Download or read book Radiation Induced Topological Disorder in Irradiated Network Structures written by and published by . This book was released on 2002 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes results of a research program investigating the fundamental principles underlying the phenomenon of topological disordering in a radiation environment. This phenomenon is known popularly as amorphization, but is more formally described as a process of radiation-induced structural arrangement that leads in crystals to loss of long-range translational and orientational correlations and in glasses to analogous alteration of connectivity topologies. The program focus has been on a set compound ceramic solids with directed bonding exhibiting structures that can be described as networks. Such solids include SiO2, Si3N4, SiC, which are of interest to applications in fusion energy production, nuclear waste storage, and device manufacture involving ion implantation or use in radiation fields. The principal investigative tools comprise a combination of experimental diffraction-based techniques, topological modeling, and molecular-dynamics simulations that have proven a rich source of information in the preceding support period. The results from the present support period fall into three task areas. The first comprises enumeration of the rigidity constraints applying to (1) more complex ceramic structures (such as rutile, corundum, spinel and olivine structures) that exhibit multiply polytopic coordination units or multiple modes of connecting such units, (2) elemental solids (such as graphite, silicon and diamond) for which a correct choice of polytope is necessary to achieve correct representation of the constraints, and (3) compounds (such as spinel and silicon carbide) that exhibit chemical disorder on one or several sublattices. With correct identification of the topological constraints, a unique correlation is shown to exist between constraint and amorphizability which demonstrates that amorphization occurs at a critical constraint loss. The second task involves the application of molecular dynamics (MD) methods to topologically-generated models of amorphized network silicas. These methods are shown to generate fully connected topologically-disordered networks, equilibrated to achieve accurately-specified atomic coordinates that can be compared to correlation data derived from diffraction experiments. The MD equilibrations demonstrate the insensitivity of diffraction methods to substantial differences in intermediate-range topology, with the exception of the first diffraction peak which is shown to be uniquely sensitive to topological differences. The third task concerns application of MD simulations to amorphization of silicon carbide, which exhibits anomalous amorphizability. Amorphization of this compound is shown to derive from its facility for tolerating chemical disorder, and a critical homonuclear bond density threshold is established as a criterion for its amorphization.

Download or read book Engineering of Crystalline Materials Properties written by Juan J. Novoa and published by Springer Science & Business Media. This book was released on 2007-12-14 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects the state of the art in molecular materials. It collects the lecture notes of a series of lectures given by some of the best specialists in the field at the 2007 Erice International School of Crystallography, and also a NATO-ASI course. The school first established "where we are" in terms of modeling, design, synthesis and applications of crystalline solids with predefined properties and then defined current and possible futuristic lines of development.

Download or read book Defects in SiO2 and Related Dielectrics Science and Technology written by Gianfranco Pacchioni and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 619 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon dioxide plays a central role in most contemporary electronic and photonic technologies, from fiber optics for communications and medical applications to metal-oxide-semiconductor devices. Many of these applications directly involve point defects, which can either be introduced during the manufacturing process or by exposure to ionizing radiation. They can also be deliberately created to exploit new technologies. This book provides a general description of the influence that point defects have on the global properties of the bulk material and their spectroscopic characterization through ESR and optical spectroscopy.

Download or read book Semiconducting Chalcogenide Glass I written by Robert Fairman and published by Academic Press. This book was released on 2004-05-10 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chalcogenide glass is made up of many elements from the Chalcogenide group. The glass is transparent to infrared light and is useful as a semiconductor in many electronic devices. For example, chalcogenide glass fibers are a component of devices used to perform laser surgery. This book is a comprehensive survey of the current state of science and technology in the field of chalcogenide semiconductor glasses. While the majority of the book deals with properties of chalcogenide glass, chapters also deal with industrial applications, synthesis and purification of chalcogenide glass, and glass structural modification. The first individual or collective monograph written by Eastern European scientists known to Western readers regarding structural and chemical changes in chalcogenide vitreous semiconductors(CVS)Chapters written by B.G. Kolomiets who discovered the properties of chalcogenide glass in 1955Provides evidence and discussion for problems discussed by authors from opposing positions.

Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1995-04 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory for Computer Science Progress Report written by Massachusetts Institute of Technology. Laboratory for Computer Science and published by . This book was released on 1997 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1989 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Analytical Electron Microscopy written by John Hren and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 609 pages. Available in PDF, EPUB and Kindle. Book excerpt: The birth of analytical electron microscopy (AEM) is somewhat obscure. Was it the recognition of the power and the development of STEM that signaled its birth? Was AEM born with the attachment of a crystal spectrometer to an otherwise conventional TEM? Or was it born earlier with the first analysis of electron loss spectra? It's not likely that any of these developments alone would have been sufficient and there have been many others (microdiffraction, EDS, microbeam fabrication, etc.) that could equally lay claim to being critical to the establishment of true AEM. It is probably more accurate to simply ascribe the present rapid development to the obvious: a combination of ideas whose time has come. Perhaps it is difficult to trace the birth of AEM simply because it remains a point of contention to even define its true scope. For example, the topics in this book, even though very broad, are still far from a complete description of what many call AEM. When electron beams interact with a solid it is well-known that a bewildering number of possible interactions follow. Analytical electron microscopy attempts to take full qualitative and quantitative advantage of as many of these interactions as possible while still preserving the capability of high resolution imaging. Although we restrict ourselves here to electron transparent films, much of what is described applies to thick specimens as well. Not surprisingly, signals from all possible interactions cannot yet (and probably never will) be attained simultaneously under optimum conditions.

Download or read book Materials Modification by Electronic Excitation written by Noriaki Itoh and published by Cambridge University Press. This book was released on 2001 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electronic excitation is a means to change materials properties. This book analyses the important features of the changes induced by electronic excitation, identifies what is critical, and provides a basis from which materials modification can be developed successfully. Electronic excitation by lasers or electron beams can change the properties of materials. In the last few years, there has been a mix of basic science, of new laser and electron beam tools, and of new needs from microelectronics, photonics and nanotechnology. This book extends and synthesises the science, addressing ideas like energy localisation and charge localisation, with detailed comparisons of experiment and theory. It also identifies the ways this understanding links to technological needs, like selective removal of material, controlled changes, altering the balance between process steps, and possibilities of quantum control. This book will be of particular interest to research workers in physics, chemistry, electronic engineering and materials science.

Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 1602 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1992 with total page 914 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adult CNS Radiation Oncology written by Eric L. Chang and published by Springer. This book was released on 2018-07-27 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book elucidates the radiation therapy protocols and procedures for the management of adult patients presenting with primary benign and malignant central nervous system tumors. With the development of new treatment strategies and rapid advancement of radiation technology, it is crucial for radiation oncologists to maintain and refine their knowledge and skills. Dedicated exclusively to adult CNS radiation oncology, this textbook explores CNS tumors ranging from the common to the esoteric as well as secondary cancers of metastatic origin. The first half of the book is organized anatomically: tumors of the brain, spinal cord, leptomeninges, optic pathway, ocular choroid, and skull base. The second half covers primary CNS lymphoma, rare CNS tumors, metastatic brain disease, vascular conditions of the CNS, radiation-associated complications, and radiation modalities. Each chapter provides guidance on treatment field design, target delineation, and normal critical structure tolerance constraints in the context of the disease being treated. Learning objectives, case studies, and Maintenance of Certification Self-Assessment Continuing Medical Education-style questions and answers are incorporated throughout the book. This is an ideal guide for radiation oncologists, residents, and fellows, but medical students may also find value in the text.

Download or read book Metals Abstracts Index written by and published by . This book was released on 1995 with total page 1596 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book INIS Atomindex written by and published by . This book was released on 1995 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Index Medicus written by and published by . This book was released on 2004 with total page 2454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.