Magnetron oscillators with pulse to pulse frequency agility are used in radar service to provide ECCM capability and to provide target signal enhancement by reduction of glint and clutter return ...signals. A family of frequency agile coaxial magnetrons called "dither-tuned" tubes has been developed for this service. They are tuned by a motor driven eccentric or cam connected to the oscillator cavity tuner. Initial 200 kilowatt peak power, X band tubes of this class operated with a near sinusoidal frequency tuning mode over typical tuning ranges of 40 to 80 MHz at 75 Hz tuning rates. A readout voltage signal related to the oscillator frequency for slaving the receiver local oscillator to the transmitter was derived from a resolver directly coupled to the shaft of the eccentric. The resolver is a transformer with a rotating secondary winding. 100 KHz AC voltage applied to the primary produces an output AC voltage proportional to the angular position of the eccentric and hence the tuner position and frequency.
Objectives: The cytokine interleukin (IL)-1 mediates ischaemic brain damage in rodents. The endogenous, highly selective, IL-1 receptor antagonist (IL-1ra) protects against ischaemic cerebral injury ...in a range of experimental settings, and IL-1ra causes a marked reduction of cell death when administered peripherally or at a delay in transient cerebral ischaemia. We report here the first randomised, double blind, placebo controlled trial of recombinant human IL-1ra (rhIL-1ra) in patients with acute stroke. Methods: Patients within 6 hours of the onset of symptoms of acute stroke were randomised to rhIL-1ra or matching placebo. Test treatment was administered intravenously by a 100 mg loading dose over 60 seconds, followed by a 2 mg/kg/h infusion over 72 h. Adverse events and serious adverse events were recorded for up to 3 months, serial blood samples were collected for biological markers up to 3 months, and 5–7 day brain infarct volume was measured by computed tomography. Results: No adverse events were attributed to study treatment among 34 patients randomised. Markers of biological activity, including neutrophil and total white cell counts, C reactive protein, and IL-6 concentrations, were lower in rhIL-1ra treated patients. Among patients with cortical infarcts, clinical outcomes at 3 months in the rhIL-1ra treated group were better than in placebo treated. Conclusions: These data suggest that rhIL-1ra is safe and well tolerated in acute stroke. In addition, rhIL-1ra exhibited biological activity that is relevant to the pathophysiology and clinical outcome of ischaemic stroke. Our findings identify rhIL-1ra as a potential new therapeutic agent for acute stroke.
In this study cadmium stannate Cd2SnO4 (CTO), was sputtered onto borosilicate glass under substrate temperatures of ~25°C (room temp), 200°C, 300°C and 400°C. The CTO films were then annealed in ...contact with cadmium sulfide (CdS). This annealing process consisted of placing the CTO samples face up in a thermal furnace with a separate piece of CdS film on a borosilicate substrate face down on top of the CTO sample. This arrangement was then heated to a temperature of 600°C and annealed for one hour. The goal was to fabricate a CTO film with the highest transparency without sacrificing good electrical conductivity. The quality of CTO films, i.e. transparency and electrical conductivity can be greatly affected by processing conditions. In this paper the optical and electrical properties of CTO are investigated before and after thermal annealing to determine the affect of varying process conditions on the quality of the film. Spectroscopic ellipsometry analysis was performed on both as-deposited and annealed CTO to determine the nature of the optical response of the films over the spectral range of 0.73 to 3.34eV. The electrical properties of the films were examined using both Hall effect data and optical Drude modeling of free carrier absorption. Structural properties of the films were determined from X-ray diffraction data. The result of this investigation is a high quality CTO film with a sheet resistance of ~8Ω/□.
•Cadmium stannate (CTO) is characterized to achieve optimization as a transparent conducting oxide (TCO).•Spectroscopic ellipsometry results were substantiated with other measurements.•Specialized CTO processing yields a TCO film with low sheet resistance.
Four applications of real-time spectroscopic ellipsometry (RTSE) and ex-situ mapping spectroscopic ellipsometry (SE) in thin-film hydrogenated silicon (Si:H) photovoltaics (PV) technology are ...reviewed with the common theme being the development and application of SE-derived growth evolution diagrams. The goals of these applications are to understand and consequently further advance this technology. In the first application, fabrication of engineered thin films consisting of periodic arrays of silicon (Si) nanocrystallites in an amorphous Si:H (a-Si:H) host matrix has been guided by a growth evolution diagram developed by RTSE for radio-frequency plasma-enhanced chemical vapor deposition (PECVD) using SiH4+H2 mixtures. Such precisely controlled microstructures are of interest as possible intrinsic-layer components of p–i–n and n–i–p thin-film PV devices, and RTSE is shown to be a key technique for guidance in fabrication and for structure verification. In the second application of growth evolution diagrams, very-high-frequency PECVD intrinsic a-Si:H, hydrogenated amorphous silicon–germanium alloys (a-Si1−xGex:H), and hydrogenated nanocrystalline silicon (nc-Si:H) have been investigated for use as the top, middle, and bottom-cell i-layer components, respectively, of triple-junction n–i–p solar cells. The growth evolution diagram for the bottom-cell i-layer, starting from an underlying mixed-phase amorphous+nanocrystalline silicon (a+nc)-Si:H n-layer, reveals a bifurcation at a critical H2-dilution flow ratio R (R=H2/Si2H6, in this application) between mixed-to-amorphous phase evolution (a+nc)→a at low R and mixed-to-nanocrystalline phase evolution (a+nc)→nc at high R. The highest performance single-step nc-Si:H solar cell is found at minimal R while remaining on the nanocrystalline side of the identified bifurcation where suitable grain boundary passivation can be assured. Because of the importance of the roll-to-roll flexible substrate configuration in such multijunction Si:H-based PV technology, RTSE has been demonstrated in a third application for monitoring PECVD of a-Si:H n–i–p solar cell structures on back-reflector-coated flexible roll-to-roll polymer substrates. RTSE has been used for probing along the center line of the moving substrate during deposition, and ex-situ mapping SE has been used over the full substrate area after deposition. Detailed studies of the top-most p-layer of the n–i–p solar cell have been performed, with the goal being to develop spatially-dependent (in contrast to R-dependent) growth evolution diagrams in order to evaluate uniformity across the width of the substrate and thus to enable optimization of the resulting a-Si:H PV modules. In this study, efficiency optimization occurs at the p-layer transition region in which a-Si:H nucleates from the i-layer surface, but evolves to predominantly nc-Si:H for improved contact to the top-most In2O3:Sn layer. In the fourth and final application reviewed here, the mapping-SE-deduced properties of the Si:H i and p-layers have been spatially correlated with device performance parameters from an array of n–i–p a-Si:H-based dot cells over a 13×13cm2 substrate area. Analysis of the SE data acquired over the full area provides property maps of i-layer thickness and band gap, p-layer thickness and band gap, and p-layer surface roughness thickness for the n–i–p structure. The mapped values adjacent to the PV devices have been correlated with the device performance parameters. When sufficient non-uniformity exists, these correlations enable optimization based on specific ranges of values that characterize the fundamental properties of the material and the film structure.
•Growth evolution diagrams from real time spectroscopic ellipsometry have guided plasma-enhanced chemical vapor deposition of silicon-based thin films.•Optimum amorphous silicon-germanium alloys are deposited using maximum hydrogen dilution while avoiding nanocrystallity within the solar cell i-layer thickness.•Optimum nanocrystalline silicon for solar cells is deposited using minimum hydrogen dilution while avoiding the transition to amorphous phase growth.•Real time spectroscopic ellipsometry is demonstrated for monitoring a‑Si:H n‑i-p solar cell deposition on flexible roll-to-roll polymer substrates.•Properties of Si:H i and p-layers deduced from mapping spectroscopic ellipsometry have been spatially correlated with solar cell performance parameters.
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