Дисертації з теми "Nanoscale materials and structure"
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ADAMO, FABRIZIO CORRADO. "Nanoscale Structure of Advanced Soft Materials for Innovative Applications." Doctoral thesis, Università Politecnica delle Marche, 2020. http://hdl.handle.net/11566/274538.
Повний текст джерелаMy Ph.D. research work was focused on the investigation of new soft materials, in particular new liquid crystals, polymers and biosystems, of potential interest for innovative applications in the fields of nano- and bio-technologies including novel electronic and photonic devices, high mechanical-performance materials, biomaterials for nanomedicine and biosensing. The main purpose of my research work was the study of the relationships between the peculiar macroscopic properties of these materials and their structure at the nanoscale. To this end, a key role was played by the X-ray diffraction and scattering techniques used as the primary tool of experimental investigation. The X-ray measurements were carried out at the synchrotron light sources of the European Synchrotron Radiation Facility, Grenoble (France), ELETTRA, Trieste (Italy), and ALBA, Barcelona (Spain), in the context of officially approved experiments. A series of complementary techniques were also employed to better characterize these materials, in collaboration with other international research groups. The research work can be identified with four main topics: i) the influence of the molecular structure on the nematic phase of bent-core liquid crystals. The recently discovered cybotactic nanostructure of their nematic phase makes them the ideal candidates for the two most sought after and elusive properties of liquid crystals, namely the nematic biaxiality and the nematic ferroelectricity, widely recognized as the Holy Grail of the liquid crystal science. The findings suggest useful clues to guide the research effort towards the synthesis of novel bent-core mesogens exhibiting such features; ii) the study of the nanostructure and molecular ordering of ultra-thin films of bent-core mesogens deposited on solid substrate to gain insight into the mechanisms of anchoring and self-assembling of liquid crystal molecules at the interface and investigate the molecular space arrangement (in-plane and out-of-plane order). We obtained a highly ordered film with the anisotropic in-plane structure of the liquid crystal molecules, which has never been reported in the literature for these systems; iii) structural study of a reactive thermotropic liquid crystal used in the production of a new class of high-temperature/high-performance thermosets - crosslinked 3D networks designed to preserve the local nematic morphology in the solid state. High-temperature X-ray diffraction studies made it possible for the first time to monitor the transformation of the ethynyl end-group and to follow the evolution of the nematic phase during the chain extension/cross-linking reactions; iv) the structural and physico-chemical characterization of novel lyotropic liquid crystalline nanosystems for their potential applications in the development of efficient and biocompatible vectors for drug delivery in nanomedicine. The study was focused on the incorporation of a cationic surfactant in the phytantriol cubic phase, unloaded and loaded with the anticancer drug 5-fluorouracil. The study evidences the efficiency of the phytantriol/ionic surfactant system as anticancer drug delivery vectors.
Kuna, Jeffrey James. "The effect of nanoscale structure on interfacial energy." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/62744.
Повний текст джерелаVita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Interfaces are ubiquitous in nature. From solidification fronts to the surfaces of biological cells, interfacial properties determine the interactions between a solid and a liquid. Interfaces, specifically liquid-solid interfaces, play important roles in many fields of science. In the field of biology, interfaces are fundamental in determining cell-cell interactions, protein folding behavior and assembly, and ligand binding. In chemistry, heterogeneous catalysts greatly increase reaction rates of reactions occurring at the interface. In materials science, crystallization and the resulting crystal habit are determined by interfacial properties, and interfaces affect diffusion through polycrystalline materials. In nanotechnology, much work on self-assembly, molecular recognition, catalysis, electrochemistry and numerous other applications depends on the properties of interfaces. The structure and properties of interfaces have been studied experimentally using a variety of techniques including various forms of microscopy, wetting measurements, and scattering techniques. Conventionally, the typical interface considered was highly homogeneous and exhibited a uniform composition and roughness. In contrast, many of the interfaces encountered in biological or nanotechnological systems have surfaces with a greater degree of complexity. While the surface may be compositionally homogeneous over a large area, these surfaces are structured and have a complex surface topology. On a mixed interface, several different chemical groups may be present on the surface, and the chemical composition can vary on a sub-nanometer length scale. Structured systems are inherently difficult to experimentally measure. Most techniques available to characterize interfaces average properties over the entire surface and are not sensitive to nanoscale variations. Furthermore, many of these techniques are incapable of distinguishing global, surface-dependent properties from artifactual influences. Many surface characterization techniques require a large, flat, smooth surface. Preparation of mixed interfaces is an experimental challenge as well as many mixed interfaces with nanoscale structure are present on objects that are themselves nanoscale, such as proteins. Several technological hurdles exist that limit the ability to produce nanoscale mixed interfaces large enough for conventional measurements. In this thesis, the effect of surface structure on wetting behavior was investigated. Interfaces can be characterized by the energy required to form them, a quantity called interfacial energy. Models have been developed to describe the interfacial energy of mixed interfaces for a wide range of surfaces. These models only account for the composition of the surface. The wetting behavior of mixed surfaces has also been related to artifact-dependent wetting effects (namely the effect of a boundary or asperity). No attempt has been made to incorporate surface structure into a global expression of interfacial energy. This thesis will study how the structure of an interface determines the resulting interfacial energy. Surfaces prepared with chemical domains of different length scales demonstrate and interfacial energy trend with significant deviation from the current best model. Specifically, the observed trend is non-linear, unlike the conventional model, and furthermore in some cases, is non-monotonic. These deviations are shown to stem from the surfaces' intrinsic structure and are not an artifact of the measurement process or surface defects. The deviations from the predicted trend are explained by the molecular scale structure of the solvent. The two proposed mechanisms, cavitation and confinement, arise when surface features are smaller than a solvent-dependent length. With cavitation, nonwetting surface features below a size threshold are more wetting than would be expected. With confinement, wetting patches become less wetting as their dimensions are decreased. Molecular dynamics simulations support the proposed mechanisms. Additional experimental results provide further experimental evidence of the proposed molecular-scale wetting phenomena.
by Jeffrey James Kuna.
Ph.D.
Ma, Fengxian. "Computational exploration of structure and electronic functionality in nanoscale materials." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/112361/1/Fengxian_Ma_Thesis.pdf.
Повний текст джерелаJanko, Marek. "Structure and stability of biological materials – characterisation at the nanoscale." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-143453.
Повний текст джерелаTuchband, Michael R. "Revealing the Nanoscale Structure and Behavior of the Twist-Bend Nematic Liquid Crystal Phase." Thesis, University of Colorado at Boulder, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10752109.
Повний текст джерелаThe nematic phases of liquid crystals have been the most thoroughly investigated since the founding of the liquid crystal field in the early 1900’s. The resulting technologies, most notably the liquid crystal display, have changed our world and spawned an entire industry. Consequently, the recent identification of a new type of nematic – the twist-bend nematic – was met with as much surprise as excitement, as it melds the fluid properties and environmental responsiveness of conventional nematics with the intrinsic polarization and complex ordering of bent-core liquid crystals. I summarize the history of the twist-bend nematic phase, charting the development of our understanding from its first identification to the present day. Furthermore, I enumerate and highlight my own efforts in the field to characterize the behavior and nanoscale organization of the twist-bend phase.
Ehrlich, Deborah J. C. "Synthetic strategies for control of structure from individual macromolecules to nanoscale materials to networks." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122451.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references.
Chapter 1. Aqueous self-assembly of prodrug macromonomers. A series of highly tunable micelles for drug delivery were made from norbornene based poly(ethylene glycol) macromonomers with covalently linked drugs. A total of five macromonomers were made using three different drugs (telmisartan, paclitaxel, and SN-38) and three different drug loadings. Combinations of these macromonomers were then allowed to self assemble into micellar aggregates. The size, stability, and shape of these micellar aggregates were controlled with the highly versatile structure. Chapter 2. Post micellization modification of norbornene-containing prodrug macromonomers. Highly tunable micelles for drug delivery were functionalized after their selfassembly. Post-micellization inverse electron demand Diels-Alder reactions of norbornenes and tetrazines were used to signal changes in micelle size and stability through the addition of either hydrophilic or hydrophobic tetrazines.
Thiol-ene additions reactions were used to increase micelle size and form chemically crosslinked nanoparticles. These modifications of norbornene-containing prodrug macromonomer assemblies illustrate their versatility. Chapter 3. Synthesis of polymers by iterative exponential growth. A scalable synthetic route that enables absolute control over polymer sequence and structure has remained a key challenge in polymer chemistry. Here, we report an iterative exponential growth plus side-chain functionalization (IEG+) strategy for the production of macromolecules with defined sequence, length, and stereoconfiguration. Each IEG+ cycle begins with the azide opening of an enantiopure epoxide, followed by side chain functionalization, alkyne deprotection, and copper-catalyzed azide-alkyne cycloaddition (CuAAC). These cycles have been conducted to form unimolecular macromolecules with molar masses of over 6,000 g/mol.
Subsequent modifications to IEG+ allow for the functionalization of monomers prior to the IEG+ cycle, expanding the library of compatible side chain chemistries. Chapter 4. Introduction to elastomer toughening strategies. Silicone elastomers are ubiquitous. Here, silicone elastomers are discussed in terms of network structure, the impact of network structure upon physical properties, and modifications of network structure in order to achieve desired physical properties. Fillers, the standard toughening strategy, are discussed in conjunction with entanglement density. Focus is placed on the impact of entanglement density on material properties. Topological networks are discussed and noted for their stress dissipative properties. Chapter 5. Topology modification of polydimethylsiloxane elastomers through loop formation. Topological networks are well known for their stress dissipation through the pulley effect leading to soft, extensible materials.
Combining these properties with a traditionally crosslinked network to produce a hybrid material allows for enhanced extensibility without a loss in modulus. Here, such hybrid networks were made with poly(dimethyl siloxane) polymers of a range of molecular weights. Side-loop polymer brushes were synthesized and then crosslinked to create hybrid networks with the statistical formation of topological bonds. These materials were characterized through tensile testing. Elastomers formed with the same molecular weight polymer in both side-loops and network formation did not show mechanical properties that depended upon the fraction of networks used for brush formation. Elastomers made with long polymers in brush formation and shorter polymers for network formation resulted in highly extensible systems without significant loss in modulus.
by Deborah J.C. Ehrlich.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemistry
Salahshoor, Pirsoltan Hossein. "Nanoscale structure and mechanical properties of a Soft Material." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/924.
Повний текст джерелаJanko, Marek [Verfasser], and Robert [Akademischer Betreuer] Stark. "Structure and stability of biological materials – characterisation at the nanoscale / Marek Janko. Betreuer: Robert Stark." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1022791176/34.
Повний текст джерелаHatton, Hilary J. "Magnetic and structural studies of nanoscale multilayer and granular alloy systems of Ag and FeCo." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286916.
Повний текст джерелаSchiffrin, Agustin. "Self-assembly of amino acids on noble metal surfaces : morphological, chemical and electronic control of matter at the nanoscale." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/798.
Повний текст джерелаЗленко, Віталій Олександрович, Виталий Александрович Зленко, Vitalii Oleksandrovych Zlenko, Михайло Валерійович Каверін, Михаил Валерьевич Каверин та Mykhailo Valeriiovych Kaverin. "Апаратно-програмний комплекс дослідження терморезистивних властивостей тонких плівок". Thesis, Вид-во СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/3986.
Повний текст джерелаМетою нашої роботи було створення автоматизованої системи управління науковим експериментом для дослідження терморизестивних властивостей плівкових матеріалів. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/3986
Ohmura, Jacqueline (Jacqueline Frances). "Utilizing viruses to probe the material process - structure - property relationship : controlling catalytic properties via protein engineering and nanoscale synthesis." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115761.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 136-146).
From the fabrication of fine chemicals, to the increasing attainability of a non-petrochemical based energy infrastructure, catalysts play an important role in meeting the increasing energy and consumable demands of today without compromising the global health of tomorrow. Development of these catalysts relies on the fundamental understanding of the effects individual catalyst properties have on catalytic function. Unfortunately, control, and therefore deconvolution of individual parameter effects, can be quite challenging. Due to the nanoscale formfactor and wide range of available surface chemistries, biological catalyst fabrication affords one solution to this challenge. To this end, this work details the processing of M13 bacteriophage as a synthetic toolbox to modulate key catalyst parameters to elucidate the relationship between catalyst structure and performance. With respect to electrocatalysis, a biotemplating method for the development of tunable 3D nanofoams is detailed. Viral templates were rationally assembled into a variety of genetically programmable architectures and subsequently templated into a variety of material compositions. Subsequently, this synthetic method was employed to examine the effects of nanostructure on electro-catalytic activity. Next, nanoparticle driven heterogeneous catalysis was targeted. Nanoparticle-protein binding affinities were leveraged to explore the relationship between nanoparticles and their supports to identify a selective, base free alcohol oxidation catalyst. Finally, the surface proteins of the M13 virus were modified to mirror homogeneous copper-ligand chemistries. These viruses displayed binding pocket free copper complexation and catalytic efficacy in addition to recyclability and solvent robustness. Subsequently, the multiple functional handles of the viron were utilized to create catalytic ensembles of varying ratios. Single and dendrimeric TEMPO (4-Carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl) were chemically conjugated to the surface of several catalytically active phage clones further tailoring catalytic function. Taken together, these studies provide strong evidence of the utility of biologically fabricated materials for catalytic design.
by Jacqueline Ohmura.
Ph. D.
Leininger, Wyatt Christopher. "Design and Control of a Micro/Nano Load Stage for In-Situ AFM Observation and Nanoscale Structural and Mechanical Characterization of MWCNT-Epoxy Composites." Thesis, North Dakota State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10680380.
Повний текст джерелаNanomaterial composites hold improvement potential for many materials. Improvements arise through known material behaviors and unique nanoscale effects to improve performance in areas including elastic modulus and damping as well as various processes, and products. Review of research spurred development of a load-stage. The load stage could be used independently, or in conjunction with an AFM to investigate bulk and nanoscale material mechanics.
The effect of MWCNT content on structural damping, elastic modulus, toughness, loss modulus, and glass transition temperature was investigated using the load stage, AMF, and DMA. Initial investigation showed elastic modulus increased 23% with 1wt.% MWCNT versus pure epoxy and in-situ imaging observed micro/nanoscale deformation.
Dynamic capabilities of the load stage were investigated as a method to achieve higher stress than available through DMA. The system showed energy dissipation across all reinforce levels, with ~480% peak for the 1wt.% MWCNT material vs. the neat epoxy at 1Hz.
Leininger, Wyatt C. "Design and Control of a Micro/Nano Load Stage for In-Situ AFM Observation and Nanoscale Structural and Mechanical Characterization of MWCNT-Epoxy Composites." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28190.
Повний текст джерелаND NASA EPSCoR FAR0017788
NDSU Development Foundation FAR0017503
National Science Foundation (NSF) Grant# HRD-0811239 to the NDSU Advance FORWARD Program
Gao, Hantian. "Nanoscale Characterization and Control of Native Point Defects in Metal Oxide Semiconductors and Device Structures." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618838504594148.
Повний текст джерелаCasalena, Lee. "Multimodal Nanoscale Characterization of Transformation and Deformation Mechanisms in Several Nickel Titanium Based Shape Memory Alloys." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1499568013015563.
Повний текст джерелаAlmahmoud, Khaled Hasan Musa. "Thermal Transport Modeling in Three-Dimensional Pillared Graphene Structures for Efficient Heat Removal." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1752407/.
Повний текст джерелаNilwala, Gamaralalage Premasiri Kasun Viraj Madusanka. "Electron Transport in Chalcogenide Nanostructures." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1572259784431038.
Повний текст джерелаChoi, Fung Sing. "Nanoscale electrical characterisation of nitride structures." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283496.
Повний текст джерелаAili, Daniel. "Polypeptide-Based Nanoscale Materials." Doctoral thesis, Linköpings universitet, Sensorvetenskap och Molekylfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15124.
Повний текст джерелаIngenjörer och vetenskapsmän har ofta inspirerats av naturen i sökandet efter lösningar på tekniska problem. Allt ifrån byggnadskonstruktioner, flygplansvingar, kompositmaterial till kardborrebandet har skapats med utgångspunkt från förebilder i naturen. Många av de material och konstruktioner som återfinns i naturen har åtråvärda egenskaper som är svåra att erhålla i syntetiska matrial med traditionell teknik. Även om vi i flera fall kan härma sammansättningen och formen blir resultatet inte nödvändigtvis det samma. Den största skillnaden mellan syntetiska material och material producerade av levande organismer är hur deras komponenter sinsemellan är organiserade och sammansatta. I syntetiska material är komponenterna ofta inbördes mer eller mindre slumpvis ordnade medan de i biologiska material är organiserade med en oerhörd precision som sträcker sig ända ned på molekyl- och atomnivå. Naturens byggstenar har genom evolutionens gång förfinats för att spontant kunna organisera sig och bilda komplexa material och strukturer. Denna process, som styrs genom att många svaga krafter inom och mellan byggstenarna samverkar, kallas ofta för självorganisering och är en förutsättning för allt liv. Självorganisering har också blivit en allt viktigare metod inom nanotekniken för att konstruera material och strukturer med nanometerprecision. I den här avhandlingen beskrivs en typ av självorganiserande material där byggstenarna utgörs av nanometerstora guldpartiklar och syntetiska proteiner. De syntetiska proteinerna är designade för att efterlikna naturliga biomolekyler och antar en välbestämd tredimensionell struktur när två av dem interagerar med varandra. Denna interaktion är mycket specifik men kan styras genom att variera kemiska parametrar som surhet och jonstyrka vilket ger en möjlighet att påverka och kontrollera proteinernas struktur. Proteinerna har vidare modifierats för att spontant organisera sig till fibrer som är flera mikrometer långa men endast några nanometer tjocka. Proteinfibrer utgör en mycket viktig typ av strukturer i biologiska system och finns i alltifrån spindelväv till muskler. Syntetiska proteinfibrer är därför både ett intressant modellsystem och ett material med många potentiellt intressanta användningsområden. Genom att fästa de syntetiska proteinerna på ytan av guldnanopartiklar går interaktionerna mellan partiklarna att kontrollera på samma sätt som interaktionerna mellan proteinerna. Krafterna mellan proteinerna och interaktionerna involverade i proteinernas veckning har använts för att reversibelt aggregera och organisera nanopartiklarna. Ett antal olika byggstenar har studerats och utvecklats till något som liknar ett mycket enkelt nano-Lego, som på en given signal spontant bygger ihop sig eller trillar isär. Guldnanopartiklar är intressanta eftersom de är stabila och lätta att modifiera kemiskt men också på grund av deras optiska egenskaper som ger dem en ovanligt vacker vinröd färg. Färgen uppstår på grund av partiklarnas ringa storlek och varierar naturligt med egenskaperna hos den omgivande miljön. Detta gör det enkelt att studera hur partiklarna interagerar eftersom de byter färg när de närmar sig varandra, men gör dem också intressanta för sensortillämpningar. En enkel och robust sensor beskrivs i avhandlingen där syntetiska proteiner, speciellt utformade för att upptäcka och binda andra molekyler, har fästs på nanopartiklarna. Med partiklarnas hjälp går det att med blotta ögat detektera ett mänskligt protein i koncentrationer under ett tusendels gram per liter. En tidig diagnos av sjukdomstillstånd kan i de flesta fall avsevärt underlätta behandlingen och behovet av enkla sensorer för att bestämma närvaro och koncentration av medicinskt intressanta molekyler är därför mycket stort.
Duzhko, Volodimyr. "Photovoltage phenomena in nanoscale materials." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964920964.
Повний текст джерелаSattar, Abdul. "Electrical Characterization of Cluster Devices." Thesis, University of Canterbury. Physics and Astronomy, 2011. http://hdl.handle.net/10092/6677.
Повний текст джерелаKim, Sung-gi. "PET Nanocomposites Development with Nanoscale Materials." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1178043237.
Повний текст джерелаTypescript. "Submitted as partial fulfillment of the requirements for The Doctor of Philosophy Degree in Engineering." Bibliography: leaves 200-205.
Wang, Jinfeng. "Characterization and synthesis of nanoscale materials." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/JinfengWang_09007dcc80564540.pdf.
Повний текст джерелаVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed August 28, 2008) Thesis completed as part of a cooperative degree program with Missouri University of Science & Technology and the University of Missouri--St. Louis. Includes bibliographical references (p. 129-142).
Raanaei, Hossein. "Tailoring Properties of Materials at the Nanoscale." Doctoral thesis, Uppsala : Uppsala University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-107425.
Повний текст джерелаWang, Wentai. "Synthesis and Applications of Nanoscale Carbon Materials." Thesis, Griffith University, 2015. http://hdl.handle.net/10072/366678.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Pierre, Le Brun Anton. "Nanoscale structure of membrane protein arrays." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500907.
Повний текст джерелаGangmei, Prim. "Magnetisation dynamics of nanoscale magnetic materials and spintronics." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3502.
Повний текст джерелаDougan, Jennifer Anne. "Modified oligonucleotides for the functionalisation of nanoscale materials." Thesis, University of Strathclyde, 2009. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=14361.
Повний текст джерелаLi, Mei. "Synthesis, organization and characterization of nanoscale inorganic materials." Thesis, University of Bristol, 2000. http://hdl.handle.net/1983/9838d282-a46c-4e5b-b61d-6f4a883bc632.
Повний текст джерелаIhalawela, Chandrasiri A. "Sb-Te Phase-change Materials under Nanoscale Confinement." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1449245846.
Повний текст джерелаWolf, Daniel, and Christian Kübel. "Electron Tomography for 3D imaging of Nanoscale Materials." Carl Hanser Verlag, 2018. https://slub.qucosa.de/id/qucosa%3A33863.
Повний текст джерелаBalakishan, Harishankar. "Nanoscale Tomography Based in Electrostatic Force Microscopy." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/671789.
Повний текст джерелаLa capacidad de caracterizar los elementos debajo de la superficie ha sido una necesidad imperiosa en los campos de la ciencia de los materiales, la tecnología de polímeros, la biología y las ciencias médicas. La microscopía de sonda de barrido (SPM por sus siglas en inglés) es una técnica de microscopía que permite exploran la superficie de una muestra a nano escala utilizando una sonda nanométrica, donde los datos adquiridos se utilizan para reconstruir las propiedades físicas de las muestras en resolución nanométrica (por ejemplo, topografía). Dado que las mediciones se pueden realizar sin contacto, los diferentes tipos de SPM se han convertido en candidatos óptimos para el estudio de propiedades sin necesidad de destruir la muestra. El SPM también posee la ventaja relativa de ser no invasivo, no destructivo, requiere una preparación de muestra relativamente sencilla, puede extenderse a cualquier ambiente (inerte, vacío ambiental), y también medirse en aire, agua o cualquier medio biológico. Entre ellos, la microscopía de fuerza electrostática, se ha utilizado con éxito en investigaciones del subsuelo para estudiar las modificaciones de composición debajo de las capas orgánicas, obtener imágenes debajo de las capas orgánicas, obtener imágenes de moléculas de agua confinada en canales nanométricos, imágenes de nanotubos de carbono, redes de grafeno y nanopartículas dentro de polímeros. Los nanocompuestos, que consisten en nanoestructuras en gran parte de su matriz para mejorar la eficiencia de la matriz, han sido una de las aplicaciones de la ciencia de materiales incorporadas con éxito en las últimas dos décadas. Las nanopartículas de plata tienen especialmente un aluvión de aplicaciones en su haber que van desde aplicaciones de células solares, pantallas táctiles, LED hasta dispositivos portátiles flexibles. Comprender las características del subsuelo o la tomografía de estos nanocompuestos podría ayudarnos a comprender sus propiedades, interpretándolas en función de su dependencia paramétrica, lo que luego nos ayudaría a ajustarlos para otras aplicaciones. En esta tesis, se han realizado estudios computacionales individuales de nano cables enterrados en una matriz dieléctrica para observar los efectos de varios parámetros que influyen en las imágenes del subsuelo. La resolución espacial tiene una importancia primordial, ya que se estudia su comportamiento de dos nano cables paralelos junto con dos nano cables superpuestos uno encima del otro. Además, el análisis de nanocompuestos de nano cables de plata se han investigado con la ayuda de la microscopía de barrido volumen de fuerza dieléctrica, una técnica propuesta recientemente con el EFM. La mayor parte de la matriz está compuesta de gelatina que puede ofrecer un rango de permitividades dependiendo del grado de hidratación, por ejemplo, aquí εr ~ 5 a εr ~ 14. Esta muestra se analiza experimentalmente, se obtienen imágenes y la profundidad de los nano cables en la matriz se mapean con el análisis teórico. Esta tesis nos proporciona nueva información y técnicas avanzadas a nivel tomográfico que ayudaran a la realización de imágenes de nanoestructuras de nuevos nanomateriales para aplicaciones en Salud y Electrónica.
Roigé, Godia Abel. "Nanoscale spatially-resolved characterization of photovoltaic devices and materials." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/287990.
Повний текст джерелаPhotovoltaic (PV) technology has experienced a tremendous growth during recent years, and PV energy is expected to be one of the main energy sources in the future. This growth has been induced by a drastic reduction of production costs, and an important evolution of solar cell technology that has lead to an increase of solar cells efficiency. In the context of device evolution, material and device characterization becomes an important task to further explore novel PV systems and architectures. Since ultimate PV technologies progressively move towards thinner devices and smaller structures, characterization techniques with high spatial resolution play an important role for the further technological development of the PV field. In this work, we apply different high-resolution advanced characterization techniques such as Kelvin Probe Force Microscopy (KPFM), micro-Raman and micro-Photoluminescence (PL) to carry out a comprehensive study of crystalline silicon (c-Si) PV devices. In particular, the work is focused on the analysis of rear surface passivation layers and local base contacts processed by laser, which are key features of ultimate c-Si PV architectures. The high-resolution capabilities of such experimental techniques allow obtaining unique and exclusive information about material properties and device operation. In this sense, the obtained information represents the foundations to improve and optimize the current PV devices and technology. In the final part of the work, we apply the same experimental techniques to study the molecular distribution across organic PV (OPV) thin films. OPV systems show attractive properties like low cost and flexibility, which make them suitable candidates for a broad range of novel application possibilities. With this last study we intend to demonstrate the versatility and applicability of the used characterization techniques for studying a wide range of PV materials and devices.
Wittborn, Jesper. "Nanoscale studies of functional materials using scanning probe microscopy." Doctoral thesis, KTH, Materials Science and Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3000.
Повний текст джерелаThis thesis deals with developing suitable modifications ofScanning Probe Microscopy (SPM) for investigations offunctional properties of materials. In order to make itpossible to investigate a number of properties of variousfunctional systemsusing SPM the following new techniques have beendeveloped:
A magnetic force microscope (MFM) having capability ofboth dc- and ac-mode detection.
A method to extract switching field distributions fromseries of MFM images.
A novel technique for magnetic microscopy using anon-magnetic probe to investigate the magnetostrictiveresponse of ferromagnetic materials, capable of 1 nmresolution.
A technique to determine the magnetostriction at lowexternal fields using AFM.
A technique for AFM studies of ferroelectric domainsusing the inverse piezoelectric effect of ferroelectricmaterials.
A technique for studying the relative stiffnessdistribution in composite materials using AFM.
Scanning friction microscopy.
Methods for determining the structure ofnanoindents.
Using the techniques highlighted above, we have studiedfunctional materials of current interest from bothtechnological and basic research points of view. Some of the materials and the main results obtainedare:
The role of magnetism arising from chains of nano-sizedmagnetite particles bio-mineralized in magneto-tacticbacteria is a topic of growing interest today. We use MFMtechniques to investigate magnetic flux reversal phenomena insuch chains. It is found that:
1.2.It is noteworthy that from our MFM measurements on singlemagnetosomes of 50 nm we havedetected magnetic moments as small as 3.1·10-14emu. Such detection is not possible by anyother technique known today.
1.2.
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It is noteworthy that from our MFM measurements on singlemagnetosomes of 50 nm we havedetected magnetic moments as small as 3.1·10-14emu. Such detection is not possible by anyother technique known today.
Evaluation of magnetostrictive properties of smallstructures is extremely important and relevant to informationstorage media and read/write heads, in particular, as storagedensities beyond 30 gigabytes is pursued. In this thesis astudy of domain wall width of submicron man-made Co dots ispresented with a newly developed magnetostrictive imagingtechnique. Domain wall width of ~35 nm have been observed inmagnetic dots of 250 nm diameter. Additionally, we found thatdue to magnetostatic coupling the dots influence theneighboring domains to align ferromagnetically. The studiespresented herein are the first such to be reported inliterature.
From an investigation of epitaxially grown ferroelectricPbZr0.65Ti0.35O3(PZT) thin films the existence of orderedpolydomain configurations in grains larger than 200 nm aredemonstrated.
For an understanding of the interaction between thecomponents of composite materials the relative stiffness wasdetermined for a composite material consisting of TiNinclusions in an Al2O3matrix. This would be a new approach to studythe local mechanical properties of future nano-compositematerials.
Preliminary investigations of the structure of nanoindentson a variety of materials demonstrate potentially richpossibilities to study the hardness at various depths inadvanced nanostructured materials
Hooton, Jennifer Claire. "The nanoscale characterization and interparticulate interactions of pharmaceutical materials." Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/10047/.
Повний текст джерелаLiao, Bolin Ph D. Massachusetts Institute of Technology. "Nanoscale electron, phonon and spin transport in thermoelectric materials." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104231.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 133-146).
Climate change is among the most critical challenges that are facing the human race in the 21st century. One of the major factors that leads to climate change is the increasing consumption of fossil fuels, driven by industrialization and economic growth at an unprecedented pace. For a secure and sustainable future of energy and the environment, new clean and efficient energy technologies are in urgent need. Thermoelectric materials are a group of materials that can directly convert heat into electricity. Being solid state, clean, reliable and without moving parts, thermoelectric energy conversion holds great promise as a candidate technology to harvest energy from thermal sources, such as the sun and terrestrial heat sources, as well as improve the efficiency of existing energy systems by recycling the inevitable waste heat. The bottleneck that prevents large-scale deployment of thermoelectric modules so far, however, is the relatively low efficiency and high cost. A good thermoelectric material needs to conduct electricity well and conduct heat poorly to attain high efficiency. Remarkable progress has been made in the past decade to decouple the charge and heat transport and thus improve the material performance. Most of the progress has been based on a more detailed understanding of the transport and interaction of fundamental energy carriers, such as electrons and phonons in most semiconductors, and magnons in magnetic materials. These understandings have been achieved through the development of both first-principles simulations and experimental spectroscopic tools, in particular for phonon transport and phonon-phonon interaction, which have enabled calculations and measurements at the single-phonon-mode level. Information gained from these studies formed the foundation of the successful engineering efforts of designing nanostructured thermoelectric materials. Although the nanostructuring approach has been able to reduce the thermal conductivity of thermoelectric materials down to proximity of the amorphous limit, it has been realized by the community that further improvement of thermoelectric materials requires breakthroughs in boosting the electrical transport properties, including the electrical conductivity and the Seebeck coefficient. Despite several existing strategies, a prerequisite for systematic improvement is, again, insight into the transport and interaction of fundamental carriers, particularly involving electrons, at the single-mode level. This insight has largely remained lacking in terms of electrons, both on the simulation side and on the experimental side. This thesis aims to develop both simulation and experimental tools to study nanoscale electron, phonon and magnon transport and their interactions, with a particular emphasis on understanding the electron-phonon interaction at the single-mode level. This is among the most important forms of carrier interactions and determines the intrinsic electron transport properties of most conductors. Regarding phonon transport, we applied first-principles lattice dynamics to study phonon-phonon interaction and lattice thermal conductivity in a strongly-correlated thermoelectric compound FeSb 2. On electronphonon interactions, we studied from first-principles the intrinsic electrical transport properties of phosphorene, which are limited by electron-phonon interactions, analyzed its anisotropy and evaluated its potential as a thermoelectric material; we studied how free carriers can in turn scatter phonons through the electron-phonon interaction and reduce the lattice thermal conductivity; to verify this finding, we designed an ultrafast photoacoustic spectroscopic technique to directly detect the damping of a single phonon mode due to electron-phonon interaction. On phonon-magnon interactions, we applied the coupled Boltzmann equation to analyze coupled phonon-magnon diffusion and proposed a novel magnon cooling effect. These fundamental discoveries can potentially lead to new design principles for more efficient thermoelectric materials in the future.
by Bolin Liao.
Ph. D.
Che, Rose Laili. "Exploiting nanoscale materials properties for controlled drug delivery systems." Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/47950/.
Повний текст джерелаChauhan, Vinay Singh. "Impact of Nanoscale Defects on Thermal Transport in Materials." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586440154974469.
Повний текст джерелаScott, William Walter Jr. "Micro/Nanoscale Differential Wear and Corrosion of Multiphase Materials." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu994420446.
Повний текст джерелаIncorvia, Jean Anne Currivan. "Nanoscale Magnetic Materials for Energy-Efficient Spin Based Transistors." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467318.
Повний текст джерелаPhysics
Scott, William Walter. "Micro/nanoscale differential wear and corrosion of multiphase materials /." Connect to this title online, 2001. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu994420446.
Повний текст джерелаAdvisor: Bharat Bhushan, Dept. of Mechanical Engineering. Includes bibliographical references (leaves 145-152). Available online vai OhioLINK's ETD center.
Yen, Chun-Wan. "Plasmonic photochemistry on the nanoscale." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41085.
Повний текст джерелаTian, Zhiting. "Nanoscale heat transfer in argon-like solids via molecular dynamics simuations." Diss., Online access via UMI:, 2009.
Знайти повний текст джерелаIncludes bibliographical references.
Ritchie, Kenneth Patrick. "Probing nanoscale adhesion and structure at soft interfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34615.pdf.
Повний текст джерелаEvans, Matthew Hiram. "Nanoscale structure and transport : from atoms to devices." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32297.
Повний текст джерелаIncludes bibliographical references (p. 145-159).
Nanoscale structures present both unique physics and unique theoretical challenges. Atomic-scale simulations can find novel nanostructures with desirable properties, but the search can be difficult if the wide range of possible structures is not well understood. Electrical response and other non-equilibrium transport phenomena are measured experimentally, but not always simulated accurately. This thesis presents four diverse applications that demonstrate how first-principles calculations can address these challenges. Novel boron nanotube structures with unusual elastic properties are presented. Internal degrees of freedom are identified that allow longitudinal stress to be dissipated without changing the tube's diameter, leading to high lateral stiffness. Self-trapped hole structures in amorphous silicon dioxide are investigated in order to connect the behavior of hole currents to atomic-scale structures. Calculations on a paired-oxygen analogue to the ... center show that such a configuration does not result in a metastable trapped-hole state. A novel method to enable first-principles mobility calculations in ultrathin silicon-on-insulator (UTSOI) structures is presented and applied to interface roughness scattering in transistor channels. Self-consistent potentials and accurate wavefunctions and band structures allow for a direct link between measured electrical response and atomic structure. Atomic-scale interface roughness is shown to be an important limit on mobility at high carrier densities. At low carrier densities, such short-wavelength roughness results in qualitatively different mobility behavior than gradual UTSOI channel thickness fluctuations.
(cont.) An effective Hamiltonian technique to calculate short-time, non-equilibrium fluctuations in quantum devices is developed. Applications to quantum dots and resonant tunneling diodes show that temporal fluctuations are reproduced well.
by Matthew Hiram Evans.
Ph.D.
Macias, Celia Edith 1982. "Nanoscale properties of poly(ethylene terephthalate) vascular grafts." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32727.
Повний текст джерелаIncludes bibliographical references (leaves 46-48).
Vascular grafts are prosthetic tubes that serve as artificial replacements for damaged blood vessels. Poly(ethylene-terephthalate), PET, has been successfully used in large diameter grafts; however, small caliber grafts are still a major challenge in biomaterials. Due to surface forces, blood plasma proteins adsorb to the graft, resulting in inflammation, infection, thrombus formation, and ultimately, vessel reclosure. The object of this project was to characterize and analyze the nanoscale surface properties of three different commercial vascular grafts, woven collagen-coated, knitted collagen- coated, and knitted heparin-bonded, all PET-based. The study was performed in order to ascertain differences in biocompatibility due to surface coating and morphology. Scanning Electron Microscopy, Atomic Force Microscopy and High Resolution Force Spectroscopy techniques were used to characterize the surface of the samples as well as to measure the forces between these surfaces and blood plasma proteins. The results will serve as a basis for the understanding of the nanoscale interactions between the biomaterial and blood plasma proteins. Such interactions are brought about by the different surface topologies and components, therefore a thorough understanding of surface properties will act as a building block for further changes in small caliber vascular grafts in order to enhance their biocompatibility.
by Celia Edith Macias.
S.B.
Sines, Paul B. "Fabrication of thin film nanoscale alumina templates." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2183.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains vii, 44 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 35-37).
Estradé, Albiol Sònia. "Electron Energy Loss Spectroscopy Solutions for Nanoscale Materials Science Problems." Doctoral thesis, Universitat de Barcelona, 2009. http://hdl.handle.net/10803/662847.
Повний текст джерелаEn el microscopi electrònic de transmissió (TEM), un electró incident sofreix tant xocs elàstics com inelàstics en travessar la mostra prima d’estat sòlid que s’està caracteritzant. En cas de xoc inelàstic, l’electró incident cedeix part de la seva energia als electrons de la mostra. La quantitat d’energia perduda es pot mesurar amb un filtre magnètic situat al final de la columna, i un gràfic que indiqui quants electrons han perdut quina quantitat d’energia ens donarà un espectre de pèrdua d’energia dels electrons, o espectre EELS. Així, en un espectre EELS l’ordenada correspon al número d’electrons, o comptes, i l’abscissa, a la pèrdua d’energia. Avui en dia l’EELS s’ha convertit en un instrument crucial a la ciència de materials, per causa de la progressiva reducció de l’escala característica implicada en el desenvolupament d’aquesta disciplina, i també gràcies a la millora instrumental que ha tingut lloc en els darrers anys tant en la microscòpia electrònica en general com en l’EELS en particular. En aquesta tesi, s’han explorat les capacitats de l’EELS com a eina de caracterització de mostres d’estat sòlid a la nanoescala, i s’han aplicat a diversos problemes de ciència de materials.
Graham, John F. "Quantitative nanoscale studies of materials by interfacial force microscopy (IFM)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0008/NQ40260.pdf.
Повний текст джерела