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 107 for “"thin layers"”.
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Induced Phase Transition in Magnetoelectric BiFeO3 Crystals, Thin-layers and Ceramics
… effects. Variously oriented BiFeO₃ epitaxial thin films have been deposited by pulsed laser deposition. Dramatically enhanced polarization has been found for (001)c, (110)c, and (111)c films, relative to that of BiFeO₃ crystals. The easy axis of spontaneous polarization lies close to (111)c …
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Design of Phonon Polariton Propagation in Thin Layers of Highly Anisotropic Materials
La nanoóptica es un campo de investigación que estudia las interacciones luz-materia a escala nanométrica. Uno de sus objetivos clave es, por tanto, comprimir la luz en volúmenes mucho más pequeños de los que ocupa en el espacio libre, lo que se logra reduciendo considerablemente su longitud de …
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Mediated Patterning of Sol -Gel Thin Layers: Shrinkage, Decohesion, and Lift-Off
The shrinkage and densification of sol-gel layers were determined by in-situ and ex-situ measurements, where a ∼30% decrease in thickness (t) was typical during drying of sol-gel layers (T < 300°C). Constrained shrinkage, resulting from adhesion to the supporting silicon substrate, led to a …
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Chemical evolution, heteroepitaxy, and monolayer patterning of solution-derived lithium niobate thin layers
Integrated lithium niobate (LiNbO$\sb3$) thin films are of technical interest for frequency doubling and a variety of efficient photonic circuit element applications. Solution deposition of such films on near lattice-matched substrates has been conducted, allowing low temperature processing, …
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Optical Characterization of chemically doped and/or intercalated thin layers graphene: Raman and Contrast Study
… change in chemically doped and/or intercalated thin layers of graphene with halogen gases, FeCl₃ and alkali metals. The first chapter introduces graphene and graphite intercalation compounds (GICs). It will also briefly explain Raman of the graphitic compounds including GICs. The second chapter …
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Phase development and texture for lead-based perovskite thin layers prepared by sol-gel processing
… for sol-gel derived lead-based perovskite thin layers. Dielectric and ferroelectric properties were examined in terms of crystal structure, microstructure, and preferred orientation. Ferroelectric La-modified Pb(Zr,Ti)O$\sb3$ (PLZT) and antiferroelectric PbZrO$\sb3$ (PZ) were chosen as …
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Evolution of local structure and stress development during thermal treatment of sol-gel-derived PZT-based thin layers
… recent years on the deposition of ferroelectric thin layers by sol-gel processing. However, to sustain further improvements in the technique necessary for widespread applications, a systematic approach to the study of physical, chemical and structural changes that occur during transformation from …
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Thermal processing and the evolution of composition, structure and properties for sol-gel derived lead zirconate titanate thin layers
… $\rm Pb(Zr\sb{0.53}Ti\sb{0.47})O\sb3$ (PZT) thin layers. Emphasis was placed on the effect of thermal processing conditions on the gel-to-ceramic conversion. In addition, the effects of interfacial reactions, and residual stresses on the measured properties were also considered. The purpose …
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Evolution of molecular structure during the sol-gel processing of lithium niobate and the development of microstructure in alkoxide-derived thin layers
Lithium niobate powders and thin-layers were prepared by sol-gel processing. Lithium niobium ethoxide and lithium niobium methoxyethoxide bimetallic alkoxides were used for both gel and thin-layer formation. Advantages of sol-gel processing were demonstrated by synthesis of …
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Seismic data decomposition using sparse dictionary
… used to quantitatively predict the thickness of thin layers. The current popular time-spectrum analysis methods include the Short Time Fourier transform (STFT), Continuous Wavelet Transform (CWT), S-transform (ST), and Matching Pursuit (MP), among which MP is the most tolerant of window/scalar …
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Sol-gel processing, perovskite phase development and properties of relaxor-based thin layer ferroelectrics
… reports on the preparation and properties of thin layer ceramics in the Pb ((Zn$\sb{1/3}$Nb$\sb{2/3})\sb{\rm 1-x}$Ti$\sb{\rm x}$) O$\sb3$ (PZNT) and Pb ((Mg$\sb{1/3}$Nb$\sb{2/3})\sb{\rm 1-x}$Ti$\sb{\rm x}$) O$\sb3$ (PMNT) systems for capacitor and ferroelectric applications. Sol-gel methods …
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A chemical study of the silicate minerals of the Great Gossen Lead and surrounding rocks in southwestern Virginia
… gneisses predominate. Other lithologies include thin layers of hornblende amphibolite, sulfide ore, quartz veins, thin layers of hornblendic gneiss, marble lenses and minor solution cavities. The coarser-grained ore zone lithologies are dominated by chlorite, hornblende and actinolite-tremolite …
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Electrostatic force balance microscopy
… microcantilever to electrically stimulate thin layers of doped semiconductors, locally depleting the layer to create a “virtual aperture” while simultaneously sensing the electrostatic force exerted on the tip by the electric potential of the conductors buried in the oxide. The operating …
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LIDAR Studies of the Middle Atmosphere Temperatures and Iron Layer at South Pole
… to the background level, resulting in extremely thin layers and very low abundances during summer. The bottom sides of the Fe and Na layers are governed by different temperature-dependent neutral chemistry. The Fe density is correlated more closely with the temperature than is the Na. Above 95 …
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Metalorganic Chemical Vapor Deposition and Its Application to the Growth of the Heterostructure Hot Electron Diode
… high-quality compound semiconductors in thick or thin layers with abrupt junctions, excellent area uniformity, and precisely controlled thickness, doping and composition. In this work the desired characteristics of an MOCVD system are described, and design criteria necessary for their …
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Anisotropic wave guides-- propagation, focusing and dispersive phenomena with applications for non-destructive testing.
… of manufactured and raw materials consist of thin layers. Some examples include rolled aluminum, window glass, plywood, automobile bodies, plane wings, silicon wafers, bridge support beams, and paper. These layers can be viewed and modeled as acoustic waveguides. This thesis will present the …
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Ion Beam Mixing of Metal/Fluoropolymer Interfaces
… the "mixing' effect of 50 keV nitrogen implanted thin metal layers on Teflon PTFE (polytetrafluoroethylene). RBS analysis shows that thin layers copper and chromium approximately 300-400 Å thick become distributed though the implant layer of the Teflon. When the implant fluence increases the …
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Graphene-Assisted gan membranes formation /
… This material was composed of polyimide plastic layers. While this engineering breakthrough is fascinating, certain applications require higher carrier mobilities and physical properties that do not degrade under harsh environmental conditions. Consequently, inorganic optoelectronics emerges as a …
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Study of the aldopentoses and fucose in human urine by thin-layer chromatography
… analytical procedures based on one - dimensional thin-layer chromatography have been devised whereby it has become possible for the first time rapidly (3 h) to separate and measure at microgram levels, arabinose, ribose, xylose and fucose from the numerous other sugars present in urine from human …
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Axiomatic development of a machine control system
… and the intelligent control of them to planarize thin layers of wafers. Signal processing modules, control algorithms, sequential process steps, graphical user interface, process recipe editor and the overall control system structure are all designed by the Axiomatic decomposition. Axiomatic …
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