bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Approaches for Assessing the Preservation of Historic Silks: A Case Study of the First Ladies' Gowns
Authors: Becker Mary , Tuross Noreen 
Published: August 2016

Friable natural products are often used in articles of personal adornment, and the perishable nature of these materials presents a unique challenge to museums. At the Smithsonian's National Museum of American History, a collection of gowns worn by the First Ladies of the United States is a popular display of historical and sentimental import. Opened to the public on February 1, 1914, fifteen gowns were displayed as part of a “Period Costumes“ exhibit in the U.S. National Museum (now known as the Arts and Industries Building). Within just a few years, the exhibit was recognized as “one of the most interesting and popular in the Museum.” A First Ladies' Hall was created in the mid-1950s to exhibit the gown collection in period room settings. This design theme continued when the Hall moved to the Museum of American History and Technology (now the National Museum of American History) in 1964. The First Ladies' Hall was closed for renovation in 1987, allowing the curatorial staff to reassess the collection's use and conservators to perform long overdue examinations and treatments. Reinstallation of the exhibit is scheduled for spring 1992.The First Ladies' conservation project includes a history of each gown's use and exhibition as related to its physical condition and also includes stabilization treatments to meet the demands of future display. The current conservation project provided an unusual opportunity for extensive research into fabric deterioration of a popular and important collection. The goals of the research are twofold: first, to determine each object's state of preservation by studying the effectivenss of several analytical approaches with minimal destructive sampling and, second, to begin investigating the mechanisms involved in the degradation of silk, the material predominant in this collection.
Molecular Beam Epitaxy From Research to Manufacturing
Authors: Cho A.Y. 
Published: August 2016

Tonight I will talk about molecular beam epitaxy (MBE) from research to manufacturing. First I will discuss the introduction of MBE in the early 1970s and the exciting achievements made with it. I will conclude with some new directions for MBE.First let us review this technology. Through MBE, materials like semiconducting materials, metals, and insulating materials are grown, atom layer by atom layer. Figure 1 shows a stainless steel MBE chamber, pumped to a pressure of approximately 10−10 torr, with liquid-nitrogen-cooled shrouds to further condense the water vapor in the vacuum system. To grow gallium arsenide (GaAs), we mount a substrate in the center where it continuously rotates to give us the uniformity we need, and it is heated to about 580° or 600°C. The effusion cells are filled with pure Ga, pure As, and doping elements such as silicon for n-type doping, and then germanium or beryllium for p-type doping. Important in this MBE system are the in situ monitoring techniques. The system contains a reflection high energy electron diffraction (RHEED) apparatus, producing an electron beam with a grazing angle to the substrate of about one degree. The diffracted electrons are projected on a fluorescent screen. Through the diffraction pattern, we can look at the surface as it is cleaned by desorption of the oxide before we deposit and grow semiconducting materials.
Modeling Diffusion in Gallium Arsenide: Recent Work
Authors: Haddara Yaser M. , Lee Cynthia C. , Hu Jerry C. , Deal Michael D. , Bravman John C. 
Published: August 2016

Second to silicon (Si), the most highly developed technology for semiconductor processing exists for gallium arsenide (GaAs). Unfortunately, GaAs processing is more complex than that of Si, mainly because GaAs is a compound semiconductor. Additionally, the lack of a stable native GaAS oxide and other disadvantages relative to Si have prevented this material from expanding beyond the small niche of applications where its high intrinsic electron mobility, superior radiation hardness, and direct bandgap are essential. Adequate understanding and modeling of the process physics are important for extending the “process window” available to GaAs manufacturers and for increasing the appeal of this material. This article deals with one of the most important process events: dopant diffusion.In the next section we briefly describe device-fabrication technology and show the importance of diffusion modeling in the prediction of device characteristics. We then review some elementary diffusion mechanisms and outline the dopants that are important in GaAs-processing technology as well as the methods by which these dopants are introduced into the substrate. In subsequent sections we review the research community's current understanding of diffusion mechanisms as well as model parameters for specific dopants. Much work has been done in this field, at Stanford and by other groups, since the publication of a major review of the subject by Tan et al. in 1991. In this article, we focus on these recent contributions.
Semiconductor Nanocrystals
Authors: Alivisatos A. Paul 
Published: August 2016

The following is an edited transcript of the presentation given by A. Paul Alivisatos, recipient of the Outstanding Young Investigator Award, at the 1995 MRS Spring Meeting in San Francisco.The work I will describe on semiconductor nanocrystals started with the realization that it is possible to precipitate a semiconductor out of an organic liquid. We can precipitate out a semiconductor as a colloid—a very small-sized semiconductor with reduced dimensionality—that will show large, quantum size effects. A dream at that time was to make an electronic material by such a process in a liquid beaker, by starting with an organic fluid and somehow injecting something into the fluid to make very small particles, which we could use in electronics. The materials we use in electronics today have perfect crystalline order. We are able to put in dopants very specifically, or control precisely their arrangements in space in enormously complicated ways. The level of purity of electronic materials is so high that making an electronic material in a wet chemistry approach seems almost impossible. If, in addition, we specify that the size must be controlled precisely, we recognize the project is a problem for basic research, yet not one ready for applications. Many fundamental problems arise if we try to make semiconductor particles, in a liquid, of such high quality that they can be used as electronic materials.
Electronic Access to Factual Materials Information: The State of the Art
Authors: Westbrook J.H. , Kaufman J.G. , Cverna F. 
Published: August 2016

Over the past 30 years we have seen a strong but uncoordinated effort to both increase the availability of numeric materials-property data in electronic media and to make the resultant mass of data more readily accessible and searchable for the end-user engineer. The end user is best able to formulate the question and to judge the utility of the answer for numeric property data inquiries, in contrast to textual or bibliographic data for which information specialists can expeditiously carry out searches.Despite the best efforts of several major programs, there remains a shortfall with respect to comprehensiveness and a gap between the goal of easy access to all the world's numeric databases and what can presently be achieved. The task has proven thornier and therefore much more costly than anyone envisioned, and computer access to data for materials scientists and engineers is still inadequate compared, for example, to the situation for molecular biologists or astronomers. However, progress has been made. More than 100 materials databases are listed and categorized by Wawrousek et al. that address several types of applications including: fundamental research, materials selection, component design, process control, materials identification and equivalency, expert systems, and education. Standardization is improving and access has been made more easy.In the discussion that follows, we will examine several characteristics of available information and delivery systems to assess their impact on the successes and limitations of the available products. The discussion will include the types and uses of the data, issues around data reliability and quality, the various formats in which data need to be accessed, and the various media available for delivery. Then we will focus on the state of the art by giving examples of the three major media through which broad electronic access to numeric properties has emerged: on-line systems, workstations, and disks, both floppy and CD-ROM. We will also cite some resources of where to look for numeric property data.
New Rapid Failure Analysis Techniques for Multilevel Metallization
Authors: Cole Edward I. , Anderson Richard E. 
Published: August 2016

Open interconnections on integrated circuits (ICs) are a serious and ubiquitous problem throughout the micro-electronics industry. The efforts to understand the mechanisms responsible for producing open interconnections and to develop analytical methods to localize them demonstrate the concern manufacturers have for this problem. Multiple layers of metallization not only increase the probability that an open conductor or via will occur because of the increased number of interconnections and vias but also increase the difficulty in localizing the site of the failure because upper layers may mask the failure site.Rapid failure analysis of open-conductor defects is critical in new product development and reliability assessment of ICs where manufacturing and product development delays can cost millions of dollars a day. In this article, we briefly review some standard failure analysis approaches and then concentrate on new techniques to rapidly locate open-conductor defects that would have been difficult or impossible to identify using earlier methods. Each method is described in terms of the physics of signal generation, application, and advantages and disadvantages when compared to existing methods.
The Reliability of Aluminum/Tungsten Technology for VLSI Applications
Authors: Shacham-Diamand Yosi 
Published: August 2016

Interconnects technology and back-end processing moved to the center stage of very large-scale integration (VLSI) technology in the mid-1980s. At that time, the critical dimensions dropped below 1 μm while the chip size and complexity increased to a level where interconnects were recognized to be a limiting factor. As dimensions decreased, the step coverage of sputtered aluminum inside contacts and via-contact holes decreased and alternative technologies were studied. The increasing cost of ownership (COO) of single-wafer Al sputtering processes also supported the search for alternative technologies, such as tungsten chemical vapor deposition (CVD) for via contacts and plugs (Figure 1). Only recently have all the W CVD process steps been optimized to lower cost without loss of reliability and/or performance. The development of cluster tool technology and multiwafer process modules also allowed reliable and cost-effective utilization of the W/Al technology.Tungsten technology for VLSI circuits became complementary to that of aluminum. Tungsten thin-film resistivity ρw = 7–8 μΩ cm is much higher than that of aluminum ρAl = 3–4 μΩ cm, introducing large W interconnect resistance-capacitance (RC) delays compared to Al. Therefore, tungsten is not favorable for high-speed global-interconnect schemes. However, tungsten is suitable for local interconnects where the impedance of the driving transistors is dominant and the RC interconnect delay is less significant. Tungsten is also suitable for contact filling, in which the via resistance is negligible. For these applications, tungsten became a dominant technology and was integrated with the aluminumalloy-based technology used for global interconnects.
Sputter Synthesis of Ferroelectric Films and Heterostructures
Authors: Auciello O. , Kingon A.I. , Krupanidhi S.B. 
Published: August 2016

Ferroelectric films can display a wide range of dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties. The potential utilization of these properties in a new generation of devices has driven the intensive studies on the synthesis, characterization, and determination of processing-microstructure-property relationships of ferroelectric thin films during the last five years. In addition there has been an increased drive for integrating ferroelectric film-based heterostructures with different substrate materials to demonstrate numerous devices that exploit the dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties of these materials. For example the high dielectric permittivities of perovskite-type materials can be advantageously used in dynamic random-access memories (DRAMs), while the large values of switchable remanent polarization of ferroelectric materials are suitable for nonvolatile ferroelectric random-access memories (NVFRAMs).Various vapor-phase deposition techniques such as plasma and ion-beam sputter deposition (PSD and IBSD, respectively), pulsed laser-ablation deposition (PLAD), electron-beam or oven-induced evaporation for molecular-beam epitaxy (MBE), and chemical vapor deposition (CVD) have been applied to produce ferroelectric films and layered heterostructures. See References 4–7 for recent reviews. However, work is still necessary to optimize the techniques to produce device-quality films on large semiconductor substrates in a way that is fully compatible with existing semiconductor process technology. Therefore research efforts should be focused on the optimization of suitable process methods and on the investigation of processing-composition-microstructure property relationships. These efforts are the focus of this article with emphasis on PSD and IBSD techniques.
Embedded-Atom and Related Methods for Modeling Metallic Systems
Authors: Foiles Stephen M. 
Published: August 2016

This article discusses simple but realistic models of the bonding in metallic systems. As is discussed in the introduction, such methods are valuable both to study complex systems that are intractable with more rigorous methods and to study generic properties that do not depend on the fine details of the energetics. In addition, simple models are useful for gaining a physical understanding of a system.As discussed in the article by Vitek, a great deal of progress in the understanding of defect structures has been gained by the use of constant-volume pair potentials, that is, pair-potential models that include a volume-dependent term. In this picture, the energy is assumed to have two parts, a large density-dependent but structure-independent part and a structure-dependent part that is represented by pair interactions. This view follows from a physical picture where the metal is viewed as a uniform electron gas and the interactions between the atoms are obtained by performing perturbation theory on this reference system. This approach has a serious limitation, though, in that it is restricted to situations where the system is essentially uniform such as when the bulk or defects do not introduce significant changes in the local density. This is true for two reasons. First, there is not a clear prescription for how the structure-independent part of the energy should be treated in an inhomogeneous region. This is a serious problem since a large part of the binding energy is included in this term. Second, the pair-potential term in this picture depends on the overall density. In the vicinity of a inhomogeneity such as a surface, there is no prescription for how the pair-potential term should vary.
Biosynthesis and Processing of Silk Proteins
Authors: Kaplan David L. , Fossey Stephen , Mello Charlene M. , Arcidiacono Steven , Senecal Kris , Muller Wayne , Stockwell Scott , Beckwitt Richard , Viney Christopher , Kerkam Keven 
Published: August 2016

Silks produced by silkworms (e.g.,Bombyx mori) and orb-web weaving spiders (e.g.,Nephila clavipes) are essentially pure protein, that is, complexes of amino acid polymers. They are the most common fibers spun by biological systems. There has been a long-standing interest in the use of these and similar fibers in textiles, cables, fiber reinforcement in composites, in addition, for example, to cross hairs in optical instruments, and fishing nets. Both nylon, a homo-polymer of the amino acid glycine, and Kevlar, a polymer of a nonnatural aromatic amino acid, can be considered modified, synthetic versions of silk and are used for some of the applications mentioned above. The potential for genetic manipulation, through recombinant DNA technology, of the natural biosynthetic process for these natural proteins (see the article by Cappello in this issue) has renewed interest in the production of new silklike proteins.The natural silks are characterized by aβ-sheet secondary structure which is stabilized by interchain hydrogen bonds and intersheet hydrophobic interactions (Figure 1). Silks can be considered block copolymers, with crystalline domains consisting of short side chain monomers (the amino acids glycine, alanine, and serine) interspersed in amorphous domains consisting of bulkier side chain amino acids.This family of fibers is naturally tailored to perform functions such as catching prey (orb web) or serving as a barrier against environmental challenges (cocoon). The domestic silkworm (B. mori) produces only one type of silk, cocoon silk, at only one stage in its lifecyle, during the fifth larval instar just before molt to the pupa. The silk is produced in modified salivary glands and spun from the mouth.
Microbial Synthesis and Properties of Polyhydroxy-alkanoates
Authors: Doi Yoshiharu 
Published: August 2016

A wide variety of microorganisms accumulate an optically active polymer of D(−)-3-hydroxybutyric acid, P(3HB), as an intracellular storage material of carbon and energy. The P(3HB) was first isolated fromBacillus megateriumin 1925 by Lemoigne. Many prokaryotic organisms, such as bacteria and cyanobacteria, have been found to accumulate P(3HB) up to 80% of their cellular dry weight when growth is limited by the depletion of an essential nutrient such as nitrogen, oxygen, phosphorus, or magnesium. Recently, many bacteria have been found to accumulate copolymers of D(−)3-hydroxy-alkanoic acids with a chain length ranging from three to 14 carbon atoms. In addition, 4-hydroxybutyric acid was found as a constituent of bacterial polyhy-droxyalkanoates (PHA).Bacterial PHA polymers have attracted much attention as environmentally degradable thermoplastics for a wide range of agricultural, marine, and medical applications. PHA is degraded in soil, sludge, or sea water. Some microorganisms such as bacteria and fungi secrete extracellular PHA depolymerases to degrade environmental PHA and utilize the decomposed compounds as nutrients. In this article, I report the metabolism, production, and properties of bacterial PHA.
Structure-Properties Relations in Cheese
Authors: Sharkasi Tawfik , Kilara Arun 
Published: August 2016

Cheese is a popular food among people of all ages and its popularity stems from its nutritional value and convenience. Cheese comes in many varieties, shapes, and sizes. It makes an ideal snack food. The recent expansion of ethnic foods that include cheese as an ingredient is somewhat responsible for the increased use of cheese. Per capita consumption of cheese has roughly doubled over the past 20 years. The annual U.S. per capita consumption increased from 12.4 to 24.7 lbs. Rapidly expanding restaurant pizza sales and changes in lifestyles that emphasize convenience food are also major factors affecting cheese trends. The increasing popularity of pizza has caused consumption of mozzarella cheese to more than double in the past decade alone. Cheese sales in 1993 reached about $17.2 billion. Concerns over fat intake and its affect on health has resulted in a growing production of the “light” varieties, which represent about 38% of all new cheese products introduced in the past two years.The origin of cheese as a staple in the human diet is lost in history. By some accounts, cheese has been around for 6,000 to 7,000 years. It was standard fare for the Egyptians of about 2000 B.C. and many types were made by the Romans. Cheese making skills were brought by settlers who migrated due to famine, conflicts, and invasions. The Roman invasion of Britain brought a new art of cheesemaking to that country, although cheese may have been made there previously.
Copper Metallization Technology for Deep Submicron ULSIs
Authors: Arita Y. , Awaya N. , Ohno K. , Sato M. 
Published: August 2016

Investment in high-performance and large-scale integration (LSI) has been increasing and low-cost fabrication equipment, simple processing, and short turnaround are big concerns. The propagation delay time in a device is reduced with a reduction in device size, and wiring delay becomes longer than device delays. Wiring then has become as important as the device itself. Future multilevel wiring will require five to seven levels. The multilayer wiring itself will not be easy to achieve, because of increased wiring cost, process complexity, and longer turnaround. We must overcome these problems.The materials required for wiring so that ULSI performance and reliability in RISC (reduced instruction set computer), and CISC (complex instruction set computer) type processors and DSPs (digital signal processors) can be increased must have a lower resistivity and higher resistance to electromigration (EM) and stress migration (SM) than do aluminum alloys. Gold, copper, and silver are candidate wiring materials. Copper is especially attractive, but we must overcome several obstacles to take advantage of its potential.This article will discuss wring and via resistance delay, Cu CVD technology, the surface reaction mechanism, copper patterning technology, copper oxidation and diffusion prevention, and copper wiring reliability.