bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brief Communication: The Effect of Toxic Microbes on Accelerator Performance
Authors: Smart I.M. , Tu U.R. , Sport B.A. 
Published: August 2016

AbstractThe potential of the environment inside evacuated accelerator beam-lines for breeding microbes which are both toxic to users and possess electric or magnetic organs of strength sufficient to deflect soft charged-particle beams has been explored. Unexplained human and accelerator “long-runtime” syndromes plaguing accelerator facilities for many years can be understood from this study. We have artificially bred such organisms and demonstrated that they are the cause of these syndromes. An appropriate microbicide-impregnated antiseptic beampipe liner with good outgassing properties could alleviate the problem.
Science and Techniques Using Pulsed Magnetic Fields
Authors: Franse J.J.M. , Miura N. 
Published: August 2016

In this article, we examine materials behavior in the magnetic field region from about 40 T to 500 T using pulsed magnet technology. Examples of materials science using two different pulsed magnet technologies are described in this article.Semicontinuous MagnetsSince the late 1960s, the University of Amsterdam has operated a semicontinuous magnetic field installation that produces magnetic fields up to 40 T with typical time constants of about one second. The magnet coil is constructed from hard-drawn copper wire with a reinforcement cylinder of maraging steel positioned at roughly one third of the outer diameter. Before operation, the coil is cooled to 30 K by cold neon gas. The power for this installation is taken directly from a 10 kV connection to the public electricity grid. By means of a thyristor-based power control system, highly flexible field-time profiles can be realized: step-wise pulses can be generated with field levels constant within 10−4 during 100 ms; linearly increasing and decreasing fields as well as exponentially ripple-free decreasing fields are other examples of standard field-time profiles. Among the measuring techniques frequently used are magnetization, magneto-transport, quantum oscillations, relaxation phenomena, etc. Temperatures at which experiments can be performed range from 400 mK to room temperature. In the Netherlands, the Amsterdam High Field Facility has recently been combined with the High Magnetic Field Laboratory in Nijmegen, where static magnetic fields up to 30 T are produced in hybrid magnet systems, to form the Amsterdam-Nijmegen Magnet Laboratory (ANML). The high field research of ANML comprises semiconductors, magnetism in transition-metal compounds, heavy-fermion physics, superconductors, organic conductors, and magnetic separation. We present here a few selected topics.
CulnSe2 and Other Chalcopyrite-Based Solar Cells
Authors: Schock Hans-W. 
Published: August 2016

CuInSe2 and related chalcopyrite semiconductors are among the compound semiconductors that have been considered for thin solar cells for about the past 20 years. Recently, high efficiencies close to 17% have been achieved. This result could be the starting point for a new category of solar cells—high-performance thin-film cells—that would combine the high performance of single-crystal cells with possible low-cost thin-film processing.The development of CuInSe2 cells started in 1974, when single-crystal cells with an efficiency of 12% were reported by a group at Bell Laboratories. Soon after, thin-film solar cells were demonstrated by Kazmerski et al. CuInSe2 thin films have been deposited by evaporating the CuInSe2 source material to completion and adding Se from a separate source. It was found that straight-forward evaporation of the compound does not generally lead to films with stoichiometric composition. By coevaporation of the elements, films with any desired composition can be obtained, provided there is appropriate process control. A “bilayer” recipe developed by Boeing, namely combining Cu-rich films and In-rich films, solved the problem of combining larger grains with suitable electronic properties. By this method, the first CuInSe2 thin-film solar cells with an efficiency exceeding 10% conversion efficiency were fabricated.Alloying CuInSe2 with CuGaSe2 and CuInS2 considerably increases the potential for the innovative development of solar cells from these materials. The energy gaps covered by these alloys range from about 1 eV to about 2.4 eV The possibility of increasing the energy gap and achieving absorber layers with graded bandgaps has many advantages for the application of these materials in thin-film solar cell modules.
III-V Materials for Photovoltaic Applications
Authors: Fraas Lewis M. 
Published: August 2016

While there are only two group IV semiconductors, Si and Ge, the III-V material system offers a nearly infinite number of single-crystal semiconducting compounds to choose from. For example, there are nine binary compounds resulting from combining the group III elements Al, Ga, or In with the group V elements P, As, or Sb. From this group, high-performance photovoltaic cells have been made from GaAs, GaSb, and InP. Using ternary III-V compounds, high-performance photovoltaic devices have been made with AlGaAs, GalnAs, GaAsP, and InGaP2. All of the above-cited photovoltaic cells have respectable energy conversion efficiencies of over 15%.A primary strength associated with the III-V semiconductor material system lies therefore in the diversity of materials to choose from. Thus, a single-crystal III-V compound can be found with almost any bandgap ranging from 0.16 eV for InSb to 2.24 eV for GaP (or 3.5 eV for GaN). But not only can one choose a material with a particular bandgap, one can, more importantly, as a result of tetrahedral covalent bonding, also be assured that that material can be grown as a single crystal with either n- and p-type doping, and that junctions can be formed with nearly ideal rectifying characteristics. The implication this holds for solar cells of ideal diode characteristics is the achievement of theoretical limit open-circuit voltages and fill factors. An additional important feature associated with many of the III-V compounds is the direct-gap photon absorption which translates to a short optical absorption distance, with the result that excited-state carriers in a solar cell are created near the junction.
Iron Sulfide for Photovoltaics
Authors: Dasbach R. , Willeke G. , Blenk O. 
Published: August 2016

In recent years, iron sulfide (FeS2), otherwise known as pyrite, has received some attention as a possible candidate for thin-film photovoltaic applications. This interest stems in part from the fact that it has a relatively large absorption coefficient of α > 105 cm−1 for photon energies larger than about 1.3 eV (see Figure 1), such that a thin layer of less than 1,000 Å should effectively absorb the visible part of the solar spectrum. The bandgap of pyrite of 0.95 eV is probably on the borderline of what might still be considered acceptable for a high-efficiency single-junction device, but can be considered ideal in combination with a 1.8 eV material for tandem structures. Another important advantage of this compound semiconductor is that it is composed of cheap, abundant, and non-toxic elements, the latter being of particular importance in times of growing environmental consciousness.Pyrite is a naturally occurring mineral (also known as “fool's gold” because of its golden color) which shows both n- and p-type conduction. This could indicate possible electronic viability of this material. The study of synthetic crystals has been severely impeded by the fact that pyrite undergoes a peritectic decomposition into the more stable FeS and liquid sulfur at 743°C and that therefore the melt growth of high-purity large single-crystalline material is not possible. Nevertheless, it has been shown that polycrystalline pyrite layers could be prepared with different thin-film preparation techniques (see Table I), such that in principle a cost-effective large-scale application could be envisaged.
Test Structures as a Way to Evaluate Packaging Reliability
Authors: Palmer David W. 
Published: August 2016

Electronics packaging has always accounted for about 50% of reliability shortcomings in electronics systems. Materials, processes, and geometries used in microelectronics packaging are quickly evolving to meet the commercial challenge for more reliable, lighter, smaller, cheaper devices, and lower power consumption. Amid the rapid evolution, methodology and metrology to measure package reliability and materials aging properties must be standardized to allow quantitative technology comparisons.What Is Packaging?For most purposes packaging can be thought of as everything involved in making an electronics system except the wafer fabrication. For example, all the design, fabrication, assembly, and finishing that goes into interconnecting the integrated circuits, discrete devices, resistors, and capacitors and then interfacing the system to the user is traditionally called “packaging.”
Properties and Control of “Stickies” in Paper Recycling
Authors: Doshi Mahendra R. 
Published: August 2016

Large amounts of waste paper are generated every day and interest in its reuse has increased steadily due to environmental concerns and improved economics. In 1990 in the United States, for example, 28.9 million tons of recovered papers were collected for recycling. By 1995, that amount is expected to increase to almost 40 million tons with a collection rate of almost 40%. To facilitate the use of secondary fibers, sticky contaminants, or “stickies,” must be controlled.Classification and Properties of StickiesRecovered paper bales usually contain extraneous materials such as sand, glass, staples, nails, inks, coatings, plastic, styrofoam, wax, EVA (ethylene vinyl acetate), and SBR (styrene butadiene rubber). A particularly troublesome contaminant in recovered paper is “stickies” which, in their original state, were used as paper adhesives. Inks and coatings can also be a source of stickies. Inks are primarily composed of a pigment, liquid vehicle, binder, and modifier. Coating formulations contain several ingredients that can be classified as pigments, binders, and additives, such as plasticizers, thickeners, dispersants, dyes, preservatives, and defoamers. Note that both inks and coatings mixtures contain binders which contribute to the stickies problem. Common binders used in inks are hydrocarbon resins and rosin esters while those used in coating formulations include starch, soya protein, acrylics, and polyvinyl acetate. An overview of stickies was presented by Moreland.Stickies can be classified into three categories: hot melts, pressure-sensitive adhesives, and latexes. Although wax can be a contaminant, it is not included separately because it is similar to and an important ingredient of most hot melts.Contaminants such as plastics and styrofoam are also excluded from this discussion because they are not stickies.
Filler Pigments Designed for Recyclability
Authors: Passaretti June D. , Young Trudy D. , Herman Mick J. , Evans D. Bruce 
Published: August 2016

Printing and writing paper represents 30% by weight of all domestically made paper products. Today, however, less than 50% of that paper is recycled. The problem with waste paper from homes and offices is that it contains dyes, inks, and chemicals. If these additives are not removed properly—with no fiber degradation—the recycled paper will be of an inferior quality for writing and printing.Recycling, however, is the future. In 1990, 28.9 million tons of paper were collected for recycling, representing a collection rate of 33.5%. By the year 1995, the collection rate goal is 40%, with favorable economics supporting increased utilization of recovered paper. For example, a ton of paper made from 100% waste paper saves 17 trees, 4,100 kWh of energy (approximately 6 months of power used by the average home), 7,000 gallons of water, 60 pounds of air-polluting effluents, and 3 cubic yards of landfill.Two of the issues facing recycled fiber utilization are the cost and visual quality of the final sheet. Paper brightness, opacity, and printability are the industry's biggest concerns when comparing the quality of recycled fibers to that of virgin fibers. The common approach to increasing brightness is to add a white filler pigment such as precipitated calcium carbonate (PCC), ground limestone, clay, and/or titanium dioxide. Chemical optical brighteners have also been used, but their use will decline as consumers ask what impact the brightening chemicals have on the environment.
Up Close: Institute C. Sadron Takes a Comprehensive Approach to Polymer Blends
Authors: Weill Gilbert 
Published: August 2016

If one defines a polymeric material as a piece of matter designed for a given and usable property, this property is not related simply to the chemical formula of the polymer. The chemical and stereochemical defects occurring during synthesis, structural organization, and processing must all be characterized, understood, and controlled.Institute C. Sadron (ICS), established in 1954 by the French National Research organization (CNRS) as the Centre de Recherches sur les Macromolécules under the inspiration and direction of Prof. Ch. Sadron, has progressively shifted from polymer synthesis and characterization toward the understanding of the structure-property relationship in the sense just described. This has involved the creation of an engineering school staffed with equipment and research teams in rheology, processing, and mechanical properties. More than 60 permanent scientists and university professors work in the Institute; about 20 theses are submitted each year. ICS now covers a broad range of competencies, from synthesis to processing through most techniques of characterization and theoretical modeling at the molecular and macroscopic levels. This opens the way to a comprehensive research effort, which is illustrated here for polymer blends.
Alternatives to CFCs and Global Warming: A Systems Approach to Evaluating Net Contributions
Authors: Fischer Steven K. , McFarland Mack 
Published: August 2016

CFCs proved to be one of the more useful classes of compounds ever developed because of their many desirable properties. They promote worker and consumer safety because they are nonflammable, noncorrosive, and very low in toxicity. They are used in a wide variety of applications, such as refrigerants, foam blowing agents, and cleaning solvents, because of their desirable physical properties that enhance energy efficiency and product reliability.However, some of the properties that make CFCs desirable from a worker and consumer safety and applications standpoint have led to global environmental concerns. Because of their chemical stability, CFCs have long environmental residence times, and emissions lead to accumulation in the lower atmosphere. CFCs slowly mix into the upper atmosphere where they dissociate, releasing chlorine atoms that can catalyze destruction of ozone. Recent scientific findings have clearly linked chlorine from CFCs and other man-made compounds and bromine from man-made and natural sources to the seasonal ozone losses over Antarctica, the Antarctic ozone hole, and have indicated that these compounds are probably causing ozone losses over populated areas of both the northern and southern hemispheres as well. Since ozone provides a screen against solar ultraviolet radiation (UV-B) and excess UV-B has a potential to contribute to health and environmental concerns, significant reductions in ozone should be avoided. This information provides a sound basis for the Montreal Protocol, an international agreement amended in 1990 requiring a total phaseout of CFC production and consumption by 2000.
Status of Low-Dose Implantation for VLSI
Authors: Seidel T.E. , Larson L.A. 
Published: August 2016

This article describes the current status of implantation in silicon for ion doses up to but not including the onset of the amorphous state. Physical phenomena, applications to VLSI, and equipment issues are discussed and linked from the viewpoint of vertically integrated technologies (see Figure 1). In such a view, engineering applications are the customer of research on phenomena, and the equipment industry is the customer of both the research and applications community. The article highlights areas in phenomena, applications, and equipment requiring particular attention.Studies in physical phenomena associated with ion implantation are motivated by the need for very shallow junctions. The shallowness is limited by ion channeling effects in crystalline silicon (which directly affect the as-implanted impurity profile) and by diffusion (which occurs during implant activation and annealing of damage). The inventory of ion-damage induced defects includes point defects, cluster defects, and dislocations arising from the combination of damage and annealing. A recent survey by Schreutelkamp et al. of low-dose implantation describes advances in characterization of channeling effects, and the formation of dislocation damage which, in turn, impacts thermally processed profiles. These effects need to be understood in terms of modern MOS (metal-oxide-semiconductor) processes.
Subsurface Processing of Electronic Materials Assisted by Atomic Displacements
Authors: Williams J.S. 
Published: August 2016

In the early years of doping of semiconductors by ion implantation, atomic displacements and residual lattice damage were considered undesirable byproducts of an otherwise controllable doping process. Steps were taken to minimize disorder during implantation and/or to remove it as completely as possible during a subsequent annealing process. In many cases, such as boron- or phosphorus-implanted silicon, annealing temperatures exceeding 900°C were necessary to achieve the desirable electrical properties. Indeed, removal of implantation damage remains a crucial issue, particularly as device dimensions shrink and the need has arisen for substantially lower processing temperatures. The advent of high-energy (MeV) implantation in specific processing steps and the increasing use of more complex (often multilayer) compound semiconductors has added further to the need to understand and control ion damage and its annealing in semiconductors.Over the past decade, there has been a growing realization that implantation induced atomic displacements and defects can have significant advantages in processing. For example, it was realized early that ion damage, and resultant defect fluxes to and from lattice disruptions, can “getter” and trap undesirable impurities that would otherwise interfere with device operation. More recently, it has been possible to use ion beams to tailor damage structures and form amorphous-crystalline superlattices, to remove pre-existing damage and induce crystallization of amorphous layers at very low temperatures, to form ultrapure amorphous silicon for studying thermodynamic properties of this phase, or to mix films with semiconductors and form stable compounds such as silicides. Indeed, ion damage has been used to electrically isolate devices, to form optical waveguides and cavities, and to improve the junction properties of deeply doped layers. These issues are briefly reviewed in this article.
High-Temperature Superconductors from the Grain Boundary Perspective
Authors: Babcock Susan E. 
Published: August 2016

The high-transition-temperature superconductors (HTS) present a number of challenging materials science problems whose solutions must precede their use in applications. This article offers a view on our collective progress toward resolution of one central HTS issue, the “weak-link” character of high-angle grain boundaries.Why Are HTS Grain Boundaries of Such Interest?The properties of high-angle grain boundaries control the macroscopic electromagnetic character of all superconducting copper oxides that are produced in polycrystalline form. In particular, grain boundaries limit the transport critical current density (Jct) and determine its dependence on applied magnetic field (H) and temperature (T). Jct is the maximum macroscopic current density that the superconductor can support in the nondissipative state. H and T are the two most important environmental variables for applications of superconductivity. Thus, the Jct(H, T) characteristic largely dictates the types of applications for which a superconducting material can be used successfully.High-angle grain boundaries are the immediate obstacle to further development of materials for applications that require large Jct values in high magnetic fields. The problem arises because most high-angle grain boundaries act like Josephson-coupled weak links. The characteristic properties of such junctions are a reduced zero-field Jct value and, more importantly, a strongly magnetic-field-dependent Jct that can decrease by more than an order of magnitude in even weak fields of a few millitesla (Fig. 1). Such Jct(H) characteristics are clearly a very serious problem for high-field magnet applications such as motors, generators, energy storage systems, and MRI machines.
Controlled Growth of High-Temperature Superconducting Thin Films on Polycrystalline Substrates
Authors: Shaw David T. 
Published: August 2016

Since their discovery in 1987, significant progress has been made in the fabrication of high-quality, high-temperature superconducting (HTS) thin films. Films with reproducible properties can be routinely deposited on single crystal substrates by several well-established processing techniques. Single crystal substrates, however, are not suitable for many applications because of their cost, limitations in size and shape, and lack of flexibility. Hence, a great deal of effort has been directed at the fabrication of thin films on polycrystalline rather than single crystal substrates. For example, metallic substrates are expected to be useful for the fabrication of HTS conductors for such applications as generators, motors, and superconducting magnetic energy storage (SMES) devices. For polycrystalline thin-film applications, lattice matching for epitaxial growth of thin films is no longer possible. Microstructures of these films are generally more complex than those of single crystal films, primarily because of grain boundaries. As a result, the microstructure of polycrystalline films must be carefully controlled to ensure that the critical current density is high enough for practical applications.Happily, progress in this respect has been substantial. There have been laboratory demonstrations of techniques for controlled processing of high-quality HTS thin films on polycrystalline substrates. Even though the technology development in this area is still in its infancy, many successful processing approaches have been developed to set the stage for the eventual use of HTS thin films in power device applications.