Synthesis of Crystalline Black Phosphorus Thin Film on Sapphire

Black phosphorus (BP) has recently attracted significant attention due to its exceptional physical properties. Currently, high‐quality few‐layer and thin‐film BP are produced primarily by mechanical exfoliation, limiting their potential in future applications. Here, the synthesis of highly crystalline thin‐film BP on 5 mm sapphire substrates by conversion from red to black phosphorus at 700 °C and 1.5 GPa is demonstrated. The synthesized ≈50 nm thick BP thin films are polycrystalline with a crystal domain size ranging from 40 to 70 µm long, as indicated by Raman mapping and infrared extinction spectroscopy. At room temperature, field‐effect mobility of the synthesized BP thin film is found to be around 160 cm² V^?1 s^?1 along armchair direction and reaches up to about 200 cm² V^?1 s^?1 at around 90 K. Moreover, red phosphorus (RP) covered by exfoliated hexagonal boron nitride (hBN) before conversion shows atomically sharp hBN/BP interface and perfectly layered BP after the conversion. This demonstration represents a critical step toward the future realization of large scale, high‐quality BP devices and circuits.     

Preparation and characterization of biocompatible carbon electrodes

Electron transfer in microbial fuel cell and biosensors could be facilitated through high conductive materials with enhanced active surface area and appropriate redox potential suited to microbial metabolism. In the first strategy based on bulk doping, graphite/epoxy composite electrode (GECE) bulk was modified with six types of metal ion which were prepared through a wet impregnation procedure. In the second strategy, immobilization of redox dye on carbon cloth and graphite sheet was carried out using N,N′-dicyclohexylcarbodiimide for surface modification. Crystallinity, morphology, surface chemistry and electrochemical properties of all modified electrodes were investigated. Influence of redox behavior of electrodes suited to microbial metabolism and conducive to biofilm formation have been examined. It was observed that the Fe³⁺ doped GECE surfaces exhibited significantly high biofilm formation of 1.10(±0.18) × 10⁷ CFU/cm² as compared to other dopants. The microbial growth on the carbon cloth electrode and carbon fiber reinforced plate were found to be less (2.6(±0.97) × 10⁴, 4.8(±1.8) × 10³ CFU/cm² respectively) compared to GECEs.     

Continuance in online participation following the compromise of older adults’ identity information: a literature review

ABSTRACT

This paper presents findings from a literature review on older adults continued use of the Internet following an identity theft incident. Globally, identity theft is increasing, statistics show that the number of older adults falling victim to identity theft is growing. Victims of identity theft suffer emotional, physical, psychological, and social problems; many change their behaviour as a result. The aim of the review was to examine literature to determine what is known regarding how older adults use the Internet and/or modify their online behaviour following an identity theft event. It was found that knowledge is lacking regarding the impact that identity theft events have on older adults’ continuation of Internet use. Little research has been undertaken to understand the factors and interrelationships that contribute to the situation. The review highlights that a systems ergonomics approach should be considered as an appropriate framework to drive future research in this area.     

Millimeter-wave antireflection coating for cryogenic silicon lenses

We have developed and tested an antireflection (AR) coating method for silicon lenses used at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR-coated flat piece is less than 1.5% at the design wavelength. The coating has been applied to flats and lenses and has survived multiple thermal cycles from 300 to 4 K. We present the manufacturing method, the material properties, the tests performed, and estimates of the loss that can be achieved in practical lenses.     

One nanometer resolution electrical probe via atomic metal filament formation

Scanning probe microscopy has been widely used to investigate various interactions in microscopic nature. Particularly, conductive atomic force microscopy (C-AFM) can provide local electronic signals conveniently, but the probe resolution of C-AFM has been limited by the tip geometry. Here, we improve the probe resolution greatly by forming an atomic-size metallic filament on a commercial C-AFM tip. We demonstrate ～1 nm lateral resolution in C-AFM using the metal filament tip. The filament tip is mechanically robust and electrically stable in repeated scans under ambient conditions since it is imbedded in a stable insulating matrix. The formation of the atomic filament is highly controllable and reproducible and can be easily integrated to existing AFM tip technologies to produce the next generation of high-resolution electrical and other scanning probes.     

Hollow carbon nanofiber-encapsulated sulfur cathodes for high specific capacity rechargeable lithium batteries

Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cycling of the cells. The hollow carbon nanofiber arrays were fabricated using anodic aluminum oxide (AAO) templates, through thermal carbonization of polystyrene. The AAO template also facilitates sulfur infusion into the hollow fibers and prevents sulfur from coating onto the exterior carbon wall. The high aspect ratio of the carbon nanofibers provides an ideal structure for trapping polysulfides, and the thin carbon wall allows rapid transport of lithium ions. The small dimension of these nanofibers provides a large surface area per unit mass for Li(2)S deposition during cycling and reduces pulverization of electrode materials due to volumetric expansion. A high specific capacity of about 730 mAh/g was observed at C/5 rate after 150 cycles of charge/discharge. The introduction of LiNO(3) additive to the electrolyte was shown to improve the Coulombic efficiency to over 99% at C/5. The results show that the hollow carbon nanofiber-encapsulated sulfur structure could be a promising cathode design for rechargeable Li/S batteries with high specific energy.     

Measuring college sailing teams ability: an application of the many-facet Rasch model to ordinal data

For those who look at typical approaches to sports ranking, sailing seems an almost impossible challenge, thereby making the evidence supporting Rasch measurement in this study even more intriguing. This article describes our application of MFRM and the results from our analysis of one year's data from the North American college sailing competitions. We discuss the following issues for inclusion in the development of a Rasch model useful to college sailing team ability: 1. The level of data quality (as described by Stevens, 1946) 2. The connectedness of the contests 3. Empty cells (missing data) 4. Interpreting outliers, trends, or unusual results 5. Judges' or polls' bias Our results indicate the utility and precision of MFRM as a tool generally appropriate for ordinal ranking applications and sailing ability specifically.     

Modeling relations between hassles and internalizing and externalizing symptoms in adolescents: A four-year prospective study.

This study examined the relations between hassles and internalizing and externalizing symptoms across 4 years in adolescents who varied with regard to their risk for psychopathology. The sample comprised 240 adolescents assessed in 6th, 7th, 8th, and 9th grades regarding their level of peer and academic hassles and internalizing and externalizing symptoms. Structural equation modeling was used to construct latent variables of hassles and internalizing and externalizing syndromes. Results varied by informant about the teens' symptoms. For adolescent report, the stress exposure model fit the data best for internalizing syndromes; that is, higher levels of stressors predicted significantly higher levels of self-reported symptoms 1 year later. For mother report of adolescents' symptoms, the stress generation model fit the data best for both internalizing and externalizing syndromes; that is, higher levels of adolescents' internalizing and externalizing symptoms, as reported by their mothers, significantly predicted higher levels of hassles 1 year later. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality traits, perceived risk, and risk-reduction behaviors: A further study of smoking and radon.

Personality traits and risk perceptions were examined as predictors of changes in smoking behavior. Participants (N = 697) were part of a randomized controlled trial of interventions to reduce exposure to the combined hazard of radon and cigarette smoke. Participants with higher perceived risk at baseline for the combination of smoking and radon were more likely to have a more restrictive household smoking ban in place at 12-month follow-up (p p p     

"Planes, trains, automobiles--and tea sets: Extremely intense interests in very young children": Correction to DeLoache, Simcock, and Macari (2007).

Reports an error in "Planes, trains, automobiles--and tea sets: Extremely intense interests in very young children" by Judy S. DeLoache, Gabrielle Simcock and Suzanne Macari (Developmental Psychology, 2007[Nov], Vol 43[6], 1579-1586). The DOI for the supplemental materials was printed incorrectly. The correct DOI is as follows: http://dx.doi.org/10.1037/0012-1649.43.6.1579.supp. (The following abstract of the original article appeared in record 2007-16709-024.) Some normally developing young children show an intense, passionate interest in a particular category of objects or activities. The present article documents the existence of extremely intense interests that emerge very early in life and establishes some of the basic parameters of the phenomenon. Surveys and interviews with 177 parents revealed that nearly one third of young children have extremely intense interests. The nature of these intense interests is described, with particular focus on their emergence, commonalities in the content of the interests, and the reactions of other people to them. One of the most striking findings is a large gender difference: Extremely intense interests are much more common for young boys than for girls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)