bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Semiconductor Devices with Enhanced Field and Environmental Responses for Novel Applications
Authors: Someya Takao , Pal Bholanath , Huang Jia , Katz Howard E. 
Published: February 2011

AbstractWe discuss some recent advances in the use of organic semiconductor devices with additional or enhanced functionality beyond simple electrical switching. These include diodes that act as local temperature sensors or that filter reverse-bias currents at tens of megahertz frequency. Transistors are described with a range of sensing and reporting functions, for such properties as pressure, magnetic field, and chemical vapor. Because these devices will likely be employed in arrays and assemblies, we also present concepts of some larger, integrated components such as artificial skin, sensor arrays, and wireless power systems. The common theme of these devices is that they build on an extensive and growing understanding of the parent transistors and diodes, but represent a departure into new physical phenomena and application areas.
Superhydrophobicity and Contact-Line Issues
Authors: Gao Lichao , Fadeev Alexander Y. , McCarthy Thomas J. 
Published: February 2011

AbstractThe wettability of several superhydrophobic surfaces that were prepared recently by simple, mostly single-step methods is described and compared with the wettability of surfaces that are less hydrophobic. We explain why two length scales of topography can be important for controlling the hydrophobicity of some surfaces (the lotus effect). Contact-angle hysteresis (difference between the advancing, θA, and receding, θR, contact angles) is discussed and explained, particularly with regard to its contribution to water repellency. Perfect hydrophobicity (θA/θR = 180°/180°) and a method for distinguishing perfectly hydrophobic surfaces from those that are almost perfectly hydrophobic are described and discussed. The Wenzel and Cassie theories, both of which involve analysis of interfacial (solid/liquid) areas and not contact lines, are criticized. Each of these related topics is addressed from the perspective of the three-phase (solid/liquid/vapor) contact line and its dynamics. The energy barriers for movement of the three-phase contact line from one metastable state to another control contact-angle hysteresis and, thus, water repellency.
Design Parameters for Superhydrophobicity and Superoleophobicity
Authors: Tuteja Anish , Choi Wonjae , McKinley Gareth H. , Cohen Robert E. , Rubner Michael F. 
Published: February 2011

AbstractRecent experiments have revealed that the wax on the lotus leaf surface, by itself, is weakly hydrophilic, even though the lotus leaf is known to be superhydrophobic. Conventional understanding suggests that a surface of such waxy composition should not be able to support superhydrophobicity and high contact angles between a liquid and the surface. Here, we show that the unexpected superhydrophobicity is related to the presence of “reentrant texture” (that is, a multivalued surface topography) on the surface of the lotus leaf. We exploit this understanding to enable the development of superoleophobic surfaces (i.e., surfaces that repel extremely low-surface-tension liquids, such as various alkanes), where essentially no naturally oleophobic materials exist. We also develop general design parameters that enable the evaluation of the robustness of the composite interface on a particular surface. Based on these design parameters, we also rank various superhydrophobic and superoleophobic substrates discussed in the literature, with particular emphasis on surfaces developed from inherently hydrophilic or oleophilic materials.
The Underlying Chemistry of Self-Healing Materials
Authors: Williams Kyle A. , Dreyer Daniel R. , Bielawski Christopher W. 
Published: February 2011

AbstractOver the past ten years, a broad range of self-healing materials, systems that can detect when they have been damaged and heal themselves either spontaneously or with the aid of a stimulus, has emerged. Although many unique compositions and components are used to create these materials, they all employ basic chemical reactions to facilitate repair processes. Kinetically controlled ring-opening reactions and reversible metal–ligand interactions have proven useful in autonomic self-healing materials, which require no stimulus (other than the formation of damage) for operation. In contrast, nonautonomic self-healing materials, which require some type of externally applied stimulus (such as heat or light) to enable healing functions, have capitalized on chemistries that utilize either reversible covalent bonds or various types of noncovalent interactions. This review describes the underlying chemistries used in state-of-the-art self-healing materials, as well as those currently in development.
Nanostructured Materials in Information Storage
Authors: Bandić Zvonimir Z. , Litvinov Dmitri , Rooks M. 
Published: February 2011

AbstractThe ever-increasing demand for information storage has pushed research and development of nonvolatile memories, particularly magnetic disk drives and silicon-based memories, to areal densities where bit sizes are approaching nanometer dimensions. At this level, material and device phenomena make further scaling increasingly difficult. The difficulties are illustrated in the examples of magnetic media and flash memory, such as thermal instability of sub-100-nm bits in magnetic memory and charge retention in flash memory, and solutions are discussed in the form of patterned media and crosspoint memories. The materials-based difficulties are replaced by nanofabrication challenges, requiring the introduction of new techniques such as nanoimprinting lithography for cost-effective manufacturing and self-assembly for fabrication on the sub-25-nm scale. Articles in this issue describe block-copolymer lithographic fabrication of patterned media, materials studies on the scaling limits of phase-change-based crosspoint memories, nanoscale fabrication using imprint lithography, and biologically inspired protein-based memory.
Patterned Magnetic Media Made by Self-Assembled Block-Copolymer Lithography
Authors: Ross C.A. , Cheng J.Y. 
Published: February 2011

AbstractPatterned magnetic recording media, in which data bits are stored in discrete single-domain magnetic particles, have been proposed for the next generation of recording media. To achieve high densities, features with periodicities on the order of 25 nm and below are required over large areas, which is a challenging task for any lithography process. Block copolymers (BCPs), which phase-separate into ordered periodic nanoscale structures, might provide a path to accomplish such patterning. In this article, we describe BCP lithography and show how the self-assembled patterns can be templated to make large-area arrays of nanoscale structures with long-range order.
Nanoscale Manufacturing Enabled by Imprint Lithography
Authors: Sreenivasan S.V. 
Published: February 2011

AbstractImprint lithography has a remarkable patterning resolution of less than 5 nm, and it is simultaneously capable of patterning over large areas with long-range order. This combination enables a broad range of potential applications including terabit-density magnetic storage, CMOS integrated circuits, and nanowire molecular memory. This article provides a review of the status of imprint lithography for nanoscale manufacturing. First, representative nanoscale devices and their manufacturing requirements are reviewed, along with key patterning challenges that have to be overcome to enable these nanoscale applications. Two classes of top–down nanopatterning techniques, namely, photon-based lithography and proximity mechanical nanopatterning (including imprint lithography), are described, followed by the three primary building blocks of imprint lithography: imprint masks, tools, and materials. Theresults of the lithography process are detailed in terms of process data such as long-range order in the placement and size of the nanostructures, process throughput, and overall cost considerations.
Protein-Based Disk Recording at Areal Densities beyond 10 Terabits/in.2
Authors: Khizroev S. , Ikkawi R. , Amos N. , Chomko R. , Renugopalakrishnan V. , Haddon R. , Litvinov D. 
Published: February 2011

AbstractThe concept of optical protein-based memory has been of interest since the early 1970s. Yet, no commercially available protein-based memory devices exist. This review presents an analysis of the main challenges associated with the practical implementation of such devices. In addition, the discussion includes details on the potential of using the unparalleled properties of photochromic proteins by creating an optical data storage disk drive with unmatched features and, particularly, record-high data densities and rates.
Negative Refraction in Photonic Crystals
Authors: Baba Toshihiko , Asatsuma Tomohiko , Matsumoto Takashi 
Published: February 2011

AbstractPhotonic crystals are multidimensional periodic gratings, in which the light propagation is dominated by Bragg diffraction that appears to be refraction at the flat surfaces of the crystals. The refraction angle from positive to negative, perfectly or only partially obeying Snell's law, can be tailored based on photonic band theory. Negative refraction enables novel prism, collimation, and lens effects. Because photonic crystals usually consist of two transparent media, these effects occur at absorption-free frequencies, affording significant design flexibility for free-space optics. The photonic-crystal slab, a high-index membrane with a two-dimensional airhole array, must be carefully designed to avoid unwanted reflection and diffraction. Light focusing based on negative refraction forms a parallel image of a light source, facilitating optical couplers and condenser lenses for wavelength demultiplexing. A compact wavelength demultiplexer can be designed by combining the prism and lens effects.
Two-Dimensional Electron Gases at Oxide Interfaces
Authors: Mannhart J. , Blank D.H.A. , Hwang H.Y. , Millis A.J. , Triscone J.-M. 
Published: February 2011

AbstractTwo-dimensional electron gases (2DEGs) based on conventional semiconductors such as Si or GaAs have played a pivotal role in fundamental science and technology. The high mobilities achieved in 2DEGs enabled the discovery of the integer and fractional quantum Hall effects and are exploited in high-electron-mobility transistors. Recent work has shown that 2DEGs can also exist at oxide interfaces. These electron gases typically result from reconstruction of the complex electronic structure of the oxides, so that the electronic behavior of the interfaces can differ from the behavior of the bulk. Reports on magnetism and superconductivity in oxide 2DEGs illustrate their capability to encompass phenomena not shown by interfaces in conventional semiconductors. This article reviews the status and prospects of oxide 2DEGs.
Tribology in Full View
Authors: Marks Laurence D. , Warren Oden L. , Minor Andrew M. , Merkle Arno P. 
Published: February 2011

AbstractFor many years, a fundamental problem in contact mechanics, both tribology and indentation problems, has been the inability to see what is taking place—the buried-interface problem. Over the past few years, there have been developments whereby it has become possible to perform contact mechanics experimentsin situwithin a transmission electron microscope. These new experiments have been enabled by both the miniaturization of sensors and actuators and improvements in their mechanical stability and force sensitivity. New information is now becoming available about the nanoscale processes of sliding, wear, and tribochemical reactions, as well as microstructural evolution during nanoindentation such as dislocation bursts and phase transformations. This article provides an overview of some of these developments, in terms of both the advances in technical instrumentation and some of the novel scientific insights.
Visualizing the Behavior of Dislocations—Seeing is Believing
Authors: Robertson Ian M. , Ferreira Paulo J. , Dehm Gerhard , Hull Robert , Stach Eric A. 
Published: February 2011

AbstractThe spatial resolution of the transmission electron microscope makes it an ideal environment in which to continuously track the real-time response of a system to an external stimulus and to discover and quantify the rate-limiting fundamental microscopic processes and mechanisms governing the macroscopic properties. Advances in instrumentation, stage design, recording media, computational power, and image manipulation software are providing new opportunities for not only observing the microscopic mechanisms but also measuring concurrently the macroscopic response. In this article, the capability of this technique as applied to mechanical properties of materials is highlighted.
Gel Sensors and Actuators
Authors: Calvert Paul 
Published: February 2011

AbstractGels, soft polymeric or composite materials that have a high fraction of water, are often found as structural materials and actuators in nature but have so far not found many uses when fabricated synthetically. We first examine some natural systems such as jellyfish, sea anemones, starfish, legumes, and human tissue, all having interesting ways of moving or otherwise reacting to the surrounding environment. Then we discuss swelling and cross-linking of hydrogels, followed by a look at actuation by electrically, thermally, and chemically stimulated gels, noting that electrical stimulation needs a chemical intermediary to show substantial actuation (comparable to human muscle, for instance). Electroactive gels have great potential as sensors and actuators but their actual uses are mainly restricted to passive drug delivery and matrices for sensors. For most applications as artificial muscles, electrically driven actuators are too weak, but chemically driven actuators look very promising. Better ways of coupling electrical energy to chemically driven gels are needed.
Materials Challenges in Present and Future Wind Energy
Authors: Hayman Brian , Wedel-Heinen Jakob , Brøndsted Povl 
Published: February 2011

AbstractThe main concept currently in use in wind energy involves horizontal-axis wind turbines with blades of fiber composite materials. This turbine concept is expected to remain as the major provider of wind power in the foreseeable future. However, turbine sizes are increasing, and installation offshore means that wind turbines will be exposed to more demanding environmental conditions. Many challenges are posed by the use of fiber composites in increasingly large blades and increasingly hostile environments. Among these are achieving adequate stiffness to prevent excessive blade deflection, preventing buckling failure, ensuring adequate fatigue life under variable wind loading combined with gravitational loading, and minimizing the occurrence and consequences of production defects. A major challenge is to develop cost-effective ways to ensure that production defects do not cause unacceptable reductions in equipment strength and lifetime, given that inspection of large wind power structures is often problematic.
Bioenergy Research Needs for Heat, Electricity, and Liquid Fuels
Authors: Farrell Alexander E. , Gopal Anand R. 
Published: February 2011

AbstractBiomass remains a key energy source for several billion people living in developing countries, and the production of liquid biofuels for transportation is growing rapidly. However, both traditional biomass energy and crop-based biofuels technologies have negative environmental and social impacts. The overall research challenge for bioenergy is to develop the technologies to produce useful products at low costs while minimizing the use of scarce resources such as arable land and water. This requires substantial advancements in modern biomass power generation and the success of liquid biofuel technologies that permit the use of lignocellulosic feedstocks or possibly algae. With such technologies, biomass resources could meet a significant fraction (over 10%) of global energy demand. Both improved policies and technologies are needed to ensure that bioenergy contributes significantly to economic, social, and environmental goals.
Hydropower, Geothermal, and Ocean Energy
Authors: Sims Ralph E.H. 
Published: February 2011

AbstractSome forms of renewable energy have long contributed to electricity generation, whereas others are just emerging. For example, large-scale hydropower is a mature technology generating about 16% of global electricity, and many smaller scale systems are also being installed worldwide. Future opportunities to improve the technology are limited but include upgrading of existing plants to gain greater performance efficiencies and reduced maintenance. Geothermal energy, widely used for power generation and direct heat applications, is also mature, but new technologies could improve plant designs, extend their lifetimes, and improve reliability. By contrast, ocean energy is an emerging renewable energy technology. Design, development, and testing of a myriad of devices remain mainly in the research and development stage, with many opportunities for materials science to improve design and performance, reduce costly maintenance procedures, and extend plant operating lifetimes under the harsh marine environment.
The Electric Power Grid: Today and Tomorrow
Authors: Amin Massoud , Stringer John 
Published: February 2011

AbstractIn the coming decades, electricity's share of total global energy is expected to continue to grow, I and more intelligent processes will be introduced into the electric power delivery (transmission and distribution) networks. It is envisioned that the electric power grid will move from an electromechanically controlled system to an electronically controlled network in the next two decades. A key challenge is how to redesign, retrofit, and upgrade the existing electromechanically controlled system into a smart self-healing grid that is driven by a well-designed market approach. Revolutionary developments in both information technology and materials science and engineering promise significant improvements in the security, reliability, efficiency, and cost effectiveness of electric power delivery systems. Focus areas in materials and devices include sensors, smart materials and structures, microfabrication, nanotechnology, advanced materials, and smart devices.
The Hydrogen Fuel Alternative
Authors: Crabtree G.W. , Dresselhaus M.S. 
Published: February 2011

AbstractThe cleanliness of hydrogen and the efficiency of fuel cells taken together offer an appealing alternative to fossil fuels. Implementing hydrogen-powered fuel cells on a significant scale, however, requires major advances in hydrogen production, storage, and use. Splitting water renewably offers the most plentiful and climate-friendly source of hydrogen and can be achieved through electrolytic, photochemical, or biological means. Whereas presently available hydride compounds cannot easily satisfy the competing requirements for on-board storage of hydrogen for transportation, nanoscience offers promising new approaches to this challenge. Fuel cells offer potentially efficient production of electricity for transportation and grid distribution, if cost and performance challenges of components can be overcome. Hydrogen offers a variety of routes for achieving a transition to a mix of renewable fuels.
Catalysts for Emerging Energy Applications
Authors: Gates Bruce C. , Huber George W. , Marshall Christopher L. , Ross Phillip N. , Siirola Jeffrey , Wang Yong 
Published: February 2011

AbstractCatalysis is the essential technology for chemical transformation, including production of fuels from the fossil resources petroleum, natural gas, and coal. Typical catalysts for these conversions are robust porous solids incorporating metals, metal oxides, and/or metal sulfides. As efforts are stepping up to replace fossil fuels with biomass, new catalysts for the conversion of the components of biomass will be needed. Although the catalysts for biomass conversion might be substantially different from those used in the conversion of fossil feedstocks, the latter catalysts are a starting point in today's research. Major challenges lie ahead in the discovery of efficient biomass conversion catalysts, as well as in the discovery of catalysts for conversion of CO2and possibly water into liquid fuels.
Increasing Building Energy Efficiency Through Advances in Materials
Authors: Judkoff Ron 
Published: February 2011

AbstractMaterials advances could help to reduce the energy and environmental impacts of buildings. Globally, buildings use about 20% of primary energy and account for 20% of atmospheric emissions. Building energy consumption emanates from a variety of sources, some of which are related to the building envelope or fabric, some to the equipment in the building, and some to both. Opportunities for reducing energy use in buildings through innovative materials are therefore numerous, but there is no one system, component, or material whose improvement alone can solve the building energy problem. Many of the loads in a building are interactive, and this complicates cost/benefit analysis for new materials, components, and systems. Moreover, components and materials for buildings must meet stringent durability and cost/performance criteria to last the long service lifetimes of buildings and compete successfully in the marketplace.
Membranes in Desalination and Water Treatment
Authors: Vainrot Nataly , Eisen Moris S. , Semiat Raphael 
Published: February 2011

AbstractMembrane techniques for water treatment have been growing significantly for the last decade. Reverse osmosis, for example, is the leading seawater desalination technique. Nanofiltration membranes are used more and more for hardness removal and even to desalinate slightly polluted waters. Ultrafiltration and microfiltration membranes are used extensively mainly as membrane bioreactors in wastewater recovery. While this trend is growing, the membranes still may be improved significantly, based on new materials designed to increase the flux of water through the membranes at reduced pressures while maintaining or even improving the rejection of dissolved matter or suspended matter. Better membranes will reduce energy consumption while maintaining affordable separation properties.
Reducing Industrial Energy Use and CO2 Emissions: The Role of Materials Science
Authors: Gielen Dolf , Newman John , Patel Martin K. 
Published: February 2011

AbstractNearly one-third of the world's energy consumption and 36% of its carbon dioxide (CO2) emissions are attributable to manufacturing industries. However, the adoption of advanced technologies already in commercial use could provide technical energy savings in industry of 27–41 exajoules (EJ), along with a reduction in CO2 emissions of 2.2–3.2 gigatonnes (Gt) per year, about 7–12% of today's global CO2 emissions. Even more significant savings can be attained on the supply side if fuel switching and CO2 capture and storage are considered. However, such changes must start in the coming decade to have a substantial impact by 2050.