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AlInGaP LEDs are widely used in illumination applications as automotive and signalization due their low consumption and high durability. In order to verify the high durability data it is necessary to consider not only catastrophic failures but also degradation. In this work LEDs degradation at different temperature and drive current accelerated tests have(More)
A temperature stress test was carried out on GaAs single-junction solar cells to analyze the degradation suffered when working at ultra-high concentrations. The acceleration of the degradation was realized at two different temperatures: 130 °C and 150 °C. In both cases, the degradation trend was the same, and only gradual failures were observed. A fit of(More)
Accelerated testing is a necessary tool in order to demonstrate the reliability of concentration photovoltaic solar cells, devices which is expected to be working not less than 25 years. Many problems arise when implementing high temperature accelerated testing in this kind of solar cells, because the high light irradiation level, at which they work, is(More)
Measurement of dynamic cerebral autoregulation (CA), the transient response of cerebral blood flow (CBF) to changes in arterial blood pressure (ABP), has been performed with an index of autoregulation (ARI), related to the parameters of a second-order differential equation model, namely gain (K), damping factor (D) and time constant (T). Limitations of the(More)
ESO spectra of HD 65949 show it to be unlike any of the well-known types within its temperature range ≈ 13600K. It is neither a silicon, nor a mercury-manganese star, though it has a huge Hg II line at λ3984. We estimate log(Hg/H)+12.0 ≈ 7.4. This is higher than any published stellar mercury abundance. HD 65949 is a member of a nearby open cluster, NGC(More)
This work analyzes the long-term functionality of HP (High-power) UV-LEDs (Ultraviolet Light Emitting Diodes) as the exciting light source in non-contact, continuous 24/7 real-time fluoro-sensing pollutant identification in inland water. Fluorescence is an effective alternative in the detection and identification of hydrocarbons. The HP UV-LEDs are more(More)
On the basis of our new simultaneous photome-try and spectroscopy (885 uvby differential measurements in 11 nights and 154 spectrograms of the FeIIλ4508 region in 5 nights), we can detect 12 probable periodicities in the variability pattern of this star, determining the frequencies of 7 without any ambiguity. Through a direct fit of pulsational models to(More)
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