Since the discovery of the first liquid crystal in 1888 by the Austrian biologist Friedrich Reinitzer with the considerable assistance of the German physicist Otto Lehman, who in that time had been universally recognised authority in the field of microscope technique, thousands and thousands of liquid crystals have been synthesised among them nematics, short-pitch cholesterics and various kinds of smectics such as smectic-A and smectic-C. The smectic-A or smectic-C phases grow from a nematic or unwinded large-pitch cholesteric oriented in the middle part of the cells and from strongly-deformed nematic or unwinded large-pitch cholesteric layer in the boundary regions of the liquid crystal cells.

Hydrothermal crystal growth offers a complementary alternative to many of the classical techniques of crystal growth used to synthesise new materials and grow bulk crystals for specific applications. This specialised technique is often capable of growing crystals at temperatures well below their melting points and thus potentially offers routes to new phases or the growth of bulk crystals with less thermal strain. Borate crystals are widely used as nonlinear optical, laser and luminescent materials due to their diversified structures, and good chemical and physical properties. The growth of high-quality borate crystals is required for their applications. A fundamental problem for borate crystal growth is the high-temperature melt structures in the crystal growth systems. This book discusses several crystals and the crystal growth processes.

In this book, the authors present current research in the study of the crystallography, chemistry and catalytic performance of perovskites. Topics discussed include the defect structure and defect-induced expansion of perovskite oxides; perovskite-based catalysts for transformation of natural gas and oxygenates into syngas; Bi containing multiferroic perovskite oxide thin films; perovskites as catalysts for environmental remediation; microwave-assisted synthesis and characterisation of perovskite oxides; perovskite and lead based ceramic materials; photocatalytic properties of perovskite-type layered oxides; structure of perovskite electron-ionic conductors; and distorted perovskites.

Self-sufficient and user-friendly, this book provides a complete introduction to the anisotropic elasticity theory necessary to model a wide range of crystal defects. Assuming little prior knowledge of the subject, the reader is first walked through the required basic mathematical techniques and methods. This is followed by treatments of point, line, planar and volume type defects such as vacancies, dislocations, grain boundaries, inhomogeneities and inclusions. Included are analyses of their elastic fields, interactions with imposed stresses and image stresses, and interactions with other defects, all employing the basic methods introduced earlier. This step by step approach, aided by numerous exercises with solutions provided, strengthens the reader's understanding of the principles involved, extending it well beyond the immediate scope of the book. As the first comprehensive review of anisotropic elasticity theory for crystal defects, this text is ideal for both graduate students and professional researchers.

The three-dimensional aspects of molecular shape can be crucial to both properties and reactions. The Third Dimension explores the arrangements of atoms in molecules and in different types of solids. Initial chapters describe the common crystal structures and how they are related to close-packed arrangements of ions. Metallic, ionic, molecular and extended covalent crystals are covered; major types of crystal defects are also discussed. The book then introduces isomerism, and explores the stereochemical consequences of the tetrahedral carbon atom. Chirality is also investigated. The book concludes with a Case Study on Liquid Crystals, which describes structures, properties and applications. As visualisation in 3D is an important part of this book, the accompanying CD-ROMs provide video material, interactive questions and exercises using models to aid understanding of crystals, organic molecules and stereochemistry. All necessary programs are provided. The Molecular World series provides an integrated introduction to all branches of chemistry for both students wishing to specialise and those wishing to gain a broad understanding of chemistry and its relevance to the everyday world and to other areas of science. The books, with their Case Studies and accompanying multi-media interactive CD-ROMs, will also provide valuable resource material for teachers and lecturers. (The CD-ROMs are designed for use on a PC running Windows 95, 98, ME or 2000.)

This book deals with the phenomenological theory of first-order structural phase transitions, with a special emphasis on reconstructive transformations in which a group-subgroup relationship between the symmetries of the phases is absent. It starts with a unified presentation of the current approach to first-order phase transitions, using the more recent results of the Landau theory of phase transitions and of the theory of singularities. A general theory of reconstructive phase transitions is then formulated, in which the structures surrounding a transition are expressed in terms of density-waves, providing a natural definition of the transition order-parameters, and a description of the corresponding phase diagrams and relevant physical properties. The applicability of the theory is illustrated by a large number of concrete examples pertaining to the various classes of reconstructive transitions: allotropic transformations of the elements, displacive and order-disorder transformations in metals, alloys and related structures, crystal-quasicrystal transformations.

Epigenetic Technological Applications is a compilation of state-of-the-art technologies involved in epigenetic research. Epigenetics is an exciting new field of biology research, and many technologies are invented and developed specifically for epigenetics study. With chapters covering the latest developments in crystallography, computational modeling, the uses of histones, and more, Epigenetic Technological Applications addresses the question of how these new ideas, procedures, and innovations can be applied to current epigenetics research, and how they can keep pushing discovery forward and beyond the epigenetic realm.

Chemical crystallography is the study of the principles of chemistry behind crystals and their use in describing structure-property relations in solids. The principles that govern the assembly of crystal and glass structures are described, models of many of the technologically important crystal structures are studied, and the effect of crystal structure on the various fundamental mechanisms responsible for many physical properties are discussed. This new book presents and reviews data on the co-ordination chemistry of several metal complexes with dipicolinic acid and the crystal structure of some anti-malarial metal complexes.

Fibre (rod) and sheet-shaped crystals with specified size for use as final products without additional machining are required in various applications of modern engineering. In order to avoid formation of internal mechanical stress in the crystal, lateral surface shaping without contact with container walls is preferred. As the crystal is not restricted by crucible walls, its cross-section is determined by the meniscus-shaping capillary forces and the heat and mass-exchange in the melt-crystal system. Any variation of the pulling rate, pressure, temperature gradient in the furnace, and melt temperature at the meniscus base leads to a change in the crystal cross-section and to pinch formation. Over the past two decades, many experimental and theoretical studies have been reported on a powerful approach to crystal lateral surface shaping without contact with container walls, namely the so-called edge-defined film-fed growth (EFG) technique. The shape and size of a single crystal grown by EFG is determined by the shape and size of the meniscus, (i.e: the liquid bridge retained between the die and the crystal) which depend on the radius or half-thickness of the die and other properties such as pulling rate, pressure, temperature gradient and melt temperature. In this book, theoretical and numerical results are obtained using a non-linear mathematical model of the EFG method. Theoretical results presented for fibres and sheets are rigorously obtained on the basis of the equations of the model. Numerical results are obtained on the basis of theoretical results using experimental data. Such results offer a complete package of the possibilities of the model for equipment designers and practical crystal growers.

New Developments In Crystal Growth

This book is intended as an easy to read supplement to the often brief descriptions of hydrogen bonding found in most undergraduate chemistry and molecular biology textbooks. It describes and discusses current ideas concerning hydrogen bonds ranging from the very strong to the very weak, with introductions to the experimental and theoretical methods involved.

The last ten years have seen a revolution in our understanding of the mechanisms of biological crystal growth. While it had long been assumed that crystallisation would occur by the same classical mechanisms which form the basis for most descriptions of crystallisation processes, it is now becoming apparent that this is not the case. There are a number of key observations which have changed our view of crystallisation mechanisms. While it had long been assumed that crystalline biominerals typically form by ion-by-ion growth, it is now recognised that they often precipitate via amorphous precursor phases. This is well established for calcium carbonate and there is growing evidence that biogenic crystalline calcium phosphate phases may form via an analogous route. Recent re-examination of the structure of many calcium carbonate biominerals is also suggesting that "non-classical" crystallisation pathways, where crystals grow from the assembly of precursor particles, may also be widespread. Significantly, these mechanisms are not unique to the biological world. Possibly partly inspired by the identification of these biogenic mineralisation strategies, there is currently great interest from the general crystal growth community in these new and controversial ideas. A number of studies on crystal nucleation have recently re-examined classical nucleation theory, and the observation of pre-nucleation clusters is a recurrent theme of great interest. This controversial result apparently contradicts classical nucleation theory which leads the subject of crystal nucleation and growth via assembly to demand attention. The Scientific Committee warmly invites you to take part in this thought-provoking Discussion and looks forward to welcoming you to Leeds.

In recent years, there has been increasing activity in the research and design of optical systems based on liquid crystal (LC) science. Bringing together contributions from leading figures in industry and academia, Optical Applications of Liquid Crystals covers the range of existing applications as well as those in development. Unique in its thorough coverage of applications, not just the basic chemistry and physics of liquid crystals, the book begins with the existing applications of liquid crystals, from the ubiquitous LCD through to LC projectors and holography. The remaining chapters discuss more promising technologies in development, including photoaligning, photopatterning, and bistable twisted nematic LCs.