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1
Seehamart, Kompichit. "Investigation of the diffusion mechanisms of several hydrocarbons in the Metal-Organic-Framework Zn(tbip)." Doctoral thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-68125.
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Most of the computer simulations of molecules in Metal-Organic Frameworks (MOFs) to be found in the literature are done with rigid framework. But, Molecular Dynamics (MD) simulations of the self-diffusivity, Ds, of ethane within the one-dimensional 4.5 Å channels of the MOF type Zn(tbip)(H2 tbip = 5-tert-butyl isophthalic acid) presented in this work have shown not only quantitative, but also qualitative, differences in the Ds values for fixed and flexible lattices. Particularly, the dependence of Ds upon the concentration of molecules, c, is strongly influenced by the lattice flexibility. The reasons for this influence are investigated with the aid of probability density plots, free energy landscapes and barriers, along with a determination of the structural changes accompanying increasing c. It is found that for flexible lattices, the tighter, more constrained parts of the channels become wider at higher c; this allows more molecules to diffuse in the central region of the channels.
The investigations for Zn(tbip) have been extended to three equimolar mixtures of ethane/ethane, CO2/ethane and CO2/methanol. The simulations take into account the lattice flexibility. The diffusional characteristics are discussed in relation to molecule properties and lattice geometry. The results show that Zn(tbip) may be a useful material for separating methane/ethane and CO2/ethane mixtures at low concentrations, and CO2/methanol mixtures at high concentrations.
The temperature and concentration dependence of the self-diffusivity of propane diffusion in Zn(tbip) have been investigated as well by performing normal MD and hyper-MD with bias potential simulations. The obtained temperature dependence of the self-diffusivities is analyzed using an Arrhenius relationship, yielding the activation energy to be 9.53 kJ/mol and the pre-exponential factor to be 4.48×10-9 m2s-1. Using this hyper-MD method, interesting mechanisms of the propane molecules able to pass each other and exchange their sites in the channels can be observed. Because of mutual hindrance of propane molecules, the propane self-diffusivities decrease with increasing concentration.
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Rial, Djihad. "Modélisation tridimensionnelle des flexibles hydroformés et tressés en statique et en fatigue." Electronic Thesis or Diss., Compiègne, 2015. http://www.theses.fr/2015COMP2184.
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Dans cette étude, le comportement mécanique des flexibles ondulés est étudié expérimentalement et numériquement. Afin de surmonter l’important coût de calcul, des solutions analytiques de la théorie des coques toriques ont été utilisées pour homogénéiser le comportement global en utilisant des poutres simples à propriétés équivalentes. Ensuite, le modèle analytique proposé a été vérifié en le comparant avec des modèles éléments finis en trois dimensions. Des essais expérimentaux ont été conçus pour étudier l’expansion sous pression et le comportement en flexion de ces structures. Il est démontré que lorsque le modèle est implémenté dans un code d’éléments finis, il donne des résultats acceptables avec une réduction considérable temps de calcul. D’autre part, l’importance de la prise en compte des contraintes résiduelles résultant de l’opération d’hydroformage a été montrée. Cette étude consiste aussi à simuler le comportement des tresses métalliques numériquement en utilisant différentes approches – une approche "micro-échelle" directe avec des éléments solides 3D ou des éléments de poutres pour chaque fil métallique, ainsi que des approches homogénéisées où des éléments finis continus sont utilisés pour représenter soit l’ensemble de la structure qui est le modèle "macro-échelle", soit chaque groupe de fils qui est le modèle "méso-échelle". Ces modèles sont comparés par la suite à des résultats expérimentaux, qui sont: un essai de traction simple et un essai d’expansion sous pression. Une investigation numérique et expérimentale de la tenue en fatigue des flexibles métalliques a été présenté. Des échantillons de flexibles ont été soumis à une série de tests de fatigue lors desquels l’amplitude de chargement mécanique était constante, avec une pression interne continuelle similaire aux conditions de travail. Sachant que ces configurations de chargements génèrent des contraintes (déformations) tridimensionnelles, la durée de vie de la structure a été extraite en termes de nombre de cycles à l’initiation de fissures (perte de pression interne). De plus, un modèle d’éléments finis a été créé en tenant en compte les contraintes résiduelles résultant du procédé d’hydroformage afin d’estimer et de comparer avec l’expérience la durée de vie en fatigue. Cette prédiction a été réalisée à l’aide de différentes approches : une approche contrainte-déformation qui est largement utilisée dans les codes commerciaux, une approche de plan critique, une approche énergétique et une approche basée sur le cumul d’endommagementHydroformed flexible tubes are essential structures used in several industrial sectors such as the automotive sector, the aviation industry or energy production, such as the production of renewable energy in solar thermal energy farms where the panels must both be supplying fluid along and follow the direction of the sun. These structures serve as connecting parts between the rigid parts different mechanisms, primarily used for damping vibrations and acoustic emissions, and, as their name suggests, they also allow flexibility and pressure expansion, which considerably improves the fatigue strength. The mastery and prediction of the mechanical behavior of these structures are very important from a safety point of view and an economic point of view. Indeed, their accidental breakage can cause very serious consequences due to their use in sensitive areas such as the nuclear industry. In this context, this thesis was launched between Compiegne University of Technology and industrial BOA-group to create digital approaches to behavioral predictions and estimating the life braided hoses that take into account extreme conditions (temperature and pressure) and the forming parameters and properties of the materials used. In terms of use, these products are subject to thermomechanical charge-discharge cycles and vibrations can induce complex deformed piping of wear due to friction and damage by fatigue, The purpose of the study is to develop a numerical approach validated by the experience to certify products and improve the design. This approach will allow to estimate the lifetime of braided wavy taking into account: - the initial state of the product after forming and assembly, - thermomechanical stresses, is defined by the specification, or encountered in specific use cases, - vibrations encountered during use in real cases. The expected results are the life of the products from a calculation model of their behavior using the characteristics of the materials and interaction braid / tube
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Cojocaru, Ludmila. "Films d’oxydes semi-conducteurs nanoporeux et nanocristallins pour dispositifs photovoltaïques hybrides." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14630/document.
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Dans le contexte de la mise au point de dispositifs photovoltaïques efficaces, bon marché et respectueux de l’environnement, la synthèse d’oxydes métalliques semi-conducteurs tels que SnO2, Zn2SnO4 et WO3 de morphologies et textures diverses a été développée afin d’élaborer des photoanodes poreuses pour cellules solaires à colorant. D’après les études réalisées par différentes méthodes (MEB, MET, DRX et BET), les matériaux obtenus présentent des caractéristiques texturales, morphologiques et structurales appropriées pour l’application visée. Des cellules solaires à colorant ont donc été réalisées à partir de ces oxydes, puis différents paramètres influençant leurs performances ont été optimisés afin d’améliorer l’efficacité de la conversion photovoltaïque. Notamment l’influence positive de différents traitements des photoanodes (i.e. solution aqueuse de TiCl4 ou traitement à l’eau) sur les rendements de conversion énergétique et la stabilité des dispositifs a été démontrée. Ainsi, des performances comparables ou supérieures à l’état de l’art ont été atteintes pour les systèmes à base de SnO2. Ces performances ont ensuite été interprétées en déterminant les processus électroniques et ioniques ayant lieu dans ces cellules par différentes méthodes physiques (mesures de tension de seuil et de décroissance de circuit-ouvert, spectroscopie d’impédance). Enfin, des électrodes réalisées à partir de WO3 déposé sur substrats flexibles ont démontré des propriétés électrochromes très prometteuses ce qui ouvre de nouvelles perspectives dans le domaine de l’affichageIn the context of the development of efficient, low-cost and environmentally friendly photovoltaic devices, the synthesis of metal-oxide semiconductors such as SnO2, Zn2SnO4 and WO3 with various textures and morphologies have been developed in order to achieve nanoporous photoanodes for dye-sensitized solar cells. According to studies carried out by different characterization methods (SEM, TEM, XRD and BET), the resulting materials show interesting features for the expected application. Dye solar cells were then fabricated from photoanodes processed with these oxides and several parameters influencing their performance were optimized to improve the overall conversion efficiency. In particular, the beneficial effect of different treatments of the photoanodes (ie aqueous TiCl4 or water treatment) on the power conversion efficiency and the stability of the devices has been evidenced. Thus, state-of-the art or, even, record efficiencies were reached in the case of SnO2-based systems. These performances were then rationalized by determining the electronic and ionic processes occurring in these devices by various physical methods (threshold voltage and open-circuit photovoltage decay measurements, electrochemical impedance spectroscopy). Finally, electrodes based on WO3 and deposited on flexible substrates have shown very promising electrochromic properties, which opens up new prospects in the field of smart displays
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Schneemann, Andreas, Volodymyr Bon, Inke Schwedler, Irena Senkovska, Stefan Kaskel, and Roland A. Fischer. "Flexible metal–organic frameworks." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-149990.
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Advances in flexible and functional metal–organic frameworks (MOFs), also called soft porous crystals, are reviewed by covering the literature of the five years period 2009–2013 with reference to the early pertinent work since the late 1990s. Flexible MOFs combine the crystalline order of the underlying coordination network with cooperative structural transformability. These materials can respond to physical and chemical stimuli of various kinds in a tunable fashion by molecular design, which does not exist for other known solid-state materials. Among the fascinating properties are so-called breathing and swelling phenomena as a function of host–guest interactions. Phase transitions are triggered by guest adsorption/desorption, photochemical, thermal, and mechanical stimuli. Other important flexible properties of MOFs, such as linker rotation and sub-net sliding, which are not necessarily accompanied by crystallographic phase transitions, are briefly mentioned as well. Emphasis is given on reviewing the recent progress in application of in situ characterization techniques and the results of theoretical approaches to characterize and understand the breathing mechanisms and phase transitions. The flexible MOF systems, which are discussed, are categorized by the type of metal-nodes involved and how their coordination chemistry with the linker molecules controls the framework dynamics. Aspects of tailoring the flexible and responsive properties by the mixed component solid-solution concept are included, and as well examples of possible applications of flexible metal–organic frameworks for separation, catalysis, sensing, and biomedicine.
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Music, Omer. "Flexible asymmetric spinning." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609554.
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Abrari, Farid. "Multi-axis milling of flexible parts /." *McMaster only, 1998.
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Farshbaf, Mohamad Reza. "Mixed metal forming/machining flexible manufacturing system." Thesis, Open University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277924.
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Elghawail, Ali Mohamed. "Flexible forming of 3-D metal panels." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8252/.
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The process of sheet metal forming is commonly used to create 3-D surfaces in, e.g., aircrafts and automobiles. Stamping is one of most common sheet metal forming processes but traditional forming processes which have been developed for mass production are inflexible and expensive, and economically unsuitable for small-scale production. More appropriate for small-batch and prototype production are flexible forming methods such as multi-point forming (MPF) which have been developed in recent years. A pair of opposed reconfigurable tools containing pin matrices could replace traditional solid stamping tools. Based on this technique, the construction of sheet metal forming tools becomes flexible and fast. Springback, caused by elastic recovery and release of residual stress, is an unavoidable issue in all sheet metal forming and significantly affects the geometrical precision of the products. Springback is a defect, and if it is beyond permissible tolerance it will adversely affect the assembly process such as distortion of sub-assemblies and poor fit-up during welding. Estimation of springback remains an important and challenging issue for the sheet metal industry. Based on the ABAQUS software, 3-D finite element models were generated, with the required constraints and boundary conditions described and applied in the simulation. The process of multi-point forming and springback were simulated by combining explicit and implicit algorithms. The influence of some significant working parameters, such as radius of forming curvature, blank holder force and elastic cushion thickness on final product quality (springback, thickness variation and wrinkling) has been investigated.
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Mendes, Ricardo Faria. "Metal-organic frameworks based on flexible bridges." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22468.
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Doutoramento em QuímicaEsta tese pretende apresentar o trabalho desenvolvido na preparação de novos Polímeros de Coordenação ou Redes Metalo-Orgânicas de baixa dimensão (1D e 2D) pela auto-montagem de lantanídeos e ligandos orgânicos altamente flexíveis. Numa primeira etapa as condições ideais foram optimizadas utilizando abordagens sintéticas distintas: condições hidrotérmicas e de one-pot, o que permitiu o isolamento de cristais grandes; e a síntese por microondas, que foi a abordagem ideal para reduzir significativamente o tempo de reacção. Todos os materiais foram caracterizados utilizando a combinação de várias técnicas, como FTIR, análise elementar, RMN de estado sólido, microscopia electrónica (SEM e EDS) e termogravimetria. As estruturas cristalinas foram resolvidas utilizando análise de difracção de raios X de cristal único. Num segundo passo, os materiais de baixa dimensão foram utilizados como precursores para obter MOFs de dimensão superiores por transformação Cristal- Cristal, que foram seguidos de perto por análise de raios-X de cristal único. No último passo, as propriedades de alguns materiais foram investigadas, como o uso como potencial catalisadores heterogéneos e como condutores protónicos. Alguns materiais mostraram actividade catalítica notável em várias reacções orgânicas, enquanto um mostrou a maior condução protónica registada até agora para qualquer tipo de material.
This thesis aims to present the work developed in the preparation of new Coordination Polymers or Metal-Organic Frameworks with low dimensions (1D and 2D) by the self-assembly of lanthanides and highly flexible organic linkers. In a first step the ideal conditions were screened using distinct synthetic approaches: hydrothermal and one-pot conditions, which allowed the isolation of large crystals; and microwaveassisted synthesis, which was the ideal approach to reduce significantly the time of reaction. All materials were characterized using the combination of several techniques, such as FTIR, elemental analysis, solid-state NMR, electron microscopy (SEM and EDS) and thermogravimetry. The crystal structures were unveiled using singlecrystal X-ray diffraction analysis. In a second step, the low dimensional materials were used as precursors to obtain higher dimensional MOFs by Single-Crystal to Single-Crystal transformation, which were followed closely by single-crystal X-ray analysis. In a final step, the properties of some materials were investigated, with potential use as heterogeneous catalysts and proton conductors. Some materials showed remarkable catalytic activity in several organic reactions, while one showed the highest proton conduction registered up to now for any kind of material
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Hong, Jinchul 1977. "Numerical models for scoring failures of flexible metal to metal face seals." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30339.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaves 106-108).
The flexible metal to metal face seals (FMMFS) has unique features including much more flexibility in the circumferential direction than in the radial direction, identical rotating and stationary seals, and a loading mechanism using elastomeric rings. This thesis work is the first attempt to explain scoring failures of this unique type of mechanical face seal. Numerical models and new scoring failure criteria were developed to explain different scoring failures of the FMMFS. The numerical models consider interactions among seal surface deflections, lubrication in the sealing band and thermal effects simultaneously. The numerical models were validated from comparisons with experiments and applied to scoring failure tests. The new scoring failure criterion successfully predicted the likelihood of scoring failures for each seal pair at given loads and speeds. From in-depth analysis of the seal pairs with low and high scoring failure speeds, it has been shown that discontinuous contact patterns can increase scoring resistance of the seal pair. These discontinuous contact patterns are created by irregular surface profiles of the sealing band. Irregular surface profiles can decrease high temperature regions by reducing superposition of temperatures and thermal conduction resistance, and finally delay scoring failures.
by Jinchul Hong.
Ph.D.
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Hirvi, Johan. "Long Span Flexible Metal Culverts Ultimate Load Calculations." Thesis, KTH, Bro- och stålbyggnad, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36938.
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Ouja, Najib. "Molecular simulation of flexible helical metal-organic frameworks." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/2235/.
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In this work, force fields were developed to model flexible helical metalorganic framework solids (MOFs). Since no suitable force fields to model flexible MOFs had been reported, the study began by benchmarking an existing organic force field, CHARMM22, against Ni3(BTC)2(pyridine)6(4,5octanediol) 3. CHARMM22 force filed did produce a framework that retained its original threedimensional structure for the duration of the simulations, and did so at experimentally relevant temperatures provided a minimum number of 20 solvent molecules per unit cell were included. However, important inadequacies were found between the experimental crystal structure and the simulated one. Therefore a series of refinements of the force field were performed. The three best modified force fields were then used to simulate this MOF and a detailed analysis of its physical properties produced. A key conclusion from the development and testing cycle was that hydrogen bonding between the BTC and the hydroxyl groups of both the solvent and the framework alcohol molecules played a critical role in stabilizing the MOF. The transferability of these forcefields was tested against two new MOFs, for which experimental crystal structures had been reported: Ni3(BTC)2(pyridine)6(2,3butanediol) 3 (called MOF4) and Ni3(BTC)2(pyridine)6(1,2,6hexanetriol) 3 (called MOF6). One forcefield was found to give a good description of MOF4. For MOF6 however, competition for framework bonding between the diol and terminal hydroxyl group on the hexanetriol destabilized the framework with all three force fields. A stable MOF was produced only when the NiOT bond lengths were constrained to the experimental values. It was concluded that polarisation of ligand donor atoms by the Ni2+ needed to be incorporated in any future refinements of the forcefield. Finally, this study showed that the Ni3(BTC)2(pyridine)6(4,5octanediol) 3 MOF can display enantioselective properties. Solvent alcohol molecules of the same enantiomeric form as that incorporated into the framework were found to interact much more strongly with the framework than their enantiomer, and even formed enantiomer specific hydrogen bonds with the framework. Structural differences were also observed in solventBTC, solventNi and solvent pyridine geometries.
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Narayanan, Sudarshan. "Metal-Polymer Hybrid Materials for Flexible Transparent Conductors." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/469.
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Perkins, Catherine. "Synthesis, characterisation and properties of flexible metal-organic frameworks." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/12615/.
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In this thesis the synthesis, characterisation and analysis of new Metal-Organic Frameworks (MOFs) are presented. Introduction: Chapter 1 includes an overview of recent literature focusing on the potential application of porous MOFs. Synthetic and Experimental Techniques: Chapter 2 contains information regarding the synthesis of the organic ligand, tetrakis-(4-carboxyphenyl)-benzene (H4TCPB) and solvothermal MOF synthesis. Characterisation techniques used in this thesis are also explained. Mixed Carboxylate-Imidazole Based Metal-Organic Frameworks: In chapter 3, the synthesis of MOFs containing ligands with both imidazole and carboxylate functionality are presented. The MOFs produced are based on metal-carboxylate coordination networks with imidazole coordinated as a terminal, neutral ligand in all cases. An investigation into how reagent ratio and addition of base affects the product of reaction with the combination of Co(II), 1,3,5-benzene tricarboxylate and imidazole yields three different frameworks from the same three reagents. The main compound discussed has the formula Co3(BTB)1.5(IM)1.35(O)0.5(OH)0.5(H2O)1.65·guests and is based on a novel Co6 building unit which comprises neutral imidazole, oxo, hydroxo and carboxylate coordination. This Co6 unit is the basis of a 2D tri-layer, stacked into a 3D porous arrangement via π···π stacking interactions between 1,3,5-benzene tribenzoate ligands. This material was characterised to be permanently porosity towards N2, CO2 and CH4, however the material is sensitive to activation conditions, presumably due to the reliance on weak π···π stacking interactions between imidazole ligands to retain the void space. A Cerium-Based Metal-Organic Framework: Structure, Sorption and Structural Transformations upon Desolvation: In chapter 4, a 3D framework based on Ce(III) and H4TPCB with the formula Ce(HTCPB)"guests is presented. A variable temperature single crystal x-ray diffraction experiment allowed four structures to be determined from the same parent material: The as-made structure, the partially desolvated structure in which all channel and coordainted H2O has been removed but coordinated EtOH remains, the fully desolvated structure and the structure following re-exposure of the desolvated phase to air. Powder x-ray diffraction confirms that the phase changes observed occur in both the single crystal and bulk crystalline phases. A gas cell experiment on the rearranged phase shows that the material can reversibly uptake Xe into the channels. This investigation highlights the structural stability and flexibility of 11. ii! ! Ce(HTCPB) for Xylene Separation and Analysis of Uptake of Aromatic Guests: In chapter 5, Ce(HTCPB) is investigated for its potential in xylene separation and shows para-/meta-xylene (pX/mX) selectivity in line with the highest performing MOF and zeolite materials. Analysis of the para-, meta-, ortho-xylene (oX) and ethylbenzene (EB) loaded single crystal structures provides an insight into the preference of the material for pX over the other isomers. The framework relaxes favourably around the pX isomer, which forms C-H···π and C-H···O interactions with the channel walls, forming an almost perfect pX pocket. Such interactions are formed to a lesser extent with the other less streamlined guests. Single crystals of Ce(HTCPB) are also loaded with benzene and toluene in for comparison with the pX loaded structure. A Series of Isostructural Lanthanide-Based MOFs for Xylene Separation and A Framework using a Smaller Lanthanide: In chapter 6, a series of compounds isostructural with Ce(HTPCB) are presented with the formula Ln(HTPCB), where Ln = La, Ce, Pr, Nd and Sm. The single crystal structures of the desolvated and rearranged phases were also determined to be isostructural with the corresponding Ce(HTCPB) phases. These compounds were investigated for their pX/mX selectivities, with Pr, Nd and Sm(HTCPB) producing selectivities around 50 % higher than any reported MOF or zeolite material. Analysis of the pX and mX loaded single crystal structures of this series of compounds provided an understanding of the trend in selectivity observed. Also in this chapter, combination of H4TCPB with a smaller lanthanide, Yb, produced a new framework.
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Hoffmann, Herbert C. "NMR-SPEKTROSKOPIE AN FLEXIBLEN UND CHIRALEN METAL-ORGANIC FRAMEWORKS (MOFs)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-149597.
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Es wurden verschiedene NMR-spektrokopische Messungen an flexiblen und chiralen MOFs durchgeführt. Zur Untersuchung der Porensysteme kamen 129Xe-NMR und 13C-NMR an adsorbiertem CO2 zum Einsatz, während die MOF-Gitter und ihre Wechselwirkungen mit adsorbierten Gastmolekülen mittels 13C- und 1H-MAS-NMR-Spektroskopie studiert wurden. Während DUT-8(Ni) Flexibilität zeigt, weist DUT-8(Cu) ein starres Gitter auf. Die Flexibilität der sogenannten Solid-Solutions hängt in ausgeprägter Weise vom Verhältnis der funktionalisierten bdc-Linker 2,5-bme-bdc und db-bdc ab. Dieses Verhältnis hat zudem einen großen Einfluss auf die Orientierung der adsorbierten CO2-Moleküle. Es wurde erstmals eine Methode vorgestellt, die den Festkörper-NMR-spektroskopischen Nachweis chiraler Seitengruppen in chiralen MOFs erlaubt, wie anhand des chiral modifizierten UMCM-1 (ChirUMCM-1) demonstriert wurde. Die Chiralität kann einen NMR-spektroskopisch messbaren Einfluss auf die intrinsische Dynamik des MOF-Gitters ausüben, wie am chiral modifizierten DUT-32 deutlich wurde, dessen chirale Seitengruppe selektiv 15N- und 13C-isotopenmarkiert wurde.
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Grünker, Ronny, Irena Senkovska, Ralf Biedermann, Nicole Klein, Martin R. Lohe, Philipp Müller, and Stefan Kaskel. "A highly porous flexible Metal–Organic Framework with corundum topology." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138599.
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A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFsDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Krause, Simon [Verfasser]. "Negative Gas Adsorption of Flexible Metal-Organic Frameworks / Simon Krause." München : Verlag Dr. Hut, 2019. http://d-nb.info/1219178330/34.
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Grünker, Ronny, Irena Senkovska, Ralf Biedermann, Nicole Klein, Martin R. Lohe, Philipp Müller, and Stefan Kaskel. "A highly porous flexible Metal–Organic Framework with corundum topology." Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27762.
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A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Bond, Philip Harvey. "Analysis of flexible interlayers between metals and ceramics." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282713.
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Dickson, Sara-Jane. "Flexible podand and metal-based hosts for anion binding and sensing." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2263/.
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A series of amino-pyridyl and aminomethyl-pyridyl ligands, all with both pyridyl and secondary amine functionalities have been synthesised. A new series of organic and metal- based derivatives of these ligands have been prepared, along with the preparation of an organic viologen host, with previously reported urea arms,(^1) and the properties of these new compounds, and in particular their anion binding behaviour have been studied. The 3-aminomethyl-pyridyl ligands interact with transition metals and anions, in both solution and the solid state. They showed a particular affinity for copper(II) salts, and a nitrate sensing system has been prepared using the Ligands fluorescence, through the addition of copper to a solution of the photo-active aminomethyl-pyridyl ligand. However, the active species has proved difficult to characterise. Ruthenium-based derivatives have been shown to form both 1:1 and 2:1 host: guest complexes with a variety of anions. These compounds have also shown an equilibrium in which anion binding promotes time-averaging of diastereotopic methylene protons. The addition of anions to the fluorescent sensing analogues has shown quenching of the fluorescence. Organic systems involving amino-pyridyl ligands around a di- and tri-substituted aryl core bind anions in solution. The fluorescent pyrene-derived host shows 2:1 host: guest binding in NMR spectroscopic studies, which is in contrast to work on aryl derivatives and previous work on anthracene containing hosts,(^2) which has shown 1:1 host: guest binding. Organic viologen compounds with urea arms and a control compound with pyridyl arms, show a colourimetric response to carboxylates, although in the presence of oxygen, decomposition occurs. These hosts also show an affinity for halide anions, which do not bring about this colourimetric response.
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Rogers, Pamela Rose Patterson White Richard E. "An empirical investigation of manufacturing flexibility and organizational performance as moderated by strategic integration and organizational infrastructure." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-11065.
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Graver, Thomas William. "Determination of cutting-tool inventory levels in a flexible manufacturing system." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/30775.
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Haddad, J. "The synthesis and characterisation of metal organic frameworks using functionalised and flexible linkers." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3015379/.
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Carrington, Elliot. "Solvent removal, gas uptake and functionalization in a continuously flexible metal-organic framework." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/11893/.
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Ousterhout, Karl Brown. "Design and control of a flexible process for three-dimensional sheet metal forming." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13460.
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Wu, Zhenkun. "Metal-reduced graphene oxide for supercapacitors and alternating current line-filters." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53941.
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We design a facile approach to investigate the role benzene derivatives play in the capacitance enhancement of graphene-based supercapacitors. The main reason is attributed to the pseudocapacitance of the aromatic molecules rather than the former one. Meanwhile, we find that the para and ortho substituted benzene derivatives contribute much more than the meta substituted ones.
In addition, we fabricate an all-solid-state flexible MSC based on metal-reduced GO. The as-fabricated MSC shows high areal capacitance and excellent reliability, which makes it a promising energy storage candidate for wearable electronics. Based on the work of MSC, we achieve a flexible ac line-filter that is not only competitive against commercial product but also suitable for mass production.
Meanwhile, we produce a three-dimensional graphene/polydimethylsiloxane composite that gives a thermal resistance as small as 14 mm2K/W, which is comparable to commercial products. What’s more, a convenient transient program that saves much time is developed to measure the thermal resistance.
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Gutiérrez, Muñoz Monserrat. "Recubrimientos multicapas de tipo orgánico/metal/cerámica para espejos solares de base polimérica flexible." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEC010/document.
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La production actuelle d’énergie qui provient principalement des combustibles fossiles a un impact négatif sur l’environnement. Le développement des énergies renouvelables peut limiter cet impact. Si la conversion thermodynamique de l’énergie solaire obtenue en concentrant le rayonnement photonique permet d’atteindre des rendements élevés, l’enjeu est de réaliser, à faible coût, de grandes surfaces de réflecteurs souples et légers ayant une excellente propriété optique réfléchissante.Dans ce travail de recherche, nous avons étudié deux types de miroirs qui entrent dans la réalisation des concentrateurs solaires. Le premier miroir est constitué d’une plaque souple en polymère très transparent (indice de transmission le plus élevé possible) sur laquelle a été déposé un film réfléchissant. Cette couche est protégée contre la corrosion et les agressions environnementales par un revêtement organique opaque élaboré en face arrière. On obtient ainsi un système polymère/métal/ film organique. Le second miroir est constitué d’un substrat opaque souple sur lequel est déposé un film réfléchissant. Une couche mince protectrice organique ou céramique, ayant un indice optique de transmission le plus élevé possible, est élaborée en face avant sur la couche réfléchissante. On obtient ainsi un système céramique/métal/ organique.Cette couche réfléchissante étant indispensable dans les deux configurations de miroir, nous avons étudié l’élaboration d’une couche réfléchissante à base d’argent du fait que la technique de dépôt chimique dynamique, appelée encore technique JetMetalTM, permet d’obtenir des films d’argent à température ambiante et de façon rapide et peu coûteuse. D’autre part, cette technologie agrée « Green Tech » est bien adaptée pour l’élaboration de dépôt sur des grandes surfaces. Ce rapport décrit les étapes et les paramètres nécessaires pour obtenir des réflecteurs optiques à base d’argent de grandes qualités : qualité optique avec des réflectivités supérieures à 95%, qualité mécanique avec des interfaces polymère/métal pouvant encaisser des déformations, un rapport qualité/prix par l’optimisation des cinétiques de dépôt et d’épaisseur de film d’argent (environ 100nm) avec un temps très court d’élaboration. De nombreuses techniques d’analyses et de caractérisations (XPS, AFM, LRX, SEM…) ont été utilisées pour dégager les paramètres pertinents d’un miroir solaire à base d’argent.La propriété optique du film d’argent est stable à l’air et avec le temps. Néanmoins, une protection de l’argent est nécessaire en particulier en face avant. Cette protection doit adhérer au film d’argent, pouvoir être flexible et présenter un indice de transmission le plus élevé possible dans le domaine visible. Si différents vernis ont été étudiés, notre travail a surtout porté sur l’élaboration de revêtements protecteurs organiques (PMMA, PU), céramiques (SiO2, Al2O3) et surtout hybrides organique-céramique. Ce travail de recherche a permis d’identifier les domaines de pertinence de ces différents types de revêtements protecteurs sous contrainte radiative, leur compatibilité avec une couche réflective d’argent, pour conduire à des concentrateurs souples performants. Une solution originale est présentée en conclusion. Elle porte sur la réalisation d’un miroir souple élaboré sur une feuille de verre de 100 µm d’épaisseur revêtue d’un film de 100 nm d’argent. La réflectivité est supérieure à 95% dans le visibleThe present production of energy that mainly comes from the burning of fossil fuels has a negative impact on our environment. The research and development of clean and renewable sources of energy can decrease this damage. If the thermodynamic conversion from solar energy obtained by photons radiation concentration allows us a higher efficiency, the challenge is to build at low cost, large areas for solar reflectors that are flexible and lightweight, with a powerful optical reflection.During this research a study was made on two types of mirrors for achieving solar concentrators. The first mirror is formed of a flexible polymer plate highly transparent (Transmission index as high as possible) in which was deposited a reflective layer. This layer is protected against corrosion and any other environmental aggression by an opaque organic coating built on the rear face. This produces a polymer/metal/organic film system. The second mirrors consist of a flexible opaque substrate in which, a reflective film is deposited. A thin organic or ceramic protector film with a transmission index as high as possible is prepared in front of the reflective layer. Thereby, a ceramic/metal/organic system was obtained.Being that the reflective layer is essential in both configurations of the mirror, research was carried out about the development of a reflective layer composed of silver with the dynamic chemical plating technique also called “Jet MetalTM technique” which allows the elaboration of silver films at room temperature in a fast and economical manner. Also, this approved technology <> is well adapted for the deposit development over large surfaces. This report describes the steps and necessary parameters to obtain optical reflectors based on high quality silver: optical quality with a higher reflectivity over 95%, mechanical quality with interfaces of polymer / metal that can absorb deformations, a relation quality/price through the optimization of the deposit kinetic and the silver film thickness (approximately 100 nm) with a very short elaboration time. Many analysis and characterization techniques (XPS, AFM, LRX, SEM…) have been performed to determine the parameters of a solar mirror made of silver.The optical property of the silver film is stable in air ambient and with time. However; the silver protection is necessary mainly on the front face. This protection must adhere to the silver film, be flexible and provide a high visual range. Different varnishes have been researched, and our work has been concentrated in the development of organic (PMMA, PU), ceramics (SiO2, Al2O3), and especially hybrid organic-ceramic covering protection. This research allowed us to identify the relevant areas of these different types of protection coatings under radiation stress, its compatibility with the silver layer to obtain efficient and flexible concentrators. An original solution is presented at the conclusion that corresponds in the elaboration of a flexible mirror, made up of a glass layer of 100 µm thick and covered in a silver film of 100 nm. The reflection is over 95% visible
La producción actual de energía que proviene principalmente de combustibles fósiles tiene un impacto negativo sobre el medio ambiente. El desarrollo de las energías renovables puede reducir este impacto. Si la conversión termodinámica de la energía solar obtenida por concentración de radiación de fotones permite alcanzar altos rendimientos, el reto es lograr realizar, a bajos costos, grandes áreas de reflectores flexibles y ligeros, con una excelente propiedad óptica reflejante.En esta investigación, se estudiaron dos tipos de espejos que intervienen en la consecución de los concentradores solares. El primer espejo está hecho de una placa flexible de polímero altamente transparente (índice de transmisión lo más alta posible) en el que se depositó una película reflejante. Esta capa está protegida contra la corrosión y el ataque del medio ambiente por un revestimiento orgánico opaco desarrollado en la parte trasera. Esto produce un sistema polímero/metal / película orgánica. El segundo espejo consiste en un sustrato opaco flexible en la que se deposita una película reflejante. Una película delgada y protectora orgánica o cerámica con un índice de transmisión lo más alto posible se prepara en frente de la capa reflejante. Por lo tanto, se obtiene un sistema cerámico / metal / orgánico.Siendo esta capa reflejante esencial en ambas configuraciones de espejo, se investigó el desarrollo de una capa reflejante a base de plata con la técnica de depósito químico dinámico, también llamada “JetMetalTM technique” que permite elaborar películas de plata a temperatura ambiente de manera rápida y económica. Además, esta tecnología, aprobada « Green Tech », está bien adaptada para el desarrollo de depósitos sobre superficies grandes. Este trabajo describe los pasos y los parámetros necesarios para obtener reflectores ópticos basados en plata de grandes cualidades: calidad óptica con reflectividad mayor a 95%, calidad mecánica con interfaces de polímero / metal que pueden absorber deformaciones, una relación calidad / precio mediante la optimización de la cinética de depósito y espesor de la película de plata (aproximadamente 100 nm) con un tiempo corto de elaboración. Numerosas técnicas de análisis y caracterización (XPS, AFM, LRX, SEM ...) han sido utilizadas para determinar los parámetros pertinentes de un espejo solar a base de plata. La propiedad óptica de la película de plata es estable en el aire y en el tiempo. Sin embargo, la protección de la plata es necesaria, en particular en el frente. Esta protección debe adherirse a la película de plata, ser flexible y proporcionar un índice de transmisión lo más alto posible en el rango visible. Se han estudiado diferentes barnices y nuestro trabajo ha sido centrado en el desarrollo de recubrimientos de protección orgánicos (PMMA, PU), cerámicos (SiO2, Al2O3) y especialmente en híbridos orgánico-cerámica. Esta investigación ha permitido identificar las áreas de relevancia de estos diferentes tipos de recubrimientos de protección bajo estrés por radiación y su compatibilidad con una capa reflejante de plata para obtener concentradores flexibles eficientes. Una solución original se presenta en la conclusión y corresponde en la realización de un espejo flexible elaborado en una hoja de vidrio de 100 µm de espesor y recubierto con una película de plata de 100 nm. La reflectividad es superior a 95% en el visible
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Chikkali, Samir H. "Complexes of flexible ditopic catechol phosphines synthesis, metal assisted self-assembly and catalytic application /." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-33884.
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Pavanello, Fabio. "Uni-travelling carrier photodiodes and metal mesh filters based on sub-wavelength apertures for THz applications." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10172/document.
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Le grand intérêt des fréquences THz (0.1-10 THz) pour l’imagerie, la spectroscopie et les communications sans fils a conduit à un important développement de dispositifs pour la génération et la détection d’ondes THz. Les photodiodes à transport unipolaire font partie des principales sources grâce à leur comportement large bande (0-3 THz), leur fonctionnement à température ambiante, leur longueur d’opération à 1.55 µm et leur taille compacte. Le plus grand inconvénient est la leur faible puissance RF générée à haute fréquence (ordre du µW à 1 THz). Une technique pour l’augmenter consiste à utiliser des puissances optiques en entrée plus élevées. Par contre, cette solution peut conduire à leur destruction due à l’échauffement, surtout en cas d’absorption non voulue.Dans la première partie de la thèse un contact électrique basé sur un réseau sub-longueur d’onde a été développé pour réduire ce problème. Cette solution donne des bonnes propriétés électriques, optiques et thermiques avec un procédé plus simple en termes de fabrication et caractérisation par rapport aux travaux précédents.Un deuxième inconvénient est relié à leur caractère non-linéaire qui conduit à un bruit à basse fréquence à cause du large spectre des sources optiques. Ce problème est critique dans le cas de mesures à haute fréquence avec des détecteurs incohérentes car les puissances RF sont très faibles.Dans la deuxième partie de la thèse un filtre passe-haut avec une haute transparence et large bande a été développé sur un diélectrique avec faible pertes aux fréquences THz. Le procédé développé peut être utilisé pour des dispositifs en espace libre grâce aux propriétés optique du diélectriqueThe increasing interest in the THz region (0.1-10 THz) for applications like imaging, spectroscopy and wireless communications is leading to a strong development of devices for the generation and detection of THz waves. Uni-travelling carrier photodiodes (UTC-PDs) are one of the main sources due to their broadband behavior (0-3 THz), room temperature operation, driving wavelength of 1.55 µm and compactness. Their main drawback comes from the low output RF powers at high frequencies (order of µW at 1 THz). A technique to increase their RF powers consists in using higher optical driving powers. However, this solution may lead to their failure because of heating, especially in case of unwanted absorption.In the first part of the thesis an electrical contact based on sub-wavelength apertures has been developed to reduce this issue. This solution has been shown valuable under multiple aspects. It provides good electrical, optical and thermal properties, while leading to an easier process in terms of fabrication and characterization with respect to previous works.A second drawback of UTC-PDs is due to their non-linear behavior which leads to a noise at low frequency because of the broad spectrum of the driving optical signals. This issue is critical for measurements at high frequencies with incoherent detectors due to the low RF powers to be detected.In the second part of the thesis a high-transparency broadband high-pass mesh filter has been developed on a novel low-loss dielectric material to filter-out this noise. The developed process can be exploited in other free-space devices like metamaterials due to the remarkable properties of this dielectric at THz frequencies
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Millan, Simon [Verfasser]. "Kristalline pyrazolhaltige Netzwerkstrukturen: Von flexiblen Metall-organischen Gerüstverbindungen zu Polymorphen / Simon Millan." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2021. http://d-nb.info/1229691790/34.
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Ries, Jana. "Instance-based flexible parameter tuning for meta-heuristics using fuzzy-logic." Thesis, University of Portsmouth, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515539.
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Hamilton, Kent Anthony. "Improvements to the Design of a Flexible Diaphragm for use in Pressure Wave Generators for Cryogenic Refrigeration Systems." Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/7950.
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Low cost cryocoolers suitable for long term use in industrial environments are required for superconducting technologies to be competitive with copper based devices in real world applications. Industrial Research Limited is developing such cryocoolers, which use metal diaphragm based pressure wave generators to convert electrical energy to the gas volume displacement required. This project explores methods of increasing the volume displacement provided by the diaphragms while ensuring the components stay within the acceptable material limits.
Various alternative diaphragm shapes are tested against the currently used shape through finite element analysis. In addition to testing alternative diaphragm shapes, each shape’s dimensions are optimised. It is concluded the currently used design can be improved by offsetting the piston rest position and slightly reducing the piston diameter.
A more detailed analysis is carried out of the bend radii created during fabrication of the diaphragm, and physical testing is performed to verify unexpected calculated stress concentrations. High stresses are observed, however it is concluded unmodelled material features have a large effect on the final stress distribution.
It is recommended advantageous shape changes calculated in the first part of the work be trialled to increase the efficiency of the cryocooler, and that investigation of the material behaviour during commissioning of the pressure wave generator be carried out to better understand the operational limits of the diaphragms.
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Rodrigues, Americo Joao Claudio. "Un meta-modèle de composants pour la réalisation d'applications temps-réel flexibles et modulaires." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM055/document.
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La croissante complexité du logiciel a mené les chercheurs en génie logiciel à chercher des approcher pour concevoir et projéter des nouveaux systèmes. Par exemple, l'approche des architectures orientées services (SOA) est considérée actuellement comme le moyen le plus avancé pour réaliser et intégrer rapidement des applications modulaires et flexibles. Une des principales préocuppations des solutions en génie logiciel et la réutilisation, et par conséquent, la généralité de la solution, ce qui peut empêcher son application dans des systèmes où des optimisation sont souvent utilisées, tels que les systèmes temps réels. Ainsi, créer un système temps réel est devenu très couteux. De plus, la plupart des systèmes temps réel ne beneficient pas des facilités apportées par le genie logiciel, tels que la modularité et la flexibilité. Le but de cette thèse c'est de prendre en compte ces aspects temps réel dans des solutions populaires et standards SOA pour faciliter la conception et le développement d'applications temps réel flexibles et modulaires. Cela sera fait à l'aide d'un modèle d'applications temps réel orienté composant autorisant des modifications dynamiques dans l'architecture de l'application. Le modèle de composant sera une extension au standard SCA qui intègre des attributs de qualité de service sur le consomateur et le fournisseur de services pour l'établissement d'un accord de niveau de service spécifique au temps réel. Ce modèle sera executé sur une plateforme de services OSGi, le standard de facto pour le developpement d'applications modulaires en JavaThe increase of software complexity along the years has led researchers in the software engineering field to look for approaches for conceiving and designing new systems. For instance, the service-oriented architectures approach is considered nowadays as the most advanced way to develop and integrate fastly modular and flexible applications. One of the software engineering solutions principles is re-usability, and consequently generality, which complicates its appilication in systems where optimizations are often used, like real-time systems. Thus, create real-time systems is expensive, because they must be conceived from scratch. In addition, most real-time systems do not beneficiate of the advantages which comes with software engineering approches, such as modularity and flexibility. This thesis aim to take real time aspects into account on popular and standard SOA solutions, in order to ease the design and development of modular and flexible applications. This will be done by means of a component-based real-time application model, which allows the dynamic reconfiguration of the application architecture. The component model will be an extension to the SCA standard, which integrates quality of service attributs onto the service consumer and provider in order to stablish a real-time specific service level agreement. This model will be executed on the top of a OSGi service platform, the standard de facto for development of modular applications in Java
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Renaudo, Erwan. "Des comportements flexibles aux comportements habituels : meta-apprentissage neuro-inspiré pour la robotique autonome." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066508/document.
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Dans cette thèse, nous proposons d'intégrer la notion d'habitude comportementale au sein d'une architecture de contrôle robotique, et d'étudier son interaction avec les mécanismes générant le comportement planifié. Les architectures de contrôle robotiques permettent à ce dernier d'être utilisé efficacement dans le monde réel et au robot de rester réactif aux changements dans son environnement, tout en étant capable de prendre des décisions pour accomplir des buts à long terme (Kortenkamp et Simmons, 2008). Or, ces architectures sont rarement dotées de capacités d'apprentissage leur permettant d'intégrer les expériences précédentes du robot. En neurosciences et en psychologie, l'étude des différents types d'apprentissage montre pour que ces derniers sont une capacité essentielle pour adapter le comportement des mammifères à des contextes changeants, mais également pour exploiter au mieux les contextes stables (Dickinson, 1985). Ces apprentissages sont modélisés par des algorithmes d'apprentissage par renforcement direct et indirect (Sutton et Barto, 1998), combinés pour exploiter leurs propriétés au mieux en fonction du contexte (Daw et al., 2005). Nous montrons que l'architecture proposée, qui s'inspire de ces modèles du comportement, améliore la robustesse de la performance lors d'un changement de contexte dans une tâche simulée. Si aucune des méthodes de combinaison évaluées ne se démarque des autres, elles permettent d'identifier les contraintes sur le processus de planification. Enfin, l'extension de l'étude de notre architecture à deux tâches (dont l'une sur robot réel) confirme que la combinaison permet l'amélioration de l'apprentissage du robotIn this work, we study how the notion of behavioral habit, inspired from the study of biology, can benefit to robots. Robot control architectures allow the robot to be able to plan to reach long term goals while staying reactive to events happening in the environment (Kortenkamp et Simmons, 2008). However, these architectures are rarely provided with learning capabilities that would allow them to acquire knowledge from experience. On the other hand, learning has been shown as an essential abiilty for behavioral adaptation in mammals. It permits flexible adaptation to new contexts but also efficient behavior in known contexts (Dickinson, 1985). The learning mechanisms are modeled as model-based (planning) and model-free (habitual) reinforcement learning algorithms (Sutton et Barto, 1998) which are combined into a global model of behavior (Daw et al., 2005). We proposed a robotic control architecture that take inspiration from this model of behavior and embed the two kinds of algorithms, and studied its performance in a robotic simulated task. None of the several methods for combining the algorithm we studied gave satisfying results, however, it allowed to identify some properties required for the planning process in a robotic task. We extended our study to two other tasks (one being on a real robot) and confirmed that combining the algorithms improves learning of the robot's behavior
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TERRUZZI, STEPHANIE. "MULTIVARIATE FLEXIBLE METAL ORGANIC FRAMEWORKS: THE ROLE OF FUNCTIONALIZED LINKERS, HETEROGENEITY AND DEFECTS IN ADSORPTION PROCESSES." Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/933630.
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Metal-Organic Frameworks (MOFs) are a class of synthetic porous crystalline materials based on metal ions connected through spacing ligands. They possess interesting properties such as, high porosity, high concentration of metal centers, flexibility, etc., which are difficult to find in conventional porous materials. As a result of these unique features, MOFs can maintain porous structures upon removal, inclusion, exchange, or reaction of a wide selection of molecular guests, making them useful for applications in selective gas adsorption/separation. Furthermore, a number of MOFs have the ability to respond to specific stimuli such as host-guest interactions, temperature or pressure change, light, etc. To date, most of the applications of these flexible MOFs is related to gas-storage and selective adsorption/separation, but it was soon recognized that the responsive properties of these materials have enormous potential in many areas, a really interesting example are NPs@MOFs composites which can be used to design novel “smart” heterogeneous catalysts capable of reversibly adapt to substrates and/or respond to regulating stimuli (e.g. reversible structural transitions upon adsorption of guest molecules). The work within this thesis is divided into two parts. The first one focuses on the understanding of the host-guest interactions during adsorption processes in highly stable, rigid, porous metal-organic frameworks. of formula Fe2(BDP)3x(BDP-NH2)3(1-x) (x = 0, 0.5, 1) with H2BDP-NH2 = 2-amino[1,4-bis(1Hpyrazol- 4-yl)benzene]. Their investigation was performed through a multi-technique approach exploiting high-resolution powder X-ray diffraction (HR-PXRD), advanced gas adsorption measurements and Monte Carlo simulations. In particular, the host-guest interactions during CO2 adsorption were studied via in situ HR-PXRD dosing CO2 in certain pressure ranges at different temperatures and compared between functionalized and bare systems. Rietveld refinements of the diffraction data collected at each pressure point was used to understand the preferential adsorption sites occupied by the gaseous probe and the host–guest interactions, as well as the breathing behaviour, whose mechanism was not yet completely described in the literature. The metal ion and ligand functionalization modulate the sorption properties of these materials, enhancing their affinity to CO2 molecules. Finally, new flexible, multivariate MOFs of general formula Zn(BDP)0.5(BDP-X)0.5 (X = NH2 or NO2) were synthesized. The deep characterization of the adsorption properties and the structural features of these materials will be crucial to understand the relation between the structural flexibility, functionalization degree and crystal size, with the gas adsorption and separation properties. The second part of this thesis describes a family of pillar-layered MOFs of general formula [M2(fubdc) 2P]n with M2+ = Zn2+, fu-bdc2- = diversely functionalised 1,4-benzenedicarboxylate) and how catalytically inert nanoparticles (silica NPs, 30 nm) can be embedded into the microporous ordered MOFs structures, obtaining hybrid materials where the NPs represent typically a meso-scale “defect” or “heterogeneity” to the system. In particular, the work was focused on the comparison between the plain MOFs and the new composite materials NPs@MOF. The parent [Zn2(bdc)2(dabco)]n is only weakly flexible, whereas the substituted frameworks [Zn2(fu-bdc)2(dabco)]n (with fu = DM, 2,5-bis(methoxy)- 1,4-benzenedicarboxylate or BME, 2,5-bis(2-methoxyethoxy)-1,4-benzenedicarboxylate) contract significantly upon guest removal to a narrow pore (np) form and expand again (lp form) upon adsorption of DMF, EtOH, or CO2, etc. In contrast, N2 is hardly adsorbed and does not open the narrow pore form. These “breathing” dynamics are attributed to the dangling side chains present on the linkers, which interact with mobile guest molecules as well as with themselves and with the framework backbone. The samples were characterized by a variety of techniques: PXRD, FTIR, TGA, DSC, EFTEMEDX, TEM tomography, UV-Vis and PL spectroscopy, standard N2 (77 K) and CO2 (195 K) gas adsorption experiments with the objective of understanding the connection between defects, disorder with flexibility. The in‐depth and in situ structural and spectroscopic characterization carried out, especially gas adsorption and variable temperature PXRD experiments, revealed interesting differences in the flexible behaviour between the parent MOFs and the NPs@MOFs.
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Liles, Howard J. "High throughput profile millling for the flexible and accelerated processing of electric steels." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47628.
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The proliferation of electric machines has drastically increased in recent years and is likely to increase into the future. This interest in the production of advanced, high power density electrical machines that are small in size has heightened the need for flexible manufacturing processes to produce their laminated components during short batch and prototyping production runs. A means of cost effective, accelerated prototyping of these machines will have a substantial impact on their design and optimization, reducing time requirements to produce and test a given design. A review of the current manufacturing methods for prototyping electric machines was conducted. In particular, laser cutting, electric discharge machining, and abrasive waterjet (AWJ) machining were researched as competitive processes. Each of these methods exhibits marked advantages and disadvantages that present the opportunity for a new process to compete. This work investigates the applicability of high throughput profile milling (HTPM) for the prototyping of advanced electric machines, specifically, the process parameter space for milling of electrical steels. The material response will be determined by characterizing its specific cutting energy and utilizing this to develop a model to predict cutting forces during the milling process. Optimal process parameters will be investigated to obtain maximum productivity and minimal burr formation. Finally, the impact of HTPM processing on the magnetic properties of electrical steels will be compared to that of a leading prototyping technology, AWJ machining.
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Shelton, Travis Edward. "Synthesis and Characterization of Crystalline Transition Metal Dichalcogenides onto Stretchable Substrates by Laser Processing." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1450405970.
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Yeager, John David. "Design and development of metal-polymer film systems for flexible electrodes used in cortical mapping in rats." Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/j_yeager_070908.pdf.
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Thesis (M.S. in materials science and engineering)--Washington State University, August 2008.Title from PDF title page (viewed on Mar. 11, 2009). "School of Mechanical and Materials Engineering." Includes bibliographical references.
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De, Silva Gardiyawasam L. Thushani Thilanjani. "ALL SOLID-STATE FLEXIBLE SUPERCAPACITORS WITH VERTICALLY ALIGNED MULTIWALLED CARBON NANOTUBES (MWCNT) SYNTHESIZED DIRECTLY ON METAL FOIL." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2588.
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This work is mainly focused on the investigation on all solid-sate flexible supercapacitors using MWCNT directly grown on Inconel foil. Detail physical characterization of the as grown MWCNTs were performed using Scanning Electron Microscopy (SEM), Raman and Specific surface area measurement (SSA). SSA evaluated using volumetric adsorption isotherm measurements show that such MWCNTs have effective surface area of ~ 30m2/g. These as grown MWCNT on metals foils were used to fabricate the Electrochemical Double Layer Capacitors (EDLC) or Supercapacitors. A poly(vinyl alcohol)/phosphoric acid (PVA/H3PO4) polymer gel has been used as both the electrolyte and the separator. The capacitors were fabricated by dipping the as synthesized Inconel stripes in PVA/H3PO4 gel polymer and then combining two such stripes together. Several electrochemical measurements such as Cyclic Voltammetry (CV), Galvanic Charge Discharge (GCD) cycling and Electrochemical Impedance Spectroscopy (EIS) were performed on multiple devices in order to establish these structures as viable energy storage systems. Key device parameters measured and analyzed along with standard electrochemical circuit modeling indicates that these devices have Specific Capacitances (CSP) in the mF range with a low internal resistance. The low internal resistance could be a consequence of growing the MWCNTs directly on metal foils. The highest areal capacitance measured was 19.6 mF/cm2 at 1mVs-1. The flexibility and robustness of the devices were tested by performing the aforementioned measurements at different bending angles. Our measurements indicate that these devices can withstand a large number of such bending cycles (~ 2000) without losing any functionality. It was however observed that these capacitors sustain physical damage for bending cycles > 2000 cycles and loose ~50% of their capacitance values. A detailed energy density and power density analysis confirmed that the performance of these devices is in the rage of Supercapacitors. The device parameters can be further improved by thermal annealing of the as grown electrodes in air. A summary of the comparison with other work is also presented.
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Kishida, Keisuke. "Studies on Synthesis of Flexible Microporous Coordination Polymers and Ethylene Separation from Gas Mixtures." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/189641.
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Alvarado, Pérez Miriam. "Development of Flexible Gas Sensors Based on Additive Fabrication Processes." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/669439.
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Els sensors de gasos s’utilitzen per a monitoritzar ambients interiors i exteriors. Algunes aplicacions comuns són per a mesurar el nivell de contaminants als carrers, els gasos alliberats per les fuites industrials i d’automòbils, els gasos a la mineria, el contingut d’alcohol en sang a través de l’alè exhalat, etc.
A mesura que creix el camp d’aplicació dels sensors de gasos, es fa necessari adaptar els sensors de gasos als nostres dispositius i pertinences diàries. Es requereixen materials mecànicament flexibles i resistents per a fabricar sensors de gasos flexibles. A banda de proves de detecció de gas, la resistència a la flexió dels sensors ha de provar-se per anomenar “flexible” a un sensor.
L’objectiu principal d’aquesta tesi és fabricar sensors de gasos flexibles mitjançant processos additius emprant òxids metàl·lics com a materials sensibles. Els sensors de gasos flexibles es varen fabricar utilitzant un substrat polimèric flexible (Kapton). Els diferents processos emprats varen ser compatibles amb la temperatura de funcionament del substrat. Entre les tècniques emprades estan la plantilla, la serigrafia, la injecció de tinta, AA-CVD. A més a més, es varen realitzar processos superficials per a millorar l’adhesió dels òxids metàl·lics al substrat polimèric. La flexibilitat dels sensors es va provar realitzant una prova de flexió cíclica.Los sensores de gas se utilizan para monitorear ambientes interiores y exteriores. Algunas aplicaciones comunes son para medir: el nivel de contaminantes en las calles, los gases liberados por los escapes industriales y de automóviles, los gases en la minería, el contenido de alcohol en la sangre a través del aliento exhalado, etc. A medida que crece el campo de aplicación de los sensores de gas, se hace necesario adaptar los sensores de gas a nuestros dispositivos y pertenencias diarias. Se requieren materiales mecánicamente flexibles y resistentes para fabricar los sensores de gas flexibles. Además de las pruebas de detección de gas, la resistencia a la flexión de los sensores debe probarse para llamar “flexible” a un sensor. El objetivo principal de esta tesis es fabricar sensores de gas flexibles a través de procesos aditivos utilizando óxidos metálicos como materiales sensibles. Los sensores de gas flexibles se fabricaron utilizando un sustrato polimérico flexible (Kapton). Los diferentes procesos empleados fueron compatibles con la temperatura de la temperatura de funcionamiento del sustrato. Entre las técnicas empleadas están la plantilla, la serigrafía, la inyección de tinta, AA-CVD. Además, se realizaron procesos superficiales para mejorar la adhesión de los óxidos metálicos al sustrato polimérico. La flexibilidad de los sensores se probó realizando una prueba de flexión cíclica.
Gas sensors are used to monitor indoor and outdoor environments. Some common applications are to measure: the level of pollutants in the streets, the gases liberated by industrial and car exhausts, gases in mining, blood alcohol content through the exhaled breath, etc. As the field of application for gas sensors is growing, it becomes necessary to adapt the gas sensors to our daily devices and belongings. This requires mechanically flexible and resistant materials to fabricate the flexible gas sensors. In addition to gas sensing tests, the resistance to bending of the sensors should be tested to call a sensor flexible. The main objective of this thesis is to fabricate flexible gas sensors through additive processes using metal oxides as sensitive materials. The flexible gas sensors were fabricated using a flexible polymeric substrate (Kapton). The different processes employed were compatible with the temperature of the operating temperature of the substrate. Among the techniques employed are stencil, screen-printing, inkjet-printing, AA-CVD. Also, surface processes were performed to improve the adhesion of the metal oxides to the polymeric substrate. The flexibility of the sensors was tested by performing a cyclical bending test.
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Hoffmann, Herbert C. [Verfasser], Eike [Akademischer Betreuer] Brunner, and Stefan [Akademischer Betreuer] Kaskel. "NMR-SPEKTROSKOPIE AN FLEXIBLEN UND CHIRALEN METAL-ORGANIC FRAMEWORKS (MOFs) / Herbert C. Hoffmann. Gutachter: Eike Brunner ; Stefan Kaskel." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://d-nb.info/1068447834/34.
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Öhlund, Thomas. "Metal Films for Printed Electronics : Ink-substrate Interactions and Sintering." Doctoral thesis, Mittuniversitetet, Avdelningen för naturvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-23420.
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A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this thesis, including conventional oven sintering, electrical sintering, microwave sintering, chemical sintering and intense pulsed light sintering. Specially designed coated papers with modified chemical and physical properties, were utilized for chemical low-temperature sintering of silver nanoparticle inks. For intense pulsed light sintering and material conversion of patterns, custom equipment was designed and built. Using the equipment, inkjet-printed copper oxide patterns were processed into highly conducting copper patterns. Custom-designed papers with mesoporous coatings and porous precoatings improved the reliablility and performance of the reduction and sintering process. The thesis aims to clarify how ink-substrate interactions and sintering methodology affect the performance and reliability of inkjet-printed nanoparticle patterns on flexible substrates. This improves the selection, adaptation, design and manufacturing of suitable substrates for inkjet-printed high conductivity patterns, such as circuit boards or RFID antennas.
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Grünker, Ronny. "Hochporöse und flexible metallorganische Gerüstverbindungen basierend auf Stickstoff-haltigen Carboxylat-Liganden." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-104535.
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Metallorganische Gerüstverbindungen (engl.: Metal-organic Framework, MOFs) haben sich in den letzten Jahren neben Zeolithen, Aktivkohlen und anderen als eine weitere Klasse poröser Materialien etabliert. Die Möglichkeit des individuellen Designs von Eigenschaften wie Porengröße und -geometrie, innerer Oberfläche und Porenvolumen, der Hydrophilie und Funktionalität machen diese Materialklasse zum Gegenstand der Forschung in den vielfältigsten Gebieten. Darüber hinaus besitzen sie unter porösen Materialien exklusiv die Eigenschaft der definierten strukturellen Flexibilität, welche in Kombination mit bereits genannten Eigenschaften eine weitere Vielzahl an neuen möglichen Anwendungen erahnen lässt.
Die Faszination dieser strukturellen Flexibilität von MOFs sowie die Möglichkeit der Kontrolle dieser Eigenschaft sollten im Fokus der Betrachtung stehen. Zur Integration von Flexibilität in dreidimensionale Netzwerke wurde als Strategie der Einsatz von semi-flexiblen Linkermolekülen gewählt. Eine potentielle Molekülklasse für diese Art der Untersuchung stellen Triarylaminverbindungen dar, da sie trotz ihrer durchgängigen sp2-Hybridisierung über ein gewisses Maß an konformeller Flexibilität verfügen. So wurde über einen präparativ sehr guten Zugang der tetrafunktionelle H4benztb-Linker (Abbildung 1a) generiert. Durch die Kombination dieser Tetracarbonsäure mit Metall-Clustern unterschiedlicher Konnektivität resultierten acht strukturell unterschiedliche MOFs, wodurch an diesen Verbindungen Aussagen über Struktur-Eigenschafts-Beziehungen getroffen werden können. Ein weiterer Schwerpunkt dieser Arbeit war die kostengünstige Darstellung komplexer nicht-kommerzieller Liganden und daraus resultierende hochporöse MOFs sowie Untersuchungen zu deren Stabilität und Speicherkapazität für verschiedene Gase im Hochdruckbereich.
Durch die Reaktion des H4benztb-Liganden mit Zinknitrat unter variierenden Synthesebedingungen konnten drei Netzwerke unterschiedlich hoher Konnektivität erhalten werden. DUT 10(Zn) (Zn2(benztb)2(H2O)2), basierend auf dem vierfach verknüpfenden dimeren Schaufelrad-Konnektor, zeigt mit einem (4,4)-Netzwerk dabei den geringsten Verzweigungsgrad. Daraus resultierend zeigt dieses Material eine sehr große strukturelle Flexibilität beim Entfernen des in den Poren vorliegenden Lösungsmittels sowie bei der Adsorption von CO2 bei -78°C bis 1 bar. Wird die Netzwerkkonnektivität durch den Einsatz eines sechsfach verknüpfenden [Zn4O]6+-Clusters erhöht, so zeigt das resultierende (4,6)-Netzwerk von DUT-13 (Zn4O(benztb)3/2) eine größere strukturelle Stabilität beim Entfernen des Lösunsgmittels sowie bei der Adsorption von Gastmolekülen im überkritischen Zustand. Für gasförmige Adsorptive zeigt das Netzwerk bei der Adsorption ein hochgradig flexibles Verhalten.
Im Fall von N2 konnte über in situ-PXRD-Physisorptionsmessungen eine bislang noch nie beobachtete kristallin-amorph-kristallin-amorph-Transformation während eines Physisorptionszyklus beobachtet werden, was zeigt, dass DUT-13 über ein sog. Formgedächtnis verfügt und nach einer Amorphisierung erneut in seine ursprüngliche kristalline Form zurückkehrt. Neben der Erhöhung der Netzwerkkonnektivität wurde auch der Einfluss der partiellen Substitution des semi-flexiblen H4benztb gegen rigide Linker auf die Netzwerkflexibilität untersucht. Durch die Copolymerisationsstrategie des H4benztb mit der starren 1,3,5-Benzentribenzoesäure (H3btb) konnte DUT 25 (Zn4O(btb)2/3(benztb)) erhalten werden. Aufgrund der geringen Erhöhung der Rigidität der Verbindung zeigt dieses (3,4,6)-Netzwerk keinerlei strukturelle Flexibilität während der Aktivierung, der Adsorption von verschiedenen Gasen sowie von Gastmolekülen aus der Flüssigphase. Man erhält ein starres Material mit einer spezifischen inneren Oberfläche (SSA) von 4670 m2g-1 und einem totalen Porenvolumen (VP) von 2.22 cm3g-1.
Aufbauend auf den positiven Ergebnissen der Copolymerisationsstrategie von DUT-25, wurde versucht, diese auf weitere kostengünstige Linkersysteme zur Synthese hochporöser MOF-Verbindungen auszuweiten. Durch eine effiziente und günstige Synthese einer Tricarbonsäure auf Amidbasis, 4,4´,4´´-[1,3,5-Benzentriyltris(carbonylimino)]trisbenzoesäure (H3btctb), und deren Kombination mit der linearen 4,4´-Biphenyldicarbonsäure (H2bpdc) und Zinknitrat wurde ein neues mesoporöses Koordinationspolymer DUT-32 (Zn4O(btctb)4/3(bpdc)) mit hierarchischem Porensystem erhalten. Dieses System konnte nur unter Zuhilfenahme von überkritischem CO2 in einen porösen lösungsmittelfreien Zustand überführt werden. Hierbei konnten die gravierenden Einflüsse verschiedener Parameter während der Trocknung (Lösungsmittel, Verweilzeit) auf die porösen Eigenschaften des resultierenden Materials aufgezeigt werden.
Der Austausch des Reaktionslösungsmittels gegen Ethanolabs. und anschließende überkritische Trocknung führte zu einem amorphen porösen Material mit einem Typ-IV-N2-Isothermenverlauf und einer daraus berechneten spezifischen Oberfläche von 840 m2g-1, einem Mikroporen- sowie einem totalen Porenvolumen von 0.36 bzw. 2.91 cm3g-1. Erfolgt die Trocknung aus einem Lösungsmittel mit möglichst geringen Wechselwirkungen mit dem Netzwerk (Aceton, Amylacetat), so zeigt das resultierende kristalline Material nach einer CO2-Austauschzeit von drei Tagen gänzlich andere texturelle Eigenschaften mit einem Typ-I-N2-Isothermenverlauf, einer spezifischen Oberfläche von 5080 m2g-1 sowie einem totalen Porenvolumen von 2.27 cm3g-1. Wird diese Verweil- und damit die Austauschzeit im flüssigen CO2 weiter auf sieben Tage erhöht, steigt auch die Qualität/Porosität des Materials und man erhält eine Verbindung mit der bislang höchsten beschriebenen spezifischen Oberfläche (SSA = 7192 m2g-1), extrem hohem spezifischen Porenvolumen (VP = 3.16 cm3g-1) und hervorragenden Eigenschaften für die Gasspeicherung.
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Apaydin, Elif. "Microfabrication Techniques for Printing on PDMS Elastomers for Antenna and Biomedical Applications." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253138931.
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Taravella, Cicely C. "Is Mattering what Matters: A Validation Study of the Meta-Valuing Measure of Flexible Valuing." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc30517/.
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Freely choosing a life direction, or flexible valuing, is a core component of acceptance and commitment therapy (ACT). Initial research suggests that valuing behavior may contribute to psychological well-being, but has been stymied by a lack of an efficient measure. The current study examined the psychometric characteristics of a new measure of flexible valuing, the Meta-Valuing Measure (MVM), in a sample of 532 undergraduates. Exploratory factors analysis revealed 3 orthogonal factors, Valuing (α = .94), Freedom from Values Conflict (α = .92), and Flexibility in Valuing (α = .73). The majority of expected relationships with other constructs were significant including those with measures of values, mindfulness, quality of life, experiential avoidance, and psychological distress.
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Kolbe, Felicitas, Simon Krause, Volodymyr Bon, Irena Senkovska, Stefan Kaskel, and Eike Brunner. "High Pressure In Situ ¹²⁹Xe NMR Spectroscopy:: Insights into Switching Mechanisms of Flexible Metal-Organic Frameworks Isoreticular to DUT-49." American Chemical Society, 2019. https://tud.qucosa.de/id/qucosa%3A72507.
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Flexible metal-organic frameworks (MOFs) are capable of changing their crystal structure as a function of external stimuli such as pressure, temperature, and type of adsorbed guest species. DUT-49 is the first MOF exhibiting structural transitions accompanied by the counterintuitive phenomenon of negative gas adsorption (NGA). Here, we present high pressure in situ ¹²⁹Xe NMR spectroscopic studies of a novel isoreticular MOF family based on DUT-49. These po-rous materials differ only in the length of their organic linkers causing changes in pore size and elasticity. The series encompasses both, purely microporous materials as well as materials with both, micropores and small mesopores. The chemical shift of adsorbed xenon depends on xenon-wall interactions and thus, on the pore size of the material. The xenon adsorption behavior of the different MOFs can be observed over the whole range of relative pressure. Chemical shift adsorption/desorption isotherms closely resembling the conventional, uptake-measurement based isotherms were obtained at 237 K where all materials are rigid. The comparable chemical environment for adsorbed xenon in these isoreticular MOFs allows establishing a correlation between the chemical shift at a relative pressure of p/p₀ = 1.0 and the mean pore diameter. Furthermore, the xenon adsorption behavior of the MOFs is studied also at 200 K. Here, struc-tural flexibility is found for DUT 50, a material with an even longer linker than the previously known DUT-49. Its structural transitions are monitored by ¹²⁹Xe NMR spectroscopy. This compound is the second known MOF showing the phenomenon of negative gas adsorption. Further increase in the linker length results in DUT-151, a material with interpenetrated network topology. In situ ¹²⁹Xe NMR spectroscopy proves that this material exhibits another type of flexibility compared to DUT-49 and DUT-50. Further surprising observations are made for DUT-46. Volumetric xenon adsorption measurements show that this non-flexible microporous material does not exhibit any hysteresis. In contrast, in situ ¹²⁹Xe NMR spectroscopically detected xenon chemical shift isotherms exhibit a hysteresis even after longer equilibration times than in the volumetric experiments. This indicates kinetically hindered re-distribution processes and long-lived metastable states of adsorbed xenon within the MOF persisting at the time scale of hours or longer.
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Seehamart, Kompichit. "Investigation of the diffusion mechanisms of several hydrocarbons in the Metal-Organic-Framework Zn(tbip)." Doctoral thesis, 2010. https://ul.qucosa.de/id/qucosa%3A11169.
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Most of the computer simulations of molecules in Metal-Organic Frameworks (MOFs) to be found in the literature are done with rigid framework. But, Molecular Dynamics (MD) simulations of the self-diffusivity, Ds, of ethane within the one-dimensional 4.5 Å channels of the MOF type Zn(tbip)(H2 tbip = 5-tert-butyl isophthalic acid) presented in this work have shown not only quantitative, but also qualitative, differences in the Ds values for fixed and flexible lattices. Particularly, the dependence of Ds upon the concentration of molecules, c, is strongly influenced by the lattice flexibility. The reasons for this influence are investigated with the aid of probability density plots, free energy landscapes and barriers, along with a determination of the structural changes accompanying increasing c. It is found that for flexible lattices, the tighter, more constrained parts of the channels become wider at higher c; this allows more molecules to diffuse in the central region of the channels.
The investigations for Zn(tbip) have been extended to three equimolar mixtures of ethane/ethane, CO2/ethane and CO2/methanol. The simulations take into account the lattice flexibility. The diffusional characteristics are discussed in relation to molecule properties and lattice geometry. The results show that Zn(tbip) may be a useful material for separating methane/ethane and CO2/ethane mixtures at low concentrations, and CO2/methanol mixtures at high concentrations.
The temperature and concentration dependence of the self-diffusivity of propane diffusion in Zn(tbip) have been investigated as well by performing normal MD and hyper-MD with bias potential simulations. The obtained temperature dependence of the self-diffusivities is analyzed using an Arrhenius relationship, yielding the activation energy to be 9.53 kJ/mol and the pre-exponential factor to be 4.48×10-9 m2s-1. Using this hyper-MD method, interesting mechanisms of the propane molecules able to pass each other and exchange their sites in the channels can be observed. Because of mutual hindrance of propane molecules, the propane self-diffusivities decrease with increasing concentration.
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Chen, Chen-Chun, and 陳貞君. "Metal Foil Flexible Organic Solar Cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/90802531830929521931.
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Yeh, Yi-Ting, and 葉奕廷. "Implantable Flexible Complementary Metal Oxide Semiconductor Fabrication Technology." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/17723578454288481539.
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碩士國立清華大學
奈米工程與微系統研究所
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Recently the techniques of applying microtransducers on the biomedical microsystems, such as Cochlear and artificial retina, have become more and more noticeable and well-developed. Yet the fabrication process of transforming the microtransducers into biocompatible flexible devices has not been well-studied. Therefore, we developed a fabrication technique that could generally apply to various of microtransducers. In this research, a novel fabrication process for making biocompatible flexible integrated circuits is presented. By utilizing lapping, etched, deposition Parylene C, we are able to transform electronic devices and microtransducers into flexible and biocompatible devices. In this work, CMOS transistors were fabricated using 0.18 μm technology on an 8-inch SOI (silicon on insulator) wafer。By the wafer back grinding technique and the repeated Parylene C deposition, we constructed 30μm-thick flexible sandwich structure of CMOS transducers from the original thickness of 700 μm. The implantable flexible CMOS transducers are then measured by a Semiconductor Parameter Analyzer HP4156C. The characteristic curves and threshold voltages are shown to have mere small variation before and after this fabrication technique.