40 results on '"Agfa-Gevaert"'
Search Results
2. Mitteilungen aus den Forschungslaboratorien der Agfa Leverkusen-München
- Author
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Agfa-Gevaert Gruppe and Agfa-Gevaert Gruppe
- Subjects
- Engineering
- Abstract
In dem vorliegenden Band werden wieder die Ergebnisse einiger in den Agfa Laboratorien durchgeführten Arbeiten mitgeteilt. Die Themen zu diesen Arbeiten sind den verschiedensten Bereichen der photographischen Forschung entnommen, doch sind zwei Gebiete besonders stark berücksichtigt worden, welche heute eine hervorragende Rolle spielen. Einmal ist es die Anwendung der Ergebnisse der Halb leiterphysik zur Erklärung des photographischen Elementarprozesses und der Entwicklungsvorgänge. An sich ist die photographische Anwendung dieses Zweiges der Physik nicht neu, doch ist er durch neue Forschungsergebnisse und Betrachtungs weisen für die Theorie des photographischen Prozesses in letzter Zeit besonders fruchtbar geworden. Das zweite Thema ist die Anwendung der Übertragungstheorie und der Informationstheorie auf photographische Probleme. Ursprünglich in der elektrischen Nachrichtentechnik entwickelt, wurden diese Disziplinen in steigendem Maße auf optische und photographische Probleme angewendet. Da die Grundlagen dieser Methoden vielen Lesern unbekannt sein dürften, wurden sie in einem längeren Aufsatz behandelt. Dieser Band ist Herrn Direktor Dr. ALFRED MILLER, dem langjährigen Leiter der Agfa Filmfabrik in Wolfen gewidmet, durch dessen Tatkraft und Erfahrung nach dem Kriege die Filmfabrik in Leverkusen aufgebaut und auf den heutigen Stand gebracht werden konnte. Ihm ist vor allem auch zu danken, daß durch Gründung des Wissenschaftlich-Photographischen Laboratoriums die wissenschaftliche Forschung auf photographischem Gebiet wieder aufgenommen wurde. An den Arbeiten zur Herausgabe des vorliegenden Bandes war Herr Dr. habil. E. KLEIN in starkem Maße beteiligt. Für seine wertvolle Unterstützung bin ich ihm zu Dank verpflichtet.
- Published
- 2013
3. Preparation of Tailor-Made Multifunctional Propenyl Ethers by Radical Copolymerization of 2-(1-Propenyl)oxyethyl Methacrylate
- Author
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Etienne Schacht, Stefan Vansteenkiste, Joan Agfa-Gevaert Vermeersch, Gert Matthijs, F. C. De Schrijver, and M. Van Damme
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Propenyl ,chemistry.chemical_classification ,Polymers and Plastics ,Chemistry ,Organic Chemistry ,Radical polymerization ,Cationic polymerization ,Polymer ,Methacrylate ,Inorganic Chemistry ,chemistry.chemical_compound ,Monomer ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Organic chemistry ,Trifluoromethanesulfonate - Abstract
A new approach for preparation of multifunctional polymers with pendant vinyl ethers was investigated. In particular, 2-(1-propenyl)oxyethyl methacrylate, a new ambifunctional monomer combining easy radical polymerization and a fast cationically cross-linkable group, was evaluated. Hence, the physical characteristics of copolymers were controlled by the selection of comonomers. Cross-linking kinetics as a function of temperature and concentration of the acid-generating species were monitored quantitatively by FT-IR spectroscopy. Through the use of DSC measurements, the onset for cationic polymerization was determined. It was demonstrated that both 9-fluorenylideneimino-p-toluenesulfonate and diphenyliodonium triflate could be used as efficient thermally initiating cross-linking agents.
- Published
- 1998
4. Labile polycarbonates containing azo units susceptible to thermolytic or acidolytic degradation
- Author
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Oskar Nuyken, Joan Agfa-Gevaert Vermeersch, Robert Gärtner, M. Van Damme, and Brigitte Voit
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chemistry.chemical_classification ,Materials science ,Molar mass ,Polymers and Plastics ,Cyclohexane ,General Chemical Engineering ,Thermal decomposition ,Diol ,General Chemistry ,Polymer ,chemistry.chemical_compound ,Crystallinity ,chemistry ,Polymer chemistry ,Materials Chemistry ,Organic chemistry ,Thermal stability ,Glass transition - Abstract
Co- and terpolycarbonates containing thermosensitive cycloallylic, benzylic or tertiary diols and, in addition, labile azo functionalities were synthesized in solution from bis(imidazole-carboxylate)s under phase-transfer conditions. The azo groups were introduced by using 2,2'azobis(2-methylpropanol) (1) and azobis(1-hydroxymethyl)cyclohexane (2) as diol components. All copolymers were obtained as amorphous, soft materials with glass transition temperatures below 30°C. Partial crystallinity, however, could be obtained in terpolycarbonates, leading to improved mechanical stability of the products. The polymers were obtained with molar masses Mn in the range 6000-12 900 g/mol. Depending on the structure, the polymers decomposed between 180 and 220°C in a clean, fast, and exothermic process, liberating mostly volatile products. The thermal lability of the azo moieties 1 and 2 was similar to that of the labile carbonate units. In the presence of acids, the thermal stability was drastically reduced and the de...
- Published
- 1998
5. Water-soluble photoresins based on polymeric azo compounds
- Author
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Oskar Nuyken, Joan Agfa-Gevaert Vermeersch, M. Van Damme, Brigitte Voit, W. De Winter, Peter Matusche, and L. Alaerts
- Subjects
chemistry.chemical_classification ,Aqueous solution ,Chemistry ,General Engineering ,Polymer ,Decomposition ,chemistry.chemical_compound ,Water soluble ,Photosensitivity ,visual_art ,Polymer chemistry ,Copolymer ,visual_art.visual_art_medium ,Offset printing ,Methyl methacrylate - Abstract
Polymeric azosulfonates lose their water solubility when exposed to UV light due to decomposition of the azo function. This effect can be used in water-based photoprinting processes. Water-soluble copolymers of azosulfonate containing repeat units and methyl methacrylate have been alternatively synthesized by a polymer-analogous reaction [1,2] and by direct copolymerization [3]. Both polymer types have been evaluated for application as photoresins in offset printing processes. The polymer made by copolymerization is superior and shows excellent results for photosensitivity, resolution, film-forming properties, and development in water, as well as for thermal and moisture storage stability.
- Published
- 1995
6. Abschlussbericht zum BMBF Projekt 'Neue polymere Materialien für die entwicklungsfreie Computer-to-Plate Driographie' : Laufzeit: 1.11.1999 - 31.10.2002, kostenneutrale Verlängerung bis 31.3.03
- Author
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Agfa-Gevaert-Aktiengesellschaft, Grafische Systeme, Offset Printing Systems
- Subjects
Mechanical engineering, power engineering ,Materials science - Abstract
Ill., graph. Darst.
- Published
- 2003
- Full Text
- View/download PDF
7. Self-assembling dyes
- Author
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Vanmaele, Luc, Locculier, J., Meijer, E.W., Janssen, H.H.J.M., Agfa Gevaert, Vanmaele, Luc, Locculier, J., Meijer, E.W., Janssen, H.H.J.M., and Agfa Gevaert
- Abstract
A novel dye according to formula (I): capable of self-assembling thus forming supra-molecular structures. These self-assembling dyes may be advantageously used in an ink-jet ink for improving the stability of ink-jet ink images to light fading.
- Published
- 2004
8. Ink composition containing a particular type of dye, and corresponding ink jet printing process
- Author
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Vanmaele, Luc, Locculier, J., Meijer, E.W., Janssen, H.H.J.M., Fransen, P., Agfa Gevaert, Vanmaele, Luc, Locculier, J., Meijer, E.W., Janssen, H.H.J.M., Fransen, P., and Agfa Gevaert
- Abstract
An ink composition is disclosed which contains a novel type of dye (DYE)n(SAU)m that is capable of self-assembling under appropriate conditions, or is capable of assembling with another analogous dye (DYE')n'(SAU')m', or is capable of assembling with a compound (SAU'')p(X)q, thus forming supramolecular structures. Also disclosed is an ink jet printing process using these novel dyes, and an ink jet printing apparatus provided with an ink cartridge containing such a dye.
- Published
- 2003
9. Radiation stability of CsBr:Eu needle image plates
- Author
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Leblans, P [Agfa Gevaert, Septestraat 27, Mortsel B-2640 (Belgium)]
- Published
- 2009
- Full Text
- View/download PDF
10. Creation of storage centers in CsBr:Eu{sup 2+} needle image plates by vacuum ultraviolet radiation
- Author
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Leblans, P [Agfa Gevaert, Septestraat 27, B-2640 Mortsel (Belgium)]
- Published
- 2009
- Full Text
- View/download PDF
11. Impact of spatial and temporal resolution of rainfall inputs on urban hydrodynamic modelling outputs: A multi-catchment investigation
- Author
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R. Pina, Damian Murlà-Tuyls, Patrick Willems, Ioulia Tchiguirinskaia, G. Bruni, Marie-Claire ten Veldhuis, Li-Pen Wang, Elena Cristiano, Susana Ochoa-Rodriguez, Johan Van Assel, Ricardo Reinoso-Rondinel, Stefan Kroll, Abdellah Ichiba, Bruno Tisserand, Santiago Gaitan, Daniel Schertzer, Christian Onof, Auguste Gires, Hydrologie, Météorologie et Complexité (HM&Co), École des Ponts ParisTech (ENPC), laboratoire Eau Environnement et Systèmes Urbains (LEESU), AgroParisTech-École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Department of Civil and Environmental Engineering [Imperial College London], Imperial College London, and Agfa-Gevaert
- Subjects
Rainfall ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Spatial–temporal resolution ,radar rainfall ,urban hydrology ,0207 environmental engineering ,Drainage basin ,02 engineering and technology ,01 natural sciences ,law.invention ,urban drainage ,law ,MD Multidisciplinary ,X-band radar ,Precipitation ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,Radar ,020701 environmental engineering ,0105 earth and related environmental sciences ,Water Science and Technology ,Hydrology ,geography ,geography.geographical_feature_category ,Storm ,spatialtemporal resolution ,13. Climate action ,Urban hydrology ,Temporal resolution ,[SDE]Environmental Sciences ,Environmental science ,Weather radar ,Spatial variability ,hydrodynamic models ,Surface runoff - Abstract
Urban catchments are typically characterised by high spatial variability and fast runoff processes resulting in short response times. Hydrological analysis of such catchments requires high resolution precipitation and catchment information to properly represent catchment response. This study investigated the impact of rainfall input resolution on the outputs of detailed hydrodynamic models of seven urban catchments in North-West Europe. The aim was to identify critical rainfall resolutions for urban catchments to properly characterise catchment response. Nine storm events measured by a dual-polarimetric X-band weather radar, located in the Cabauw Experimental Site for Atmospheric Research (CESAR) of the Netherlands, were selected for analysis. Based on the original radar estimates, at 100 m and 1 min resolutions, 15 different combinations of coarser spatial and temporal resolutions, up to 3000 m and 10 min, were generated. These estimates were then applied to the operational semi-distributed hydrodynamic models of the urban catchments, all of which have similar size (between 3 and 8 km2), but different morphological, hydrological and hydraulic characteristics. When doing so, methodologies for standardising model outputs and making results comparable were implemented. Results were analysed in the light of storm and catchment characteristics. Three main features were observed in the results: (1) the impact of rainfall input resolution decreases rapidly as catchment drainage area increases; (2) in general, variations in temporal resolution of rainfall inputs affect hydrodynamic modelling results more strongly than variations in spatial resolution; (3) there is a strong interaction between the spatial and temporal resolution of rainfall input estimates. Based upon these results, methods to quantify the impact of rainfall input resolution as a function of catchment size and spatial–temporal characteristics of storms are proposed and discussed. publisher: Elsevier articletitle: Impact of spatial and temporal resolution of rainfall inputs on urban hydrodynamic modelling outputs: A multi-catchment investigation journaltitle: Journal of Hydrology articlelink: http://dx.doi.org/10.1016/j.jhydrol.2015.05.035 content_type: article copyright: Copyright © 2015 The Authors. Published by Elsevier B.V. ispartof: Journal of Hydrology vol:531 issue:2 pages:389-407 status: published
- Published
- 2015
12. Defects in Divided Zinc−Copper Aluminate Spinels: Structural Features and Optical Absorption Properties
- Author
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Gérard Villeneuve, Marco Daturi, Anne Le Nestour, Ronn Andriessen, Alain Demourgues, Manuel Gaudon, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut de Recherches sur les Archéomatériaux (IRAMAT), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM), Laboratoire catalyse et spectrochimie (LCS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), and Agfa-Gevaert
- Subjects
Absorption spectroscopy ,Annealing (metallurgy) ,Aluminate ,Inorganic chemistry ,Inorganic compounds ,chemistry.chemical_element ,02 engineering and technology ,Zinc ,engineering.material ,010402 general chemistry ,01 natural sciences ,Aluminate spinel ,Inorganic Chemistry ,Metal ,chemistry.chemical_compound ,Chemical structure ,Physical and Theoretical Chemistry ,Optical properties ,Spinel ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Copper ,0104 chemical sciences ,Crystallography ,chemistry ,visual_art ,visual_art.visual_art_medium ,engineering ,Crystallite ,0210 nano-technology - Abstract
Zn1-xCuxAl2O4 (0or = x0.30) compounds have been synthesized by polyesterification using metallic salts and annealing at low temperatures as well as by conventional solid state. XRD-powder data refinements (Rietveld method) have demonstrated that both compound series crystallize in the spinel structure (Fd3m) and exhibit similar inversion rates. This low-temperature route lead to metastable phases with crystallite sizes around 40 nm whereas particle sizes are larger than 1 moicrom in the case of solid-state route. This preparative method largely described in the literature allows stabilizing reduced copper states thanks to the presence of reductive organic species, which are decomposed below T = 700 degrees C. The absorption spectra of the x = 0.15 composition exhibit strong differences depending on the synthesis route. These differences can be explained by the occurrence of Cu2+/Cu+ mixed valencies in compounds prepared by the low-temperature route; 33% of monovalent copper has been identified in the x = 0.15 composition prepared by low-temperature process, whereas the solid-state compound contains only divalent copper. Reductive properties of polyesterification reaction implying citric acid and low annealing temperature (T = 700 degrees C) are mainly responsible of the occurrence of the Cu2+/Cu+ mixed valencies. Actually, the annealing under air at T = 1000 degrees C of divided zinc-copper aluminates prepared at low temperatures (T = 700 degrees C) leads to the oxidation reaction Cu+ --Cu2+ + e- confirmed by the evolution of magnetic measurements, ESR spectra, and optical absorption properties. Defects such as oxygen vacancies in the anionic network leading to reduction in the cations coordination number could also explain the strong evolution of optical absorption spectra especially around lambda = 700 nm where intervalencies transfer (Cu+/Cu2+) as well as intra-atomic d-d transitions (Cu2+ in a 5-fold coordination) can occur. Finally the occurrence of monovalent and divalent copper at the surface of such divided oxides, probably in tetrahedral sites, has been demonstrated by FTIR spectroscopy using the co-adsorption of CO and NO as probe molecules.
- Published
- 2007
13. TOF-SIMS investigation of degradation pathways occurring in a variety of organic photovoltaic devices: the ISOS-3 inter-laboratory collaboration
- Author
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Wouter Maes, Gerardo Teran-Escobar, Ronn Andriessen, Matthew T. Lloyd, Yulia Galagan, Gülsah Y. Uzunoglu, Agnès Rivaton, Monica Lira-Cantu, Dirk Vanderzande, Harald Hoppe, Eszter Voroshazi, Martin Hermenau, Mikkel Jørgensen, Morten Vesterager Madsen, Laurence Lutsen, Suren A. Gevorgyan, Uli Würfel, Eva Bundgaard, David S. Germack, Frederik C. Krebs, Birgitta Andreasen, Roland Rösch, Markus Hösel, Kion Norrman, Henrik Friis Dam, Birger Zimmernann, David M. Tanenbaum, Suleyman Kudret, Department of Chemistry, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Agfa-Gevaert, Fischereiforschungsstelle des Landes, Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Photochimie, Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-SIGMA Clermont (SIGMA Clermont)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-SIGMA Clermont (SIGMA Clermont)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Danish Council for Strategic Research, Danish Energy Agency, Danish National Research Foundation, European Commission, Consejo Nacional de Ciencia y Tecnología (México), Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, Federal Ministry of Education and Research (Germany), Thuringian Ministry of Education, Science and Culture, and America Scandinavia Foundation
- Subjects
polymer solar-cells, oxygen, mechanisms, stability, lifetimes, water ,Organic solar cell ,General Physics and Astronomy ,HOL - Holst ,Nanotechnology ,High Tech Systems & Materials ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,[CHIM]Chemical Sciences ,SDG 7 - Affordable and Clean Energy ,Electronics ,Physical and Theoretical Chemistry ,Inter-laboratory ,polymere Solarzellen, Sauerstoff, Stabilität, Flugzeit-Sekundärionen-Massenspektrometrie, TOF-SIMS, Wasser, Photovoltaik ,[PHYS]Physics [physics] ,TS - Technical Sciences ,Industrial Innovation ,business.industry ,Chemistry ,Photovoltaic system ,Mechatronics, Mechanics & Materials ,021001 nanoscience & nanotechnology ,Solar energy ,0104 chemical sciences ,Secondary ion mass spectrometry ,Physical Chemistry ,Atomic, Molecular & Chemical Physics ,ddc:540 ,0210 nano-technology ,business - Abstract
The present work is the fourth (and final) contribution to an inter-laboratory collaboration that was planned at the 3rd International Summit on Organic Photovoltaic Stability (ISOS-3). The collaboration involved six laboratories capable of producing seven distinct sets of OPV devices that were degraded under well-defined conditions in accordance with the ISOS-3 protocols. The degradation experiments lasted up to 1830 hours and involved more than 300 cells on more than 100 devices. The devices were analyzed and characterized at different points of their lifetimes by a large number of non-destructive and destructive techniques in order to identify specific degradation mechanisms responsible for the deterioration of the photovoltaic response. Work presented herein involves time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to study chemical degradation in-plane as well as in-depth in the organic solar cells. Various degradation mechanisms were investigated and correlated with cell performance. For example, photo-oxidation of the active material was quantitatively studied as a function of cell performance. The large variety of cell architectures used (some with and some without encapsulation) enabled valuable comparisons and important conclusions to be drawn on degradation behaviour. This comprehensive investigation of OPV stability has significantly advanced the understanding of degradation behaviour in OPV devices, which is an important step towards large scale application of organic solar cells. © 2012 the Owner Societies., This work has been supported by the Danish Strategic Research Council (2104-07-0022), EUDP (j.no. 64009-0050, 64009-0051) and the Danish National Research Foundation. Partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project HIFLEX (grant no. 248678), partial financial support from the EUIndian framework of the ‘‘Largecells’’ project that received funding from the European Commission’s Seventh Framework Programme (FP7/2007–2013. grant no. 261936), partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project ROTROT (grant no. 288565) and from PVERA-NET (project acronym POLYSTAR). are due to CONACYT (México) for the PhD scholarship awarded to G. T.-E; to the Spanish Ministry of Science and Innovation, MICINN-FEDER project ENE2008-04373; to the Consolider NANOSELECT project CSD2007-00041; to the Xarxa de Referència en Materials Avançats per a l’Energia, XaRMAE of the Catalonia Government (Spain). RR and HH are grateful for financial support from the Thuringian Ministry of Culture and the German Federal Ministry of Education and Research in the frameworks of FIPV II and PPP (contract number 13N9843), respectively. DMT acknowledges generous support from the Inger and Jens Bruun Foundation through The American-Scandinavian Foundation.
- Published
- 2012
14. On the stability of a variety of organic photovoltaic devices by IPCE and in-situ IPCE analyses - The ISOS-3 inter-laboratory collaboration
- Author
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Uli Würfel, Mikkel Jørgensen, Laurence Lutsen, Dirk Vanderzande, Suren A. Gevorgyan, Birger Zimmermann, Eva Bundgaard, Matthew T. Lloyd, Kion Norrman, Henrik Friis Dam, Martin Hermenau, Frederik C. Krebs, Roland Rösch, David S. Germack, Birgitta Andreasen, Suleyman Kudret, Gerardo Teran-Escobar, Ronn Andriessen, Monica Lira-Cantu, Gülsah Y. Uzunoglu, Harald Hoppe, Morten Vesterager Madsen, Eszter Voroshazi, Yulia Galagan, Agnès Rivaton, Markus Hösel, Wouter Maes, David M. Tanenbaum, Department of Chemistry, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Agfa-Gevaert, Fischereiforschungsstelle des Landes, Photochimie, Institut de Chimie de Clermont-Ferrand (ICCF), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Publica, Danish Council for Strategic Research, Danish National Research Foundation, European Commission, Consejo Nacional de Ciencia y Tecnología (México), Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, Federal Ministry of Education and Research (Germany), America Scandinavia Foundation, and Thuringian Ministry of Education, Science and Culture
- Subjects
In situ ,Materials science ,Hybrid-Solarzellen, Phthalocyanin, dünne Schichten, Zinkphthalocyanin, Oxid-Halbleiter, Feuchtigkeitssensor, Sauerstoff, Degradation, Zinkoxid, Nanoteilchen ,Organische Solarzellen ,General Physics and Astronomy ,HOL - Holst ,Nanotechnology ,High Tech Systems & Materials ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,law.invention ,Farbstoff ,PEDOT:PSS ,law ,Solar cell ,[CHIM]Chemical Sciences ,Electronics ,SDG 7 - Affordable and Clean Energy ,Physical and Theoretical Chemistry ,Solarzellen - Entwicklung und Charakterisierung ,[PHYS]Physics [physics] ,TS - Technical Sciences ,Industrial Innovation ,Moisture ,business.industry ,Photovoltaic system ,Energy conversion efficiency ,Alternative Photovoltaik-Technologien ,Mechatronics, Mechanics & Materials ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Solar Cells ,13. Climate action ,ddc:540 ,Farbstoff- und Organische Solarzellen ,Optoelectronics ,Degradation (geology) ,Organische und Neuartige Solarzellen ,Physical Chemistry ,Atomic, Molecular & Chemical Physics ,hybrid solar cells, phthalocyanine thin films, zinc phthalocyanine, semiconductor oxides, optical-properties, humidity sensors, oxygen, degradation, ZnO, zinc oxide, nanoparticles ,0210 nano-technology ,business ,Stability - Abstract
This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISO-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N 2) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO 3), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetime. © 2012 the Owner Societies., This work has been supported by the Danish Strategic Research Council (2104-07-0022), EUDP (j.no. 64009-0050), and the Danish National Research Foundation. Partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project HIFLEX (grant no. 248678), partial financial support from the EUIndian framework of the ‘‘Largecells’’ project that received funding from the European Commission’s Seventh Framework Programme (FP7/2007–2013. grant no. 261936), partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project ROTROT (grant no. 288565) and from PVERA-NET (project acronym POLYSTAR). To CONACYT (México) for the Ph.D. scholarship awarded to G. T.-E, to the Spanish Ministry of Science and Innovation, MICINN-FEDER project ENE2008-04373, to the Consolider NANOSELECT project CSD2007-00041, to the Xarxa de Referència en Materials Avançats per a l’Energia, XaRMAE of the Catalonia Government (Spain). RR and HH are grateful for financial support from the Thuringian Ministry of Culture and the German Federal Ministry of Education and Research in the frameworks of FIPV II and PPP (contract number 13N9843), respectively. DMT acknowledges generous support from the Inger and Jens Bruun Foundation through The American–Scandinavian Foundation.
- Published
- 2012
15. Investigation of the degradation mechanisms of a variety of organic photovoltaic devices by combination of imaging techniques: the ISOS-3 inter-laboratory collaboration
- Author
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Maik Bärenklau, Morten Vesterager Madsen, Ronn Andriessen, Yulia Galagan, David S. Germack, Birgitta Andreasen, Agnès Rivaton, Mikkel Jørgensen, Suren A. Gevorgyan, Wouter Maes, Marco Seeland, David M. Tanenbaum, Kion Norrman, Gerardo Teran-Escobar, Henrik Friis Dam, Birger Zimmermann, Markus Hösel, Dirk Vanderzande, Martin Hermenau, Laurence Lutsen, Matthew T. Lloyd, Suleyman Kudret, Frederik C. Krebs, Uli Würfel, Roland Rösch, Gülsah Y. Uzunoglu, Monica Lira-Cantu, Harald Hoppe, Eszter Voroshazi, Fischereiforschungsstelle des Landes, Department of Chemistry, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Agfa-Gevaert, Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Photochimie, Institut de Chimie de Clermont-Ferrand (ICCF), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Publica, Thuringian Ministry of Education, Science and Culture, Federal Ministry of Education and Research (Germany), Danish Council for Strategic Research, Danish National Research Foundation, European Commission, Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, America Scandinavia Foundation, and Consejo Nacional de Ciencia y Tecnología (México)
- Subjects
Engineering ,Organic solar cell ,HOL - Holst ,Nanotechnology ,High Tech Systems & Materials ,02 engineering and technology ,Electroluminescence ,010402 general chemistry ,01 natural sciences ,[CHIM]Chemical Sciences ,Environmental Chemistry ,SDG 7 - Affordable and Clean Energy ,Electronics ,[SDV.EE]Life Sciences [q-bio]/Ecology, environment ,TS - Technical Sciences ,Industrial Innovation ,Renewable Energy, Sustainability and the Environment ,business.industry ,Photovoltaic system ,Mechatronics, Mechanics & Materials ,021001 nanoscience & nanotechnology ,Solar energy ,Pollution ,0104 chemical sciences ,Variety (cybernetics) ,Nuclear Energy and Engineering ,Multidisciplinary Chemistry ,Energy & Fuels ,Chemical Engineering ,Environmental Sciences ,Polymer solar-cells ,Efficiency ,Stability ,Thermography ,Optoelectronics ,Degradation (geology) ,0210 nano-technology ,business - Abstract
The investigation of degradation of seven distinct sets (with a number of individual cells of n ≥ 12) of state of the art organic photovoltaic devices prepared by leading research laboratories with a combination of imaging methods is reported. All devices have been shipped to and degraded at Risø DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. Imaging of device function at different stages of degradation was performed by laser-beam induced current (LBIC) scanning; luminescence imaging, specifically photoluminescence (PLI) and electroluminescence (ELI); as well as by lock-in thermography (LIT). Each of the imaging techniques exhibits its specific advantages with respect to sensing certain degradation features, which will be compared and discussed here in detail. As a consequence, a combination of several imaging techniques yields very conclusive information about the degradation processes controlling device function. The large variety of device architectures in turn enables valuable progress in the proper interpretation of imaging results - hence revealing the benefits of this large scale cooperation in making a step forward in the understanding of organic solar cell aging and its interpretation by state-of-the-art imaging methods. This journal is © 2012 The Royal Society of Chemistry., RR, MS, MB and HH are grateful for financial support from the Thuringian Ministry of Culture and the German Federal Ministry of Education and Research in the frameworks of FIPV II and PPP (contract number 13N9843), respectively. This work has been supported by the Danish Strategic Research Council (2104-07-0022), EUDP (j.no. 64009-0050) and the Danish National Research Foundation. Partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project HIFLEX (grant no. 248678), partial financial support from the EUIndian framework of the ‘‘Largecells’’ project that received funding from the European Commission’s Seventh Framework Programme (FP7/2007–2013. grant no. 261936), partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project ROTROT (grant no. 288565) and from PVERA-NET (project acronym POLYSTAR). To the Spanish Ministry of Science and Innovation, MICINN-FEDER project ENE2008-04373, to the Consolider NANOSELECT project CSD2007-00041, to the Xarxa de Refer encia en Materials Avanc¸ats per a l’Energia, XaRMAE of the Catalonia Government (Spain). To CONACYT (M exico) for the PhD scholarship awarded to GT-E. DMT acknowledges support from the Inger and Jens Bruun Foundation through The American–Scandinavian Foundation.
- Published
- 2012
16. The ISOS-3 inter-laboratory collaboration focused on the stability of a variety of organic photovoltaic devices
- Author
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Morten Vesterager Madsen, David S. Germack, Birgitta Andreasen, Roland Rösch, Ronn Andriessen, Yulia Galagan, David M. Tanenbaum, Uli Würfel, Gülsah Y. Uzunoglu, Dirk Vanderzande, Martin Hermenau, Birger Zimmermann, Laurence Lutsen, Agnès Rivaton, Kion Norrman, Henrik Friis Dam, Markus Hösel, Monica Lira-Cantu, Harald Hoppe, Eszter Voroshazi, Mikkel Jørgensen, Frederik C. Krebs, Wouter Maes, Matthew T. Lloyd, Suleyman Kudret, Gerardo Teran-Escobar, Suren A. Gevorgyan, Danish Council for Strategic Research, European Commission, Photochimie, Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie du CNRS (INC)-SIGMA Clermont (SIGMA Clermont)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-SIGMA Clermont (SIGMA Clermont)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Agfa-Gevaert, Fischereiforschungsstelle des Landes, Bonnefoy, Stéphanie, Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Publica
- Subjects
Organische Solarzellen ,General Chemical Engineering ,HOL - Holst ,Nanotechnology ,High Tech Systems & Materials ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Farbstoff ,SDG 7 - Affordable and Clean Energy ,Electronics ,Inter-laboratory ,Farbstoff und Organische Solarzellen ,Solarzellen - Entwicklung und Charakterisierung ,TS - Technical Sciences ,Industrial Innovation ,Solar-cells ,business.industry ,Photovoltaic system ,Alternative Photovoltaik-Technologien ,General Chemistry ,Mechatronics, Mechanics & Materials ,021001 nanoscience & nanotechnology ,Solar energy ,Engineering physics ,Solar Cells ,0104 chemical sciences ,Chemistry ,Organische und Neuartige Solarzellen ,0210 nano-technology ,business ,Stability - Abstract
Seven distinct sets (n ≥ 12) of state of the art organic photovoltaic devices were prepared by leading research laboratories in a collaboration planned at the Third International Summit on Organic Photovoltaic Stability (ISOS-3). All devices were shipped to RISØ DTU and characterized simultaneously up to 1830 h in accordance with established ISOS-3 protocols under three distinct illumination conditions: accelerated full sun simulation; low level indoor fluorescent lighting; and dark storage with daily measurement under full sun simulation. Three nominally identical devices were used in each experiment both to provide an assessment of the homogeneity of the samples and to distribute samples for a variety of post soaking analytical measurements at six distinct laboratories enabling comparison at various stages in the degradation of the devices. Over 100 devices with more than 300 cells were used in the study. We present here design and fabrication details for the seven device sets, benefits and challenges associated with the unprecedented size of the collaboration, characterization protocols, and results both on individual device stability and uniformity of device sets, in the three illumination conditions. © 2012 The Royal Society of Chemistry., This work has been supported by the Danish Strategic Research Council (2104-07-0022), EUDP (j.no. 64009-0050) and the Danish National Research Foundation. Partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project HIFLEX (grant no. 248678), partial financial support from the EUIndian framework of the ‘‘Largecells’’ project that received funding from the European Commission’s Seventh Framework Programme (FP7/2007–2013. grant no. 261936), partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project ROTROT (grant no. 288565) and from PVERA-NET (project acronym POLYSTAR).
- Published
- 2012
17. Switchable hydrophobic-hydrophilic layer obtained onto porous alumina by plasma-enhanced fluorination
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E. Durand, A. Tressaud, C. Brigouleix, H. Andriessen, C. Labrugère, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), and Agfa-Gevaert
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Materials science ,Porous alumina ,Hydrophobic-hydrophilic ,02 engineering and technology ,Substrate (printing) ,engineering.material ,010402 general chemistry ,01 natural sciences ,Switchable layer ,Contact angle ,Offset applications ,Coating ,X-ray photoelectron spectroscopy ,XPS ,Organic chemistry ,Surface layer ,Porosity ,Lithography ,rf-plasma fluorination ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemical engineering ,engineering ,0210 nano-technology ,Layer (electronics) - Abstract
International audience; Conventional lithographic printing processes using porous alumina for offset applications generally use “wet” routes. Recently “dry” processes have been developed which are based on a heat-induced hydrophilic/oleophilic conversion of one or more layers of the coating so that a stronger affinity to-wards ink or water fountain is created at the exposed areas with respect to the surface of the unex-posed coating. Treatments involving rf plasma-enhanced fluorination (PEF) constitute exceptional tools for modifying the surface properties of materials. Many advantages of these techniques can be indeed outlined, when compared to more conventional methods: room-temperature reactions, chemical modi-fications limited to surface only without changing the bulk properties, possible non-equilibrium reac-tions. The influence of PEF treatments on porous alumina layer used in printing plates has been tested with various fluorinated gases (CF4, C3F8 and C4F8) and characterized by XPS. The hydrophobic prop-erties of the fluorinated layer have been deduced from contact angle measurements. Using C4F8 rf-PEF treatment, the outmost surface of the hydrophilic alumina substrate used for lithographic printing is hydrophobized, or in other words, the hydrophilic substrate is converted into a support with hydro-phobic properties. Once being hydrophobized, the surface layer may be rendered hydrophilic using a heat pulse, thus giving rise to switchable hydrophobic-hydrophilic properties of the material.
- Published
- 2009
18. Steric and electronic effects relating to the Cu2+ Jahn-Teller Distortion in Zn1-xCuxAl2O4 spinels
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A. Le Nestour, Gérard Villeneuve, Alain Demourgues, Ronn Andriessen, Manuel Gaudon, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut de Recherches sur les Archéomatériaux (IRAMAT), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS), and Agfa-Gevaert
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Steric effects ,Solid solution ,Jahn-Teller effect ,Jahn–Teller effect ,Spinel ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,Ion ,Inorganic Chemistry ,Computational chemistry ,Electronic effect ,Physical and Theoretical Chemistry ,Colors ,Chemistry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Copper ,0104 chemical sciences ,Crystallography ,Octahedron ,engineering ,0210 nano-technology - Abstract
Zn1-xCuxAl2O4 (0or= xor= 1) compositions have been synthesized by solid-state route, and a color scale going from white (x = 0) to brownish-red (x = 1) with intermediate colors as pale green for x = 0.10 and pale brown for x = 0.30 can be observed. XRD-data refinements on the whole solid solution have allowed defining two critical areas where structural features such as cell parameter and inversion rate as well as cation-oxygen bond distances in 8a and 16d sites of the spinel network exhibit clear unique variations. By observing the direct environment of tetrahedral and octahedral sites potentially occupied by Cu2+ Jahn-Teller cations, the two critical compositions have been estimated to x1 =1/6 and x2 = 4/7. Actually from the x1 and x2 copper contents, the probability of getting Cu2+-Cu2+ pairs involving tetrahedral-octahedral or two octahedral sites respectively is high. Then, the stabilization of Cu2+ JT ions in distorted octahedral site, identified by ESR, is in competition with the occurrence of Cu2+ in tetrahedral sites, and both electronic and steric effects of Cu2+ JT cations lead to the explanation of the evolution of the inversion rate in this series. The study of the optical absorption properties clearly shows that the position and the intensity of the various absorption bands are influenced by the distribution of Cu2+ ions in tetrahedral and octahedral sites, the creation of Cu2+-Cu2+ pairs around the x1 and x2 critical compositions, and the increasing of Cu-O bond covalency. Such an evolution of structural features correlated with electronic properties where various critical compositions have been identified can be generalized to other spinel oxides, considering local distortion around Jahn-Teller ions.
- Published
- 2007
19. Photoluminescence of Eu2+ in BaF2-rich fluorohalides and photostimulation after X-ray irradiation
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L Struye, A. Moudden, Claude Fouassier, P Willems, Alain Garcia, B. Es-Sakhi, P. J. R. Leblans, Université Ibn Zhor, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), and Agfa-Gevaert
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Photoluminescence ,Materials science ,Photostimulated luminescence ,Analytical chemistry ,chemistry.chemical_element ,Quantum yield ,Phosphor ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,01 natural sciences ,Storage phosphors ,Eu2+-doped barium chlorofluoride ,General Materials Science ,Irradiation ,Bromine ,Mechanical Engineering ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,3. Good health ,chemistry ,Mechanics of Materials ,Photostimulation ,0210 nano-technology ,Luminescence ,Nuclear chemistry - Abstract
The luminescence of Eu 2+ has been investigated in two families of BaF 2 -rich fluorohalides, Ba 12 Cl 5(1− x ) Br 5 x F 19 ( x ≤0.8) and Ba 7 Cl 2(1− x ) Br 2 x F 12 ( x ≤0.5). In the two kinds of host lattices, under UV excitation Eu 2+ shows an intense blue 5d→4f band emission at 300 K. At low temperature, in addition to the latter, 4f→4f lines are present in the near UV. The efficiency of the photostimulated luminescence (PSL) after X-ray irradiation has been measured and compared with that of BaXF:Eu (X=Cl, Br). High conversion efficiencies have been obtained with compositions Ba 12 Cl 5(1− x ) Br 5 x F 19 for stimulation at 532 nm. The presence of bromine is beneficial. For all compositions a high stimulation energy (SE) is needed to excite Eu 2+ ions through colour centres.
- Published
- 2003
20. Phase-engineering compact and flexible CsPbBr 3 microcrystal films for robust X-ray detection.
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Clinckemalie L, Pradhan B, Brande RV, Zhang H, Vandenwijngaerden J, Saha RA, Romolini G, Sun L, Vandenbroucke D, Bonn M, Wang HI, and Debroye E
- Abstract
All-inorganic CsPbBr
3 perovskites have gained significant attention due to their potential in direct X-ray detection. The fabrication of stable, pinhole-free thick films remains challenging, hindering their integration in durable, large-area high-resolution devices. In this study, we propose a facile strategy using a non-conductive polymer to create a flexible, compact thick film under ambient conditions. Furthermore, we investigate the effect of introducing the 2D CsPb2 Br5 phase into CsPbBr3 perovskite crystals on their photophysical properties and charge transport. Upon X-ray exposure, the devices consisting of the dual phase exhibit improved stability and more effective operation at higher voltages. Rietveld refinement shows that, due to the presence of the second phase, local distortions and Pb-vacancies are introduced within the CsPbBr3 lattice. This in turn presumably increases the ion migration energy barrier, resulting in a very low dark current and hence, enhanced stability. This feature might benefit local charge extraction and, ultimately, the X-ray image resolution. These findings also suggest that introducing a second phase in the perovskite structure can be advantageous for efficient photon-to-charge carrier conversion, as applied in medical imaging., Competing Interests: The authors declare no competing financial interests., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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21. Continuous generation of cross-linked polymer nanoparticles employing an ultrasonic microreactor.
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Udepurkar AP, Dermaut W, Clasen C, and Kuhn S
- Abstract
In this article, a new system employing an ultrasonic microreactor coupled with a tubular reactor is presented for the continuous generation of polymer nanoparticles. The continuous generation of cross-linked polymer nanoparticles utilizing the monomer butyl methacrylate and the cross-linker ethylene glycol dimethacrylate is demonstrated. Firstly, the miniemulsion polymerization of a monomer-in-water miniemulsion is studied in a batch system. Secondly, a coiled tubular reactor is employed for the continuous polymerization of the miniemulsion generated by an ultrasonic microreactor. Finally, the influence of monomer volume fraction and surfactant concentration on the synthesized polymer nanoparticles is studied. Polymer particles in a size range of 50-250 nm are synthesized and a high polymerization conversion is achieved utilizing the system demonstrated in this article., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)
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- 2023
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22. Seven general radiography x-ray detectors with pixel sizes ranging from 175 to 76 μ m: technical evaluation with the focus on orthopaedic imaging.
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Marshall NW, Vandenbroucke D, Cockmartin L, Wanninger F, Smet M, Feng Y, Ni Y, and Bosmans H
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- Animals, Rabbits, X-Rays, Radiography, Azo Compounds, Orthopedics
- Abstract
Aim . Flat panel detectors with small pixel sizes general can potentially improve imaging performance in radiography applications requiring fine detail resolution. This study evaluated the imaging performance of seven detectors, covering a wide range of pixel sizes, in the frame of orthopaedic applications. Material and methods . Pixel sizes ranged from 175 (detector A
175 ) to 76 μ m (detector G76 ). Modulation transfer function (MTF) and detective quantum efficiency (DQE) were measured using International Electrotechnical Commission (IEC) RQA3 beam quality. Threshold contrast ( CT ) and a detectability index ( d ') were measured at three air kerma/image levels. Rabbit shoulder images acquired at 60 kV, over five air kerma levels, were evaluated in a visual grading study for anatomical sharpness, image noise and overall diagnostic image quality by four radiologists. The detectors were compared to detector E124 . Results . The 10% point of the MTF ranged from 3.21 to 4.80 mm-1 , in going from detector A175 to detector G76 . DQE(0.5 mm-1 ) measured at 2.38 μ Gy/image was 0.50 ± 0.05 for six detectors, but was higher for F100 at 0.62. High frequency DQE was superior for the smaller pixel detectors, however CT for 0.25 mm discs correlated best with DQE(0.5 mm-1 ). Correlation between CT and the detectability model was good ( R2 = 0.964). CT for 0.25 mm diameter discs was significantly higher for D150 and F100 compared to E124 . The visual grading data revealed higher image quality ratings for detectors D125 and F100 compared to E124 . An increase in air kerma was associated with improved perceived sharpness and overall quality score, independent of detector. Detectors B150 , D125 , F100 and G76 , performed well in specific tests, however only F100 consistently outperformed the reference detector. Conclusion . Pixel size alone was not a reliable predictor of small detail detectability or even perceived sharpness in a visual grading analysis study., (© 2023 Institute of Physics and Engineering in Medicine.)- Published
- 2023
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23. Advances in multiscale image processing and its effects on image quality in skeletal radiography.
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Notohamiprodjo S, Roeper KM, Mueck FG, Maxien D, Wanninger F, Hoberg B, Verstreepen L, Treitl KM, Fischer F, Peschel O, and Wirth S
- Subjects
- Radiation Dosage, Radiography, Bone and Bones diagnostic imaging, Image Processing, Computer-Assisted methods
- Abstract
Multi-frequency processing (MFP) leads to enhanced image quality (IQ) of radiographs. This study is to determine the effect of third generation MFP (M3) on IQ in comparison to standard second-generation MFP (M2). 20 cadavers were examined and post-processing of radiographs was performed with both M2 and M3. Three readers blinded to the MFP used for each image independently compared corresponding image pairs according to overall IQ and depiction of bony structures and soft tissue (+ 2: notably better > 0: equal > - 2: notably worse). A significant deviation of the median grade from grade 0 (equal) (p < 0.01) for each evaluator A, B and C speaks against an equal image quality of M2- and M3-images. M3-images were categorized with better grades (+ 1, + 2) in 87.7% for overall image quality, in 90.4% for soft tissue and 81.8% for bony structures. M3 images showed significant higher averaged SNR and CNR for all investigated lower extremities than that of M2 images (0.031 < p < 0.049). The newest generation of MFP leads to significantly better depiction of anatomical structures and overall image quality than in images processed with the preceding generation of MFP. This provides increased diagnostic accuracy and further decreased radiation exposure., (© 2022. The Author(s).)
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- 2022
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24. Image quality is resilient against tube voltage variations in post-mortem skeletal radiography with a digital flat-panel detector.
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Notohamiprodjo S, Roeper KM, Treitl KM, Hoberg B, Wanninger F, Verstreepen L, Mueck FG, Maxien D, Fischer F, Peschel O, and Wirth S
- Abstract
In recent phantom studies low-contrast detectability was shown to be independent from variations in tube voltage in digital radiography (DR) systems. To investigate the transferability to a clinical setting, the lower extremities of human cadavers were exposed at constant detector doses with different tube voltages in a certain range, as proposed in the phantom studies. Three radiologists independently graded different aspects of image quality (IQ) in a comparative analysis. The grades show no correlation between IQ and kV, which means that the readers were not able to recognize a significant IQ difference at different kV. Signal-to-noise and contrast-to-noise ratios showed no significant differences in IQ despite the kV-setting variations. These findings were observed from a limited kV range setting. Higher kV-settings resulted in lowest patient exposure at constant IQ. These results confirm the potential of DR-systems to contribute to standardization of examination protocols comparable to computed tomography. This may prevent the trend to overexpose. Further investigations in other body regions and other DR-systems are encouraged to determine transferability.
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- 2021
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25. Dose reduction in mammography by using imaging plate technology: A retrospective analysis.
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Hittinger M, Mueck F, Wirth S, Hoberg B, Wanninger F, and Wallner CP
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- Adult, Aged, Aged, 80 and over, Breast diagnostic imaging, Female, Humans, Middle Aged, Retrospective Studies, X-Ray Intensifying Screens, Breast Neoplasms diagnostic imaging, Mammography methods, Radiation Dosage, Radiographic Image Enhancement methods
- Abstract
Purpose: Conventional mammography is a decisive tool in detecting breast cancer. Continuous efforts are undertaken in order to further improve the image quality as well as to reduce the applied doses. The purpose of our study was to compare diagnostic image quality of dose reduced computed mammography with a new needle-based detector system to full dose powder imaging plates., Methods: We retrospectively compared 360 randomly chosen mammographies performed on a GE Senographe DMR running the Agfa DX-M needle-based imaging plate system (NIP) with their preliminary examinations which were acquired at standard dose with the same GE mammography device and an Agfa CR85-X powdered storage phosphor imaging plate system (PIP). NIP-based mammographies were about 29.8 % dose-reduced. The preliminary examinations had to be performed not earlier than 2 years before the recent investigations. Exclusion criteria were changes in ACR level and appearance of the scored targets and not optimally positioned and exposed mammographies. The images were blinded and read separately twice by 2 mammography experts according to a 3-point score on diagnostic image quality and the visualization of parenchyma, cysts, fibroadenomas, physiologic lymph nodes, solitary microcalcifications and macrocalcifications., Results: Dose reduced NIPs showed a significantly better visualization of parenchyma at ACR II/III and solitary microcalcifications at ACR I-III mammographies (p < 0.001) whereas the difference in scoring macrocalcifications, cysts, fibroadenomas and physiologic lymph nodes was not significant. The reading showed an excellent intra- (r = 0.97/0.94) and interobserver agreement (r = 0.92)., Conclusion: With computed mammography using the needle-based detector system a significant dose reduction is possible without loss of diagnostic image quality., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
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26. Digital chest tomosynthesis: the 2017 updated review of an emerging application.
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Ferrari A, Bertolaccini L, Solli P, Di Salvia PO, and Scaradozzi D
- Abstract
Lung cancer is the leading cause of cancer death and second most common cancer among both men and women, but most of them are detected when patients become symptomatic and in late-stage. Chest radiography (CR) is a basic technique for the investigation of lung cancer and has the benefit of convenience and low radiation dose, but detection of malignancy is often difficult. The introduction of computed tomography (CT) for screening has increased the proportion of lung cancer detected but with higher exposure dose and higher costs. Digital chest tomosynthesis (DCT), a tomographic technique, may offer an alternative to CT. DCT uses a conventional radiograph tube, a flat-panel detector, a computer-controlled tube mover and reconstruction algorithms to produce section images. It shows promise in the detection of potentially malignant lung nodules, with higher sensibility than CR, and is emerging as a low-dose and low-cost alternative to CT to improve treatment decisions. In fact, an increasing number of researchers are showing that tomosynthesis could have a role in the detection of lung cancer, in addition to its present role in breast screening. However, DCT offers some limitations, such as limited depth resolution, which may explain the difficulty in detecting pathologies in the subpleural region and the occurrence of artefacts from medical devices. Once solved these limitations and once more studies supporting its use will be available, DCT could become the first-line lung cancer screening tool among patients at considerable risk of lung cancer., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
- Published
- 2018
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27. Prediction of Vibronic Coupling and Absorption Spectra of Dimers from Time-Dependent Density Functional Theory: The Case of a Stacked Streptocyanine.
- Author
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Guthmuller J, Zutterman F, and Champagne B
- Abstract
Methods based on density functional theory calculations have been used to simulate the absorption spectra of a streptocyanine and of its covalently bonded dimer. Two approaches, based on multimode Franck-Condon overlap integrals, have been employed. In the first approach the monomer and the dimer are treated as single molecules, and the Franck-Condon factors are determined for both systems. The second approach is based on the diagonalization of the dimer Hamiltonian which is constructed from the monomer Franck-Condon overlap integrals and quantities describing the intermonomer electronic coupling. Both approaches succeed in reproducing the hypsochromic shift of the maximum of absorption occurring upon dimerization with an accuracy of 0.05 eV. The vibronic structure of the monomer is also in good agreement with experiment and depends little on the inclusion of Duschinsky rotation effects. The shape and relative intensity of the dimer spectrum is qualitatively reproduced by the two methods, each of them being able to describe most of the vibronic features. Moreover, accounting for the solvent effects in the calculation of the intermonomer electronic coupling improves the agreement with experiment by reducing the intensity of the maximum and by enlarging the spectrum at longer wavelengths.
- Published
- 2008
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28. Steric and electronic effects relating to the Cu2+ Jahn-Teller distortion in Zn(1-)xCuxAl2O4 spinels.
- Author
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Le Nestour A, Gaudon M, Villeneuve G, Andriessen R, and Demourgues A
- Abstract
Zn1-xCuxAl2O4 (0
- Published
- 2007
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29. [New computed radiography technologies in digital radiography].
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Fasbender R and Schaetzing R
- Subjects
- Artifacts, Efficiency, Equipment Design, Humans, Luminescent Measurements, Phantoms, Imaging, Sensitivity and Specificity, Radiographic Image Enhancement instrumentation, Radiographic Image Interpretation, Computer-Assisted instrumentation, Technology, Radiologic instrumentation, X-Ray Intensifying Screens
- Abstract
Digital radiography (DR) has become integral to modern diagnostic radiology. One of the earliest forms of DR, computed radiography (CR) using storage phosphors, has established itself as the mainstay of DR-based diagnostic imaging over the past 20 years. More recently, flat-panel DR systems based on solid state X-ray detectors with integrated, large-area, active-matrix readout electronics are promising further improvements in clinical workflow and image quality. Despite CR's longevity, innovations continue to be made. New developments in CR screen technologies, like structured (needle) screens, and new scanner concepts based on line-at-a-time reading promise major improvements in image quality (comparable to that of flat-panel systems), system through-put and physical size, at a cost comparable to that of today's systems. Thus, despite the advent of flat-panel acquisition systems, there will still be an important role for CR in the foreseeable future. After a brief review of the current state of CR technology, this paper will explore several of these new CR developments and present some examples of their potential clinical impact.
- Published
- 2003
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30. A new needle-crystalline computed radiography detector.
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Leblans P, Struye L, and Willems P
- Subjects
- Computer Storage Devices, Equipment Design, Humans, Technology, Radiologic, X-Ray Intensifying Screens, Radiographic Image Enhancement instrumentation, Tomography, X-Ray Computed instrumentation
- Abstract
The most successful digital radiography detectors to date have been storage phosphor plates used in computed radiography (CR). The detector is cheap, has good producibility, and is robust. Direct radiography (DR) systems are being developed based on flat-panel technology. Better image quality is claimed for some DR systems. On the other hand, DR detectors have low producibility and robustness, and a high price. A new CR detector is being developed at Agfa that combines the advantages of CR and DR. It is a storage phosphor plate made up of needle-shaped crystals. The phosphor efficiently converts absorbed x-ray quanta into photostimulable centers for efficient read out. It has a large dynamic range and its emission is efficiently detected with both photomultiplier tube (PMT) and charge coupled device (CCD). It is shown that CR systems based on the new detector offer image quality that matches that of the best DR systems.
- Published
- 2000
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31. Filmless cardiac imaging: motion or commotion?
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Vastenaeken GD
- Subjects
- Cineangiography, Computer Storage Devices, Coronary Angiography economics, Coronary Angiography trends, Cost-Benefit Analysis, Humans, Radiology Information Systems economics, Radiology Information Systems trends, Reproducibility of Results, X-Ray Film, Coronary Angiography methods, Radiographic Image Enhancement economics, Radiographic Image Enhancement methods, Radiographic Image Enhancement trends
- Abstract
At present times the medical cardiology imaging is still arguing about the usefulness of X-Ray Cine film in comparison with digital and filmless imaging. It is clear that both techniques have their advantages. X-Ray Cine film is a well established technique of which the possibilities are well known. At a first glance filmless imaging offers nothing but advantages. However the whole picture becomes clear when trying to implement these systems in a clinical environment, because at that time aspects of investments, technological continuity and risks, needed skills and effects on the workflow appear. This article has the purpose to clarify some of these aspects and give guidance in the difficult process of making the right decision.
- Published
- 1998
- Full Text
- View/download PDF
32. Digital imaging: the Agfa experience.
- Author
-
Anrijs H
- Subjects
- Humans, Image Enhancement instrumentation, Image Enhancement methods, Image Enhancement standards, Radiology Information Systems, Technology, Radiologic, Diagnostic Imaging instrumentation, Diagnostic Imaging methods, Diagnostic Imaging standards, Image Processing, Computer-Assisted instrumentation, Image Processing, Computer-Assisted methods, Image Processing, Computer-Assisted standards
- Published
- 1997
33. MIRIAM: the PACS project in Paris: overview and implementation.
- Author
-
Primo H and Picard JE
- Subjects
- Computer Communication Networks, Diagnostic Imaging, Humans, Paris, Radiology Information Systems
- Abstract
In this article the authors describe the Management Informatique de la Radiologie et de l'Imagerie Médicale (MIRIAM) major picture archiving and communication system (PACS) project in Paris, France. The Assistance Publique of Paris, France is a healthcare provider and took the initiative to start the largest PACS program in Europe to date. The MIRIAM project will start in 1997 and will be used in different, consecutive phases. A consortium of several companies is in charge of the implementation. Thirty-three hospitals with 54 imaging departments will be integrated in one system.
- Published
- 1997
- Full Text
- View/download PDF
34. Replacing cinefilm: motion or commotion?
- Author
-
Aerts LM
- Subjects
- Cardiology, Compact Disks, Humans, Radiology Information Systems, Cardiac Catheterization, Image Processing, Computer-Assisted, Information Systems
- Abstract
Digital techniques are well established in the world of cardiac imaging. The catheterization laboratory has become a compilation of independent digitized systems. There is a broad choice of alternatives for cinefilm, but a lot of questions remain unanswered. The last two years, some breakthroughs have been realized: the acceptance of DICOM and CD-R has opened new perspectives. Considering the different user requirements, however, it remains very difficult to actually find an ideal solution. Therefore, the best investments for the coming two to three years remains a hybrid solution: digital modalities for acquisition and reviewing, and 35 mm cinefilm for archiving and communication.
- Published
- 1995
- Full Text
- View/download PDF
35. [Signal-to-noise ratio or the number of perceptible grey tones in the x-ray picture. II: Information content and viewing conditions].
- Author
-
Blendl C, Kierdorf M, Bollen R, and Freytag KH
- Subjects
- Technology, Radiologic, Radiography
- Abstract
The information obtainable from a radiograph depends on the viewing conditions under which the radiograph is viewed. All the viewing conditions can be defined in terms of scattered light. The amount of information taken from a radiograph with S = 1000 (S = speed class) and perfect conditions is the same as that from a radiography with S = 100 viewed under poor conditions. The optimum illuminance for the radiograph viewing room is 50 lx diffuse. The influence of scattered light is small enough to cause only a small loss of information. With the illuminance of 50 lx diffuse in the viewing room and Lo = 2000 cd/m2, the density range should be delta D = 2.85. The scattered light reduces it to delta D = 2.60 when the radiograph is viewed under the above-mentioned circumstances.
- Published
- 1993
36. [Signal to noise ratio or the number of perceptible gray tones in the x-ray picture. I. The dependence on the system sensitivity S (DIN 6867)].
- Author
-
Blendl C, Kierdorf M, Bollen R, and Freytag KH
- Subjects
- Germany, Humans, Sensitivity and Specificity, Radiography standards, X-Ray Intensifying Screens
- Abstract
It is shown that the number of contrasts which can be differentiated on a radiograph depends on the detail size, the noise, and the viewing conditions. The minimum signal-to-noise ratio (SNR) for a perception approach is equivalently described by the SGA value. This testing method was first developed by De Belder and Bollen to examine the visibility of low contrast details. The correlation between the SGA and the speed class S of the system can be explained by this method.
- Published
- 1993
37. [The influence of the spectrum and the type of exposure on the contrast of double-sided coated x-ray film].
- Author
-
Blendl C, Bollen R, and Freytag KH
- Subjects
- Lighting, Spectrometry, X-Ray Emission, Technology, Radiologic, X-Ray Film standards
- Abstract
The present article describes the circumstances concerning the use of testing aids such as sensitometers with one-sided exposure. It is shown which phenomena must be considered if radiographic films coated on both sides are exposed with a) standard pocket sensitometers (one-sided exposure), b) lab sensitometers (double-sided exposure to ANSI Ph 2.9 [1964]), c) x-radiation in the cassette, intensifying screen and film system (to DIN 6867 T 1). The effect of the emission spectrum on the resulting contrast factor is described. The importance of different emulsion technologies (e.g. orthochromatic anticross-over films) for the contrast factor with one-sided exposure is described. The cross-over factor (c.o.), the apparent variation in sensitivity of the front and back emulsion with one-sided exposure, is the cause of the reduction in the contrast factor (G average) as against double-sided exposure: delta G(%) = c.o.2 x 10(3)/8.4
- Published
- 1992
38. [The mean optical density in x-ray pictures: measurement methodology, results and parameters].
- Author
-
Blendl C and Kierdorf M
- Subjects
- Humans, Quality Assurance, Health Care, Radiography standards
- Abstract
A simple testing method for defining the average density or the integral density of x-ray images is described. In a semiquantitative way the physicians in radiological offices can measure the proper integral density. The amount of scattered x-rays influences the integral density significantly. Proper values for testing the integral density of x-ray images are described.
- Published
- 1992
39. Automated sampling and analysis in research product synthesis.
- Author
-
Timmermans L, den Bergh AV, Verhecken A, and de Sande CV
- Abstract
The information obtained about relevant reaction parameters can be greatly increased by monitoring concentration changes during a reaction. To achieve this goal, a fully automated system was designed which handles both sampling and analysis. The sampling system takes samples at predefined intervals, and also performs a number of tasks such as dilution, neutralization, filtration and analysis.The examples show the universal applicability of the device regarding to solvents, reaction media and reaction type. It is also demonstrated that the information, included in the concentration profiles, greatly increases our knowledge about the reaction. This increase in information, in conjunction with other data,for example calorimetry, could be used for reaction simulation software.
- Published
- 1992
- Full Text
- View/download PDF
40. Industry re-shaping of diagnostic imaging--the next decade.
- Author
-
Mountford G
- Subjects
- Equipment and Supplies, Hospital trends, Humans, Radiographic Image Enhancement trends, Diagnostic Imaging trends
- Published
- 1991
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