Littérature scientifique sur le sujet « Mixed organic layers »
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Articles de revues sur le sujet "Mixed organic layers"
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Rasoga, Oana, Anne Lutgarde Djoumessi Yonkeu, Carmen Breazu, Marcela Socol, Nicoleta Preda, Florin Stanculescu, Anca Stanculescu et Emmanuel Iwuoha. « Organic Heterostructures with Dendrimer Based Mixed Layer for Electronic Applications ». Molecules 29, no 17 (1 septembre 2024) : 4155. http://dx.doi.org/10.3390/molecules29174155.
Texte intégralRésumé :
Recently, much research has focused on the search for new mixed donor–acceptor layers for applications in organic electronics. Organic heterostructures with layers based on the generation 1 poly(propylene thiophenoimine) (G1PPT) dendrimer, N,N′-diisopropylnaphthalene diimide (MNDI), and a combination of the two were prepared and their electrical properties were investigated. Single layers of G1PPT and MNDI and a mixed layer (G1PPT:MNDI) were obtained via spin coating on quartz glass, silicon, and glass/ITO substrates, using chloroform as a solvent. The absorption mechanism was investigated, the degree of disorder was estimated, and the emission properties of the layers were highlighted using spectroscopic methods (UV–Vis transmission and photoluminescence). The effects of the concentration and surface topographical particularities on the properties of the layers were analyzed via atomic force microscopy. All of the heterostructures realized with ITO and Au electrodes showed good conduction, with currents of the order of mA. Additionally, the heterostructure with a mixed layer exhibited asymmetry in the current–voltage curve between forward and reverse polarization in the lower range of the applied voltages, which was more significant at increased concentrations and could be correlated with rectifier diode behavior. Consequently, the mixed-layer generation 1 poly(propylene thiophenoimine) dendrimer with N,N′-diisopropylnaphthalene diimide can be considered promising for electronic applications.
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Ghotsa Mekontchou, Claudele, Daniel Houle, Yves Bergeron et Igor Drobyshev. « Contrasting Root System Structure and Belowground Interactions between Black Spruce (Picea mariana (Mill.) B.S.P) and Trembling Aspen (Populus tremuloides Michx) in Boreal Mixedwoods of Eastern Canada ». Forests 11, no 2 (21 janvier 2020) : 127. http://dx.doi.org/10.3390/f11020127.
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This study explored the underground interactions between black spruce and trembling aspen in pure and mixed stands to understand how their soil resource use help these species coexist in the boreal mixedwoods of Western Quebec. We analyzed species-specific fine root foraging strategies (root biomass and root tissue density) along three soil layers (organic, top 0–15 cm, and bottom 15–30 cm mineral soil), using 180 soil cores. We collected cores in three sites, each containing three 20 × 50 m2 plots of pure spruce, pure aspen, and mixed spruce and aspen stands. Spruce had a shallow rooting, whereas aspen had a deep rooting in both types of stands. Compared to pure spruce stands, spruce had a lower fine root biomass (FRB) and a higher root tissue density (RTD) in the organic layer of mixed stands. Both patterns were indicative of spruce’s more intensive resource use strategy and competitive advantage over aspen in that layer. Aspen FRB in the organic soil did not differ significantly between pure and mixed stands, but increased in the mineral soil of mixed stands. Since we did not observe a significant difference in the nutrient content of the mineral soil layer between pure aspen and mixed stands, we concluded that aspen may experience competitive exclusion in the organic layer by spruce. Aspen exhibited an extensive nutrient uptake strategy in the organic layer of mixed stands: higher FRB and lower RTD than spruce. In mixed stands, the differences in aspen rooting patterns between the organic and mineral layers suggested the use of contrasting nutrient uptake strategies along the soil profile. We speculate that the stronger spatial separation of the roots of spruce and aspen in mixed stands likely contribute to a higher partitioning of their nutrient uptake along the soil profile. These results indicate the competitive exclusion of aspen by spruce in boreal mixedwoods, which likely occurs in the soil organic layer.
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Shin, Paik-Kyun, Palanisamy Kumar, Abhirami Kumar, Santhakumar Kannappan et Shizuyasu Ochiai. « Effects of Organic Solvents for Composite Active Layer of PCDTBT/PC71BM on Characteristics of Organic Solar Cell Devices ». International Journal of Photoenergy 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/786468.
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Bulk heterojunction (BHJ) structure based active layers of PCDTBT/PC71BM were prepared by using different organic solvents for fabrication of organic solar cell (OSC) devices. Mixture of precursor solutions of PCDTBT/PC71BM in three different organic solvents was prepared to fabricate composite active layers by spin-coating process: chloroform; chlorobenzene; o-dichlorobenzene. Four different blend ratios (1 : 3–1 : 6) of PCDTBT: PC71BM were adopted for each organic solvent to clarify the effect on the resulting OSC device characteristics. Surface morphology of the active layers was distinctively affected by the blend ratio of PCDTBT/PC71BM in organic solvents. Influence of the blend ratio of PCDTBT/PC71BM on the OSC device parameters was discussed. Performance parameters of the resulting OSC devices with different composite active layers were comparatively investigated. Appropriate blend ratio and organic solvent to achieve better OSC device performance were proposed. Furthermore, from the UV-Vis spectrum of each active layer prepared using the PCDTBT/PC71BM mixed solution dissolved with different organic solvents, a possibility that the nanophase separation structure inside their active layer could appear was suggested.
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Heutz, Sandrine, Paul Sullivan, Brett M. Sanderson, Stephan M. Schultes et Tim S. Jones. « Molecular Thin Films for Optoelectronic Applications ». Solid State Phenomena 121-123 (mars 2007) : 373–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.373.
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Organic molecular beam deposition (OMBD) is used for co-evaporation of copper phthalocyanine (CuPc) and C60 to form mixed films. Although pure single layers are crystalline, mixing leads to amorphous films in most cases, although phase segregation occurs for high concentrations of C60. An underlying CuPc single layer suppresses the segregation and leads to a homogeneous CuPc/C60 mixed film for all layer compositions. These effects are exploited in photovoltaic (PV) devices, where new architectures to improve device performance are investigated. Mixing the CuPc and C60 improves device performance, with the maximum efficiency (ηp = 1.17%) reached for devices containing 75% CuPc in the mixed layer, surrounded by pure layers at the electrode interfaces.
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Guan, Xi, Yufei Wang, Shang Feng, Jidong Zhang, Qingqing Yang, Binyuan Liu et Dashan Qin. « Improving the stabilities of organic solar cells via employing a mixed cathode buffer layer ». European Physical Journal Applied Physics 95, no 3 (septembre 2021) : 30201. http://dx.doi.org/10.1051/epjap/2021210151.
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Organic solar cells (OSCs) have been fabricated using cathode buffer layers based on bathocuproine (BCP) and 4,4'-N,N'-dicarbazole-biphenyl (CBP). It is found that despite nearly same power conversion efficiencies, the bilayer of BCP/CBP shows increased thermal stability of device than the monolayer of BCP, mostly because upper CBP thin film stabilizes under BCP thin film. The mixed layer of BCP:CBP gives slightly decreased efficiency than BCP and BCP/CBP, mostly because the electron mobility of the OSC using BCP:CBP is decreased than those using BCP and BCP/CBP. However, the BCP:CBP increases thermal stability of device than BCP and BCP/CBP, ascribed to that the BCP and CBP effectively inhibit reciprocal tendencies of crystallizations in the mixed layer. Moreover, the BCP:CBP improves the light stability of device than the BCP and BCP/CBP, because the energy transfer from BCP to CBP in in the mixed layer effectively decelerates the photodegradation of BCP. We provide a facial method to improve the stabilities of cathode buffer layers against heat and light, beneficial to the commercial development of OSCs.
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Hansen, Poul Lenvig, et Holger Lindgreen. « Structural investigations of mixed-layer smectite-illite clay minerals from North Sea oil source rocks ». Proceedings, annual meeting, Electron Microscopy Society of America 45 (août 1987) : 374–75. http://dx.doi.org/10.1017/s0424820100126664.
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The purpose of the present investigation is to identify mixed-layering between illite and smectite in oil source rocks with HREM and electron diffraction. Smectite and mica are both groups within the 2:1 type of layer silicates. Illite is a commonly used term for micas in the fraction less than 2 microns. Illite has a fixed d(001) spacing of 10A. Smectite is able to swell from 10A to more than 18A under uptake of water or organic polar molecules. Mixed-layer illite-smectite is built of alternating layers of illite and smectite. Smectite and illite layers are recognized by x-ray diffraction (XRD) from their swelling characteristics, but cannot be distinguished in this way in HREM, because smectite layers tend to contract to 10A by evaporation of water in the vacuum of the microscope. Illites are identified by HREM as small packets showing very regular lattice fringes and smectites as highly imperfect, anastomosing layers showing very irregular lattice fringes (1).
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Li, Zuchuan, et Nicolas Cassar. « A mechanistic model of an upper bound on oceanic carbon export as a function of mixed layer depth and temperature ». Biogeosciences 14, no 22 (14 novembre 2017) : 5015–27. http://dx.doi.org/10.5194/bg-14-5015-2017.
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Abstract. Export production reflects the amount of organic matter transferred from the ocean surface to depth through biological processes. This export is in large part controlled by nutrient and light availability, which are conditioned by mixed layer depth (MLD). In this study, building on Sverdrup's critical depth hypothesis, we derive a mechanistic model of an upper bound on carbon export based on the metabolic balance between photosynthesis and respiration as a function of MLD and temperature. We find that the upper bound is a positively skewed bell-shaped function of MLD. Specifically, the upper bound increases with deepening mixed layers down to a critical depth, beyond which a long tail of decreasing carbon export is associated with increasing heterotrophic activity and decreasing light availability. We also show that in cold regions the upper bound on carbon export decreases with increasing temperature when mixed layers are deep, but increases with temperature when mixed layers are shallow. A meta-analysis shows that our model envelopes field estimates of carbon export from the mixed layer. When compared to satellite export production estimates, our model indicates that export production in some regions of the Southern Ocean, particularly the subantarctic zone, is likely limited by light for a significant portion of the growing season.
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Kobayashi, Kazuko. « Organic Components of Moxa ». American Journal of Chinese Medicine 16, no 03n04 (janvier 1988) : 179–85. http://dx.doi.org/10.1142/s0192415x88000261.
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Moxa was soaked in a mixed solvent of chloroform, menthanol and water (5:5:1) at room temperature for 7 days, and the supernatant solution was seperated into two layers by the addition of water. Heptatriacontane (C37H76), confirmed by measurements of 1H and 13C-NMR spectra and melting point, was obtained from the chloroform layer, while condensed tannins having catechol derivatives were found in the methanol-water layer. Each ratio of C37H76 in several kinds of moxas to the total weight of the moxa was similiar in both high-class and low-class moxas, but that of the tannins was much less in the former than the latter. Comparing the burning-temperature from 25°C to the highest temperature was longer in the treated moxa. Removal of C37H76 from the original moxa seems to decelerate the burning of moxa.
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Akkina, Subhash, et Marcus R. Bond. « Bis(1,2,3-trimethylpyridinium) Octa(μ2-bromido)Tetrabromidopentacuprate(II) : Linear, Quasi-Planar Pentacopper(II) Oligomers Stacked to Form Egg-Tray Layers ». Crystals 12, no 9 (7 septembre 2022) : 1270. http://dx.doi.org/10.3390/cryst12091270.
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The crystal structure of (1,2,3-trimethylpyridnium)2Cu5Br12 provides the second reported example of a fully halogenated, linear, quasi-planar, bibridged pentacopper(II) oligomer. The oligomers are aggregated into crosshatched layers that defy traditional notions and notations for quasi-planar oligomer stacking. The regularly arranged voids in the layers are occupied by inversion-related organic cation pairs similar to eggs in an egg-tray. The cross-hatched layer structure arises from a particular stacking of mixed organic cation/pentacopper oligomer sheets. The sheets consist of oligomers placed in a herringbone arrangement separated by zipper-like ribbons of organic cations in a structural motif similar to that found in other 1,2,3- or 1,2,6-trimethylpyridinium halidocuprate(II) structures. Alternative stacking of the sheets leads, on the other hand, to a conventional stacking pattern that conforms to traditional stacking descriptions. Interpretation of these structures in terms of the stacking of mixed cation/anion sheets, as is often performed for ABX3 systems, provides a complementary method for understanding these structures as well as providing a means to describe systems that are not easily described by traditional stacking notation.
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Seo, Ji Hoon, Jung Sun Park, Suk Jae Lee, Bo Min Seo, Kum Hee Lee, Jung Keun Park, Seung Soo Yoon et Young Kwan Kim. « Efficient white organic light-emitting diodes with mixed electron transporting layers ». Journal of Mechanical Science and Technology 25, no 1 (janvier 2011) : 17–19. http://dx.doi.org/10.1007/s12206-010-1007-y.
Texte intégralThèses sur le sujet "Mixed organic layers"
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Bou, Rahhal Elie. « Couches organiques à fonctionnalité TEMPO : de la conception par ingénierie de surface innovante à l’application en électrocatalyse ». Electronic Thesis or Diss., Angers, 2024. https://dune.univ-angers.fr/documents/dune19187.
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La fonctionnalisation de surface progresse avec l’évolution des ingénieries permettant d'ajuster les propriétés structurelles des films déposés. Les plateformes catalytiques à base de TEMPO bénéficient de ces avancées, car elles requièrent une optimisation de leurs performances à l’état confiné. Cependant, la stabilité et l'organisation structurelle des motifs TEMPO sur des surfaces conductrices posent des défis limitant son plein potentiel. Ce projet de thèse explore une stratégie innovante d'ingénierie de surface basée sur l'adaptation de la structure moléculaire de sels de diazonium pour ajuster la composition et la structure des couches obtenues par réduction de ces derniers, un défi difficile à surmonter avec des conceptions moléculaires conventionnelles. Cette approche a effectivement permis d’augmenter la densité des espèces immobilisées et de renforcer les interactions intermoléculaires au sein de la monocouche organique. De plus, il a été montré dans le cadre de cette étude, que les agents de diazotation utilisés pour synthétiser le sel influencent l'état redox du TEMPO, impactant ainsi l'efficacité d'immobilisation. En adaptant la structure des sels de diazonium, il a été possible de concevoir des surfaces bifonctionnelles d’épaisseur et de composition contrôlées, générant des ratios de dilution de surface calibrés, permettant de maximiser l'accessibilité des sites catalytiques. Des tests électrocatalytiques préliminaires ont démontré que les couches à base de TEMPO diluées présentent une activité électrocatalytique accrue vis à vis de l'oxydation électro-assistée des alcools. Ces résultats offrent des perspectives prometteuses pour la conception de couches à base de TEMPO, ouvrant la voie à une meilleure stabilité et une meilleure efficacité des catalyseurs engagés dans des transformations organiquesSurface functionalization advances as engineering techniques evolve to adjust the structural properties of deposited films. TEMPO-based catalytic platforms benefit from these advancements, as they require performance optimization in confined states. However, the stability and structural organization of TEMPO motifs on conductive surfaces present challenges that limit their full potential. This thesis project explores an innovative surface engineering strategy based on adapting the molecular structure of diazonium salts to adjust the composition and structure of layers formed by their reduction—an issue difficult to overcome with conventional molecular designs. This approach has effectively increased the density of immobilized species and strengthened intermolecular interactions within the organic monolayer. Moreover, this study has shown that the diazotization agents used to synthesize the TEMPO-derivatized diazonium salt influence the redox state of TEMPO entity, and subsequently impacting immobilization efficiency. With such structural modification of the conventional design of diazonium salts, it was possible to design bi-functional surfaces with controlled thickness and composition, generating calibrated surface dilution ratios to optimize catalytic site accessibility. Preliminary electrocatalytic tests demonstrated that diluted TEMPO-based layers exhibit enhanced electrocatalytic activity for electro-assisted alcohol oxidation. These results offer promising prospects for the design of TEMPO-based layers, paving the way for improved stability and efficiency of catalysts in organic transformations
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Aversa, Pierfrancesco. « Primary Defects in Halide Perovskites : Effect on Stability and Performance for Photovoltaic Applications Effect of organic PCBM Electron transport Layers on natural and post-irradiation ageing of optical absorption and emission in methyl ammonium lead triiodide spin –coated on p-i-n Solar Sell Substrates Effect of organic PCBM Electron transport Layers on natural and post-irradiation ageing of optical absorption and emission in triple cation lead mixed halide perovskite spin –coated on p-i-n Solar Sell Substrates Electron Irradiation Induced Ageing Effects on Radiative Recombination Properties of methylammonium lead triiodide layers on p-i-n solar cell substrates Electron Irradiation Induced Ageing Effects on Methylammonium Lead Triiodide Based p-i-n Solar Cells Electron Irradiation Induced Ageing Effects on Radiative Recombination Properties of Quadruple Cation Organic-Inorganic Perovskite Layers ». Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX050.
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Ces onze dernières années ont vu apparaitre les pérovskites organiques inorganiques hybrides (HOIPs) comme un passionnant domaine de recherche pour leur application potentielle dans les technologies du photovoltaïque (PV) en raison de leurs exceptionnelles propriétés optoélectroniques et de leur facilité de mise en oeuvre. Cependant, les matériaux HOIPs ont plusieurs inconvénients dont leur manque de stabilité en conditions opérationnelles. Améliorer celle-ci est l'un des plus grands défis à relever avant commercialisation. La formule générale est (A1,A2,A3,A4)Pb(X1,X2)3, où les sites A occupés par une distribution de 1 à 4 cations métalliques/organiques et les sites X par celle d’anions halogénures. Les défauts lacunaires natifs sont considérés comme une cause possible de dégradation des cellules solaires HOIPs. L'objectif de ce travail est de comprendre le rôle des défauts dans la stabilité à long terme des matériaux PV HOIPs. A cette fin, des défauts primaires ont été introduits de manière contrôlée par irradiation avec des électrons de haute énergie (1MeV) dans des lots de couches et cellules solaires (SCs) à base de divers composés HOIPs. Il s'agit notamment du prototype PV HOIPs, MAPbI3 (A1PbX13), et de nouveaux composés mixtes d’halogénures à triple ou quadruple cations, (CsMAFA)Pb(I1-xBrx)3 (A3PbX23) ou (GACsMAFA)Pb(I1-yBry)3 (A4PbX23). Les couches sont fabriquées selon la même procédure que les couches actives SCs et, ensuite, traitées dans des conditions similaires. Pour A1PbX13/A3PbX23, la structure SC est de type p-i-n avec des couches organiques pour le transport des trous et des électrons (HTL/ETL). Les couches sont déposées sur le substrat verre/ITO/HTL (PEDOT:PSS) sans ou avec couche supérieure ETL (PCBM). Pour A4PbX23, la structure SC est de type n-i-p avec des couches ETL inorganiques (TiO2) et HTL organiques (Spiro-OMeTAD). Les couches sont directement déposées sur du verre.La spectroscopie d'annihilation de positons donne une évidence directe de l'existence de défauts lacunaires natifs et induits par irradiation dans chaque composé. Les spectres d’absorbance en fonction de l’énergie montrent que le vieillissement naturel et après irradiation génère différentes populations de défauts dans chaque composé. De plus, celles-ci pour A1PbX13 et A3PbX23 diffèrent selon l'absence ou la présence de la couche supérieure ETL. Les populations de défauts évoluent pendant au moins 3 mois. Le vieillissement modifie (i) la bande interdite, (ii) les queues de bande de conduction/valence et (iii) l'absorption optique via des niveaux électroniques profonds. Les effets d’illumination sous laser varient aussi en fonction du vieillissement. L’asymétrie des pics de photoluminescence (PL) dans chaque composé sous illumination laser continue reflète une superposition de raies d’émission gaussiennes à énergie, FWHM et hauteur évoluant avec le temps d'illumination. Les transitions d'émission impliquent des niveaux électroniques localisés peu profonds dans A3PbX23/A4PbX23 et résonnants dans A1PbX13. De tels effets durent au moins 3 mois dans A4PbX23. Ces niveaux électroniques sont attribués à des populations de défauts spécifiquement induits par illumination. Le vieillissement naturel et après irradiation donne des spectres PL à décroissance temporelle résolue en une ou deux exponentielles. Le nombre et la durée de vie sont fortement influencés par l’irradiation initiale et la composition. Une amélioration frappante du fonctionnement PV pour le type SC p-i-n est induite par le vieillissement dû à l'irradiation. Le rendement quantique externe et les performances PVs ont des valeurs plus élevées pour l’état irradié que de référence durant 6 à 12 mois de vieillissement. Cela prouve que l'ingénierie des défauts par irradiation d'électrons à haute énergie a le potentiel de fournir des voies de traitement innovantes pour améliorer la stabilité à long terme des performances photovoltaïques HOIPsDuring the last eleven years, Hybrid Organic Inorganic Perovskites (HOIPs) materials have emerged as an exciting topic of research for potential application in solar cell technologies due to their outstanding optoelectronic properties and processing advantages. However, HOIPs materials suffer from several drawbacks with, in peculiar, their lack of stability under operational conditions (light, bias, environment…). To improve this stability is one of the biggest challenges to be addressed before commercialization. The general formula for HOIPs is (A1,A2,A3,A4)Pb(X1,X2)3, where the A sites can be occupied by a distribution of 1 to 4 metallic/organic cations and X sites with halide anions. The role of native vacancy defects has been questioned as a possible cause for HOIPs solar cells degradation. The aim of this work is to understand the defect role in long term stability of HOIPs materials for photovoltaics. For this reason, primary defects were introduced in a controlled way via high energy electron irradiation (1MeV) in sets of layers and solar cells (SCs) fabricated using various HOIPs compounds. Those include the photovoltaic HOIPs prototype, MAPbI3 (A1PbX13), and emergent triple or quadruple cation mixed halide HOIPs, (CsMAFA)Pb(I1-xBrx)3 (A3PbX23) or (GACsMAFA)Pb(I1-yBry)3 (A4PbX23). The HOIPs layers are fabricated according to the same procedure as the HOIPs active SC layers and, subsequently, treated in similar conditions. For A1PbX13 and A3PbX23, the solar cells are of the p-i-n structure with organic hole and electron transport layer (HTL/ETL). The HOIPs layers are deposited on the glass/ITO/HTL (PEDOT:PSS) substrate without or with the top ETL layer (PCBM). For A4PbX23, the solar cells are of the n-i-p type with inorganic ETL (TiO2) and organic HTL (Spiro-OMeTAD) layers. The layers are directly deposited on glass without the ETL layer.Positron Annihilation Spectroscopy (PAS) gives direct evidence for native vacancy-type defects and irradiation induced ones in layers of each HOIP compound. The energy dependence of absorbance shows that natural and after irradiation ageing generates different defect populations in each HOIP compound. These populations strikingly also differ depending on the absence or presence of the top ETL layer for the A1PbX13 and A3PbX23 compounds. The defect populations evolve over ageing duration as long as 3 months. The prominent effects of ageing include (i) band gap modification, (ii) tailing of conduction/valence band extrema and (iii) optical absorption via deep subgap electronic levels. Illumination effects under laser also vary with ageing for each HOIP compound. Asymmetric photoluminescence (PL) peaks in each compound under continuous laser illumination reflect that radiative emission involves Gaussian emission rays with energy, FWHM and height evolving with illumination time. The emission transitions involve shallow localized electronic levels in A3PbX23 and A4PbX23 and resonant ones in A1PbX13. These electronic levels are attributed to specifically illumination-induced defect populations. Natural and after irradiation ageing result in PL decay lifetime spectra resolved into one or two exponential decay components. The decay components number and lifetime are strongly affected by the initial production of irradiation defects and HOIPs composition. Such effects last over 3 months at least in A4PbX23. The p-i-n solar cells exhibit most striking irradiation ageing induced photovoltaics performance. The External Quantum Efficiency (EQE versus photon energy) and the photovoltaic performance (I-V under illumination) of the irradiated solar cells have higher values than those in the reference SCs after 6 to 12 months of ageing. This gives evidence that defect engineering via high energy electron irradiation has a potential for providing innovative processing pathways to enhance the long-term stability of HOIPs photovoltaic performance
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Pachoumi, Olympia. « Metal oxide/organic interface investigations for photovoltaic devices ». Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/246263.
Texte intégralRésumé :
This thesis outlines investigations of metal oxide/organic interfaces in photo-voltaic devices. It focuses on device instabilities originating from the metal oxide layer surface sensitivity and it presents suggested mechanisms behind these in- stabilities. A simple sol-gel solution deposition technique for the fabrication of stable and highly performing transparent conducting mixed metal oxides (ZnMO) is presented. It is demonstrated that the use of amorphous, mixed metal oxides allows improving the performance and stability of interfacial charge extraction layers for organic solar cells. Two novel ternary metal oxides, zinc-strontrium- oxide (ZnSrO) and zinc-barium-oxide (ZnBaO), were fabricated and their use as electron extraction layers in inverted organic photovoltaics is investigated. We show that using these ternary oxides can lead to superior devices by: prevent- ing a dipole forming between the oxide and the active organic layer in a model ZnMO/P3HT:PCBM OPV as well as lead to improved surface coverage by a self assembled monolayer and promote a significantly improved charge separation efficiency in a ZnMO/P3HT hybrid device. Additionally a spectroscopic technique allowing a versatility of characterisa- tion for long-term stability investigations of organic solar cells is reported. A device instability under broadband light exposure in vacuum conditions for an inverted ZnSrO/PTB7:PC71BM OPV is observed. Direct spectroscopic evidence and electrical characterisation indicate the formation of the PC71BM radical an- ion associated with a loss in device performance. A charge transfer mechanism between a heavily doped oxide layer and the organic layers is suggested and dis- cussed.
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Pfützner, Steffen. « Studies on Organic Solar Cells Composed of Fullerenes and Zinc-Phthalocyanines ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-83486.
Texte intégralRésumé :
This work deals with the investigation and research on organic solar cells. In the first part of this work we focus on the spectroscopical and electrical characterization of the acceptor molecule and fullerene derivative C70. In combination with the donor molecule zinc-phthalocyanines (ZnPc) we investigate C70 in flat and bulk heterojunction solar cells and compare the results with C60 as acceptor. The stronger and spectral broader thin film absorption of C70 and thus enhanced contribution to photocurrent as well as the similar electrical properties with respect to C60 result in higher power conversion efficiencies. In the second part, modifications of the blend layer morphology of a C60:ZnPc bulk heterojunction solar cell are considered. Using substrate heating during co-deposition of acceptor and donor, the molecular arrangement is influenced. Due to the additional thermal energy at the substrate the blend layer morphology is improved and optimized for a substrate heating temperature of 110°C. With transmission electron microscopy, molecular phase separation of C60 and ZnPc and the formation of polycrystalline ZnPc domains in a lateral dimension on the order of 50 nm are detected. Mobility measurements show an increased ZnPc hole mobility in the heated blend layer. The improved charge carrier percolation and transport are confirmed by the enhanced performance of such bulk heterojunction solar cells. Furthermore, we show a strong influence of the pre-deposited p-doped hole transport layer on the molecular phase separation. In the third part, we study the dependency of the open circuit voltage on the mixing ratio of C60 and ZnPc in bulk heterojunction solar cells. For the different mixing ratios we determine the ionization potentials of C60 and ZnPc. Over the various C60:ZnPc blends from 1:3 - 6:1, the ionization potentials change linearly, but different from each other and exhibit a correlation to the change in open circuit voltage. Depending on the mixing ratio an intrinsic ZnPc layer adjacent to the blend leads to injection barriers which result in reduced open circuit voltage. We hence determine a voltage loss dependent on ZnPc layer thickness and barrier heightDiese Arbeit beschäftigt sich mit der Untersuchung und Forschung an organischen Solarzellen und gliedert sich in drei Teile. Im ersten Teil wird auf die spektroskopische und elektrische Charakerisierung des Fullerenderivates C70 eingegangen, welches als Akzeptormolekül in Kombination mit dem Donormolekül Zink-Phthalocyanin (ZnPc) in Flach- und Mischschichtheteroübergänge organischer Solarzellen Anwendung findet. Dabei wird das Molekül mit dem bisherigen Standard Akzeptormolekül C60 verglichen. Die deutlich stärkere und spektral verbreiterte Dünnschichtabsorption von C70, sowie die vergleichbaren elektrischen Eigenschaften zu C60 führen zu einer Effizienzsteigerung in den Flach- und Mischschichtsolarzellen, welche maßgeblich durch die Erhöhung des Kurzschlussstromes erreicht wird. Im zweiten Teil widmet sich diese Arbeit der Morphologiemodifizierung des Mischschichtsystems C60:ZnPc, welche durch Heizen des Substrates während der Mischverdampfung von Akzeptor- und Donormolekülen in organischen Mischschichtsolarzellen erreicht werden kann. Es wird gezeigt, dass mit der zusätzlichen Zufuhr thermischer Energie über das Substrat die Anordnung der Moleküle in der Mischschicht beeinflusst werden kann. Unter Verwendung eines Transmissionselektronmikroskops lässt sich für die Mischschicht mit der optimalen Solarzellensubstrattemperatur von 110°C eine Phasenseparation von C60 und ZnPc unter Ausbildung von polykristallinen ZnPc Domänen in der lateralen Dimension von 50 nm nachweisen. Mit zusätzlichen Messungen der Ladungsträgerbeweglichkeiten des Mischschichtsystems kann die verbesserte Perkolation und Löcherbeweglichkeit von ZnPc für die Steigerung der Performance geheizter Solarzellen bestätigt werden. Desweiteren wird gezeigt, dass die Ausbildung einer Phasenseparation sehr stark von der darunter liegenden Molekülschicht z.B. der p-dotierte Löchertransportschicht abhängig ist. Im letzten und dritten Teil geht die Arbeit auf die Abhängigkeit der Klemmspannung von der Mischschichtkonzentration von C60 und ZnPc ein. Für die unterschiedlichen Volumenkonzentrationen von C60:ZnPc zwishen 6:1 und 1:6 kann gezeigt werden, dass sich die Ionisationspotentiale von C60 und ZnPc über einen großen Bereich linear und voneinander verschieden verändern und mit den absoluten Änderung der offenenen Klemmspannung korrelieren. Desweiteren wird gezeigt, dass sich durch eine zusätzlich an die Mischschicht angrenzende intrinsische ZnPc Schicht, abhängig von der Mischschichtkonzentration, Injektionsbarrieren ausbilden, welche nachweislich einen Spannungsverlust bedingen. Dabei kann gezeigt werden, dass der Spannungsverlust mit der ZnPc Schichtdicke und der Barrierenhöhe korreliert
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Lesieur, Pierre. « Etude de l'orientation moléculaire dans les films de Langmuir-Blodgett ». Paris 6, 1986. http://www.theses.fr/1986PA066290.
Texte intégralRésumé :
Ce travail constitue une caractérisation des films de Langmuir-Blodgett par résonance paramagnétique électrique et par diffusion Raman résonante en lumière polarisée. Les films sont constitués de multicouches, mixtes ou alternées, de porphyrines amphiphiles et d'acide docosanoïque. Le sujet porte sur l'orientation des macrocycles porphyriniques par rapport au substrat supportant les couches
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Liu, Shun-Wei, et 劉舜維. « Lifetime Study of Organic Light Emitting Devices by Using Mixed Layer Technology ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/87803391267996537222.
Texte intégralRésumé :
碩士長庚大學
機械工程研究所
91
Unlike traditional Liquid-Crystal Displays (LCDs), Organic Light Emitting Devices (OLEDs) are self-luminous and need no backlighting. Despite these advantages, OLEDs are not widely commercialized due to its short operation lifetime. In this thesis, the lifetime mechanism in OLEDs, where the device structure based on a mixed emitting layer (EML), is investigated in terms of carrier transport and direct holes-electrons recombination. The mixed EML is sandwiched between the hole and electron transport layers. From accelerated degradation tests, the operation lifetime of optimal mixed layer (ML) device is considerably improved over the heterojunction (HJ) OLEDs, which shows the lifetime of about 60 h with initial luminance of 10,000 cd/m2. This significant improvement in device lifetime is attributed to the elimination of the organic-organic interface. In addition, the luminance reaches 244,100 cd/m2 at 8V, which corresponds to a luminous efficiency of 4.34 cd/A. These results demonstrate that the mixed EML can extend the performance of OLEDs without significantly changing the device structure or organic material.
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Hsu, Jhe-Hao, et 許哲豪. « The Luminescence Study of Blue Organic Light-Emitting Diodes Using Mixed Emitting Layer ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/80217826816808518899.
Texte intégralRésumé :
碩士輔仁大學
化學系
96
In this experiment,we present and analyze the device performance of mixed layer organic light-emitting devices(OLEDs). The mixed layer material in this device consists of emitting layer(EML) coevaporated with electron transport layer(ETL) and hole transport layer(HTL),respectively. We coevaporate the hole transport material TPD and emitting material DPVBi and use it as the EML. This mixed layer structure blurs the HTL/EML interface. The blurred interface reduce the carrier accumulation and reduce driving voltage,but adjust luminous mechanism. In order to prevent exciton forming in TPBi, we use BCP as hole blocking layer. Therefore,it keep emission wavelength of DPVBi and improve device luminous performance. the max luminance is 12519.43 cd/m2. The luminous power efficiency is 1.71 cd/A The device was made by mixing electron transport layer(TPBI) and emitting layer(DPVBi) in the ratio 1:1.This design could confine the exciton recombination at the mixed layer,and EL emission spectrum is the same.As a result,,it enhance luminous behavior and the max luminance is 12519.43 cd/m2.In other hand,when the mixed ratio change from 1:1 to 2:1,the electron-hole balance is achieved in the emitting layer and high currenent density is shown at low operation voltage.The performance has shown the external quantum efficiency and luminous power efficiency are 2.37% and 2.10 cd/A,respectively.
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Lin, Mou-Zhong, et 林茂仲. « Using NPB:Alq3 Mixed Layer to Improve the Efficiency of Organic Light Emitting Diodes ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/30667070382289525906.
Texte intégralRésumé :
碩士義守大學
電子工程學系
92
In organic materials, the mobility of the holes(μp , 10-4 cm2/Vs)) are much fast than the electrons(μn , 5x10-6 cm2/Vs). The extra holes will decrease the efficiencies of the light emission. Therefore, the most important issue is to balance the amount of the holes and electrons in the organic light emitting diode (OLED). There are two common ways to achieve it. First is to increase the electrons mobility. Second is to decrease the holes mobility. In this work, we decrease the holes mobility to improve the combined efficiency between the holes and electrons. We inserted a NPB：Alq3 mixed layer between these two NPB and Alq3 layers to decrease the holes mobility and improve the combined efficiency between the holes and electrons. After inserting the NPB：Alq3 layer, the current density of the device( ITO/ MTDATA（15 nm）/ NPB[（60-X）nm]/NPB：Alq3 (Y wt%)(X nm) / Alq3（60 nm）/ LiF(0.7 nm)/ Al(180 nm)) is decreased obviously. This result suggests that NPB：Alq3 layer could delay the holes mobility. The optimum concentration in our device is 30 wt% while the total thickness is 30nm. Finally, we also discuss the possibility of emission light in the NPB：Alq3 layer and the applications of red OLEDs in the future.
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Tsai, Chih-Hung, et 蔡志鴻. « Highly Stable Organic Light Emitting Devices with a Uniformly Mixed Hole Transport Layer ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/38963711181445834088.
Texte intégralRésumé :
碩士國立交通大學
應用化學系所
93
In this thesis, highly stable organic light emitting devices was made by using a uniformly mixed hole transport layer (UM-HTL) composed of a mixture of 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) and N,N’-bis(1-naphthyl)-N,N’-diphenyl,1,1’-biphenyl-4,4’-diamine (NPB) in a 3:7 (MADN:NPB) ratio. In 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl- 2,3,6,7-tetrahydro-1H,5H,11H-benzo[l]-pyrano[6,7,8-ij]quinolizin-11-one (C-545T) doped green device, the stability of device with a UM-HTL can be greatly improved to 3 times (initial luminance normalized to 100 nits, 52200 hrs) longer than that of the conventional NPB based HTL without deteriorating on its driving voltage, current efficiency and emissive color significantly. This improvement in stability can be attributed to the fact that the accumulations of positive charge in emission layer have been effectively suppressed. Moreover, using UM-HTL in MADN based blue device systems, the stability of device also can be greatly improved to at least 1.5 times longer than that of the conventional NPB based HTL without deteriorating on its driving voltage, current efficiency and emissive color significantly. These results indicated that UM-HTL can improve the stability of device with any kind of emission color without affecting its emission property. Furthermore, UM-HTL has good thin film thermal property to solve the issue of low Tg in conventional HTL materials. Hence, this made UM-HTL a potential candidate to replace the conventional HTL for each emission color.
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Tien-Chun, Lin. « Blue Organic Light-Emitting Device and the Study of the Mixed-Host Emitting Layer ». 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1907200512180100.
Texte intégralChapitres de livres sur le sujet "Mixed organic layers"
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Mopper, Kenneth. « Organic Chemical Dynamics of the Mixed Layer : Measurement of Dissolved Hydrophilic Organics at Sea ». Dans Dynamic Processes in the Chemistry of the Upper Ocean, 137–57. Boston, MA : Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5215-0_12.
Texte intégral
2
Pardasani, R. T., et P. Pardasani. « Magnetic properties of mixed valence organic-based layered vanadium oxide ». Dans Magnetic Properties of Paramagnetic Compounds, 767–68. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-49202-4_372.
Texte intégral
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Povero, P., M. Fabiano et G. Catalano. « Particulate Organic Matter and Nutrient Utilization in the Mixed Layer of the Ross Sea ». Dans Ross Sea Ecology, 121–34. Berlin, Heidelberg : Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-642-59607-0_10.
Texte intégral
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Mosbah, O., F. Z. Sabi, S. M. Terrah, H. Boutchiche, N. Hamamousse, A. Sahila, A. Kaiss et N. Zekri. « Influence of fuel load on the flammability of live Pinus Halepensis needles ». Dans Advances in Forest Fire Research 2022, 1671–74. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_256.
Texte intégralRésumé :
The fuel flammability, combustibility and fire spread properties depend on several parameters. Among these parameters the heat flux, moisture content, wind and the fuel load. Flammable ignition occurs when the emitted organic volatile components flow mixed with air reaches to a minimum rate corresponding to the lower flammability limit. The gas flow of these components depends on the fuel quantity (load) and its temperature. Therefore, ignition time depends on the fuel load. In this work the effect of the load on ignition time of live Pinus Halepensis needles is investigated using a cone calorimeter (providing three incident heat flux intensities). The average fuel moisture content is around 50% in wet basis. Ignition time exhibits an exponential trend for all the incident heat flux intensities considered with a correlation coefficient R^2>0.96. The exponent corresponds to a characteristic load m ̅_0 around 1 kg/m² slightly dependent on the incident flux within statistical errors. For very small loads compared to m ̅_0 ignition time is nearly independent of load, because the time required for water evaporation is neglected compared to that required for volatiles mixture with air to reach the lower flammability limit. For larger loads (in the range 0.38 kg/m² to 1.27 kg/m²), the time required for water evaporation introduces a shift in ignition time which increases linearly with load. Finally, for large loads compared to m ̅_0, the fuel bed thickness becomes larger than the optical length, and only its top layer is heated, transmitting thus heat to the internal layers by conduction. Therefore, the internal layers evaporate water and cool the upper one, leading to exponential of ignition time with the load. For dry fuels, ignition time appears independent of load.
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Sevink, Jan, et Otto Spaargaren. « Weathering and (Holocene) Soil Formation ». Dans The Physical Geography of Western Europe. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780199277759.003.0027.
Texte intégralRésumé :
The soils of western Europe are marked by superficial accumulation of organic matter as a result of its climate being temperate, rather wet, and leading to leaching and soil acidification. Soils are largely of Holocene age, many properties still being determined by their highly varied parent material. Even more prominent are the impacts of man in this densely populated and highly industrialized part of Europe, causing many soils to be partly or completely of anthropogenic origin. In this chapter, these main soil traits, their origin and distribution will be discussed, attention also being paid to the terminology used and its backgrounds. In the temperate, humid climate of western Europe, organic matter tends to decompose slowly, giving rise to accumulation of above-ground litter and to dark-coloured, humus-rich mineral topsoils. The retarded decomposition is associated with a low activity of soil biota and rather massive production of soluble organic acids, and particularly brought about by the prevailing site conditions such as relatively poor drainage, high precipitation, low temperature, and acid parent material. These site conditions are found over large tracts of western Europe, which therefore have acid, nutrient-poor soils with prominent accumulation of organic matter, such as Podzols and Histosols of the North European Lowlands, and Umbrisols of the middle and high altitude mountains. Bioturbation in these soils is generally weak and therefore soils have distinct horizons and a sharp boundary between the organic surface and mineral subsurface horizons, and thus exhibit large contrasts in soil properties with depth. Where parent materials are more basic and capable of neutralizing acids (e.g. limestone and marl) or climatic conditions are more favourable (e.g. in southern France), litter decomposition proceeds faster and soil biota are more active. In such soils, finely divided organic matter is intimately mixed with mineral material, litter layers are thin or absent and soil reaction tends to be neutral to slightly acid. Moreover, soil horizon differentiation is less prominent as a result of bioturbation, particularly by earthworms. The variation in topsoil properties is so prominent that it was immediately recognized in the early days of soil science and led to a still existing terminology for the description of topsoil organic matter.
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Ouakki, Moussa, Zakia Aribou, Khadija Dahmani, Otmane Kharbouch, Elhachmia Ech-chihbi, Mohamed Rbaa, Mouhsine Galai et Mohammed Cherkaoui. « Imidazole Derivative as a Novel Corrosion Inhibitor for Mild Steel in Mixed Pickling Bath ». Dans Handbook of Research on Corrosion Sciences and Engineering, 456–88. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-7689-5.ch017.
Texte intégralRésumé :
Mild steel is a well-known and widely used material in various industries. However, its exposure to aggressive environments limits its use because of its tendency to corrode. This work focuses on the inhibition of corrosion of mild steel by two organic compounds based on Imidazole, namely 2-(4-chlorophenyl)-1,4,5-triphenyl-1H-imidazole and 1,2,4,5-tetraphenyl-1H-imidazole, in mixed pickling bath. The experimental investigation was carried out using several techniques including electrochemical impedance spectroscopy and potentiodynamic polarization. The adsorption process of corrosion inhibitors on the mild steel surface follows Langmuir adsorption model. Surface characterization analysis using scanning electron microscopy coupled with energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) supported the formation of a barrier layer that covers the mild steel surface. Weight loss measurements were also tested using UV-vis spectrometry (UV-vis).
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« Rural Hauntings and Black Sheep : Comic Turns, Violence and Supernatural Echoes in New Zealand’s Gothic Comedy Films ». Dans Comic Gothic, sous la direction de Lorna Piatti-Farnell et Angelique Nairn, 225–38. Edinburgh University Press, 2024. https://doi.org/10.3366/edinburgh/9781399505758.003.0016.
Texte intégralRésumé :
This chapter examines how New Zealand’s cinematic comic Gothic narratives offer an exploration of the insecurities of the nation and the cultural anxieties that affect the country’s identities. By channelling far-reaching preoccupations connected to, among other things, genetic engineering, organic farming, and family dysfunctions, certain New Zealandcomic Gothic films are able to reveal much about the country’s recent violent history, where the landscape is as threatening as it is idyllic. Focusing particularly on examples suchas Housebound (2014) and Black Sheep (2006), the discussion in this chapter explores how the Gothic mixes with what is commonly referred to as ‘Kiwi humour’ – a deadpan style ofcomedy that is not only attuned to local ways of life, but also draws attention to the significance of New Zealand’s geographically isolated position. Ultimately, this chapteruncovers how, through the construction of multiple comic turns that are contextually entangled with life in the twenty-first century, the films both exploit and subvert the iconographiesof Gothic narratives; in so doing, they also create a particular Antipodean comic Gothic mystique, where metaphorical horrors become paradoxically tangible in the layers of theNew Zealand everyday.
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Atkinson, Martin E. « The gastrointestinal system ». Dans Anatomy for Dental Students. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199234462.003.0012.
Texte intégralRésumé :
The mouth and pharynx are the first parts of the digestive system; they are the principal areas of the gastrointestinal system of interest to dental students and practitioners and are fully described in Chapters 25 and 28. The anatomy of the remainder of the system is described briefly to provide a working knowledge for applications in other aspects of undergraduate dental courses such as nutrition. In essence, the digestive tract is a long convoluted tube illustrated in Figure 6.1. It extends from the mouth, via the pharynx, oesophagus, stomach, small intestine, and large intestine to the anal canal. It is formed along most of its length by longitudinal and circular layers of smooth muscle. It is lined throughout by epithelium which shows marked structural differences from region to region to match different functional requirements of secretion of digestive enzymes, absorption of nutrients, and excretion of waste products. The liver and pancreas are large organs essential to the function of the gastrointestinal system. Food is ingested through the mouth and then prepared for swallowing by being broken up and mixed with saliva by the chewing action of the teeth. Saliva has a major lubricant and minor digestive function. The food is formed into a pellet or bolus and is then swallowed by being moved back by the tongue into the pharynx. Once food is in the pharynx, swallowing becomes a reflex mechanism designed to coordinate contraction of muscles to push the food through the pharynx and oesophagus to the stomach as well as ensuring food and drink do not enter the lower respiratory tract. Swallowing is complex, involving several sets of muscles in the head and neck and is described in more detail in Section 29.1. The passage of food along the remainder of the digestive tract is achieved by regular contractions (peristalsis) of the smooth muscle layers in its walls. The oesophagus is a muscular tube about 25 cm in length. It begins in the neck as a continuation of the pharynx and lies posterior to the trachea as it enters the thorax.
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Zhang, X. N., et A. Z. Zhao. « Surface Charge ». Dans Chemistry of Variable Charge Soils. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097450.003.0005.
Texte intégralRésumé :
The surface of soil colloids carries electric charges, and these surface charges are the basic cause for soil to possess a series of surface properties. Soil surface charges affect the chemical properties of the soil through varying the quantity of electric charge and the surface charge density. For example, adsorptions of cations and anions are caused by negative and positive surface charges of the soil, respectively. The amount of ions adsorbed is determined by the quantity of surface charge, whereas the tightness of adsorption is related to charge density. In addition, the migration of ions in soil, the formation of organo-mineral complexes,and the dispersion, flocculation, swelling, and shrinkage are all affected by surface charge properties of the soil. Therefore, surface charge properties have an important bearing on soil structure and plant nutrition. Variable charge soils are characterized by the high content of iron and aluminum oxides. The clay mineralogical composition is dominated by 1:1-type minerals, such as kaolinite. These two factors make the surface charge properties of variable charge soils distinctly different from those of constant charge soils of temperate regions which chiefly containin 2:1-type clay minerals. However, unlike the case for pure variable charge minerals, in variable charge soils there is generally the presence of a certain amount of 2:1-type clay minerals. Therefore, as a mixture of variable charge minerals and constant charge minerals, the surface charge properties of variable charge soils is more complicated. In this chapter, the origin and factors affecting surface charges of the soil as well as the relationship between these charges and soil type will be discussed. Despite the complexity in composition, a soil may be regarded as a mixed system consisting of constant charge surface materials and constant potential surface materials in different ratios (Anderson and Sposito, 1992; Gillman and Uehara, 1980). Examples of the former type such as montmorillonite and vermiculite carry permanent negative charges, while those of the latter type such as iron oxide and aluminum oxide carry variable charges. Commonly found constant charge clay minerals in soils include those layer silicates such as hydrous mica, vermiculite, montmorillonite, and chlorite.
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Barbashova, Iryna. « MASS PEDAGOGICAL EXPERIENCE OF SENSORY DEVELOPMENT OF PRIMARY SCHOOL STUDENTS ». Dans Integration of traditional and innovation processes of development of modern science. Publishing House “Baltija Publishing”, 2020. http://dx.doi.org/10.30525/978-9934-26-021-6-4.
Texte intégralRésumé :
A condition for the effectiveness of sensory development of primary school students is a critical study of the pedagogical experience of its organization. The importance of solving this problem is caused by the fact that school practice lays the foundation of pedagogical science and must take into account both modern scientific achievements and requirements of regulatory state documents. The purpose of the study is to highlight the mass pedagogical experience of sensory development of primary school students. To achieve this goal, written and oral interviews with teachers (questionnaires, interviews, talks) and observation of professional activities were used. It has been revealed that teachers are aware of the meaning of sensory development and distinguish its leading areas – the forming of vision, hearing and touch of schoolchildren; identify students’ typical difficulties in distinguishing mixed colors, complex shapes of objects, sonorous, hissing and whistling consonants, as well as in reproducing the nuances of coloring of objects, the relationship between size and spatial arrangement, inclined and rounded elements of letters, sequence of sounds in an audible word. At the same time, teachers are poorly oriented in the program material of perceptual development, admit insufficient awareness of the laws of sensory processes, and want to know more about the latest techniques and technologies of their forming. Observation of the real educational process allowed to establish a wide range of didactic influences used by educators in order to form different types of students’ perception. Teachers organize studies of colored objects, correcting children's verbal designations of colors and their shades; suggest exercises for superimposing objects of different shapes and sizes (arranging by size, placing figures in given proportions, etc.); form students' ideas about speech sounds (observation of the work of speech organs, modeling the properties of sounds with conditional chips, analysis of the phonetic structure of words, etc.); provide perception of musical works, demonstrate sounds of musical instruments and singing voices, use symbols to record the gradations of sounds in pitch, duration and volume, encourage students to reproduce the properties of musical sounds in singing and rhythmic movements; create conditions for touching objects made of different materials. However, teachers do not pay enough attention to distinguishing and naming color nuances, three-dimensional geometric shapes, symbols of voicedness and voicelessness of consonants, comparison of musical sounds by timbre qualities, and verbal characteristics of tactile sensory impressions. The conducted research proves that the mass pedagogical experience ensures the implementation of program requirements for improving the sensory sphere of primary school students, but shows a lack of teachers’ awareness of children's sensory processes and unstable motivation to solve problems of developing students’ perception. The prospect for further scientific research is to study the program, educational and methodological resources of forming the processes of perception in primary school students.
Actes de conférences sur le sujet "Mixed organic layers"
1
Khadka, Dhruba, Yasuhiro Shirai, Masatoshi Yanagida et Kenjiro Miyano. « Efficient Wide Bandgap Mixed Halide Perovskite Solar Cells Tuning with Electron Transport Layers ». Dans 2nd Asia-Pacific Hybrid and Organic Photovoltaics. Valencia : Fundació Scito, 2017. http://dx.doi.org/10.29363/nanoge.ap-hopv.2018.067.
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Steirer, K. Xerxes, N. Edwin Widjonarko, Ajaya K. Sigdel, Matthew T. Lloyd, David S. Ginley, Dana C. Olson et Joseph J. Berry. « Optimization of organic photovoltaic devices using tuned mixed metal oxide contact layers ». Dans 2010 35th IEEE Photovoltaic Specialists Conference (PVSC). IEEE, 2010. http://dx.doi.org/10.1109/pvsc.2010.5614501.
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Öz, Dilara, et Dr Selina Olthof. « Do substrates matter ? - the impact of hole transport layers on Iodide/Bromide composition in thermally evaporated mixed halide perovskites ». Dans International Conference on Hybrid and Organic Photovoltaics. València : FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2024. http://dx.doi.org/10.29363/nanoge.hopv.2024.057.
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Popovic, Zoran D., Hany Aziz, Carl P. Tripp, Nan-Xing Hu, Ah-Mee Hor et Gu Xu. « Improving the efficiency and stability of organic light-emitting devices using mixed emitting layers ». Dans SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, sous la direction de Zakya H. Kafafi. SPIE, 1998. http://dx.doi.org/10.1117/12.332630.
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Schildkraut, Jay S. « Electrooptic polymer films with organic photoconductors ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.fq3.
Texte intégralRésumé :
We describe electrooptic (EO) polymer films that also exhibit photoconductivity. An acrylic polymer containing a stilbene chromophore with a high second-order nonlinear susceptibility was doped with a perylene sensitizer for photocharge generation and a triarylamine hole transporting molecule. A polymer film was fabricated that had an EO coefficient of 2.5 pm/V. Absorption of light by the sensitizer results in a photocurrent and charge trapping. The efficiency of photocharge generation at 515 nm with 120 V applied across a 1.27-µm film was 1.4 × 10-3 mobile charges per absorbed photon. The photorefractive sensitivity was 3.7 × 10-6 cm3/J. We also describe a multi-layer structure with the following layers: an indium tin oxide electrode, an electrooptic polymer film, a mixed perylene-triarylamine film, a pure triarylamine film, and a gold electrode. The two films that contain the triarylamine hole transporting molecule act as a photodiode.
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Aversa, Pierfrancesco, Senol Öz, Eunhwan Jung, Olivier Plantevin, Olivier Cavani, Nadège Ollier, Bernard Geffroy, Sanjay Mathur et Catherine Corbel. « Radiative Recombination in Quadruple Cation Organic-Inorganic Mixed Halide Perovskite Layers : Electron Irradiation Induced Ageing Effects ». Dans nanoGe Fall Meeting 2019. València : Fundació Scito, 2019. http://dx.doi.org/10.29363/nanoge.ngfm.2019.053.
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Aversa, Pierfrancesco, Senol Öz, Eunhwan Jung, Olivier Plantevin, Olivier Cavani, Nadège Ollier, Bernard Geffroy, Sanjay Mathur et Catherine Corbel. « Radiative Recombination in Quadruple Cation Organic-Inorganic Mixed Halide Perovskite Layers : Electron Irradiation Induced Ageing Effects ». Dans nanoGe Fall Meeting 2019. València : Fundació Scito, 2019. http://dx.doi.org/10.29363/nanoge.nfm.2019.053.
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Sancaktar, E., et J. Kuznicki. « Stress-Dependent Water Uptake Behavior of Clay Reinforced Nanocomposite Epoxy ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80549.
Texte intégralRésumé :
Layered silicate nanolayers can be used as alternative inorganic components for the construction of nanostructured hybrid composites. The clay silicate nanolayers possess stable Si-O bonds and high particle aspect ratios comparable to conventional fibers. Their interlayer surface is easily modified by ion-exchange reaction, and the gallery can be intercalated by organic polymer precursors for the formation of organic-inorganic nanocomposites. Exfoliated clay composites contain single, 1 nm thick layers of clay dispersed in the polymer matrix. Owing to the platy morphology of the silicate layers, exfoliated clay nanocomposites can exhibit dramatically improved properties such as barrier and mechanical properties that are not available for conventional composite materials. Since the clay particles scavenge water, the nanocomposite samples initially absorb slightly higher amounts of water in comparison to the no-clay samples, with the water molecules congregating around the clay particles. On the other hand, the presence of these clay particles still hinders diffusion of water through the sample, thus protecting the structural interfaces. In this work, low viscosity liquid aromatic diglycidyl ether of bisphenol A (DGEBA) epoxy resin Epon 815C was mixed with nanoclay at 60°C for 6 hours. The epoxy-clay mixture was then mixed with curing agent DETA (Diethylenetriamine) at 80°C for 4 minutes and cured at 120°C for 3 hours to produce exfoliated clay — epoxy resin system. These samples were used to first optimize the percent clay level for lowest water uptake, and subsequently immersed in water in stressed condition (flexural stress) to assess the effect of stress on nanocomposite epoxy system for its water uptake behavior. The results revealed up to 33% reduction in water uptake for the stressed samples.
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Raghavan, Sathyanarayanan, Ilko Schmadlak, George Leal et Suresh K. Sitaraman. « Cohesive Zone Models to Predict Multiple White Bumps in Flip-Chip Assemblies ». Dans ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-40199.
Texte intégralRésumé :
The drive towards increased functional integration and improved performance in microelectronic devices has led to the introduction of more layers and porous dielectric materials in back end of line (BEOL) stack. These materials have low mechanical strength as well as adhesive strength and thus, interfacial delamination is a major reliability concern for modern microelectronic devices. In this work, we present a cohesive zone element based finite-element model to predict failures observed at the end of flip-chip assembly reflow process. During lead-free flip-chip assembly, thermo-mechanical stresses arise due to the coefficient of thermal expansion (CTE) mismatch between the organic substrate and the silicon die. Such stresses can be high enough to cause cracking of interlayer dielectric layers present in the vicinity of solder bump. In order to predict such failures, mixed mode cohesive zone parameters are first extracted from interfacial fracture characterization experiments of real-life BEOL stacks. Then, the characterized cohesive zone elements are embedded in 2D finite-element models of flip-chip assembly to predict the failure region. The predicted failure region is compared against 2D fracture mechanics based models as well as failure analysis experiment results. Cohesive zone elements are then implemented over multiple bumps to examine simultaneous failure of multiple bumps under reflow assembly, and thus, the effectiveness of cohesive zone elements compared to fracture mechanics approach is demonstrated.
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Gopakumar, Sunil, Francois Billaut, Eric Fremd et Manthos Economou. « Pb-Free Process Development for a High End Storage Area Network Application ». Dans ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33857.
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Lead free solders are being increasingly used in the electronic industry. While most of the electronic products, in terms of volume, are already built lead free, sectors of the industry including high end servers, networking and telecommunications are covered by “lead in solder” exemptions. It is unknown at this point how long these exemptions will last. In addition, many components such as memories have started appearing only in the Pb-free version. As a result, the industry has been pushed to either adopt a mixed assembly process or to transition early to a full Pb-free process. Even though numerous papers have outlined the successful implementation of a Pb-free process, few of them have actually looked at complex high-end multilayer boards in its entirety. This paper focuses on the issues involved in developing an acceptable Pb-free process window for thick, multilayer boards for SMT, Wave soldering, Rework and Press-fit operations. A laminate capable of withstanding Pb-free soldering temperatures was used to construct a 125-mil thick multilayer board with 18 layers which included 8 ground and 10 signal planes. This experiment utilized two popular Pb-free finishes commonly used in the industry: Immersion Silver and high temperature Organic Solderability Preservative (OSP). The widespread SAC 305 alloy with a composition of Sn3.0Ag0.5Cu was used for both SMT and wave soldering. Three sets of assemblies were built: Pb-free, Mixed and Sn/Pb. The mixed assembly mostly used Pb-free components with Sn/Pb solder paste. The impact of increased soldering temperatures on the board, components and reliability of the product were also studied as a part of this research endeavor. Board level reliability tests were conducted by subjecting the boards from 0°C to 100°C Air-to-Air thermal cycling as well as mechanical shock and vibration tests. A suite of reliability and destructive physical analysis (DPA) tests were carried out to establish the quality of the soldering using the eutectic Sn/Pb assembly as the baseline. The study compared the cycling performance of the three sets of assemblies and also looked at the potential impacts of moving to mixed assemblies. Results indicated a reduced process window for Pb-free, especially for the Pb-free wave soldering process due to reduced wetting of the plated through hole barrels as compared to Sn/Pb wave soldering process. The thermal cycling performance of the three sets of assemblies was found to be equivalent after 6000 cycles.