bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen in Nanostructured, Carbon-Related, and Metallic Materials
Authors: Züttel Andreas , Orimo Shin-ichi 
Published: February 2011

AbstractRecent developments in hydrogen interaction with carbonaceous materials are reviewed in this article. The interaction is based on van der Waals attractive forces (physisorption), or the overlap of the highest occupied molecular orbitals of carbon with the hydrogen electron, overcoming the activation-energy barrier for hydrogen dissociation (chemisorption). While the physisorption of hydrogen limits the hydrogen-to-carbon ratio to less than one hydrogen atom per two carbon atoms (i.e., 4.2 mass%), in chemisorption, a ratio of two hydrogen atoms per one carbon atom is realized (e.g., in polyethylene). However, the materials with large hydrogen-to-carbon ratios only liberate the hydrogen at elevated temperature. No evidence, apart from theoretical calculations, was found for a new hydrogen-adsorption phenomenon on carbon nanotubes (CNTs), as compared with high-surface-area graphite. The curvature of CNTs and fullerenes increases the reactivity of these materials with hydrogen and leads more easily to the formation of hydrocarbons, as compared with graphite. Nanocrystalline or amorphous carbon exhibits an intermediate state for hydrogen between physisorption and chemisorption and absorbs up to one hydrogen atom per carbon atom. Nanostructured carbonaceous and metallic materials offer a large potential for hydrogen storage and must therefore be investigated in more detail.
Advances in Chemical-Mechanical Planarization
Authors: Singh Rajiv K. , Bajaj Rajeev 
Published: February 2011

AbstractThe primary aim of this issue of MRS Bulletin is to present an overview of the materials issues in chemical–mechanical planarization (CMP), also known as chemical–mechanial polishing, a process that is used in the semiconductor industry to isolate and connect individual transistors on a chip. The CMP process has been the fastest-growing semiconductor operation in the last decade, and its future growth is being fueled by the introduction of copper-based interconnects in advanced microprocessors and other devices. Articles in this issue range from providing a fundamental understanding of the CMP process to the latest advancements in the field. Topics covered in these articles include an overview of CMP, fundamental principles of slurry design, understanding wafer–pad–slurry interactions, process integration issues, the formulation of abrasive-free slurries for copper polishing, understanding surface topography issues in shallow trench isolation, and emerging applications.
The Future of CMP
Authors: Evans David 
Published: February 2011

AbstractChemical–mechanical polishing, or planarization (CMP), is one of several advanced microfabrication processes that provide complementary capabilities for constructing advanced electronic devices. At the current state of the art, CMP demonstrates significant advantages due to its high degree of process flexibility, particularly in the chemical formulation of polishing solutions and slurries. This article explores some possible future applications of CMP using new advanced materials other than silicon, silicon oxide, and silicon nitride. Such materials may include refractory and noble metals, high-κ insulators, and mixed metal oxide perovskites. Although no one can predict future applications with absolute certainty, it seems safe to conclude that CMP will remain a key microfabrication technology for the foreseeable future.
On the Road to an Atomic- and Molecular-Level Understanding of Friction
Authors: Mathew Mate C. 
Published: February 2011

AbstractThe following article is an edited transcript based on the MRS Medal presentation given by C. Mathew Mate of IBM Almaden Research Center on November 29, 2001, at the Materials Research Society Fall Meeting in Boston. Mate received the Medal for his “pioneering studies of friction at the atomic and molecular levels.” This presentation describes some of his efforts at understanding friction at the atomic level. The starting point for the author was the invention of the friction force microscope and the first observation of atomic-scale friction in 1987. Soon afterward came other applications of force microscopy, leading toward a greater understanding of friction, lubrication, and wear. These studies also have had an impact on the understanding of lubricant films in disk drives and are now aiding the development of nanoscale devices such as the “molecular raft,” an 8-Å-thick island of squalane floating on a thicker squalane film that could potentially be used to transport nanoscale objects.
Reverse Engineering: Learning from Proteins How to Enhance the Performance of Synthetic Nanosystems
Authors: Vogel Viola 
Published: February 2011

AbstractProteins are nature's workhorses. They enable living systems to use available energy sources and convert energy from one form into another. Understanding the underlying design principles of how proteins have evolved to fulfill the necessary functions of life can provide researchers with new insights into how to enhance the performance of synthetic nanosystems with far greater sophistication. This review summarizes the relationship between various protein functions and the underlying engineering principles of their overall structures. For example, proteins can specifically recognize other biomolecules with a selectivity and affinity several orders of magnitude superior to their synthetic counterparts. Mimicking a protein binding site with a structurally fixed synthetic analogue is insufficient, since structural changes in the active sites enhance molecular recognition and the catalytic activity of proteins. Recent data also show that protein function can be switched by stretching proteins into nonequilibrium states under physiological conditions. Schemes by which the exposure and structure of recognition sites are switched can be implemented in the design of mechanically responsive synthetic and hybrid systems. Motor proteins, finally, are the jewel in nature's crown, as they can convert one free-energy form into another to generate mechanical force. It is thus of considerable interest to integrate the chemically powered engines into synthetic materials and devices. Finally, we have to advance our ability to assemble nanocomponents into functional systems. Again, lessons can be learned from how biology solves the challenge of systems integration.
Ancient and Modern Steels and Laminated Composites Containing Steels
Authors: Wadsworth Jeffrey 
Published: February 2011

AbstractA class of steels (ultrahigh-carbon steels, or UHCSs) containing high levels of carbon (i.e., ∼1–2 wt%) were originally developed for their superplastic characteristics. In combination with excellent room-temperature properties, the steels were developed for their commercial potential starting in the mid-1970s and continuing to the present time. The compositional similarities between these modern steels and ancient Damascus steels led to a revisiting of the history and metallurgy of Damascus and related steels. Also, as part of the development of UHCSs, modern laminated composites containing them have been designed and manufactured that have unique toughness characteristics. These laminated composites also have similarities to a range of laminated materials of historical interest. Finally, some comments are made on the utility of radiocarbon dating to determine the age of ancient irons and steels. Ten sidebars supplement this article as Web Extras on the MRS Bulletin Web site at www.mrs.org/publications/bulletin/2002/dec/.
Giant Magnetostriction in Ferromagnetic Shape-Memory Alloys
Authors: Kakeshita Tomoyuki , Ullakko Kari 
Published: February 2011

AbstractShape-memory alloys are now widely used because they exhibit a large recoverable strain, which is caused by the conversion of variants in the martensite phase. The conversion of variants is usually promoted by the application of external stress. Recently, however, it was found that the conversion of variants can also be promoted by the application of a magnetic field to induce the martensitic state in ferromagnetic Ni2MnGa shape-memory alloys. Since then, the research in this field has focused considerable attention on applications for using the materials as actuators and sensors because their response to a magnetic field is much faster than their response to heating or cooling. Furthermore, the mechanism of the conversion of variants by the magnetic field has attracted academic interest from many researchers. In this article, we show giant magnetostrictive behavior in three ferromagnetic shape-memory alloys—Ni2MnGa, Fe-Pd, and Fe3Pt—and review the investigations performed so far by many researchers, including the present authors.
New Directions in Photopolymerizable Biomaterials
Authors: Anseth Kristi S. , Burdick Jason A. 
Published: February 2011

AbstractThis article is based on the Outstanding Young Investigator Award presentation given by Kristi S. Anseth at the 2001 MRS Spring Meeting on April 17, 2001, in San Francisco. Anseth was recognized for “innovative work in polymeric biomaterials for drug delivery, bone and cartilage repair, and tissue engineering, and for outstanding leadership potential in this interdisciplinary field of materials research.”Photopolymerization provides many advantages as a technique for the fabrication of biomaterials. Temporal and spatial control, along with the diversity in material properties found with photopolymerizable materials, are advantageous in the biomaterials industry. For instance, multifunctional anhydride monomers form highly cross-linked surface-eroding networks directly in bone defects. These networks have good mechanical properties that are maintained with degradation and have the potential to restore tissue-like properties to bone during the healing process. Additionally, cartilage-forming cells photoencapsulated in hydrogel networks secrete an extracellular matrix as the hydrogel is resorbed and may provide a treatment alternative for cartilage defects that do not heal spontaneously. Finally, transdermal polymerization (photopolymerization through the skin) of multifunctional monomers is a noninvasive technique that is being developed for tissue regeneration and wound-healing applications.
Alternative Gate Dielectrics for Microelectronics
Authors: Wallace Robert M. , Wilk Glen 
Published: February 2011

AbstractThis brief article sets the context for the March 2002 issue of MRS Bulletin focusing on Alternative Gate Dielectrics for Microelectronics. Contributors are several experts from industry and academia engaged in the search for manufacturable solutions for a suitable alternative gate dielectric to SiO2 using high-dielectric-constant (high-ĸ) materials. Issues discussed in the articles include thermodynamics criteria for materials selection, materials interactions in the construction of the transistor gate stack, characterization of alternative materials, determination of suitable band offsets for candidate dielectrics, and integration of these alternative gate dielectrics in a manufacturable environment.
Compatibility Challenges for High-ĸ Materials Integration into CMOS Technology
Authors: Guha Supratik , Gusev Evgeni , Copel Matthew , Ragnarsson Lars-Åke , Buchanan Douglas A. 
Published: February 2011

AbstractIn addition to meeting the formidable challenges of replacing the nearly perfect SiO2 dielectric, a new dielectric ideally needs to replace SiO2 with minimal rearrangement of the complementary metal oxide semiconductor (CMOS) process flow. In this article, we outline the essential materials-integration issues that arise out of the technical requirements for minimizing changes to future process technologies. These include interfacial layer formation, film microstructure, deposition technologies, and electrical performance challenges such as trapped charge and the mobility degradation associated with any replacement material. Integration of the high-ĸ materials currently under consideration presents a significant challenge for materials scientists and engineers in industry and academia.
Combinatorial Screening and Optimization of Luminescent Materials and Organic Light-Emitting Devices
Authors: Sun Ted X. , Jabbour G.E. 
Published: February 2011

AbstractThe rapid development of modern photonic technologies—for example, mercury-free lamps, flat-panel displays, and solid-state lamps—demands the timely discovery of advanced phosphors. A combinatorial process has been developed to dramatically accelerate the experimental search for such phosphors. High-density phosphor “libraries” containing from 100 to over 1000 discrete chemical compositions on a 1 in. × 1 in. substrate have been made in thin-film or powder form using selective vapor deposition and liquid-dispensing techniques, respectively. In this article, the existing methods of combinatorial synthesis and screening of phosphors will be reviewed with examples. These methods may also be used to screen organic-based solid-state materials and optimize their device properties. In this regard, combinatorial and spreading techniques have been utilized to study and rapidly optimize organic light-emitting devices (OLEDs).
Continuous Phase Diagramming of Epitaxial Films
Authors: Yoo Young K. , Tsui Frank 
Published: February 2011

AbstractHigh-throughput and systematic studies of complex materials systems using the approach of “continuous phase diagramming” (CPD) are described in this article. The discussions focus on the techniques of epitaxial film synthesis of CPD and mapping physical and structural properties, using two different material systems as examples: doped perovskite manganese oxides and magnetic alloys. In doped perovskite manganese oxides, a highly correlated system, mapping the optical, electrical, and magnetic properties, reveals surprising evidence of electronic phase transitions that correlate with the low-temperature magnetic order. In magnetic alloys, application of CPD, particularly using real-time characterization during epitaxial growth, makes it possible to examine structure–property relations systematically.
Material Aspects of Standard Transmission Optical Fibers
Authors: Guenot P. 
Published: February 2011

AbstractThis article reviews loss components of standard transmission silica optical fibers and their connections to glass structure and manufacturing parameters. Loss-reduction possibilities are described. In particular, the Rayleigh scattering component, which is the main contributor to fiber losses within the transmission window, can be significantly reduced by lowering the fictive temperature (the temperature at which the liquid structure is “frozen” during cooling) and tuning the glass composition. The issue of a compromise between manufacturing productivity and minimization of excess loss is also addressed.
Materials Science of Adhesives: How to Bond Things Together
Authors: Creton Costantino , Papon Eric 
Published: February 2011

AbstractThis issue of MRS Bulletin provides an overview of the state of the art and emerging trends in the area of adhesives. An adhesive is basically defined by its function, which is to assemble two surfaces together. In order to fulfill this function, the properties of an adhesive must include easy positioning at the interface, rapid and complete bond formation and subsequent hardening, and a bond strength adapted to the specific application (structural, permanent, removable, rigid, or soft). A variety of solutions exist in practice, and their application requires an understanding both of polymer chemistry and materials science. The main families of adhesives, their properties, and their basic design principles will be discussed in the articles in this issue, while this introductory article presents an overview of the functions required of adhesives and future trends.
Pressure-Sensitive Adhesives: An Introductory Course
Authors: Creton Costantino 
Published: February 2011

AbstractSelf-adhesive materials are called, in the adhesives trade, “pressure-sensitive adhesives” (PSAs). PSAs are designed to stick on almost any surface by simple contact under light pressure. This special class of adhesives does not undergo any physical transformation or chemical reaction during the bonding process. Because of this, the rheological properties of the adhesive must be finely tuned for the application, combining a carefully chosen polymer architecture and monomer composition with the proper addition of small molecules called tackifying resins. PSAs are soft, deformable solids and, depending on the formulation, easily form bridging fibrils between two surfaces upon debonding. They are safe to use and easy to handle and thus are increasingly replacing more conventional types of adhesives. In this article, we review both the primary material characteristics of PSAs and the main physical principles that make them work effectively.
Nanoscale Science and Technology: Building a Big Future from Small Things
Authors: Lieber Charles M. 
Published: February 2011

AbstractThe following article is an edited transcript based on the MRS Medalist presentation given by Charles M. Lieber of Harvard University on December 4, 2002, at the Materials Research Society Fall Meeting in Boston. Lieber received the Medal “for controlled synthesis of nanowire and nanotube materials.” This presentation begins with an introduction to the bottom-up paradigm of nanoscience and nanotechnology. The key concepts of this paradigm are explored through studies outlining progress toward meeting the challenge of nanocomputing through the assembly of functional nanowire elements. The richness of the bottom-up paradigm and nanowire building blocks is then illustrated with the development of chemical and biological nanosensors. Finally, the uniqueness of nanowires is exemplified through discussion of the assembly of nanophotonic devices, including the demonstration of multicolor and addressable nanoscale light-emitting diodes, nanowire injection lasers, and assembled arrays of these nanophotonic sources. Challenges and goals for realizing nanotechnologies in the future are discussed in the conclusion.
The Art and Materials Science of 190-mph Superbikes
Authors: Falco Charles M. 
Published: February 2011

AbstractThe following article is an edited transcript of a talk presented in Symposium X—Frontiers of Materials Research at the 2002 Materials Research Society Fall Meeting in Boston on December 2, 2002. From Bessemer steel used on the first motorized bicycle in 1871 to sintered aluminum ceramic composites and TiN thin-film coatings used on standard production machines today, motorcycles have been at the forefront of the use of high-performance materials. Thanks to developments in materials technology, relatively inexpensive mass-produced motorcycles are now capable of achieving speeds of >190 mph.
Chemical and Biological Protection and Detection in Fabrics for Protective Clothing
Authors: Schreuder-Gibson Heidi L. , Truong Quoc , Walker John E. , Owens Jeffery R. , Wander Joseph D. , Jones Wayne E. 
Published: February 2011

AbstractMilitary, firefighter, law enforcement, and medical personnel require high-level protection when dealing with chemical and biological threats in many environments ranging from combat to urban, agricultural, and industrial. Current protective clothing is based on full barrier protection, such as hazardous materials (HAZMAT) suits, or permeable adsorptive protective overgarments, such as those used by the U.S. military. New protective garment systems are envisioned that contain novel features, such as the capability to selectively block toxic chemicals, to chemically destroy toxic materials that contact the fabric, and to detect hazardous agents on the surface of the fabric. New technologies being built into advanced fabrics for enhanced chemical and biological protection include selectively permeable membranes, reactive nanoparticles, reactive nanofibers, biocidal fabric treatments, and conductive-polymer indicators on optical fibers.
Assessment of New High-Performance Fibers for Advanced Applications
Authors: Sikkema Doetze J. , Northolt Maurits G. , Pourdeyhimi Behnam 
Published: February 2011

AbstractHigh-performance fibers, used in fabric applications ranging from bulletproof vests to trampolines, must have a sufficient number of chemical and physical bonds for transferring the stress along the fiber. To limit their deformation, the fibers should possess high stiffness and strength. Stiffness is brought about by the degree to which the chemical bonds are aligned along the fiber axis. In fiber-reinforced composites, the fibers are the load-bearing element in the structure, and they must adhere well to the matrix material. An ideal reinforcing fiber must have high tensile and compressive moduli, high tensile and compressive strength, high damage tolerance, low specific weight, good adhesion to the matrix materials, and good temperature resistance. This article reviews and compares the properties and behavior of novel high-performance fiber materials including polyethylene, aramid, polybenzobisoxazole, M5, and carbon fibers.
Low-Cost Wafer-Level Vacuum Packaging for MEMS
Authors: Gooch Roland , Schimert Thomas 
Published: February 2011

AbstractVacuum packaging of high-performance surface-micromachined uncooled microbolometer detectors and focal-plane arrays (FPAs) for infrared imaging and nonimaging applications, inertial MEMS (microelectromechanical systems) accelerometers and gyroscopes, and rf MEMS resonators is a key issue in the technology development path to low-cost, high-volume MEMS production. In this article, two approaches to vacuum packaging for MEMS will be discussed. The first is component-level vacuum packaging, a die-level approach that involves packaging individual die in a ceramic package using either a silicon or germanium lid. The second approach is wafer-level vacuum packaging, in which the vacuum-packaging process is carried out at the wafer level prior to dicing the wafer into individual die. We focus the discussion of MEMS vacuum packaging on surface-micromachined uncooled amorphous silicon infrared microbolometer detectors and FPAs for which both component-level and wafer-level vacuum packaging have found widespread application and system insertion. We first discuss the requirement for vacuum packaging of uncooled a-Si microbolometers and FPAs. Second, we discuss the details of the component-level and wafer-level vacuum-packaging approaches. Finally, we discuss the system insertion of wafer-level vacuum packaging into the Raytheon 2000AS uncooled infrared imaging camera product line that employs a wafer-level-packaged 160 × 120 pixel a-Si infrared FPA.
New Materials for Spintronics
Authors: Chambers Scott A. , Yoo Young K. 
Published: February 2011

AbstractThis article introduces the October 2003 issue of MRS Bulletin on “New Materials for Spintronics.” As a result of quantum mechanics, the carriers in ferromagnetic metals such as Fe, Co, and Ni are spin-polarized due to an imbalance at the Fermi level in the number of spin-up and spin-down electrons. A carrier maintains its spin polarization as long as it does not encounter a magnetic impurity or interact with the host lattice by means of spin-orbit coupling. The discovery of optically induced, long-lived quantum coherent spin states in semiconductors has created a range of possibilities for a new class of devices that utilize spin. This discovery also points to the need for a wider range of spin-polarized materials that will be required for different device configurations. In this issue of MRS Bulletin, we focus on three classes of candidate spintronic materials and review the current state of our understanding of them: III–V and II–VI semiconductors, oxides, and Heusler alloys. The field of spin-polarized materials is growing very rapidly, and the search for new magnetic semiconductors and other suitable spin-injection materials with higher Curie temperatures is bringing spintronics closer to the realm of being practical.