Electrodeposition of gold nanowires in etched ion track templates ab 49 € als Taschenbuch: Structural and electrical properties and Rayleigh Instability of gold nanowires. Aus dem Bereich: Bücher, Wissenschaft, Physik,
Electrodeposition of gold nanowires in etched ion track templates ab 49 EURO Structural and electrical properties and Rayleigh Instability of gold nanowires
Many organisms exhibit a remarkable control overcrystal nucleation and growth. This enables them toconstruct composite materials with optimalproperties. They use modified forms ofminerals such as calcite, which are abundant innature, but lack the right properties in theirnatural form. In this thesis it is shown that a Self AssembledMonolayer (SAM) of thiol molecules on gold filmsacts as a template for epitaxial nucleation ofcalcite and is able to modify its shape. Such SAM''sare therefore a good model systemfor organic templates used in nature. Furthermore itis shown that SAM''s decrease the nucleationbarrier significantly due to the negative charge andthe relative ordering ofthe functional groups. This leads to critical clustersizes that are muchsmaller for crystals formed on the SAM than withinthe solution. While knowledge creation lies at the heart ofscientific research, its role typically remainsimplicit in studies of the practices and themanagement of that research. This research shows theoutstanding but undervalued importance ofsocialization processes, whereas many research groupsfocus on output instead of creating the rightsocial context.
Electrochemical synthesis of poly- and single-crystalline Au wires with diameters ranging down to 25 nm in porous polycarbonate templates is described. These templates have been prepared using heavy-ion irradiation and subsequent transformation of the ion tracks into nanopores by chemical etching. Crystallographic and morphological properties of these nanowires have been investigated by X-ray diffraction, transmission and scanning electron microscopy. The effect of deposition conditions including temperature, electrolyte, voltage signal and diameter on the texture of gold nanowires is investigated and described in detail in this work. In addition, the structural stability of wires is discussed in detail. The wires became morphologically fragile due to Rayleigh instability when annealed at high temperatures. During this process they fragmented into nanospheres at temperatures far below the bulk melting point. Thus a wire with diameter 25 nm decayed already at 300 oC. The electrical resistance of single gold nanowires, embedded in the template, has also been investigated.
Block copolymers are fascinating materials that have attracted a lot of attention in recent years, as a consequence of their ability to serve as ideal building blocks to fabricate nanostructures. They are macromolecules consisting of chemically different parts (blocks) that tend to self-assembly into well-ordered nanoscaled structures both in bulk and in a selective solvent for one of the block. In this thesis, amphiphilic block copolymers were successfully applied as templates for the controlled formation and defined positioning of metal and metal oxide nanoparticles arranged in periodic patterns on flat surfaces and in polymer nanofibre structures. Furthermore, a method was developed to arrange nanoparticles in desired nano-structured micropatterns on flat substrates using the combinations of "top_down" and "bottom-up" approaches: a self-assembled monolayer of hexagonally ordered block copolymer micelles loaded with gold precursor salt was used as a resist for lithography. Two diffrent energy sources were applied to selectively modify and pin the micelles to the substrate: UV light and s Focus Ion Beam.
This thesis explores the fabrication of gyroid-forming block copolymer templates and the optical properties of the resulting gyroid optical metamaterials, significantly contributing to our understanding of both. It demonstrates solvent vapour annealing to improve the long-range order of the templates, and investigates the unique crystallisation behaviour of their semicrystalline block. Furthermore, it shows that gyroid optical metamaterials that exhibit only short-range order are optically equivalent to nanoporous gold, and that the anomalous linear dichroism of gyroid optical metamaterials with long-range order is the result of the surface termination of the bulk gyroid morphology.Optical metamaterials are artificially engineered materials that, by virtue of their structure rather than their chemistry, may exhibit various optical properties not otherwise encountered in nature (e.g. a negative refractive index). However, these structures must be significantly smaller than the wavelength of visible light and are therefore challenging to fabricate using traditional "top down" techniques. Instead, a "bottom up" approach can be used, whereby optical metamaterials are fabricated via templates created by the self-assembly of block-copolymers. One such morphology is the gyroid, a chiral, continuous and triply periodic cubic network found in a range of natural and synthetic self-assembled systems.
More than merely a writing text, The Imaginative Argument offers writers instruction on how to use their imaginations to improve their prose. Cioffi shows writers how they can enliven argument--the organizing rubric of all persuasive writing--by drawing on emotion, soul, and creativity, the wellsprings of imagination. While Cioffi suggests that argument should become a natural habit of mind for writers, he goes still further, inspiring writers to adopt as their gold standard the imaginative argument: the surprising yet strikingly apt insight that organizes disparate noises into music, that makes out of chaos, chaos theory. Rather than offering a model of writing based on established formulas or templates, Cioffi urges writers to envision argument as an active parsing of experience that imaginatively reinvents the world. Cioffi's manifesto asserts that successful argument also requires writers to explore their own deep-seated feelings, to exploit the fuzzy but often profoundly insightful logic of the imagination. But expression is not all that matters: Cioffi's work anchors itself in the actual. Drawing on Louis Kahn's notion that a good architect never has all the answers to a building's problems before its physical construction, Cioffi maintains that in argument, too, answers must be forged along the way, as the writer inventively deals with emergent problems and unforeseen complexities. Indeed, discovery, imagination, and invention suffuse all stages of the process. The Imaginative Argument offers all the intellectual kindling that writers need to ignite this creativity, from insights on developing ideas to avoiding bland assertions or logical leaps. It cites exemplary nonfiction prose stylists, including William James, Ruth Benedict, and Erving Goffman, as well as literary sources to demonstrate the dynamic of persuasive writing. Provocative and lively, it will prove not only essential reading but also inspiration for all those interested in arguing more imaginatively more successfully.
'The book's use of real-world case study vignettes really does go to the heart of the subject matter. This stuff is real, it has real applicability to real problems, and, as with most things in life, it shows how it all comes down to real money in the final analysis. This book shows you what your peers are doing to drive costs out of integration projects and to build new applications without re-inventing the entire wheel-just a few new spokes and off you go. This is a good book. Read it.' - Peter Rhys Jenkins , Complex Systems Architect, Candle Corporation 'When you get two long-term, acknowledged experts on integration and interoperability together to lay out the current state of the IT universe you expect an immediate return on investment-and this book delivers. It's common knowledge that 90% of total software lifecycle cost is in maintenance and integration, and that needs to drive IT decision-making. With comprehensive coverage of the integration technology landscape, and clear case studies presented at every turn, this book belongs on every IT manager's, every system architect's, and every software developer's bookshelf.' - Richard Mark Soley , chairman and CEO, Object Management Group 'Today's myriad of integration technologies and alternatives can be daunting. This book presents a framework and process for the evaluation, design, and selection of the appropriate integration technologies to meet your strategic business needs. You will find the templates a particularly useful mechanism to jump-start documentation and drive your decision-making process.' - Ron Zahavi , CIO, Global Business Transformation, Unisys Global Transformation Team; author of Enterprise Application Integration with CORBA 'It is refreshing to read a book that presents a good business approach to the integration challenge facing most business leaders today, while at the same time educating them about the major components of the required technologies and management practices changes required. The narrative, examples, and templates establish a common reference point between the business and the technology organizations. A must-read for senior business leaders challenged with the complexities of business integration, as well as Senior IT Leaders challenged with shrinking budgets and lower tolerances for failures.' - Chuck Papageorgiou , managing partner, Ideasphere 'Integration has, and will continue to be, one of the success indicators of any enterprise project. Failing to understand the nuances of integration is a critical mistake managers cannot afford to make.' - Marcia Robinson , author of Services Blueprint: Roadmap for Execution 'A much-needed book; it ties together the business and technology aspects of information system implementation, emphasizing best practices for really getting things done. I believe that both the technical and business communities will benefit from the in-depth material provided in this book.' - Dr. Barry Horowitz , professor of systems and information engineering, University of Virginia (former CEO, Mitre Corporation) Integration of applications, information, and business process has become today's #1 IT investment priority. Most enterprise integration books simply explain the technology. This one shows exactly how to apply it. It's a step-by-step roadmap for your entire project-from the earliest exploratory stages through analysis, design, architecture, and implementation. Renowned enterprise integration experts Beth Gold-Bernstein and William Ruh present best practices and case studies that bring their methodology to life. They address every stage from the decision-maker's and implementer's point of view-showing how to align business requirements to
This thesis explores the fabrication of gyroid-forming block copolymer templates and the optical properties of the resulting gyroid optical metamaterials, significantly contributing to our understanding of both. It demonstrates solvent vapour annealing to improve the long-range order of the templates, and investigates the unique crystallisation behaviour of their semicrystalline block. Furthermore, it shows that gyroid optical metamaterials that exhibit only short-range order are optically equivalent to nanoporous gold, and that the anomalous linear dichroism of gyroid optical metamaterials with long-range order is the result of the surface termination of the bulk gyroid morphology. Optical metamaterials are artificially engineered materials that, by virtue of their structure rather than their chemistry, may exhibit various optical properties not otherwise encountered in nature (e.g. a negative refractive index). However, these structures must be significantly smaller than the wavelength of visible light and are therefore challenging to fabricate using traditional &#8220;top down&#8221; techniques. Instead, a &#8220;bottom up&#8221; approach can be used, whereby optical metamaterials are fabricated via templates created by the self-assembly of block-copolymers. One such morphology is the gyroid, a chiral, continuous and triply periodic cubic network found in a range of natural and synthetic self-assembled systems.