766 research outputs found
Ontoverse: Collaborative Knowledge Management in the Life Sciences Network
This paper regards the two aspects of knowledge networking: data networks for information integration and social networks for information sharing in communities. The importance of ontologies as a means for effective information integration is discussed and related to the current Web 2.0 trends. The Ontoverse ontology wiki is introduced as a tool for collaborative ontology engineering and knowledge management with particular focus on interlinking the research community within the life sciences
183 Pseudomonas aeruginosa acquisition in CF patients in the context of otorhinolarynological surgery or dentist attendance – Case series and discussion of preventive concepts
Time resolved investigation of Cu In,Ga Se2 growth and Ga gradient formation during fast selenization of metallic precursors
Ga segregation at the backside of Cu In,Ga Se2 solar cell absorbers is a commonly observed phenomenon for a large variety of sequential fabrication processes. Here, we investigate the correlation between Se incorporation, phase formation and Ga segregation during fast selenisation of Cu In Ga precursor films in elemental selenium vapour. Se incorporation and phase formation are analysed by real time synchrotron based X ray diffraction and fluorescence analysis. Correlations between phase formation and depth distributions are gained by interrupting the process at several points and by subsequent ex situ cross sectional electron microscopy and Raman spectroscopy. The presented results reveal that the main share of Se incorporation takes place within a few seconds during formation of In Se at the top part of the film, accompanied by outdiffusion of In out of a ternary Cu In Ga phase. Surprisingly, CuInSe2 starts to form at the surface on top of the In Se layer, leading to an intermediate double graded Cu depth distribution. The remaining Ga rich metal phase at the back is finally selenised by indiffusion of Se. On the basis of a proposed growth model, we discuss possible strategies and limitations for the avoidance of Ga segregation during fast selenisation of metallic precursors. Solar cells made from samples selenised with a total annealing time of 6.5 amp; 8201;min reached conversion efficiencies of up to 14.2 total area, without anti reflective coating . The evolution of the Cu In,Ga Se2 diffraction signals reveals that the minimum process time for high quality Cu In,Ga Se2 absorbers is limited by cation ordering rather than Se incorporatio
Parametric Waveform Synthesis: a scalable approach to generate sub-cycle optical transients
The availability of electromagnetic pulses with controllable field waveform
and extremely short duration, even below a single optical cycle, is imperative
to fully harness strong-field processes and to gain insight into ultrafast
light-driven mechanisms occurring in the attosecond time-domain. The recently
demonstrated parametric waveform synthesis (PWS) introduces an energy-, power-
and spectrum-scalable method to generate non-sinusoidal sub-cycle optical
waveforms by coherently combining different phase-stable pulses attained via
optical parametric amplifiers. Significant technological developments have been
addressed to overcome the stability issues related to PWS and to obtain an
effective and reliable waveform control system. Here we present the main
ingredients enabling PWS technology. The design choices concerning the optical,
mechanical and electronic setups are justified by analytical/numerical modeling
and benchmarked by experimental observations. In its present incarnation, the
PWS technology enables the generation of field-controllable mJ-level
few-femtosecond pulses spanning the visible to infrared range.Comment: 34 page
CdS/Cu(In,Ga)S2 based solar cells with efficiencies reaching 12.9% prepared by a rapid thermal process
In this letter, we report externally confirmed total area efficiencies
reaching up to 12.9% for CdS/Cu(In,Ga)S2 based solar cells. These are the
highest externally confirmed efficiencies for such cells. The absorbers were
prepared from sputtered metals subsequently sulfurized using rapid thermal
processing in sulfur vapor. Structural, compositional, and electrical
properties of one of these champion cells are presented. The correlation
between the Ga distribution profile and solar cell properties is discussed
Presentation of the ISRM mine closure state of the art report
International audienceIn 2005, Prof. Nielen Van der Merwe, at that time President of the ISRM, initiated a commission to facilitate the constitution of an international network of experts involved in mine closure and post-mining management. Eight experts coming from different countries have been deeply involved in this ISRM 'mine closure commission', for four years. Closure of mining operations does not lead to the complete elimination of risks likely to affect the surface above old mine workings. Therefore, disorders potentially harmful for people and goods may develop, sometimes just after the closure but also, in some cases, long time after. The first mandate of the commission has been dedicated to the elaboration of a state-ofthe- art report presenting, at an international scale, the mine closure problem (context, main risks of disorders, major hazard assessment methods and treatment techniques). The present paper presents an outline of this ISRM report that members may download on the ISRM website
Real time observation of Cu2ZnSn S,Se 4 solar cell absorber layer formation from nanoparticle precursors
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