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Dissertations / Theses on the topic 'Nano'
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Stehr, Joachim. "Nano-Heizplatten." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-124531.
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Garrett, Natalie. "Nano-biophotonics." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/119846.
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Photonic techniques are the methods of choice for probing biological systems, as they are non-invasive, non-ionising, inexpensive, and are ubiquitous. When applied to the treatment and prevention of disease and for pathology in general, biophotonics offers a means to bridge the gap between understanding of molecular structures and their role in physiological functions. There is a wide range of such techniques used in imaging, assaying, bio-sensing, optical diagnosis, each of which has limitations as well as benefits. The experiments outlined in this thesis use nanotechnology to overcome the limitations of resolution, contrast and chemical specificity with photonic techniques in biology. The experimental work outlined in this thesis is divided over three chapters, the first of which is concerned with nanostructured metallic surfaces for use in surface enhanced Raman scattering (SERS) for protein assay applications. This chapter gives details of the methods used to produce and characterise SERS substrates using gold and silver thermally evaporated onto butterfly wing sections, together with the protocols developed for manufacturing biomimetic analogues of these naturally occurring nanostructures. The conjugation system designed to modify the metal surfaces for use in an avidin/biotin model protein binding assay is described, together with an account of the efficacy of the final assay. The results obtained show that such naturally occurring nanostructures, and their biomimetic analogues, are suitable for use as SERS substrates for wet protein binding assays. This work represents a major advance in the field of SERS assay. The experimental chapters describe experiments that use coherent Raman scattering (CRS) methods to probe the interactions between nanoparticles and live cell cultures, as well as provide chemically selective images of tissue samples.
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Ivry, Yachin. "Nano ferroelectrics." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609375.
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Fernandini, Vargas Gino Roberto, Quiñonez Christian Fronda, Rojas Marilú Lévano, and Samanez José Alonso Taco. "Nano Shield." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2017. http://hdl.handle.net/10757/624151.
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Importación de productos Nano X del país de México y en su posterior distribución en el territorio peruano. Los temas abordados están organizados de manera secuencial en capítulos que cubren los siguientes temas: Aspectos generales del negocio, planeamiento estratégico, investigación y validación del mercado, plan de marketing, plan de operaciones, estructura organizacional y de recursos humanos y finalmente el plan económico financiero. Los productos Nano X son recubrimientos nano-tecnológicos para vehículos, los cuales ofrecen protección hasta por un año contra el polvo, la lluvia, el sol, etc. En el caso de los interiores también ofrecen protección contra derrames de líquidos. Los ingresos provienen de la venta directa de los productos. Para ello, nos centraremos en empresas importadoras de vehículos, almacenes logísticos especializados y demás empresas que cuenten con flotas de vehículos como es el caso de empresas de transporte, organismos gubernamentales, empresas contratistas, entre otras.<br>Import of Nano X products from the country of Mexico and its subsequent distribution in the Peruvian territory. The topics addressed are sequentially organized into chapters that cover the following topics: General aspects of the business, strategic planning, research and market validation, marketing plan, operations plan, organizational structure and human resources and finally the financial economic plan. Nano X products are nano-technological coatings for vehicles, which offer protection for up to 1 year against dust, rain, sun, etc. In the case of interiors, they also offer protection against liquid spills. The income comes from the direct sale of the products. For this, we will focus on vehicle import companies, specialized logistics warehouses and other companies that have vehicle fleets such as transport companies, government agencies, contractors, among others.<br>Trabajo de investigación
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Orhan, Tugba. "Nano Structural Metal Nano Composites: Synthesis, Structural And Thermal Characterization." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610799/index.pdf.
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Recently, the use of block copolymers in preparation of nanocomposites has received great attention as they form well-defined micelles. In this work, the synthesis of different metal functional copolymers, nano structural metal composites and investigation of their reaction mechanism and thermal characteristics by pyrolysis mass spectroscopy have been aimed. Namely, polyisoprene-block-poly2vinylpyridine, (PI-b-P2VP) and poly2vinylpyridine-block-polymetylmethacrylate, (PMMA-b-P2VP) were used as block copolymers and the thermal reaction of these copolymers with two different transition metal complexes Cr(CO)6 and HAuCl4.3H2O were investigated which mostly lead to the coordination of metal through nitrogen atom of the pyridine ring which then degrates to form nano particles. The samples were further characterized by TEM, ATR-FT-IR, UV-Vis and Direct-Pyrolysis Mass Spectroscopy techniques.
TEM images proved the formation of nanoparticles and the results showed that synthesized Au nanoparticles have 2 to 3 fold larger size than Cr nanoparticles. ATR-FT-IR spectrum of metal functional copolymers showed that the disappearance of characteristic peaks of pyridine stretching and bending mode when metal coordinates to the pyridine nitrogen. Furthermore, the spectrum indicated the appearance of a new absorption peak at around 740 cm-1 which may be a clue for the coordination of gold(III) ion to the pyridine nitrogen. Different from chromium case, in the spectrum of Au3+-(PMMA-b-P2VP), CO stretching frequency of PMMA which may appear at around 1720&ndash<br>1718 cm-1 decreased in intensity while a new absorption peak appeared at around 1600 cm-1. This results reveals that electron deficient gold (III) ion prefers the coordination from both donor atoms namely carbonyl oxygen PMMA and pyridine nitrogen of P2VP in order to compensate its electron deficiency. In the UV-Vis spectrum of copolymers, Cr-functional copolymers showed a sharp absorption peak appeared at around 290 nm is attributed to a MLCT transition from chromium atom to * orbital of pyridine group. Furthermore, Au-functional copolymers showed a completely new absorption band at around 320 nm which can be associated again with a LMCT transition since gold is electron deficient and more willing to accept electrons from the ligand. Pyrolysis mass spectrometry analysis showed that poly2vinylpyridine blocks for each copolymers were affected similarly but polyisoprene block was not affected much from the coordination of metal compared to poly(methyl methacrylate) block in copolymers. For (PI-b-P2VP), Au3+ coordination to copolymer resulted in the higher thermal stability compared to Cr coordination. For (PMMA-b-P2VP), different from Cr, Au3+ coordination to P2VP nitrogen atom was extensive and
PMMA based products changed drastically due to the coordination of electron deficient Au3+ to PMMA carbonyl group.
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Samouhos, Stephen V. (Stephen Vincent) 1982. "Nano-materials for novel magneto-rheological liquids and nano-fluids." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40889.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.<br>Includes bibliographical references (p. 56-60).<br>Introduction: Nanotechnology, in its many forms, has evolved as a forefront of the global scientific and technological frontier. Materials once disregarded as very small dust or particulate impurities twenty years ago, are today, the focus of intensely popularized investigation. New materials have been synthesized via nanometer precision engineering, and their resulting properties continue to defy the thermal, electrical, and mechanical limitations of conventional materials [1]. Even liquid suspensions of nano-particles yield tremendous enhancements in thermal and transport rates that still remain unexplained. Analogously, forty years ago the machining and synthesis of object features with nanometer dimensions and accuracy was a mere scientific interest. Today, that capability forms the core technical competency of the leading manufacturers of micro-processor electronics. The purpose of this thesis is to contribute to the field of nanotechnology through the synthesis of a novel nano-material, and to examine its utility in areas such as directed self-assembly and nanofluid enhanced mass transport.<br>by Stephen V. Samouhos.<br>S.M.
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Eder, Katja Daniela. "Surfaces and interfaces in nano-scale and nano-structured materials." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17217.
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In this thesis, advanced characterisation methods, including atom probe tomography (APT) and transmission Kikuchi diffraction (TKD) were employed to study surface and interfaces in a range of nano-scale and nano-structured materials. These techniques were used to measure solute segregation towards grain boundaries and to explore the relationship between grain boundary segregation and grain boundary mobility. APT was also used to characterise the structure of nanoparticles used as catalysts, and the adsorption behaviour of sulphur on catalytic surfaces, to gain more information about the structure-activity relationships, and deactivation processes. This research included the development and improvement of new and existing APT sample preparation techniques, conducting the experiments, and data analysis. The first part of this thesis is concerned with nanocrystalline alloys processed by severe plastic deformation. In the second part the exceptional hardening of an 316L austenitic steel during annealing was also investigated using APT. This thesis also concentrated on the study of nanoparticles for catalysis via APT. Systematic investigations of different APT sample preparation techniques were performed in order to find a way of producing reproducible and reliable specimens. Different acquisition parameters, substrates and coatings were tested to improve the APT data quality. Experiments were conducted in which needles were dipped in thiophene. Here the aim was to investigate the phenomenon of sulphur poisoning by using APT to investigate how thiophene bonds with different metal substrates. A glovebag setup was designed for the transfer of APT samples in a controlled environment, to avoid oxidation of the samples. This allowed the comparison of oxidised and un-oxidised specimen states. In the last part of this thesis, the accuracy of crystallographic information contained within APT datasets was verified for the first time by comparing the datasets to TKD measurements.
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Gordon, Joshua Ari. "Coated Nano-particles for Optical Metamaterials and Nano-photonic Applications." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195907.
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The optical properties of a concentric nanometer-sized spherical shell comprised of an (active) 3-level gain medium core and a surrounding plasmonic metal shell are investigated. Current research in optical metamaterials has demonstrated that including lossless plasmonic materials to achieve a negative permittivity in a nano-sized coated spherical particle can lead to novel optical properties such as resonant scattering as well as transparency or invisibility. However, in practice, plasmonic materials have high losses at optical frequencies. It will be demonstrated that a properly designed passive optical spherical core impregnated with a gain medium and coated with a concentric spherical plasmonic nano-shell will have a "super resonant" (SR) lasing state. The operating characteristics of this coated nano-particle (CNP) laser have been obtained numerically for a variety of configurations and will be reported here. Once the optical properties of the isolated active CNP inclusion are established, several examples of optical metamaterials using them as inclusions will be presented and analyzed. In particular, the effective material properties of these optical MTMs will be explored using effective medium theories that are applicable to a variety of inclusion configurations. Two-dimensional (2D) mono-layers of these active CNPs, which form metafilms; three-dimensional (3D) periodic arrays of these active CNPs; and 3D random distributions of these active CNPs will be described. The effective permittivities and refractive indexes of these optical MTMs will be compared and contrasted to those of their active CNP inclusions. In addition to the active MTMs, some examples of nano-photonic applications enabled by the unique properties of these inclusions will also be presented. Specifically metamaterial pigments derived from exploiting the high absorption and low scattering properties of the passive CNP particle will be explored for possible use in color display technology as well as the use of the SR lasing state and localized plasmon resonance of the active CNP for nano-sensing applications.
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Liu, Eric Chun Yeung. "Nano dispersed materials." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488774.
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Bartlett, Thomas. "Nano-impact voltammetry." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:05ca3e7f-fea4-4d93-9f57-e86a2c397d1f.
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This thesis introduces new concepts to the study of nanoparticles by nano-impact voltammetry. Utilising the special chemistries of metal halide and metal oxide nanoparticles, the use of the nano-impact technique is expanded beyond quantitative sizing towards the study of the in-situ synthesis and detection of nanoparticles, reversible agglomeration behaviour and the fabrication of nanoelectrode arrays. Nano-impact voltammetry is also demonstrated to be an informative tool for the tracking of chemical and photochemical conversion reactions of metal halide nanoparticles and for the mechanistic determination of metallic nanoparticle growth during synthesis. The use of forced convection to gain improvements in the detection limit achievable for the direct-impact of metallic nanoparticles is also reported. Initially, the work reported herein looks at the direct-impact voltammetry of previously unstudied nanomaterials; mercury(I) chloride, silver bromide and bismuth oxide. The first sizing of metal halide nanoparticles is reported as well as a method for synthesising particles through the electrolytic induced implosion of a nanoscale metal halide layer on a liquid electrode. The "upper-limit" of the nano-impact technique is also quantified through the use of silver bromide and silver nanoparticles with diameters approaching 100 nm successfully studied. Next, bismuth oxide nanoparticles are studied by the nano-impact method to probe the reversible agglomeration of particles. By reducing impacting bismuth oxide nanoparticles at the electrode, bismuth deposits are shown to result and can be imaged by scanning electron microscopy. Through the analysis of these deposits, in combination with nanoparticle tracking analysis, experimental evidence for the voltammetrically induced de-agglomeration of nanoparticles is proposed. In the subsequent chapter, nano-impact voltammetry is employed in the study of photochemical reactions. First, the photochemical reduction of silver bromide nanoparticles to silver nanoparticles is followed both by ultra-violet visible spectroscopy and nano-impacts, allowing mechanistic determination of the conversion process. Second, the nano-impact technique is used in combination with ultra-violet visible spectroscopy and transmission electron microscopy for the mechanistic determination of the photochemical Ostwald ripening of silver nanoprisms from silver nanoseeds. Finally, the inter-play between nano-impacts and electrode arrays is reported. Through the electrolysis of impacting silver bromide nanoparticles, it is shown that a functional silver nanoelectrode array can be formed. The formed nanoelectrode array is characterised by the electrocatalytic reduction of hydrogen peroxide. The lowest reported detection limit for silver nanoparticles is also reported, through the combination of a random array of microelectrodes and a specially developed, custom built, and characterised wall-jet flow cell.
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Steiger, Sebastian. "Modelling Nano-LEDs." Konstanz Hartung-Gorre, 2009. http://d-nb.info/995394202/04.
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Castro, Olivier de. "Development of a Versatile High-Brightness Electron Impact Ion Source for Nano-Machining, Nano-Imaging and Nano-Analysis." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS468/document.
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Les nano-applications utilisant des faisceaux d'ions focalisés nécessitent des sources d'ions à haute brillance avec une faible dispersion en énergie (ΔE) ce qui permet une excellente résolution latérale et un courant d'ions suffisamment élevé pour induire des vitesses d'érosion raisonnables et des rendements élevés d'émission électronique et ionique. Les objectifs de cette thèse sont le développement d'une source d'ions basée sur l'impact électronique ayant une brillance réduite Br de 10³ – 10⁴ A m⁻² sr ⁻ ¹ V⁻ ¹, une dispersion en énergie ΔE ≲ 1 eV et un choix polyvalent d'ions. Le premier concept évalué consiste à focaliser un faisceau d'électrons à une énergie de 1 keV entre deux électrodes parallèles distant de moins d'un millimètre. Le volume d'ionisation « micrométrique » est formé au-dessus d'une ouverture d'extraction de quelques dizaines de µm. En utilisant un émetteur d'électrons LaB₆ et une pression de 0.1 mbar dans la région d'ionisation, Br est proche de 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ avec des tailles de source de quelques µm, des courants de quelques nA pour Ar⁺/Xe⁺/O₂ ⁺ et une dispersion en énergie ΔE < 0.5 eV. La brillance réduite Br est encore en dessous de la valeur minimum de notre objectif et la pression de fonctionnement très faible nécessaire pour l'émetteur LaB₆ ne peut être obtenue avec une colonne d'électrons compacte, donc ce prototype n'a pas été construit.Le deuxième concept de source d'ions évalué est basé sur l’idée d’obtenir un faisceau ionique à fort courant avec une taille de source et un demi-angle d’ouverture similaire aux résultats du premier concept de source, mais en changeant l’interaction électron-gaz et la collection des ions. Des études théoriques et expérimentales sont utilisées pour l’évaluation de la performance de ce deuxième concept et de son utilité pour les nano-applications basées sur des faisceaux d'ions focalisés<br>High brightness low energy spread (ΔE) ion sources are needed for focused ion beam nano-applications in order to get a high lateral resolution while having sufficiently high ion beam currents to obtain reasonable erosion rates and large secondary electron/ion yields. The objectives of this thesis are: the design of an electron impact ion source, a reduced brightness Br of 10³ – 10⁴ A m⁻² sr⁻ ¹ V⁻ ¹ with an energy distribution spread ΔE ≲ 1 eV and a versatile ion species choice. In a first evaluated concept an electron beam is focussed in between two parallel plates spaced by ≲1 mm. A micron sized ionisation volume is created above an extraction aperture of a few tens of µm. By using a LaB₆ electron emitter and the ionisation region with a pressure around 0.1 mbar, Br is close to 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ with source sizes of a few µm, ionic currents of a few nA for Ar⁺/Xe⁺/O₂ ⁺ and the energy spread being ΔE < 0.5 eV. The determined Br value is still below the minimum targeted value and furthermore the main difficulty is that the needed operation pressure for the LaB₆ emitter cannot be achieved across the compact electron column and therefore a prototype has not been constructed. The second evaluated source concept is based on the idea to obtain a high current ion beam having a source size and half-opening beam angle similar to the first concept, but changing the electron gas interaction and the ion collection. Theoretical and experimental studies are used to evaluate the performance of this second source concept and its usefulness for focused ion beam nano-applications
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Zhang, Li 1973. "Shockwave consolidation of nano silver powder into bulk nano structured silver." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100238.
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Bulk nanostructured silver components were fabricated from nano-sized powder using a shockwave consolidation technique. The grain size evolution during compaction, the mechanical properties of the bulk components, and the effect of surface finish on the mechanical behavior were studied. X-Ray diffraction, transmission electron microscopy (TEM), atomic force microscopy (AFM), microhardness, compression testing and shear punch testing at room temperature were used to characterize the materials. Upon consolidation, the average grain size calculated from image analysis of the TEM micrographs was 49+/-22 nm, showing the feasibility of maintaining a nanostructure upon dynamic consolidation. The hardness of the bulk nanostructured components was constant across the diameter with an average of 83+/-1 HV. Compression results showed strength about 390+/-10 MPa and ductility of 23+/-2%, which is well above strength level obtainable from strain hardened Ag components. The AFM results show that samples possessing a surface roughness of 267 nm exhibited a brittle behavior and a reduction in strength of 35% when compared to the smoother surfaces. Dimples were observed for the samples exhibiting plasticity, while an intergranular pattern was identified for the brittle materials. Fracture toughness of 0.2 MPa m was calculated, which confirms the strong relationship between fracture toughness and defects observed in nanomaterials.
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Gütter, Friederike [Verfasser]. "Understanding nano-stabiliser and nano-bio interactions of nanocrystals / Friederike Gütter." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1159900507/34.
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Wang, Feng. "Modes, Excitation and Applications of Plasmonic Nano-apertures and Nano-cavities." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1348588159.
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Li, Bo. "An inductive superconducting transition-edge nano-detector for nano-dosimetry applications." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/848851/.
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In this thesis I have demonstrated the feasibility of using Inductive Superconducting Transition-Edge Sensor (ISTED) as an excellent nanodosimeter for nano-dosimetry applications. This thesis can be divided broadly into two parts. In the first part, I begin by addressing how the study of low energetic ionising particles in liquid water using concepts from classical mechanics is a valid approach, despite being inside the quantum-classical boundary regime. Based on the circumstantial validity condition, I showed that the percentage uncertainties in nanodosimetric quantities due to Heisenberg's uncertainty principle for sub- 1 keV electrons in liquid water as calculated by GEANT4-DNA is not significant enough to cause changes to their distributions. Important nanodosimetric quantities studied in details are ionisation cluster-size distribution, second order of moment for cluster-size distribution (M₂) and the cumulative frequency of ionisation cluster-size distribution from cluster-size two (F₂). In the second part of my thesis, I have focussed on the design, optimisation, fabrication, characterisation of the superconducting devices. An ISTED is made from three components: a) a Superconducting Quantum Interference Device (SQUID), b) a superconducting thin-film and c) a top layer of thin-film Carbon absorber. I have measured the magnetic flux noise of a nanoSQUID of loop dimension 350 nm and nano- Josephson junctions of dimensions 65 nm x 65 nm as 3 x 10⁻¹⁴ Φ₀² in the white noise region. It is shown that the measured nanoSQUID is more than capable of sub- 10 eV energy detection.
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Hargreaves, Natasha Jayne. "Crystallisation of nano-quartz and nano-graphite from microemulsions under ambient conditions." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11725/.
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The principal basis for the following work is to demonstrate the importance of controllable crystallisation and consequential applications for both silica-based significant inorganic materials and carbonaceous materials. Microemulsions have been employed as a vector to explore the possibility of thermodynamically controlling the crystallisation process, utilising the 3D confinement of crystallisable material within nano-scale droplets. This opens a route to circumvent Ostwald’s Rule of Stages, for a multitude of potential applications. We show here that both quartz and nanographite can be synthesised at room temperature and pressure using this methodology. Previous attempts at silica synthesis from within the microemulsion have only presented the amorphous phase, leaving many questions unanswered, whilst failing to reveal the underlying cause. Further, traditional methods of quartz synthesis employs hydrothermal conditions, or temperatures >1100 0C. Microemulsions were adopted to behave as confined mini reactors for the synthesis of α-quartz at room temperature and pressure from a precursor from sodium metasilicate nonahydrate (SMS) which can be used as a precursor of silica, circumnavigating the traditional hydrothermal methodologies. At higher supersaturations, both the metastable amorphous phase and the high temperature polymorph, cristobalite were also observed. Upon the acidification of the microemulsions, the size and morphology of the quartz nanoparticles was found to be dependent upon the pH and the ratio of surfactant:silica units. Conventional wisdom stipulates that graphite can only be produced using high temperatures, with natural graphite arising via progressive metamorphisms of carbonaceous material subjected to temperatures above ~600 K and pressures >2 kbar. Previous attempts to use carbohydrate precursors have resulted in the formation of luminescent carbon dots or required templation, followed by calcination. In these prior investigations, high temperatures or extremely severe reactants are used to drive the precipitation of graphitic forms. Analogous experiments were successful in employing the 3D nano-confinement microemulsions as confined mini reactors for the synthesis of nanographite at room temperature and pressure from a sucrose precursor, through a simple process of acidifying sucrose microemulsions. Crucially, the reaction was conducted in nanometre-sized microemulsion droplets to exert control over the reaction and sheet stacking process, ensuring that only sufficiently pristine graphene nanosheets could stack, thereby producing nanographite in a simple one-step synthesis under ambient conditions. The primary nanographitic particles of size ~3-30 nm stacked to form larger µm-sized nanographitic aggregates. The amount of nanographite produced from the microemulsions is limited as sucrose concentration must be kept very low to slow the reaction kinetics to ensure the mainly graphitic, rather than amorphous, product.
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Jung, Anne [Verfasser], and Rolf [Akademischer Betreuer] Hempelmann. "Galvanoformen von nano-Nickel und nano-Invar / Anne Jung. Betreuer: Rolf Hempelmann." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2013. http://d-nb.info/1052781292/34.
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Anand, Deepti. "SORPTION OF CHLORINATED COMPOUNDS ON CARBON NANO TUBES AND NANO TEXTURED SAND." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/348.
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The release of carbon-based nanomaterials into the environment is causing great concern among environmental scientists and engineers due to their potential impacts on the fate and transport of environmental contaminants, deriving from their superior adsorption capacities. Chlorinated compounds are one of the most prevalent environmental contaminants in the United States, yet systematic studies concerning the adsorption and desorption mechanisms of chlorinated compounds on carbon nanotubes (CNTs) are scant. The objective of this study was to investigate the adsorption and desorption mechanisms of three chlorinated compounds with different molecular structures on multi-wall carbon nanotubes (MWCNTs) using a wide range of isotherms that were used as models to predict the adsorptive capacity of the MWCNT's. The results indicated that sorption capacities of chlorinated compounds to MWCNTs are greatly affected by the molecular structures and follows an order of 1,1,1-TCA < TCE < 1,3,5-TCB. Hysteresis was observed for all compounds on pristine MWCNTs. After thermal treatment of MWCNTs, sorption capacity of all three compounds was enhanced and sorption hysteresis was considerably reduced. The results highlighted the role of disorderly amorphous carbon in the adsorption and desorption process. We also conducted a study on how nano-texturing of sand surfaces using carbon nanotubes (CNT) can efficiently control the mobility and bioavailability of contaminants found in aquatic sediments. The CNT textured sand can be used as viable in-situ capping (ISC) materials to physically separate contaminated sediments from overlying water. Adsorption measurements of several common contaminants (chlorinated aliphatics) found in aquatic environment performed on CNT textured sand showed at least an order of magnitude increase in their sorption coefficients compared to traditional capping materials such as sand. It was also demonstrated that CNT textured sand can significantly reduce the migration of contaminants from sediments to overlying water and possess suitable geotechnical parameters needed for contaminant sequestration and sediment remediation technologies which can lead to clean and healthy aquatic environment.
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Gunputh, Urvashi Fowdar. "Antibacterial properties of TiO2 nanotubes coated with nano-ZnO and nano-Ag." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/11155.
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TiO2 nanotubes grown on titanium alloy are known to increase the biocompatibility of the alloy when used in dental/orthopaedic implants. Furthermore, their nanotubular structures can act as antibacterial agent carrier and as a scaffold for tissue engineering with the aim of adding antibacterial properties to the implant. This study aims at fabricating an antibacterial and biocompatible nanocomposite coating on Ti-6Al-4V involving nano-ZnO and nano-Ag. Initially, TiO2 nanotubes were self-assembled on the polished surface of medical grade Ti-6Al-4V alloy discs using anodisation. First silver nanoparticles were chemically reduced from silver ammonia using delta-δ-gluconolactone for different duration on the nanotubes to form TiO2-Ag composite coating. Nano HA was added to the latter coating with the aim of reducing toxicity from silver, hence forming TiO2-Ag-HA coating. Secondly, nano-ZnO was thermo-chemically grown on the TiO2 nanotubes using zinc nitrate and hexamethylenetetramine. They were then annealed at 350-550 oC hence forming TiO2-ZnO. HA was grown on the latter coating by a biomimetic method whereby the coated discs were placed in a concentrated simulated body fluid at 37 oC forming TiO2-ZnO-HA. The stability of the 4 coatings, TiO2-Ag, TiO2-Ag-HA, TiO2-ZnO and TiO2-ZnO-HA were assessed using the dialysis method (n=3 each) and then exposed to S.aureus for 24 hours in BHI broth. Their antibacterial properties were assessed using different assays and microscopic imaging with respect to different controls (n=6 each for assays and n=3 for imaging). Their biocompatibility properties were assessed in the presence of primary human osteoblast cells in DMEM media with the help of biochemical assays, molecular gene expression and microscopic imaging (n=3). Both silver and zinc coated nanotubes showed significant level of antibacterial properties with silver coating being more bactericidal than the coating containing zinc. Nonetheless, the zinc oxide coatings were more biocompatible than the silver coating. Nano silver and zinc oxide containing composite coatings were successfully synthesised and tested in the presence of bacteria and human cells. The final conclusion was that nano-silver was still toxic and nano-ZnO coatings were more biocompatible.
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Reichel, René. "Nano Scale Cluster Devices." Thesis, University of Canterbury. Physics and Astronomy, 2007. http://hdl.handle.net/10092/1385.
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This study uses clusters formed in a UHV-compatible cluster apparatus, which was built and commissioned during this thesis. The design and operation of the cluster deposition system is described. This system is optimised for high clus- ter fluxes and for the production of cluster assembled nanoscale devices. One key feature of the system is a high degree of flexibility, including interchangeable sputtering and inert gas aggregation sources, and two kinds of mass spectrome- ter, which allow both characterisation of the cluster size distribution and deposi- tion of mass-selected clusters. Another key feature is that clusters are deposited onto electrically contacted lithographically defined devices mounted on an UHV- compatible cryostat cold finger, allowing deposition at room temperature as well as at cryogenic and at elevated temperatures. The electrically contacted nanoscale cluster devices were fabricated using a novel template technique. Hereby, clusters are placed between two electrodes separated only by ∼100 nm. The width of the cluster ensemble is in the order of a few cluster diameters, which means that the assembled clusters form a cluster wire bridging the electrode separation. During this thesis, the design and layout has been optimised to be able to measure electrical properties of the cluster devices and in particular to investigate the interaction between the cluster ensemble and the contact electrodes. In-situ electrical characterisation of cluster assembled nanoscale devices are performed in the temperature range 4.2 K to 375 K. The samples are provided with a backgate, which in principle allows modification of the conduction through the cluster ensemble by applying a gate voltage. However, no change in conduc- tion with changes in gate voltages was seen. The main focus of the electrical measurements is on the current voltage char- acteristics. It was noticed that the nanoscale bismuth (and antimony) cluster devices exhibited non-linear current voltage characteristics, which were in stark contrast to the linear current voltage characteristics measured for cluster films previously. Investigations into the causes of this non-linearity suggests that tun- nelling conduction occurs between the cluster ensemble (wire) and the contact electrodes. The non-linear current voltage characteristics were fitted using three models of tunnelling conduction and appear to be best fitted using a model in- volving fluctuation-assisted tunnelling through barriers of different heights. Further, measurements of the temperature dependent resistance are performed showing an increase of resistance with decreasing temperature for bismuth and antimony assembled cluster devices. The temperature dependence of bismuth as- sembled cluster wires can be explained by the decrease of the carrier concentration in bismuth for decreasing temperature. Annealing of the cluster ensemble and the cluster contact connection resulted in an increase in conduction. This increase of conduction can be explained due to the current flow through the cluster wire. Locally, at the bottlenecks, the current flow causes resistive heating and subsequently coalescence of two (or more) clusters.
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Chakraborty, Dipanjan, Frank Cichos, and Klaus Kroy. "Simulating hot nano beads." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190665.
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Chakraborty, Dipanjan, Frank Cichos, and Klaus Kroy. "Simulating hot nano beads." Diffusion fundamentals 11 (2009) 71, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14036.
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Shamshurov, A. V., V. M. Beresnev, and N. A. Volovicheva. "Nano-reinforced Quartz Composites." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35246.
Full textAbstract:
We have studied the process of interaction between the components in the system «β-SiO2–Fe3O4–Na2O» in the temperature range from 20 to 1100 °C. Nano-reinforced composite building materials were developed on the base of quartz raw material. Developed materials are produced by low-temperature cal-cining technology.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35246
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Cheng, Ka Ying. "Nano-metals plasmonic coupling." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/747.
Full textAbstract:
In this work, we investigated nano-metal plasmonic coupling between dissimilar metals. We measured the optical transmission of nano-Ag coupled to other nano-metals using glass and Si substrates respectively. The reflected colors shifted from yellow to violet were obtained through the plasmonic coupling with nearest-neighbor nano-metals such as aluminum, magnesium, and ytterbium nano-metals. They were deposited randomly next to the nano-Ag. The metal size is from 8 to 15 nanometers. The results show that the colors changing is essentially due to plasmonic coupling between nano-Ag and another the nano-metals e.g. nano-Al The coupling caused a red shift in plasmonic resonance frequency, thus, changing the reflection color. The resonance shift agrees well with the simulation result using COMSOL. The inter-particle distance and particle size dependency of the optical spectra correspond to surface plasmon resonance extinction peaks for isolated nano-Ag and coupled with those neighboring nano- metals. Due to plasmonic coupling between nanoparticles in small space can create new resonances; red shifts as the interparticle distance reduce. Wavelengths are tuned by the extent of the interparticles interactions which relate to the particles size, interparticles distance and the similarity of nano metals. Using different nano metals to fabricate thin films can change the plasmonic resonance frequency which makes the reflected colours become multihued. When we look into the effect of the nano-particle size, and the distance between nano-particles, we discovered that larger nano-particle size has larger distance between the particles, and since the plasmonic coupling is a function of Inverse Square of the distance between particles. Therefore, smaller nano-particles have the strongest plasmonic coupling. Al produced the smallest nano-particle therefore it has the shortest distance between nano-Al and nano-Ag. Since the size of the particles can be controlled during deposition, the color changing of nano-Ag can be well defined. Thus tunable color changing devices can be fabricated
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CANDITO, MARIARITA. "Nano ingegnerizzazione dell'orecchio umano." Doctoral thesis, Università degli studi di Padova, 2022. http://hdl.handle.net/11577/3458324.
Full textAbstract:
Sensorineural hearing loss (SNHL) is the most common permanent ear disorder affecting people worldwide. The treatment of profound SNHL requires the use of a cochlear implant whose implantation has many disadvantages related to its construction and to quality of life of implanted patient. Thus, scientists are working on innovative cochlear implants to achieve a better hearing sensitivity and quality in deaf population.
Another common ear disorder is the perforation of the tympanic membrane. In case of serious perforation, the surgical treatments currently used are the myringoplasty and the tympanoplasty but, both techniques have suboptimal outcome. For this reason, many studies are focused on the creation of scaffolds, to be used in tympanic membrane regeneration.
The aim of this thesis was to analyse the in vitro biocompatibility and efficacy of new nanomaterials and biomaterials to be used in the inner and middle ear, for functional recovery or replacement of damaged tissues and cells.
Firstly, the biocompatibility of piezoelectric nanoparticles barium titanate and lithium niobate was analysed on two different cell lines, an Organ of Corti cell line (OC-k3) and a neuron-like cell line deriving from rat pheochromocytoma (PC12). These piezoelectric nanoparticles are involved in the construction of an innovative “self-powered” cochlear implant, which, by exploiting its piezoelectric features, will stimulate the cochlear neurons bypassing the damaged inner ear cells. The biocompatibility study was assessed by analysing cytotoxic, apoptotic, oxidative and neurotoxic stimuli.
In the second part of the study, the aim was to analyse the biocompatibility of different patches and nanoparticles involved in the construction of biodegradable scaffolds produced using copolymers of poly(ethylene oxide-terephthalate)/poly(butylene terephthalate) (PEOT/PBT), containing chitin nanofibrils (CNs), and covered by different types of nanoparticles loaded with the antibiotic ciprofloxacin. These biocompatible devices aim to facilitate the healing process of the tympanic membrane by improving the proliferation and migration of keratinocytes and by reducing the middle ear inflammation and the incidence of infection during the wound healing process. The biocompatibility was assessed on OC-k3 cells by analysing the cytotoxicity and the morphological changes induced by the PEOT/PBT copolymers containing different (w/w %) weight ratio of CNs: polyethylene glycol (PEG) pre-composite; and of the ciprofloxacin-loaded poly (lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), molecular imprinting (MIPNP) and non-molecular imprinting (NIPNP) nanoparticles.
The results showed that barium titanate and lithium niobate did not induce any cytotoxic or apoptotic effects on OC-k3 and PC12 cells, but actually increased cell viability and improved neuritic network. These piezoelectric nanoparticles appear biocompatible for inner ear cells and are good candidates for improving the efficiency of new implantable hearing devices without damaging neurons. Overall, these results confirm that the electric stimulation has neuromodulatory effects on neurons and highlight the importance of developing new scaffolds coated with piezoelectric nanoparticles to be exploited in the treatment of neuronal diseases.
Concerning the second part of this project, the results showed the biocompatibility of all materials involved in the production of the biodegradable scaffolds made of the PEOT/PBT copolymers, containing CNs, and covered by ciprofloxacin loaded nanoparticles, on the inner ear cell line OC-k3. Although further tests are required to clarify the effects of these materials, the construction of scaffolds containing chitin nanofibrils and ciprofloxacin-loaded nanoparticles, could be a great advantage for new implantable biodegradable devices to be used for repair of damaged tympanic membrane, without inducing any toxic effects on the delicate inner ear cells.<br>Sensorineural hearing loss (SNHL) is the most common permanent ear disorder affecting people worldwide. The treatment of profound SNHL requires the use of a cochlear implant whose implantation has many disadvantages related to its construction and to quality of life of implanted patient. Thus, scientists are working on innovative cochlear implants to achieve a better hearing sensitivity and quality in deaf population.
Another common ear disorder is the perforation of the tympanic membrane. In case of serious perforation, the surgical treatments currently used are the myringoplasty and the tympanoplasty but, both techniques have suboptimal outcome. For this reason, many studies are focused on the creation of scaffolds, to be used in tympanic membrane regeneration.
The aim of this thesis was to analyse the in vitro biocompatibility and efficacy of new nanomaterials and biomaterials to be used in the inner and middle ear, for functional recovery or replacement of damaged tissues and cells.
Firstly, the biocompatibility of piezoelectric nanoparticles barium titanate and lithium niobate was analysed on two different cell lines, an Organ of Corti cell line (OC-k3) and a neuron-like cell line deriving from rat pheochromocytoma (PC12). These piezoelectric nanoparticles are involved in the construction of an innovative “self-powered” cochlear implant, which, by exploiting its piezoelectric features, will stimulate the cochlear neurons bypassing the damaged inner ear cells. The biocompatibility study was assessed by analysing cytotoxic, apoptotic, oxidative and neurotoxic stimuli.
In the second part of the study, the aim was to analyse the biocompatibility of different patches and nanoparticles involved in the construction of biodegradable scaffolds produced using copolymers of poly(ethylene oxide-terephthalate)/poly(butylene terephthalate) (PEOT/PBT), containing chitin nanofibrils (CNs), and covered by different types of nanoparticles loaded with the antibiotic ciprofloxacin. These biocompatible devices aim to facilitate the healing process of the tympanic membrane by improving the proliferation and migration of keratinocytes and by reducing the middle ear inflammation and the incidence of infection during the wound healing process. The biocompatibility was assessed on OC-k3 cells by analysing the cytotoxicity and the morphological changes induced by the PEOT/PBT copolymers containing different (w/w %) weight ratio of CNs: polyethylene glycol (PEG) pre-composite; and of the ciprofloxacin-loaded poly (lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), molecular imprinting (MIPNP) and non-molecular imprinting (NIPNP) nanoparticles.
The results showed that barium titanate and lithium niobate did not induce any cytotoxic or apoptotic effects on OC-k3 and PC12 cells, but actually increased cell viability and improved neuritic network. These piezoelectric nanoparticles appear biocompatible for inner ear cells and are good candidates for improving the efficiency of new implantable hearing devices without damaging neurons. Overall, these results confirm that the electric stimulation has neuromodulatory effects on neurons and highlight the importance of developing new scaffolds coated with piezoelectric nanoparticles to be exploited in the treatment of neuronal diseases.
Concerning the second part of this project, the results showed the biocompatibility of all materials involved in the production of the biodegradable scaffolds made of the PEOT/PBT copolymers, containing CNs, and covered by ciprofloxacin loaded nanoparticles, on the inner ear cell line OC-k3. Although further tests are required to clarify the effects of these materials, the construction of scaffolds containing chitin nanofibrils and ciprofloxacin-loaded nanoparticles, could be a great advantage for new implantable biodegradable devices to be used for repair of damaged tympanic membrane, without inducing any toxic effects on the delicate inner ear cells.
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Alipour, Skandani Amir. "Computational and Experimental Nano Mechanics." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64869.
Full textAbstract:
The many advances of nano technology extensively revolutionize mechanics. A tremendous need is growing to further bridge the gap between the classical mechanics and the nano scale for many applications at different engineering fields. For instance, the themes of interdisciplinary and multidisciplinary topics are getting more and more attention especially when the coherency is needed in diagnosing and treating terminal diseases or overcoming environmental threats. The fact that how mechanical, biomedical and electrical engineering can contribute to diagnosing and treating a tumor per se is both interesting and unveiling the necessity of further investments in these fields. This dissertation presents three different investigations in the area of nano mechanics and nano materials spanning from computational bioengineering to making mechanically more versatile composites.
The first part of this dissertation presents a numerical approach to study the effects of the carbon nano tubes (CNTs) on the human body in general and their absorbability into the lipid cell membranes in particular. Single wall carbon nano tubes (SWCNTs) are the elaborate examples of nano materials that departed from mere mechanical applications to the biomedical applications such as drug delivery vehicles. Recently, experimental biology provided detailed insights of the SWCNTs interaction with live organs. However, due to the instrumental and technical limitations, there are still numerous concerns yet to be addressed. In such situation, utilizing numerical simulation is a viable alternative to the experimental practices. From this perspective, this dissertation reports a molecular dynamics (MD) study to provide better insights on the effect of the carbon nano tubes chiralities and aspect ratios on their interaction with a lipid bilayer membrane as well as their reciprocal effects with surface functionalizing. Single walled carbon nano tubes can be utilized to diffuse selectively on the targeted cell via surface functionalizing. Many experimental attempts have smeared polyethylene glycol (PEG) as a biocompatible surfactant to carbon nano tubes. The simulation results indicated that SWCNTs have different time-evolving mechanisms to internalize within the lipid membrane. These mechanisms comprise both penetration and endocytosis. Also, this study revealed effects of length and chirality and surface functionalizing on the penetrability of different nano tubes.
The second part of the dissertation introduces a novel in situ method for qualitative and quantitative measurements of the negative stiffness of a single crystal utilizing nano mechanical characterization; nano indentation. The concept of negative stiffness was first introduced by metastable structures and later by materials with negative stiffness when embedded in a stiffer (positive stiffness) matrix. However, this is the first time a direct quantitative method is developed to measure the exact value of the negative stiffness for triglycine sulfate (TGS) crystals. With the advancements in the precise measuring devices and sensors, instrumented nano indentation became a reliable tool for measuring submicron properties of variety of materials ranging from single phase humongous materials to nano composites with heterogeneous microstructures. The developed approach in this chapter of the dissertation outlines how some modifications of the standard nano indentation tests can be utilized to measure the negative stiffness of a ferroelectric material at its Curie temperature.
Finally, the last two chapters outline the possible improvements in the mechanical properties of conventional carbon fiber composites by introducing 1D nano fillers to them. Particularly, their viscoelastic and viscoplastic behavior are studied extensively and different modeling techniques are utilized. Conventional structural materials are being replaced with the fiber-reinforced plastics (FRPs) in many different applications such as civil structures or aerospace and car industries. This is mainly due to their high strength to weight ratio and relatively easy fabrication methods. However, these composites did not reach their full potential due to durability limitations. The majorities of these limitations stem from the polymeric matrix or the interface between the matrix and fibers where poor adhesion fails to carry the desired mechanical loadings. Among such failures are the time-induced deformations or delayed failures that can cause fatal disasters if not taken care of properly. Many methodologies are offered so far to improve the FRPs' resistance to this category of time-induced deformations and delayed failures. Several researchers tried to modify the chemical formulation of polymers coming up with stiffer and less viscous matrices. Others tried to modify the adhesion of the fibers to the matrix by adding different chemically functional groups onto the fibers' surface. A third approach tried to modify the fiber to matrix adhesion and at the same time improve the viscous properties of the matrix itself. This can be achieved by growing 1D nano fillers on the fibers so that one side is bonded to the fiber and the other side embedded in the matrix enhancing the matrix with less viscous deformability. It is shown that resistance to creep deformation and stress relaxation of laminated composites improved considerably in the presence of the nano fillers such as multiwall carbon nano tubes (MWCNTs) and zinc oxide nano wires (ZnO- NWs). The constitutive behaviors of these hybrid composites were investigated further through the use of the time temperatures superposition (TTS) principle for the linear viscoelastic behavior and utilizing phenomenological models for the viscoplastic behavior.<br>Ph. D.
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Ignacio, Maxime. "Étude théorique du mouillage de nano-cristaux solides sur des substrats nano-patternés." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10231/document.
Full textAbstract:
A l'échelle nanométrique, les solides peuvent changer de forme par diffusion de surface, et présentent alors des propriétés de mouillage qui s'apparentent à celles des liquides. Dans cette thèse, nous nous sommes plus particulièrement intéressés au comportement de mouillage des nano-solides sur des substrats nanopatternés, comportant par exemple des piliers ou des tranchées. Sur ces substrats, les nanoparticules (ou ilots) solides peuvent être multi-stables : c'est-à-dire qu'ils peuvent présenter plus d'un état localement stable. Comme les liquides, les solides ont été observés par exemple dans des états dits de Wenzel (pénétrant dans la structure du substrat) ou de Cassie-Baxter (ne pénétrant pas). Grâce à une combinaison de simulations Monte Carlo Cinétiques et de modèles analytiques, nous avons étudié la stabilité de ces états et leur dynamique de transition. Plus particulièrement, avons mis en évidence le rôle de la diffusion de surface et de la nucléation bidimensionnelle sur la dynamique de transition. Nous avons aussi montré que les contraintes élastiques augmentent la stabilité des états de Cassie-Baxter, et mènent à de nouveaux états, avec des morphologies asymétriques ou partiellement empalées dans les nanostructures. Finalement, nous avons proposé de contrôler les transitions de mouillage à l'aide de l'électromigration induite par un faisceau d'électrons. Nos résultats ouvrent la voie vers une nouvelle direction pour les investigations expérimentales<br>At the nanometer scale, solids can change shape thanks to surface diffusion and therefore display wetting properties that can be likened to those of liquids. This doctoral thesis intends to study particularly the wetting behaviour of nano-solids located on nanopatterned substrates, containing for instance pillars or trenches. Upon these substrates, solid nanoparticles (or islands) can be multi-stable – that is to say they can display more than one locally-stable state. Just like liquids, solids have been observed for example in the context of the so-called Wenzel state (penetrating the very structure of the substrate) and Cassie-Baster state (no penetration). By combining Kinetic Monte Carlo simulations with analytical models, we conducted a study on the stability of these states along with their dynamics of transition. In particular, we highlighted the specific roles that surface diffusion and bidimensional nucleation play in regards to the dynamics of transition. We also demonstrated that elastic constraints increase the stability of Cassie-Baxter states and lead to new states, with either asymmetric morphologies or morphologies that are partially impaled into the nanostructures. Last but not least, we proposed to control wetting transitions using the electromigration brought on by an electron beam. Our results pave the way for a new direction in the field of experimental investigations
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Sveaass, Tore. "Nano-Indentation of Anisotropic Material: Numerical Approaches to Extract Elasticities from Nano-Indentation." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22621.
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Division of Biomechanics participates in a project together with Department of Cancer Research and Molecular Medicine, NTNU, on effects of proton pump inhibitor medication on bone quality. This common anti-stomach acid medication seems to result in an increased bone fragility in humans. As a step towards comparing mechanical properties at micro level, between sick and healthy bone tissue, mice femur have been tested at micro level using the increasingly popular tool, nanoindentation. Futher, an analytical finite element model has been created in an effort to increase the understanding of nanoindentation of bone. It is concluded that the experimental protocol is not accurate enough(SD ~ 5GPa for reduced Young's modulus) as a result of multiple factors, mainly indentation locations. The experimental results were compared to the finite element model. It was possible to match the data curves of the experimental tests with the analytical tests by adjusting the model parameters. Unfortunatly, this resulted in divergent results(plastic yield stress of ~ 600MPa and reduced Young's modulus of nearly 60% of the experimental data(32,45 GPa and 20GPa). As an effort to reduce the divergence between the experimental and analytical testing, multiple suggestions were made.
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Wong, Basil T. "THERMAL HEAT TRANSPORT AT THE NANO-SCALE LEVEL AND ITS APPLICATION TO NANO-MACHINING." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/387.
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Nano-manufacturing is receiving significant attention in industry due to the ever-growing interest in nanotechnology in research institutions. It is hypothesized that single-step or direct-write nano-scale machining might be achieved by coupling nano-probe field emission with radiation transfer. A laser may be used to heat a workpiece within a microscopic region that encloses an even smaller nanoscopic region subjected to a focused electron beam. The electron-beam supplies marginal heat sufficient to remove a minute volume of material by evaporation or sublimation. Experimentally investigating this hypothesis requires an estimate of the power needed in the electron-beam. To this end, a detailed numerical study is conducted to study the possibility of using the nano-probe field emission for nano-machining. The modeling effort in this case is divided into two parts. The first part deals with the electron-beam propagation inside a target workpiece. The second part considers the temperature increase due to the energy transfer between the electron-beam and the workpiece itself. A Monte Carlo/Ray Tracing technique is used in modeling the electron-beam propagation. This approach is identical to that of a typical Monte Carlo simulation in radiative transfer, except that proper electron scattering properties are employed. The temperature distribution inside a gold film is predicted using the heat conduction equations. Details of the various numerical models employed in the simulation and a series of representative results will be presented in this dissertation.
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Stattersfield, Eloise Helen. "Nano-necklaces : the interaction between high molecular weight polymers and nano-sized colloidal particles." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420917.
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Gaucher, Fabien. "Nano-structures en La2/3Sr1/3MnO3 : de la nano-structuration aux propriétés de transport." Paris 11, 2008. http://www.theses.fr/2008PA112271.
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Les travaux reportés dans ce manuscrit présentent la fabrication et l'étude des propriétés de transport de nano-structures de demi-métal La2/3Sr1/3MnO3 (LSMO). L'optimisation du procédé de nano-structuration, et notamment des étapes de lithographie électronique et de gravure, a permis l'obtention de nano-fils larges de seulement 65 nm et longs de plusieurs microns. L'analyse fine des propriétés de transport montre une conservation de celles-ci jusqu'à une épaisseur réduite d'environ 7 nm. La conduction du courant est alors limitée par différents modes de diffusion selon la gamme de température considérée. Des premières mesures de bruit mettent en avant un faible paramètre de Hooge normalisé ( ≈ 1. 10-32 m3). L'observation de bruit télégraphique dans une fenêtre étroite de température (220 K < T < 245 K) pour le nano-fil le plus étroit et le plus fin est la signature d'une réduction notable du nombre de porteurs de charge à cette échelle. Nous pouvons alors imaginer l'utilisation du LSMO comme électrode de courant totalement polarisé en spin pour l'adressage de molécules magnétiques. Dans cette voie, l'ancrage direct de l'aimant moléculaire Mn12 a été prouvé et ouvre des perspectives intéressantes pour la réalisation d'une vanne de spin moléculaire<br>The works reported in this manuscript present the fabrication and the investigation of the transport properties of half-metallic La2/3Sr1/3MnO3 (LSMO) nano-structures. The optimization of the nano-sructuration process, particularly the electron-beam lithography and the etching steps, allowed the realization of nanowires with width down to 65 nm wide and length of several microns. The fine analysis of the transport properties shows their preservation until a thickness reduced to about 7 nm. The current conduction is then limited by different diffusion modes, depending on the temperature range. First noise measurements exhibit a very low normalized Hooge parameter ( ≈ 1. 10-32 m3). The observation of random telegraphic noise for the narrowest and thinnest nanowire in a narrow temperature range (220 K < T < 245 K) is the signature of a consequent reduction of the charge carriers at this scale. We can then imagine to use the LSMO as a full spin-polarized electrode for molecular magnets addressing. In this way, direct grafting of Mn12 magnetic molecules was prooved and opens interesting perspectives for the realization of a molecular spin valve
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Sriraman, Sharan Ram. "Pool boiling on nano-finned surfaces." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2091.
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Makhsiyan, Mathilde. "Nano-émetteurs thermiques multi-spectraux." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX048/document.
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Les sources infrarouges sont indispensables à la détection locale de gaz dans de nombreux domaines, que ce soit pour l'environnement (détection de polluants et gaz à effets de serre) ou la défense (détection de menaces biologiques et chimiques). Elles sont également nécessaires en tant que mires de calibration pour le développement de caméras multispectrales infrarouges. Pour toutes ces applications, il est nécessaire de disposer de sources performantes, capables d'émettre un rayonnement spécifique dans une direction donnée. L'objectif de cette thèse est de concevoir des sources thermiques infrarouges compactes et à coût modéré, à spectre accordable et à pertes réduites, pouvant être juxtaposées dans un même dispositif. Pour cela, ces travaux s'organisent autour de deux axes. Le premier concerne l'étude de nouveaux matériaux nanostructurés résonants, appelés métamatériaux ou métasurfaces selon les directions de la structuration, permettant de contrôler l'émissivité spectrale et spatiale afin de maîtriser la réponse spectrale en tout point. Cette étude repose à la fois sur des simulations numériques et sur des mesures expérimentales et démontre le potentiel de ces résonateurs pour la conception de sources thermiques accordables. Cependant, ces matériaux étant composés de métal, ils présentent des pertes par absorption dans l'infrarouge qui limitent leurs performances. Le deuxième axe de recherche est alors de gérer les pertes liées à l'utilisation de métaux grâce à une ingénierie des champs dans des métamatériaux, menant à des émissions spectralement très fines. Les résultats obtenus sur ce contrôle des pertes ouvrent de nombreuses perspectives pour tout le domaine des métamatériaux<br>Infrared sources are essential for local gas detection for civil applications (detection of pollutant and greenhouse gas) or military applications (detection of chemical and biological threats). They are also used as calibration targets for the development of multispectral infrared cameras. For these applications, the sources must be efficient and able to emit a specific light in a given direction. The aim of this thesis is to develop infrared thermal emitters with the following features: low cost with a compact volume, with a tunable spectral response and low losses, able to be juxtaposed on the same device. This work begins with the study of new resonant nanostructured materials, called metamaterials or metasurfaces according to the direction of the structuration, that spectrally and spatially control the emitted light up to the wavelength scale. This study relies on numerical simulations and experimental measurements and demonstrates the potential of these resonators as tunable thermal sources. However, due to the use of metals in these materials, their performance is limited by metal losses. The second study of this work is then to deal with these losses thanks to a field engineering in metamaterials, leading to very narrow spectral responses. The results on this loss control open up promising breakthroughs in the plasmonic and metamaterials field
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Pack, Andreas. "Current Problems in Nano-Optics." Doctoral thesis, [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=968778364.
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Cerf, Aline. "Assemblage dirigé de nano-objets." Phd thesis, INSA de Toulouse, 2010. http://tel.archives-ouvertes.fr/tel-00525067.
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Un échange vigoureux au travers des frontières de la biologie et de la physique se développe autour de nouvelles méthodes et outils, et autour de nouveaux phénomènes. Les objets d'étude au coeur de ce recouvrement multidisciplinaire sont très divers. De manière non exhaustive, il s'agit de nanoparticules, de cellules ou encore d'objets encore plus petits et élémentaires tels que les molécules. Aussi bien pour des applications dans le domaine de la microélectronique que pour l'étude de mécanismes biologiques fondamentaux, l'intégration des objets d'intérêt à l'échelle de l'objet unique est essentielle. Dans le cadre de cette thèse, l'objectif que nous nous sommes fixés est de développer un volet technologique qui permette l'assemblage d'objets micro- ou nanométriques uniques à des endroits bien définis d'une surface solide de façon simple, fiable, bas-coût et parallèle. Pour ce développement, nous nous sommes intéressés tout particulièrement aux nanoparticules d'Au de 100 nm de diamètre, aux bactéries, puis aux molécules d'ADN. Nous décrirons les stratégies développées reposant sur la lithographie douce puis leurs potentialités pour différentes applications dans les domaines de l'analyse médicale et de la détection.
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Ledoux, Gilles. "Luminescence dans les nano-objets." Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2008. http://tel.archives-ouvertes.fr/tel-00442674.
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Les matériaux lorsqu'ils sont rendus nanométriques montrent des propriétés optiques qui peuvent différer fortement des celles des matériaux à l'état massif. C'est l'étude de ces modifications des propriétés qui a motivé les travaux qui sont présentés dans ce document. Dans une première partie je décris les propriétés de luminescence particulière des nanocristaux de silicium en mettant en évidence un décalage de la luminescence vers le bleu lorsque la taille des nanocristaux diminue et je montre qu'il s'agit d'un phénomène de confinement quantique. Dans le même temps l'importance de la passivation de surface est démontrée. Ces résultats sont ensuite appliqués à la compréhension d'une signature spectrale détectée dans les nuages de poussières inter- et circumstellaires et la fabrication de microcavités luminescente à base de nanocristaux de silicium. Dans une deuxième partie je présente les résultats des études que je mène depuis mon arrivée au sein du LPCML sur les propriétés de luminescence de nanoparticules d'oxydes dopés terres rares. Nous avons ainsi pu montrer que le confinement quantique peut aussi être mis en évidence pour ces matériaux fortement ionique même si l'effet est bien moindre que pour les semi conducteurs. De même on montre que la surface joue un rôle essentiel soit en donnant lieu à de nouvelles émissions soit en créant des défauts tueurs de la luminescence. La taille des nanoparticules modifie aussi la densité d'états de phonons ce qui modifie les populations dans les différents niveaux d'énergie des ions dopants et donc les rapports d'intensité entre les transitions optiques. Enfin le comportement sous excitation à haute énergie (UV dur et X) montre que les rendements sont fortement affectés pour les petites tailles traduisant l‘impossibilité pour les toutes petites particules de supporter une trop grande densité d'excitation. La dernière partie présente les deux axes que je souhaite développer dans les années à venir à savoir la microscopie confocale jusque dans l'UV dur et l'ablation laser en solution pour la synthèse de nanomatériaux originaux.
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Pack, Andreas. "Current Problems in Nano-Optics." Doctoral thesis, Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200200743.
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Ziel dieser Arbeit war die Berechnung elektromagnetischer Nahfelder, die wesentlich sind für die Charakterisierung von Strukturen im Submikrometerbereich. Diese Aufgabenstellung wurde im Rahmen der klassischen Elektrodynamik unter Vernachlässigung von quantenmechanischen und relativistischen Effekten durchgeführt. Die untersuchten Modellsysteme bestanden aus stückweise homogenen Medien. Eine Beschränkung auf eine harmonische Zeitabhängigkeit der Felder fand nicht statt. Zum Einsatz kamen analytische (Mie-Theorie und deren Erweiterungen), semi-analytische (MMP) und rein numerische Methoden (FDTD). Besonders umfassend wurden die Eigenschaften evaneszenter Wellen untersucht. Entgegen der oft üblichen Vorgehensweise wurden die Beschränkung auf 2-dimensionale Modelle vermieden und Metalle nicht idealisiert als perfekt leitend, sondern realistisch über einen komplexen Brechungsindex bzw. über ein äquivalentes Drude-Modell beschrieben. Nur so ist es möglich die Ausbreitung von surface plasmon polaritons zu modellieren und den Einfluß von Volmenplasmonen zu berücksichtigen. Untersucht wurden periodische und nicht periodische Strukturen aus dielektrischen und metallischen Materialien. Solche Systeme sind nützlich aufgrund der Bildung von photonischen Bandlücken (Dielektrika) und der Realisierung hoher Feldverstärkungen (Metalle). Die erste Eigenschaft kann für die Konstruktion von besonders effektiven Laser und die zweite im Rahmen der oberflächenverstärkten Raman-Streuung angewendet werden. Eine weiterer Schwerpunkt dieser Dissertation war die Analyse nahfeld-optischer Mikroskope (SNOM). Mit solchen Apparaturen kann eine Auflösung jenseits des Abbe-Limit erreicht werden. Untersucht wurden die Abbildungseigenschaften aperturloser Nahfeld-Mikroskope und die Ausbreitung von Femto-Sekunden Pulsen in einem konventionellen SNOM, welches mit einer metallbeschichteten Glasfaser ausgestattet ist. Die zweite Fragestellung ist relevant für die Kombination von hoher räumlicher mit hoher zeitlicher Auflösung.
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König, Daniel. "Nano-mechanischer Einzel-Elektronen-Transistor." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-88213.
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Maung, Rohan. "Micro/nano deformation of agglomerates." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/11823.
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Xiao, Lei. "Nano-electrode materials for electroanalysis." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526413.
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Karunaratne, Dinuka. "Nano-Magnetic Devices for Computation." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4516.
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The continuous scaling down of the metal-oxide-semiconductor field-effect transistor (MOSFET)
has improved the performance of electronic appliances. Unfortunately, it has come to a
stage where further scaling of the MOSFET is no longer possible due to the physical and the
fabrication limitations. This has motivated researchers towards designing and fabricating novel
devices that can replace MOSFET technology. Carbon Nanotube Field-Effect Transistors, Single
Electron Tunneling Junctions, Nano-Magnetic Devices, and Spin Field-Effect Transistors are some
prospective candidates that could replace MOSFET devices. In this dissertation, we have studied
the computational performance of Nano−Magnetic Devices due to their attractive features such
as room temperature operation, high density, robustness towards thermal noise, radiation hardened
nature and low static power dissipation.
In this work, we have established that data can be propagated in a causal fashion from a driver
cell to the driven cells. We have fabricated a ferromagnetic wire architecture and used a magnetic
force microscopy (MFM) tip to provide localized magnetic inputs. This experiment validated two
important phenomena; (1) a clocking field is essential to propagate data and (2) upon removal of the
clocking field data can be propagated according to the input data.
Next, we have fabricated and captured MFM images of a nano-magnetic logic architecture
that has computed the majority of seven binary variables. The architecture was designed by interconnecting
three three-input majority logic gates with ferromagnetic and antiferromagnetic wire
architectures. This seven input majority logic architecture can potentially implement eight different
logic functions that could be configured in real-time. All eight functions could be configured by
three control parameters in real-time (by writing logic one or zero to them).
Even though we observed error-free operations in nano-magnetic logic architectures, it became
clear that we needed better control (write/read/clock) over individual single layer nano-magnetic
devices for successful long-term operation. To address the write/clock/read problems, we designed
and fabricated amultilayer nano-magnetic device. We fabricated and performed a set of experiments
with patterned multilayer stacks of Co/Cu/Ni80Fe20 with a bottom layer having a perpendicular
magnetization to realize neighbor interactions between adjacent top layers of devices. Based on the
MFM images, we conclude that dipolar coupling between the top layers of the neighboring devices
can be exploited to construct three-input majority logic gates, antiferromagnetic and ferromagnetic
wire architectures.
Finally, we have experimentally demonstrated a magnetic system that could be used to solve
quadratic optimization problems that arise in computer vision applications. We have harnessed
the energy minimization nature of a magnetic system to directly solve a quadratic optimization
process. We have fabricated a magnetic system corresponding to a real world image and have
identified salient features with true positive rate more than 85%. These experimental results feature
the potentiality of this unconventional computing method to develop a magnetic processor which
solves such complex problems in few clock cycles.
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Burnett, Gary R. "Structural characterisation of nano-dispersions." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365162.
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Fernando, W. C. P. "FEEP thruster nano-satellite application." Thesis, Cranfield University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409591.
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Goller, Bernhard F. "Reactive nano silicon : mediated processes." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516960.
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In this thesis basic methods for the fabrication and characterisation of several nano-silicon containing systems are presented. Due to their morphology, these systems are highly reactive. Silicon wafers were used to prepare layers of porous silicon via electrochemically etching and micro– and nano– sized silicon powders were chemically etched in order to yield silicon nanoparticles. Dependent on the fabrication, particle size of the nanocrystals and porosity of the assemblies can be tailored over a wide range: mean particle sizes can be between 3 to 20 nm and porosities can be varied from 10 to 90 %. A huge surface area of up to 500m2/g which is in addition, due to the fabrication process, hydrogen terminated, entail the outstanding chemical and photo-chemical properties of nanocrystalline silicon. Both, chemical and photo-chemical properties of silicon nanocrystal structures are investigated. The emphasis lies on optical spectroscopy. The indirect band gap structure of silicon in combination with quantum confinement effects are the origin of the interesting luminescence properties of nano-silicon. The energy transfer process from photo-excited excitons confined in silicon nanocrystals to molecules present in the surrounding ambient, like oxygen or a variety of organic substances, has been studied. Measurements demonstrated that long-living excitons very efficiently transfer their energy to surrounding molecules. The low probability of creating excitons which can persist for a long time, from μs to ms, by a photon and structural properties of porous silicon, or rather its reactive surface, however, seem to be the reason for a low total quantum yield of sensitised excited singlet state oxygen.
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Liff, Shawna M. (Shawna Marie). "Thermomechanics of nano-filled elastomers." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46494.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.<br>Includes bibliographical references.<br>The incorporation of nanoparticles into engineering thermoplastic elastomers affords engineers an opportunity to formulate flexible, tough and multifunctional polymer nanocomposites that potentially rival the most advanced materials in nature. Development of these materials is difficult since thermodynamic and kinetic barriers inhibit the dispersal of inorganic, hydrophilic nanoparticles into inherently hydrophobic polymer matrices. Thermoplastic polyurethanes (TPUs) are particularly attractive nanocomposite matrix materials due to their vast range of potential applications (e.g. in artificial organs, coatings, foams, and active wear), their mechanical versatility, and tunable block-polymeric structure. In this thesis we explore methods for systematically nanoreinforcing such materials by exploiting the microphase structure, differential polarities and multiple thermomechanical phase transitions of the macromolecular blocks that constitute the elastomeric matrix. Using a solvent exchange technique we show that it is possible to preferentially nanoreinforce the hard micro-domains of thermoplastic elastomers with smectic clay nanofillers that have characteristic dimensions similar to the hard segment. The adhesion between the clay and the hard micro-domains coupled with the formation of a percolative network not only stiffens and toughens, but increases the heat distortion temperature (HDT) of the material. The discotic clay platelets induce morphological ordering over a range of length scales that results in significant thermomechanical enhancement and expands high temperature applications. This thesis seeks to further enhance the understanding and utility of thermoplastic polyurethane nanocomposites by answering two questions: (1) what thermo-physical interactions between nano-clay and elastomeric thermoplastic polyurethane are taking place? and (2) how can these thermo-physical interactions be exploited?<br>(cont.) To answer these questions the nano-reinforced-hard micro-domain morphology was monitored during deformation using in-situ wide angle x-ray scattering and combined with the results of extensive quasi-static mechanical testing which enabled the identification two characteristic relaxation times. A one-dimensional constitutive model to account for such morphological changes augmenting the previous model for unfilled polyurethanes developed by Qi and Boyce (2005) is discussed. Finally, the thermo-mechanical influence of nano-clay fillers on the shape memory effects exhibited by polyurethane nanocomposites is examined and multi-responsive shape memory polyurethane fibrous mats are developed via electrospinning. Quantifying and controlling the thermo-physical interactions between a block-copolymer with polar segments (e.g. thermoplastic polyurethane) and inorganic nanoparticles (e.g. nano-clay) is important for future nanocomposite processing strategies: the efficacy of nanoreinforcement hinges upon the close matching of characteristic length scale and the adhesion of the nanoparticles to the targeted polymer phase morphology. Exploiting the different polarity of the blocks in conjunction with solvent exchange approach developed in this thesis and solution processing techniques such as electro-spinning, offers an avenue toward the development of high performance, hierarchically-ordered materials that rival natural materials.<br>by Shawna M. Liff.<br>Ph.D.
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Van, der Laak Nicole Kathleen. "Nano-modified InGaN quantum wells." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612841.
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Meenashi, Sundaram Vijay. "Direct Nano-Patterning With Nano-Optic Devices." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7927.
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In this study nano-patterning was carried out using two different nano-optic devices namely- the NSOM and Fresnel zone plate. In the first study, NSOM was used to generate nano-patterns on selected semiconducting (Si and Ge) and metallic (Cr, Cu and Ag) targets under different laser pulse durations, laser energies and number of laser pulses. Based on the experimental results, femtosecond laser pulses, provided lower pattern generation thresholds on targets but higher damage thresholds to the NSOM probes at the wavelength (~400-410 nm) studied, compared with nanosecond laser pulses. Three different mechanisms were identified as the dominant processes for pattern generation under different conditions, namely nano-scale laser ablation, nano-scale thermal oxidation and nano-scale melting/recrystallization of the targets. Furthermore, the resulting nano-patterns also showed a significant dependence on the optical properties (i.e., absorption coefficient and surface reflectivity) of the target material. By comparing the obtained experimental results, it was concluded that the optical energy transport from the NSOM probe to the target dominates the pattern generation when femtosecond laser is applied to the NSOM system. When nanosecond laser is applied, both the thermal and optical energy transported from the NSOM probe to the targets attribute to the obtained morphology of nano-patterns on different targets under the experimental conditions studied. In the second study, a traditional Fresnel zone plate with a focus length of 3 micrometres was fabricated with a novel lift-off process in e-beam lithography. The fabrication process involved, using a HSQ/PMMA bi-layer in a negative tone lift-off process with a layer of conducting polyaniline for charge dissipation. HSQ was used as the high resolution negative resist for e-beam patterning and the PMMA under-layer was used to enable a HSQ lift-off process. The fabricated Fresnel zone plate was used to generate nano-patterns on a UV sensitive photoresist using nanosecond laser light with lamda~409nm. The smallest pattern sizes generated was close to the diffraction limit. Nano-pattern sizes generated on the photoresist were comparable with a numerically calculated intensity distribution at the focus spot of the designed Fresnel zone plate obtained from Scalar Diffraction Theory.
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Cheng-Ta, Yu. "Nano-Acoustic Wave Synthesizing and 2D Nano-Imaging." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2107200512123000.
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Yu, Cheng-Ta, and 余政達. "Nano-Acoustic Wave Synthesizing and 2D Nano-Imaging." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/78909568772981582386.
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碩士<br>國立臺灣大學<br>光電工程學研究所<br>93<br>We have successfully developed a system to generate arbitrary-waveform nano-acoustic-waves (NAWs) with a piezoelectric InGaN/GaN single quantum well (SQW). Based on an optical coherent control technique, the piezoelectric SQW is regarded as an acoustic waveform synthesizer and acoustic frequency tunability in the sub-terahertz range is realized within only one fixed sample. By utilizing the transient transmission measurement, the detection of generated acoustic frequency varying from 0.1 THz to 0.88 THz has been demonstrated. It is also possible to manipulate the generated acoustic waveform by engineering the optical excitation intensities. This flexible system enabled further studies in nano-ultrasonics.
With NAWs composed of acoustic pulses generated from the piezoelectric SQW, a saturation phenomenon of acoustic generation was observed. The acoustic generation mechanisms, especially Coulomb screening of the piezoelectric field in SQW, were discussed with optical excitation power dependency. At high photo-excited carrier concentrations, the acoustic generation induced by screening of built-in piezoelectric field tends to be saturated. To analyze this phenomenon, a simplified charged-parallel-plate model was introduced and a 1.1 MV/cm built-in piezoelectric field can also be roughly estimated.
By means of transient reflectivity measurement, lifetime of acoustic waves in piezoelectric semiconductors can be estimated. With the generated NAWs propagating along the c-axis of a GaN thin film, the lifetime of the 500 GHz coherent longitudinal-acoustic phonons in GaN was measured to be >420 ps, corresponding to a penetration depth more than 3.4 micron.
In this thesis, we also performed 2-D nano-ultrasonic measurement with NAWs. We adopted a 3-period InGaN/GaN multiple-quantum-well (MQW) as our NAW source for a preliminary ultrasonic study with fixed single acoustic frequency of ~500 GHz. Based on 1-D nano-scan performed by acoustic generation and echo detection, we built a 2D image system for nano-ultrasonics. We took a GaN thin-layer etched with a striped pattern on the top surface for nano-ultrasonic demonstration. A 2D surface profile was clearly measured and an etching depth of ~35 nm can be resolved, which was in great agreement with the measurement of a commercial AFM. To make sure of the lateral resolution restricted by the spot size of NAWs, a resolving distance between two acoustic spots was measured to be ~190 nm in our system.