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 21 for “"Chemical state"”.
-
Deposition of Metal Oxides and Metal Carbonyls on Silicon Surfaces Using Solution Chemistry
… spectroscopy analysis furnished the chemical state of the adsorbates as well as quantitative information. Static secondary ion mass spectrometry analysis detected the presence of the desired product and trace amounts of byproducts on the surface. Finally, numerical simulations of …
-
Multivalent Random Walkers:A computational model of superdiffusive transport at the nanoscale
… bind to and irreversibly modify surface-bound chemical substrate sites arranged as nanoscale tracks. As the legs attach to, modify, and detach from the sites, the walker moves along these tracks. Walkers are symmetrical and the tracks they walk on are unoriented, yet we show that under …
-
Surface-mediated mechanisms for defect engineering in zinc oxide
… zinc oxide: near-surface electrostatics and the chemical state of surface active sites.
-
Synthesis of functionalized few layer graphene via electrochemical expansion
… and intriguing electrical, mechanical, and chemical properties. However, mass production of high-quality, solution-processable graphene via a simple low-cost method remains a major challenge. Recently, electrochemical exfoliation of graphite has attracted attention as an easy, fast, and …
-
The role of hydrogen in the growth of carbon nanotubes : a study of the catalyst state and morphology
The role of hydrogen in chemical vapor decomposition (CVD) of C2H4 for growth of carbon nanotubes (CNTs) was investigated. Fe/A1203 (1/10 nm) catalyst layers were used for growth on Si substrates and the times at which H2 was introduced during the 40 minute temperature ramp, 15 minute annealing …
-
High temperature investigations of crystalline silicon solar cell materials
… This technique allows for mapping and chemical state determination of metal impurity clusters on the order of 100 nm to 100 [mu]m, over sample areas of several square millimeters, at temperatures in excess of 1200°C and under controlled ambient atmosphere. The application of this …
-
Improved catalysts with properties controlled by semiconductor band engineering
… even as Pt remains constant at its Pt0 chemical state.
-
Concentration depth-profile reconstruction from angle-resolved XPS data using the maximum entropy method: characterization of surface film formed on Ni-18P alloy
… from ARXPS data. Combining information on the chemical state of the different phosphorus compounds in the layered interface with the reconstructed in-depth profile it can be concluded that the high corrosion and wear resistance of Ni-P alloys is due to a thin, self-repairing …
-
Evaluation of plasma sprayed coatings as surface pretreatments for adhesive bonding
… spraying techniques may offer an appropriate non-chemical-solution method to prepare metal surfaces for adhesive bonding. The technique has the capability of coating an adherend with almost any chemical compound. Plasma spraying techniques allow for optimization of coating characteristics such as …
-
Chemistry Of Antiwear Films By X-ray Absorption Spectroscopy
… films is likely from sulphur in base oil.;The chemical composition of additives also affects their behaviour. Secondary ZDDP tends to form long chain polyphosphate while primary ZDDP and aryl ZDDP, in most of the cases, form short chain polyphosphate. The chemical state of sulphur in the same …
-
Fundamentals and new applications of electrochemical promotion in catalysis
Electrochemical promotion (EP) is a new way of controlling catalytic performance. It is implemented by depositing porous thin film metal catalysts on solid electrolyte supports where they act as both a catalyst and a working electrode of an electrochemical cell. The technique entails …
-
X-RAY CHARACTERIZATION OF PLATINUM GROUP METAL CATALYSTS
… spectroscopy provides information about the chemical state and local structure of selected atoms. From the average nearest neighbor coordination numbers, crystallite sizes can also be inferred, with particularly high sensitivity in the sub-nm size range. Electron microscopy complements …
-
Biomedical applications of nanostructured polymer films
… to determine the atomic composition and chemical state of polymeric thin films with <10nm nanometer depth resolution without any chemical labeling or modification. Using this technique, I probed the nanostructure of functional thin films to quantify the interlayer diffusion of the …
-
Science of single-wall carbon nanotubes: Purification, characterization and chemistry
… that the roping occurs without changing the chemical state of the nanotubes. Acid intercalation of single wall carbon nanotubes is examined. Several super acids and strong acids are used to study the charge transfer and protonation effects on SWNTs. The degree of charge transfer is clearly …
-
The Early Evolution of Terrestrial Planets: Impact Simulations and Planetary Chemistry
… pathways available to that world. The chemically reduced metallic iron cores of these large impactors are key to such processes, as are the vast sums of energy that such impacts deliver. In this thesis, we explore the environments of such scenarios in the aftermath of impacts, modelling …
-
Hard x-ray microanalysis with parabolic refractive lenses
… scanning microscopy allows to examine the chemical state and the local environment of a given atomic species in a virtual slice through a sample without really cutting it. The demand for X-ray microprobes with still smaller spot size is growing. For this reason nanofocusing refractive …
-
Corrosion and Tribocorrosion Kinetics of Al-based Concentrated Alloys in Aqueous Sodium Chloride Solution
… coefficient of friction and real contact area. Chemical wear tended to increase with scratching frequency, most likely due to faster repassivation kinetics at lower frequency. The surface layer was analyzed by cross-sectional transmission electron microscopy, indicating the passive film was …
-
The creation and use of a chemical kinetics code to model and understand the atmospheres of hot Jupiters
Chemical compositions of exoplanets can provide key insights into their physical processes, and formation and evolutionary histories. Atmospheric spectroscopy provides a direct avenue to probe exoplanetary compositions. However, whether obtained in transit or thermal emission, spectroscopic …
-
Study of Chemical States, Composition and Adsorption Behavior of Iron Coated Granular Activated Carbon (Fe-GAC) for Selenate Removal and Feasible Adsorbent Modifications
… the type of surface complex and the coordination state of adsorbed selenate at different pH with 0.1 M ionic strength. The results showed that inner-sphere and outer-sphere complexes were formed at pH 5 and 8, respectively. Additionally, mixture of mono-dentate and bi-dentate binding was observed …
-
The Fate and Effects of Contaminants in Estuarine Environments
… “Ecohardness”, reflecting the estuarine chemical budget by the analysis of the material strength of cockle shell. From this research, lead, cadmium and zinc were found to be the most concerning polluting elements in the study location, with levels above sedimentary ANZECC safety …
Page 1 of 2