de thèse est d'étudier les effets de température et du dopage sur les caractéristiques de gravure du Si et des polymères : produits de réaction, cinétiques, énergie d'activation, anisotropie, et sélectivité. La gravure anisotrope des polymères est ensuite étudiée en fonction de la température en utilisant des mélanges de gaz permettant d'utiliser un procédé par passivation latérale. Les résultats expérimentaux obtenus sont discutés en tenant compte de l'étude thermodynamique des systèmes chimiques concernés. Le travail s'achève par l'étude de faisabilité de filtres pour microfiltration par perçage de pores à travers des films polymère.
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Controle da lanosidade, em pêssegos chiripá , com o uso de atmosfera controlada e etileno / Control of mealiness, in chiripá peach fruits, using controlled atmosphere and ethyleneGiehl, Ricardo Fabiano Hettwer 11 September 2006 (has links)
Experiments were performed aiming to study the effect of controlled atmosphere (CA) and exogenous ethylene treatment on both the post-storage ripening and mealiness
(woolliness) occurrence, evaluated both visually and objectively by the free juice content in the flesh of Chiripá peach fruits. Furthermore, the effect of inhibiting the ethylene action either in the beginning or in the end of CA storage on the incidence of physiological disorders and on the physical and chemical quality were also evaluated. In the first experiment, carried out both in 2005 and 2006, we evaluated: [1] cold storage (CS 21.0 kPa O2 + <0.5 kPa CO2); [2] CA with 1.0 kPa O2 + 3.0 kPa CO2; and [3] CA with 2.0 kPa O2 + 8.0 kPa CO2. In 2005, fruits were stored during 25, 30, and 35 days at -0.5°C, whereas in 2006, storage was prolonged until 40 days. The second experiment evaluated the effect of exogenously applied ethylene in the storage room. The storage conditions were: [1] CS; [2] CS + exogenous
ethylene (≈20 μL L-1); [3] CA (1.0 kPa O2 + 3.0kPa CO2); and [4] CA + exogenous ethylene. In the third trial, the effect of the ethylene action was assessed by the application of 1-
methylcyclopropene (1-MCP - 900nL L-1), a potent inhibitor of the ethylene action. The treatments studied were: [1] CS + 1-MCP; [2] CA (2.0 kPa O2 + 8.0 kPa CO2); [3] CA + 1-
MCP applied during the first 24 h of storage (P1); and [4] CA + 1-MCP applied during the first 24 h of post-storage ripening at 20°C (P2). As the storage period was increased, the free
juice contents decreased, independently of the storage condition. The flesh juiciness decreased sharply until 2 days of post-storage ripening at 20°C, but increased again thereafter. This free juice restoration was both a storage period- and a storage condition-dependent process. CAstored
fruits, especially in 2.0 kPa O2 + 8.0 kPa CO2, restored free juice contents faster. However, CS-stored fruits showed an abnormal pattern of ethylene synthesis, as the storage
period was prolonged, a behavior that possibly led these fruits to restore their free juice contents to a lesser extend. Ethylene treatment during CS enhanced post-storage ethylene
production and allowed fruits to restore juiciness at the same level as CA did. In addition to the ability of fruits in synthesize ethylene and to the effect of the presence of this gas, the
ethylene action, during the post-storage ripening, was critical for the process of free juice restoration to occur. The application of 1-MCP, in the beginning of the CA storage, is the most promising technique for storing Chiripá peach fruits, because it allows both physical and chemical quality maintenance and avoids the dramatic decrease of flesh juiciness at the 2nd day after storage / Foram conduzidos experimentos objetivando avaliar o efeito da atmosfera controlada (AC) e da aplicação exógena de etileno sobre o amadurecimento e a ocorrência de lanosidade,
avaliada visualmente e objetivamente pelo conteúdo de suco livre na polpa, em pêssegos Chiripá , após o armazenamento. Além disso, estudou-se o efeito da inibição da ação do
etileno em dois momentos, no início e no final do armazenamento em AC, sobre a ocorrência de desordens fisiológicas e a qualidade físico-química dos frutos. No primeiro experimento, realizado em 2005 e 2006, avaliou-se: [1] o armazenamento refrigerado (AR 21,0kPa O2 +<0,5kPa CO2); [2] a AC com 1,0kPa de O2 + 3,0kPa de CO2; [3] e a AC com 2,0kPa de O2 + 8,0kPa de CO2. Em 2005, os frutos foram armazenados durante 25, 30 e 35 dias; e, em 2006,
durante 40 dias. As análises foram realizadas, em ambos, na saída da câmara e aos 2, 4 e 6 dias a 20°C. No segundo experimento, avaliou-se o efeito da presença do etileno exógeno no ambiente de armazenamento, sendo: [1] AR; [2] AR + etileno exógeno (≈20μL L-1); [3] AC (1,0kPa de O2 + 3,0kPa de CO2); e [4] AC + etileno exógeno. No terceiro experimento, estudou-se o efeito da inibição da ação do etileno, pela aplicação de 900nL L-1 de 1-
metilciclopropeno (1-MCP), sendo: [1] AR + 1-MCP; [2] AC (2,0kPa de O2 + 8,0kPa de O2); [3] AC + 1-MCP aplicado nas 24 horas iniciais do armazenamento (P1); [4] AC + 1-MCP
aplicado nas primeiras 24 horas iniciais da exposição a 20°C, após o armazenamento (P2). Os conteúdos de suco livre diminuíram à medida que o período de armazenamento foi
aumentado, independente da condição utilizada. Durante o amadurecimento pósarmazenamento, a suculência decresceu drasticamente até o 2º dia, mas aumentou novamente a partir do 4º dia. Esse restabelecimento dos conteúdos de suco livre foi dependente do período e da condição de armazenamento utilizada. Os frutos armazenados em AC, especialmente em 2,0kPa de O2 + 8,0kPa de CO2, restabeleceram mais rapidamente a suculência. Por outro lado os frutos do AR apresentaram um padrão anormal de síntese de etileno com o aumento do período de armazenamento, o que, provavelmente, impediu esses frutos de restabelecer satisfatoriamente seus conteúdos de suco livre na polpa. A aplicação de etileno exógeno, durante a conservação em AR, estimulou a síntese de etileno e permitiu um
restabelecimento mais pronunciado da suculência dos frutos, em relação ao AR. Além da capacidade de síntese e da presença de etileno, a ação desse fito-hormônio, no período de amadurecimento pós-armazenamento, demonstrou ser fundamental para o restabelecimento dos níveis de suco livre na polpa. A aplicação de 1-MCP no início do armazenamento em AC demonstrou ser a mais promissora para o armazenamento de pêssegos Chiripá , por manter a
qualidade físico-química dos frutos e evitar a acentuada redução da suculência nos primeiros dias que sucedem ao armazenamento
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Simulations aux grandes échelles de la phase d'allumage dans un moteur fusée cryotechnique / Large eddy simulations of the ignition phase in a cryogenic rocket engineRocchi, Jean-Philippe 12 September 2014 (has links)
À ses débuts, la conquête spatiale a pu bénéficier des rivalités politiques de la Guerre Froide pour se développer rapidement sans réellement se soucier des efforts économiques à fournir. Aujourd’hui, de nombreux pays subissent le revers de la médaille de cette course effrénée : pour maintenir une flotte de lanceurs viable économiquement, les différentes agences spatiales doivent faire face à un dilemme opposant la minimisation des coûts de lancement à la maximisation de leur fiabilité. Dans cette logique d’optimisation, les industriels présents dans ce processus de réflexion se tournent vers la simulation numérique pour tenter d’améliorer leurs connaissances des technologies existantes, en particulier sur les zones d’ombres inaccessibles aux mesures expérimentales. Dans la lignée de plusieurs études théoriques et expérimentales, ces travaux visent à apporter un éclairage nouveau sur les phénomènes se produisant lors de l’allumage d’un moteur fusée cryotechnique. Ces recherches se tournent dans un premier temps vers l’amélioration de la modélisation de la flamme H2/O2. La validation d’une cinétique chimique réduite initialement destinée à la combustion H2/Air permet de justifier son utilisation lors de l’allumage. Puis, le développement d’un modèle de combustion turbulente pour le régime de flamme de diffusion est mené dans le but de palier aux limitations du modèle de flamme épaissie. Enfin, une analyse du cas où les régimes prémélangés et non-prémélangés sont présents tous les deux permet d’étudier un moyen simple de les distinguer même dans le cas où ils sont très proches. Dans un second temps, ces travaux se tournent vers l’étude de l’allumage dans un moteur fusée cryotechnique. Après avoir analysé de manière globale le calcul d’une séquence simplifiée, deux études plus approfondies sont menées pour investiguer, d’une part, les différents régimes de combustion, et d’autre part, les différents modes de propagation de la flamme propres à cette configuration. / The beginning of the conquest of space received benefits from the political competition of the Cold War and consequently grow quickly without considering the cost of these advances. The end of this unrestrained technological race brings to light the other side of the coin. In order to keep a fleet of launch vehicles up-to-date with the market, spatial agencies must answer a question : how can the cost of a launch be reduced without decreasing its efficiency. Through the use of numerical simulation, industrial partners may investigate this logic of optimisation. This solution might provide improvement in the knowledge of existing technologies, especially when experimental measurements are impossible. Following the path of theoretical and experimental results, this study aims to present a new view about the different processes occurring during the ignition of a space rocket engine. First, this research will present an improvement of the modelling of H2/O2 flame. The validation of a reduced chemical scheme basically developed for H2/Air will justify its use during the ignition sequence. Then, a turbulent combustion model for non-premixed flames will be developed in order to compensate the limits of the thickened flame model implemented in AVBP. Additionally, a study of both premixed and non-premixed regimes in a closed position will bring a simple method to distinguish them for a further active use. Secondly, this research will study the ignition process of a representative cryogenic space rocket chamber. The calculation of a simplified ignition sequence will be globally investigated. Finally, two-detailed analysis will lead to different combustion regimes and flame spreading processes
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Architectural Nanomembranes as Cathode Materials for Li-O2 BatteriesLu, Xueyi 31 August 2017 (has links) (PDF)
Li-O2 batteries have attracted world-wide research interest as an appealing candidate for future energy supplies because they possess the highest energy density of any battery technology. However, such system still face some challenges for the practical application. One of the key issues is exploring highly efficient cathode materials for Li-O2 batteries.
Here, a rolled-up technology associated with other physical or chemical methods are applied to prepare architectural nanomembranes for the cathode materials in Li-O2 batteries. The strain-release technology has recently proven to be an efficient approach on the micro/nanoscale to fabricate composite nanomembranes with controlled thickness, versatile chemical composition and stacking sequence.
This dissertation first focuses on the synthesis of trilayered Pd/MnOx/Pd nanomembranes. The incorporation of active Pd layers on both sides of the poor conductive MnOx layer commonly used in energy storage systems greatly enhances the conductivity and catalytic activity. Encouraged by this design, Pd nanoparticles functionalized MnOx-GeOy nanomembranes are also fabricated, which not only improve the conductivity but also facilitate the transport of Li+ and oxygen-containing species, thus greatly enhancing the performance of Li-O2 batteries. Similarly, Au and Pd arrays decorated MnOx nanomembranes act as bifunctional catalysts for both oxygen reduction reaction and oxygen evolution reaction in Li-O2 batteries. Moreover, by introducing hierarchical pores on the nanomembranes, the performance of Li-O2 batteries is further promoted by porous Pd/NiO nanomembranes. The macropores created by standard photolithography facilitate the rolling process and the nanopores in the nanomembranes induced by a novel template-free method supply fast channels for the reactants diffusion. In addition, a facile thermal treatment method is developed to fabricate Ag/NiO-Fe2O3/Ag hybrid nanomembranes as carbon-free cathode materials in Li-O2 batteries. A competing scheme between the intrinsic strain built in the oxide nanomembranes and an external driving force provided by the metal nanoparticles is introduced to tune the morphology of the 3D tubular architectures which greatly improve the performance by providing continuous tunnels for O2 and electrolyte diffusion and mitigating the side reactions produced by carbonaceous materials.
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Management firmy v globálním prostředí / Managing a Firm in a Global EnvironmentStaňková, Lenka January 2017 (has links)
This master thesis focuses on the process of globalization and its consequences that allowed for the formation of multinational corporations. The current environment is characterized by the fast pace of changes that requires firms react flexibly, which demands new approaches to managing employees, creating more flexible organizational structures supporting creative people, and innovation because people and innovations are the key sources of competitive advantages. The goal of this thesis is to analyze changes at O2 after Spanish telecommunications firm Telefónica S.A. sold a majority stake to PPF in 2013. The changes associated with the switch in ownership can chiefly be seen in the firm's goals, its organizational structure, its policy toward employees, in customer satisfaction, and in its investments and share price.
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