bluuebunny/crossref_metadata_2025 huggingface dataset:
Drilling Technology for Deep and HPHT Containing Sour Gas well in the ChuanDongBei Field of China
Authors: LI Rong  , Wang Xi  , Shi Lin  , Xin Junhe  , Liu Lieqiang  , Duan Dexiang
Published: August 2016

ChuanDongBei Field of Sichuan Basin is a HPHT deep gas reservoir with multiple pressure systems, with maximum formation temperature up to 156 oC and pressure gradient of 1.86 at the depth of 6500m. Part of the well section contains more than 5% CO2 and near to 10% H2S, so drilling operation is extremely challenged. Firstly, this paper introduces drilling challenges such as lost circulation, severe caving-in, pipe sticking in upper section, sour gas corrosion problems, low penetration rate in the middle and deep section.
Secondly, a lot of available key drilling technologies are innovated and provided, including casing program optimization, air and nitrogen drilling to improve ROP, combination drilling with anti-HT motor and fit for purpose PDC bits, anti-HT mud along with losses prevention technologies such as MPD, anti-gas channeling and big temperature difference cementing slurry in the long interval, BOP and H2S sour gas monitoring system with emergency plan and some management advices for deep HTHP containing sour gas wells.
Finally, some unexpectable application results regarding these techniques to solve a series of drilling difficulties have been mentioned according to 40 wells cases. Take well LG01-XY as an example, which was improved average ROP to 6.4m/h, extended the footage to 1713m in one specialized bit with air hammer, reduced drilling period to 145days, reached â€œzero pollution, zero harm, zero accidentâ€ achievement during H2S interval, got premium cementing result and well bore qualify. So it could be used as a technical reference while drilling in deep HTHP containing sour gas wells in similar geologically complicated gas fields.
Smartphone addiction proneness in relation to sleep and morningness–eveningness in German adolescents
Authors: Randler Christoph , Wolfgang Lucia , Matt Katharina , Demirhan Eda , Horzum Mehmet Barış , Beşoluk Şenol
Published: August 2016

Background

Mobile phones are an important part of adolescents’ life. In this study, the relationships among smartphone addiction, age, gender, and chronotype of German adolescents were examined.

Materials and methods

Two studies focused on two different measures of smartphone addiction. The Smartphone Addiction Proneness Scale (SAPS) was applied to 342 younger adolescents (13.39 ± 1.77; 176 boys, 165 girls, and 1 not indicated) in Study 1 and the Smartphone Addiction Scale was applied to 208 older adolescents (17.07 ± 4.28; 146 girls and 62 boys) in Study 2, both samples in southwest Germany. In addition, a demographic questionnaire and the Composite Scale of Morningness (CSM) and sleep measures were implemented.

Results

The most remarkable result of this study was that morningness–eveningness (as measured by CSM scores) is an important predictor for smartphone addiction; even stronger than sleep duration. Evening oriented adolescents scored higher on both smartphone addiction scales. In addition, gender is an important predictor for smartphone addiction and girls are more prone to become addicted. In addition, while sleep duration on weekdays negatively predicted SAPS, age, sleep duration on weekends, and midpoint of sleep on weekdays and weekends did not predicted smartphone addiction in both scales. The analysis of covariance revealed statistically significant effects of the covariates gender and age in both studies, as well as the main effect of chronotype. According to the t-test results, girls had higher scores than boys in smartphone addiction.

Conclusion

Evening types and girls are more prone to become smartphone addicted.
From Dynamics to Devices: Directed Self-Assembly of Colloidal Materials
Authors: Grier David G.
Published: August 2016

Colloidal suspensions have been part of the repertoire of human industry since Paleolithic artists first dispersed pulverized minerals in rendered animal fat to make paint. Remarkably, colloidal suspensions' primary industrial applications have changed little in the 20 or 30 millennia since. People use colloidal suspensions to disperse materials into fluid media without dissolving them. Familiar examples include surface coatings such as paints and inks, and slurries used for paper making and powder transport. Dividing the material finely enough to disperse it sometimes instills the resulting particles with novel properties. Ancient Romans took advantage of quantum confinement effects in metallic and semiconductor nanoclusters to color glass—research on the mechanisms and applications of nanoclusters' properties is ongoing. In all of these cases, the dispersed material is the important agent; colloidal dispersal simply facilitates its exploitation. More recently, colloidal particles have been deliberately used to modify the rheological properties of their carrier fluids. For these applications, the material from which the colloidal particles are made is less important than how their dispersal influences the medium.

This issue of MRS Bulletin focuses on a new class of applications for colloidal suspensions stemming from some particles' innate ability to organize themselves into beautifully ordered arrays. These colloidal crystals acquire interesting and useful properties not only from their constituent materials but also from the spontaneous emergence of mesoscopic
order that characterizes their internal structure.
Nanocrystalline Silicon for Optoelectronic Applications
Authors: Tsybeskov Leonid
Published: August 2016

Light emission in silicon has been intensively investigated since the 1950s when crystalline silicon (c-Si) was recognized as the dominant material in microelectronics. Silicon is an indirect-bandgap semiconductor and momentum conservation requires phonon assistance in radiative electron-hole recombination (Figure 1a, top left). Because phonons carry a momentum and an energy, the typical signature of phonon-assisted recombination is several peaks in the photoluminescence (PL) spectra at low temperature. These PL peaks are called “phonon replicas.” High-purity c-Si PL is caused by free-exciton self-annihilation with the exciton binding energy of ~11 meV. The TO-phonon contribution in conservation processes is most significant, and the main PL peak (~1.1 eV) is shifted from the bandgap value (~1.17 eV) by ~70 meV—that is, the exciton binding energy plus TO-phonon energy (Figure 1a).
Advanced Column-IV Epitaxial Materials for Silicon-Based Optoelectronics
Authors: Sturm James C.
Published: August 2016

Over the past decade or so, research in silicon-based heterostructures has evolved from a few seminal publications on the growth and physical properties of Si1−xGex heteroepitaxial layers to a technology currently entering large-scale commercial production for heterojunction bipolar transistors (HBTs). During this period, extensive work has taken place on the optoelectronic applications of Si/Si1−x Gex such as 1.3–1.55 μam detectors for optical communication, 2–12-μm infrared detectors for two-dimensional (2D) focal plane arrays for night vision and thermal imaging, and infrared emitters for chip-to-chip optical communication as well as waveguiding and modulators. The overall goal of this work has been to merge optoelectronic functionality with the very large-scale-integration and electronic signal processing capabilities of silicon to create a silicon-based “superchip.”
How Third-Body Processes Affect Friction and Wear
Authors: Singer Irwin L.
Published: August 2016

Materials designed for rolling or sliding contact, like corrosion-resistant materials, can provide great cost savings to industry. So why can't such “tribomaterials” be designed based on materials properties that control friction and wear? In recent years, it has become clear that the properties we need to understand are not only those of the starting materials—whether bulk solids or engineered surfaces—but also those of the materials generated within the sliding (or rolling) contact, the so-called “third-body” materials. This article reviews third-body processes and their role in controlling friction and wear of practical surface treatments.

It may seem odd that properties like slipperiness and wear resistance can be easily described but are not scientifically understood. We can feel that polytetrafluoroethylene is slippery but know that it is not very wear-resistant because we can scratch it with a fork. We can sense low friction when we rub talcum powder between our fingers but know it cannot lubricate indefinitely because it gets ejected as we rub. Is it contradictory to ask for materials that are both slippery and wear-resistant? Slipperiness is associated with low shear strength whereas wear resistance is modeled on high hardness—that is, high shear strength. Before we can answer this seeming contradiction, it is useful to review some aspects of friction and wear.

More than 50 years ago, Bowden and Tabor explained how a low shearstrength film can reduce the friction coefficient between two higher shearstrength materials in sliding contact.
ER Fluids Based on Liquid-Crystalline Polymers
Authors: Inoue Akio , Ide Yohichiro , Maniwa Syunji , Yamada Hiroyuki , Oda Hiroji
Published: August 2016

Electrorheological (ER) fluids are most broadly classified as either particle dispersion or homogeneous types. The history of their development has been one of a search for fluids of either type that exhibit a large ER effect—an increase in viscosity or shear stress upon exposure to an electric field—together with longterm stability under various temperatures and conditions of use.

The first particle dispersion ER fluids were invented by W.M. Winslow in the late 1940s. Many fluids of this type have been investigated since then, and a few have been developed and adopted for practical applications.

Homogeneous ER fluids have been investigated even longer. The earliest reported observations of the ER effect were for homogeneous fluids composed of glycerin and paraffin oil in the 1890s. In the 1930s, the ER effect was also observed in polar liquids such as nitrobenzene and anirin and in colloids of superfine metal powders. In all cases however the viscosity in the electric field was only two or three times the zero-field viscosity, which is too small for useful applications.

Since the advent of low-molecular-weight liquid-crystalline (LC) materials in the 1960s, investigations have been made on the viscosity changes accompanying their inherent tendency to align in an electric field, but their maximum viscosity generally is only a few times their zero-field viscosity, and their shear stress is in any case small.
Permanent Photoinduced Refractive-Index Changes for Bragg Gratings in Silicate Glass Waveguides and Fibers
Authors: Albert Jacques
Published: August 2016

In 1978 Kenneth Hill of the Communications Research Centre in Ottawa discovered that intense blue light propagating inside the core of a germanium-doped silicate glass fiber modified the core refractive index sufficiently to form a measurable permanent hologram. Because germanium-doped silica is the material of choice for the core of most optical fiber in use today for optical communications, this “photosensitive” phenomenon has been recognized as having tremendous practical importance. Fiber Bragg gratings in particular form excellent narrow-band optical filters with a multitude of applications: sensors, fiber laser mirrors, wavelength multiplexers (the acronym for wavelength multiplexing and demultiplexing in systems is WDM), and dispersion control devices—to name a few that are already commercially available. The importance of this field can be verified in just about any current issue of journals related to lightwave technology and applications of optics. Fiber Bragg gratings are mentioned everywhere. In fact a recent issue of the Journal of Lightwave Technology is entirely devoted to this topic (and to poling of silica, a field reviewed by W. Margulis in this issue).
Acoustic Microscopy for Imaging and Characterization
Authors: Briggs Andrew , Kolosov Oleg
Published: August 2016

Acoustic microscopy is useful for characterizing with high spatial resolution the elastic structure and properties of an object. A range of techniques is now available for doing this, which enables the user to select the method and instrument that is most appropriate for a particular requirement. For imaging the interior of structures such as electronic-component packaging, an acoustic microscope operating at a relatively modest frequency can provide advanced nondestructive testing. For characterizing surface coatings and layers that may be only a fraction of a micrometer thick, higher frequency quantitative techniques are needed. For a given application, three questions should be asked at the outset: (1) What depth of material do I wish to include in my inspection? (2) Do I wish to image structures and/or defects, or do I wish to characterize elastic properties? (3) What is the minimum size of a defect or inhomogeneity that I wish to resolve or characterize (at a given depth) during my inspection? Selection of the appropriate technique will depend on the answers.
The Science of Art
Authors: Mayer James , Ainsworth Maryan
Published: August 2016

The beauty of art is the result of complex intuitive and cognitive choices made by the artist. Understanding the genesis of these choices can be as illusive as the resulting imagery, but great art seems to initiate in us a curiosity about the ideas, methods, and materials used by the creators. Connoisseurship in this century has been enriched by the application of scientific-analysis methods. The results of these investigations into the physical properties of art have shed new light on their authenticity and individual histories as well as on the craft in general. Developments in the fields of physics and chemistry have allowed us to understand more about how we perceive and interact with works of art. The articles in this issue of MRS Bulletin describe the choices made by the artist and the techniques used to analyze works of art ranging from cave paintings to pastels on paper.

This issue of the Bulletin had its genesis in an interdisciplinary course at Cornell University, “Art, Isotopes, and Analysis.” Stan Taft and James Mayer taught the course with guest lectures by Maryan Ainsworth, Richard Newman, and Dusan Stulik. Michel Menu, Debora Mayer, Dusan Stulik, Richard Newman, and Arleyn Simon have carried on the guest-lecture tradition at Arizona State University (ASU). They also participated in a symposium, “Revelations Beneath the Surface: The Science of Art,” held June 14, 1996 at ASU. The photograph (Figure 1) shows the symposium speakers.
GaN and Related Materials for Device Applications
Authors: Pearton Stephen J. , Kuo Chihping
Published: August 2016

The addition of GaN, A1N, InN, and related alloys to the family of device-quality semiconductors has opened up new opportunities in short-wavelength (visible and ultraviolet [uv]) photonic devices for display and data-storage applications, solar-blind uv detectors, and high-temperature/high-power electronics. Silicon will of course continue to dominate in microelectronics applications, and InP and GaAs and their related alloys will be the mainstays of long-wavelength lightwave communication systems and red, orange, and yellow light-emitting-diode (LED) technology, respectively. There are however many existing and emerging uses for wide-bandgap semiconductors with good electrical and optical characteristics. The purpose of this issue of MRS Bulletin is to furnish a background and summary on the exciting new developments involving GaN and related materials.

Strong efforts on the synthesis and device aspects of GaN took place in the 1960s and 1970s because of the potential for realization of blue lasers and LEDs that would extend the existing wavelength range of photonic devices. Progress was hampered because of several severe materials problems. First there was no bulk crystal growth technology for producing substrates, and epitaxial material was grown on highly lattice-mismatched substrates such as sapphire. This heteroepitaxial material was invariably highly conducting because of residual shallow donor defects or impurities. These high n-type backgrounds, combined with the relatively deep ionization levels of all of the common p-type dopant impurities, prevented the achievement of p-type doping and therefore of bipolar or injection devices.
Radio-Frequency Power Transistors Based on 6H- and 4H-SiC
Authors: Moore Karen , Trew Robert J.
Published: August 2016

In recent years, SiC has received a great deal of attention as a nearly ideal material for the fabrication of high-speed, high-power transistors. The high electric breakdown field of 3.8 × 106 V/cm, high saturated electron drift velocity of 2 × 107 cm/s, and high thermal conductivity of 4.9 W/cm K indicate SiC's potential for high-power, high-frequency operation. A wide bandgap should also allow SiC field-effect transistors (FETs) to have high radio-frequency (rf) output power at high temperatures.

These material qualities have been verified through outstanding device performance. Recent results for SiC metal-semiconductor field-effect transistors (MESFETs) have included superior frequency and power performance, with power gain at frequencies as high as 40 GHz and power densities as high as 3.3 W/mm. This represents significantly higher operating frequencies and power densities than current Si rf power FET technology, and nearly three times the power density of GaAs MESFETs, which are currently used in many commercial rf power applications. Similarly, SiC static induction transistors (SITs) have much higher power densities than their Si counterparts and have recently been demonstrated in modules with as much as 470-W total pulsed output power. This article describes microwave device operation, discusses material properties needed for rf power generation, and summarizes state-of-the-art SiC high-frequency device performance. Emphasis is placed on MESFETs and SITs since they are currently the most mature SiC-based device technologies.
Radiation Effects in Graphite and Carbon-Based Materials
Authors: Burchell T.D.
Published: August 2016

Displacement damage in graphite and carbon-based materials can occur when energetic particles, such as neutrons, ions, or electrons impinge on the crystal lattice. The displacement of carbon atoms from their equilibrium positions results in lattice strain, bulk dimensional change, and profound changes in physical properties. This article will discuss the effects of displacement damage in graphites and carbon-based materials. The materials considered here are those whose bonding is sp2—that is, graphites, pyrolytic carbons and graphites, carbon fibers, and carbon-carbon (C/C) composites. Radiation damage in sp3 (diamond) carbon forms is not discussed.

Carbon-based materials and graphites are widely used in nuclear applications. For example, polygranular (manufactured) graphites have been employed as a moderator in nuclear reactors since the 1940s. More recently, pyrolytic graphites, artificial graphites, and C/C composites have been adopted as plasma-facing components in fusion devices. Engineering applications, such as those just cited, have necessitated a full understanding of the basic mechanisms of radiation damage, as well as the effects of radiation damage on the physical properties of carbon-based materials.
Bandgap Anomaly, Atomic Ordering, and Their Applications
Authors: Suzuki Tohru
Published: August 2016

In 1916 a group of Russian chemists—Kurnakov and his colleagues—discovered that slowly cooled CuxAu1 − xmetal alloys had anomalously low electrical resistivities at simple compositions of CuAu and Cu3Au. Nine years later in 1925, Swedish physicists Johansson and Linde found by x-ray-diffraction experiments that the alloys had ordered structures on the face-centered-cubic lattice, now called CuAu I-type and AuCu3-type. Two years later, Johansson and Linde discovered CuPt-type ordering in Cu0.5Pt0.5 alloy by noticing a similar anomaly in their electrical-resistivity measurements for CuxPt1 − x. These were among the events at the dawn of physical metallurgy and study on order-disorder transformations. Many years later in 1985, the first observation of ordering in semiconductor alloys was made in AlGaAs grown on GaAs(110); the type was CuAu I. CuPt-type ordering was observed in SiGe grown on Si(001). Since the (110) orientation of the substrate for AlGaAs was clumsy for practical purposes and the degree of ordering in SiGe was extremely low, these phenomena seemed to have little relevance in practical applications. Other observations were made such as famatinite-type ordering in GalnAs and chalcopyrite-type ordering in GaAsSb. These observations however were quite rare, with only isolated cases reported.
Defects in Polymer Crystals
Authors: Wunderlich Bernhard , Kreitmeier Stefan N.
Published: August 2016

The development of early knowledge about crystals of flexible macromolecules (usually called simply “polymers”) and their defects was reviewed in Reference. Much of the initial research followed the information gathered on crystals of small molecules, metals, salts, and ceramics. Very quickly, however, the special nature of polymers became obvious. It was suggested some time ago to describe semicrystalline polymers with the help of zero- to three-dimensional defects. The present status of this scheme is summarized in this article.

Crystallized polymers are rarely in equilibrium. Therefore, the phase rule, which permits the presence of only one phase with two degrees of freedom (temperature and pressure) for a onecomponent material, does not apply. This nonequilibrium state is kept metastable by restrictions caused by the molecules that cross the interfaces (two-dimensional defects). The strain propagated to the noncrystalline areas produces three-dimensional defects of limited mobility. The overall structure can also be described as being microphase-separated.

Often the sizes of the different phases can be as small as the nanometer scale. One-dimensional or line defects, also called dislocations, became obvious in polymers with the first observations of solution-grown crystals of polyethylene that showed frequent growth spirals. Because of the molecular chain struc ture, many of these dislocations are sessile (immobile) and cannot participate for example, in deformation mecha nisms. Until recently, zero-dimensiona or point defects were understood largely because of molecular-mechanics calculations.
Chain-End Defects in Extended-Chain Polymer Solids
Authors: Martin David C. , Wilson Patricia M. , Liao Jun , Jones Marie-Christine G.
Published: August 2016

Understanding the influence of local variations in symmetry (“defects”) on the macroscopic properties of polymers in the condensed state is an ongoing experimental and theoretical challenge. Studies of defects in solids require the most information-intensive description of microstructure since it is not possible to describe a “defect” without understanding the morphology of the majority phase as well.

The nature of defects in polymers has been discussed elsewhere, including other articles in this issue of theMRS Bulletin. The structure, properties, and mobility of defects in polymers are all profoundly influenced by the covalently bonded chain backbone. In polymers, there are unique defects such as chain folds and twists that have no obvious analogue in materials of small molar mass. Here, we examine a particular type of defect that is present in all polymer systems with finite molecular weight: chain ends. Our interest will focus on chain ends in polymers that are essentially fully extended parallel to a certain preferred orientation axis.

The extended-chain microstructure was originally envisioned by Staudinger as a “continuous crystal” in which high-molecular-weight polymers would be perfectly oriented and close-packed together laterally. Extended-chain polymer fibers such as poly(paraphenylene terephthalamide) (PPTA or Kevlar®), gelspun polyethylene (Spectra®), and the rigid-rod polymers poly(paraphenylene benzobisthiazole) (PBZT) and poly(paraphenylene benzobisoxazole (PBZO or PBO) (Structure 1) closely approach this conceptual limit. The outstanding tensile moduli (100–400 GPa) and tensile strengths (2–4 GPa or higher) of these fibers have generated considerable interest for lightweight structural applications. Extendedchain polymers can also be prepared by solid-state polymerizations of appropriate monomer precursors. Perhaps the most familiar of this latter class of materials are the polydi-acetylenes, first developed by Wegner.
Polymer Surfaces and Interfaces
Authors: Koberstein J.T.
Published: August 2016

Since their commercialization in the late 1940s, applications for synthetic polymers have grown at an extraordinary rate, to the point where polymers are now ubiquitous in our society. The demands placed upon polymer performance have paralleled the growth in applications and has driven the development of sophisticated multiconstituent polymer formulations with many outstanding physical and mechanical properties. Many applications require that a polymeric material be attached to or in contact with another material. In some cases, such as the classic nonstick fry pan, as well as lubrication and release paper, it is desirable to create surfaces that do not interact with the material in contact. On the other hand, in applications such as rubber toughening of blends, filled or fiber-reinforced polymers, and coatings, dissimilar materials must adhere to each other if high performance is to be obtained. While the majority of the research and development efforts to date have centered on optimizing bulk properties, the focus is now shifting toward the development of polymer systems with controlled surface and interfacial properties.

The recent flurry of activity in polymer interfacial science can be traced to the simultaneous emergence of three factors: a strong commercial need to control the surface properties of advanced multicomponent polymer systems, the availability of sophisticated theoretical methods for studying polymer surface and interphase problems, and the devel opment of new characterization techniques capable of investigating molecular level structure at polymer interphases. The seven articles that comprise this issue provide an overview of basic polymer interface science by discussing some of the current advances in polymer interface theory, by presenting many of the new techniques available for polymer interphase characterization, and by illustrating some of the interesting and challenging problems associated with their applications.
Heteroepitaxy and Strain: Applications to Electronic and Optoelectronic Materials
Authors: Schowalter Leo J.
Published: August 2016

Heteroepitaxy is an important area of materials research because of its applicability to a variety of technological applications. One area presently attracting a great deal of research is heteroepitaxy of electronic and optoelectronic materials. Here the word heteroepitaxy is emphasized to distinguish it from the much more common epitaxial growth of essentially the same material where only variations in the concentration of dopants is allowed. When materials scientists and engineers from the electronics industry refer to heteroepitaxy, they mean the oriented-crystal growth of some interesting (at least, to them!) material on a single-crystal substrate of some other material. By using heteroepitaxy, it is possible to tailor the electronic or optical properties in a way that is just not possible with doped, epitaxial growth of the same material. There are some rare examples of pairs of materials that have the same crystal structure, are very closely lattice-matched, and are dissimilar enough in their optical and/or electronic properties to make heteroepitaxy interesting. One such couple, AlxGa1−xAs/GaAs (lattice mismatch of 0.1% when x = 1), has been extensively exploited over the last 30 years.
The Effect of Strain on the Formation of Dislocations at the SiGe/Si Interface
Authors: LeGoues F.K.
Published: August 2016

Recently much interest has been devoted to Si-based heteroepitaxy, and in particular, to the SiGe/Si system. This is mostly for economical reasons: Si-based technology is much more advanced, is widely available, and is cheaper than GaAs-based technology. SiGe opens the door to the exciting (and lucrative) area of Si-based high-performance devices, although optical applications are still limited to GaAs-based technology. Strained SiGe layers form the base of heterojunction bipolar transistors (HBTs), which are currently used in commercial high-speed analogue applications. They promise to be low-cost compared to their GaAs counterparts and give comparable performance in the 2-20-GHz regime. More recently we have started to investigate the use of relaxed SiGe layers, which opens the door to a wider range of application and to the use of SiGe in complementary metal oxide semiconductor (CMOS) devices, which comprise strained Si and SiGe layers. Some recent successes include record-breaking low-temperature electron mobility in modulation-doped layers where the mobility was found to be up to 50 times better than standard Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Even more recently, SiGe-basedp-type MOSFETS were built with oscillation frequency of up to 50 GHz, which is a new record, in anyp-type material for the same design rule.
Intense Ion-Beam Treatment of Materials
Authors: Davis Harold A. , Remnev Gennady E. , Stinnett Regan W. , Yatsui Kiyoshi
Published: August 2016

Over the past decade, researchers in Japan, Russia, and the United States have been investigating the application of intense-pulsed-ion-beam (IPIB) technology (which has roots in inertial confinement fusion programs) to the surface treatment and coating of materials. The short range (0.1–10 μm) and high-energy density (1–50 J/cm2) of these short-pulsed (t ≥ 1 μs) beams (with ion currents I = 5–50 kA, and energies E = 100–1,000 keV) make them ideal flash-heat sources to rapidly vaporize or melt the near-surface layer of targets similar to the more familiar pulsed laser deposition (PLD) or laser surface treatment. The vaporized material can form coatings on substrates, and surface melting followed by rapid cooling (109 K/s) can form amorphous layers, dissolve precipitates, and form nonequilibrium microstructures.

An advantage of this approach over laser processing is that these beams deliver 0.1–10 KJ per pulse to targets at expected overall electrical efficiencies (i.e., the ratio of extracted ion-beam energy to the total energy consumed in generating the beam) of 15–40% (compared to < 1% for the excimer lasers often used for similar applications). Consequently IPIB hardware can be compact and require relatively low capital investment. This opens the promise of environmentally conscious, low-cost, high-throughput manufacturing. Further, efficient beam transport to the target and excellent coupling of incident ion energy to targets are achieved, as opposed to lasers that may have limited coupling to reflective materials or produce reflecting plasmas at high incident fluence. The ion range is adjustable through selection of the ion species and kinetic energy, and the beam energy density can be tailored through control of the beam footprint at the target to melt (1–10 J/cm2) or to vaporize (10–50 J/cm2) the target surface. Beam pulse durations are short (≥ 1 μs) to minimize thermal conduction. Some disadvantages of IPIB processing over laser processing include the need to form and propagate the beams in vacuum, and the need for shielding of x-rays produced by relatively low-level electron current present in IPIB accelerators. Also these beams cannot be as tightly focused onto targets as lasers, making them unsuitable for applications requiring treatment on small spatial scales.
Crystalline Si Films for Integrated Active-Matrix Liquid-Crystal Displays
Authors: Im James S. , Sposili Robert S.
Published: August 2016

The fabrication of thin-film-transistor (TFT) devices on a transparent substrate lies at the heart of active-matrix-liquid-crystal-display (AMLCD) technology. This is both good and bad. On one hand it is a difficult task to manufacture millions of intricate semiconductor devices reliably over such large display substrates. On the positive side, AMLCD technology can aspire to become much more than a “display” technology. The idea is as follows: It is possible for one to readily fabricate additional transistors to execute various electronic functions—those that would otherwise be handled by separate large-scale-integration (LSI) and very large-scale-integration (VLSI) circuits—on the periphery of the display. Since this can be done, in principle, with no—or a minimal number of—additional processing steps, substantial cost reduction is possible and significant value can be added to the final product.

Doing so and doing it well can ultimately lead to “system-on-glass” products in which the entire electronic circuitry needed for a product is incorporated directly onto a glass substrate. This means that integrated active-matrix liquid-crystal displays (IAMLCDs) have the potential to bypass conventional Si-wafer-based products and may lead TFT technology to compete directly against Si-wafer-based monolithic integrated circuits.
Diamond-Based Field-Emission Displays
Authors: Jaskie James E.
Published: August 2016

Diamond has existed in the natural state for thousands of years. It was mainly used as a jewel for its optical brilliance and for its hardness. In the 1950s methods were developed to fabricate synthetic diamonds commercially. This greatly increased diamond's industrial use, mostly for grinding and lapping applications. Diamond is a crystalline form of carbon, a group-IV element in the periodic table. Silicon and germanium are also Group-IV elements and also have the same crystalline lattice structure as diamond. Hence there has been theoretical interest in diamond's electronic properties since the beginning of the semiconductor age. However the cost and poor crystalline quality of both natural and synthetic diamond have precluded any real industrial interest in diamond as an electronic material. Methods of low-temperature and low-pressure diamond-film deposition, developed initially by the Russians in the 1950s and 1960s (and thence by the Japanese, and eventually by others) has made it possible to use this exotic material as an electronic substrate.

Diamond, in single-crystalline, polycrystalline, and diamondlike carbon (DLC) forms, is a material with many unusual properties. It is the hardest naturally occurring material, the most thermally conductive, and the most transparent. It also has the slickness of Teflon. In regard to many physical properties, it is at the extreme end of the scale. One of the more unusual and important properties that it possesses is its presentation of a rather small barrier to the emission of electrons into a vacuum.
Materials for Magnetic-Tape Media
Authors: Onodera Seiichi , Kondo Hirofumi , Kawana Takahiro
Published: August 2016

Magnetic recording has been responsible for the widespread and inexpensive recording of sound and video. Despite the availability of other means of storing data, such as optical recording and semiconductor devices, flexible magnetic-recording media have advantages such as (1) low cost, (2) stable storage, (3) a relatively high data rate, (4) a relatively short seek time, and (5) high-volumetric information density.

The first commercially available magnetic-recording tapes were produced in 1947 by the 3M Company. Since that time, magnetic tapes have developed rapidly for use in audio, video, and digital-data recording systems.

The linear-analogue technique is commonly used for most audio recorders. The magnetic tape is transported at a speed of several cm/s over a stationary head. On the other hand, helical-scanning rotary heads were developed for video recording, which afforded a high head-to-tape speed of more than several m/s and high recording-density capabilities. However high relative speed causes wear of the tape. The success of a tape in actual use depends critically on its tribological properties.

Magnetic media are divided into two groups: (1) particulate media where magnetic particles are dispersed in a polymer binder with some additives and coated onto the substrate and (2) thin-film media in which monolithic, magnetic thin films are deposited onto the substrate in vacuum. The overwhelming preponderance of media fabricated to date have been coated media. However continuous demand for increasingly higher recording density has led to thin-film media.
Mesoscopic Disorder
Authors: Weitz D.A.
Published: August 2016

Disorder characterizes most of the materials that surround us in nature. Despite their great technological importance, materials with ordered crystalline structures are relatively rare. Examples of disordered materials, however, abound, and their forms can be as varied as their number. The paper on which these words are printed has a disordered structure composed of a highly interconnected network of fibers. It has also been coated with particulate materials to improve its properties and the visibility of the ink. The reading glasses you may require to focus on these words are composed of a glass or polymer material that is disordered on a molecular level. Even the structure of your hand holding this magazine is disordered. These and virtually all other disordered materials are typically parameterized by a characteristic length scale. Above this length scale, the material is homogeneous and the effects of the disorder are not directly manifest; below this characteristic length the disorder of the structure dominates, directly affecting the properties.

The range of characteristic length scales for the disordered materials around us is immense. For the glass or polymer of your reading glasses, it is microscopic; the disorder is apparent only at the molecular level, while above this level the material is homogeneous. For the paper on which this magazine is printed, the scale is larger; the paper is white partly because the disordered fiber network has within it structures that are comparable in size to the wavelength of light, resulting in strong scattering of the light.
What Is Shaking in the Sandbox?
Authors: Jaeger Heinrich M. , Knight James B. , Liu Chu-heng , Nagel Sidney R.
Published: August 2016

In 1831, Faraday reported to the Royal Society of London that granular material inside a container, when vibrated, would spontaneously begin to exhibit convection rolls, similar to what is observed in normal fluids when heated from below. This observation indicated that not only can a granular material act like a fluid, but also that vibrations can affect the properties of these materials in important ways. Such phenomena are of immediate practical importance because granular materials exist all around us. We use sand and gravel to build the roads we drive on; we process grain to provide our food supply; we mine ore to provide coal, minerals, and precious commodities; we take powders and pills to cure what ails us. Many of the phenomena observed in granular media are prototypical examples of complex, nonequilibrium behavior that is also found in an increasing number of other systems. As a result, sandpiles have served as a macroscopic and visually appealing metaphor for thinking about a number of microscopic systems that are not directly accessible to our senses. Despite the common occurrence of these materials, their properties are not at all well understood and most of our knowledge centers on the subset of static, equilibrium properties of granular matter. Only over the last few years have physicists and engineers begun to unravel some of the exceptional time-dependent, nonequilibrium properties that these seemingly simple materials exhibit. This review focuses on recent developments in the newly emerging field of granular dynamics and, in particular, addresses the role of vibration in determining the phenomena observed in such media.
In Situ Observations of Misfit Dislocations in Lattice-Mismatched Epitaxial Semiconductor Heterostructures
Authors: Hull Robert , Bean John
Published: August 2016

This article describes the application of transmission electron microscopy (TEM) to real-time, in situ dynamic observations of dislocations in strained epitaxial semiconductor heterostructures. Such experiments allow us to directly observe the formation, motion, and interaction of mis-fit dislocations. Preliminary extension of this work to the in situ measurement of the electrical properties of misfit dislocations will also be described.

The Fundamental Scientific Issue

It is well established that it is possible to grow a thin, coherent epitaxial layer on a substrate with a slightly different lattice parameter, as illustrated in Figure la. This concept is known as strained layer epitaxy. In the fields of semiconductor physics and device design, strained layer epitaxy offers many exciting new opportunities (see Reference 1 for a review). A coherently strained structure, however, will store an enormous elastic strain energy density in the epitaxial layer, due to the distortion of interatomic bonds. Therefore, as the epitaxial layer increases in thickness during growth, it will become increasingly energetically favorable to relax this strain energy. A number of relaxation routes exist: (1) roughening of the epitaxial layer surface (see, for example, Reference 2); (2) interdiffusion of the layers (this will generally only be significant at temperatures which are a large fraction of the layer melting temperatures (e.g., Reference 3)); and (3) introduction of a dislocation network into the substrate/epilayer interface, which as shown schematically in Figure lb, will allow the epitaxial layer to relax toward its bulk lattice parameter. This dislocation mechanism is the most prevalent strain relaxation mechanism at typical crystal growth and processing temperatures, and we concentrate on this mechanism in our experimental studies.
Visualization of Dynamic Near-Surface Processes
Authors: Twesten Ray D. , Gibson J. Murray , Ross Frances M.
Published: August 2016

Electron microscopy has played an undeniably important role in the development and understanding of new materials. One particular method, plan-view transmission electron microscopy (TEM), has been used to reveal many aspects of materials and to help answer questions that are not accessible by other methods. In planview TEM, materials are studied either by the image contrast caused by diffraction or by direct diffraction analysis. The studies are often at a somewhat lower resolution than is possible with some other electron-based microscopies or, in the case of diffraction, must be interpreted in terms of an average effect. Nevertheless, plan-view TEM is very useful because properties at these intermediate length scales typically determine important materials characteristics. It is plan-view microscopy that gives us the big picture of what is happening in a material.

Until recently, TEM studies of materials have entailed comparing samples taken at various stages of processing and trying to observe and understand the mechanisms that determine the material behavior. With the advent of controllable specimen environments, materials processing has been taken into the TEM, allowing direct observation of the microstructural development. Here we will focus particularly on surface and near-surface processes, such as oxidation.
Photovoltaic Efficiency Measurements
Authors: Emery Keith
Published: August 2016

A variety of performance indicators have been employed by the photovoltaic (PV) community to rate the performance of PV cells, modules, and arrays. The PV power conversion efficiency under a set of standard reporting conditions serves as a basis for meaningful comparisons of PV performance, within and among PV technologies. PV efficiency is defined as 100 times the maximum PV electrical power density produced divided by the incident light power at a reference PV temperature, total irradiance, and spectral irradiance. Standard reporting conditions commonly used by the PV community are summarized in Table I.

The direct and global reference spectra were generated by a comprehensive Monte-Carlo computer model and actually integrate to 768 W m−2 and 964 W m−2. The terrestrial PV community has arbitrarily assigned a 1-sun total irradiance of 1,000 W m−2 for the global and direct reference spectra. The term “direct” in Table I refers to the direct-normal (5° field of view about the sun) component of the global spectral irradiance distribution. The term “global” in Table I refers to the spectral irradiance distribution on a 37-tilted south-facing surface with a solar zenith angle of 48.2° (AM1.5). The terms AM1 or AM1.5 are often used to refer to standard spectra, but the relative optical air mass (AM) is a geometrical quantity and can be obtained by taking the secant of the angle between the sun and the zenith.
Chemistry of Self-Assembling Bilayers and Related Molecular Layers
Authors: Kunitake Toyoki
Published: August 2016

The two-dimensional packing of organic molecules (small and large) produces ultimately thin organic films. Several possibilities exist for achieving this result from linear polymers, taking advantage of surfaces and interfaces as spatial templates. Monomolecular polymer layers can be prepared on the surface of water by polymerization of monolayers. They can be transferred onto solid supports by the Langmuir-Blodgett-Kuhn technique. Polyion complexation at the air-water interface provides a second method of two-dimensional arrangements of linear polymers. More recent approaches include polymerization-induced epitaxy (PIE) and alternate polyion adsorption. In the case of PIE, growing polymer chains in solution are adsorbed onto immersed graphite plates, most probably as single polymer layers (Figure la). Chain alignment is commensurate with the graphite lattice, as confirmed by scanning tunneling microscopy (STM). This epitaxial adsorption is independent of polymerization mechanisms. On the other hand, the alternate adsorption consists of sequential dipping of charged solid supports in aqueous solutions of oppositely charged linear polyions (Figure 1b). The regularity of the layer thickness is remarkable and, under appropriate conditions, the deposition is repeatable without limit. This method is applicable not only to pairs of linear polyions but also to combinations of linear polyions with water-soluble proteins or inorganic nanoparticles.