Publications by authors named "S Ester"

Zinc tin oxide (ZTO) is investigated as a photoluminescent sensor for oxygen (O); chemisorbed oxygen quenches the luminescence intensity. At the same time, ZTO is also studied as a resistive sensor; being an n-type semiconductor, its electrical conductance decreases by adsorption of oxygen. Both phenomena can be exploited for quantitative O sensing.

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Luminescence type gas sensors based on organic luminophores are characterized by an excellent signal stability over the luminophores' lifetime. Even though the sensing material is prone to degradation due to photobleaching, evaluation of the dynamic optical response allows to minimize aging induced drift effects of the luminophore and the optoelectronic components. The gas dependent luminophore decay time is mostly independent of the excitation intensity, which is attributed to the monomolecular recombination in many organic luminophores.

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New approaches to pattern recognition and modeling using neural networks also provide powerful tools for the analysis of heart sounds in the diagnosis of heart failure. This paper describes how a neutral network can be used to estimate the duration of systolic and diastolic heart phases as well as to suggest a suitable diagnosis. A neural network-based auscultation system is capable of documenting and analysing a heart sound signal by applying methods similar to those used by physicians in the subjective interpretation of stethoscopic signals.

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