4,465 research outputs found
Morphology of Graphene on SiC(000-1) Surfaces
Graphene is formed on SiC(000-1) surfaces (the so-called C-face of the
crystal) by annealing in vacuum, with the resulting films characterized by
atomic force microscopy, Auger electron spectroscopy, scanning Auger microscopy
and Raman spectroscopy. Morphology of these films is compared with the graphene
films grown on SiC(0001) surfaces (the Si-face). Graphene forms a terraced
morphology on the C-face, whereas it forms with a flatter morphology on the
Si-face. It is argued that this difference occurs because of differing
interface structures in the two cases. For certain SiC wafers, nanocrystalline
graphite is found to form on top of the graphene.Comment: Submitted to Applied Physics Letters; 9 pages, 3 figures; corrected
the stated location of Raman G line for NCG spectrum, to 1596 cm^-
"It's cleaner, definitely": Collaborative Process in Audio Production.
Working from vague client instructions, how do audio producers collaborate to diagnose what specifically is wrong with a piece of music, where the problem is and what to do about it? This paper presents a design ethnography that uncovers some of the ways in which two music producers co-ordinate their understanding of complex representations of pieces of music while working together in a studio. Our analysis shows that audio producers constantly make judgements based on audio and visual evidence while working with complex digital tools, which can lead to ambiguity in assessments of issues. We show how multimodal conduct guides the process of work and that complex media objects are integrated as elements of interaction by the music producers. The findings provide an understanding how people currently collaborate when producing audio, to support the design of better tools and systems for collaborative audio production in the future
Dissipative and Dispersive Optomechanics in a Nanocavity Torque Sensor
Dissipative and dispersive optomechanical couplings are experimentally
observed in a photonic crystal split-beam nanocavity optimized for detecting
nanoscale sources of torque. Dissipative coupling of up to approximately
MHz/nm and dispersive coupling of GHz/nm enable measurements of sub-pg
torsional and cantilever-like mechanical resonances with a thermally-limited
torque detection sensitivity of 1.2 in ambient conditions and 1.3 in low vacuum. Interference between
optomechanical coupling mechanisms is observed to enhance detection sensitivity
and generate a mechanical-mode-dependent optomechanical wavelength response.Comment: 11 pages, 6 figure
Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy
BACKGROUND and AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients
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