196,600 research outputs found
Nonlinear fibre design for broadband phase sensitive amplification
No full textWe present a soft glass fibre design for high nonlinearity and broadband, low dis-persion and simulate its performance as a phase sensitive amplifier for high bit rate signals at 1 T b/s. We use a degenerate, two pump four wave mixing scheme and show that with a fibre length of less than 1 m we are able to achieve 14 dB discrimination between the amplified and deamplified signal quadratures with 1 W pump power.H. Tilanka Munasinghe, Shahraam Afshar V., David J. Richardson, and Tanya M. Monrohttp://www.iqec-cleopr2011.com/http://www.opticsinfobase.org/abstract.cfm?uri=CLEOPR-2011-C70
Group Emotions
No full textPre-registration of Experiment 2 (Mackie, Smith, Banerji, & Munasinghe, 2024). Project registration of Mackie et al. (2024) is at
https://osf.io/wb2eu/?view_only=b009abb21ba04c5ca2f0aaab31cc923
Seed-assisted growth of TiO2 nanowires by thermal oxidation for chemical gas sensing
No full textHerein, we report the catalyst assisted growth of TiO2 one-dimensional (1D) nanowires (NWs) on alumina substrates by the thermal oxidation technique. RF magnetron sputtering was used to deposit a thin Ti metallic layer on the alumina substrate, followed by an Au catalytic layer on the Ti metallic one. Thermal oxidation was carried out in an oxygen deficient environment. The optimal thermal growth temperature was 700◦C, in a mixture environment composed by Ar and O2. As a comparison, Ti films were also oxidized without the presence of the Au catalyst. However, without the Au catalyst, no growth of nanowires was observed. Furthermore, the effect of the oxidation temperature and the film thickness were also investigated. SEM, TEM, and EDX studies demonstrated the presence of Au nanoparticles on top of the NWs, indicating that the Au catalyst drove the growth process. Raman spectroscopy revealed the Rutile crystalline phase of TiO2 NWs. Gas testing measurements were carried out in the presence of a relative humidity of 40%, showing a reversible response to ethanol and H2 at various concentrations. Thanks to the moderate temperature and the easiness of the process, the presented synthesis technique is suitable to grow TiO2 NWs for many different applications
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Highly nonlinear and dispersion-flattened fiber design for ultrafast phase-sensitive amplification
No full textLink to a related website: https://unpaywall.org/10.1109/JLT.2012.2215307, Open Access via UnpaywallThe properties of phase-sensitive amplification (PSA) in highly nonlinear fibers are studied. We present a soft glass fiber designed for high nonlinearity and broadband, low dispersion and simulate its performance as a PSA device for ultrafast bitrate signals at 640 Gb/s. The effect of the fiber design parameters on its PSA performance have been studied and the final design has been optimized using a genetic algorithm to have a high nonlinearity and low, flat dispersion. This design has subsequently been compared to other highly nonlinear fibers in order to highlight the effect of both using soft glass and the design and optimization technique. Modelled fiber performance shows squeezing of phase noise in a 5 m length of fiber with 32 dBm total power in the signal and pumps. The fiber length we have used in our model is two orders of magnitude shorter than the state of the art silica based PSA devices for comparable power levels. In addition, fabrication tolerance modelling is done to show that our fiber design is better able to manage fluctuations in the dispersion due to the high nonlinearity.H. Tilanka Munasinghe, Shahraam Afshar Vahid, and Tanya M. Monr
Gold functionalized MoO3nano flakes for gas sensing applications
No full textMolybdenum trioxide (MoO3) nano flakes (NF) with orthorhombic structure were synthesized by evaporation-condensation method using MoO3 powder as a raw material. Gold (Au) nanoparticles were used as a catalyst, preventing the growth of thick layers of MoO3. Furthermore, Au functionalization was performed by sputtering on pure MoO3 NF for a few seconds, decorating the flakes with Au nanoparticles. Chemical sensing performances were evaluated by introducing CO, NH3, Ethanol, NO2, Methanol, H2 and H2S gases in a syntetic air baseline with a relative humidity of 40% at 25 °C. MoO3 NF shows good sensitivity to Ethanol, Methanol, H2 and H2S gases. Owing to Au functionalization the devices exhibited an excellent response to H2S at an operating temperature of 400 °C: the response was 10 times higher than the pure MoO3, and the detection limit moved toward the ppb range
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
“Metal oxide -based heterostructures for gas sensors”- A review
No full textThis review focuses on the synthesis and chemical sensing characterization of metal oxide heterostructures reported since 2012. Heterostructures exhibit strong interactions between closely packed interfaces, showing superior performances compared to single structures. Surface effects appear thanks to the magnification of nanostructures’ surface leading to an enhancement of surface related properties (the base of chemical sensors working mechanism). The combination of different metal oxides to form heterostructures further improves the selectivity and/or other important sensing parameters. A very large number of different morphologies and structures have been proposed, each one exhibiting peculiar sensing properties towards specific chemical compounds. Among the different preparation methodologies, a significant number has been performed by means of hydrothermal method. However, the combination of various fabrication methods seems a very efficient strategy to obtain metal oxide-based heterostructures with different morphologies and dimensions such as core-shell nanostructures, one-dimensional heterostructures, two-dimensional layered heterojunctions, and three-dimensional hierarchical heterostructures. Despite all extraordinary advances in both material science and nanotechnology and the results achieved with heterostructured chemical sensors, there are few points that still deserve further studies and investigations, such as possible diffusion across the junctions, reproducibility of the fabrication process, synergistic or catalytic effects among the materials forming the heterostructures and influence/stability of the contacts. Moreover, perfect control over their growth is mandatory for their application in commercial devices. Only a careful understanding of the growth and the interface properties could fill the existing gap between laboratory studies and real-world exploitation of these heterostructures
Low temperature gas sensing properties of Graphene Oxide/SnO2 nanowires composite for H-2
No full textIn this work Graphene Oxide (GO) and SnO2 nanowires (NWs) composite
sensing performance were studied. Single crystal SnO2 NWs were directly
grown by thermal evaporation method and GO was successfully synthesized
using modified Hummers method. RF magnetron sputtered Pt particles were
used as a catalyst for the growth of SnO2 NWs. Drop cast technique was
used to deposited GO on top of the SnO2 NWs. FE-SEM (LEO 1525) was used
to investigate the morphology of SnO2 NWs and GO. Fabricated sensors
were tested towards various concentration of H-2 at different working
temperatures. This GO/SnO2 hybrid sensors show a reversible response to
H-2 at low operating temperature. (C) 2016 The Authors. Published by
Elsevier Ltd
Fabrication and properties of lead-germanate glasses for high nonlinearity fibre applications
No full textPaper Tu.3.A.5We report on the fabrication of novel germanate glasses and fibres. We have characterised the glasses in terms of their thermal properties, Raman spectra and refractive indices (both linear and nonlinear) and present them as viable alternatives to tellurite glasses for soft glass optical fiber applications.H. Tilanka Munasinghe, Anja Winterstein-Beckmann, Christian Schiele, Lothar Wondraczek, Danilo Manzani, Shahraam Afshar V., Tanya M. Monro, and Heike Ebendorff-Heidepriemhttp://www.ecoc2013.org
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