Investigation of emitter homogeneity on laser doped emitters

The selective emitter formation by laser doping is a well known process to increase the efficiency of silicon solar cells [1], [2]. For the characterization of laser doped emitters, SIMS (Secondary Ion Mass Spectroscopy) and ECV (Electrochemical Capacitance Voltage Measurement) techniques are used to analyze the emitter profile [3]. It is very difficult to get acceptable result by SIMS on a textured surface, so only ECV can be used. It has been shown, that a charge carrier depth profile can be measured on a homogeneous emitter only by ECV. The use of laser doping results in a non-homogeneous emitter. We have shown that the emitter depth is not just a function of the pulse power, but in addition of the surface structure of the wafer. The texture seems responsible for a strong variability in the doping profile. It has been shown, that the ECV measurement is not applicable to characterize the emitter depth on laser doped areas, because of the microscopic inhomogeneities in the emitter on the macroscopic measurement area. The real emitter profiles are to complex to be characterized by SIMS or ECV. We have shown that the variation in the emitter profile is resulting from the texture in the laser-doped regions

Investigation of emitter homogeneity on laser doped emitters

The selective emitter formation by laser doping is a well known process to increase the efficiency of silicon solar cells [1], [2]. For the characterization of laser doped emitters, SIMS (Secondary Ion Mass Spectroscopy) and ECV (Electrochemical Capacitance Voltage Measurement) techniques are used to analyze the emitter profile [3]. It is very difficult to get acceptable result by SIMS on a textured surface, so only ECV can be used. It has been shown, that a charge carrier depth profile can be measured on a homogeneous emitter only by ECV. The use of laser doping results in a non-homogeneous emitter. We have shown that the emitter depth is not just a function of the pulse power, but in addition of the surface structure of the wafer. The texture seems responsible for a strong variability in the doping profile. It has been shown, that the ECV measurement is not applicable to characterize the emitter depth on laser doped areas, because of the microscopic inhomogeneities in the emitter on the macroscopic measurement area. The real emitter profiles are to complex to be characterized by SIMS or ECV. We have shown that the variation in the emitter profile is resulting from the texture in the laser-doped regions

Synchronous Constructive Cryptography

This paper proposes a simple synchronous composable security framework as an instantiation of the Constructive Cryptography framework, aiming to capture minimally, without unnecessary artefacts, exactly what is needed to state synchronous security guarantees. The objects of study are specifications (i.e., sets) of systems, and traditional security properties like consistency and validity can naturally be understood as specifications, thus unifying composable and property-based definitions. The framework\u27s simplicity is in contrast to current composable frameworks for synchronous computation which are built on top of an asynchronous framework (e.g. the UC framework), thus not only inheriting artefacts and complex features used to handle asynchronous communication, but adding additional overhead to capture synchronous communication. As a second, independent contribution we demonstrate how secure (synchronous) multi-party computation protocols can be understood as constructing a computer that allows a set of parties to perform an arbitrary, on-going computation. An interesting aspect is that the instructions of the computation need not be fixed before the protocol starts but can also be determined during an on-going computation, possibly depending on previous outputs

Insulin Glargine in the Intensive Care Unit: A Model-Based Clinical Trial Design

Online 4 Oct 2012Introduction: Current succesful AGC (Accurate Glycemic Control) protocols require extra clinical effort and are impractical in less acute wards where patients are still susceptible to stress-induced hyperglycemia. Long-acting insulin Glargine has the potential to be used in a low effort controller. However, potential variability in efficacy and length of action, prevent direct in-hospital use in an AGC framework for less acute wards. Method: Clinically validated virtual trials based on data from stable ICU patients from the SPRINT cohort who would be transferred to such an approach are used to develop a 24-hour AGC protocol robust to different Glargine potencies (1.0x, 1.5x and 2.0x regular insulin) and initial dose sizes (dose = total insulin over prior 12, 18 and 24 hours). Glycemic control in this period is provided only by varying nutritional inputs. Performance is assessed as %BG in the 4.0-8.0mmol/L band and safety by %BG<4.0mmol/L. Results: The final protocol consisted of Glargine bolus size equal to insulin over the previous 18 hours. Compared to SPRINT there was a 6.9% - 9.5% absolute decrease in mild hypoglycemia (%BG<4.0mmol/L) and up to a 6.2% increase in %BG between 4.0 and 8.0mmol/L. When the efficacy is known (1.5x assumed) there were reductions of: 27% BG measurements, 59% insulin boluses, 67% nutrition changes, and 6.3% absolute in mild hypoglycemia. Conclusion: A robust 24-48 clinical trial has been designed to safely investigate the efficacy and kinetics of Glargine as a first step towards developing a Glargine-based protocol for less acute wards. Ensuring robustness to variability in Glargine efficacy significantly affects the performance and safety that can be obtained

SCALA: In situ calibration for integral field spectrographs

International audienceThe scientific yield of current and future optical surveys is increasingly limited by systematic uncertainties in the flux calibration. This is the case for Type Ia supernova (SN Ia) cosmology programs, where an improved calibration directly translates into improved cosmological constraints. Current methodology rests on models of stars. Here we aim to obtain flux calibration that is traceable to state-of-the-art detector-based calibration. We present the SNIFS Calibration Apparatus (SCALA), a color (relative) flux calibration system developed for the SuperNova Integral Field Spectrograph (SNIFS), operating at the University of Hawaii 2.2 m (UH 88) telescope. By comparing the color trend of the illumination generated by SCALA during two commissioning runs, and to previous laboratory measurements, we show that we can determine the light emitted by SCALA with a long-term repeatability better than 1%. We describe the calibration procedure necessary to control for system aging. We present measurements of the SNIFS throughput as estimated by SCALA observations. The SCALA calibration unit is now fully deployed at the UH\,88 telescope, and with it color-calibration between 4000 {\AA} and 9000 {\AA} is stable at the percent level over a one-year baseline

Das Wissen der Fraunhofer-Gesellschaft: Pragmatische Wege zum "Open Access"

Gemeinsam mit anderen Deutschen Forschungsorganisationen hat auch die Fraunhofer-Gesellschaft die "Berliner Erklärung über den offenen Zugang zu wissenschaftlichem Wissen" unterzeichnet. Fraunhofer ist mit 80 Forschungseinrichtungen und 15.000 Mitarbeitern die größte Europäische Organisation für angewandte Forschung. Der Fokus auf industrienahe, angewandte Forschung schränkt die Möglichkeiten aktiver Beiträge zum "Open Access" jedoch ein. So haben Patentschriften für Fraunhofer eine ganz herausragende Bedeutung. Viele Veröffentlichungsaktivitäten haben - zumindest auch - Aquisitionscharakter für die Vertragsforschung. Neben Messeauftritten und Präsentationen auf Tagungen spielen daher Artikel in industrienahen Fachmagazinen eine wichtige Rolle. Die Intentionen des "Open Access" erscheinen demgegenüber eher universitär und an den Interessen der Grundlagenforschung orientiert. Nur ein relativ kleiner Teil der Fraunhofer-Publikationen sind originäre Veröffentlichungen im strikten Sinne des "Open Access". Zusätzlich können jedoch auch Fachbeiträge in wissenschaftlichen Fachzeitschriften oft im Rahmen der sogenannten "green road" parallel online veröffentlicht werden. Die Heterogenität der Fraunhofer-Veröffentlichungen zwingt also zu pragmatischen Herangehensweisen, Zugangsmöglichkeiten zu optimieren. Eigene Reports können direkt auf dem eigenen Volltext-Repository veröffentlicht werden. Wo zulässig, werden Fachaufsätze parallel im Volltext angeboten, je nach den Vertragsbedingungen der Verlage als Pre- oder Postprint. Auch Dissertationen, die im Kontext der Fraunhofer-Forschung entstanden sind, werden teilweise hier veröffentlicht . Jedoch werden auch fremde URLs verlinkt, dort, wo Frauhofer keine Rechte an den Volltexten hat. Schließlich bieten die DOI (digital object identifier) der Fachverlage und Fachgesellschaften weitere eingeschränkte - meist kostenpflichtige - Zugriffsmöglichkeiten. Richtziel aller Maßnahmen bleibt jedoch der freie Zugang zu Wissen für die Forschung