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.
Results
Showing 1 to 20 of 34 for “"chemical bond"”.
-
Interdependence between geometric, tensile and chemical bond behaviours of untreated hair fibres
… between fibre curliness, strength and chemical bonding. In the current understanding of hair mechanics, curly fibres are considered to have a lower tensile strength than straight fibres. Furthermore, the current understanding of hair fibres does not associate hydrogen bonding with fibre …
-
The Physico-chemical Nature of the Chemical Bond: Valence Bonding and the Path of Physico-chemical Emergence
Through the development of physical chemistry and chemical physics over the late-nineteenth and early-twentieth centuries, the relationship between physics and chemistry changed to create a broad interdisciplinary framework in which chemists and physicists could make contributions to problems of …
-
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 …
-
Exploring kinetics and thermodynamics in fast-ion conductors and hydrogen-storage materials using ab-initio molecular dynamics
… mobility upon melting. We also find a unique chemical signature for the fourth nearest-neighbor silver to an iodine. This fourth silver is weakly bound and relatively unconstrained, and we isolate it as the predominant agent in the diffusion process. Next, a detailed statistical analysis is …
-
ORGANOMETALLIC CHEMISTRY FROM THE INTERACTING QUANTUM ATOM APPROACH
… which provide a complete description of the chemical bond in terms of electron density. In order to make benchmark of this new technique classic metal-organic molecules like metal carbonyls, metal hydrides and simple metal dimeric compounds were studied.
-
Some studies of the reaction between stannic chloride and silver perchlorate in anhydrous media
The theory of the chemical bond, particularly in compounds where the bonds are neither purely electrovalent nor purely covalent, has in recent years received a great deal of attention. Of the oxy-acids which can form ionic as well as covalent compounds, perchloric acid and sulphuric acid are of …
-
The mechanochemical modification of polyolefins using reactive modifier systems
… polypropylene (PP) composites by the mechanochemical modification of the PP. The modification of the PP was carried out by reactive processing of the PP with a modifier in a Buss Ko-Kneader. Two main types of modifier were evaluated one type based on N-substituted maleimides the others based …
-
Photolysis of fluorinated organic molecules: fluorine mass balances and the roles of nucleophiles, rings, and degree of fluorination
… accumulation within the environment. When these chemicals are exposed to environmental conditions, abiotic degradation pathways such as photolysis may occur. Photolysis results from photon absorption by a chromophore on the molecule. Following photon absorption, chemical bond breakage, …
-
A multireference coupled-cluster method using a single-reference formalism.
… dissociation of some model systems with a single bond (LiH and Li₂) are calculated using CC doubles (CCD), singles and doubles (CCSD), singles, doubles and triples (CCSDT) and CCSDTQ. These calculations demonstrate the magnitude of the CC contributions arising from triple and quadruple excitation …
-
Application of Preformed Metal Crowns on Class II Carious Lesions on Primary Molars /// Приложение на преформирани метални коронки при втори клас кариозни лезии на временни молари
… potential) to hard tooth tissues, provide chemical bond with the tooth’s structures. Thus these materials do not require any additional retentions in the prepared cavities which preserve the healthy dental structures. In addition, they are quite tolerant to moisture. One of the main …
-
Pushing the Limits of the Lithium Indicator Carbon Acidity Scale Using Cyclopentadiene Chemistry and 19F NMR Spectrometry
C-H bonds are easily the most common type of ordinary chemical bond and studying carbon acidity will help us understand and predict the reactivity of organic compounds. Carbon acidities are ranked using acidity scales. One of the most prominent is the Streitwieser Lithium Indicator (SLI) scale. The …
-
Design and Modular Optimization of Components in Molecular Solar Thermal (MOST) Systems
… of capturing solar energy and storing it as chemical bond strain energy. The work specifically addresses the challenges associated with the norbornadiene/quadricyclane (NBD/QC) couple, focusing on the optimization of the back-conversion reaction through heterogeneous catalysis and the …
-
Homodyne High-harmonic Spectroscopy: Coherent Imaging of a Unimolecular Chemical Reaction
… generation to probe femtosecond (femto=10^-15) chemical dynamics for the first time. Thanks to the coherence imposed by the strong driving laser field, homodyne detection of attosecond pulses from excited molecules undergoing dynamics is achieved, the signal from unexcited molecules acting as …
-
Phononic metamaterials based on complex geometries : "a new kind of metamaterial"
… with greater freedom (i.e. not limited by the chemical bond or ionic bond in classical materials system). We studied metamaterials using prefractals from both exact-self similar fractal and random fractal samples. For exact-self similar fractals, we choose H tree based prefractals and Hilbert …
-
Synthesis of self-assembled polystyrene nanospheres/cadmium metal nanoparticles (PSNs/CdMNPs) composite thin film for its application as adsorbent and catalyst
… the secondary pores structural and physicochemical properties of polystyrene nanospheres/cadmium metal nanoparticles (PSNs/CdMNPs) composite thin film with its adsorption and catalytic properties. The PSNs/CdMNPs composites were fabricated on a hydrophilic silicon wafer through …
-
Low dielectric constant fluorocarbon films containing silicon by plasma enhanced chemical vapor deposition
… The films were prepared by plasma enhanced chemical vapor deposition (PECVD) using gas precursors of tetrafluoromethane as the source of active species and disilane (5 % by volume in helium) as both an active species source and a reducing agent to control the ratio of fluorine to carbon in …
-
Quantum Mechanical Study of Spin-Forbidden Reactions in Organometallic Catalysis and Astrochemistry
… spin-forbidden reactions in organometallic C-H bond activation and interstellar peptide-bond formation, as well as the derivation of the Morse empirical potential from an electrostatic model. In the first part, the role of triplet electronic state in spin-accelerated iron-catalyzed C(sp2)-H bond …
-
Crystal structure, electron density and chemical bonding in inorganic compounds studied by the Electric Field Gradient
… of the EFG can provide valuable insight into the chemical bonding. Whereas the experimental determination of the quadrupole frequency and the closely related EFG has been possible for more than 70 years, reliable values for calculated EFGs could not be obtained before 1985, when an EFG module was …
-
Following a Photochemical Reaction of Br2 using Photoion and Photoelectron Momentum Spectroscopy
When a chemical bond is breaking, the valence electrons within the bond undergo rearrangement, causing a corresponding rearrangement and separation of the atoms within a molecule. This process couples the motion of valence electrons and atoms, making it essential to concurrently visualize both in …
-
An experimental determination of the homogeneous nucleation rate of water vapor in argon and helium
… heterogeneous nucleation appears to occur upon chemically bonded centers whose concentration is very low and depends upon the vapor pressure before the expansion. The consistency of the number of the nucleating centers indicates that they may be a neutral product of the action of natural …
Page 1 of 2