Typically, Cu(In,Ga)Se2 (CIGS) thin films for photovoltaic devices are deposited by co-evaporation or, alternately, by deposition of the metals with or followed by treatment in a selenium ...environment. In this article, we describe CIGS films that are instead deposited by RF magnetron sputtering from a single quaternary target without any additional selenization. Devices built with these films exhibit efficiencies as high as 8.9%. We demonstrate that deposition power can be varied in order to change the film morphology and improve device performance.
The chalcogen glasses (i.e., glasses based on the elements S, Se, and Te) are transparent in the infrared (IR), possess low phonon energies, are chemically durable, and can be drawn into fiber. We ...review our recent research progress at the Naval Research Laboratory (NRL) to develop chalcogenide glass fibers for applications in the mid- and long-wave IR wavelength regions from 2 to 12μm. Our recent effort in the development of low loss chalcogenide fibers, by describing the synthesis and purification methods, fiber drawing techniques, and highlighting the best results, is summarized. Various applications of these high quality chalcogenide fibers, including multimode beam combiners, mid-infrared supercontinuum sources, fiber Bragg gratings, fiber bundles for IR imaging, anti-reflecting surface structures, and modal filters, are described. Novel infrared (IR) lenses that enable a reduction in the size and weight of IR imaging optics through the use of layered glass structures with broad IR transmission are also presented.
•Recent research progress at NRL in chalcogenide glass fibers is reviewed.•Synthesis, purification, fiber drawing techniques, and the results are summarized.•Various applications of these high quality chalcogenide fibers are presented.
The mid-wave IR and long-wave IR laser potential of rare-earth ions in chalcogenide glass fiber is reviewed. Spectroscopic data for the mid-wave and long-wave IR transitions for Pr/sup 3+/, Dy/sup ...3+/, and Tb/sup 3+/ in chalcogenide glass is presented and used as a basis for discussion of laser potential in these glasses.
The polymers IP-Dip, IP-L, and IP-S are among the most commonly used photo-resists employed for the rapid prototyping of optical components using two-photon polymerization. Despite the widespread use ...of these polymers, measured data on their optical properties is scarce. Recently, the refractive index ð'> of these polymers has been determined in the visible and near-infrared spectral range. However, the accurate optical properties including extinction coefficient ðoe... in the ultraviolet spectral range have not been reported yet. Here we report on accurate, ellipsometric measurements of the complex dielectric functions of two-photon polymerized IP-Dip, IP-L, and IP-S in the spectral range from 210 nm to 1500 nm. Model dielectric functions composed of oscillators with Lorentz, Gaussian, and Tauc-Lorentz broadenings are presented for all investigated polymers.
Summary Huge success has been noted internationally in reducing catheter-related bloodstream infection with ‘care bundles’ for central venous catheters in intensive care units. A multidisciplinary ...team from the Infectious Diseases Unit at Ninewells Hospital, Dundee designed a ‘bundle’ for peripheral venous catheters (PVCs) based on drafts developed by Health Protection Scotland (details available online). A senior medical student collected weekly data, carried out monthly ‘plan, do, study, act’ (PDSA) cycles and displayed the results on the ward in real time. Data consisted of measures to assess objectively clinical performance for insertion (recording date, indication and location) and maintenance (daily review of necessity, clinical appearance of site, duration less than 72 h and timely removal). Care bundle compliance was assessed for each patient and percentage compliance plotted weekly. The initial compliance of 54% improved by 1.11% per week to 82% (95% confidence interval: 0.6–1.6%; P = 0.0001). This was attributed to multiple interventions including daily assessment of PVC necessity, weekly audit and feedback, monthly patient safety meetings to discuss issues with compliance, the introduction of new PVC dressings and the promotion of new PVC care plans. In conclusion, we demonstrated a significant improvement in PVC management on a single unit by using a care bundle approach. In order to improve compliance, further implementation of the PVC care bundle throughout the hospital has been necessary.
High purity chalcogenide glasses were prepared in the series As2S(3−x)Sex where x=0 to 3. The measured third order non-linearities increase with the value of x, and are up to about 1000 times larger ...than silica for As2Se3 glass. We show that the anharmonic oscillator model, using the normalized photon energy, gives an excellent fit to the data over three orders of magnitude. Single mode optical fibers based on As2S3 and As2Se3 glasses have been fabricated using the double crucible technique and the Stimulated Brillouin Scattering (SBS) investigated. The threshold intensity for the SBS process was measured and used to estimate the Brillouin gain coefficient. Preliminary results indicate record high values for the figure of merit and theoretical gain, compared to silica, which bodes well for slow-light based applications in chalcogenide fibers.
We report the first demonstration of high bit rate signal processing by a fiber-based photonic wire. We achieve 160 Gb/s demultiplexing via four wave mixing in a 1.9 microm diameter photonic wire ...tapered from As(2)S(3) chalcogenide glass single mode fibre, with very low pump power requirements ( < 20 mW average power, 0.45 W peak power), enabled by a very high nonlinearity (gamma approximately 7850 W(-1) km (-1) ) and greatly reduced dispersion.
Complicated intra-abdominal infections (cIAIs) are associated with significant morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with cIAI in a ...multicentre study and to develop clinical prediction models (CPMs) to help identify patients at risk of mortality or relapse.
A multicentre observational study was conducted from August 2016 to February 2017 in the UK. Adult patients diagnosed with cIAI were included. Multivariable logistic regression was performed to develop CPMs for mortality and cIAI relapse. The c-statistic was used to test model discrimination. Model calibration was tested using calibration slopes and calibration in the large (CITL). The CPMs were then presented as point scoring systems and validated further.
Overall, 417 patients from 31 surgical centres were included in the analysis. At 90 days after diagnosis, 17.3 per cent had a cIAI relapse and the mortality rate was 11.3 per cent. Predictors in the mortality model were age, cIAI aetiology, presence of a perforated viscus and source control procedure. Predictors of cIAI relapse included the presence of collections, outcome of initial management, and duration of antibiotic treatment. The c-statistic adjusted for model optimism was 0.79 (95 per cent c.i. 0.75 to 0.87) and 0.74 (0.73 to 0.85) for mortality and cIAI relapse CPMs. Adjusted calibration slopes were 0.88 (95 per cent c.i. 0.76 to 0.90) for the mortality model and 0.91 (0.88 to 0.94) for the relapse model; CITL was -0.19 (95 per cent c.i. -0.39 to -0.12) and - 0.01 (- 0.17 to -0.03) respectively.
Relapse of infection and death after complicated intra-abdominal infections are common. Clinical prediction models were developed to identify patients at increased risk of relapse or death after treatment, these now require external validation.
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