Composed of papers written by leading engineers and scientists in the field, this valuable collection reports the most recent advances in cryocooler development, contains extensive performance test results and comparisons, and relates the latest experience in integrating cryocoolers into advanced applications.

Proceedings of the 1991 Cryogenic Engineering Conference held in Huntsville, Alabama, June 11-14, 1991.

Lasers can readily remove very thin layers from small areas of a material and can thus be used both to control the structure of the surface and to determine its composition. Laser ablation thus has a wide variety of applications - from re-shaping the cornea of the eye to correct vision and micro-machining electronic devices, to detection of minute contaminants on catalysts. This book is the proceedings of one ofthe first workshops held on this topic.

In a liquid crystal watch, the molecules contained within a thin film of the screen are reorientated each second by extremely weak electrical signals. Here is a fine example of soft matter: molecular systems giving a strong response to a very weak command signal. They can be found almost everywhere. Soft magnetic materials used in transformers exhibit a strong magnetic moment under the action of a weak magnetic field. Take a completely different domain: gelatin, formed from col lagen fibres dissolved in hot water. When we cool below 37 DegreesC, gelation occurs, the chains joining up at various points to form a loose and highly deformable network. This is a natural example of soft matter. Going further, rather than consider a whole network, we could take a single chain of flexible polymer, such as polyoxyethylene [POE = (CH CH O)N, 2 2 5 where N rv 10 ], for example, in water. Such a chain is fragile and may break under flow. Even though hydrodynamic forces are very weak on the molecular scale, their cumulated effect may be significant. Think of a rope pulled from both ends by two groups of children. Even if each girl and boy cannot pull very hard, the rope can be broken when there are enough children pulling.

As Chairmen of the Electrochemistry and Molten Salts Discussion Groups of the Chemical Society, it gave us great pleasure to welcome the confer ence Highly Concentrated Aqueous Solutions and Molten Salts, which our Groups cosponsored, at St. John's College, Oxford in July 1978. During the meeting the editors of the present volume, and those giving lectures, came to the conclusion that the verbal presentations deserved to be expanded and to be more widely disseminated in a permanent form. Thus the articles which appear in this volume were commissioned and prepared. A greater exchange of information between aqueous chemists and those concerned with molten salts is to be welcomed and to this end the present volume aims to focus attention on the borderline areas between the two in an attempt to facilitate a wider awareness of the concepts and methods appropriate to the respective specialities. Similarly, and parti cularly in the electrochemical field, a greater exchange of information be tween the academic and industrial practitioners of the subject is desirable. T!1e problems involved are not trivial but when the interactions in these largely (but not wholly) ionic liquids are better understood, this wiii surely be to the benefit of all concerned with solution chemistry. Douglas Inman, Imperial College Chairman, Electrochemistry Group David Kerridge, University of Southampton Chairman, Molten Salts Discussion Group v Preface A number of recent events led to the appearance of this text at this particu lar time.

This volume contains the invited papers and selected contributed papers presented at the biennial International Symposium on ELECTRON COLLISIONS WITH MOLECULES, CLUSTERS AND SURF ACES held at Royal Holloway, University of London from 29th to 30th July, 1993. This Symposium was a Satellite Meeting of the XVIII International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC) and follows a 16 year tradition of Satellite Conferences in related areas of collisions held in association with previous ICPEAC's. In the past each of these electron -molecule symposia covered the broad field of electron-molecule scattering at rather low energies, but also included hot topics. This time as well as covering the whole field, well defined electron collisions with clusters and with particles in the complex potential of a surface were emphasized. Not many details are known about such collisions, although they become more and more important in surface characterisation, plasma-wall interactions, electron induced desorption and reorganisation of adsorbed particles. Recently, much work, theoretical and experimental, has been devoted to electron collisions with rather large carbon, silicon and halogen containing molecules. These problems are of relevance in plasma assisted thin film formation and etching of surfaces and can now be approached with advanced theoretical methods and experimental equipment.

This volume contains the invited papers of the Spring meeting of the Arbeitskreis Festkorperphysik of the Deutsche Physikalische Gesellschaft, which has been held in Regensburg in the period March 23 - 27, 1998. The meeting has been attended by more than 2800 participants from all areas of solid state physics and other areas of physics as well since this time it has been organized together with the yearly general meeting. The invited and plenary talks as well as the numerous symposia reflected most recent developments in physics. This book covers the current status of the fileds and shows the excitement which has been felt by the speakers when presenting their results."

Molecular similarity has always been an important conceptual tool of chemists, yet systematic approaches to molecular similarity problems have only recently been recognized as a major contributor to our understanding of molecular properties. Advanced approaches to molecular similarity analysis have their foundation in quantum similarity measures, and are important direct or indirect contributors to some of the predictive theoretical, computational, and also experimental methods of modern chemistry. This volume provides a survey of the foundations and the contemporary mathematical and computational methodologies of molecular similarity approaches, where special emphasis is given to applications of similarity studies to a range of practical and industrially significant fields, such as pharmaceutical drug design. The authors of individual chapters are leading experts in various sub-fields of molecular similarity analysis and the related fundamental theoretical chemistry topics, as well as the relevant computational and experimental methodologies. Whereas in each chapter the emphasis is placed on a different area, nevertheless, the overall coverage and the wide scope of the book provides the reader with a general yet sufficiently detailed description that may serve as a good starting point for new studies and applications of molecular similarity approaches. The editors of this volume are grateful to the authors for their contributions, and hope that the readers will find this book a useful and motivating source of information in the rapidly growing field of molecular similarity analysis.

The state-of-the-art in the theoretical statistical physics treatment of the Janus fluid is reported with a bridge between new research results published in journal articles and a contextual literature review. Recent Monte Carlo simulations on the Kern and Frenkel model of the Janus fluid have revealed that in the vapor phase, below the critical point, there is the formation of preferred inert clusters made up of a well-defined number of particles: the micelles and the vesicles. This is responsible for a re-entrant gas branch of the gas-liquid binodal. Detailed account of this findings are given in the first chapter where the Janus fluid is introduced as a product of new sophisticated synthesis laboratory techniques. In the second chapter a cluster theory is developed to approximate the exact clustering properties stemming from the simulations. It is shown that the theory is able to reproduce semi-quantitatively the micellization phenomenon.

At first glance, the articles in this book may appear to have nothing in common. They cover such seemingly disparate subjects as the properties of small metallic clusters and the behavior of superfluid He3, nuclear physics and organic materials, copper oxides and mag netic resonance. Why have they been brought together, particUlarly in our time of narrow spe cialization? In fact, the properties and effects described in this book touch upon one and the same fundamental phenomenon: pair correlation. Introduced in the theory of superconductivity by J. Bardeen, L. Cooper, and J. Schrieffer (BCS), this effect plays a key role in various Fermi systems. The book consists of several sections. The first chapter is concerned with conven tional and high Tc superconductors. The second chapter describes two relatively young fami lies of superconductors: organics and fullerenes. Chapter III addresses the superfluidity of 3 He * The discovery of this phenomenon in 1971 was a big event in physics and last year was acknowledged by a Nobel prize. This book contains the text of the Nobel lecture. Chapters IV and V are devoted to correlations in finite Fermi systems such as small metallic clusters, C 60 anions, and atomic nuclei. The book thus covers a broad range of problems, illuminating the close ties between various areas of physics.

The classical theories of Linear Elasticity and Newtonian Fluids, though trium phantly elegant as mathematical structures, do not adequately describe the defor mation and flow of most real materials. Attempts to characterize the behaviour of real materials under the action of external forces gave rise to the science of Rheology. Early rheological studies isolated the phenomena now labelled as viscoelastic. Weber (1835, 1841), researching the behaviour of silk threats under load, noted an instantaneous extension, followed by a further extension over a long period of time. On removal of the load, the original length was eventually recovered. He also deduced that the phenomena of stress relaxation and damping of vibrations should occur. Later investigators showed that similar effects may be observed in other materials. The German school referred to these as "Elastische Nachwirkung" or "the elastic aftereffect" while the British school, including Lord Kelvin, spoke ofthe "viscosityofsolids." The universal adoption of the term "Viscoelasticity," intended to convey behaviour combining proper ties both of a viscous liquid and an elastic solid, is of recent origin, not being used for example by Love (1934), though Alfrey (1948) uses it in the context of polymers. The earliest attempts at mathematically modelling viscoelastic behaviour were those of Maxwell (1867) (actually in the context of his work on gases; he used this model for calculating the viscosity of a gas) and Meyer (1874)."

Multiple scattering of waves is a rapidly growing field with many applications. The research group "Propagation of Waves in Disordered and/or Nonlinear Media" POAN brought together experts from different disciplines to write this review which covers applied mathematics, optics, acoustics, remote sensing, and seismology.

This book is an outcome of the International Workshop on Electronic Density Functional Theory, held at Griffith University in Brisbane, Australia, in July 1996. Density functional theory, standing as it does at the boundary between the disciplines of physics, chemistry, and materials science, is a great mixer. Invited experts from North America, Europe, and Australia mingled with students from several disciplines, rapidly taking up the informal style for which Australia is famous. A list of participants is given at the end of the book. Density functional theory (DFT) is a subtle approach to the very difficult problem of predicting the behavior of many interacting particles. A major application is the study of many-electron systems. This was the workshop theme, embracing inter alia computational chemistry and condensed matter physics. DFT circumvents the more conceptually straightforward (but more computationally intensive) approach in which one solves the many-body Schrodinger equation. It relies instead on rather delicate considerations involving the electron number density. For many years the pioneering work of Kohn and Sham (the Local Density Ap proximation of 1965 and immediate extensions) represented the state of the art in DFT. This approach was widely used for its appealing simplicity and computability, but gave rather modest accuracy. In the last few years there has been a renaissance of interest, quite largely due to the remarkable success of the new generation of gradient functionals whose initiators include invitees to the workshop (Perdew, Parr, Yang)."

This volume presents the proceedings of the Workshop on Momentum Distributions held on October 24 to 26, 1988 at Argonne National Laboratory. This workshop was motivated by the enormous progress within the past few years in both experimental and theoretical studies of momentum distributions, by the growing recognition of the importance of momentum distributions to the characterization of quantum many-body systems, and especially by the realization that momentum distribution studies have much in common across the entire range of modern physics. Accordingly, the workshop was unique in that it brought together researchers in nuclear physics, electronic systems, quantum fluids and solids, and particle physics to address the common elements of momentum distribution studies. The topics dis cussed in the workshop spanned more than ten orders of magnitude range in charac teristic energy scales. The workshop included an extraordinary variety of interactions from Coulombic to hard core repulsive, from non-relativistic to extreme relativistic."

The papers in this volume were presented at the Second International Conference on Unconventional Photoactive Solids held at the R&D Center of BP America September 9-12, 1985. It was part of an on-going series of conferences with the main aim of stressing the Interrelationship of solid state physics and solid state chemistry. The choice of topics covered a broad range of light-Induced solid state phenomena with particular emphasis on novel materials and/or novel phenomena. Organic solids, in particular, were emphasized as they are a natural meeting point of solid state physics and chemistry. A general trend In solid state physics Is to more complex materials (e.g. nonequilibrium glassy films, complicated unit cells, extended molecular building blocks, etc.). This trend necessitates the closer interaction between physicists and chemists. This conference reflects this trend quite dramatically. It is a new grouping together of a mix of materials, people and experimental approaches. A typical new theme pulling together this new mix can be seen in Part I. Fractals in Disordered Media. A variety of disordered media give rise to unusual temporal patterns of diffusion and reactions. The more familiar spatial patterns of self-similarity are discussed in the first article by M.F. Barnsley. Another topic pulling together a diverse group of scientists is covered in Part II. Spectral Hole-Burning. A number of leaders in this field are represented In these three papers.

The last two years have witnessed a continuation in the breakthrough shift toward pulse tube cryocoolers for long-life, high-reliability cryocooler applications. One class of pulse tubes that has reached maturity is referred to as "Stirling type" because they are based on the linear Oxford Stirling-cooler type compressor; these generally provide cooling in the 30 to 100 K temperature range and operate at frequencies from 30 to 60 Hz. The other type of pulse tube cooler making great advances is the so-called "Gifford-McMahon type. " Pulse tube coolers of this type use a G-M type compressor and lower frequency operation to achieve temperatures in the 2 to 10 K temperature range. Nearly a third of this proceedings covers these new developments in the pulse tube arena. Complementing the work on low-temperature pulse tubes is substantial continued progress on rare earth regenerator materials and Gifford-McMahon coolers. These technologies continue to make great progress in opening up the 2 - 4 K market. Also in the commercial sector, continued interest is being shown in the development of long-life, low-cost cryocoolers for the emerging high temperature superconductor electronics market, particularly the cellular telephone base-station market. At higher temperature levels, closed-cycle J-T or throttle-cycle refrigerators are taking advantage of mixed refrigerant gases to achieve low-cost cryocooler systems in the 65 to 80 K temperature range.

The Advanced Research Workshop (ARW) on Condensed Matter Re search Using Neutrons, Today and Tomorrow was held in Abingdon, Oxfordshire for four days beginning 26 March 1984. The Workshop was sponsored by NATO and the Rutherford Appleton Laboratory. A total of 32 lecturers and participants attended. An objective of the Workshop was to review some dynamic proper ties of condensed matter that can be studied using neutron spectros copy. A second objective, no less important, was to identify new topics that might be investigated with advanced spallation neutron sources. The twelve lectures reproduced in this volume bear wit ness, largely by themselves, to the success of the Workshop in meet ing these objectives. The many discussions generated by lecturers and participants meant that, in the event, the objectives were in deed amply satisfied. I should like to thank all those who attended the Horkshop for their part in making it so beneficial and rewarding. I am most grateful to Reinhard Scherm, who acted as my advisor in the organisation of the Workshop. The efforts of Mrs. M. Sherwen and Miss J. Harren made light my burden of administrative duties. The preparation of the manuscript for publication was simplified by the assistance of Miss C. Monypenny."

The last twenty years have seen major advances in the electronics industry. Perhaps the most significant aspect of these advances has been the significant role that electronic equipment plays in almost all product markets. Even though electronic equipment is used in a broad base of applications, many future applications have yet to be conceived. This versatility of electron ics has been brought about primarily by the significant advances that have been made in integrated circuit technology. The electronic product user is rarely aware of the integrated circuits within the equipment. However, the user is often very aware of the size, weight, mod ularity, maintainability, aesthetics, and human interface features of the product. In fact, these are aspects of the products that often are instrumental in deter mining its success or failure in the marketplace. Optimizing these and other product features is the primary role of Electronic Equipment Packaging Technology. As the electronics industry continues to pro vide products that operate faster than their predecessors in a smaller space with a reduced cost per function, the role of electronic packaging technology will assume an even greater role in the development of cost-effective products.

Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.

Cryocoolers 10 is the premier archival publication of the latest advances and performance of small cryogenic refrigerators designed to provide localized cooling for military, space, semi-conductor, medical, computing, and high-temperature superconductor cryogenic applications in the 2-200 K temperature range. Composed of papers written by leading engineers and scientists in the field, Cryocoolers 10 reports the most recent advances in cryocooler development, contains extensive performance test results and comparisons, and relates the latest experience in integrating cryocoolers into advanced applications.

The book aims to give an overview of the previous Sitges Conferences, which have been held during the last 25 years, with special emphasis on topics related to non-equilibrium phenomena. It includes review articles and articles dealing with new trends in the subject, written by scientists who have played an important role in the development of this area. The book is intended as a commemorative edition of the Sitges Conferences. Graduate students of physics and researchers will find this a stimulating account of the development of non-equilibrium statistical mechanics in the last years, covering a wide scope of topics: kinetic theory, hydrodynamics, fluctuation phenomena and stochastic processes, relaxation phenomena, kinetics of phase transitions, growth kinetics, and so on.

The Second International Conference on Phonon Scattering in Solids was held at the University of Nottingham from August 27th - 30th 1975. It was attended by 192 delegates from 24 countries who were accompanied by 43 members of their families. Eleven invited papers were read and 96 contributed papers; the contributed papers were in two parallel sessions. The Conference included the topics of the two International Conferences held in France in 1972, in Paris and at Ste Maxime. The Conference brought together workers concerned with many aspects of phonon scattering in solids and liquid helium. Some of the work reported were studies of the intrinsic properties of diel ectric materials such as the effects of anharmonicity, dispersion and anisotropy on phonon propagation and the conditions for the existence of zero sound and second sound modes. Work was also pres ented on various aspects of phonon interaction with free electrons in metals and semiconductors. A substantial part of the Conference was devoted to phonon spectroscopy - investigations of the energy levels of ions or neutral impurities by observing the resonant absorp tion or scattering of phonons. The materials being studied include paramagnetic and parae1ectric solids, amorphous systems in which the 'impurities' appear to be intrinsic, and semiconductors. Work was reported on the use of phonons to observe phase transitions; in some cases the cooperative phase also arises through strong spin phonon coupling. One of the intriguing unsolved problems discussed in detail at the Conference is the Kapitza conductance problem."