Download or read book Contr le de l orientation de mol cules pour la r alisation de nanosources de lumi re written by Patrick Hsia and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce travail concerne le développement d'un nouveau type de microscopie optique en champ proche (SNOM) basé sur la mise en œuvre de sondes dite actives qui utilisent le signal de génération de seconde harmonique (SHG) d'un petit nombre de molécules orientées. L'orientation de ces molécules est obtenue par l'application d'un champ électrique statique dans une jonction constituée d'une pointe métallique effilée placée à proximité d'un substrat conducteur et immergée dans une solution de molécules dipolaires non-linéaires. L'excitation laser de ces molécules localement orientées permet d'obtenir une polarisation non-lineaire à fréquence double qui constitue une nanosource de lumière intrinsèquement localisée et pouvant interagir avec le champ proche du substrat. Nous nous sommes intéressés à l'imagerie de nano-objets lithographiés par cette technique de SNOM-SHG. Nous avons pu démontrer la possibilité d'obtenir une résolution de l'ordre de 200 nm, soit une résolution meilleure d'un facteur 2 par rapport à la limite de diffraction.Nous avons ensuite étudié les moyens d'optimiser les performances de ce nouveau type de sondes SNOM-SHG. Une voie consiste à exploiter les propriétés d'antenne optique de pointes métalliques effilées, qui peuvent être le siège d'effets d'exaltation du champ électromagnétique résultant de la singularité géométrique de ces objets (extrémité effilée) ou de l'excitation de résonances plasmons. Afin de pouvoir quantifier ces effets, nous avons entrepris la caractérisation, par luminescence à 2 photons (TPL), de nanofils d'or considérés comme objets de référence pour mimer une pointe. Des fils lithographiés ainsi que des fils issus de chimie colloïdale ont été étudiés de façon à mieux comprendre à la fois l'influence de la forme et de la cristallinité des objets sur les exaltations de champ. Des études simultanées de la géométrie et des propriétés optiques d'un nanofil unique ont été menées au moyen d'un microscope optique inversé associé à une excitation laser et couplé à un microscope à force atomique (AFM) dont la pointe est préalablement réglée pour coïncider avec le spot laser. En balayant l'échantillon, nous pouvons directement confronter l'image topographique de l'objet à la cartographie de points chauds enregistrés à sa surface, le signal de TPL étant directement corrélé à la densité locale d'états électromagnétiques. Nous avons pu montrer que les fils lithographiés et les fils colloïdaux présentaient des facteurs d'exaltation locale de champ différents, la cristallinité des objets pouvant aussi être révélée que via l'analyse spectrale du signal de TPL émis. Enfin, un dernier volet important de mon travail a consisté à faire évoluer le banc expérimental précédemment développé au laboratoire de façon à pouvoir réaliser simultanément des caractérisations de type SNOM-SHG et des caractérisations topographiques. Dans ce but, nous avons travaillé à l'intégration d'une tête AFM diapason sur notre banc de microscopie non-linéaire. Au-delà des aspects électroniques liés à l'optimisation du fonctionnement de ce diapason, le couplage du faisceau laser dans le microscope a également été entièrement reconfiguré.
Download or read book Diffusion in Materials DIMAT 2011 written by Igor Bezverkhyy and published by Trans Tech Publications Ltd. This book was released on 2012-04-12 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Conference on Diffusion in Materials (DIMAT) is the benchmark conference series for diffusion in solids. DIMAT 2011 was organized by the University of Bourgogne in association with CNRS, Dijon (France). The conference showcased new results concerning theoretical tools as well as applied research approaches. Diffusion processes affect all types of materials: nanomaterials, materials for energy, metallurgy, glasses and ceramics, but each requires its own numerical tools. Volume is indexed by Thomson Reuters CPCI-S (WoS). This volume comprises most of the contributions presented at DIMAT 2011: 4 plenary lectures delivered by famous high-level scientists plus 88 contributions in the form of keynote lectures, talks and posters.
Download or read book The Mie Theory written by Wolfram Hergert and published by Springer. This book was released on 2012-06-30 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents in a concise way the Mie theory and its current applications. It begins with an overview of current theories, computational methods, experimental techniques, and applications of optics of small particles. There is also some biographic information on Gustav Mie, who published his famous paper on the colour of Gold colloids in 1908. The Mie solution for the light scattering of small spherical particles set the basis for more advanced scattering theories and today there are many methods to calculate light scattering and absorption for practically any shape and composition of particles. The optics of small particles is of interest in industrial, atmospheric, astronomic and other research. The book covers the latest developments in divers fields in scattering theory such as plasmon resonance, multiple scattering and optical force.
Download or read book The Discharge of Electricity Through Gases written by Joseph John Thomson and published by . This book was released on 1898 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pioneering work that helped us to better understand the nature of cathode rays.
Download or read book Notes On Recent Researches in Electricity and Magnetism Intended As a Sequel to Professor Clerk Maxwell s Treatise On Electricity and Magnetism written by Joseph John Thomson and published by Legare Street Press. This book was released on 2022-10-26 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Nano Bioremediation Fundamentals and Applications written by Hafiz M. N. Iqbal and published by Elsevier. This book was released on 2021-11-10 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-Bioremediation: Fundamentals and Applications explores how nano-bioremediation is used to remedy environmental pollutants. The book's chapters focus on the design, fabrication and application of advanced nanomaterials and their integration with biotechnological processes for the monitoring and treatment of pollutants in environmental matrices. It is an important reference source for materials scientists, engineers and environmental scientists who are looking to increase their understanding of bioremediation at the nanoscale. The mitigation of environmental pollution is the biggest challenge to researchers and the scientific community, hence this book provides answers to some important questions. As an advanced hybrid technology, nano-bioremediation refers to the integration of nanomaterials and bioremediation for the remediation of pollutants. The rapid pace of urbanization, massive development of industrial sectors, and modern agricultural practices all cause a controlled or uncontrolled release of environmentally-related hazardous contaminants that are seriously threatening every key sphere, including the atmosphere, hydrosphere, biosphere, lithosphere, and anthroposphere. Explores the current and potential applications of nano-bioremediation in the remediation of hazardous pollutants Outlines the major properties and classes of nanomaterials that make them efficient bioremediation agents Assesses the major challenges of effectively implementing bioremediation techniques at the nanoscale
Download or read book Chrysotype written by Leanne McPhee and published by CRC Press. This book was released on 2020-10-27 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chrysotype is about photographic printing in gold on paper. This 19th century printing process, modified for contemporary use, provides artists with an affordable way to produce permanent prints in gold. By using film or digital negatives, striking hand-coated prints can be created in monochromatic hues ranging from pink, violet, magenta and purple, to green, blue, grey and black. Chrysotype offers a how-to guide for intermediate practitioners with illustrated examples and simple explanations for each stage of the chrysotype process. The book is divided into three sections: history; preparation and how-to; and the work of contemporary artists using chrysotype. This book includes: A concise account of the invention and modification of the chrysotype process, including early discoveries about gold and colour and the significance of moisture for printing in gold How to set up your workspace for printing, including useful equipment and materials Advice on safe chemical practice A step-by-step guide to creating suitable digital and film negatives Guidance on paper selection and how to successfully coat paper An overview guide to creating a chrysotype print Step-by step directions for creating the chrysotype solutions An explanation of mixing ratios and solution volumes that control contrast An illustrated explanation of the effect of humidity on colour, including split tone colours and ways to control humidity Step-by-step directions on post-exposure hydration to lengthen tonal range and lower contrast Step-by-step tray processing directions Advanced techniques such as handling translucent papers, additional chrysotype formulas and procedures, and alternative developing agents that support longer development, colour formation and remedy problems that affect image quality Troubleshooting chrysotype printing, including advice and photographic examples Illustrated profiles of contemporary artists making chrysotype prints, including their methods and tips Chrysotype serves to inform, encourage and challenge a new generation of alternate process practitioners and a growing chrysotype community, from the newly curious to the experienced professional.
