Bücher der Reihe Nato Science Series E:

Heterogeneous catalysis provides the backbone of the world's chemical and oil industries. The innate complexity of practical catalytic systems suggests that useful progress should be achievable by investigating key aspects of catalysis by experimental studies on idealised model systems. Thin films and supported clusters are two promising types of model system that can be used for this purpose, since they mimic important aspects of the properties of practical dispersed catalysts. Similarly, appropriate theoretical studies of chemisorption and surface reaction clusters or extended slab systems can provide valuable information on the factors that underlie bonding and catalytic activity. This volume describes such experimental and theoretical approaches to the surface chemistry and catalytic behaviour of metals, metal oxides and metal/metal oxide systems. An introduction to the principles and main themes of heterogeneous catalysis is followed by detailed accounts of the application of modern experimental and theoretical techniques to fundamental problems. The application of advanced experimental methods is complemented by a full description of theoretical procedures, including Hartree-Fock, density functional and similar techniques. The relative merits of the various approaches are considered and directions for future progress are indicated.

Among the many intense light sources, excimer lasers have a unique set of properties that place them at the forefront of tooling for material processing. Their extreme versatility means that they can be used in many areas of materials science and medicine. But three conditions need to be fulfilled in order that their versatility be truly appreciated and exploited: the characteristics and limitations of the sources must be known; the basic excimer laser processes should become reasonably widely known; and problems in search of a solution should be clearly identified. Excimer Lasers covers all three of these points in an instructive and logical way. Probably for the first time, both instrumental and fundamental aspects of excimer laser interaction with matter are presented side-by-side, with examples drawn from the widest range of materials. The articles gathered here are tutorial in their nature, thus making them suitable for a wide readership, from recent graduates and postgraduate students to those established scientists entering the field, all of whom could not find a better, nor more authoritative work with which to start their reading.

Sensors and Sensory Systems for an Electronic Nose reviews the current state of progress in the development of an electronic instrument capable of olfaction. The instrument -- the so-called electronic nose -- has enormous potential for application in such areas as product flavor control and environmental monitoring. The book discusses the essential elements of an electronic nose, such as chemical sensors, signal processing, and pattern recoginiton techniques. It is also one of the first contributions to the new and exciting field of machine olfaction.

Within the last 10 years the world has come to a point where the easily explorable oil deposits have now been found, and it is anticipated that such deposits will be depleted by the beginning of the Twenty-first Century. However, the increasing demand of man- kind for energy has caused technologists to look into ways of find- ing new sources or to reevaluat:e unconventional sources which, in the past, have not been economical. In this respect, heavy crude and tar sand oils are becoming important in fulfilling the world's energy requirements. What are heavy crude and tar sand oils? There is still some confusion as to their definitions, inasmuch as they vary among organizations and countries. In an effort to set agreed meanings, UNITAR, in a meeting in February 1982 in Venezuela, proposed the following definitions (see also Table 1): 1. Heavy crude oil and tar sand oil are petroleum or petroleum- like liquids or semi-solids naturally occurring in porous media. The porous media are sands, sandstone, and carbonate rocks. 2. These oils will be characterized by viscosity and density. Viscosity will be used to define heavy crude oil and tar sand oil, and density (oAPI) will be used when viscosity measurements are not available. 3. Heavy crude oil has a gas-free viscosity of 100-10000 mPa.s (cp) 3 o at reservoir temperatures, or a density of 943 kg/m (20 API) 3 o o to 1000 kg/m (10 API) at 15.6 C and at atmospheric oressure.

After an introduction by J.G. Bednorz, describing the discovery of high Tc superconductivity and its consequences, the book goes on to describe modern research, dealing with general problems, new materials and structures, phase separation, electronic homogeneities and related problems, and applications. Specific systems dealt with include the La-cuprates. the Bi-cuprates and the Y-cuprates and related compounds.

The workshop on "e;Optical Properties of Low Dimensional Silicon sL Structures"e; was held in Meylan, France on March, I yd, 1993. The workshop took place inside the facilities of France Telecom- CNET. Around 45 leading scientists working on this rapidly moving field were in attendance. Principal support was provided by the Advanced Research Workshop Program of the North Atlantic Treaty Organisation (NATO). French Delegation a l'Armement and CNET gave also a small financial grant, the organisational part being undertaken by the SEE and CNET. There is currently intense research activity worldwide devoted to the optical properties of low dimensional silicon structures. This follow the recent discovery of efficient visible photoluminescence (PL) from highly porous silicon. This workshop was intended to bring together all the leading European scientists and laboratories in order to reveal the state of the art and to open new research fields on this subject. A large number of invited talks took place (12) together with regular contribution (20). The speakers were asked to leave nearly 1/3 of the time to the discussion with the audience, and that promoted both formal and informal discussions between the participants.

The NATO Advanced Research Workshop on "e;Nanomagnetic Devices"e; was held in Miraflores de la Sierra, Madrid, Spain, from 14 to 19 September 1992. This book contains 21 invited articles related to suggestive and relevant aspects of Magnetism. The NATO Advanced Research Workshop was Co-directed by R.C. O'Handley, B. Heinrich and A. Hernando. The organisers as well as the participants are gratefully acknowledged to the NATO Science Committee. I also wish to thank the publishers for their advice and help in organizing the book. xi DESIDERATA OF STORAGE DEVICES C.E. YEACK-SCRANTON IBM Corporation, E02/005 5600 Cottle Road San Jose, CA 95139 USA ABSTRACT. Typical requirements on cost, capacity, and performance of today's magnetic storage devices and industry trends in these attributes are given. Scaling components, devices, and materials is shown to be a key factor in further improvement, Challenges to continued scaling are reviewed, particularly as they relate to magnetic nano-structures, materials, and characterization techniques.

Proceedings of the NATO Advanced Study Institute, Cesme, Izmir, Turkey, 27 June-8 July, 1988

John Keats, writing to Fanny Brawne [1], said "I long to believe in immortality ¿¿¿¿¿ I wish to believe in immortality - I wish to live with you forever". So much of this talk will be concerned with the ductile behaviour of crystals, plasticity in its narrower sense. We shall consider a crystal which is deforming by slip, and shall expose a surface in this crystal. We first think of the sur­ face as a simple mathematical cut along a low-index plane. Then we allow for the relaxation of the newly-exposed atoms, and for surface irregularities, and we consider the effect of lattice va­ cancies which can enter at the surface. We consider the effect of dissolving off the surface layers, either intermittently or contin­ uously. Then the effects of adsorption or oxidation by normal con­ stituents of the atmosphere must be considered, the effects of sur­ face alloying, and finally those of special surface-active agents. But "All/Life death does end and each day dies with sleep" [2], and plasticity in its broader sense includes the fracture ~'1hich term­ inates flow. Here there is a bewildering array of effects. The medium in which the crystal flows may enhance its ductility enor­ mously, or it may cause it to break almost without plastic deform­ ation, or under a load which it has already supported.

Model based control has emerged as an important way to improve plant efficiency in the process industries, while meeting processing and operating policy constraints. The reader of Methods of Model Based Process Control will find state of the art reports on model based control technology presented by the world's leading scientists and experts from industry. All the important issues that a model based control system has to address are covered in depth, ranging from dynamic simulation and control-relevant identification to information integration. Specific emerging topics are also covered, such as robust control and nonlinear model predictive control. In addition to critical reviews of recent advances, the reader will find new ideas, industrial applications and views of future needs and challenges. Audience: A reference for graduate-level courses and a comprehensive guide for researchers and industrial control engineers in their exploration of the latest trends in the area.

The main motivation for the organization of the Advanced Research Workshop in Belgirate was the promotion of discussions on the most recent issues and the future perspectives in the field of Solid State lonics. The location was chosen on purpose since Belgirate was the place were twenty years ago, also then under the sponsorship of NATO, the very first international meeting on this important and interdisciplinary field took place. That meeting was named "e;Fast Ion Transport in Solids"e; and gathered virtually everybody at that time having been active in any aspect of motion of ions in solids. The original Belgirate Meeting made for the first time visible the technological potential related to the phenomenon of the fast ionic transport in solids and, accordingly, the field was given the name "e;Solid State lonics"e;. This field is now expanded to cover a wide range of technologies which includes chemical sensors for environmental and process control, electrochromic windows, mirrors and displays, fuel cells, high performance rechargeable batteries for stationary applications and electrotraction, chemotronics, semiconductor ionics, water electrolysis cells for hydrogen economy and other applications. The main idea for holding an anniversary meeting was that of discussing the most recent issues and the future perspectives of Solid State lonics just twenty years after it has started at the same location on the lake Maggiore in North Italy.

In the near future the world will need to convert to a suitable, clean energy supply: one that will meet the demands of an increasing population while giving few environmental problems. One such possible supply is hydrogen. Hydrogen Energy System describes the present status of hydrogen as an energy supply, as well as its prospect in the years to come. It covers the transition to hydrogen-based, sustainable energy systems, the technology of hydrogen production, its storage and transport, and current and future hydrogen utilisation. Economic analyses of the hydrogen energy system, together with case studies, are also presented.

A detailed study of the science, engineering and applications of terahertz technology, based on room-temperature solid-state devices, which are seen as the key technology for wider applications in this frequency range. The relative merits of electronic and optical devices are discussed and new device principles identified. Issues of terahertz circuit design, implementation and measurement are complemented by chapters on current and future applications in communications, sensing and remote surveillance. Audience: The unique coverage of all aspects of terahertz technology will appeal to both new and established workers in the field, as well as providing a survey for the interested reader.

Photonic band gap crystals offer unique ways to tailor light and the propagation of electromagnetic waves. In analogy to electrons in a crystal, EM waves propagating in a structure with a periodically-modulated dielectric constant are organized into photonic bands separated by gaps in which propagating states are forbidden. Proposed applications of such photonic band gap crystals, operating at frequencies from microwave to optical, include zero- threshold lasers, low-loss resonators and cavities, and efficient microwave antennas. Spontaneous emission is suppressed for photons in the photonic band gap, offering novel approaches to manipulating the EM field and creating high-efficiency light-emitting structures. Photonic Band Gap Materials identifies three most promising areas of research. The first is materials fabrication, involving the creation of high quality, low loss, periodic dielectric structures. The smallest photonic crystals yet fabricated have been made by machining Si wafers along (110), and some have lattice constants as small as 500 microns. The second area is in applications. Possible applications presented are microwave mirrors, directional antennas, resonators (especially in the 2 GHz region), filters, waveguides, Y splitters, and resonant microcavities. The third area covers fundamentally new physical phenomena in condensed matter physics and quantum optics. An excellent review of recent development, covering theoretical, experimental and applied aspects. Interesting and stimulating reading for active researchers, as well as a useful reference for non-specialists.

Techniques for the preparation of condensed matter systems have advanced considerably in the last decade, principally due to the developments in microfabrication technologies. The widespread availability of millikelvin temperature facilities also led to the discovery of a large number of new quantum phenomena. Simultaneously, the quantum theory of small condensed matter systems has matured, allowing quantitative predictions. The effects discussed in Quantum Dynamics of Submicron Structures include typical quantum interference phenomena, such as the Aharonov-Bohm-like oscillations of the magnetoresistance of thin metallic cylinders and rings, transport through chaotic billiards, and such quantization effects as the integer and fractional quantum Hall effect and the quantization of the conductance of point contacts in integer multiples of the `conductance quantum'. Transport properties and tunnelling processes in various types of normal metal and superconductor tunnelling systems are treated. The statistical properties of the quantum states of electrons in spatially inhomogeneous systems, such as a random, inhomogeneous magnetic field, are investigated. Interacting systems, like the Luttinger liquid or electrons in a quantum dot, are also considered. Reviews are given of quantum blockade mechanisms for electrons that tunnel through small junctions, like the Coulomb blockade and spin blockade, the influence of dissipative coupling of charge carriers to an environment, and Andreev scattering. Coulomb interactions and quantization effects in transport through quantum dots and in double-well potentials, as well as quantum effects in the motion of vortices, as in the Aharonov-Casher effect, are discussed. The status of the theory of the metal-insulator and superconductor-insulator phase transitions in ordered and disordered granular systems are reviewed as examples in which such quantum effects are of great importance.

Intersubband transitions in quantum wells have attracted tremendous attention in recent years, mainly due to the promise of applications in the mid and far-infrared regions (2--20 mum). Many of the papers presented in Quantum Well Intersubband Transition Physics and Devices are on the basic linear intersubband transition processes, detector physics and detector application, reflecting the current state of understanding and detector applications, where highly uniform, large focal plane arrays have been demonstrated. Other areas are still in their early stages, including infrared modulation, harmonic generation and emission.

Chemical reactor engineering, as a discipline, has a central role to play in helping with the development of adequate strategies and technologies that can deal effectively with the concerns of today's society, which are increasingly becoming attuned to the environment. The current challenge is how to adapt present processes and products to meet more rigorous environmental standards. Chemical Reactor Technology for Environmentally Safe Reactors and Products addresses these issues in three parts: I -- Fuels of the Future and Changing Fuel Needs; II -- Alternative Sources; III -- Emission Control, Chemical Reactor Safety and Engineering. Attention is also paid, throughout the text, to the fundamental technological aspects of reactor engineering and to possible strategies for bridging knowledge gaps.

All significant studies agree that aqueous corrosion continues to cost nations dearly in almost every area of technological endeavour. Over the past ten years, microcomputers have facilitated an explosion in the power of modelling as a technique in science and engineering. In corrosion they have enabled better understanding of polarization curves, they have transformed the scope of electrochemical impedance measurements and they have placed a large range of electrochemistry at the fingertips of the corrosion scientist. This book focuses on the models, rather than the computing, which have been made possible during the past decade. Aimed at all those with an interest in corrosion and its control, the book draws together the range of new modelling strands, suggests new avenues of approach and generates further momentum for improvements to corrosion management, whether by increased understanding of atomistic processes or by control of large plant.

In the ten years since the scientific rationale for the design, synthesis and application of inorganic and organometallic polymers (IOPs) was first conceptualised, we have witnessed the first tentative exploration of IOPs as precursors to new materials, with efforts focusing on the design and synthesis of novel ceramic precursors. Developing expertise led to precursor studies combined with the characterisation of the transformation processes that occur when IOPs are converted to ceramic materials. Now at maturity, the science presented in this volume reveals the polymer precursor approach to materials synthesis together with examples of processing ceramic shapes for a range of mechanical properties, the development of sophisticated, noninvasive analytical techniques, and IOP design rationales relying on well-defined processing-property relationships. The production of multifunctional IOPs is described, providing ion conductivity, gas sensing, bioactivity, magnetic properties, etc., combined with processability. The existence of well-defined IOPs and the exquisite control that can be exerted on sol-gel systems now provide access to such a variety of mixed organic-organometallic and/or inorganic hybrid systems that their exploitation is likely to develop into an entirely new field of materials chemistry. Future exciting avenues of research are also being opened up with the advent of buckyballs, Met-Cars, dopable preceramics, rigid-rod organometallics, and molecular tinkertoys.

Materials and Processes for Surface and Interface Engineering, which has been written by experts in the fields of deposition technology and surface modification techniques, offers up to date tutorial papers on the latest advances in surface and interface engineering. The emphasis is on fundamental aspects, principles and applications of plasma and ion beam processing technology. A handbook for the engineer and scientist as well as an introduction for students in several branches of materials science and surface engineering.