bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grain Boundary Chemistry and Reactions in Metals
Authors: Briant C.L. 
Published: August 2016

An interface can be defined as a surface that serves as a common boundary between two phases. Examples include the boundaries between two solids, two immiscible liquids, a solid and a liquid, a solid and a gas, and a liquid and a gas. Interfaces have been studied for decades by scientists of many different disciplines. One reason for this interest is that the atomic structure and the chemical composition at the interface can differ from that of the bulk material on either side of it. Consequently, the properties of the interface can differ greatly from those of either bulk phase, and chemical reactions can occur more readily at the interface than in the bulk.All the interfaces listed in the previous paragraph are of interest to materials scientists. However, this article will only consider the grain boundary because it has received the most attention by researchers in materials science. Furthermore, we will only consider grain boundaries in metals; nonmetallic systems will be covered in other articles in this issue.A grain boundary is an interface that exists where two single crystals are joined in such a way that their crystallographic orientations are not completely matched. Thus, any polycrystalline material contains many grain boundaries. They occur wherever the individual grains meet one another and can usually be observed by etching a polished cross section of the surface as shown in Figure 1. Grain boundaries first form in a metal as a result of the multiple nucleation sites that occur during solidification.
The Emerging Undergraduate Curricula in Materials Science and Engineering
Authors: Liedl G.L. 
Published: August 2016

Much attention has again been brought to the question of undergraduate education for the “materials” field. The present reawakening relates to the release last fall of the report by the National Research Council's Committee on Materials Science and Engineering. This far-ranging study, popularly known as the MS&E Study, revealed the vitality, opportunities, challenges, and needs in materials science and engineering for the future. Education was one area that received much attention in this study because it is the enabling aspect for the field: no educated, trained personnel — no progress.When one considers the breadth of materials science and engineering, the problem of designing a unique undergraduate program becomes a major hurdle. The diversity of the field is, on one hand, a major asset in addressing problems but, on the other, a major obstacle to unifying an educational approach. This problem is not new since we have faced it over time as information and knowledge expands. However, the problem becomes magnified as the time frame for the doubling of information decreases. The explosion of information over the past half-century has drastically altered our outlook on materials, and the educational programs have been evolving with the changes. We are now at one of those crossroads where revolution versus evolution becomes a factor, i.e., the need to change basic philosophy and/or approach becomes the issue. If one doesn't consider a breakdown of the current materials classes into subgroups, then a reunification approach becomes not only desirable but absolutely necessary.
The Undergraduate Physics and Materials Science Connection
Authors: Holcomb D.F. 
Published: August 2016

Materials science is fundamentally an interdisciplinary field. For purposes of discussing undergraduate preparation for work in materials science, I think it useful to take chemistry, physics, and materials science and engineering as three more-or-less separate disciplines which combine to form the overall field of materials science. The primary reason for this particular taxonomy is pragmatic rather than philosophical. Undergraduate students choose major fields of study on the basis of disciplinary boundaries. Thus, in thinking about undergraduate preparation for work in the overall field, analysis of the present situation and/or recommendations for change must revolve around that reality.The recent report entitled Materials Science and Engineering for the 1990s (the MS&E Study), sets forth the four elements of materials science and engineering as “structure and composition, properties, performance, and synthesis and processing.” An examination of these specific elements permits us to make useful distinctions among the three disciplines that combine to form the field of materials science. For example, while input from the point of view of physics certainly can contribute rather directly to expansion of our knowledge in the first three areas, its possible contribution to the last is, at best, indirect. To somewhat belabor the point, the research field of condensed matter physics is certainly contained within the field of materials but arguably not part of the discipline of materials science and engineering.The MS&E Study includes a chapter entitled “Manpower and Education in Materials Science and Engineering.” Within that chapter is a section called “Undergraduate Education in Materials Science and Engineering.”
Developments and Applications for All-Aluminum Alloy Vacuum Systems
Authors: Ishimaru Hajime 
Published: August 2016

Aluminum and aluminum alloys have long been among the preferred materials for ultrahigh vacuum (UHV) systems operating in the 10−10–10−11 torr (10−8–10−11 Pa) range. Pure aluminum and aluminum alloys have an extremely low outgassing rate, are completely nonmagnetic, lack crystal structure transitions at low temperatures, are not sources of heavy metals contamination in semiconductor processing applications, have low residual radioactivity in radiation environments, and are lightweight. Because of aluminum's high thermal conductivity and low thermal emissivity, aluminum components can tolerate high heat fluxes in spite of the relatively low melting point of aluminum.Recently developed aluminum alloys and new surface finishing techniques allow the attainment of extremely high vacuums (XHV) in the 10−12–10−13 torr (10−10–10−11 Pa) range. XHV technology requires the use of special aluminum alloy flange/gasket/bolt, nut and washer combinations, aluminum alloy-ceramic seals, windows, bellows, right-angle and gate valves, turbomolecular pumps, sputter ion pumps and titanium sublimination pumps, Bayard-Alpert ion gauges, quadrupole mass filters, and related aluminum alloy vacuum components. New surface treatment methods and new techniques in welding and extremely sensitive helium leak testing are required. In short, a whole new technology has been developed to take advantage of the opportunities presented by these new vacuum materials. This article describes some of these newly developed fabrication technologies and vacuum materials.The TRISTAN electron-positron collider constructed at the National Laboratory for High Energy Physics in Japan is the first all-aluminum alloy accelerator, and the first to use UHV technology.
The Electronic Structure of High Tc Copper-Oxide Superconductors from Photoemission Spectroscopy
Authors: Allen J.W. , Olson C.G. 
Published: August 2016

This article will summarize the information gained from photoemission spectroscopy (PES) studies of the electronic structure of high temperature superconductor (HTSC) materials, with emphasis on distinguishing models for the normal state. Inverse photoemission spectroscopy (IPES) is a closely related measurement, and taken together PES and IPES yield the single-particle electronic structure, meaning the the spectrum to remove and add electrons, i.e., the electronic ionization and affinity spectrum. It is assumed that the sudden approximation holds, so that the photon event can be characterized by a photoemission cross section σ. The emission from a particular kind of electronic state i can often be identified because its cross section has a particular photon energy (hv) dependence σ (hv).We will emphasize a few recent results especially pertinent to the conceptual issues posed by these materials, and we will divide the discussion between angle-integrated spectra and angle-resolved spectra. For angle-integrated spectra, electrons are collected from the sample surface in a large solid angle, while for angle-resolved spectra, electrons are collected in a well-defined direction. Angle resolution can be used to select emitted electrons of a particular value of crystal momentum k.
Infrared Studies of the Superconducting Energy Gap and Normal State Dynamics of Y1Ba2Cu3O7 and Ba0.6K0.4BiO3
Authors: Schlesinger Z. , Collins R. T. 
Published: August 2016

The discovery by Bednörz and Müller of superconductivity in La20xBaxCuO4 initiated an intense and fruitful search for additional perovskite-based superconducting compounds. Following the discovery and characterization of a number of important new compounds, and the development of techniques to produce them in pure crystalline form, it becomes relevant to carefully measure the fundamental physical properties of well-characterized samples of these new materials. Ultimately the goal of this work is to illuminate the basic physics of these novel materials.Traditionally many techniques, including critical field measurements, specific heat, penetration depth, magnetic resonance, and tunneling and infrared spectroscopies, have been useful for the study of superconducting elements and compounds. This article discusses the use of infrared measurements to study both cubic BaBiO3 based compounds and layered cuprates. We emphasize the work on the (ideally) stochiometric compound Y1Ba2Cu3O7, because its infrared properties have been obtained by a number of groups with good reproducibility. Infrared measurements are useful both in terms of their traditional role as a probe of the superconducting energy gap and for their ability to probe the dynamics of the normal state by measuring the conductivity vs. frequency in the crucial infrared range (~1 meV to 2 eV).
Materials Challenges in Integrated Optical Recording Heads
Authors: Weller-Brophy Laura A. , Zelinski Brian J.J. , Birnie Dunbar P. 
Published: August 2016

Integrated optical recording head concepts show promise for future light-weight and compact optical heads. Several fundamental issues remain to be explored before fully integrated optical heads. become a reality. This article reviews the basic operating principles of integrated optic heads, focusing on the materials challenges inherent in developing both partially and fully integrated optical heads.Currently available optical mass storage systems provide a feature unavailable in magnetic direct access storage devices (DASD) — removable and interchangeable media. At present, however, this feature is bought at a price, with magnetic storage devices currently outperforming their optical counterparts in access speed and volumetric storage density. The access time of optical drives is greater than 40 ms, compared to the 10–20 ms typical of magnetic DASD. This is, in large part, a consequence of the 50–100 g moving mass of the optical head. The optical head also limits the maximum volumetric storage density, with current heads ranging from about 0.5 cm to more than 2 cm in height.
Birefringence Properties of Polymeric Substrate Materials
Authors: Pisipati Ramesh M. , Schmid Helmut , Kämpf Günther 
Published: August 2016

Depending upon the nature of the application, three materials currently dominate the optical substrate market today. Polycarbonate (PC), the most commonly used material, is typically used in disks with diameters up to 120 mm. For larger diameters, the inherent birefringence exhibited by PC interacts with the read laser and results in errors in the read-back signal. For 200 mm and greater, both polymethylmethacrylate (PMMA) and glass are used. Because PMMA is low in inherent birefringence, it is widely used for 200 mm video disks, an application which takes advantage of the manufacturing economies of the injection molding process. For larger diameter data storage disks, however, glass is used because it does not have the disadvantage of relatively high moisture absorption or the low heat resistance of PMMA.This article will deal with the state-of-the-art in materials used for polymeric substrates. It will focus primarily on polycarbonate and the most significant substrate property currently confronting the field, namely birefringence. Other constraints placed by optical storage technology on the substrate material will be discussed along with new materials and research activities aimed at circumventing some of the current limitations.
Trends in Optical Disk Mastering
Authors: Put Paul L.M. 
Published: August 2016

The commercial life of optical disks started in the late 1970s with prerecorded, read-only video disks. The video information was stored on the disks in the form of pits with varying lengths aligned in a spiral track, a structure which lends itself to easy mass replication. The pits were recorded in a “master” disk by exposing a positive photoresist to a focused beam of blue or UV light from a gas laser and subsequently developing the resist. Now, some 15 years later, mass-replicated, read-only video and audio disks still form the most important application of optical disk technology. Today a large majority of the corresponding masters are recorded using virtually the same technique.In view of the relative importance of prerecorded disks, it is amazing that so little seems to have changed in the mastering processes. Part of the explanation lies in the fact that the dimensions of the relief structures on the early optical disks were defined by what a player could read using relatively cheap optics, rather than by what could be made in the mastering process. If in the beginning the analog video disk system (Video Long Play or LaserVision) was rather demanding, the digital audio disk (compact disk) (see Figure 1a), introduced later, was a much easier system from a mastering point of view. In that period a trend toward cheaper and faster mastering techniques developed, resulting in a few proposals for direct-effect and direct metal mastering. However, in the meantime very high-quality mastering became necessary for the CD-video system and for preformatted data disks. In the CD-video system, the combination of digital audio and analog video leads in some cases to pits as short as 300 nm (see Figure 1b). On preformatted data disks, wide shallow grooves may have to be combined with narrow deep header pits (Figure 1c).
Magnetic Recording Materials: Present and Future
Authors: Berkowitz Ami 
Published: August 2016

For more than 40 years, magnetic recording has been the dominant technology for electronic data storage. During this time, the areal storage density on disks has risen to >108 bits/cm2. On tapes the corresponding figure is 0.2 × 108 bits/cm2. Thus each bit uses about a 1.0 μm2 area. These bits are written and read at data rates that require head-disk relative speeds of tens of meters per second and head-tape relative speeds of several meters per second. All this is accomplished at head-disk spacings of ≈0.2 μm and with contact recording for tapes.It is truly a wonder that the systems work as well as they do. In fact, for many features in magnetic recording systems it isn't certain why they work as well as they do. However, the demand for storage capacity is estimated to be increasing at about 40% per year. So it is natural to ask whether magnetic recording can maintain its present dominant position in the foreseeable future. The answer is — “Very likely, yes” — but this prediction is based on the assumption that a number of formidable fascinating problems will be solved in order to increase the areal bit density.The five articles in this special issue present the state-of-the-art in those key areas of magnetic recording that involve materials science, and they define the problems involved in increasing storage density. James U. Lemke discusses the background and outlook for magnetic recording.
Multilayer Optics for the Soft X-Ray and Extreme Ultraviolet
Authors: Barbee Troy W. 
Published: August 2016

This article considers a particular class of optic microstructure — multilayers for soft x-ray (SXR, 100 eV[124 Å] to 3,000 eV[4.1 Å] and extreme ultraviolet (EUV, 15 eV[800 Å] to 100 eV[124 Å] optics. Multilayers are manmade vapor-deposited depth-periodic layered micro-stractures of high enough quality to be considered synthetic crystals. Layers of two materials, A and B, having significant differences in their scattering powers for x-rays (electron densities) and of uniform thicknesses ta and tb are combined to form a sample of uniform in-depth period d0 ( = ta + tb). These microstructures are of scientific and technological significance since the high angle of incidence SXR and EUV reflectivities of single film reflectors is ~10−4) and since only a limited number of naturally occurring or synthetic large lattice constant materials efficiently diffraction reflect long wavelength radiation (SXR and EUV).Multilayer microstructure based SXR and EUV optics are direct analogues to standard quarterwave stacks applied at longer wavelengths with the requirement that absorption must be included. They are also analogous to atomic crystalline lattices in that one multilayer period is equivalent to one lattice plane. Thus, the multilayer structure forms a superlattice that diffraction reflects incident radiation. Multilayer diffraction may be modeled using x-ray scattering theory and obeys the refraction-corrected Bragg's law of crystal lattice diffraction. As will be discussed later, many factors determine the character of the multilayer response to an incident spectrum.
Up Close: Center for Advanced Materials Processing at Clarkson University
Authors: Ellis Sonia K. , McNamara Edward P. 
Published: August 2016

The Center for Advanced Materials Processing (CAMP) was established in 1985 by Clarkson University in Potsdam, New York. At that time, nearly half of the research at Clarkson was materials-related but was conducted in seven separate departments of science and engineering. To coordinate and encourage this strong materials program, CAMP was created as an interdisciplinary center dedicated to research on high-technology materials processing.The current corporate sponsors of CAMP are Corning Incorporated, Eastman Kodak, Xerox Corporation, and IBM. These and over 30 other industrial members support individual research projects. In 1987 the New York State Science and Technology Foundation designated CAMP as the New York State Center for Advanced Materials Processing, entitling CAMP to $1 million per year in operating funds. In addition, CAMP is supported by federal and University sources.In its role as an education and research initiative, CAMP has three goals:1. Enhance Clarkson University's expertise and reputation as a center of excellence in materials processing research.2. Greatly increase the mutually beneficial relationships between industrial organizations and the University; and3. Strengthen graduate and undergraduate education in materials processing.Innovative research by Egon Matijević, Distinguished University Professor, has contributed greatly to the development of the fundamental principles for the formation and interactions of colloidal dispersions. Using Matijević's work as a foundation, CAMP has developed four programs in high-technology materials research: electronic materials processing, fine-particle processing, particulate control in process equipment, and polymer processing.
Fine Particles: Science and Technology
Authors: Matijević Egon 
Published: August 2016

Some readers may wonder about the reasons for having two issues focus on fine particles. Hopefully, this introduction and the articles to follow will offer the necessary justification.It is fully expected by everybody, professional or laie, that the properties of matter will change if its chemical composition is altered. It is less frequently recognized that many characteristics of materials can be dramatically affected by varying dimensions, yet countless examples in everyday life clearly demonstrate such phenomena. Consider water in droplet form. Driving in rain creates little problem, providing the car has working windshield wipers. In contrast fog, which consists of droplets of much smaller size, represents one of the major hazards in transportation. Obviously, the optical properties of the same matter have greatly altered with diminution. In another example, it is well known that finely dispersed carbon is an excellent adsorbent, a property used in gas masks and in many industries as a purifying agent. Large-sized lumps of such carbon would be useless in these applications.The effect of particle size on properties of materials can be readily understood from a simple consideration. The total energy of any System, (Etot), consists of two contributions, the internai energy, Ei, and the surface energy, Ei.
Refractories: Something Old and Something New
Authors: Moore Robert E. 
Published: August 2016

The earliest refractories for containing melts were quarried from natural deposits of limestone and dolomite. Today these two carbonate rocks serve important roles in the production of metal contact refractories. Early refractories for glass melting on the other hand were manufactured from clays and claystones. These materials are also still used extensively for the batch melting of glasses that are hand formed or blown into art and tableware. Glass contact refractories for the continuous (tank) melting of glass are often fired, cast into large shapes, and arranged in a soldier course which constitutes the sidewalls of the glass tank.In this brief exposition of refractories technology and allied research, the articles by B. Brezny, T.F. Vazza and T.A. Leitzel, and by T.S. Busby cover materials development, selection, and properties of the systems which have evolved for the efficient melting of steels and glasses. As such they relate to extremes of technological flux in the processes for the manufacture of steel and glass, respectively.The continuous melting of large volumes of commercial glasses has been carried out in tanks equipped with reverberators for at least 70 years. The basic design of the overall system and of many of the glass fabrication machines for pressing, rolling, and blowing the glass has been constant since World War I. Only the introduction of the float glass method, the famous Pilkington process, for the production of flat glass, has interrupted the slow quiet progress in the technology of continuous glass making.