bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy‐Dispersive Spectrometry
Authors: Newbury Dale E. 
Published: October 2003

AbstractEnergy‐dispersive x‐ray spectrometry (EDS) is a technique for measuring the intensity of x‐ray emission as a function of the energy of the x‐ray photons. The excitation source for the x‐rays can be energetic electrons, photons, or ions, and the target can be solid, liquid, or gas, although solid targets are the norm in virtually all materials science applications. The measured x‐ray intensity can be related to the concentration (i.e., mass or atomic fraction) for each element present by performing physical/empirical matrix corrections to account for the interelement modification of the generated x radiation caused by (1) primary radiation stopping power and ionization effects, (2) attenuation of secondary characteristic x‐rays during their passage through matter, and (3) any inefficiencies in detection. In this article, various aspects of the process of obtaining high‐quality x‐ray spectra, the interpretation of spectra, and the accurate extraction of x‐ray intensities from spectra are considered.Materials analysis techniques that employ EDS include the following.Electron excitation: (1) electron probe x‐ray microanalysis (EPMA)/analytical scanning electron microscopy (ASEM), where EDS complements wavelength‐dispersive x‐ray spectroscopy (WDS); (2) analytical electron microscopy (AEM).Photon excitation:X‐ray fluorescence (XRF).Ion excitation:particle‐induced x‐ray emission (PIXE).This article will concentrate on EDS performed in electron‐beam instruments. The general principles of EDS x‐ray detection, processing, display, and spectral manipulation are similar for all analytical techniques regardless of the excitation source. The procedures for quantitative analysis depend in detail on the excitation process. Quantitative x‐ray microanalysis by electron excitation is considered in detail in the section on Electron Probe Microanalysis. Those aspects of quantitative x‐ray microanalysis that are particular to EDS spectral measurement are considered.
Trace Element Accelerator Mass Spectrometry
Authors: McDaniel Floyd Del 
Published: October 2003

AbstractAccelerator mass spectrometry is a relatively new analytical technique that is being used in over 40 laboratories worldwide for the measurements of cosmogenic long‐lived radioisotopes, as a tracer in biomedical applications, and for trace element analysis of stable isotopes. The use of particle accelerators, along with mass spectrometric methods, has allowed low‐concentration measurements of small‐volume samples. The use of AMS to directly count ions, rather than measure radiation from slow radioactive decay processes in larger samples, has resulted in sensitivities of one part in 1015. The ions are accelerated to mega‐electron‐volt energies and can be detected with 100% efficiency in particle detectors. The improved sensitivities and smaller sample sizes have resulted in a wide variety of applications in anthropology, archaeology, astrophysics, biomedical sciences, climatology, ecology, geology, glaciology, hydrology, materials science, nuclear physics, oceanography, sedimentology, terrestrial studies, and volcanology, among others. Accelerator mass spectrometry has opened new areas of research in the characterization of trace elements in materials.This article will focus is on the technique of trace element accelerator mass spectrometry (TEAMS) and its applications in the analysis of stable isotopes in materials.Trace element AMS employs a tandem electrostatic accelerator with the center terminal at a positive potential.Sensitivities for TEAMS measurements vary for different elements. These sensitivities depend on (1) the ability to form a negative atomic ion or a negatively charged molecule that can be accelerated to the terminal and then broken apart; (2) the charge state used for the measurements since the charge state (≥3+) must be chosen to remove molecular interferences; and (3) transmission of the ion from the sample through the accelerator and beamlines to the detector. By calibrating the secondary‐ion yield against reference standards and by measuring the depth of the sputtered crater, a quantified depth profile can be obtained. The sensitivity or detection limit depends on the amount or volume of material available to analyze. The sensitivity can be much better for bulk measurements, where the element of interest is uniformly dispersed throughout the material. Then, the sample can be run almost indefinitely until good statistics have been obtained. Typically, sensitivities of 0.1 part per billion (ppb) can be obtained in the depth‐profiling mode. Because sensitivities are so high, it is sometimes difficult to obtain suitable reference standards.
Introduction To Medium‐Energy Ion Beam Analysis
Authors: Weller Robert A. 
Published: October 2003

Abstract
The earliest applications of ion beam techniques for materials analysis, typified by the work of Tollestrup et al. (1994), were carried out with mega‐electron‐volt beams in the course of basic research in nuclear physics, and the mega‐electron‐volt beam techniques still form the indispensable core of the subject. In the broadest sense, the importance of these techniques lies in the fact that the information they yield depends upon nuclear properties and interactions and is, therefore, relatively insensitive to perturbation by local properties such as the chemical environment and electronic structure. The relevant nuclear physics and scattering theory are well known experimentally and often theoretically, and in consequence, important parameters such as interaction cross‐sections are known from first principles. This is in sharp contrast to the situation for some other important techniques (e.g., secondary ion mass spectrometry) where the fundamental measurement interactions may be very vulnerable to the unique idiosyncrasies of a specimen. It is essential to stress the unity of ion beam analysis even as one seeks to differentiate the relatively newer medium‐energy techniques from their more mature high‐energy predecessors.
First it is important to understand what is meant by “medium energy.” There are two answers, one historical and one based upon the physics of scattering. For practical purposes, medium energy encompasses ion beam energies from a few tens of to a few hundreds of kilo‐electron‐volts, and even a bit higher for heavy ions being used in forward‐recoil work. Below this range, ion scattering becomes increasingly surface specific. Above it lies the full range of conventional elastic scattering and nuclear reaction analysis.
Historically, medium energy has been defined by technology. The field of ion beam analysis owes its ubiquity, if not its existence, to a single device, the silicon surface‐barrier particle detector.
The articles in this category follow describe some medium‐energy ion beam analytical techniques that are optimized for different problems. Time‐of‐flight medium‐energy backscattering and forward‐recoil spectrometry, are quite similar to the high‐energy techniques of high‐energy ion beam analysis but offer increased depth resolution, sensitivity, and surface specificity at the expense of total analyzable depth and ease of use.
Heavy‐ion backscattering spectrometry is a variant of time‐of‐flight backscattering that is optimized for the highest possible sensitivity, specifically for the measurement of ultra‐low‐level metallic contaminants on device‐grade Si wafer surfaces. Along with total‐reflection x‐ray fluorescence spectrometry, it is the definitive method currently available for this measurement. Medium‐energy techniques are appropriate for specialized problems and circumstances as described in the articles.
Heavy‐Ion Backscattering Spectrometry
Authors: Banks James C. , Knapp James A. 
Published: October 2003

AbstractHeavy‐ion backscattering spectrometry (HIBS) is a new technique for nondestructively analyzing ultratrace levels of impurities on the surface of very pure substrates. Although any high‐Zcontaminant (Z≥ 18) on a pure low‐Zsubstrate can be measured, recent practical applications for HIBS have focused on measuring contaminants found on silicon wafers used in semiconductor manufacturing. Therefore, discussions of HIBS focus in this area. The technique is based on the same principles described for high‐energy Rutherford backscattering spectrometry (RBS) and medium‐energy ion backscattering spectrometry.The motivation for HIBS is to detect metallic contamination at levels significantly below those that can be detected by RBS or medium‐energy ion backscattering, both of which have a limit of ∼1 × 1013atoms/cm2for near‐surface impurities. It had been reported that contamination control in the microelectronics industry will require tools that can measure ∼1 × 1010atoms/cm2for transition metals in starting material. The detection limit for well‐separated elements on a clean Si surface ranges from ∼6 × 109atoms/cm2for Fe to ∼3 × 108atoms/cm2for Au, without the use of vapor phase decomposition (VPD) to preconcentrate the impurities. Using VPD would improve the sensitivity by at least an order of magnitude.The HIBS technique is illustrated Other surface analysis techniques for detection of trace element contamination are briefly discussed, with the strengths and weaknesses of each compared to those of HIBS. A detailed discussion of the basic theoretical and practical aspects of HIBS is provided.
Barrier Polymers
Authors: Dhoot Sushil N. , Freeman Benny D. , Stewart Mark E. 
Published: October 2003

AbstractAlthough broadly defined as a macromolecule having the ability to restrict the passage of gases, vapors, and liquids, the functional definition of a barrier polymer varies from application to application and a material that provides sufficient barrier for a particular end use can be considered to be a barrier polymer. They are widely used in food, beverage, and other packaging industries. Some of the advantages that they offer over traditional packaging materials such as glass, paper, and metals are flexibility, light weight, toughness, versatility, and printability. However, unlike glass and metals, no polymer offers an infinite gas barrier. Combinations of different polymers, or polymers with inorganic materials, in the form of multilayer structures or blends, can provide sufficient barrier for the intended shelf life of most products. Inorganic materials such as silicon and aluminum oxides and nanoclays can significantly enhance barrier and other mechanical properties of polymers. Other approaches for improving barrier properties such as oxygen‐scavenging systems have also received considerable attention in recent years. This article discusses various types of barrier polymers and structures, their permeability characteristics (including the underlying principles involved), measurement techniques, ways to predict and improve barrier properties, and current as well as potential future applications for barrier polymers.
Block Copolymers
Authors: Hamley I. W. 
Published: October 2003

AbstractThe synthesis, morphology, and dynamics of block copolymers in various states is reviewed. Living polymerization techniques used to prepare well‐defined diblock, triblock, and starblock copolymers are first summarized. Then the phase behavior of block copolymers in the melt is discussed, based on experimental and theoretical work. The effect of confinement on block copolymers in thin films is then considered. The behavior of block copolymers in solution and applications resulting from micelle formation are also reviewed. The effect of crystallization on block copolymer morphology is also outlined. Finally, the competing effects of micro‐ and macrophase separation in blends of polymers containing block copolymers is described, along with compatibilization of immiscible polymers by block copolymers.
Butadiene Polymers
Authors: Kerns Michael , Henning Steven , Rachita Michael 
Published: October 2003

AbstractThis article provides an overview of polybutadiene materials as a progression from the monomer 1,3‐butadiene to a useful polymer product with a wide range of applications. A brief history of polybutadiene, with its development as a highcis‐polybutadiene material during World War I through its present day use as a high vinyl substitute for styrene–butadiene rubber is included. The structure and properties of the monomer are presented, along with monomer manufacture, typical specifications, and health and safety issues. Following a detailed discussion on both polymer microstructure and macrostructure, there is an in‐depth review of polymerization methods that are typically used to produce polybutadiene. The state‐of‐the‐art in free‐radical, Ziegler–Natta, anionic, and cationic polymerization techniques that produce polybutadiene are thoroughly discussed in terms of the influence of catalyst/initiator technology on microstructure and the resulting relationship between microstructure and applications. The most popular commercial polymerization processes are also reviewed including solution, emulsion, and an introduction to gas‐phase polybutadiene polymerization technology. Finally, the economic aspects of polybutadiene materials are presented, including major producers, capacities, and pricing.
Cellulose Esters, Inorganic
Authors: Shelton Michael C. 
Published: October 2003

AbstractInorganic esters of cellulose have a valuable place in history, from the birth of the plastics industry to elucidation of the genetic code. It is important not to forget the large number of applications in which these materials have played a role: coatings, explosives, pharmaceuticals, membranes, and synthetic intermediates. Although inorganic esters of cellulose have been around for over 100 years, these materials remain important tools for coatings scientists, explosives experts, and biochemists. This article provides a summary of work on inorganic esters of cellulose, including cellulose nitrate, cellulose phosphate, cellulose sulfate, and cellulose sulfonates.
Cellulose Ethers
Authors: Majewicz Thomas G. , Erazo‐Majewicz Paquita E. , Podlas Thomas J. 
Published: October 2003

AbstractCellulose ethers is the common terminology for a group of cellulose derivatives that are soluble in aqueous or organic media. They are additives in many formulations and function primarily to control solution rheology. This article surveys the chemistry, properties, and characterization methods common to cellulose ethers and their manufacture and provides general health and safety factors. In the discussion of commercial cellulose ethers, greater detail for individual cellulose ether compositions, including carboxymethylcellulose, hydroxyethylcellulose and its mixed ethers, methylcellulose and its mixed ethers, ethylcellulose, hydroxyethylethylcellulose, and hydroxypropylcellulose is offered.
Chromatography, Affinity
Authors: Scouten William H. 
Published: October 2003

AbstractAffinity chromatography a rapid and highly efficient means of protein purification utilizing the highly selective ability of enzymes to recognize certain biological compounds or their analogues. This technique involves the immobilization of an appropriate ligand in such a way that the enzyme is still capable of recognizing and binding to the immobilized form of the ligand, whereas contaminating proteins have no such recognition. Virtually hundreds of proteins have been purified in this way, using a wide variety of bioligands immobilized in a matrix; enzyme inhibitors, coenzymes, antibodies, and even other enzymes may be useful bioligands in the purification of a particular protein. This article discusses ligands, matrices, and applications of this separation and purification technique.
Chromatography,
HPLC
Authors: Brun Yefim 
Published: October 2003

Abstract
A comprehensive review of high performance liquid chromatography (hplc) of biological and synthetic polymers is presented. Instrumentation, individual modes of separation, theoretical background (both thermodynamic and dynamic factors), and applications are discussed. High performance liquid chromatography is widely used for isolation and purification of biopolymers and analysis of additives in complex polymer formulations. The potential of hplc for bioseparations is analyzed in the light of recent development in reversed‐phase, hydrophobic‐interaction, and ion‐exchange chromatographies. Miniaturization of separation and other problems related to coupling column chromatography to mass spectrometer detection, as well as multidimensional separations, are considered in some detail.
High performance liquid chromatography is a powerful tool for characterization of synthetic and natural polymers by separating individual fractions by molecular weight, chemical composition, functional groups, etc. Normal‐ or reversed‐phase gradient separation of synthetic copolymers and polymer blends provides information about polymer's chemical composition distribution, and is considered as a technique complimentary to size‐exclusion chromatography. Two‐dimensional copolymer characterization is achieved by coupling two different modes of chromatographic separation consequently, which can result in determination of both molecular weight and chemical composition distributions of synthetic copolymers.
Coating Methods, Powder Technology
Authors: Richart Douglas S. 
Published: October 2003

AbstractMethods for applying decorative and protective coatings utilizing finely divided powders followed by heat fusion of the powder particles to form a continuous film are gaining in popularity and commercial acceptance. Since there are no volatile organic compounds present, powder coating is an environmentally friendly, nonpolluting coating process, providing coatings with improved performance as well. Powder coatings can be found on many common items including lawn and garden equipment, outdoor metal furniture, display racks, architectural aluminum panels and trim, and many automotive components including the exterior clear coat.The chemistry and composition of powders used in coatings and their properties are described, as well as their method of manufacture, processes used to apply them, their applications, and a review of health, safety, and environmental considerations. Over 100 references are supplied to provide more detailed technical information.
Coating Methods, Survey
Authors: Cohen Edward D. , Gutoff Edgar B. 
Published: October 2003

Abstract
Coating process technology is used to produce a wide variety of products, such as surface coatings to protect houses, bridges, and automobiles; packaging materials to store food; adhesives for use in labels; photographic films; optical and magnetic media for audio and visual use data storage; glossy paper for magazines; and printing plates. The coating machine, which produces the coated web, has several steps. The web is unwound and transported through the coater, then a coating applicator applies the coating which is then solidified, and finally the web is rewound. The coating machine can also contain devices to modify the surface properties, to clean the web, to measure coating weight, and to laminate a second web to the structure.
Many of the commercially available coating applicators are described, including units for simultaneous multilayer application, for discrete coating, and for patch coating. While convection drying is emphasized, brief descriptions of conduction and infrared heating, as well as of uv and electron‐beam curing, are given.
Collagen
Authors: Ramshaw John A. M. , Glattauer Veronica , Werkmeister Jerome A. 
Published: October 2003

AbstractCollagen is the most abundant animal protein, being the principal protein component of all connective tissues, including skin, bone, tendon, and cartilage. There are at least 21 distinct collagen types. All play a structural and/or functional role in the extracellular matrix. All are characterized by the triple‐helical structure, which leads to a repeating Gly‐X‐Y amino acid sequence. Each collagen chain has a precise, genetically determined molecular size, which may be further modified during biosynthesis by a range of secondary modification processes. In functional tissues the major collagens form into ordered, cross‐linked fibrils. Minor collagens display a range of other aggregate structures. Collagens can be prepared from a variety of tissue sources, and are now available as recombinant proteins. Test methods are available for quantitation and for assessing purity, stability, and biological properties. Collagen is a valuable and widely used polymer in manufactured products, including leather and gelatin. A growing market is emerging for collagen in a range of biomedical applications. The long history of successful applications for collagen indicates that it is a safe material.
Cotton
Authors: Wakelyn Phillip J. 
Published: October 2003

AbstractCotton is both a fiber and a food crop that is grown in about 80 countries. Annually in the world about 90 million 217.7‐kg (480‐lb) bales [∼19.6 million metric tons (21.6 million tons)] of cotton fiber and 27 million metric tons (29.8 million tons) of cottonseed are produced. Cotton is the most important natural fiber (about 37% of the textile fiber consumed in the world in 2002) used to produce apparel, home furnishings, and industrial products. Cottonseed is the world's no. 3 oilseed, used for vegetable oil, animal feed, and linters. Over 90% of the world's cotton production is upland cotton (Gossypium hirsutum) and about 8% is extra long staple (G. barbadense). In 2002 transgenic varieties are about 25–30% of the cotton grown in the world. Commercial cottons are white. There has been some interest in naturally colored cottons (shades of brown and green are the main colors) and organic cotton but, at present, there is very little production of these cottons [<20,000 bales worldwide; <4455 t (4800 tons)]. The origin, biosynthesis, biology, development, production, harvesting ginning, classification, physical properties, morphology, physical structure, chemistry, reactivity, economic aspects, utilization, and health and safety are reviewed.
Critical Phase Polymerizations
Authors: Jones Charles A. , DeSimone Joseph M. 
Published: October 2003

AbstractCarbon dioxide is a versatile, environmentally benign solvent for the synthesis of many polymeric materials. This review focuses on recent advances in the utilization of liquid and supercritical CO2as a reaction medium for polymer synthesis. Polymerization techniques with both chain‐growth and step‐growth mechanisms are discussed, including free‐radical, metal‐catalyzed, ionic, and bulk polycondensation processes.
Diacetylene and Triacetylene Polymers
Authors: Fowler Frank 
Published: October 2003

AbstractThe polyacetylenes, polydiacetylenes, and polytriacetylenes are the only known families of linearly conjugated polymers. The polydiacetylenes and polytriacetylenes, the primary topic of this discussion, are distinguished from the polyacetylenes because they require preorganization of the monomer for a successful polymerization. These topochemically controlled polymerizations have the interesting property that they can lead to single crystals of conjugated polymers, a unique structural feature among all polymers. The conjugated backbones impart interesting optical and electrical properties to these polymers, making them possible candidates for the development of advanced materials.