6,160 research outputs found

    A non-dispersive Raman D-band activated by well-ordered interlayer interactions in rotationally stacked bi-layer Graphene

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    Raman measurements on monolayer graphene folded back upon itself as an ordered but skew-stacked bilayer (i.e. with interlayer rotation) presents new mechanism for Raman scattering in sp2 carbons that arises in systems that lack coherent AB interlayer stacking. Although the parent monolayer does not exhibit a D-band, the interior of the skewed bilayer produces a strong two-peak Raman feature near 1350 cm-1; one of these peaks is non-dispersive, unlike all previously observed D-band features in sp2 carbons. Within a double-resonant model of Raman scattering, these unusual features are consistent with a skewed bilayer coupling, wherein one layer imposes a weak but well-ordered perturbation on the other. The discrete Fourier structure of the rotated interlayer interaction potential explains the unusual non-dispersive peak near 1350 cm-1

    Acoustic signatures of the seafloor: Tools for predicting grouper habitat

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    Groupers are important components of commercial and recreational fisheries. Current methods of diver-based grouper census surveys could potentially benefit from development of remotely sensed methods of seabed classification. The goal of the present study was to determine if areas of high grouper abundance have characteristic acoustic signatures. A commercial acoustic seabed mapping system, QTC View Series V, was used to survey an area near Carysfort Reef, Florida Keys. Acoustic data were clustered using QTC IMPACT software, resulting in three main acoustic classes covering 94% of the area surveyed. Diver-based data indicate that one of the acoustic classes corresponded to hard substrate and the other two represented sediment. A new measurement of seabed heterogeneity, designated acoustic variability, was also computed from the acoustic survey data in order to more fully characterize the acoustic response (i.e., the signature) of the seafloor. When compared with diver-based grouper census data, both acoustic classification and acoustic variability were significantly different at sites with and without groupers. Sites with groupers were characterized by hard bottom substrate and high acoustic variability. Thus, the acoustic signature of a site, as measured by acoustic classification or acoustic variability, is a potentially useful tool for stratifying diver sampling effort for grouper census

    1999 Oregon Winery Report

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    This statewide survey report on Oregon wineries covers crush, equivalent wine production, inventory and equivalent inventory, and sales. The report also contains some comparisons of data for 1998 and 1999. According to this report, Oregon saw the second-largest harvest in terms of tonnage of crushed grapes; additionally, cooperage capacity continued to grow

    Seams Brash

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    Seams Brash was created to permit student exploration of new sewing techniques such as pleating and beading in addition to working with a variety of body types. Inspiration was drawn from many current and historical designer collections. The goal of the line was to create functional gowns with elements of surprise and a touch of couture with the hand pleating and beading. Each dress represents a different individual with unique lines, fabric choices, silhouettes, and proportions.Faculty Sponsor: Andrea Eklund, M

    Characterisation of the VELO High Voltage System

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    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence that the high voltage system can be safely used and demonstrate that low noise is produced by the power supplies

    Clathrate Structure for Electronic and Electro-Optic Applications

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    A method including the steps of (a) depositing a metal layer on a selected portion of a silicon substrate under a first set of predetermined conditions to form an metal silicide layer and an intermediate n-type silicon layer; and (b) exposing the metal silicide layer and the n-type silicon layer to a second set of predetermined conditions to form a silicon clathrate film on the selected portion of the silicon substrate, where the intermediate n-type silicon layer acts to bond the silicon clathrate to the silicon substrate to form a silicon clathrate structure

    Self-presentation concerns may contribute towards the understanding of athletes' affect when trialling for a new sports team

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    A vignette-based experimental manipulation was used to examine the impact of self-presentation concerns on athletes’ affect and cognitive appraisal. Others’ reactions were described, so as to emphasize or de-emphasize self-presentation concerns. Athletes given cause to believe that they were generating unfavourable impressions experienced more negative affect and reported more threat-based appraisal. Athletes exposed to information de-emphasizing self-presentation concerns experienced more positive affect and reported more of a challenge-based appraisal. The findings indicate a potential opportunity (e.g., de-emphasising self-presentation concerns, providing a supportive interpersonal environment) that others (e.g., coaches and teammates) could act on to improve athlete experiences during sports trials
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