Spelling suggestions: "subject:"forenergy"" "subject:"aboutenergy""
441 |
Recherche de nouvelle physique à basse énergie à l’aide de théories efficacesHamoudou, Serge 07 1900 (has links)
L’existence de physique au-delà du modèle standard semble de plus en plus évidente, notamment en raison d’observations d’anomalies dans plusieurs phénomènes. De plus, certains phénomènes tels que la matière noire, la gravité et l’asymétrie baryonique dans l’univers sont inexpliqués. Ce mémoire s’intéresse à la recherche de nouvelle physique à basse énergie par l’approche des EFT et se penche sur les prédictions à basse énergie d’une EFT en particulier : la SMEFT. Le premier article présenté s’intéresse aux anomalies présentes dans les données expérimentales liées aux mésons B et teste les prédictions de la SMEFT pour la désintégration b → cτν jusqu’à la dimension massive 6. Le but est de vérifier si la symétrie du modèle standard, soit SU(3)_C × SU(2)_L × U(1)_Y, est réalisée linéairement à haute énergie par la nouvelle physique. Le deuxième article détermine les relations de correspondance entre les opérateurs LEFT jusqu’à la dimension massive 6 et les opérateurs SMEFT jusqu’à la dimension massive 8. / The existence of physics beyond the Standard Model seems more and more obvious, partially because of observations of anomalies in many phenomena. Moreover, some phenomena such as dark matter, gravity and the baryon asymmetry in the universe are unexplained. This thesis addresses the search of New Physics at low energies using the EFT approach and looks into the predictions of low-energy predictions of one EFT in particular: SMEFT. The first paper presented addresses anomalies present in experimental data related to B mesons and tests the predictions of SMEFT for b → cτν decays up to mass dimension 6. The goal is to check if the Standard Model symmetry, being SU(3)_C × SU(2)_L × U(1)_Y, is linearly realized at high energy by the New Physics. The second paper determines the matching conditions between LEFT operators up to mass dimension 6 and SMEFT operators up to mass dimension 8.
|
442 |
Energy-aware localization based on an optimized anchor deployment in wireless sensor networksEl Houssaini, Dhouha 16 January 2023 (has links)
Various applications of Wireless Sensor Networks (WSNs) require accurate localization of sensor nodes. The quantity and locations of anchor nodes, which serve as reference points for distance estimates, as well as the localization process itself, affect the localization accuracy. Furthermore, because numerous communications are sent between nodes for localization, energy consumption must be considered. This work presents an energy-aware and accurate localization method. It is based on a combined anchor deployment and energy-aware localization. The proper number and distribution of anchors have been investigated to achieve full network coverage and connectivity based on an efficient and heterogeneous hexagonal deployment. Later, energy-aware localization is performed in three stages: Initialization, signal acquisition, and anchor selection. The initialization step allows the network to be adaptable to sudden changes by establishing anchor connectivity and creating the neighbors' list. Meanwhile, the Received Signal Strength Indicator (RSSI) is used for distance measurements between nodes, with the implementation of a Kalman
filter to reduce signal attenuation and noise. Later, the anchor selection is done using fuzzy logic with inference parameters: RSSI, node density, and residual energy. This step ensures that only operable anchors engage in localization, while anchors with inadequate energy sources remain intact to ensure their future availability.:1 Introduction
2 Theoretical background
3 Energy-aware outdoor deployment and localization
4 Proposed anchor deployment method
5 Proposed energy-aware localization method
6 Experimental validation of the proposed localization method / Verschiedene Anwendungen von drahtlosen Sensornetzwerken (WSNs) erfordern eine genaue Lokalisierung von Sensorknoten. Die Anzahl und Standorte der Ankerknoten, die als Referenzpunkte für Entfernungsschätzungen dienen, sowie der Lokalisierungsprozess selbst beeinflussen die Lokalisierungsgenauigkeit. Da für die Lokalisierung zahlreiche Nachrichten zwischen den Knoten gesendet werden, muss außerdem der Energieverbrauch berücksichtigt werden. In dieser Arbeit wird eine energiebewusste und genaue Lokalisierungsmethode vorgestellt. Sie basiert auf einer Kombination aus effizienter Ankerknotennutzung und energiebewusster
Lokalisierung. Die richtige Anzahl und Verteilung von Ankern wurde untersucht, um eine vollständige Netzabdeckung und Konnektivität auf der Grundlage einer effizienten und heterogenen hexagonalen Verteilung zu erreichen. Später wird die energiebewusste Lokalisierung in drei Stufen durchgeführt: Initialisierung, Signalerfassung und Ankerauswahl. Der Initialisierungsschritt ermöglicht es dem Netzwerk, sich an plötzliche Veränderungen anzupassen, indem es die Verbindung zu den Ankern und die Liste der Nachbarn erstellt. Zunächst wird der Received Signal Strength Indicator (RSSI) für die Entfernungsmessung zwischen den Knoten verwendet, wobei ein Kalman-Filter implementiert wird, um Signalabschwächung und Rauschen zu reduzieren. Später erfolgt die Ankerauswahl mit Hilfe von Fuzzy-Logik und Inferenzparametern: RSSI, Knotendichte und Restenergie. Dieser Schritt stellt sicher, dass nur funktionsfähige Anker an der Lokalisierung teilnehmen, während Anker mit unzureichenden Energiequellen intakt bleiben, um ihre zukünftige Verfügbarkeit zu gewährleisten.:1 Introduction
2 Theoretical background
3 Energy-aware outdoor deployment and localization
4 Proposed anchor deployment method
5 Proposed energy-aware localization method
6 Experimental validation of the proposed localization method
|
443 |
Atomic Layer Deposition and High Sensitivity-Low Energy Ion Scattering for the Determination of the Surface Silanol Density on Glass and Unsupervised Exploratory Data Analysis with Summary Statistics and Other MethodsGholian Avval, Tahereh 18 July 2022 (has links)
With the increasing importance of hand-held devices with touch displays, the need for flat panel displays (FPDs) will likely increase in the future. Glass is the most important substrate for FPD manufacturing, where both its bulk and surface properties are critical for its performance. Many properties of the glass used in FPDs are controlled by its surface chemistry. Surface hydroxyls are the most important functional groups on a glass surface, which control processes that occurs on oxide surfaces, including wetting, adhesion, electrostatic charging and discharge, and the rate of contamination. In this dissertation, I present a new approach for determining surface silanol densities on planar surfaces. This methodology consists of tagging surface silanols using atomic layer deposition (ALD) followed by low energy ion scattering (LEIS) analysis of the tags. The LEIS signal is limited to the outermost atomic layer, i.e., LEIS is an extremely surface sensitive technique. Quantification in LEIS is straightforward in the presence of suitable reference materials. An essential part of any LEIS measurement is the preparation and characterization of the sample and appropriate reference materials that best represent the samples. My tag-and-count method was applied to chemically and thermally treated fused silica. In this work, I determined the silanol density of a fully hydroxylated fused silica surface to be 4.67 OH/nm2. This value agrees with the literature value for high surface area silica powder. My methodology should be important in future glass studies. Surface Science Spectra (SSS) is an important, peer-reviewed database of spectra from surfaces. Recently, SSS has been expanding to accept spectra from new surface techniques. I created the first SSS submission form for LEIS spectra (see appendix 5), and used it to create the first SSS LEIS paper (on CaF2 and Au reference materials, see chapter 3). I also show LEIS reference spectra for ZnO, and copper in the appendix 1. The rest of my dissertation focuses on my chemometrics/informatics and data analysis work. For example, I showed the performance and capabilities of a series of summary statistics as new tools for unsupervised exploratory data analysis (EDA) (see chapter 4). Unsupervised EDA is often the first step in understanding complex data sets because it can group, and even classify, samples according to their spectral similarities and differences. Pattern recognition entropy (PRE) and other summary statistics are direct methods for analyzing data - they are not factor-based approaches like principal component analysis (PCA) or multivariate curve resolution (MCR). I show that, in general, PRE outperforms the other summary statistics, especially in image analysis, although I recommend a suite of summary statistics be used in exploring complex data sets. In addition, I introduce the concept of divided spectrum-PRE (DS-PRE) as a new EDA method and use it to analyze multiple data sets. DS-PRE increases the discrimination power of PRE. I have also prepared a guide that discusses the vital aspects and considerations for chemometrics/informatics analyses of XPS data along with specific EDA tools that can be used to probe XPS data sets, including PRE, PCA, MCR, and cluster analysis (see chapter 5). I emphasize the importance of an initial evaluation/plotting of raw data, data preprocessing, returning to the original data after a chemometrics/informatics analysis, and determining the number of abstract factors to keep in an analysis, including reconstructing the data using PCA. In my thesis, I also show the analysis of commercial automotive lubricant oils (ALOs) with various chemometrics techniques (see chapter 6). Using these methods, the ALO samples were readily differentiated according to their American Petroleum Institute (API) classification and base oil types: mineral, semi-synthetic, and synthetic.
|
444 |
Spatially resolved optical measurements on supported metal particles and oxide surfaces with the STMBenia, Hadj Mohamed 08 December 2008 (has links)
In der vorliegenden Arbeit wurde mit Hilfe eines Photon-STM die Korrelation zwischen optischen Eigenschaften und der lokalen Morphologie an zwei unterschiedlichen Systemen untersucht. Hierfür wurden zum einem oxidgetragene Ensemble von Silber-Partikeln präpariert, wobei sowohl die Partikelform (Kuppel- und Scheibenform) als auch die deponierte Partikeldichte variiert werden konnte. Neben der Präparation solcher Partikel auf Al10O13/NiAl, konnten sphärische Silber-Kolloide geordnet, als auch ungeordnet auf HOPG aufgebracht und untersucht werden. Dabei zeigte sich, dass das Verhältnis von Höhen zu Breiten nicht nur einen signifikanten Einfluss auf die Mie-Resonanz des einzelnen Partikels hat, sondern auch die elektromagnetische Kopplung der Partikel in einem Ensemble stark kontrolliert. Die energetische Lage der Mie-Resonanz zeigt im Fall der kuppelförmigen Ag-Partikel eine starke Abhängigkeit vom Intepartikel-Abstand, was sich in einer Verschiebung zu höheren Energien für eine steigende Partikeldichte äußert. Eine solche Abhängigkeit konnte bei den Ensembles der scheibenförmigen Partikel nicht beobachtet werden. Des weiteren zeigte sich, dass, verglichen mit den ungeordneten Ensembles, die selbstorganisierte langreichweitige Ordnung der Silber-Kolloide auf HOPG nur einen schwachen Einfluss auf die energetische Position der Mie Resonanz hat.Das zweite hier untersuchte System sind dünne MgO Filme unterschiedlicher Dicken auf einem Mo(001) Substrat. Diese zeigen ein reichhaltiges Wachstumsverhalten, welches durch eine Differenz in den Gitterkonstanten von 5.3% begründet ist und erst ab etwa 25 ML zu einem flachen und defektarmen Film führt. Die so induzierte Spannung relaxiert bis zu einer Dicke von etwa 7 ML in einer periodischen Überstruktur die aus abwechselnd flachen und verkippten Ebenen an der MgO-Mo Grenzschicht hervorgeht. Für MgO Filme mit einer Dicke von etwa 12 ML werden dann Schraubenversetzungen, ausgedehnte verkippte Ebenen und Stufenkanten mit einer Orientierung entlang der Richtung beobachtet. Die optische Charakterisierung durch Feldemission von Elektronen aus der STM-Spitze in den MgO-Film wird dominiert von zwei Emissionsmaxima bei Energien von 3.1 eV und 4.4 eV. Die kontrollierte Nukleation von Gold Partikeln und die Erzeugung von Farbzentren im MgO Film erlaubten eine Zuordnung dieser Emissionen zu strahlenden Zerfällen von Exitonen an Ecken, Kinken bzw. Stufen des Magnesiumoxids. Solche Emissionsprozesse konnten allerdings nur unter Einstellungen beobachtet werden, bei denen ein gleichzeitiges Rastern der Oberfläche unmöglich ist. Bei moderaten Einstellungen war auch eine ortsaufgelösten Spektroskopie möglich, wobei dann neue Emissionsmechanismen beobachtet wurden. Dabei sind zwei Prozesse wesentlich; zum einen die Ausbildung von sog. Spitzen-induzierten Plasmonen im Bereich zwischen Spitze und dem Mo-Substrat, zum anderen strahlende Elektronenübergänge zwischen sog. Feldemissionsresonanzen, die sich im Spitze/MgO-Film System ausbilden. / In this thesis, the correlation between the optical properties and the local morphology of supported silver nanoparticle ensembles and MgO thin films deposited on Mo(001) systems is explored by means of Photon-STM. In the first section, dome and disk shaped Ag nanoparticle ensembles with increasing density on an alumina film on NiAl(110) were analyzed as well as ordered and disordered ensembles of Ag nanocolloids on HOPG. The aspect ratio of the Ag nanoparticles was found to have a significant influence not only on the Mie plasmon resonance of a single particle, but also on the electromagnetic coupling within the nanoparticle ensembles. The Mie resonance in the ensemble of dome shaped Ag nanoparticles shows a strong dependence on the interparticle distance, where it shifts to higher energies with increasing particle density, due to destructive interference effects. In the disk-like Ag ensembles, however, the plasmon energy is independent of particle-particle separation. The long-range lateral ordering of size-selected Ag nanocolloids is found to induce a high dipole-dipole coupling within the ensemble. This is mainly reflected by the enhancement of the spectral intensity of the in-plane Mie mode, due to constructive coupling. However, ensembles with either well-ordered or disordered arrangements reveal no important difference in their optical properties, reflecting the weak influence of the long-range order in the particle ensemble. Thin MgO films with different thicknesses were grown on a Mo(001) surface. The stress resulting from the 5.3% lattice mismatch between the MgO(001) and the Mo(001) lattice parameters is found to control the surface morphology of the MgO film until thicknesses of around 25ML at which flat and defect-poor films are obtained. The relaxation of the stress induces a periodic network in the first 7ML of the MgO film, consisting of alternated flat and tilted mosaics. The presence of screw dislocations, steps oriented along the MgO directions, and tilted planes is observed when the MgO films are approximately 12ML thick. In addition, an increase of the MgO work function around these new surface features is revealed from STM spectroscopy. The photon emission induced by field-emitted electron injection from the STM tip into the MgO films is dominated by two emission bands located at 3.1eV and 4.4eV. To check the origin of these bands, further experiments, namely, nucleation of Au particles and creation of F-centers on the MgO surface, have been performed. The nucleation of Au particles at the low coordinated sites is found to quench the MgO optical signal, while the creation or annihilation of F-centers does not alter the MgO emission bands. The 3.1eV and the 4.4eV bands are therefore assigned to the radiative decay of MgO excitons at corner and kink sites, and step sites, respectively. Besides, spatially resolved optical measurements in the tunneling mode of the STM revealed different light emission mechanisms. These radiative processes are mainly related to tip-induced plasmons that form between the tip and the Mo support and to electron transitions between field-emission-resonance states in the STM tip-MgO film junction. The signal from exciton decays at corners and kinks of the MgO surface is however only observed at excitation conditions where the spatial resolution is already strongly reduced.
|
445 |
Διατάξεις παγίδευσης φορτίου (Memories) με τη χρήση νέων υλικών υψηλής διηλεκτρικής σταθεράςΝικολάου, Νικόλαος 07 May 2015 (has links)
Στη παρούσα Διατριβή διερευνήθηκε η χρήση υλικών υψηλής διηλεκτρικής σταθεράς (high-k) ως οξειδίων ελέγχου σε διατάξεις παγίδευσης φορτίου τύπου MONOS (Μetal-Οxide-Νitride-Οxide-Silicon). Τα οξείδια που εξετάστηκαν ήταν το HfO2, τo ZrO2 και το Al2O3. Η ανάπτυξή τους πραγματοποιήθηκε με χρήση της μεθόδου εναπόθεσης ατομικού στρώματος (ALD).
Οι ιδιότητες των δομών μνήμης μελετήθηκαν συναρτήσει: (α) των πρόδρομων μορίων της εναπόθεσης για τα HfO2 και ZrO2, (β) του οξειδωτικού μέσου της εναπόθεσης για την περίπτωση του Al2O3 και (γ) της επακόλουθης ανόπτησης. Η ηλεκτρική συμπεριφορά των δομών εξετάστηκε με την κατασκευή πυκνωτών τύπου MOS.
Τα υμένια του HfO2 αναπτύχθηκαν επί διστρωματικής στοίβας SiO2/Si3N4 με (α) αλκυλαμίδιο του χαφνίου (ΤΕΜΑΗ) και Ο3 στους 275 oC, και (β) κυκλοπενταδιενύλιο του χαφνίου (HfD-04) και Ο3 στους 350 οC. Ομοίως, τα υμένια του ZrO2 αναπτύχθηκαν επί διστρωματικής στοίβας SiO2/Si3N4 με: (α) αλκυλαμίδιο του ζιρκονίου (ΤΕΜΑΖ) και Ο3 στους 275 oC και (β) κυκλοπενταδιενύλιο του ζιρκονίου (ZrD-04) με Ο3 στους 350 oC. Ο δομικός χαρακτηρισμός, για το HfO2, φανέρωσε πως η ύπαρξη ή όχι κρυσταλλικού χαρακτήρα και η σύσταση του οξειδίου εξαρτάται τόσο από το πρόδρομο μόριο αλλά και από την ανόπτηση (600 οC, 2 min). Αντίθετα, το ZrO2 έχει σε κάθε περίπτωση κρυσταλλικότητα. Τα ηλεκτρικά χαρακτηριστικά των πυκνωτών Si/SiO2/Si3N4/high-k/Pt, δείχνουν ότι οι δομές έχουν ικανοποιητική συμπεριφορά ως στοιχεία μνήμης αφού όλες οι ιδιότητες πληρούν τις βασικές προϋποθέσεις ως στοιχεία μνήμης, παρά την ανυπαρξία ενεργειακού φραγμού μεταξύ στρώματος παγίδευσης και οξειδίου ελέγχου. Η ικανότητα παγίδευσης και η επίδοση των δομών με HfO2 και ZrO2 δεν διαφοροποιούνται σημαντικά με χρήση διαφορετικού πρόδρομου μορίου ή με την ανόπτηση. Ο έλεγχος όμως της αντοχής των δομών σε επαναλαμβανόμενους παλμούς εγγραφής/διαγραφής αναδεικνύει ότι αμφότερες οι δομές που ανεπτύχθησαν με βάση το κυκλοπενταδιενύλιο έχουν μειωμένη αντοχή ηλεκτρικής καταπόνησης.
Τo Al2O3 αναπτύχθηκε χρησιμοποιώντας το μόριο ΤΜΑ και ως οξειδωτικό μέσο: (α) H2O, (β) O3 και (γ) Plasma Ο2 (μέθοδος PE-ALD) σε συνδυασμό με ΤΜΑ. Οι δομές στην αρχική κατάσταση, χωρίς ανόπτηση, χαρακτηρίζονται από ισχυρό ρεύμα έγχυσης ηλεκτρονίων από την πύλη (υπό αρνητικές τάσεις) περιορίζοντας την ικανότητα φόρτισης και την επίδοση διαγραφής. Η ανόπτηση σε φούρνο και αδρανές περιβάλλον (850 ή 1050 oC, 15 min) προκάλεσε σημαντική βελτίωση των ηλεκτρικών χαρακτηριστικών των δομών λόγω του σημαντικού περιορισμού του παραπάνω φαινομένου. Μετά το στάδιο της ανόπτησης οι συνδυασμοί ΤΜΑ/Η2Ο και ΤΜΑ/Plasma Ο2 έχουν καλύτερες χαρακτηριστικές σε σχέση με αυτές του συνδυασμού ΤΜΑ/Ο3. Το φαινόμενο της διαρροής ηλεκτρονίων από την πύλη αποδίδεται στη μεγάλη συγκέντρωση και χωρική κατανομή του υδρογόνου στο υμένιο υψηλής διηλεκτρικής σταθεράς.
Τέλος, διερευνήθηκε η τροποποίηση των ιδιοτήτων μνήμης των δομών με εμφύτευση ιόντων αζώτου χαμηλής ενέργειας και υψηλής δόσης στο Al2O3 και επακόλουθη ανόπτηση υψηλής θερμοκρασίας. Η παρουσία αζώτου στο υμένιο καθώς και ο χημικός δεσμός του εμφυτευμένου αζώτου είναι συνάρτηση της θερμοκρασίας ανόπτησης. Επομένως, οι ιδιότητες μνήμης εξαρτώνται από τη μορφή σύνδεσης και την συγκέντρωση του εμφυτευμένου αζώτου στο τροποποιημένο Al2O3. Η υψηλή θερμοκρασία ανόπτησης (1050 οC, 15 min) φαίνεται να αποφέρει δομές με τις καλύτερες ιδιότητες μνήμης. / This thesis studies the functionality of high-k oxides as blocking oxide layers in SONOS type charge-trap memory devices. The oxide materials that were examined were the HfO2, the ZrO2 and the Al2O3. All these blocking oxide layers were deposited by atomic layer deposition technique (ALD). The electrical performance of the trilayer stacks was examined using Pt-gate MOS-type capacitors.
The properties of the memory structures were examined as a function of: (a) precursor chemistry of HfO2 and ZrO2 deposition, (b) the deposition oxidizing agent in the case of Al2O3 and (c) subsequent high temperature annealing steps.
The HfO2 films were deposited on SiO2/Si3N4 bilayer stacks using: (a) hafnium alkylamide (TEMAH) and O3 at 275 oC, and (b) hafnium cyclopentadienyl (HfD-04) and O3 at 350 oC. Similarly the ZrO2 films were deposited by (a) zirconium alkylamide (TEMAZ) and O3 at 275 oC, and (b) zirconium cyclopentadienyl (ZrD-04) and O3 at 350 oC
The structural characterization of the HfO2 showed that the crystallinity of the deposited high-k material depends on the precursor choice and the post deposition annealing step (600 °C, 2 min). On the contrary ZrO2 is deposited in a crystalline phase independent of the deposition conditions and the choice of the precursors. The electrical characterization of Si/SiO2/Si3N4/high-k/Pt capacitors showed that all fabricated structures operate well as memory elements, despite the absence of an energy barrier between the trapping layer and control oxide. The trapping efficiency and the performance of structures with HfO2 or ZrO2 blocking layers do not revealed a dependence upon the precursor chemistry. However, endurance testing using continuous write/erase pulses showed that both structures deposited by cyclopentadienyl precursors cannot sustain the resulting electrical stress.
The Al2O3 layers were deposited using the TMA molecule while three different oxidizing agents were used: (a) H2O, (b) O3 and (c) oxygen plasma. Electrical testing of the resulting Pt-gate trilayer capacitors showed that in the deposited condition all three samples were characterized by gate electrode induced electron leakage currents in the negative bias regime, which completely masked the substrate hole injection effects. This effect limits the performance and the functionality of the memory stacks. After a high temperature annealing step (850 or 1050 oC, 15 min) this leakage current is reduced significantly and the stacks can function as memory elements. The results point to suggest that after annealing the best performance is exhibited by the TMA/H2O and TMA/Plasma O2 samples. The effect of gate induced electron leakage current is attributed to hydrogen related contamination, which has been verified by ToF-ERDA in depth profile measurements, at least for the case of TMA/H2O samples.
The modification of the memory properties of the SiO2/Si3N4/Al2O3 stacks was also investigated using low energy and high fluence nitrogen implantation into Al2O3 layer. The concentration and the chemical bonding of the implanted nitrogen is a function of annealing temperature. The memory properties of the stack depend therefore on the chemical bonding and the concentration of the remaining nitrogen in the modified Al2O3. The high temperature annealing (1050 oC, 15 min) appears to provide the structures with improved memory properties in terms of retention and fast erase performance.
|
446 |
Potential Energy Minimization as the Driving Force for Order and Disorder in Organic Layers / Potentialenergie-Minimierung als Triebfeder für Ordnung und Unordnung in organischen SchichtenWagner, Christian 15 June 2010 (has links) (PDF)
The topic of this work is the structural characterization and theoretical modeling of organic single and heterolayers. The growth of sub-monolayers and monolayers (ML) of the two polycyclic aromatic hydrocarbons quaterrylene (QT) and hexa-peri-hexabenzocoronene (HBC) on Ag(111) and Au(111) was investigated. A transition from a disordered, isotropic phase to an ordered phase with increasing coverage was found. The lattice of the ordered phase turned out to be coverage dependent. The intermolecular potential was modeled including Coulomb and van der Waals interaction by a force-field approach. The postulated repulsive character of the potential could be connected to the non-uniform intramolecular charge distribution and to a screening of the van der Waals forces. Furthermore, the influence of the variable lattice constant on the epitaxial growth of HBC was studied. The second part of this work deals with a ML of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on a ML of HBC. In dependency on the initial lattice constant of HBC, a total of three line-on-line (LOL) and point-on-line coincident phases of PTCDA (with respect to HBC) was found. Following an analysis of the general properties of LOL coincident systems via force-field calculations, a new method to predict the structure of such systems is introduced. / Thema dieser Arbeit ist die strukturelle Charakterisierung von organischen Einfach- und Heterolagen sowie deren theoretische Beschreibung und Modellierung. Es wurden Submonolagen und Monolagen (ML) der polyzyklischen Kohlenwasserstoffe Quaterrylen (QT) und Hexa-peri-hexabenzocoronen (HBC) auf Ag(111) und Au(111) Einkristallen untersucht und ein Übergang von einer ungeordneten, isotropen Phase zu einer geordneten Phase mit steigender Bedeckung beobachtet. Die geordnete Phase wies dabei bedeckungsabhängige Gitterkonstanten auf. Das intermolekulare Potential wurde unter Berücksichtigung von Coulomb und van der Waals Anteilen mittels Kraftfeldmethoden modelliert. Der postulierte repulsive Charakter des Potentials konnte auf die Ladungsverteilung im Molekül und eine Abschwächung des van der Waals Potentials zurückgeführt werden. Weiterhin wurde der Einfluss der variablen HBC Gitterkonstante auf die epitaktische Relation des Gitters zum Metallsubstrat untersucht. Der zweite Teil der Arbeit widmet sich der Untersuchung einer ML 3,4,9,10-Perylenetetracarboxylic dianhydrid (PTCDA) auf einer ML HBC. Dabei wurden, in Abhängigkeit von der HBC Gitterkonstante, insgesamt drei verschiedene Typen von line-on-line bzw. point-on-line Epitaxie nachgewiesen. Im Anschluss an eine Analyse der generellen Eigenschaften solcher epitaktischer Lagen mittels Kraftfeldrechnungen wird eine neue Methode zur Vorhersage der Struktur konkreter Systeme vorgestellt.
|
447 |
Revitalizace hotelového zařízení, Přehrada Brno / Revitalisation of the Hotel Facility by the Brno Artificial LakeŠvec, Martin Unknown Date (has links)
This is the proposal of the new utilization of the former recreational centre, which is situated in the beautiful surrounding of the Brno lake. It has been abandoned for many years and is suffering from decay. It has been built in the 1970's for the demand of the Socialistic youth union (remark: the youth organisation of the communist's party). There were held international political conventions and educational sojourns for the students of high schools and universities. The new utilization will be analogous. Only the communist's ideals will be replaced with the ideals of today's democratical society – especially friendly relations between mankind and environment. There will be created the environmental educational centre with the meeting spaces, conference hall and accomodation. The universal concept enables the usage of the facility also for the international students' workshops, training courses, teambuilding events etc. The ecological educational centre primarily makes the good example and is the live educational requisite. Thanks to the concept of the original facility is very convenient the refurbishment to the standard of the energetically passive building, which consists from the natural materials and utilizes renewable energy resources. Because of the very poor technical condition and devastation of the building will be re-used only basement and steel framework. This solution is more economical than the demolition and following new construction. The construction core of the building is almost for free. However, only if we make minimal changes in the framework and we preserve the original building's shape. On the steel framework will be created the new lightweight housing, which will be made from wood, straw pannels and filled with the cannabis thermal insulation. Almost all the roofs will be covered with the photovoltaic foils and the heat source will be air heat pump. The area is very pleasant place to stay. It's full of sunshine all day long and offers very beautiful view of the lake. The main building and bungalows profit of the attractive views. All the former recreational area has was designed to make the people meeting together and to provide the freedom of move and wide variety of activities. However, the rooms and bungalows provide the highest privacy. The inside and outside of the buildings are shading into each other. All the recreational ground – in exterior and interior – is full of liveliness, in the opposite of the rooms, which are the private islands. This aspect, which is present in the former concept from the 1970's, is to be preserved. The former hotel building is distinguished by the quality architectural concept, above-average in the age of origin. It is thanks to the dynamically balanced composition – inspirative today too, and visually interesting interior design of the meeting spaces. This proposal attempts to continue in this qualities. The ground is enriched with the relaxational spaces and the outside gym path. In the opposite of the original state the area is open to the public and is utilized as a park for leisure activities.
|
448 |
Administrative building with low energy footprint / Administrativní budova s nízkou energetickou stopouSlepánek, František January 2015 (has links)
The aim of this diploma thesis is trying to solve difficulties connected with administrative buildings. In this thesis we are talking about possibility that administrative building can have low energy footprint. Most of energy consumption of administrative building is not created by heating but mostly by cooling and by consumption of office equipment. That is why there have been used modern equipment of the building as well as automatic control of building equipment.
|
449 |
Potential Energy Minimization as the Driving Force for Order and Disorder in Organic LayersWagner, Christian 07 June 2010 (has links)
The topic of this work is the structural characterization and theoretical modeling of organic single and heterolayers. The growth of sub-monolayers and monolayers (ML) of the two polycyclic aromatic hydrocarbons quaterrylene (QT) and hexa-peri-hexabenzocoronene (HBC) on Ag(111) and Au(111) was investigated. A transition from a disordered, isotropic phase to an ordered phase with increasing coverage was found. The lattice of the ordered phase turned out to be coverage dependent. The intermolecular potential was modeled including Coulomb and van der Waals interaction by a force-field approach. The postulated repulsive character of the potential could be connected to the non-uniform intramolecular charge distribution and to a screening of the van der Waals forces. Furthermore, the influence of the variable lattice constant on the epitaxial growth of HBC was studied. The second part of this work deals with a ML of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on a ML of HBC. In dependency on the initial lattice constant of HBC, a total of three line-on-line (LOL) and point-on-line coincident phases of PTCDA (with respect to HBC) was found. Following an analysis of the general properties of LOL coincident systems via force-field calculations, a new method to predict the structure of such systems is introduced.:1 Introduction
2 Experimental Methods
2.1 Organic molecular beam epitaxy
2.2 Scanning tunneling microscopy (STM)
2.3 Low-energy electron diffraction (LEED)
2.4 Molecules and substrates: Basic properties and literature review
2.4.1 3,4,9,10-Perylenetetracarboxylic dianhydride
2.4.2 Hexa-peri-hexabenzocoronene
2.4.3 Quaterrylene
2.4.4 Metal substrates: Au(111) and Ag(111)
3 Theory and Modeling
3.1 Reciprocal space and LEED
3.1.1 Fourier transform and geometrical LEED theory
3.1.2 Kinematic and dynamic LEED theory
3.1.3 Further applications of the Fourier transform
3.2 Computational chemistry
3.2.1 Calculating molecular properties
3.2.2 The atomic force-field method
3.2.3 Potential energy calculations in extended systems
4 Epitaxy in terms of potential energy
5 Interaction of QT and HBC at Sub-ML and ML Coverage
5.1 Experimental results
5.2 Modeling technique
5.3 Results of the model calculation
5.4 Discussion of results
5.5 Conclusion
6 The Ordered Phases of HBC on Ag(111) and Au(111
6.1 Geometrical analysis of epitaxy
6.2 Energetic gain of epitaxial structures
6.3 Comparison to experiment
6.4 Influence of the Au(111) surface reconstruction
6.5 Conclusion
7 Organic Heterosystems of PTCDA and HBC on Au(111)
7.1 PTCDA on Au(111) revisited
7.2 LEED and STM on PTCDA/HBC/Au(111) samples
7.2.1 A “compact” HBC layer substrate
7.2.2 A “loosely packed” HBC layer substrate
7.2.3 Summary of LEED results
7.2.4 STM results
7.3 Epitaxial relations in the system PTCDA/HBC/Au(111)
7.3.1 Geometrical analysis of epitaxy
7.3.2 Energetic gain of epitaxial structures
7.3.3 Mutual alignment of lattices
7.4 Heterosystems of PTCDA and HBC with inverted stacking sequence
8 General Properties of POL and LOL Epitaxy
8.1 A new coordinate system
8.2 Specific properties of the substrate-adsorbate potential
8.3 The “natural order” of the lattice lines
8.4 Prediction of epitaxial growth - a “LOL predictor”
8.4.1 Method
8.4.2 Results
9 General Conclusions and Future Perspectives
9.1 Conclusion
9.2 Outlook
Appendix
A.1 Conductance in a STM: The 1D WKB model
A.2 Extraction of the DOS from STS measurements by means of the 1D WKB model
A.3 Practical application of the 1D WKB model
A.4 The normalized differential conductivity
A.5 A new normalization method / Thema dieser Arbeit ist die strukturelle Charakterisierung von organischen Einfach- und Heterolagen sowie deren theoretische Beschreibung und Modellierung. Es wurden Submonolagen und Monolagen (ML) der polyzyklischen Kohlenwasserstoffe Quaterrylen (QT) und Hexa-peri-hexabenzocoronen (HBC) auf Ag(111) und Au(111) Einkristallen untersucht und ein Übergang von einer ungeordneten, isotropen Phase zu einer geordneten Phase mit steigender Bedeckung beobachtet. Die geordnete Phase wies dabei bedeckungsabhängige Gitterkonstanten auf. Das intermolekulare Potential wurde unter Berücksichtigung von Coulomb und van der Waals Anteilen mittels Kraftfeldmethoden modelliert. Der postulierte repulsive Charakter des Potentials konnte auf die Ladungsverteilung im Molekül und eine Abschwächung des van der Waals Potentials zurückgeführt werden. Weiterhin wurde der Einfluss der variablen HBC Gitterkonstante auf die epitaktische Relation des Gitters zum Metallsubstrat untersucht. Der zweite Teil der Arbeit widmet sich der Untersuchung einer ML 3,4,9,10-Perylenetetracarboxylic dianhydrid (PTCDA) auf einer ML HBC. Dabei wurden, in Abhängigkeit von der HBC Gitterkonstante, insgesamt drei verschiedene Typen von line-on-line bzw. point-on-line Epitaxie nachgewiesen. Im Anschluss an eine Analyse der generellen Eigenschaften solcher epitaktischer Lagen mittels Kraftfeldrechnungen wird eine neue Methode zur Vorhersage der Struktur konkreter Systeme vorgestellt.:1 Introduction
2 Experimental Methods
2.1 Organic molecular beam epitaxy
2.2 Scanning tunneling microscopy (STM)
2.3 Low-energy electron diffraction (LEED)
2.4 Molecules and substrates: Basic properties and literature review
2.4.1 3,4,9,10-Perylenetetracarboxylic dianhydride
2.4.2 Hexa-peri-hexabenzocoronene
2.4.3 Quaterrylene
2.4.4 Metal substrates: Au(111) and Ag(111)
3 Theory and Modeling
3.1 Reciprocal space and LEED
3.1.1 Fourier transform and geometrical LEED theory
3.1.2 Kinematic and dynamic LEED theory
3.1.3 Further applications of the Fourier transform
3.2 Computational chemistry
3.2.1 Calculating molecular properties
3.2.2 The atomic force-field method
3.2.3 Potential energy calculations in extended systems
4 Epitaxy in terms of potential energy
5 Interaction of QT and HBC at Sub-ML and ML Coverage
5.1 Experimental results
5.2 Modeling technique
5.3 Results of the model calculation
5.4 Discussion of results
5.5 Conclusion
6 The Ordered Phases of HBC on Ag(111) and Au(111
6.1 Geometrical analysis of epitaxy
6.2 Energetic gain of epitaxial structures
6.3 Comparison to experiment
6.4 Influence of the Au(111) surface reconstruction
6.5 Conclusion
7 Organic Heterosystems of PTCDA and HBC on Au(111)
7.1 PTCDA on Au(111) revisited
7.2 LEED and STM on PTCDA/HBC/Au(111) samples
7.2.1 A “compact” HBC layer substrate
7.2.2 A “loosely packed” HBC layer substrate
7.2.3 Summary of LEED results
7.2.4 STM results
7.3 Epitaxial relations in the system PTCDA/HBC/Au(111)
7.3.1 Geometrical analysis of epitaxy
7.3.2 Energetic gain of epitaxial structures
7.3.3 Mutual alignment of lattices
7.4 Heterosystems of PTCDA and HBC with inverted stacking sequence
8 General Properties of POL and LOL Epitaxy
8.1 A new coordinate system
8.2 Specific properties of the substrate-adsorbate potential
8.3 The “natural order” of the lattice lines
8.4 Prediction of epitaxial growth - a “LOL predictor”
8.4.1 Method
8.4.2 Results
9 General Conclusions and Future Perspectives
9.1 Conclusion
9.2 Outlook
Appendix
A.1 Conductance in a STM: The 1D WKB model
A.2 Extraction of the DOS from STS measurements by means of the 1D WKB model
A.3 Practical application of the 1D WKB model
A.4 The normalized differential conductivity
A.5 A new normalization method
|
450 |
Bytový dům ve Zlíně / Residential building in ZlinJelínek, Roman January 2013 (has links)
The aim of this thesis is to elaborate project documentation for new construction of low-energy residential building with 16 luxury apartments, apartment without barriers and with pharmacy of basic type. It is a four-storey detached building without basement, with flat roof, roof terraces and with balconies. Residential building is located in one of the most enjoyable parts of the city of Zlín – Jižní Svahy II in the vicinity of Central park with bicycle path and with beautiful view of the Zlín. The building will be located on land plot No. 2144/46, where is still situated unfinished building "Torso" from the late 80 years. The residential building is designed in brick system Heluz, ceiling construction is made up of prestressed hollow core slabs, perimeter walls are with external thermal insulation composite system and external doors and windows are made of plastic and aluminum with triple glazing. For heating and water heating will be utilized renewables energy, such as heat pump and solar collectors. Residential units with three residential rooms are designed with a forced ventilation by means of ventilation units with heat recovery. The building also uses modern shielding elements such as outdoor blinds and horizontal sun breakers. The part of the project are also disposition studies, seminar work and energy part.
|
Page generated in 0.0485 seconds