Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 80 for “"chemical bonds"”.
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New perspectives in IQA: from biochemical applications to controversial chemical bonds
Desde su surgimiento unos quince años atrás, el método de descomposición de la energía de átomos cuánticos interaccionantes (IQA) ha demostrado ser un útil descriptor del enlace químico. Sin embargo, la aplicación de dicho método libre de referencias e invariante orbital se ha visto fuertemente …
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CHEMICAL BIOLOGY STRATEGIES FOR THE FORMATION AND CLEAVAGE OF CHEMICAL BONDS
… and better understanding of how specific chemical bonds can be either formed or broken gives chemical biologists opportunities to control and regulate these processes with high precision. Therefore, with growing importance of the field of chemical biology, expansion of the toolbox of …
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Corporate bodies and chemical bonds : an STS analysis of natural gas development in the United States
… into subsurface shale formations of synthetic chemical mixtures, has been viewed by the natural gas industry as a practice of great promise. But there is another side to the story. The first half of this dissertation explores an innovative scientific approach to studying the possible …
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Theoretical and computational investigations of the electron and spin correlation in chemical bonds, building a predictive bonding model with generalized valence bond theory
… quantum chemistry is to understand the nature of chemical bonds. By understanding the underlying physical and chemical principles of chemical bonding in various molecules, chemists can make predictions about the structures, energetics, reactivities and other properties of chemical species. The …
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Exploring Strategies to Break Adsorption-Energy Scaling Relations in Catalytic CO Oxidation
An atomistic control of chemical bonds formation and cleavage holds the key to making molecular transformations more energy efficient and product selective. However, inherent scaling relations among binding strengths of adsorbates on various catalytic materials often give rise to volcano-shaped …
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Advances in the Synthesis and Application of Dynamic Covalent Polymer Networks
… of plastic materials. Thermosets have excellent chemical stability, strength, and durability but cannot be recycled. On the other hand, thermoplastics are recyclable, but this comes at the cost of lower stability, strength, and durability. In this dissertation, we aim to combine the advantages of …
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Towards Sustainable Electrosynthesis of Industrially Valuable Small Molecules
… as a means of making and breaking arbitrary chemical bonds. The development of such carbon-neutral systems demands the design of efficient and selective electrocatalysts with an eye towards economic viability and industrial operability. In this work, we present three electrochemical processes …
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Fabrication of nanostructures with the scanning tunneling microscope and the laser
… (STM). Laser radiation is used to break the chemical bonds of gas-phase trimethylaluminum molecules to free aluminum atoms in the region of the tunneling gap of the STM. The atoms are subsequently selectively excited and ionized. The ions are then driven softly toward the surface where they …
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Ab-initio and thermodynamic study of 123I-MIBG and 76Br-MBBG : choosing an effective tracer and theoretical study of the binding mechanism of 1-allyl 2-Thiourea as a functional monomer of Methyl Nitrate template
… reaction energetics, and thermochemistry of chemical reactions is possible computationally. This is because computational methods are well able to help understand and also describe the dynamics of chemical bonding -- forming and breaking of chemical bonds. Hence, it becomes very important to …
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Production of Ethanol from Cereal Food Fines using Dilute-Acid Hydrolysis
… to the feedstock to facilitate the breaking of chemical bonds. This study investigates the effect of different concentrations of acid to determine optimal conditions for the production of ethanol. It was found that higher concentrations of acid yielded greater production of ethanol and, overall, …
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Metal-support interactions on Fe-based Fischer-Tropsch catalysts
… it is proposed that the development of chemical bonds at the interface between the active metal and the support material is responsible for the altered catalytic behavior in supported catalysts [Qing et al., 2011; Sou et al., 2012]. The presence of these bonds is believed to alter the …
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Accurate charge densities of amino acids and peptides by the Maximum Entropy Method
… by the Maximum Entropy Method (MEM) to study chemical bonds. The MEM model-independently determines the most probable electron density, which simultaneously maximizes the information entropy and fits the X-ray diffraction data. The quality of the MEM densities is enhanced by several extensions …
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Photophysics and optoelectronics of metal halide perovskites and other unconventional semiconductors
… which is determined by the nature of the chemical bonds. Additionally, the power conversion efficiencies, when we speak of panels, are still far from their theoretical limit. To further advance towards the technological application of metal halide perovskites more work is needed, spacing …
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Produção, caracterização e avaliação in vitro de filmes finos de vidro niobo-fosfato por deposição a laser pulsado
… surface’s ability to create strong and direct chemical bonds with adjacent bone tissue. Surface treatments are a way to obtain these surface properties. Among the different treatments, bioactive materials coatings stand out. In this work, thin niobo-phosphate bioactive glass …
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Pairing and entanglement: quantum Monte Carlo studies
… step reveals a novel way of understanding chemical bonds, as exemplified by Be2 and C2 . Possible implications of these results in integrable many-body models and in quantum chemistry are discussed, as well as direction for future investigation.
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Advances in Multiconfiguration Pair Density Functional Theory and Applications to Excited State, Singlet-Triplet Gaps and Magnetism
… spectra, magnetism, characterization of chemical bonds, catalysis etc. It is therefore important to be able to correctly describe the interactions between electrons, also known as electron correlation, whose description is a major challenge for modern electronic structure methods. The …
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A Study of the Mechanism of Phenol and Amine thiols as Antifatigue Agents by ESR
… have been carried out on the nature of the chemical bonds in cross-linked rubber that break under the influence of mechanical stress, and on the way in which a commercial antifatigue agent, 4-iso-propy1-4-pheny1--p-phenylenediamine (IPPD), inhibits the mechanodegradation of natural rubber …
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Controlling molecules with lasers and lasers with molecules
… Interesting pulse shapes have been able to break chemical bonds, drive chemical reactions, selectively excite molecular states, and most recently, control photoisomerization in proteins [1, 2, 3]. In this thesis I began by seeking to apply this technique to manipulate spin. In our early work we …
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Through adhesive surface treatment for bonded joints
… pretreatments, there is potential for novel chemical reactions between adhesives and adherends. It may be proposed that, in the absence of a coherent oxide layer, an adhesive will form primary chemical bonds to a reactive metal adherend. Primary bonds may endow an adhesive to adherend …
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Rotational spectra and molecular structures of organometallic and organic molecules
Understanding the nature of chemical bonds constitutes a major theme of this thesis. This thesis investigates the gas phase rotational spectra, electronic charge distributions and molecular structures of organometallic and organic molecules, using high-resolution pulsed beam Fourier transform …
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