bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of Mesoporous Aerogels
Authors: Schaefer Dale W. 
Published: August 2016

Several emerging technologies depend on the development of porous materials with pore dimensions in the nanometer range (1 nm = 10 Å). Based on the canonical classification scheme, such materials are defined as “mesoporous materials.” Specialty uses, such as separation applications, require porosities engineered to meet stringent pore-size requirements, particularly for separating high-boiling-temperature or-ganics. In addition, commodity products, such as high-performance thermal insulation, await credible manufacturing methods to produce fine-scale pores. Finally, information discovered during the development of mesoporous materials could be helpful in finding new strategies to generate void-free ceramic materials by reverse engineering.Although several methods exist to generate nanometer porosity, our ability to tailor porosity for specific applications is still primitive. Because we lack adequate structural data and models for pore formation, the relationship between synthetic protocol and pore structure remains enigmatic.
Photorefractive Materials
Authors: Agulló-López F. 
Published: August 2016

There is a growing demand for nonlinear optical materials for a variety of applications—lasers and coherent sources, electrooptic devices, communication technologies, and optical processors and computers. Nonlinear optics is a vast field requiring materials with diverse performance features. Photorefractive (PR) materials, which experience a change in the refractive index under the effect of inhomogeneous illumination, constitute a relevant branch of the field. They behave as third-order nonlinear materials, which can be considered, in general, as photorefractive. However, the materials more commonly designated as photorefractives involve a charge-transport-induced nonlinearity, and it is these materials which are the object of this issue of the MRS Bulletin.At variance with conventional (often designated as Kerr) nonlinear materials, photorefractives are sensitive not to the local light intensity but to its spatial variation; i.e., they are nonlocal materials. This feature makes them more complicated to deal with than their conventional counterparts, since a χ(3) susceptibility cannot be properly defined (except as a k-dependent function). On the other hand, this sensitivity gives them some unique and interesting features. In particular, an interference light pattern illuminating the crystal and the generated index grating are phase-shifted, leading to remarkable beam coupling and amplification effects. The coupling gain can be markedly enhanced by applying alternating electric fields or by oscillating the interference fringes with a piezoelectric mirror. Efficient image amplifiers have been made using this effect.
Pulsed Laser Deposition: Future Directions
Authors: Venkatesan T. , Wu X.D. , Muenchausen R. , Pique A. 
Published: August 2016

Despite the discovery of the laser a few decades ago, the potential for pulsed laser deposition (PLD) of thin films has remained unexploited. Despite the sustained pioneering work at Rockwell in laser deposition, it took the development of high-temperature superconductors to fully realize the technique's potential. Early work on PLD of high-temperature superconductors demonstrated for the first time that the composition of rather complex multi-elementary materials can be reproduced in the deposited film under appropriate conditions of laser energy density and deposition angle. These features made PLD unique; and once the recipe for making in-situ crystalline films of proper stoichiometry was known, the technique's popularity was significantly enhanced in the research community.The features of laser deposition that make the process so unique, and that are discussed throughout this issue, are recapped below:1. Rather complex multi-elementary materials can be deposited well if a single-phase, homogeneous target can be fabricated. The complexity of the deposition process is translated to the relatively easier process of fabricating a high-quality target.2. The chamber pressure, target-substrate distance, target orientation with respect to the laser beam, etc. are significantly de-coupled, enabling significant freedom in deposition system design. The target is decoupled from the substrate in the sense that a small target can be used to deposit film over a fairly large area substrate with the appropriate scanning schemes.3. The efficiency of the target use is superior compared to any other technique since a predominant amount of the evaporated material is forward directed and can be collected with a high degree of efficiency. For example, in a production environment, more than 100 YBCO films (ranging 3,000-4,000 Å thick) on 1 × 1 cm2 substrates have been fabricated from a 0.25-inch-thick one-inch target with a majority of the target still left over. The cost of raw materials in a production environment may become significant, and for toxic elements particularly there is a further advantage in minimizing the spread of contaminants.
Up Close: Centra Nacional de Microelectrónica
Authors: Lora-Tamayo E. , Alvarez M.D. 
Published: August 2016

The Spanish National Microelectronics Center (Centra Nacional de Microelectrónica or CNM), a nonprofit R&D institute, was established in 1985 through the joint efforts of the General Directorate of Science (Ministry of Education) and the General Directorate of Electronics and Computer Science (Ministry of Industry and Energy).As a scientific research center, the CNM belongs to the Spanish Science Research Council (Consejo Superior de Investigaciones Cientifícas, CSIC), but differs from other CSIC centers in two ways. CNM is a direct spinoff of a nationwide scientific and technological research program (Programa Nacional de Microelectrónica), and it has its own board of trustees with representatives from different ministries (Education, Industry and Energy, Defense, and Communications); from the local governments of Catalonia, Andalusia, and Madrid; and from microelectronics-related industries.CNM's activities are channeled toward promoting microelectronics in Spain through scientific and technological research on the design and fabrication of integrated circuits, electronic devices, and related materials, while providing technological support for industry and university research groups. The global objectives are as follows:∎ Establishment of stable quasi-industrial technologies in technological niches that permit good interaction between CNM and industry. Among those niches, fixed by Spain's national industrial policy, are application-specific integrated circuits (ASICs), power devices, semiconductor sensors, and molecular beam epitaxy (MBE) technologies and associated devices.∎ Startup of precise technological processes or new IC design techniques through cooperative research projects with industry and/or university groups that involve carrying out research and technology development tasks, renewing established technologies, and the continuing training of researchers.
Teamwork and Statistical Quality Control at Owens-Corning Fiberglas Corporation
Authors: Choudhary Manoj K. 
Published: August 2016

The terms “teamwork” and “statistical quality control” (SQC) have become an established part of U.S. manufacturing vocabulary, though not necessarily of manufacturing practice. Much has been written on these subjects, as even a cursory glance at the literature reveals (e.g., see References 1–11). This article will describe the organization and functioning of an SQC team at Owens-Corning Fiberglas Corporation. My observations are not necessarily novel, but I hope they provide some useful insights into team building, teamwork, and SQC in a U.S. manufacturing environment.SQC is not a new concept at all, but it was largely ignored in the United States. The contribution of SQC (more accurately, Deming's and Juran's SQC precepts) to Japanese manufacturing quality has by now become a matter of folklore. This does not mean, however, that the SQC “philosophy” is correctly understood by U.S. companies. SQC is often viewed too narrowly as a production tool, or S and C in SQC are given undue attention. SQC is much more than a collection of statistical techniques. Indeed, the major impact of SQC results not from its engineering or technical attributes but from the changes it brings about in attitudes and in a factory's social organization. Drucker has identified SQC as one of the four concepts in the emerging theory of manufacturing.
Quality Architecture: A Concept for Quality Manufacturing
Authors: Bird L. , Frederick S. 
Published: August 2016

An engineer or a research scientist developing a new process is not often encouraged to build quality systems into the product or manufacturing process. However, today's market places greater emphasis and focus on stability and reliability of manufactured products. Corning has developed “quality architecture” to help engineers and scientists define and build the system elements that allow quality to be built into a product, rather than rely on inspection. A researcher or engineer can then provide a first-generation prototype of the quality systems, in addition to the first-generation prototypes of equipment and processes.What is Quality Architecture?Quality architecture involves designing a system that controls the manufacturing process in a stable and consistent manner, and provides for continuous improvement. The architecture defines and ensures the appropriate interdependence between product specifications, materials used in and by the process, product and process measurements, statistical process control and information systems. This results in a consistent and reliable product—features valued in today's market.
Earth Materials
Authors: Ewing Rodney C. , Navrotsky Alexandra 
Published: August 2016

This issue of the MRS Bulletin is devoted to Earth materials — a subject so broad and with such a long history, stretching back to man's first use of materials, that we can offer only a small sample of topics, only a partial review. As our ancestors fashioned the first crude tools from stone, they must have distinguished among materials on the basis of their physical properties. They classified materials by color and density and very early must have wanted more than Nature had provided. They began to synthesize and fashion their own materials. Today's nanoscale engineering of materials is part of this same quest—a continuous evolution of this early toolmaking.Thus, Earth materials were the first raw materials—and the first subjects of study and classification in materials science. Probably one of the earliest materials scientists to make quantitative observations was Nicolas Steno (1638–1686, actually Nils Stensen, a Dane by birth), who was among the first to note the “law of constancy of angle” in comments which accompany his drawings of quartz and hematite crystals (De Solido intra Solidum Naturaliter Conteno Dissertationis Prodromus, 1669). Such observations were the first clues to understanding the internal structure of solids. Steno was also a keen geological observer. He is given credit for the first statement of the law of superposition of sedimentary strata. The first quantitative experiments on the origin of minerals grew out of studies of glass and ceramics. French mathematician René-Antoine Ferchault de Réaumur (1683–1757) tried to determine the composition of Chinese porcelain by melting minerals and rocks.
Fundamental Concepts of Ion-Solid Interactions: Single Ions, 10−12 Seconds
Authors: Davies J.A. 
Published: August 2016

An energetic ion undergoes two major mechanisms of energy loss: (1) screened Coulomb collisions with target atoms (nuclear stopping), and (2) interactions with bound or free electrons in the solid (electronic stopping). This article discusses how these two energy-loss processes—and related quantities such as the ion range, collision cascade behavior, sputtering, and spike effects—depend on the experimental parameters of beam energy, atomic number, and target density. We restrict ourselves to an individual incident ion and a time scale (~10−12 s) sufficient for the cascade to fully develop (Figure 1), but short enough for subsequent quenching or diffusion processes to be ignored. What happens at longer times and higher ion f luences, due to diffusion and cascade overlap phenomena, is treated in the article by Brown and Ourmazd in this issue of the MRS Bulletin.Energy-Loss ConceptsFigure 2 summarizes the velocity (ε1/2) dependence of the two energy-loss processes, nuclear stopping (dε/dρ)n and electronic stopping (dε/dρ)e, in terms of the dimensionless Thomas-Fermi (TF) energy, ε, and length, ρ, units derived by Lindhard. The energy unit ε is defined as the ratio a/b where a is the TF screening length (typically, ~0.01 nm) and b is the distance of closest approach in an unscreened head on collision. The following simple relationship exists between TF and lab energies.where M1, Z1, M2, and Z2 are the masses and atomic numbers of projectile and target atoms.
Mechanisms of Stress-Induced and Electromigration-Induced Damage in Passivated Narrow Metallizations on Rigid Substrates
Authors: Korhonen M.A. , Børgesen P. , Li Che-Yu 
Published: August 2016

Narrow, passivated metal lines are generally used as interconnects in VLSI microcircuits at the chip level. In most metals, high electric current densities lead to a mass flow of constituent atoms accompanying the current of electrons. Electromigration (EM) has long been considered an important reliability concern in the semiconductor industry because the current-induced atomic fluxes can give rise to void formation and open circuits, or hillock formation and short circuits between nearby interconnects. The problem is exacerbated because of the continued trend of increasing the density of the devices on the chip. This means that the line widths of the interconnects have been reduced and are now in the submicron range; correspondingly, the current densities have increased and may be as high as 106 A/cm2. Recently, thermal-stress-induced damage in metallizations has also been recognized as an important reliability concern, perhaps of the same gravity as EM. Thermal stresses in the metallizations are caused by the different thermal expansion coefficients of the metal and the substrate. Stress-induced void and hillock formation are the main causes of in terconnect failures before service. More recently, concern has been growing that thermal stresses or thermal-stress-induced voids may enhance the subsequent electromigration damage during the service life of the microchips.For simplicity, this article addresses the case of pure aluminum metallizations on oxidized silicon substrates. However, much of what is said applies to other metal-rigid substrate systems as well, most notably to various aluminum and copper-based metallizations on ceramic substrates. The present treatment emphasizes void formation and growth in the metallizations during nd after cooldown from elevated temperatures, or those due to electromigration in service or testing conditions. Many of the mechanisms we explain are also applicable to hillock formation under compressive stresses, whether due to EM or thermal cycles during manufacturing.
Important Considerations for Processing Bi-Based High-Temperature Superconducting Tapes and Films for Bulk Applications
Authors: Hellstrom Eric E. 
Published: August 2016

High-temperature superconductors are brittle oxide ceramics, yet they have been made into wire that has been wrapped into solenoids and used in demonstration magnets and motors. Fabricating wires from these ceramics is an extremely challenging materials science process that requires a precisely engineered microstructure with the correct chemical, mechanical, and electromagnetic properties if these wires are to transport large current densities (Jc) in high magnetic fields. Heine et al. first demonstrated that wires of these materials could carry high Jc in very high magnetic fields. At 4.2 K, the oxide superconducting wires can carry higher Jc at higher magnetic fields than conventional Nb-Ti or Nb3Sn wires (Figure 1), and as shown in the companion article in this issue by Kato et al. they can also have high Jc at 77 K.Of the three major families of high-temperature superconductors, YBa2Cu3O7-x, Bi-Sr-Ca-Cu-O (BSCCO), and Tl-Ba-Ca-Cu-O, the best wires to date have been made in the BSCCO system. At present, all YBa2Cu3O7-x wires are weak linked and have only small Jc in magnetic fields. In the Tl-based system, the superconducting properties are potentially very interesting, but the toxicity of Tl and the system's complex processing have limited conductor development. For the Bi-based system, the basic processing steps are becoming known, the grains are well connected, and the weak link problem can be controlled. This permits applications in the temperature range 4–77 K, depending on the field and current density requirements of the particular use.
Materials Science and Technology: A Model for Achieving National Education Goals
Authors: Hays Irene D. 
Published: August 2016

In April 1991, President Bush unveiled “America 2000,” a national strategy for improving the overall performance of students in America's school system. He and the nation's governors developed the strategy as a result of the historical Charlottesville Summit, held in Virginia in 1989.America 2000 focuses on six national education goals, three directly related to mathematics and science education. Goal 4, in particular, states that “by the year 2000, US. students will be first in the world in science and mathematics achievement.” By the Year 2000, the report of the Federal Coordinating Council for Science, Engineering, and Technology (FCCSET) Committee on Education and Human Resources (CEHR) details the federal government's strategic objectives for meeting this goal.The primary objectives outlined in the report focus on (1) improving student performance, (2) providing a strong precollege work force, (3) ensuring an adequate pipeline for the science and engineering work force, including increased participation of underrepresented groups, and (4) improving public science literacy. I'll discuss later how a revolutionary materials science and technology curriculum developed by Pacific Northwest Laboratory (PNL) and Northwest teachers has proved to be a model for meeting these objectives.The FCCSET/CEHR report identified precollege as the educational level receiving the highest priority. At this level, the strategy for achieving the objectives is structured around (1) improving teacher preparation and enhancement, (2) reforming curricula, (3) organizing systemic reform, and (4) providing student incentives and opportunities.
Problems in Engineering and Science Education: Why Do We Have a Weakness in Materials Synthesis and Processing?
Authors: Eagar Thomas W. 
Published: August 2016

A 1989 report by the National Research Council (NRC) entitled, Materials Science and Engineering in the 1990s: Maintaining Competitiveness in the Age of Materials, strongly emphasizes that the United States as a nation has devoted insufficient resources to materials synthesis and processing, yet it fails to suggest why. If we are to correct such an imbalance, it is essential that we understand the cause so we can effect a solution.In my opinion, the cause of our failure to place sufficient emphasis on synthesis and processing is more fundamental than the study of materials science and engineering alone; it is symptomatic of the way we teach all science and engineering. We have failed to instill balanced attitudes of inquiry within our students. They have emulated our academic approach to defining and solving problems, an approach that works very well in academia but unfortunately is not always effective in the world of business and manufacturing. As a result, to be successful in the commercial sector, the young engineer or scientist must “unlearn” much of what has been taught in the universities.
Art-and-Technology: Recent Efforts in Materials and Media
Authors: Piene Otto 
Published: August 2016

To avoid misinterpretation, the term “art-and-technology” should be hyphenated because we are looking at an integrated art form which developed, roughly, during the past 70 years (since Naum Gabo's virtual volume, Kinetic Construction, Berlin, 1920). Art-and-technology results from “incorporated” contributions of art, science, and technology or, better, from artists, scientists, and engineers (plus industry, business, government, etc.). Although art-and-technology has frequently been bad-mouthed or even pronouned “dead” by advocates and practitioners of pure art as well as science and technology, it is alive and well and enjoying more vitality, variety, and expansion than ever before. It is currently the only expanding field in the arts; it feeds vitally into technology and industry—most visibly in entertainment but it also provides stimulus beyond fun to areas of science and engineering where “art applications” have abounded since the advent of photography and its vast consequent uses in science.We can claim an eloquent tradition for art-and-technology in ancient historic, cultural manifestations such as the Egyptian pyramids and their “environmental” scale or the Greek theater with its elaborate stage machines. We are aware of elements of that tradition when we observe contemporary art-and-technology such as sky and space art (Figures 1 and 2), computer-generated virtual reality, performance with medical inquiry and medical apparatus, and art concepts inspired by molecular biology (Figure 3). Emphasis of search—whether artistic/expressive, conceptual/philosophical, or inquisitive/scientific—depends on taste and motivation. However, Leonardo is an undisputed idol to both artists and scientists.
Coulomb's Data on Harpsichord Wire
Authors: Goodway Martha , Savage William R. 
Published: August 2016

Charles-Augustin Coulomb published data on the size, strength, and stiffness of harpsichord wire available in Paris in the late 18th century which has not been cited in the literature on musical instruments despite this century's revival of baroque music and the instruments upon which it was played. During an investigation of the internal friction of several antique music wires by means of a torsion pendulum similar to the one invented by Coulomb and first described in the 1784 mémoire (Figure 1), it occurred to us to ask what Coulomb had used as the suspensions in his pendulum. His biographer, C.S. Gillmor, mentioned “harpsichord strings”, and in Coulomb's 1784 Torsion mémoire we found: J'ai pris trois fils de clavcin, tels qu'on les trouve répandus dans le commerce, roulés sur des bobines, et numerotés (“I used three harpsicord wires, such as one finds distributed in commerce, wound up on spools, and numbered”).The spools of wire recently discovered in the stand drawer of a harpsichord in France fit Coulomb's description. The instrument was built in Paris in 1732 by Antoine Vater, and the wire found with it was wound up on small wooden spools similar to spools for thread. The spool of red brass wire had a mark punched in one end and the spool of iron wire had the gauge size (No 5) written on it in ink, while the spool of yellow brass wire had neither mark nor number. Samples of the wires from these three spools, generally agreed to be of 18th century manufacture, were collected by J. Scott Odell of the Smithsonian Institution as part of a research project which he initiated into the physical properties of antique wire. With these samples in hand it was possible to measure certain of their properties and to compare these properties with those reported in Coulomb's Torsion mémoire in 1784. Since Coulomb's wire was undoubtedly of 18th century manufacture (a degree of confidence that we do not always have with collected samples), and the data were taken not long after the wire was drawn, comparison with the Vater wire allows us to detect if, during two centuries, significant changes occur in highly drawn wire.