Uorganisk kemi

Micro Electro Mechanical Systems (MEMS) is already about a billion dollars a year industry and is growing rapidly. So far major emphasis has been placed on the fabrication processes for various devices. There are serious issues related to tribology, mechanics, surfacechemistry and materials science in the operationand manufacturingof many MEMS devices and these issues are preventing an even faster commercialization. Very little is understood about tribology and mechanical properties on micro- to nanoscales of the materials used in the construction of MEMS devices. The MEMS community needs to be exposed to the state-of-the-artoftribology and vice versa. Fundamental understanding of friction/stiction, wear and the role of surface contamination and environmental debris in micro devices is required. There are significantadhesion, friction and wear issues in manufacturing and actual use, facing the MEMS industry. Very little is understood about the tribology of bulk silicon and polysilicon films used in the construction ofthese microdevices. These issues are based on surface phenomenaand cannotbe scaled down linearly and these become increasingly important with the small size of the devices. Continuum theory breaks down in the analyses, e. g. in fluid flow of micro-scale devices. Mechanical properties ofpolysilicon and other films are not well characterized. Roughness optimization can help in tribological improvements. Monolayers of lubricants and other materials need to be developed for ultra-low friction and near zero wear. Hard coatings and ion implantation techniques hold promise.

Dr. Heinonen reviews and critically evaluates the scientific literature on the biological role of inorganic pyrophosphate (PPi ) published from 1940 to the end of 1999. He describes and classifies all known biochemical reactions that produce Ppi; describes and evaluates all published methods used in biological Ppi; and compiles and critically evaluates information on the concentration of PPi (with the conclusion that, contrary to common belief, PPi exists throughout the living world in rather high concentrations). Many reactions in which PPi is used as a biochemical energy source instead of ATP have been described in recent decades, especially in bacteria, protists, and plants. These reactions are evaluated from the bioenergetic and regulatory points of view. Also considered is the possible role of PPi as a source of biochemical energy in the primitive phases of life, before ATP. Data is presented on the regulatory role of PPi in living systems, such as activities of enzymes, fidelity of syntheses of macromolecules, and proliferation of cells. PPi may also regulate the formation and dissolution of bone as well as pathologic calcification of soft tissues and the formation of urinary stones. The formation of calcium pyrophosphate dihydrate crystals in the extracellular fluids of joints cause the disease called pseudogout. Biological Role of Inorganic Pyrophosphate book is a unique and invaluable source of references (about 1120) and summarized data for professionals who study or plan to study the role of PPi in living systems. Many different branches of science (biochemistry, microbiology, bioenergetics, plant physiology, parasitology, evolution, orthopedics, rheumatology) have involvement with PPi. This book sums up available knowledge in one place and will help scientists cross disciplinary boundaries.

Polymer science is a technology-driven science. More often than not, technological breakthroughs opened the gates to rapid fundamental and theoretical advances, dramatically broadening the understanding of experimental observations, and expanding the science itself. Some of the breakthroughs involved the creation of new materials. Among these one may enumerate the vulcanization of natural rubber, the derivatization of cellulose, the giant advances right before and during World War II in the preparation and characterization of synthetic elastomers and semi­ crystalline polymers such as polyesters and polyamides, the subsequent creation of aromatic high-temperature resistant amorphous and semi-crystal­ line polymers, and the more recent development of liquid-crystalline polymers mostly with n~in-chain mesogenicity. other breakthroughs involve the development of powerful characterization techniques. Among the recent ones, the photon correlation spectroscopy owes its success to the advent of laser technology, small angle neutron scattering evolved from n~clear reactors technology, and modern solid-state nuclear magnetic resonance spectroscopy exists because of advances in superconductivity. The growing need for high modulus, high-temperature resistant polymers is opening at present a new technology, that of more or less rigid networks. The use of such networks is rapidly growing in applications where they are used as such or where they serve as matrices for fibers or other load­ bearing elements. The rigid networks are largely aromatic. Many of them are prepared from multifunctional wholly or almost-wholly aromatic kernels, while others contain large amount of stiff difunctional residus leading to the presence of many main-chain "liquid-crystalline" segments in the "infinite" network.

Ever since the first volume appeared in 1969, this series has received good reviews in a variety of periodicals published in different corners of the world. It would seem that the work has fulfilled its purpose as outlined in the Preface to Volume 1. The rapidly increasing interest in surface and colloid science by people engaged in industrial research and development, and in environmental, ecological, medical, pharmaceutical, and other areas, justifies the continuation of such an effort. The Surface and Colloid Science series originated with John Wiley and Sons and has been continued with Plenum Press. This volume is the third with the present publisher, and is the best assurance of our mutual interest to proceed with this work. Some books in the series, as was the case with Volume 11, may appear under the editorship of other workers in the field. For reasons of continuity, a sequential numbering system will be maintained. This editor hopes to provide the scientific and technical community with high-quality contributions in surface and colloid science in the future. He invites specialists to submit definitive chapters on any topic within the broad area of our discipline for inclusion in this series.

This book represents the proceedings of the First International Conference on Frontiers of Polymer Research held in New Delhi, India during January 20-25, 1991. Polymers have usually been perceived as substances to be used in insulations, coatings, fabrics, and structural materials. Defying this classical view, polymers are emerging as a new class of materials with potential applications in many new technologies. They also offer challenging opportunities for fundamental research. Recognizing a tremendous growth in world wide interest in polymer research and technology, a truly global "1st International Conference on Frontiers of Polymer Research" was organized by P. N. Prasad (SUNY at Buffalo), F. E. Karasz (University of Massachusetts) and J. K. Nigam (Shriram Institute for Industrial Research, India). The 225 participants represented 25 countries and a wide variety of academic, industrial and government groups. The conference was inaugurated by the Prime Minister of India, Mr. Chandra Shekhar and had a high level media coverage. The focus of the conference was on three frontier areas of polymer research: (i) Polymers for photonics, where nonlinear optical properties of polymers show great promise, (ii) Polymers for electronics, where new conduction mechanisms and photophysics have generated considerable enthusiasm and (iii) High performance polymers as new advanced polymers have exhibited exceptionally high mechanical strength coupled with light weight.

This monograph consists of the proceedings of the Fifth International Symposium on the Activation of Dioxygen and Homogeneous Catalytic Oxidation, held in College Station, Texas, March 14-19, 1993. It contains an introductory chapter authored by Professors D. H. R. Barton and D. T. Sawyer, and twenty-nine chapters describing presentations by the plenary lecturers and invited speakers. One of the invited speakers, who could not submit a manuscript for reasons beyond his control, is represented by an abstract of his lecture. Also included are abstracts of forty-seven posters contributed by participants in the symposium. Readers who may wish to know more about the subjects presented in abstract form are invited to communicate directly with the authors of the abstracts. This is the fifth international symposium that has been held on this subject. The first was hosted by the CNRS, May 21-29, 1979, in Bendor, France (on the Island of Bandol). The second meeting was organized as a NATO workshop in Padova, Italy, June 24-27, 1984. This was followed by a meeting in Tsukuba, Japan, July 12-16, 1987. The fourth symposium was held at Balatonfured, Hungary, September 10-14, 1990. The sixth meeting is scheduled to take place in Delft, The Netherlands (late Spring, 1996); the organizer and host will be Professor R. A. Sheldon.

This volume chronicles the proceedings of the Third Symposium on Metallized Plastics: Fundamental and Applied Aspects held under the auspices of the Dielectric Science and Technology Division of the Electrochemical Society in Phoenix, Arizona, October 13-18, 1991. This series of symposia to address the subject of metallized plastics was initiated in 1988 and the premier symposium was held in Chicago, October 10-12, 1988, followed by the second event in Montreal, Canada, May 7-10, 1990. The rroceedings of these two symposia have been properly documented ,2. The third symposium was a huge success like the previous two events, and all this is testimonial to the brisk interest and high tempo of R&D activity in the fie14 of metallized plastics. This further bolsters our earlier thinking that there was a conspicuous need to hold symposia on this topic on a regular basis and the fourth is planned for May 16-21, 1993 in Honolulu, Hawaii. The study of metallized plastics constitutes an important human endeavor l and as pointed out earlier there are myriad applications of metallized plastics ranging from very commonplace to exotic. Also a survey of the recent literature will reveal that both the fundamental and applied aspects of metallized plastics are being pursued with great vigor.

The term biotechnology has emerged on the contemporary scene fairly recently, but the basic concept of utilizing natural materials, either directly or in modified versions, dates back to antiquity. If we search the ancient literature, such as the Bible, we find hundreds of examples wherein people employed, or modified, natural materials for a variety of important uses. As far back as the days of Noah we find pitch, a natural material, being used as a caulk. Clothing was made from animal skins and the products of several plants. Today, we would consider these things as important biotechnological developments. Likewise, the human use of polymeric materials also has a long his­ tory. In fact, many of the original materials used by mankind were poly­ mers derived from nature, such as wood, flax, cotton, wool and animal skins, which were used for shelter and clothing. In recent years, however, the concept of biotechnology has taken on a new and renewed role in our society. This is due to a combination of factors, including an increased interest in environmental concerns and the desire to break free from the stranglehold that petrochemicals have placed on our society. If we can manufacture some of our polymers from renewable resources, then we can expect to prepare them for many more years into the future than we might if we could only depend on the petro­ chemical resources.

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.

In der umfassend erweiterten 2. Auflage stellen die Autoren neben den grundlegenden Konzepten der Molekülsymmetrie nun auch Symmetrieuntersuchungen in Festkörpern mittels der Röntgendiffraktometrie vor. Damit werden Symmetrieoperationen, Punkt- und erstmalig auch Raumgruppen neben Schwingungs- und Elektronenspektroskopie sowie kernmagnetische Resonanz behandelt.

Dieses moderne Lehrbuch hebt sich von den Standardlehrbüchern ab. Das Gerüst der Lerneinheiten bilden dabei die wichtigsten Prinzipien der Anorganischen Chemie wie Symmetrie, Koordination und Periodizität. Die Stoffchemie wird zur Darstellung und Verdeutlichung hinzugezogen. Zahlreiche neue Abbildungen, ein neues Layout und viele Übungsaufgaben nach jedem Kapitel vervollständigen die Neuauflage.

This book contains most, but regrettably not all, the papers that were presented at the Advanced Research Study Institute, ASI, held at the Fantasia Hotel, Kusadasi, Turkey, July 26 - August 8, 1998. A powerful incentive to the development of vortex physics in superconductors, that has began with Abrikosov Vortices in Shubnikov's Mixed State, was realized after the discovery of the high-Tc superconductivity. Indeed, a number of the most intriguing phenomena and states of the flux line lattice are observed in high-Tc superconducting materials due to their high anisotropy, intrinsically layered crys­ tal structure, extremely small coherence length and the possibility of coexistence of superconducting vortex states with high-energy thermal fluctuation. These pe­ culiarities are demonstrated as the 2D flux line lattice of point-vortices (pan­ cakes), Josephson vortices or strings in parallel and/or tilted magnetic fields, flux line lattice melting into vortex liquid and its freezing into vortex "solid" (e. g. , crystal-or glass-like) state. It is well known, that the main reason for conditioning of the vortex ensemble state and behavior (except the extrinsic factors, such as applied magnetic field or temperature) is a set of intrinsic/extrinsic superconduct­ ing material properties caused by the crystal nature and symmetry, atoms ar­ rangement, anisotropy, as well as by the spectrum of crystal defects, their dimen­ sions, arrangement and density.

This book by Kaplan and Vekhter brings together the molecular world of the chemist with the condensed matter world of the physicist. Prior to the collapse of the Soviet Union, chemists in the West devoted lit­ to relationships between molecular electronic structure and tle attention solid-state vibronic phenomena. Treating quantum mechanical problems wherein the adiabatic Born-Oppenheimer approximation fails was done by "brute force. " With bigger and better computers available in the West, molecular orbital calculations were done on observed and conceived static structures with little concern for any cooperativity of vibrational behavior that might connect these states. While it had long been understood in the West that situations do occur in which different static structures are found for molecules that have identical or nearly identical electronic structures, little attention had been paid to understanding the vibrational states that could connect such structures. It was easier to calculate the electronic structure observed with several possible distortions than to focus on ways to couple electronic and vibrational behavior. In the former Soviet Union, computational power was not as acces­ sible as in the West. Much greater attention, therefore, was devoted to conserving computational time by considering fundamental ways to han­ dle the vibrational connectivity between degenerate or nearly degenerate electronic states.

This book is devoted to general questions of the chemistry of metal alkoxides - including physiochemical properties, structure, specific features of single groups of alkoxides, theoretical principles of their use, and major applications of this method in the preparation of functional materials.

This handy bilingual (German/English) reference work provides a clear overview of European steel designations. Steel grades can be referenced according to material number or by old or new designations. The 4th edition of this handy guide to European steel grades has been expanded and fully updated to reflect changes in the relevant European standards. It contains: a detailed overview of the designation system // English and German lists comparing old and new designations // Tables of scope of use.

With information that will remain valid for years, this series presents critical reviews of the present position and future trends in modern research into chemical structure and bonding. It features concise reports, each written by world-renowned experts.