Surface crystallography plays the same fundamental role in surface science which bulk crystallography has played so successfully in solid-state physics and chemistry. The atomic-scale structure is one of the most important aspects in the understanding of the behavior of surfaces in such widely diverse fields as heterogeneous catalysis, microelectronics, adhesion, lubrication, cor rosion, coatings, and solid-solid and solid-liquid interfaces. Low-Energy Electron Diffraction or LEED has become the prime tech nique used to determine atomic locations at surfaces. On one hand, LEED has yielded the most numerous and complete structural results to date (almost 200 structures), while on the other, LEED has been regarded as the "technique to beat" by a variety of other surface crystallographic methods, such as photoemission, SEXAFS, ion scattering and atomic diffraction. Although these other approaches have had impressive successes, LEED has remained the most productive technique and has shown the most versatility of application: from adsorbed rare gases, to reconstructed surfaces of sem iconductors and metals, to molecules adsorbed on metals. However, these statements should not be viewed as excessively dogmatic since all surface sensitive techniques retain untapped potentials that will undoubtedly be explored and exploited. Moreover, surface science remains a multi-technique endeavor. In particular, LEED never has been and never will be self sufficient. LEED has evolved considerably and, in fact, has reached a watershed.
The development of a commercially successful process for the catalytic synthesis of ammonia was a scientific as well as a technical triumph. Its implications were con siderable. It demonstrated the power of a combination of innovative technology and engineering together with basic chemical science, and it introduced ideas and techniques into catalytic science and process engineering which are still with us today. In a real sense, this process changed the face of industrial chemistry and process technology. Of course, the key step in the direct synthesis of ammonia was the development of an efficient catalyst, and the historical account given by Dr. S. A. Topham in the first chapter of this volume shows how this was success fully accomplished, and how this was combined with the successful solution of other daunting technical problems to make the overall process possible. The microstructure of a catalyst is an important feature which determines its behaviour, and the electron microscope is one of the most important instrumental methods by means of which structural and microstruc tural information can be obtained. Nevertheless, the elec tron-optical processes of image formation are complex, but need to be properly understood if image interpreta tion is to be done reliably. In the second chapter of this volume, Dr. J. V. Sanders addresses the entire field of the application of electron microscopic methods to the examination of catalysts.
This book aims to popularize physics by emphasizing conceptual ideas of physics and their interconnections, while avoiding mathematics entirely. The approach is to explore intriguing topics of daily relevance by asking and discussing questions: thereby the reader can participate in developing answers, which enables a deeper understanding than is achievable with memorization.The topic of this book — waves — is chosen because we experience waves in many forms every minute of our lives, from sound waves and light waves to quantum waves and brain waves.The target readership of this book is very broad: all those with a curious mind about nature and with a desire to understand how nature works, especially laymen, youngsters, secondary-school children and their teachers.
Surface crystallography is a discipline which has come of age. There exist in the literature several hundred complete determinations of atomic configurations at surfaces: yet the number is not so great that cataloguing these structures is too daunting a task. We felt that now was the right moment to begin a compilation that could be updated at frequent intervals to give a comprehensive picture of the known surface world. The following pages are the product of our labours. Our target community is the large number of surface chemists, materials scientists, physicists and others whose work involves surfaces. As the compilation expands with time our hope is that it will become one of the standard reference works for structures: in the manner that Wyckoff and other X-ray tables are for bulk crystals. We have devoted considerable thought to the format. The system we have chosen will no doubt have its critics, and in subsequent editions may well be improved, but it has been arrived at after extensive consultation. A problem that we faced in putting structures into standard format was the diversity of conventions used in the literature. It is to be hoped that our system will have sufficient virtue to serve as a standard format for future reporting of structures. That would make it much easier for surface crystallographers to use the work of others.
Noise is ubiquitous in nature and in man-made systems. Noise in oscillators perturbs high-technology devices such as time standards or digital communication systems. The understanding of its algebraic structure is thus of vital importance. The book addresses both the measurement methods and the understanding of quantum, 1/f and phase noise in systems such as electronic amplifiers, oscillators and receivers, trapped ions, cosmic ray showers and in commercial applications. A strong link between 1/f noise and number theory is emphasized. The twenty papers in the book are comprehensive versions of talks presented at a school in Chapelle des Bois (Jura, France) held from April 6 to 10, 1999, by engineers, physisicts and mathematicians.
This book aims to popularize physics by emphasizing conceptual ideas of physics and their interconnections, while avoiding mathematics entirely. The approach is to explore intriguing topics by asking and discussing questions, thereby the reader can participate in developing answers, which enables a deeper understanding than is achievable with memorization.The topic of this volume, 'Colors, light and Optical Illusions', is chosen because we face colors and light every waking minute of our lives, and we experience optical illusions much more often than we realize.This book will attract all those with a curious mind about nature and with a desire to understand how nature works, especially the younger generation of secondary-school children and their teachers.
1 The Investigation of Hole States in Nuclei by Means of Knockout and Other Reactions.- 1. Introduction.- 2. Formalism for Knockout and Pickup Reactions.- 2.1. The Matrix Element and Overlap Integral.- 2.2 The Single-Nucleon Case.- 2.3. The Two-Nucleon Case.- 2.4. The Multi-Nucleon Case.- 2.5. Distortion and Finite-Range Effects.- 3. Single-Nucleon Knockout and Related Reactions.- 3.1. Comparison of Knockout and Pickup Reactions.- 3.2. Special Features of Knockout Reactions.- 3.3. Spectroscopic Studies.- 3.4. Proton States.- 3.5. Neutron States.- 4. Cluster Knockout and Related Reactions.- 4.1.
The hope and hype about African digital entrepreneurship, contrasted with the reality on the ground in local ecosystems. In recent years, Africa has seen a digital entrepreneurship boom, with hundreds of millions of dollars poured into tech cities, entrepreneurship trainings, coworking spaces, innovation prizes, and investment funds. Politicians and technologists have offered Silicon Valley-influenced narratives of boundless opportunity and exponential growth, in which internet-enabled entrepreneurship allows Africa to "leapfrog" developmental stages to take a leading role in the digital revolution. This book contrasts these aspirations with empirical research about what is actually happening on the ground. The authors find that although the digital revolution has empowered local entrepreneurs, it does not untether local economies from the continent's structural legacies.
Volume 1: From Brownian Motion to Renormalization and Lattice Gauge Theory. Volume 2: Strong Coupling, Monte Carlo Methods, Conformal Field Theory, and Random Systems. This two-volume work provides a comprehensive and timely survey of the application of the methods of quantum field theory to statistical physics, a very active and fruitful area of modern research. The first volume provides a pedagogical introduction to the subject, discussing Brownian motion, its anticommutative counterpart in the guise of Onsager's solution to the two-dimensional Ising model, the mean field or Landau approximation, scaling ideas exemplified by the Kosterlitz-Thouless theory for the XY transition, the continuous renormalization group applied to the standard phi-to the fourth theory (the simplest typical case) and lattice gauge theory as a pathway to the understanding of quark confinement in quantum chromodynamics. The second volume covers more diverse topics, including strong coupling expansions and their analysis, Monte Carlo simulations, two-dimensional conformal field theory, and simple disordered systems. The book concludes with a chapter on random geometry and the Polyakov model of random surfaces which illustrates the relations between string theory and statistical physics. The two volumes that make up this work will be useful to theoretical physicists and applied mathematicians who are interested in the exciting developments which have resulted from the synthesis of field theory and statistical physics.
Surfaces and interfaces play an increasingly important role in today's solid state devices. In this book the reader is introduced, in a didactic manner, to the essential theoretical aspects of the atomic and electronic structure of surfaces and interfaces. The book does not pretend to give a complete overview of contemporary problems and methods. Instead, the authors strive to provide simple but qualitatively useful arguments that apply to a wide variety of cases. The emphasis of the book is on semiconductor surfaces and interfaces but it also includes a thorough treatment of transition metals, a general discussion of phonon dispersion curves, and examples of large computational calculations. The exercises accompanying every chapter will be of great benefit to the student.
The book contains a lot of examples, a lot of non-standard material which is not included in many other books. At the same time the authors manage to avoid numerous cumbersome calculations … It is a great achievement that the authors found a balance.'zbMATHThis book presents the study of symmetry groups in Physics from a practical perspective, i.e. emphasising the explicit methods and algorithms useful for the practitioner and profusely illustrating by examples.The first half reviews the algebraic, geometrical and topological notions underlying the theory of Lie groups, with a review of the representation theory of finite groups. The topic of Lie algebras is revisited from the perspective of realizations, useful for explicit computations within these groups. The second half is devoted to applications in physics, divided into three main parts — the first deals with space-time symmetries, the Wigner method for representations and applications to relativistic wave equations. The study of kinematical algebras and groups illustrates the properties and capabilities of the notions of contractions, central extensions and projective representations. Gauge symmetries and symmetries in Particle Physics are studied in the context of the Standard Model, finishing with a discussion on Grand-Unified Theories.
Aktuelles Handbuch über Photoemission und verwandte Methoden zur Untersuchung und Charakterisierung von kondensierter Materie. Dieses Werk bietet sowohl Experimentalphysikern als auch Theoretikern alle Informationen von den physikalischen Grundlagen über Durchführung und Interpretation von Messungen aus einer Hand. Der Inhalt umfasst die räumlichen und elektronischen Eigenschaften von Oberflächen und Grenzflächen, theoretische Methoden zur Berechnung von Spektren, experimentelle Techniken zur Datenaufnahme und physikalische Modelle zur Interpretation.
Surface crystallography plays the same fundamental role in surface science which bulk crystallography has played so successfully in solid-state physics and chemistry. The atomic-scale structure is one of the most important aspects in the understanding of the behavior of surfaces in such widely diverse fields as heterogeneous catalysis, microelectronics, adhesion, lubrication, cor rosion, coatings, and solid-solid and solid-liquid interfaces. Low-Energy Electron Diffraction or LEED has become the prime tech nique used to determine atomic locations at surfaces. On one hand, LEED has yielded the most numerous and complete structural results to date (almost 200 structures), while on the other, LEED has been regarded as the "technique to beat" by a variety of other surface crystallographic methods, such as photoemission, SEXAFS, ion scattering and atomic diffraction. Although these other approaches have had impressive successes, LEED has remained the most productive technique and has shown the most versatility of application: from adsorbed rare gases, to reconstructed surfaces of sem iconductors and metals, to molecules adsorbed on metals. However, these statements should not be viewed as excessively dogmatic since all surface sensitive techniques retain untapped potentials that will undoubtedly be explored and exploited. Moreover, surface science remains a multi-technique endeavor. In particular, LEED never has been and never will be self sufficient. LEED has evolved considerably and, in fact, has reached a watershed.
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