bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.